Genetics of osteoarthritis.

Osteoarthritis genetics has been transformed in the past decade through the application of large-scale genome-wide association scans. So far, over 100 polymorphic DNA variants have been associated with this common and complex disease. These genetic risk variants account for over 20% of osteoarthritis heritability and the vast majority map to non-protein coding regions of the genome where they are presumed to act by regulating the expression of target genes. Statistical fine mapping, in silico analyses of genomics data, and laboratory-based functional studies have enabled the identification of some of these targets, which encode proteins with diverse roles, including extracellular signaling molecules, intracellular enzymes, transcription factors, and cytoskeletal proteins. A large number of the risk variants correlate with epigenetic factors, in particular cartilage DNA methylation changes in cis, implying that epigenetics may be a conduit through which genetic effects on gene expression are mediated. Some of the variants also appear to have been selected as humans adapted to bipedalism, suggesting that a proportion of osteoarthritis genetic susceptibility results from antagonistic pleiotropy, with risk variants having a positive role in joint formation but a negative role in the long-term health of the joint. Although data from an osteoarthritis genetic study has not yet directly led to a novel treatment, some of the osteoarthritis associated genes code for proteins that have available therapeutics. Genetic investigations are therefore revealing fascinating fundamental insights into osteoarthritis and can expose options for translational intervention.

Multi-tissue epigenetic analysis of the osteoarthritis susceptibility locus mapping to the plectin gene PLEC.

OBJECTIVE: In cartilage, the osteoarthritis (OA) associated single nucleotide polymorphism (SNP) rs11780978 correlates with differential expression of PLEC, and with differential methylation of PLEC CpG dinucleotides, forming eQTLs and mQTLs respectively. This implies that methylation links chondrocyte genotype and phenotype, thus driving the functional effect of this genetic risk signal. PLEC encodes plectin, a cytoskeletal protein that enables tissues to respond to mechanical forces. We sought to assess whether these PLEC functional effects were cartilage specific. METHOD: Cartilage, fat pad, synovium and peripheral blood were collected from patients undergoing arthroplasty. PLEC CpGs were analysed for mQTLs and allelic expression imbalance (AEI) was performed to test for eQTLs. Plectin was knocked down in a mesenchymal stem cell (MSC) line using CRISPR/Cas9 and cells phenotyped by RNA-sequencing. RESULTS: mQTLs were discovered in fat pad, synovium and blood. Their effects were however stronger in the joint tissues and of comparable effect between these tissues. We observed AEI in synovium in the same direction as for cartilage and correlations between methylation and PLEC expression. Knocking-down plectin impacted on pathways reported to have a role in OA, including Wnt signalling, glycosaminoglycan biosynthesis and immune regulation. CONCLUSIONS: Synovium is also a target of the rs11780978 OA association functionally operating on PLEC. In fat pad, mQTLs were identified but these did not correlate with PLEC expression, suggesting the functional effect is not joint-wide. Our study highlights interplay between genetic risk, DNA methylation and gene expression in OA, and reveals clear differences between tissues from the same diseased joint.

Discovery and analysis of methylation quantitative trait loci (mQTLs) mapping to novel osteoarthritis genetic risk signals.

OBJECTIVE: Osteoarthritis (OA) is polygenic with over 90 independent genome-wide association loci so far reported. A key next step is the identification of target genes and the molecular mechanisms through which this genetic risk operates. The majority of OA risk-conferring alleles are predicted to act by modulating gene expression. DNA methylation at CpG dinucleotides may be a functional conduit through which this occurs and is detectable by mapping methylation quantitative trait loci, or mQTLs. This approach can therefore provide functional insight into OA risk and will prioritize genes for subsequent investigation. That was our goal, with a focus on the largest set of OA loci yet to be reported. METHOD: We investigated DNA methylation, genotype and RNA sequencing data derived from the cartilage of patients who had undergone arthroplasty and combined this with in silico analyses of expression quantitative trait loci, epigenomes and chromatin interactions. RESULTS: We investigated 42 OA risk loci and in ten of these we identified 24 CpGs in which methylation correlated with genotype (false discovery rate (FDR) P-values ranging from 0.049 to 1.73x10-25). In silico analyses of these mQTLs prioritised genes and regulatory elements at the majority of the ten loci, with COLGALT2 (encoding a collagen galactosyltransferase), COL11A2 (encoding a polypeptide chain of type XI collagen) and WWP2 (encoding a ubiquitin ligase active during chondrogenesis) emerging as particularly compelling target genes. CONCLUSION: We have highlighted the pivotal role of DNA methylation as a link between genetic risk and OA and prioritized genes for further investigation.

