Botulinum toxin type-A (BTX-A) injections have become a common treatment modality for patients su... more Botulinum toxin type-A (BTX-A) injections have become a common treatment modality for patients suffering from muscle spasticity. Despite its benefits, BTX-A treatments have been associated with adverse effects on target muscles. Currently, application of BTX-A is largely based on clinical experience, and research quantifying muscle structure following BTX-A treatment has not been performed systematically. The purpose of this study was to evaluate strength, muscle mass, and contractile material six months following a single or repeated (2 and 3) BTX-A injections into the quadriceps femoris of New Zealand white rabbits. Twenty three skeletally mature rabbits were divided into four groups: experimental group rabbits received 1, 2, or 3 injections at intervals of 3 months (1-BTX-A, 2-BTX-A, 3-BTX-A, respectively) while control group rabbits received volume-matched saline injections. Knee extensor strength, quadriceps muscle mass, and quadriceps contractile material of the experimental group rabbits were expressed as a percentage change relative to the control group rabbits. One-way ANOVA was used to determine group differences in outcome measures (α=0.05). Muscle strength and contractile material were significantly reduced in experimental compared to control group rabbits but did not differ between Experimental groups. Muscle mass was the same in experimental BTX-A and control group rabbits. We concluded from these results that muscle strength and contractile material does not fully recover within six months of BTX-A treatment.
Objectives: Interactions between mechanical and non-mechanical independent risk factors for the o... more Objectives: Interactions between mechanical and non-mechanical independent risk factors for the onset and progression of Osteoarthritis (OA) are poorly understood. Therefore, the goal of the present study was to investigate the in vivo effects of muscle weakness, joint inflammation and the combination on the onset and progression of OA in a rabbit knee joint model. Materials and methods: Thirty 1-year-old female New Zealand White rabbits (average 5.7 kg, range 4.8e6.6 kg) were divided into four groups with one limb randomly assigned to be the experimental side: (1) surgical denervation of the vastus lateralis (VL) muscle; (2) muscle weakness induced by intramuscular injection of Botulinum toxin A (BTX-A); (3) intraarticular injection with Carrageenan to induce a transient inflammatory reaction; (4) combination of Carrageenan and BTX-A injection. After 90 days, cartilage histology of the articular surfaces were microscopically analyzed using the Osteoarthritis Research Society International (OARSI) histology scoring system. Results: VL denervation resulted in significantly higher OARSI scores in the patellofemoral joint (group 1). BTX-A administration resulted in significant cartilage damage in all four compartments of the knee (group 2). Carrageenan did not cause significant cartilage damage. BTX-A combined with Carrageenan lead to severe cartilage damage in all four compartments. Conclusion: Muscle weakness lead to significant OA in the rabbit knee. A transient local inflammatory stimulus did not promote cartilage degradation nor did it enhance OA progression when combined with muscle weakness. These results are surprising and add to the literature the conclusion that acute inflammation is probably not an independent risk factor for OA in this rabbit model.
Objective: Mesenchymal progenitor cells (MPCs) can differentiate into osteoblasts, adipocytes, an... more Objective: Mesenchymal progenitor cells (MPCs) can differentiate into osteoblasts, adipocytes, and chondrocytes, and are in part responsible for maintaining tissue integrity. Recently, a progenitor cell population has been found within the synovial fluid that shares many similarities with bone marrow MPCs. These synovial fluid MPCs (sfMPCs) share the ability to differentiate into bone and fat, with a bias for cartilage differentiation. In this study, sfMPCs were isolated from human and canine synovial fluid collected from normal individuals and those with osteoarthritis (human: clinician-diagnosed, canine: experimental) to compare the differentiation potential of CD90+ vs. CD902 sfMPCs, and to determine if CD90 (Thy-1) is a predictive marker of synovial fluid progenitors with chondrogenic capacity in vitro. Methods: sfMPCs were derived from synovial fluid from normal and OA knee joints. These cells were induced to differentiate into chondrocytes and analyzed using quantitative PCR, immunofluorescence, and electron microscopy. The CD90+ subpopulation of sfMPCs had increased chondrogenic potential compared to the CD902 population. Furthermore, sfMPCs derived from healthy joints did not require a micro-mass step for efficient chondrogenesis. Whereas sfMPCs from OA synovial fluid retain the ability to undergo chondrogenic differentiation, they require micro-mass culture conditions. Overall, this study has demonstrated an increased chondrogenic potential within the CD90+ fraction of human and canine sfMPCs and that this population of cells derived from healthy normal joints do not require a micro-mass step for efficient chondrogenesis, while sfMPCs obtained from OA knee joints do not differentiate efficiently into chondrocytes without the micro-mass procedure. These results reveal a fundamental shift in the chondrogenic ability of cells isolated from arthritic joint fluids, and we speculate that the mechanism behind this change of cell behavior is exposure to the altered milieu of the OA joint fluid, which will be examined in further studies.
