Variants within the MMP3 gene are associated with achilles tendinopathy: possible interaction with the COL5A1 gene

Objectives: Sequence variation within the COL5A1 and TNC genes are known to associate with Achilles tendinopathy. The primary aim of this case-control genetic association study was to investigate whether variants within the matrix metalloproteinase 3 (MMP3) gene also contributed to both Achilles tendinopathy and Achilles tendon rupture in a Caucasian population. A secondary aim was to establish whether variants within the MMP3 gene interacted with the COL5A1 rs12722 variant to raise risk of these pathologies. Methods: 114 subjects with symptoms of Achilles tendon pathology and 98 healthy controls were genotyped for MMP3 variants rs679620, rs591058 and rs650108. Results: As single markers, significant associations were found between the GG genotype of rs679620 (OR = 2.5, 95% CI 1.2 to 4.90, p = 0.010), the CC genotype of rs591058 (OR = 2.3, 95% CI 1.1 to 4.50, p = 0.023) and the AA genotype of rs650108 (OR = 4.9, 95% CI 1.0 to 24.1, p = 0.043) and risk of Achilles tendinopathy. The ATG haplotype (rs679620, rs591058, and rs650108) was under-represented in the tendinopathy group when compared to the control group (41% vs 53%, p = 0.038). Finally, the G allele of rs679620 and the T allele of COL5A1 rs12722 significantly interacted to raise risk of AT (p = 0.006). No associations were found between any of the MMP3 markers and Achilles tendon rupture. Conclusion: Variants within the MMP3 gene are associated with Achilles tendinopathy. Furthermore, the MMP3 gene variant rs679620 and the COL5A1 marker rs12722 interact to modify the risk of tendinopathy. These data further support a genetic contribution to a common sports related injur

TIMP2 and GDF-5 gene variants and achilles tendon pathology: replication study in a British case-control population

Introduction: Achilles tendon pathology (ATP) encompasses a range of tendon overuse injuries that can be sub-classified into separate pathologies [Weinfeld, 2014]. To date, a number of single nucleotide polymorphisms (SNPs) have been associated with ATP [Raleigh and Collins, 2012] but, with the exception of the COL5A1 rs12722 variant, limited work has been published on attempting to replicate these findings in cohorts other than those recruited from either South Africa or Australia. We selected variants within the TIMP2 (rs4789932) and GDF-5 (rs143383) genes, that have previously been shown to associate with ATP [El Khoury et al, 2013 and Posthumus et al, 2010], and attempted to replicate previous associations in a newly recruited British-based, case-control, Caucasian cohort. Methods: We recruited 133 ATP Caucasian patients from the County Clinic in Northampton along with 131 physically active controls from various sports clubs within the East Midlands region. DNA samples were collected from saliva (DNA genotek Ltd) and Taqman technology, using allele specific probes and primers, was used to genotype all DNA samples. Reactions were run on a StepOne Plus real-time PCR instrument (ABI). Genotypes were called according to post run cluster profiles and data were analysed using Chi-squared (c2) analysis or Fisher’s exact test. Significance was accepted at p < 0.05. All procedures were approved by the University of Northampton Research Ethics Committee. Results: For the TIMP2 rs4789932 variant we found no association between genotype and case or control status in the entire cohort (p = 0.279). However, in sex specific analysis we did find that the CC genotype was associated (p = 0.043) with male ATP cases compared to controls (Table 1). For the GDF-5 rs143383 variant, we found no association between genotype and case or control status in the entire cohort (p = 0.538) or in either male (p = 0.319) or female (p = 0.737) specific analysis (data not shown). Genotypes did not associate with any other potential confounding variables. Conclusions: The TIMP2 rs478992 CC genotype was associated with male cases of ATP. Although this locus was previously associated with ATP in cohorts recruited from the Southern Hemisphere it was the CT genotype that was the risk factor and the association was not sex specific [El Khoury et al, 2013]. This result might be related to differences in unknown environmental exposures between the cohorts investigated that may modify the effect of the genotype. We found no evidence of an association between ATP and the GDF-5 variant. These data should be viewed as preliminary findings and will need to be repeated in a larger cohort

