Comment

Diabetes fights for recognition

Juniperus procera, a coniferous tree in the cypress family, is one of the famous medicinal plants traditionally used in the southern area of the Arabian peninsula. This study examined the anti-hyperglycemic action of Juniperus procera extract (JPE) on diabetic rats. Sixty male rats were divided into 6 equal groups: control, control treated with JPE (200 mg/kg), diabetic, diabetic treated with insulin (1 U/kg), diabetic treated with JPE (200 mg/kg), and diabetic treated with both insulin and JPE. Blood and tissue samples were collected for serum chemistry, gene expression, and immunohistochemistry analyses, the results of which revealed hyperglycemia and inflammation following diabetes induction. Administration of JPE alone or with insulin reduced the hyperglycemia reported in diabetic rats by 25 %. The immunohistochemical examination of pancreatic tissues demonstrated a moderate restoration of insulin and NF-κB expression in pancreatic and hepatic tissues. Significant recovery was observed for glutathione-S-transferase (GST), superoxide dismutase (SOD), and glutathione peroxidase (GPx) mRNA expression in the livers of rats treated with JPE. Administration of JPE led to similar amelioration of the mRNA expression of pyruvate kinase (PK) and phosphoenol pyruvate carboxy kinase (PEPCK) in the livers of diabetic rats. In addition, diabetic rats treated with insulin, JPE, or a combination of these agents demonstrated an improvement in the mRNA expression of IRS-1 and IRS-2 in hepatic and pancreatic tissues, reaching levels approaching normal. Our findings led us to conclude that JPE has a powerful anti-inflammatory effect accompanied by a moderate hypoglycemic effect that occurs via different mechanisms.

The WHO and American Diabetes Association criteria for diagnosing diabetes mellitus assume the presence of a glycaemic threshold with high sensitivity for identifying retinopathy. However, this assumption is based on data from three previous studies that had important limitations in detecting retinopathy. We aimed to provide updated data for the relation between fasting plasma glucose (FPG) and retinopathy, and to assess the diagnostic accuracy of current FPG thresholds in identifying both prevalent and incident retinopathy.

We examined the data from three cross-sectional adult populations: those in the Blue Mountains Eye Study (BMES, Australia, n=3162), the Australian Diabetes, Obesity and Lifestyle Study (AusDiab, Australia, n=2182), and the Multi-Ethnic Study of Atherosclerosis (MESA, USA, n=6079). Retinopathy was diagnosed from multiple retinal photographs of each eye, and graded according to the modified Airlie House Classification system. Plasma glucose concentrations were measured from fasting venous blood samples.

The overall prevalence of retinopathy was 11·5% in BMES (95% CI 10·4–12·6%), 9·6% in AusDiab (8·4–10·9), and 15·8% in MESA (14·9–16·7). However, we found inconsistent evidence of a uniform glycaemic threshold for prevalent and incident retinopathy, with analyses suggesting a continuous relation. The widely used diabetes FPG cutoff of 7·0 mmol/L or higher had sensitivity less than 40% (range 14·8–39·1) for detecting retinopathy, with specificity between 80·8% and 95·8%. The area under receiver operating characteristic curves for FPG and retinopathy was low and ranged from 0·56 to 0·61.

We saw no evidence of a clear and consistent glycaemic threshold for the presence or incidence of retinopathy across different populations. The current FPG cutoff of 7·0 mmol/L used to diagnose diabetes did not accurately identify people with and without retinopathy. These findings suggest that the criteria for diagnosing diabetes could need reassessment.