Acupuncture and other physical treatments for the relief of pain due to osteoarthritis of the knee: network meta-analysis.

OBJECTIVE: To compare the effectiveness of acupuncture with other relevant physical treatments for alleviating pain due to knee osteoarthritis. DESIGN: Systematic review with network meta-analysis, to allow comparison of treatments within a coherent framework. Comprehensive searches were undertaken up to January 2013 to identify randomised controlled trials in patients with osteoarthritis of the knee, which reported pain. RESULTS: Of 156 eligible studies, 114 trials (covering 22 treatments and 9,709 patients) provided data suitable for analysis. Most trials studied short-term effects and many were classed as being of poor quality with high risk of bias, commonly associated with lack of blinding (which was sometimes impossible to achieve). End of treatment results showed that eight interventions: interferential therapy, acupuncture, TENS, pulsed electrical stimulation, balneotherapy, aerobic exercise, sham acupuncture, and muscle-strengthening exercise produced a statistically significant reduction in pain when compared with standard care. In a sensitivity analysis of satisfactory and good quality studies, most studies were of acupuncture (11 trials) or muscle-strengthening exercise (9 trials); both interventions were statistically significantly better than standard care, with acupuncture being statistically significantly better than muscle-strengthening exercise (standardised mean difference: 0.49, 95% credible interval 0.00-0.98). CONCLUSIONS: As a summary of the current available research, the network meta-analysis results indicate that acupuncture can be considered as one of the more effective physical treatments for alleviating osteoarthritis knee pain in the short-term. However, much of the evidence in this area of research is of poor quality, meaning there is uncertainty about the efficacy of many physical treatments.

A placebo-controlled phase I/II study of adefovir dipivoxil in patients with chronic hepatitis B virus infection.

Adefovir dipivoxil (bis-POM PMEA) is an adenine nucleotide analogue with activity against retroviruses and herpesviruses, and in vitro activity against hepatitis B virus (HBV). This study was conducted to evaluate its safety and antiviral activity in patients with chronic HBV infection. Twenty patients (13 co-infected with human immunodeficiency virus, HIV) were randomized in a phase I/II, double-blind, placebo-controlled study. Patients who had been hepatitis B surface antigen (HBsAg)/hepatitis B e antigen (HBeAg) positive for > or = 6 months, with elevated hepatic transaminases and serum HBV DNA > or = 50 pg ml-1, were randomized to adefovir dipivoxil 125 mg (n = 15) or placebo (n = 5) as a single, daily, oral dose for 28 days. Antiviral activity was assessed by changes in serum HBV DNA (using the Digene Hybrid Capture assay) and HBeAg/hepatitis B e antibody (HBeAb) status. HBV DNA levels fell rapidly by > 1 log10 in all active drug recipients (median fall 1.8 log10 pg ml-1) but increased by 0.01 log10 pg ml-1 in controls (P = 0.002). Reductions were sustained during treatment. HBV DNA returned to baseline over 1-6 weeks following discontinuation of active drug. HBeAg became transiently undetectable in one patient on treatment and, in another, sustained seroconversion to HBeAb occurred 12 weeks after treatment ended. Liver transaminase elevations > 300 U l-1 were observed in three patients during therapy (leading to protocol-specified treatment discontinuation or dose reduction) and in four patients during follow-up. On-treatment transaminase elevations were associated with HIV status, occurring in three of six HIV-uninfected patients compared with none of nine who were HIV infected. In addition, a slower return to baseline of serum HBV DNA levels was observed in the non-HIV-infected patients. Treatment for chronic hepatitis B as a once-daily oral dose was well tolerated and associated with significant and sustained reductions in serum HBV DNA levels during treatment. Transaminase elevations, which may be related to the therapeutic effect, were observed during and after treatment. Further studies are warranted to investigate the safety, and optimum dose and duration, of adefovir dipivoxil treatment for chronic hepatitis B.

Pathfinders: a self-care and health education program for older widows and widowers.

Recent studies suggest that the loss of a spouse can be disruptive to the survivor's self-care and health promotion practices, especially for those who lack the knowledge and skills to successfully engage in these behaviors. Pathfinders is a theoretically and research-based self-care and health education program for recently widowed persons aged 50 and older. This article describes the program's structure, content, and recruitment methods. Preliminary evaluation data suggest that the program is achieving many of the intended outcomes. Issues pertaining to replication as well as limitations are discussed.

Ion, water and neutral solute transport in Xenopus oocytes expressing frog lens MIP.