International Journal of Molecular Sciences, Aug 11, 2021
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Clinical Orthopaedics and Related Research, Mar 1, 2007
We hypothesized specific growth factors are increased in the elbow capsules of patients with post... more We hypothesized specific growth factors are increased in the elbow capsules of patients with post traumatic elbow contractures. A model of surgically induced joint contracture in rabbit knees was developed to study the growth factor expression in joint contractures. This study demonstrates this model mimics the human condition and analyzes how the growth factor levels decrease with time in rabbit knees with contractures. Reverse transcription polymerase chain reaction was used to measure mRNA levels of transforming growth factor-β1, connective tissue growth factor, ED-A of fibronectin, and α-smooth muscle actin normalized to a housekeeping gene, glyceraldehyde-3phosphate dehydrogenase. In the joint capsules of patients with elbow contractures, mRNA levels were increased for transforming growth factor-β1, connective tissue growth factor, and α-smooth muscle actin. In the joint capsules of rabbit knees with contractures, mRNA levels were increased for transforming growth factor-β1, connective tissue growth factor, ED-A of fibronectin, and αsmooth muscle actin. The mRNA levels for transforming growth factor-β1, connective tissue growth factor, and α-smooth muscle actin decreased with time in rabbit knees. The elevated levels of these myofibroblast up-regulators and fibrogenic growth factors could explain the previously reported increase in myofibroblasts and collagen mRNA levels. The rabbit knee model correlated well with the human post traumatic elbow contractures. A sound anatomic basis for the pathogenesis of joint contractures is known. 9 For elbow joint contractures, surgical release has stressed the importance of removing the joint capsule. 5,30,34 There is an elevated number of myofibroblasts and an increase in the expression of αsmooth muscle actin (α-SMA), a myofibroblast marker, within joint capsules obtained from human elbows with chronic post traumatic contractures. 18 A rabbit model of post traumatic joint contractures has shown similar changes with regard to myofibroblast numbers and α-SMA levels in capsules obtained from knees with chronic contractures. 15 Thus, there is good correlation between the human condition and the animal model. The pathologic process that leads to increases in myofibroblast numbers and α-SMA levels detected in contracted joint capsules is unknown.
Background: Osteoarthritis (OA) is a chronic and painful condition where the articular cartilage ... more Background: Osteoarthritis (OA) is a chronic and painful condition where the articular cartilage surfaces progressively degenerate, resulting in loss of function and progressive disability. Obesity is a primary risk factor for the development and progression of knee OA, defined as the "metabolic OA" phenotype. Metabolic OA is associated with increased fat deposits that release inflammatory cytokines/adipokines, thereby resulting in systemic inflammation which can contribute to cartilage degeneration. There is currently no cure for OA. Prebiotics are a type of dietary fiber that can positively influence gut microbiota thereby reducing systemic inflammation and offering protection of joint integrity in rodents. However, no human clinical trials have tested the effects of prebiotics in adults with obesity suffering from knee OA. Therefore, the purpose of this double-blind, placebo-controlled, randomized trial is to determine if prebiotic supplementation can, through positive changes in the gut microbiota, improve knee function and physical performance in adults with obesity and knee OA. Methods: Adults (n = 60) with co-morbid obesity (BMI > 30 kg/m 2) and knee OA (Kellgren-Lawrence grade II-III) will be recruited from the Alberta Hip and Knee Clinic and the Rocky Mountain Health Clinic and surrounding community of Calgary, Canada, and randomized (stratified by sex, BMI, and age) to prebiotic (oligofructose-enriched inulin; 16 g/day) or a calorie-matched placebo (maltodextrin) for 6 months. Anthropometrics, performance-based tests, knee pain, serum inflammatory markers and metabolomics, quality of life, and gut microbiota will be assessed at baseline, 3 months, 6 months (end of prebiotic supplementation), and 3 months following the end of the prebiotic supplementation.
Mesenchymal stem cells (MSCs) derived from induced pluripotent stem cells (iPSCs) are a promising... more Mesenchymal stem cells (MSCs) derived from induced pluripotent stem cells (iPSCs) are a promising cell source for the repair of skeletal disorders. Recently, neural crest cells (NCCs) were reported to be effective for inducing mesenchymal progenitors, which have potential to differentiate into osteochondral lineages. Our aim was to investigate the feasibility of MSC-like cells originated from iPSCs via NCCs for osteochondral repair. Initially, MSC-like cells derived from iPSC-NCCs (iNCCs) were generated and characterized in vitro. These iNCC-derived MSC-like cells (iNCMSCs) exhibited a homogenous population and potential for osteochondral differentiation. No upregulation of pluripotent markers was detected during culture. Second, we implanted iNCMSC-derived tissue-engineered constructs into rat osteochondral defects without any preinduction for specific differentiation lineages. The implanted cells remained alive at the implanted site, whereas they failed to repair the defects, with only scarce development of osteochondral tissue in vivo. With regard to tumorigenesis, the implanted cells gradually disappeared and no malignant cells were detected throughout the 2-month follow-up. While this study did not show that iNCMSCs have efficacy for repair of osteochondral defects when implanted under undifferentiated conditions, iNCMSCs exhibited good chondrogenic potential in vitro under appropriate conditions. With further optimization, iNCMSCs may be a new source for tissue engineering of cartilage.
Adult mesenchymal stem cells were reported more than 30 years ago. Since then, their potential to... more Adult mesenchymal stem cells were reported more than 30 years ago. Since then, their potential to repair and regenerate damaged or diseased tissues has been studied intensively in both preclinical models and human trials. Most of the need for such tissue repair/regeneration is in older populations, so much of the effort has been performed with autologous cells in older patients. However, success has been difficult to achieve. In the literature, it has been noted that such progenitor cells from younger individuals often behave with more vigorous activity and are functionally enhanced compared to those from older individuals or animals. In addition, cells with the characteristics of mesenchymal stem cells or pluripotent mesenchymal regulatory cells exist in nearly all tissues and organs as pericytes since fetal life. Such evidence raises the possibility that one of the primary roles of these organ-specific cells is to regulate organ growth and maturation, and then subsequently play a ...
Sex-specific differences in biology and physiology likely start at the time of conception and pro... more Sex-specific differences in biology and physiology likely start at the time of conception and progress and mature during the pre-puberty time frame and then during the transitions accompanying puberty. These sex differences are impacted by both genetics and epigenetic alterations during the maturation process, likely for the purpose of preparing for successful reproduction. For females, later in life (~45–50) they undergo another transition leading to a loss of ovarian hormone production at menopause. The reasons for menopause are not clear, but for a subset of females, menopause is accompanied by an increased risk of a number of diseases or conditions that impact a variety of tissues. Most research has mainly focused on the target cells in each of the affected tissues rather than pursue the alternative option that there may be commonalities in the development of these post-menopausal conditions in addition to influences on specific target cells. This review will address some of the...
