Adipokines as predictors of recovery from upper extremity soft tissue disorders

OBJECTIVES

To study the associations of adipokines with recovery from upper extremity soft tissue disorders (UESTDs) and to explore whether overweight or obesity modify these associations.

METHODS

In this follow-up study, patients seeking medical advice due to incipient upper extremity symptoms with symptom duration <1 month were included (n = 163). The outcome of the study was full or substantial recovery from UESTDs, assessed at 2, 8 and 12 weeks of follow-up. We studied the associations of four adipokines (leptin, adiponectin, resistin and visfatin) with recovery using the generalized estimating equation.

RESULTS

Of the study population, 27.5% reported full or substantial recovery at the 8-week follow-up and 32% at 12 weeks. Higher levels of resistin [odds ratio (OR) = 1.58, 95% CI 1.18, 2.11 for 1 s.d. increase] and visfatin (OR = 1.29, 95% CI 0.94, 1.78 for 1 s.d. increase) at baseline predicted a higher recovery rate at the 8-week follow-up. Moreover, higher levels of leptin predicted a lower rate of recovery (OR = 0.73, 95% CI 0.51, 1.02 for 1 s.d. increase). Adipokines did not predict recovery at 12 weeks. In subgroup analyses, high levels of resistin and visfatin at baseline predicted a higher recovery rate during follow-up in non-overweight patients.

CONCLUSION

The adipokines resistin and visfatin predicted recovery from UESTDs and the associations may be related to stimulation of anti-inflammatory response mechanisms. A higher level of leptin may prevent recovery from UESTDs.

Thrombin induced connective tissue growth factor expression in rat vascular smooth muscle cells via the PAR-1/JNK/AP-1 pathway

AIM

To investigate the signaling pathways involved in thrombin-induced connective tissue growth factor (CTGF) expression in rat vascular smooth muscle cells (VSMCs).

METHODS

Experiments were preformed on primary rat aortic smooth muscle cells (RASMCs) and a rat VSMC line (A10). CTGF protein levels were measured using Western blotting. Luciferase reporter genes and dominant negative mutants (DNs) were used to investigate the signaling pathways mediating the induction of CTGF expression by thrombin.

RESULTS

Thrombin (0.3-3.0 U/mL) caused a concentration- and time-dependent increase in CTGF expression in both RASMCs and A10 cells. Pretreating A10 cells with the protease-activated receptor 1 (PAR-1) antagonist SCH79797 (0.1 μmol/L) significantly blocked thrombin-induced CTGF expression, while the PAR-4 antagonist tcY-NH(2) (30 μmol/L) had no effect. The PAR-1 agonist SFLLRN-NH(2) (300 μmol/L) induced CTGF expression, while the PAR-4 agonist GYPGQV-NH(2) (300 μmol/L) had no effect. Thrombin (1 U/mL) caused time-dependent phosphorylation of c-Jun N-terminal kinase (JNK). Pretreating with the JNK inhibitor SP600125 (3-30 μmol/L) or transfection with DNs of JNK1/2 significantly attenuated thrombin-induced CTGF expression. Thrombin (0.3-3.0 U/mL) increased activator protein-1 (AP-1)-luciferase activity, which was inhibited by the JNK inhibitor SP600125. The AP-1 inhibitor curcumin (1-10 μmol/L) concentration-dependently attenuated thrombin-induced CTGF expression.

CONCLUSION

Thrombin acts on PAR-1 to activate the JNK signaling pathway, which in turn initiates AP-1 activation and ultimately induces CTGF expression in VSMCs.