MMP3 and TIMP2 gene variants as predisposing factors for Achilles tendon pathologies: attempted replication study in a British case–control cohort

Variants within the MMP3 (rs679620) and TIMP2 (rs4789932) genes have been associated with the risk of Achilles tendon pathology (ATP) in populations from South Africa and Australia. This study aimed to determine whether these variants were associated with the risk of ATP in British Caucasians. We recruited 118 cases with ATP, including a subset of 25 individuals with Achilles tendon rupture (RUP) and 131 controls. DNA samples were isolated from saliva and genotyped using qPCR. For the TIMP2 rs4789932 variant we found a significant (p = 0.038) difference in the genotype distribution frequency between males with ATP (CC, 39.4%; CT, 43.7%; TT, 16.9%) compared to male controls (CC, 20.7%; CT, 59.8%; TT, 19.5%). We also observed a difference in the TIMP2 rs4789932 genotype distribution between males with rupture compared to male controls (p = 0.038). The MMP3 rs679620 GG genotype was found to be overrepresented in the Achilles tendon rupture (RUP) group (AA, 24.0%; AG, 32.0%; GG, 44.0%) compared to controls (AA, 26.7%; AG, 54.2%; GG, 19.1%). In conclusion, the CT genotype of the TIMP2 rs4789932 variant was associated with lower risk of ATP in males. Furthermore, while we revealed differences for both variants in genotype distribution between the RUP and control groups, the sample size of the RUP group was small and confirmation would be required in additional cohorts. Finally, although both the TIMP2 rs4789932 and MMP3 rs679620 variants tentatively associated with ATP, there were differences in the direction of association compared to earlier work

Human genetic variation, Sport and Exercise Medicine, and Achilles tendinopathy: role for angiogenesis-associated genes

Sport and Exercise Medicine is one of the important subspecialties of 21st century healthcare contributing to improving the physical function, health, and vitality of populations while reducing the prevalence of lifestyle-related diseases. Moreover, sport and exercise are associated with injuries such as Achilles tendinopathy, which is a common tendon injury. The angiogenesis-associated signaling pathway plays a key role in extracellular matrix remodeling, with increased levels of angiogenic cytokines reported after cyclic stretching of tendon fibroblasts. We investigated the variants in angiogenesis genes in relation to the risk of Achilles tendinopathy in two population samples drawn independently from South Africa (SA) and the United Kingdom (UK). The study sample comprised 120 SA and 130 UK healthy controls, and 108 SA and 87 UK participants with Achilles tendinopathy. All participants were genotyped for five functional polymorphisms in the vascular endothelial growth factor, A isoform (VEGFA) (rs699947, rs1570360, rs2010963) and kinase insert-domain receptor (KDR) genes (rs1870377, rs2071559). The VEGFA A-G-G inferred haplotype was associated with an increased risk of Achilles tendinopathy in the SA group (15% in controls vs. 20% in cases, p = 0.048) and the combined SA+UK group (14% in controls vs. 20% in cases, p = 0.009). These new findings implicate the VEGFA gene with Achilles tendinopathy risk, while highlighting the potential biological significance of the angiogenesis signaling pathway in the etiology of Achilles tendinopathy. The evidence suggesting a genetic contribution to the susceptibility of sustaining a tendon injury is growing. We anticipate that high-throughput and multi-omics approaches, building on genomics, proteomics, and metabolomics, may soon uncover the pathophysiology of many diseases in the field of Sports and Exercise Medicine, as a new frontier of global precision medicine

Polymorphisms within the COL5A1 gene and regulators of the extracellular matrix modify the risk of Achilles tendon pathology in a British case control study