Journal of Biomedical Science and Engineering, 2021
Over 30 years ago, it was reported by Caplan that cells could be found in various adult tissues a... more Over 30 years ago, it was reported by Caplan that cells could be found in various adult tissues and fluids of a variety of species that could be induced in vitro to progress towards lineages such as chondrogenesis, osteogenesis and adipogenesis with different "cocktails" of reagents. These cells were called Mesenchymal Stem Cells (MSC) to reflect this pluripotency. After 30 years of intense research effort to directly use such cells for the repair or regeneration of damaged or injured tissues, the effort has met with limited in vivo success, but their use for in vitro tissue engineering has met with some success. This failure to live up to expectations for in vivo differentiation success has led Caplan to recently rename these cells Medicinal Signaling Cells (MSC) to reflect other abilities of these cells to secrete mediators and release exosomes containing biologically active molecules that can influence their neighboring cells in a paracrine manner. However, neither of these names completely captures the combined apparent in vivo functioning of MSC and their in vitro abilities to exhibit pluripotent behavior. Thus, it is suggested, based on the attributes of these cells and their tissue and clonal heterogeneity, that an alternative name be applied to these cells and they be described as Pluripotent Mesenchymal Regulatory Cells (PMRC). This name reflects their regulatory function as pericytes in tissues, as well as their well-known immunoregulatory activity when injected into the intra-articular space and their influence on activities such as
Objective/Hypothesis: A recent clinical study of the human lactoferrin peptide PXL01 in sodium hy... more Objective/Hypothesis: A recent clinical study of the human lactoferrin peptide PXL01 in sodium hyaluronate (HA) administrated around repaired tendons in the hand showed significantly improved digit mobility compared with placebo. To investigate the antiadhesive mechanisms of PXL01 in HA, we have used the rabbit lactoferrin peptide, rabPXL01 in HA, in a rabbit model of healing tendons and tendon sheaths. Materials and Methods: On days 1, 3, and 6 after tendon injury and surgical repair, reverse transcription-quantitative PCR (RT-qPCR) was used to assess messenger RNA (mRNA) expression levels for genes encoding the mucinous glycoprotein PRG4 (also called lubricin), and a subset of matrix proteins, cytokines, and growth factors involved in flexor tendon repair. RabPXL01 in HA was administrated locally around the repaired tendons, and the mRNA expression was compared with untreated repaired tendons and tendon sheaths using analysis of variance. Results: We observed, at all time points, ...
Background: Osteoarthritis is one of the leading causes of pain and disability worldwide, and a l... more Background: Osteoarthritis is one of the leading causes of pain and disability worldwide, and a large percentage of patients with osteoarthritis are individuals who are also obese. In recent years, a series of animal models have demonstrated that obesity-inducing diets can result in synovial joint damage (both with and without the superimposition of trauma), which may be related to changes in percentage of body fat and a series of low-level systemic inflammatory mediators. Of note, there is a disparity between whether the dietary challenges commence at weaning, representing a weanling onset, or at skeletal maturity, representing an adult onset of obesity. We wished to evaluate the effect of the dietary exposure time and the age at which animals are exposed to a high-fat and high-sucrose (HFS) diet to determine whether these factors may result in disparate outcomes, as there is evidence suggesting that these factors result in differential metabolic disturbances. Based on dietary exposure time, we hypothesized that rats fed an HFS diet for 14 weeks from weaning (HFS Weanling) would demonstrate an increase in knee joint damage scores, whereas rats exposed to the HFS diet for 4 weeks, starting at 12 weeks of age (HFS Adult) and rats exposed to a standard chow diet (Chow) would not display an increase in knee joint damage scores. Methods: Male Sprague-Dawley rats were fed either an HFS diet for 14 weeks from weaning (HFS Weanling) or an HFS diet for 4 weeks, starting at 12 weeks of age (HFS Adult). At sacrifice, joints were scored using the modified Mankin Criteria, and serum was analyzed for a defined subset of inflammatory markers (Interleukin-6, leptin, monocyte chemoattractant protein-1, and tumor necrosis factor a). Results: When the HFS Weanling and HFS Adult groups were compared, both groups had a similar percent of body fat, although the HFS Weanling group had a significantly greater body mass than the HFS Adult group. The HFS Weanling and HFS Adult animals had a significant increase in body mass and percentage of body fat when compared to the Chow group. Although knee joint damage scores were low in all 3 groups, we found, contrary to our hypothesis, that the HFS Adult group had statistically significant greater knee joint damage scores than the Chow and HFS Weanling groups. Furthermore, we observed that the HFS Weanling group did not have significant differences in knee joint damage scores relative to the Chow group. Conclusion: These findings indicate that the HFS Weanling animals were better able to cope with the dietary challenge of an HFS diet than the HFS Adult group. Interestingly, when assessing various serum proinflammatory markers, no significant differences were detected between the HFS Adult and HFS Weanling groups. Although details regarding the mechanisms underlying an increase in knee joint damage scores in the HFS Adult group remain to be elucidated, these findings indicate that dietary exposure time maybe less important than the age at which an HFS diet is introduced. Moreover, increases in serum proinflammatory mediators do not appear to be directly linked to knee joint damage scores in the HFS Weanling group animals but may be partially responsible for the observed knee joint damage in the adults over the very short time of exposure to the HFS diet.
