Genetic disposition and modifiable factors independently associated with anemia in patients with type 2 diabetes mellitus

Targeting PKC alleviates iron overload in diabetes and hemochromatosis

Diabetes is one of the most prevalent chronic diseases worldwide. Iron overload increases the incidence of diabetes and aggravates diabetic complications that cause mortality. Reciprocally, diabetes potentially promotes body iron loading, but the mechanism remains not well understood. In this study, we demonstrated systemic iron excess and the upregulation of iron exporter ferroportin (Fpn) in the enterocytes and macrophages of multiple diabetic mouse models. Increased Fpn expression and iron efflux was also seen in the enterocytes of type 2 diabetic human patients. We further showed that protein kinase C (PKC), which is activated in hyperglycemia, was responsible for the sustained membrane expression of Fpn in physiological and in diabetic settings. For the first time, we identified that PKCs were novel binding proteins and positive regulators of Fpn. Mechanistically, hyperactive PKC promoted exocytotic membrane insertion while inhibited the endocytic trafficking of Fpn in the resting state. PKC also protected Fpn from internalization and degradation by its ligand hepcidin dependent on decreased ubiquitination and increased phosphorylation of Fpn. Importantly, the loss-of-function and pharmacological inhibition of PKC alleviated systemic iron overload in diabetes and hemochromatosis. Our study thus highlights PKC as a novel target in the control of systemic iron homeostasis.

Clinical and genetic markers of erythropoietin deficiency anemia in chronic kidney disease (predialysis) patients

Aim: To determine the clinical and genetic markers associated with erythropoietin deficiency anemia in predialysis individuals. Materials & methods: Patients were categorized into cases and control group. Demographic characteristics and clinical parameters were obtained from medical record review and serum EPO and ferritin were obtained with ELISA. HIF-1α (rs2057482), IL-1β (rs1143627) and EPO (rs1617640) gene polymorphism were genotyped. Results: Female gender, glomerular filtration rate, treatment with hematinics, anticoagulant and diuretic were strong predictors of EPO-deficient anemia in predialysis chronic kidney disease patients. Genetic polymorphism in the HIF-1α recessive model was associated with non-EPO-deficiency, followed by EPO recessive allele associated with low-serum erythropoietin and IL-1β recessive model with low hemoglobin level. Conclusion: EPO-deficiency anemia can be diagnosed more conveniently in the presence of biomarkers.

Impaired Glucose Tolerance is Associated with Enhanced Platelet-Monocyte Aggregation in Short-Term High-Fat Diet-Fed Mice

High-fat diet (HFD) feeding is known to induce metabolic dysregulation, however, less is known on its impact in promoting the hypercoagulable state. This current study aimed to evaluate platelet-monocyte aggregate (PMA) formation following short-term HFD feeding. This is particularly important for understanding the link between inflammation and the hypercoagulable state during the early onset of metabolic dysregulation. To explore such a hypothesis, mice were fed a HFD for 8 weeks, with body weights as well as insulin and blood glucose levels monitored on a weekly basis during this period. Basal hematological measurements were determined and the levels of spontaneous peripheral blood PMAs were assessed using whole blood flow cytometry. The results showed that although there were no significant differences in body weights, mice on HFD displayed impaired glucose tolerance and markedly raised insulin levels. These metabolic abnormalities were accompanied by elevated baseline PMA levels as an indication of hypercoagulation. Importantly, it was evident that baseline levels of monocytes, measured using the CD14 monocyte marker, were significantly decreased in HFD-fed mice when compared to controls. In summary, the current evidence shows that in addition to causing glucose intolerance, such as that identified in a prediabetic state, HFD-feeding can promote undesirable hypercoagulation, the major consequence implicated in the development of cardiovascular complications.