We have expressed frog (Rana pipiens) lens major intrinsic protein (MIP) in Xenopus oocytes and observed its effect on ion conductance, water permeability and neutral solute transport. SDS-PAGE and immunoblotting demonstrated oocytes injected with MIP mRNA expressed the protein at high levels. Immunolocalization indicated the expressed MIP migrated to the plasma membrane. MIP had no effect on the slope of oocyte I-V relations in the range -50 to +10 mV, although the averaged I-V curve was shifted 10 mV positive to control. MIP increased oocyte water permeability by a factor of 1.9 +/- 0.2, whereas the permeability to sucrose, 2-deoxyglucose, inositol, sorbitol, reduced glutathione or urea was unchanged. Glycerol permeability was enhanced in oocytes expressing MIP. In contrast to control oocytes, 3H-glycerol radioactivity accumulation did not follow first order kinetics. Radioactivity continued to accumulate even after 19 h of uptake and went beyond equilibrium with the bath. The time course of MIP-mediated glycerol uptake was modeled assuming metabolic trapping with good results. Based on this model, MIP increased oocyte glycerol permeability by a factor of 2.7.

The cDNA sequence encoding the major intrinsic protein of frog lens.

A cDNA clone encoding the frog lens major intrinsic protein (MIP) has been isolated and sequenced. The predicted protein of 28 kDa has high sequence identity and similarity to mammalian and avian lens MIP sequences. Frog lens MIP is encoded by a transcript of 4.4 kb.

Thoracoscopic carbon dioxide laser treatment of bullous emphysema.

A new technique of thoracoscopic laser ablation of pulmonary bullae suitable for patients with multiple bullae and diffuse emphysema was developed and assessed in 22 patients. 20 of 22 patients survived. Pre-operative and postoperative functional evaluation is available for the 11 patients followed up for more than a month; at 1 to 3 months postoperatively there were increases in FVC (mean 2.0 litres pre-operatively to 2.7 litres postoperatively, p less than 0.001), in FEV1 (0.74 to 1.06 litres, p = 0.01), and in maximum exercise treadmill times (5.4 min to 8.0 min, p less than 0.01). Postoperative air leaks lasted a mean of 13 days and usually resolved spontaneously. Other complications were bleeding (1 patient) and unilateral acute lung injury (1 patient). These results suggest that selected patients with diffuse emphysema and pulmonary bullae may benefit from thoracoscopic carbon dioxide laser ablation.

HIV infection due to a platelet transfusion after allogeneic bone marrow transplantation.

A 30-yr-old man with chronic granulocytic leukaemia received a bone marrow transplant from his histocompatible sister in December 1982. His post-transplant course was complicated by Grade III graft-versus-host disease and multiple infectious episodes until his death from pneumonia on d + 190. He was later found to be seropositive for anti-HIV at the time of his death. Retrospective analysis of stored sera showed a transient period of seropositivity from d + 11 to d + 20 thought to reflect passive transfer of antibody from a blood product transfused prior to d + 11 when he was also exposed to infectious virus. He remained seronegative until d + 78 when anti-HIV was again found. Seropositivity persisted until his death and was attributed to endogenous antibody response. Although it is unclear whether his clinical course was due to AIDS, exposure of an immunosuppressed patient to HIV may be associated with more rapid development of clinical disease.

Late-onset hemorrhagic cystitis associated with urinary excretion of polyomaviruses after bone marrow transplantation.

Hemorrhagic cystitis is a well known complication of allogeneic bone marrow transplantation (BMT) and is normally attributed to the use of high-dose cyclophosphamide in the preparative regimen. Hemorrhagic cystitis occurring late after BMT is unlikely to be due to the effects of this conditioning, and probably has an infective etiology. Three patients undergoing BMT for chronic granulocytic leukemia (CGL) developed terminal dysuria and hematuria at 38, 56, and 149 days post-BMT. Electron microscopy (EM) of urine voided at these times revealed large numbers of papovavirions, which were subsequently identified as BK virus. Urine samples inoculated onto human embryonic lung fibroblasts induced infection of the cells and replication of the virus as detected by EM of tissue culture fluid. Urine from one of these patients was examined by standard cytological techniques, and EM of urothelial cells showed nuclear inclusions consisting of nonencapsulated virus particles of diameter 40 nm, consistent with papovavirus. Five further patients were found to be excreting BK virus without symptoms of cystitis, although one of these patients did experience abnormalities of liver function that were otherwise unexplained. BK virus has already been implicated in hepatic dysfunction posttransplant, and in cystitis in nonimmunosuppressed children. We postulate that it may also be involved in the etiology of late hemorrhagic cystitis after BMT.