Several genetic loci have been associated with risk of Achilles tendon pathology (ATP) within South African and Australian populations. The aim of this study was, therefore, to evaluate eight previously implicated genetic variants in an independent British population. A total of 130 asymptomatic controls (CON) and 112 participants clinically diagnosed with ATP comprising 87 individuals with chronic Achilles tendinopathy (TEN) and 25 with Achilles tendon ruptures (RUP) were included. All participants were genotyped for variants within the COL5A1, MIR608, IL-1β, IL-6 and CASP8 genes. Primary findings implicated COL5A1 and CASP8. Three inferred allele combinations constructed from COL5A1 rs12722, rs3196378 and rs71746744 were identified as risk modifiers. The T–C–D combination was associated with increased risk of ATP (P = 0.023) and RUP (P < 0.001), the C–A–I combination was associated with increased risk of ATP (P = 0.011), TEN (P = 0.011) and RUP (P = 0.011) and the C–C–D combination was associated with decreased risk of ATP (P = 0.011) and RUP (P = 0.004). The CASP8 rs3834129 DD genotype was associated with decreased risk of TEN (P = 0.020, odds ratio: 0.45, 95% confidence interval: 0.22–0.90) and the CASP8 I–G (rs3834129–rs1045485) inferred allele combination was associated with increased risk of TEN (P = 0.031). This study further highlights the importance of polymorphisms within COL5A1 and CASP8 in the aetiology of ATP

Variation within three apoptosis associated genes as potential risk factors for Achilles tendinopathy in a British based case-control cohort

Achilles tendon pathology (ATP) is a degenerative condition which exhibits excessive tenocyte apoptosis. Tumour necrosis factor receptor 1 (TNFR1), caspase-3 (CASP3) and caspase-8 (CASP8) are important regulators of apoptosis. To date, the effect of variation within the genes for TNFR1 and CASP3 as risk factors for ATP have not been described. There is evidence that two single nucleotide polymorphisms (SNPs) within the CASP8 gene are associated with ATP, but only in populations from the Southern Hemisphere. The primary aim of this study was to determine whether SNPs within the TNFRSF1A and CASP3 genes were associated with ATP in British Caucasians. We additionally sought to determine whether copy number variation (CNV) within the CASP8 gene was associated with ATP. We recruited 262 (131 ATP cases and 131 asymptomatic controls) Caucasian participants for this genetic association study and used quantitative PCR with chi-squared (χ2) tests and ANOVA to detect significant associations. We found no association between the TNFRSF1A rs4149577 (p = 0.561), CASP3 rs1049253 (p = 0.643) and CASP8 copy number variants (p = 0.219) and ATP. Likewise, when we tested potential interactions between gender, genotype and the risk of ATP, we found no association with the variants investigated. In conclusion, the TNFRSF1A, CASP3 and CASP8 gene variants were not associated with ATP in British Caucasians

Association of ACTN3 R577X but not ACE I/D gene variants with elite rugby union player status and playing position

We aimed to quantify the ACE I/D and ACTN3 R577X (rs1815739) genetic variants in elite rugby athletes (rugby union and league), compare genotype frequencies to controls and between playing positions. The rugby athlete cohort consisted of 507 Caucasian men, including 431 rugby union athletes that for some analyses were divided into backs and forwards and into specific positional groups: front five, back row, half backs, centers and back three. Controls were 710 Caucasian men and women. Real-time PCR of genomic DNA was used to determine genotypes using TaqMan probes and groups were compared using Chi-square and odds ratio (OR) statistics. Correction of p-values for multiple comparisons was according to Benjamini-Hochberg. There was no difference in ACE I/D genotype between groups. ACTN3 XX genotype tended to be underrepresented in rugby union backs (15.7%) compared to forwards (24.8%; P=0.06). Interestingly, the 69 back three players (wings and full backs) in rugby union included only six XX genotype individuals (8.7%), with the R allele more common in the back three (68.8%) than controls (58.0%; χ2=6.672, P=0.04; OR=1.60) and forwards (47.5%; χ2=11.768, P=0.01; OR=2.00). Association of ACTN3 R577X with playing position in elite rugby union athletes suggests inherited fatigue resistance is more prevalent in forwards while inherited sprint ability is more prevalent in backs, especially wings and full backs. These results also demonstrate the advantage of focusing genetic studies on a large cohort within a single sport, especially when intra-sport positional differences exist, instead of combining several sports with varied demands and athlete characteristics

Vitamin D and Foot and Ankle Trauma: An individual or societal problem?