The role of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) has been highl... more The role of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) has been highlighted in mechanisms underlying inflammatory and neuropathic pain processes. The present study was designed to investigate whether NF-κB signaling is associated with pain-related neuropeptide expression in patients with chronic back pain related to degenerative disc disease (DDD). Intervertebral disc (IVD) tissues were collected from forty DDD patients undergoing disc replacement or fusion surgery, and from eighteen postmortem (PM) control subjects. RELA, NFKB1, CGRP, TAC1, TRPV1, and MMP-3 gene expression were analyzed by RT-qPCR, while NF-κB subunit RelA and NF-κB1–DNA binding in nuclear extracts and calcitonin gene related peptide (CGRP), substance P (SP), and transient receptor potential, subfamily V, member 1 (TRPV1) protein levels in cytosolic extracts of tissues were assessed by enzyme-linked immunosorbent assay (ELISA). An upregulated NF-κB1–DNA binding, and higher CGRP and TRPV1...
objective measures, such as timed walks or sit-to-stand tests. Such objective measures are admini... more objective measures, such as timed walks or sit-to-stand tests. Such objective measures are administered in controlled, laboratory style settings, and may not reflect levels of activity in daily life. With the rapid development of monitoring technology, there is opportunity to characterise the relationship between PROMs and behaviour in a natural setting and to develop methods of passive monitoring of outcome and recovery after surgery. We are working with a multidisciplinary team which has developed a system of low powered sensors that can monitor the health-related behaviours of people living at home. The system includes: sensors for the home environment (measuring temperature, humidity, room occupancy, water and electricity usage) a wrist-band body-worn activity monitor and silhouette (body outline) sensors. The SPHERE system of sensors is now being installed in 100 homes belonging to the general population. Within this cohort we are installing the system in the homes of 20 patients who are about to undergo a total hip or knee replacement (THR/TKR). The study aims to: (a) determine to what extent the sensory data obtained from the SPHERE system is comparable to data obtained from routine clinical measures and PROMs in the assessment of patients' activity, function and recovery processes; (b) investigate whether the sensory data can detect meaningful changes in recovery. Methods: To assess the accuracy and usefulness of the sensory data, in this 1-year observational study, patients will be provided with the sensor system to monitor and record daily continuous measurements. We will make and refine appropriate data learning outcomes with the quantitative data e.g., daily measurements in the weeks parallel to the distribution of PROM assessments pre/post-operative (4e9 days, 6 and 12 weeks) and weekly measurements during the other months. The study will assess the relationships between environmental, behavioural and movement data and the parameters of interest from the PROMs assessments over time. Interviews and focus groups with patients and health professional will provide qualitative data and achieve depth in understanding the accuracy of the data, its usefulness for health professionals in decision making, and if the technology is acceptable. Results: The SPHERE sensor system has been installed in the homes of two patients. We aim to recruit up to 20 patients, (aged 18 years or over) whom are due to undergo a TKR or THR in the UK. Conclusions: This study will provide a unique understanding of home and wearable sensor technology in an orthopaedic population and will compare sensor data with current PROMs.
Obesity, and associated metabolic syndrome, have been identified as primary risk factors for the ... more Obesity, and associated metabolic syndrome, have been identified as primary risk factors for the development of knee osteoarthritis (OA), representing nearly 60% of the OA patient population. In this study, we sought to determine the effects of prebiotic fibre supplementation, aerobic exercise, and the combination of the two interventions, on the development of metabolic knee osteoarthritis in a high-fat/high-sucrose (HFS) diet-induced rat model of obesity. Twelve-week-old male Sprague-Dawley rats were randomized into five groups: a non-exercising control group fed a standard chow diet, a non-exercising group fed a HFS diet, a non-exercising group fed a HFS diet combined with prebiotic fibre supplement, an exercise group fed a HFS diet, and an exercise group fed a HFS diet combined with prebiotic fibre supplement. Outcome measures included knee joint damage, percent body fat, insulin sensitivity, serum lipid profile, serum endotoxin, serum and synovial fluid cytokines and adipokines...
associated with a reduced prevalence of femoral head cartilage defects (OR 0.65, 95% CI 0.46e0.91... more associated with a reduced prevalence of femoral head cartilage defects (OR 0.65, 95% CI 0.46e0.91) and BMLs (OR 0.60, 95% CI 0.37e0.97). Conclusions: Higher carotenoids intake and vegetable consumption were associated with reduced risk of hip cartilage defects and BMLs, and higher vitamin E intake was associated with reduced risk of hip cartilage defects. These findings suggest a beneficial effect of dietary antioxidants on hip joint health. Although our findings will need to be confirmed in longitudinal studies, they suggest that modification of dietary antioxidant intake may be one strategy for the prevention of hip osteoarthritis.
1). At the end of the experiment, aggrecan was 1.55-fold up-regulated while MMP-2 was 2.38-fold d... more 1). At the end of the experiment, aggrecan was 1.55-fold up-regulated while MMP-2 was 2.38-fold down-regulated (P < 0.05) (Fig. 1A). The histological appearance of the chondrocytes also showed load-dependency, with more hypercellularity and hypertrophy in the running group (Fig. 1B). FIB3-2 as a plasma biomarker, interacts with the tissue inhibitor of metalloproteinase 3 (TIMP-3) and the elevated amount of FIB3-2 is expected in osteoarthritis samples. FIB3-2 is also known to be cleaved by several MMPs family including MMP-2. FIB3-2 levels dropped in the running group (from 52.7 ± 13.2 nM to 30.2 ± 8.4 nM) as compared to the control group (45.3 ± 15.0 nM to 33.3 ± 9.7 nM) (Fig. 1C). MicroCT analysis revealed an enhancement in bone response as a result of early moderate physical training where epiphysis bone parameters in the running group including thickness and bone volume fraction of subchondral bone tibia plateau as well as trabecular bone mass significantly increased compared with control animals (Fig. 2). Conclusions: Gradual increase of running up to a moderate level to 1120 m/h for one hour enhances aggrecan expression, reduces catabolic enzymatic activity of MMP-2 as well as increases subchondral bone thickness in the epiphysis area and leads to hypercellularity and hypertrophy of the chondrocytes. Conclusively, a moderate exercise program can significantly influence both bone remodeling and cartilage tissue adaptation.