Distribution of CYP2C8 and CYP2C9 amino acid substitution alleles in South Indian diabetes patients: A genotypic and computational protein phenotype study

The CYP2C8 and CYP2C9 are two major isoforms of the cytochrome P450 enzyme family, which is involved in drug response, detoxification, and disease development. This study describes the differential distribution of amino acid substitution variants of CYP2C8 (*2-I269F & *3-R139K) and CYP2C9 (*2-C144R & *3-L359A) genes in 234 type 2 diabetes mellitus (T2DM) patients and 218 healthy controls from Andhra Pradesh, South India. Single locus genotype analysis has revealed that homozygous recessive genotypes of 2C8*2-TT (P ≤ .03), 2C9*2-TT (P ≤ .02), and heterozygous 2C9*3-AC (P ≤ .006) are seen to be increasingly present in the case group, indicating a significant level of their association with diabetes in Andhra population. The statistical significance of these recessive genotypes has persisted even under their corresponding allelic forms (P ≤ .01). Genotype association results were further examined by computational protein structure and stability analysis to assess the deleteriousness of the amino acid changes. The mutant CYP 2C8 and 2C9 (both *2 and *3) proteins showed structural drifts at both amino acid residue (range 0.43Å-0.77Å), and polypeptide chain levels (range 0.68Å-1.81Å) compared to their wild-type counterparts. Furthermore, the free energy value differences (range -0.915 to -1.38 Kcal/mol) between mutant and native protein structures suggests the deleterious and destabilizing potential of amino acid substitution polymorphisms of CYP genes. The present study confirms the variable distribution of CYP2C8 (*2 and *3) and CYP2C9 (*2 and *3) allelic polymorphisms among South Indian diabetic populations and further warrants the serious attention of CYP gene family, as a putative locus for disease risk assessment and therapy.

Anemia complicating type 2 diabetes: Prevalence, risk factors and prognosis

AIMS

To determine the prevalence, risk factors and prognosis of anemia in representative community-based patients with type 2 diabetes.

METHODS

Data from the Fremantle Diabetes Study Phase II (FDS2; n=1551, mean age 65.7years, 51.9% males) and Busselton Diabetes Study (BDS; n=186, mean age 70.2years, 50.0% males) cohorts, and from 186 matched BDS participants without diabetes, were analyzed. The prevalence of anemia (hemoglobin ≤130g/L males, ≤120g/L females) was determined in each sample. In FDS2, associates of anemia were assessed using multiple logistic regression and Cox proportional hazards modeling identified predictors of death during 4.3±1.2years post-recruitment.

RESULTS

The prevalence of anemia at baseline was 11.5% in FDS2 participants, 17.8% in BDS type 2 patients and 5.4% in BDS participants without diabetes. In FDS2, 163 of 178 patients with anemia (91.6%) had at least one other risk factor (serum vitamin B₁₂<140pmol/L, serum ferritin <30μg/L and/or transferrin saturation<20%, serum testosterone <10nmol/L (males), glitazone therapy, estimated glomerular filtration rate (eGFR) <60mL/min 1.73m², malignancy, hemoglobinopathy). More anemic than non-anemic FDS2 patients died (28.7% versus 8.0%; P<0.001). After adjustment for other independent predictors (age as time-scale, male sex, Aboriginality, marital status, smoking, eGFR), anemia was associated with a 57% increase in mortality (P=0.015).

CONCLUSIONS

Type 2 diabetes at least doubles the risk of anemia but other mostly modifiable risk factors are usually present. Anemia is associated with an increased risk of death after adjustment for other predictors.

Voltage-programming-based capillary gel electrophoresis for the fast detection of angiotensin-converting enzyme insertion/deletion polymorphism with high sensitivity

A voltage-programming-based capillary gel electrophoresis method with a laser-induced fluorescence detector was developed for the fast and highly sensitive detection of DNA molecules related to angiotensin-converting enzyme insertion/deletion polymorphism, which has been reported to influence predisposition to various diseases such as cardiovascular disease, high blood pressure, myocardial infarction, and Alzheimer's disease. Various voltage programs were investigated for fast detection of specific DNA molecules of angiotensin-converting enzyme insertion/deletion polymorphism as a function of migration time and separation efficiency to establish the effect of voltage strength to resolution. Finally, the amplified products of the angiotensin-converting enzyme insertion/deletion polymorphism (190 and 490 bp DNA) were analyzed in 3.2 min without losing resolution under optimum voltage programming conditions, which were at least 75 times faster than conventional slab gel electrophoresis. In addition, the capillary gel electrophoresis method also successfully applied to the analysis of real human blood samples, although no polymorphism genes were detected by slab gel electrophoresis. Consequently, the developed voltage-programming capillary gel electrophoresis method with laser-induced fluorescence detection is an effective, rapid analysis technique for highly sensitive detection of disease-related specific DNA molecules.