Lipoprotein (a) and atherogenic indices in Sudanese patients with type 2 diabetes

Comparison of Multiple Equations for Low-Density Lipoprotein Cholesterol Calculation Against the Direct Homogeneous Method

Objective

Several equations have been proposed as alternatives for the reference method of measuring low-density lipoprotein cholesterol (LDL-C). This study aimed to evaluate these alternatives in comparison to the homogeneous method and validate their clinical utility.

Methods

Data on the lipid profiles of 1,006 Sudanese individuals were analyzed. The paired t-test was used to compare the results of direct and calculated LDL-C. Bland-Altman plots were used to demonstrate the differences between the measured and calculated LDL-C against the mean values. Linear regression was conducted, using the correlation coefficient (r) to quantify the relationship between methods. The bias between measured and calculated LDL-C was compared to the National Cholesterol Education Program Laboratory Standardization Panel criteria (i.e., accuracy within ±4% of expected values).

Results

The Martin and Anandaraja equations showed no significant difference compared to directly measured LDL-C (p>0.05). The DeLong equation indicated an insignificant difference only with a 99% confidence interval (p>0.01). The Martin, DeLong, and Teerakanchana equations exhibited the smallest limits of agreement, with data points concentrated closely around the mean difference line. Linear regression analysis revealed strong positive correlations (r>0.8) for most equations, except for the Ahmadi equation. The DeLong, Rao, and Martin equations demonstrated superior performance for LDL cutoff points (bias within ± 4%). The DeLong formula also showed superior performance at different lipid levels, closely followed by the Martin equation (bias within ±4%).

Conclusion

The DeLong and Martin equations outperformed others, such as the widely used Friedewald equation, in calculating LDL-C. Further validation studies are needed.

Biochemical characterization of high fat diet fed and low dose streptozotocin induced diabetic Wistar rat model

The development of a stable disease model with an adequate biochemical profile is crucial for the preclinical investigation of new antidiabetic agents. This study aimed at optimization and characterization of high fat diet (HFD) fed streptozotocin (STZ) induced type 2 diabetes mellitus (type 2 DM) Wistar rat model. Wistar rats fed with HFD for four weeks received STZ (30, 40, and 50 mg/kg, intraperitoneal). Diabetic rats were observed for four more weeks and sacrificed. Non- injected healthy Wistar rats and HFD-fed rats were used as control groups. The glucose status and the lipid profile of the model were assessed. STZ-induced rats showed significant dose-dependent alterations in fasting serum insulin and glucose, homeostatic model assessment- insulin resistance (HOMA-IR), HOMA- β cell function (HOMA- β), quantitative insulin sensitivity check index (QUICKI), total cholesterol (TC), triglycerides (TG) and atherogenic index (AI). STZ 50 mg/kg group rats showed significant increase in glycated hemoglobin (HbA_1c), low density lipoprotein cholesterol (LDL-C) and very low density lipoprotein cholesterol (VLDL-C) levels compared to healthy rats. The atherogenic risk index (ARI), the Castelli risk index-I (CRII), and CRI-II were significantly (p < 0.05) high in the STZ 40 mg/kg and 50 mg/kg group rats. Results suggest that the Wistar rats fed with HFD rich in saturated fat for four weeks followed by a single intraperitoneal dose of 50 mg/kg of STZ would produce a stable diabetic model which closely mimic biochemical features of type 2 DM. Key messages: Wistar rats fed with HFD rich in saturated fat for four weeks followed by a single intraperitoneal dose of 50 mg/kg STZ would produce a stable diabetic model that closely mimics the biochemical characteristics of type 2 DM characterized by insulin resistance, relative insulin deficiency and impaired β cell function.

Serum Lipoprotein (a) Levels in Black South African Type 2 Diabetes Mellitus Patients

Lipoprotein (a) (Lp(a)) which is a low-density lipoprotein-like particle containing apo(a) is considered as an emergent cardiovascular risk factor. Type 2 diabetes mellitus (T2DM) is associated with a two- to threefold increase in the risk of cardiovascular disease (CVD). The aim of this study was to investigate the levels of Lp(a) in Black South African T2DM patients and its association with other metabolic factors. 67 T2DM patients and 48 healthy control participants were recruited for the cross-sectional study. The Lp(a) level was determined by ELISA and the result was analyzed using SPSS. The Lp(a) level in diabetics was found to be significantly increased (P = 0.001) when compared to the normal healthy group. In the diabetic group, the Lp(a) levels correlated significantly with the duration of diabetes (P = 0.008) and oxidized LDL (ox-LDL) levels (P = 0.03) and decreased total antioxidant capacity (P = 0.001). The third tertile of Lp(a) was significantly correlated with increased ox-LDL, C-reactive protein, and triglycerides and decreased total antioxidant capacity.