Botulinum toxin type-A (BTX-A) injections have become a common treatment modality for patients su... more Botulinum toxin type-A (BTX-A) injections have become a common treatment modality for patients suffering from muscle spasticity. Despite its benefits, BTX-A treatments have been associated with adverse effects on target muscles. Currently, application of BTX-A is largely based on clinical experience, and research quantifying muscle structure following BTX-A treatment has not been performed systematically. The purpose of this study was to evaluate strength, muscle mass, and contractile material six months following a single or repeated (2 and 3) BTX-A injections into the quadriceps femoris of New Zealand white rabbits. Twenty three skeletally mature rabbits were divided into four groups: experimental group rabbits received 1, 2, or 3 injections at intervals of 3 months (1-BTX-A, 2-BTX-A, 3-BTX-A, respectively) while control group rabbits received volume-matched saline injections. Knee extensor strength, quadriceps muscle mass, and quadriceps contractile material of the experimental group rabbits were expressed as a percentage change relative to the control group rabbits. One-way ANOVA was used to determine group differences in outcome measures (α=0.05). Muscle strength and contractile material were significantly reduced in experimental compared to control group rabbits but did not differ between Experimental groups. Muscle mass was the same in experimental BTX-A and control group rabbits. We concluded from these results that muscle strength and contractile material does not fully recover within six months of BTX-A treatment.
Objectives: Interactions between mechanical and non-mechanical independent risk factors for the o... more Objectives: Interactions between mechanical and non-mechanical independent risk factors for the onset and progression of Osteoarthritis (OA) are poorly understood. Therefore, the goal of the present study was to investigate the in vivo effects of muscle weakness, joint inflammation and the combination on the onset and progression of OA in a rabbit knee joint model. Materials and methods: Thirty 1-year-old female New Zealand White rabbits (average 5.7 kg, range 4.8e6.6 kg) were divided into four groups with one limb randomly assigned to be the experimental side: (1) surgical denervation of the vastus lateralis (VL) muscle; (2) muscle weakness induced by intramuscular injection of Botulinum toxin A (BTX-A); (3) intraarticular injection with Carrageenan to induce a transient inflammatory reaction; (4) combination of Carrageenan and BTX-A injection. After 90 days, cartilage histology of the articular surfaces were microscopically analyzed using the Osteoarthritis Research Society International (OARSI) histology scoring system. Results: VL denervation resulted in significantly higher OARSI scores in the patellofemoral joint (group 1). BTX-A administration resulted in significant cartilage damage in all four compartments of the knee (group 2). Carrageenan did not cause significant cartilage damage. BTX-A combined with Carrageenan lead to severe cartilage damage in all four compartments. Conclusion: Muscle weakness lead to significant OA in the rabbit knee. A transient local inflammatory stimulus did not promote cartilage degradation nor did it enhance OA progression when combined with muscle weakness. These results are surprising and add to the literature the conclusion that acute inflammation is probably not an independent risk factor for OA in this rabbit model.
Objective: Mesenchymal progenitor cells (MPCs) can differentiate into osteoblasts, adipocytes, an... more Objective: Mesenchymal progenitor cells (MPCs) can differentiate into osteoblasts, adipocytes, and chondrocytes, and are in part responsible for maintaining tissue integrity. Recently, a progenitor cell population has been found within the synovial fluid that shares many similarities with bone marrow MPCs. These synovial fluid MPCs (sfMPCs) share the ability to differentiate into bone and fat, with a bias for cartilage differentiation. In this study, sfMPCs were isolated from human and canine synovial fluid collected from normal individuals and those with osteoarthritis (human: clinician-diagnosed, canine: experimental) to compare the differentiation potential of CD90+ vs. CD902 sfMPCs, and to determine if CD90 (Thy-1) is a predictive marker of synovial fluid progenitors with chondrogenic capacity in vitro. Methods: sfMPCs were derived from synovial fluid from normal and OA knee joints. These cells were induced to differentiate into chondrocytes and analyzed using quantitative PCR, immunofluorescence, and electron microscopy. The CD90+ subpopulation of sfMPCs had increased chondrogenic potential compared to the CD902 population. Furthermore, sfMPCs derived from healthy joints did not require a micro-mass step for efficient chondrogenesis. Whereas sfMPCs from OA synovial fluid retain the ability to undergo chondrogenic differentiation, they require micro-mass culture conditions. Overall, this study has demonstrated an increased chondrogenic potential within the CD90+ fraction of human and canine sfMPCs and that this population of cells derived from healthy normal joints do not require a micro-mass step for efficient chondrogenesis, while sfMPCs obtained from OA knee joints do not differentiate efficiently into chondrocytes without the micro-mass procedure. These results reveal a fundamental shift in the chondrogenic ability of cells isolated from arthritic joint fluids, and we speculate that the mechanism behind this change of cell behavior is exposure to the altered milieu of the OA joint fluid, which will be examined in further studies.
