Duloxetine versus placebo in the treatment of patients with diabetic neuropathic pain in China / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Duloxetine, a selective serotonin and noradrenaline reuptake inhibitor, has been shown to be effective in treatment of diabetic peripheral neuropathic pain and approved for the management of patients with diabetic peripheral neuropathic pain (DPNP) in the United States, European Union, and many other countries. This study assessed the efficacy and safety of duloxetine in Chinese patients with diabetic peripheral neuropathic pain.</p><p><b>METHODS</b>This double-blind, randomized, placebo-controlled, flexible-dose study treated adult patients with diabetic peripheral neuropathic pain and baseline Brief Pain Inventory (BPI) 24-hour average pain severity ratings ≥ 4 with duloxetine 60 mg to 120 mg once daily or placebo for 12 weeks. Dose adjustments of duloxetine or matching placebo were based upon investigator's judgment of clinical response. Change from baseline to endpoint in BPI average pain was the primary efficacy outcome. Secondary outcome measures included BPI-severity and -Interference, Patient Global Impression of Improvement, Clinical Global Impressions of Severity, EuroQol: 5 Dimensions, Athens Insomnia Scale, and safety measures.</p><p><b>RESULTS</b>Of 215 patients randomized, 88.4% and 82.1% of patients in placebo and duloxetine groups, respectively, completed the study. Mean change from baseline to endpoint in BPI average pain was not statistically different between the treatment groups (P = 0.124). Duloxetine- treated patients showed significantly greater pain reduction compared with those in placebo group at weeks 1, 2, and 4 (P = 0.004, P = 0.009, and P = 0.006, respectively), but not at weeks 8 (P = 0.125) and 12 (P = 0.107). Duloxetine-treated patients experienced statistically significant improvement in Patient Global Impression of Improvement, Clinical Global Impression of Severity, area under the curve for pain relief, BPI-severity pain right now, and BPI-interference walking ability. Patients treated with duloxetine 120 mg once daily showed significantly greater pain reduction on the Brief Pain Inventory average pain score relative to placebo. Duloxetine-treated patients reported nausea, somnolence, anorexia, and dysuria significantly more than placebo.</p><p><b>CONCLUSIONS</b>Although the primary study endpoint was not achieved, the overall observed response pattern suggests the efficacy of duloxetine in the treatment of Chinese patients with diabetic peripheral neuropathic pain. The safety profile for duloxetine is similar to that reported in other global trials.</p>

Mechanism of improving effect of losartan on insulin sensitivity of non-insulin-dependent diabetes mellitus rats / 生理学报

The specific inhibition of angiotensin II action at AT(1) receptors by losartan has been shown to decrease peripheral insulin resistance in type 2 diabetic patients and animal models. We examined the effect of losartan on the expression of insulin receptor substrate 1 (IRS-1), protein kinase B (PKB) and glucose transporter 4 (GLUT4), as well as the phosphorylation status of IRS-1 and the association between IRS-1 and phosphatidylinositol (PI) 3-kinase in skeletal muscle from fat-fed and-streptozotocin (STZ)-treated rats, an animal model of type 2 diabetes mellitus. In addition, the effects of losartan on GLUT4 translocation in muscle cells and on insulin sensitivity were also evaluated. Muscle tissues were isolated from male losartan-treated and untreated normal or non-insulin-dependent diabetes mellitus (NIDDM) rats with a dose of 4 mg/kg per day for 6 weeks. Oral administration of losartan improved insulin sensitivity, which was determined by an oral glucose tolerance test (OGTT). In skeletal muscles, the protein levels of IRS-1, PKB and GLUT4 in NIDDM rats were not significantly different from those of the control rats, and they were not affected by losartan. The levels of IRS-1 tyrosine phosphorylation, PI 3-kinase activity associated with IRS-1 and PKB activation after stimulation with insulin in muscle tissue of NIDDM rats were significantly decreased (P<0.01) compared with those in the control rats, while they were not increased by losartan. Losartan had a major effect on GLUT4 translocation in myocytes, as it significantly increased (P<0.05) the insulin-induced amounts of GLUT4 in plasma membrane (PM) and T-tubules (TT) in myocytes from NIDDM rats. Consistent with these results, the plasma glucose level in losartan-treated NIDDM rats was decreased (P<0.05) compared with that in untreated NIDDM rats. Our results suggest that losartan may exert beneficial effects on insulin resistance by increasing the translocation of GLUT4 in muscle tissue, which is probably associated with a non-PI 3-kinase-dependent mechanism.