Contribution of the familial and genetic factors on monocyte chemoattractant protein-1 variation in healthy human pedigrees

Association of CCL2 Gene Variants with Osteoarthritis

BACKGROUND AND AIMS

The chemokine (C-C motif) Ligand 2 (CCL2)/CCR2 signaling was associated with macrophage accumulation, synovitis and cartilage damage in a mouse osteoarthritis (OA) model.

MATERIALS AND METHODS

Here a case-control study in a Chinese Han population was conducted to investigate the possible association between the CCL2 gene polymorphism and risk of OA. DNA was extracted from 367 primary knee OA patients and 303 healthy controls. Then CCL2 gene polymorphisms were determined using a standard polymerase chain reaction restriction fragment length polymorphism. Plasma CCL2 levels were measured by using sandwich enzyme-linked immunosorbent assay (ELISA).

RESULTS

It was found the CCL2 gene rs1024611 and rs4586 polymorphisms significantly increased the risk of OA. Stratified analyses showed the risk of OA might be increased by rs1024611 polymorphism in males and non-drinkers, and was increased by rs4586 polymorphism among smokers and drinkers. The CC genotype of rs4586 polymorphism was significantly correlated with the increased CCL2 level compared to TT genotype.

CONCLUSIONS

In conclusion, CCL2 gene polymorphisms (rs1024611 and rs4586) confer susceptibility to OA and may be potential markers for early diagnosis of OA.

Reconstitution of the complete rupture in musculotendinous junction using skeletal muscle-derived multipotent stem cell sheet-pellets as a "bio-bond"

Background. Significant and/or complete rupture in the musculotendinous junction (MTJ) is a challenging lesion to treat because of the lack of reliable suture methods. Skeletal muscle-derived multipotent stem cell (Sk-MSC) sheet-pellets, which are able to reconstitute peripheral nerve and muscular/vascular tissues with robust connective tissue networks, have been applied as a “bio-bond”.

Methods. Sk-MSC sheet-pellets, derived from GFP transgenic-mice after 7 days of expansion culture, were detached with EDTA to maintain cell–cell connections. A completely ruptured MTJ model was prepared in the right tibialis anterior (TA) of the recipient mice, and was covered with sheet-pellets. The left side was preserved as a contralateral control. The control group received the same amount of the cell-free medium. The sheet-pellet transplantation (SP) group was further divided into two groups; as the short term (4–8 weeks) and long term (14–18 weeks) recovery group. At each time point after transplantation, tetanic tension output was measured through the electrical stimulation of the sciatic nerve. The behavior of engrafted GFP⁺ tissues and cells was analyzed by fluorescence immunohistochemistry.

Results. The SP short term recovery group showed average 64% recovery of muscle mass, and 36% recovery of tetanic tension output relative to the contralateral side. Then, the SP long term recovery group showed increased recovery of average muscle mass (77%) and tetanic tension output (49%). However, the control group showed no recovery of continuity between muscle and tendon, and demonstrated increased muscle atrophy, with coalescence to the tibia during 4–8 weeks after operation. Histological evidence also supported the above functional recovery of SP group. Engrafted Sk-MSCs primarily formed the connective tissues and muscle fibers, including nerve-vascular networks, and bridged the ruptured tendon–muscle fiber units, with differentiation into skeletal muscle cells, Schwann cells, vascular smooth muscle, and endothelial cells.

Discussion. This bridging capacity between tendon and muscle fibers of the Sk-MSC sheet-pellet, as a “bio-bond,” represents a possible treatment for various MTJ ruptures following surgery.

Prediction of subclinical atherosclerosis by serum osteoprotegerin in premenopausal women with systemic lupus erythematous: correlation of osteoprotegerin with monocyte chemotactic protein-1

Objective

Patients with systemic lupus erythematosus (SLE) have increased risk for cardiovascular disease. Previous studies disclosed the association of serum osteoprotegerin (OPG) with the presence of symptomatic atherosclerosis in the general population and several disease conditions. We thus investigated the association between serum OPG levels and subclinical atherosclerosis in premenopausal SLE patients.

Methods

Serum OPG levels and carotid artery intima-media thickness (IMT) were measured in 181 premenopausal SLE patients and age-matched 85 control subjects. Traditional cardiovascular risk factors and SLE-related factors were analyzed.