International Journal of Molecular Sciences, Aug 11, 2021
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Clinical Orthopaedics and Related Research, Mar 1, 2007
We hypothesized specific growth factors are increased in the elbow capsules of patients with post... more We hypothesized specific growth factors are increased in the elbow capsules of patients with post traumatic elbow contractures. A model of surgically induced joint contracture in rabbit knees was developed to study the growth factor expression in joint contractures. This study demonstrates this model mimics the human condition and analyzes how the growth factor levels decrease with time in rabbit knees with contractures. Reverse transcription polymerase chain reaction was used to measure mRNA levels of transforming growth factor-β1, connective tissue growth factor, ED-A of fibronectin, and α-smooth muscle actin normalized to a housekeeping gene, glyceraldehyde-3phosphate dehydrogenase. In the joint capsules of patients with elbow contractures, mRNA levels were increased for transforming growth factor-β1, connective tissue growth factor, and α-smooth muscle actin. In the joint capsules of rabbit knees with contractures, mRNA levels were increased for transforming growth factor-β1, connective tissue growth factor, ED-A of fibronectin, and αsmooth muscle actin. The mRNA levels for transforming growth factor-β1, connective tissue growth factor, and α-smooth muscle actin decreased with time in rabbit knees. The elevated levels of these myofibroblast up-regulators and fibrogenic growth factors could explain the previously reported increase in myofibroblasts and collagen mRNA levels. The rabbit knee model correlated well with the human post traumatic elbow contractures. A sound anatomic basis for the pathogenesis of joint contractures is known. 9 For elbow joint contractures, surgical release has stressed the importance of removing the joint capsule. 5,30,34 There is an elevated number of myofibroblasts and an increase in the expression of αsmooth muscle actin (α-SMA), a myofibroblast marker, within joint capsules obtained from human elbows with chronic post traumatic contractures. 18 A rabbit model of post traumatic joint contractures has shown similar changes with regard to myofibroblast numbers and α-SMA levels in capsules obtained from knees with chronic contractures. 15 Thus, there is good correlation between the human condition and the animal model. The pathologic process that leads to increases in myofibroblast numbers and α-SMA levels detected in contracted joint capsules is unknown.
Background: Osteoarthritis (OA) is a chronic and painful condition where the articular cartilage ... more Background: Osteoarthritis (OA) is a chronic and painful condition where the articular cartilage surfaces progressively degenerate, resulting in loss of function and progressive disability. Obesity is a primary risk factor for the development and progression of knee OA, defined as the "metabolic OA" phenotype. Metabolic OA is associated with increased fat deposits that release inflammatory cytokines/adipokines, thereby resulting in systemic inflammation which can contribute to cartilage degeneration. There is currently no cure for OA. Prebiotics are a type of dietary fiber that can positively influence gut microbiota thereby reducing systemic inflammation and offering protection of joint integrity in rodents. However, no human clinical trials have tested the effects of prebiotics in adults with obesity suffering from knee OA. Therefore, the purpose of this double-blind, placebo-controlled, randomized trial is to determine if prebiotic supplementation can, through positive changes in the gut microbiota, improve knee function and physical performance in adults with obesity and knee OA. Methods: Adults (n = 60) with co-morbid obesity (BMI > 30 kg/m 2) and knee OA (Kellgren-Lawrence grade II-III) will be recruited from the Alberta Hip and Knee Clinic and the Rocky Mountain Health Clinic and surrounding community of Calgary, Canada, and randomized (stratified by sex, BMI, and age) to prebiotic (oligofructose-enriched inulin; 16 g/day) or a calorie-matched placebo (maltodextrin) for 6 months. Anthropometrics, performance-based tests, knee pain, serum inflammatory markers and metabolomics, quality of life, and gut microbiota will be assessed at baseline, 3 months, 6 months (end of prebiotic supplementation), and 3 months following the end of the prebiotic supplementation.
Mesenchymal stem cells (MSCs) derived from induced pluripotent stem cells (iPSCs) are a promising... more Mesenchymal stem cells (MSCs) derived from induced pluripotent stem cells (iPSCs) are a promising cell source for the repair of skeletal disorders. Recently, neural crest cells (NCCs) were reported to be effective for inducing mesenchymal progenitors, which have potential to differentiate into osteochondral lineages. Our aim was to investigate the feasibility of MSC-like cells originated from iPSCs via NCCs for osteochondral repair. Initially, MSC-like cells derived from iPSC-NCCs (iNCCs) were generated and characterized in vitro. These iNCC-derived MSC-like cells (iNCMSCs) exhibited a homogenous population and potential for osteochondral differentiation. No upregulation of pluripotent markers was detected during culture. Second, we implanted iNCMSC-derived tissue-engineered constructs into rat osteochondral defects without any preinduction for specific differentiation lineages. The implanted cells remained alive at the implanted site, whereas they failed to repair the defects, with only scarce development of osteochondral tissue in vivo. With regard to tumorigenesis, the implanted cells gradually disappeared and no malignant cells were detected throughout the 2-month follow-up. While this study did not show that iNCMSCs have efficacy for repair of osteochondral defects when implanted under undifferentiated conditions, iNCMSCs exhibited good chondrogenic potential in vitro under appropriate conditions. With further optimization, iNCMSCs may be a new source for tissue engineering of cartilage.
Adult mesenchymal stem cells were reported more than 30 years ago. Since then, their potential to... more Adult mesenchymal stem cells were reported more than 30 years ago. Since then, their potential to repair and regenerate damaged or diseased tissues has been studied intensively in both preclinical models and human trials. Most of the need for such tissue repair/regeneration is in older populations, so much of the effort has been performed with autologous cells in older patients. However, success has been difficult to achieve. In the literature, it has been noted that such progenitor cells from younger individuals often behave with more vigorous activity and are functionally enhanced compared to those from older individuals or animals. In addition, cells with the characteristics of mesenchymal stem cells or pluripotent mesenchymal regulatory cells exist in nearly all tissues and organs as pericytes since fetal life. Such evidence raises the possibility that one of the primary roles of these organ-specific cells is to regulate organ growth and maturation, and then subsequently play a ...
Sex-specific differences in biology and physiology likely start at the time of conception and pro... more Sex-specific differences in biology and physiology likely start at the time of conception and progress and mature during the pre-puberty time frame and then during the transitions accompanying puberty. These sex differences are impacted by both genetics and epigenetic alterations during the maturation process, likely for the purpose of preparing for successful reproduction. For females, later in life (~45–50) they undergo another transition leading to a loss of ovarian hormone production at menopause. The reasons for menopause are not clear, but for a subset of females, menopause is accompanied by an increased risk of a number of diseases or conditions that impact a variety of tissues. Most research has mainly focused on the target cells in each of the affected tissues rather than pursue the alternative option that there may be commonalities in the development of these post-menopausal conditions in addition to influences on specific target cells. This review will address some of the...