Background Vitamin D deficiency is a worldwide health concern. Hypovitaminosis D may adversely affect recovery from bone injury. The authors aimed to perform an audit of the Vitamin D status of patients in three centres in the United Kingdom presenting with foot and ankle osseous damage. Methods Serum 25-hydroxyvitamin-D (vitamin D) levels were obtained in patients presenting with imaging confirmed foot and ankle osseous trauma. Variables including age, gender, ethnicity, location, season, month, anatomical location and type of bone injury were recorded. Results 308 patients were included from three different centres. 66.6% were female. The average age was 47.7 (range; 10–85). The mean hydroxyvitamin-D levels were 52.0 nmol/L (SD 28.5). 18.8% were grossly deficient, 23.7% deficient, 34.7% insufficient and 22.7% within normal range. 351 separate bone injuries were identified of which 104 were categorised as stress reactions, 134 as stress fractures, 105 as fractures and 8 non-unions. Age, gender, anatomical location and fracture type did not statistically affect vitamin D levels. Ethnicity did affect Vitamin D levels: non-Caucasians mean levels were 32.4 nmols/L compared to Caucasian levels of 53.2 nmol/L (p = 0.0026). Conclusion Only 18.8% of our trauma patients had a normal Vitamin D level and 22.7% were grossly deficient. Patient age, gender, anatomical location and injury type did not statistically affect vitamin D levels. No difference between trauma and elective patients were found. Hypovitaminosis D is a problem of society in general rather than specific to certain foot and ankle injury patterns or particular patient groups sustaining trauma. Level of evidence 2b

Tendon and Ligament Genetics: How Do They Contribute to Disease and Injury? A Narrative Review

A significant proportion of patients requiring musculoskeletal management present with tendon and ligament pathology. Our understanding of the intrinsic and extrinsic mechanisms that lead to such disabilities is increasing. However, the complexity underpinning these interactive multifactorial elements is still not fully characterised. Evidence highlighting the genetic components, either reducing or increasing susceptibility to injury, is increasing. This review examines the present understanding of the role genetic variations contribute to tendon and ligament injury risk. It examines the different elements of tendon and ligament structure and considers our knowledge of genetic influence on form, function, ability to withstand load, and undertake repair or regeneration. The role of epigenetic factors in modifying gene expression in these structures is also explored. It considers the challenges to interpreting present knowledge, the requirements, and likely pathways for future research, and whether such information has reached the point of clinical utility

First metatarsophalangeal joint arthrodesis using a vitallium plate with a mean two year follow up

Twenty-four patients (33 feet) underwent metatarsophalangeal joint arthrodesis using a vitallium plate with an additional oblique screw. The mean age was 55 years (range, 37–68) with a mean follow up of 28 months (range, 16–45). Patients were evaluated using the American Foot and Ankle Society clinical and radiographic guidelines. Twenty-three patients (32 feet) went on to complete fusion within 12 weeks, one patient had a non-union, the fusion was repeated successfully. One patient had deep infection and two patients had persistent foot pain. Hallux valgus angle was reduced by a mean of 12 degrees and intermetatarsal angle by a mean of 2 degrees. Patient satisfaction was high with relief of symptoms and improved appearance of the foot. First metatarsophalangeal joint arthrodesis using a vitallium plate with an oblique interfragmentary screw is a successful procedure with a high fusion rate, low complication rate and a high level of patient satisfactio