Results

Patients with SLE had significantly increased serum OPG levels (1086 versus 517 pg/ml, p < 0.001) and carotid IMT (0.63 versus 0.45 mm, p < 0.001) compared with control subjects. Carotid IMT significantly increased across the quartiles of OPG. Logistic regression analysis revealed that compared to the lowest OPG quartile, the odds ratio (OR, 95% confidence interval) for increased carotid IMT in quartile 2, 3, and 4 was 1.126 (1.013–1.801), 1.562 (1.268–2.799), and 4.460 (1.126–7.128), respectively, after multiple adjustments ( p for trend across quartiles < 0.001). These associations remained significant after further adjustment for inflammatory parameters. Interestingly, serum monocyte chemotactic protein-1 (MCP-1) levels were positively correlated with serum OPG levels (γ = 0.332, p < 0.001). Parallel analysis showed that serum MCP-1 was also an independent predictor of carotid IMT incrassation, but this association was lost when serum OPG was included in the model.

Conclusion

Serum OPG levels were increased and correlated with serum MCP-1 levels in premenopausal SLE patients. Increased serum OPG was independently associated with subclinical atherosclerosis in these patients.

Osteoprotegerin contributes to the metastatic potential of cells with a dysfunctional TSC2 tumor-suppressor gene

In addition to its effects on bone metabolism, osteoprotegerin (OPG), a soluble member of the tumor necrosis factor family of receptors, promotes smooth muscle cell proliferation and migration and may act as a survival factor for tumor cells. We hypothesized that these cellular mechanisms of OPG may be involved in the growth and proliferation of lymphangioleiomyomatosis (LAM) cells, abnormal smooth muscle-like cells with mutations in one of the tuberous sclerosis complex tumor-suppressor genes (TSC1/TSC2) that cause LAM, a multisystem disease characterized by cystic lung destruction, lymphatic infiltration, and abdominal tumors. Herein, we show that OPG stimulated proliferation of cells cultured from explanted LAM lungs, and selectively induced migration of LAM cells identified by the loss of heterozygosity for TSC2. Consistent with these observations, cells with TSC2 loss of heterozygosity expressed the OPG receptors, receptor activator of NF-κB ligand, syndecan-1, and syndecan-2. LAM lung nodules showed reactivities to antibodies to tumor necrosis factor-related apoptosis-inducing ligand, receptor activator of NF-κB ligand, syndecan-1, and syndecan-2. LAM lung nodules also produced OPG, as shown by expression of OPG mRNA and colocalization of reactivities to anti-OPG and anti-gp100 (HMB45) antibodies in LAM lung nodules. Serum OPG was significantly higher in LAM patients than in normal volunteers. Based on these data, it appears that OPG may have tumor-promoting roles in the pathogenesis of lymphangioleiomyomatosis, perhaps acting as both autocrine and paracrine factors.

Association between CCL2 haplotypes and knee osteoarthritis

We examined five single nucleotide polymorphisms (SNPs) and reconstructed 5-locus haplotypes of the CCL2 gene, in knee osteoarthritis (OA) cases and in controls. The CCL2 rs2857657 variant (G) allele was observed more frequently in female knee OA cases than in controls. One haplotype (H5) was observed exclusively in the control group (f = 2.3%). Genetic variation in the CCL2 gene may be associated with knee OA.

Quantitative genetic study of amphiregulin and fractalkine circulating levels--potential markers of arthropathies

OBJECTIVE

Amphiregulin (AREG) and Fractalkine (FRACT), are involved in a variety of normal and pathological processes, and are both suggested to be relevant to joint degeneration. The aims of the present study included (1) testing association between circulating levels of these biomarkers and joint pathologies, (2) evaluation of the putative genetic and familial factors' effect on AREG and FRACT variability.

DESIGN

The study was conducted in the family-based sample of 923 Caucasian individuals. Variance component analysis was used to assess contribution of genetic and environmental factors to variability of AREG and FRACT concentration.

RESULTS

The mean levels of FRACT were significantly higher in the affected group with arthropathies (synovial joints osteoarthritis (OA) and disc degenerative disease, DDD) then in the control group (P<0.0004). Circulating AREG levels were higher in DDD (P=0.0272). Genetic factors constituted the main source of the interindividual differences of the AREG and FRACT levels in our sample, and explained 29.68% and 41.68% of the total variation, respectively. The phenotypic correlation between AREG and FRACT was substantial (r=0.55, P=0.0001) and was associated with both common genetic and environmental factors. Specifically, 30% of the phenotypic correlation between AREG and FRACT was due to common genetic effects.