Journal of Biomedical Science and Engineering, 2021
Over 30 years ago, it was reported by Caplan that cells could be found in various adult tissues a... more Over 30 years ago, it was reported by Caplan that cells could be found in various adult tissues and fluids of a variety of species that could be induced in vitro to progress towards lineages such as chondrogenesis, osteogenesis and adipogenesis with different "cocktails" of reagents. These cells were called Mesenchymal Stem Cells (MSC) to reflect this pluripotency. After 30 years of intense research effort to directly use such cells for the repair or regeneration of damaged or injured tissues, the effort has met with limited in vivo success, but their use for in vitro tissue engineering has met with some success. This failure to live up to expectations for in vivo differentiation success has led Caplan to recently rename these cells Medicinal Signaling Cells (MSC) to reflect other abilities of these cells to secrete mediators and release exosomes containing biologically active molecules that can influence their neighboring cells in a paracrine manner. However, neither of these names completely captures the combined apparent in vivo functioning of MSC and their in vitro abilities to exhibit pluripotent behavior. Thus, it is suggested, based on the attributes of these cells and their tissue and clonal heterogeneity, that an alternative name be applied to these cells and they be described as Pluripotent Mesenchymal Regulatory Cells (PMRC). This name reflects their regulatory function as pericytes in tissues, as well as their well-known immunoregulatory activity when injected into the intra-articular space and their influence on activities such as
Objective/Hypothesis: A recent clinical study of the human lactoferrin peptide PXL01 in sodium hy... more Objective/Hypothesis: A recent clinical study of the human lactoferrin peptide PXL01 in sodium hyaluronate (HA) administrated around repaired tendons in the hand showed significantly improved digit mobility compared with placebo. To investigate the antiadhesive mechanisms of PXL01 in HA, we have used the rabbit lactoferrin peptide, rabPXL01 in HA, in a rabbit model of healing tendons and tendon sheaths. Materials and Methods: On days 1, 3, and 6 after tendon injury and surgical repair, reverse transcription-quantitative PCR (RT-qPCR) was used to assess messenger RNA (mRNA) expression levels for genes encoding the mucinous glycoprotein PRG4 (also called lubricin), and a subset of matrix proteins, cytokines, and growth factors involved in flexor tendon repair. RabPXL01 in HA was administrated locally around the repaired tendons, and the mRNA expression was compared with untreated repaired tendons and tendon sheaths using analysis of variance. Results: We observed, at all time points, ...
Background: Osteoarthritis is one of the leading causes of pain and disability worldwide, and a l... more Background: Osteoarthritis is one of the leading causes of pain and disability worldwide, and a large percentage of patients with osteoarthritis are individuals who are also obese. In recent years, a series of animal models have demonstrated that obesity-inducing diets can result in synovial joint damage (both with and without the superimposition of trauma), which may be related to changes in percentage of body fat and a series of low-level systemic inflammatory mediators. Of note, there is a disparity between whether the dietary challenges commence at weaning, representing a weanling onset, or at skeletal maturity, representing an adult onset of obesity. We wished to evaluate the effect of the dietary exposure time and the age at which animals are exposed to a high-fat and high-sucrose (HFS) diet to determine whether these factors may result in disparate outcomes, as there is evidence suggesting that these factors result in differential metabolic disturbances. Based on dietary exposure time, we hypothesized that rats fed an HFS diet for 14 weeks from weaning (HFS Weanling) would demonstrate an increase in knee joint damage scores, whereas rats exposed to the HFS diet for 4 weeks, starting at 12 weeks of age (HFS Adult) and rats exposed to a standard chow diet (Chow) would not display an increase in knee joint damage scores. Methods: Male Sprague-Dawley rats were fed either an HFS diet for 14 weeks from weaning (HFS Weanling) or an HFS diet for 4 weeks, starting at 12 weeks of age (HFS Adult). At sacrifice, joints were scored using the modified Mankin Criteria, and serum was analyzed for a defined subset of inflammatory markers (Interleukin-6, leptin, monocyte chemoattractant protein-1, and tumor necrosis factor a). Results: When the HFS Weanling and HFS Adult groups were compared, both groups had a similar percent of body fat, although the HFS Weanling group had a significantly greater body mass than the HFS Adult group. The HFS Weanling and HFS Adult animals had a significant increase in body mass and percentage of body fat when compared to the Chow group. Although knee joint damage scores were low in all 3 groups, we found, contrary to our hypothesis, that the HFS Adult group had statistically significant greater knee joint damage scores than the Chow and HFS Weanling groups. Furthermore, we observed that the HFS Weanling group did not have significant differences in knee joint damage scores relative to the Chow group. Conclusion: These findings indicate that the HFS Weanling animals were better able to cope with the dietary challenge of an HFS diet than the HFS Adult group. Interestingly, when assessing various serum proinflammatory markers, no significant differences were detected between the HFS Adult and HFS Weanling groups. Although details regarding the mechanisms underlying an increase in knee joint damage scores in the HFS Adult group remain to be elucidated, these findings indicate that dietary exposure time maybe less important than the age at which an HFS diet is introduced. Moreover, increases in serum proinflammatory mediators do not appear to be directly linked to knee joint damage scores in the HFS Weanling group animals but may be partially responsible for the observed knee joint damage in the adults over the very short time of exposure to the HFS diet.
