TGFß2 Upregulates Tyrosinase Activity through Opsin-3 in Human Skin Melanocytes In Vitro.

Opsin-3 (OPN3) is a potential key regulator of human melanocyte melanogenesis. How OPN3-mediated regulation of melanocyte melanogenesis is triggered is largely unclear. TGFß can inhibit the growth of human melanocytes and reduce melanin synthesis in melanocytes. However, whether TGFß2 can modulate pigmentation in normal human primary melanocytes through OPN3 is entirely unknown. In this study, we constructed a coculture model with human epidermal melanocytes and keratinocytes. OPN3, tyrosinase (TYR), tyrosinase-related protein (TRP)-1, and TRP-2 expression and TYR activity were detected to be higher in cocultured cells than in monocultured cells. Moreover, elevated levels of TGFß2 were detected in the culture supernatant of melanocytes cocultured with keratinocytes. OPN3 inhibition in melanocytes decreased TYR, TRP-1, and TRP-2 expression and downregulated TYR activity. Our findings indicate that TGFß2 upregulates TYR activity and TRP-1 and TRP-2 expression in human melanocytes through OPN3 and downstream calcium-dependent G-protein coupled signaling pathways to induce melanogenesis. Interestingly, treatment with the TGFß2 receptor inhibitor LY2109761 (10 µM) did not inhibit TGFß2-induced melanocyte melanogenesis though OPN3. Collectively, our data suggest that TGFß2 upregulates TYR activity through OPN3 through a TGFß2 receptor-independent and calcium-dependent G-protein coupled signaling pathway.

Incidence of pocket hematoma after electrophysiological device placement: dual antiplatelet therapy versus low-molecular-weight heparin regimen.

BACKGROUND: Given the increasing number of patients who require dual antiplatelet (DAP) therapy and electrophysiological device (EPD) placement, perioperative antiplatelet management is a current challenge. In this study, we investigated the incidence of pocket hematoma formation after EPD placement in patients undergoing DAP therapy or an alternative low-molecular-weight heparin (LMWH) regimen. METHODS: This clinical observational study was performed from July 2010 to July 2012. In total, 171 patients were enrolled in the analysis after meeting the inclusion criteria. These patients were divided into two groups: 86 patients were treated with DAP therapy at the time of device implantation, and the DAP therapy was discontinued for 5 to 7 days and replaced with enoxaparin before device implantation in the other 85 patients. Adenosine phosphate (ADP)-mediated platelet aggregation and arachidonic acid-induced platelet aggregation were tested preoperatively. We compared the incidence of pocket hematoma between the two groups and the association of pocket hematoma development with ADP-mediated platelet aggregation and arachidonic acid-induced platelet aggregation. RESULTS: The incidence of pocket hematoma in the patients who continued DAP was lower than that in the patients who replaced the dual antiplatelet regimen with LMWH (3.49% vs. 16.47%, respectively; X (2) = 6.66, P < 0.01). Among the patients who continued DAP therapies, the rate of ADP-mediated platelet aggregation inhibition in patients with pocket hematomas was higher than that in patients without pocket hematomas. None of the patients undergoing DAP or enoxaparin therapy developed pocket infection, thromboembolic events, or other serious complications. Multiple logistic regression analysis revealed that LMWH therapy was an independent risk factor for the development of pocket hematoma (RR = 0.054, 95%CI = 0.012-0.251). Furthermore, patients undergoing LMWH therapy were 5.1-fold more likely to develop pocket hematomas than were DAP-treated individuals. CONCLUSION: Continuance of DAP therapy does not increase the risk of pocket hematoma formation after EPD placement.

Stress-induced hyperglycemia after hip fracture and the increased risk of acute myocardial infarction in nondiabetic patients.

OBJECTIVE: To investigate the risk of acute myocardial infarction (AMI) following stress hyperglycemia after hip fracture. RESEARCH DESIGN AND METHODS: From February 2007 to February 2012, we carried out a prospective observational analysis of 1,257 consecutive patients with no history of diabetes who suffered hip fractures. Fasting blood glucose (FBG) and glycosylated hemoglobin tests as well as electrocardiography, ultrasonic cardiography, and chest X-ray examinations were performed after admission. All selected hip fracture patients were divided into stress hyperglycemia and non-hyperglycemia groups according to their FBG, and the incidence of AMI was monitored. RESULTS: Among the patients enrolled, the frequency of stress hyperglycemia was 47.89% (602/1,257) and that of AMI was 9.31% (117/1,257), and the occurrence of AMI in the stress hyperglycemia group was higher than in the non-hyperglycemia group (12.46 vs. 6.41%, P<0.05). In the stress hyperglycemia patients, FBG reached maximum levels at 2-3 days after hip fractures and then decreased gradually. The AMI incidence (62.67% [47/75]) of the stress hyperglycemia group was highest in the initial 3 days after hip fracture, significantly coinciding with the FBG peak time (P<0.05). In all patients with AMI, non-ST-segment elevation myocardial infarction occurred more often than ST-segment elevation myocardial infarction (62.39% [73/117] vs. 37.61% [44/117]). CONCLUSIONS: Stress-induced hyperglycemia after hip fracture increased the risk of AMI.