CONCLUSIONS

Further studies are required to assess relevancy of FRACT to clinical diagnosis and prognosis of arthropathies, to investigate the mechanisms behind the observed phenotypic and genetic covariation among the studied biomarkers, and to explore specific genetic polymorphisms affecting AREG and FRACT variation.

Association between radiographic hand osteoarthritis and RANKL, OPG and inflammatory markers

OBJECTIVE

The aim of the study was to evaluate the association between prevalence and severity of radiographic hand osteoarthritis (OA) and serum levels of systemic inflammatory markers in a community-based population sample.

DESIGN

A cross-sectional observational study was conducted on a population comprised 1452 Chuvashians (763 males, aged 49.23 ± 17.43; and 689 females, aged 50.37 ± 17.47 years). OA was evaluated in 14 joints of each hand using Kellgren and Lawrence (K-L), joint space narrowing (JSN) and osteophyte (OS) scores. Serum levels of systemic inflammatory and osteoclastogenic cytokines were measured by an enzyme-linked immunosorbent assay (ELISA). Statistical analyses included descriptive statistics, correlation analysis and multiple linear regressions.

RESULTS

Monocyte chemotactic protein-1 (MCP-1) and osteoprotegerin (OPG) levels were associated with OA traits, but the statistically significant correlations were weak and/or moderate. In particular, the MCP-1 inflammation marker showed a statistically significant association with JSN (β=0.077, P=0.022) and OS (β=0.067, P=0.024) scores, but not with the number of affected joints (K-L ≥ 2). OPG was significantly correlated with the scores as to the number of affected joints (β=0.063, P=0.035) and OS (β=0.077, P=0.028). No significant associations were found between levels of other inflammatory [interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-17] and osteoclastogenic [receptor activator for nuclear factor κ B ligand (RANKL), macrophage colony-stimulating factor (M-CSF)] cytokines and OA characteristics.

CONCLUSIONS

This study strengthens the premise that OPG might be a valid biomarker of hand OA. Confirmation of these results in larger cohorts of patients will reinforce our theory that the RANKL/OPG pathway is a suitable target for developing novel agents against OA.

Circulating osteoprotegerin levels are elevated and correlated with antiphospholipid antibodies in patients with systemic lupus erythematosus

Patients with antiphospholipid syndrome (APS) have an increased risk for the development of thrombotic complications. Recent studies indicate that osteoprotegerin (OPG) acts as an important molecule in the development of vascular diseases. The aim of the present study was to examine the association between serum OPG levels and APS manifestations in patients with SLE. Seventy-nine patients with SLE and ninety-two healthy controls, matched for age and sex, were included in this study. Serum levels of OPG, monocyte chemoattractant protein(MCP)-1 and soluble E-selectin were determined by ELISA. At the time of serum sampling, various clinical and laboratory parameters were assessed. We found that serum levels of OPG were significantly higher in patients with SLE than in healthy controls (1236 ± 82 vs 967 ± 37 pg/mL, P = 0.003). Particularly, serum OPG levels were significantly higher in SLE patients with APS than those without (1615 ± 191 vs 1171 ± 91 pg/mL, P = 0.006). Serum OPG levels correlated with titres of IgG anti-cardiolipin antibody ( P = 0.026) and anti-β2-glycoprotein I antibody ( P < 0.001). Moreover, serum OPG also correlated with serum levels of sE-selectin ( P = 0.002), which is an endothelial cell activation marker, and MCP-1 ( P = 0.003), a well known chemokine implicated in thrombogenesis. Collectively, serum OPG levels were increased in SLE patients with APS and correlated with titres of antiphospholipid antibodies, suggesting that OPG might be linked to the development of APS.

Pathophysiology and clinical manifestations of osteoporosis

Osteoporosis is a complex skeletal disorder in which compromised bone strength increases the risk of fragility fractures. Recent scientific advances in bone biology and immunology have greatly expanded our insights into the pathogenesis of osteoporosis. For those with osteoporotic fractures, however, the physical and psychological effects remain severe. Primary care physicians need to understand the basic mechanisms of bone physiology and pathophysiology in order to both prevent and treat this devastating disorder.