The role of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) has been highl... more The role of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) has been highlighted in mechanisms underlying inflammatory and neuropathic pain processes. The present study was designed to investigate whether NF-κB signaling is associated with pain-related neuropeptide expression in patients with chronic back pain related to degenerative disc disease (DDD). Intervertebral disc (IVD) tissues were collected from forty DDD patients undergoing disc replacement or fusion surgery, and from eighteen postmortem (PM) control subjects. RELA, NFKB1, CGRP, TAC1, TRPV1, and MMP-3 gene expression were analyzed by RT-qPCR, while NF-κB subunit RelA and NF-κB1–DNA binding in nuclear extracts and calcitonin gene related peptide (CGRP), substance P (SP), and transient receptor potential, subfamily V, member 1 (TRPV1) protein levels in cytosolic extracts of tissues were assessed by enzyme-linked immunosorbent assay (ELISA). An upregulated NF-κB1–DNA binding, and higher CGRP and TRPV1...
objective measures, such as timed walks or sit-to-stand tests. Such objective measures are admini... more objective measures, such as timed walks or sit-to-stand tests. Such objective measures are administered in controlled, laboratory style settings, and may not reflect levels of activity in daily life. With the rapid development of monitoring technology, there is opportunity to characterise the relationship between PROMs and behaviour in a natural setting and to develop methods of passive monitoring of outcome and recovery after surgery. We are working with a multidisciplinary team which has developed a system of low powered sensors that can monitor the health-related behaviours of people living at home. The system includes: sensors for the home environment (measuring temperature, humidity, room occupancy, water and electricity usage) a wrist-band body-worn activity monitor and silhouette (body outline) sensors. The SPHERE system of sensors is now being installed in 100 homes belonging to the general population. Within this cohort we are installing the system in the homes of 20 patients who are about to undergo a total hip or knee replacement (THR/TKR). The study aims to: (a) determine to what extent the sensory data obtained from the SPHERE system is comparable to data obtained from routine clinical measures and PROMs in the assessment of patients' activity, function and recovery processes; (b) investigate whether the sensory data can detect meaningful changes in recovery. Methods: To assess the accuracy and usefulness of the sensory data, in this 1-year observational study, patients will be provided with the sensor system to monitor and record daily continuous measurements. We will make and refine appropriate data learning outcomes with the quantitative data e.g., daily measurements in the weeks parallel to the distribution of PROM assessments pre/post-operative (4e9 days, 6 and 12 weeks) and weekly measurements during the other months. The study will assess the relationships between environmental, behavioural and movement data and the parameters of interest from the PROMs assessments over time. Interviews and focus groups with patients and health professional will provide qualitative data and achieve depth in understanding the accuracy of the data, its usefulness for health professionals in decision making, and if the technology is acceptable. Results: The SPHERE sensor system has been installed in the homes of two patients. We aim to recruit up to 20 patients, (aged 18 years or over) whom are due to undergo a TKR or THR in the UK. Conclusions: This study will provide a unique understanding of home and wearable sensor technology in an orthopaedic population and will compare sensor data with current PROMs.
Obesity, and associated metabolic syndrome, have been identified as primary risk factors for the ... more Obesity, and associated metabolic syndrome, have been identified as primary risk factors for the development of knee osteoarthritis (OA), representing nearly 60% of the OA patient population. In this study, we sought to determine the effects of prebiotic fibre supplementation, aerobic exercise, and the combination of the two interventions, on the development of metabolic knee osteoarthritis in a high-fat/high-sucrose (HFS) diet-induced rat model of obesity. Twelve-week-old male Sprague-Dawley rats were randomized into five groups: a non-exercising control group fed a standard chow diet, a non-exercising group fed a HFS diet, a non-exercising group fed a HFS diet combined with prebiotic fibre supplement, an exercise group fed a HFS diet, and an exercise group fed a HFS diet combined with prebiotic fibre supplement. Outcome measures included knee joint damage, percent body fat, insulin sensitivity, serum lipid profile, serum endotoxin, serum and synovial fluid cytokines and adipokines...
associated with a reduced prevalence of femoral head cartilage defects (OR 0.65, 95% CI 0.46e0.91... more associated with a reduced prevalence of femoral head cartilage defects (OR 0.65, 95% CI 0.46e0.91) and BMLs (OR 0.60, 95% CI 0.37e0.97). Conclusions: Higher carotenoids intake and vegetable consumption were associated with reduced risk of hip cartilage defects and BMLs, and higher vitamin E intake was associated with reduced risk of hip cartilage defects. These findings suggest a beneficial effect of dietary antioxidants on hip joint health. Although our findings will need to be confirmed in longitudinal studies, they suggest that modification of dietary antioxidant intake may be one strategy for the prevention of hip osteoarthritis.
1). At the end of the experiment, aggrecan was 1.55-fold up-regulated while MMP-2 was 2.38-fold d... more 1). At the end of the experiment, aggrecan was 1.55-fold up-regulated while MMP-2 was 2.38-fold down-regulated (P < 0.05) (Fig. 1A). The histological appearance of the chondrocytes also showed load-dependency, with more hypercellularity and hypertrophy in the running group (Fig. 1B). FIB3-2 as a plasma biomarker, interacts with the tissue inhibitor of metalloproteinase 3 (TIMP-3) and the elevated amount of FIB3-2 is expected in osteoarthritis samples. FIB3-2 is also known to be cleaved by several MMPs family including MMP-2. FIB3-2 levels dropped in the running group (from 52.7 ± 13.2 nM to 30.2 ± 8.4 nM) as compared to the control group (45.3 ± 15.0 nM to 33.3 ± 9.7 nM) (Fig. 1C). MicroCT analysis revealed an enhancement in bone response as a result of early moderate physical training where epiphysis bone parameters in the running group including thickness and bone volume fraction of subchondral bone tibia plateau as well as trabecular bone mass significantly increased compared with control animals (Fig. 2). Conclusions: Gradual increase of running up to a moderate level to 1120 m/h for one hour enhances aggrecan expression, reduces catabolic enzymatic activity of MMP-2 as well as increases subchondral bone thickness in the epiphysis area and leads to hypercellularity and hypertrophy of the chondrocytes. Conclusively, a moderate exercise program can significantly influence both bone remodeling and cartilage tissue adaptation.
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Papers by David A Hart