Berhane Seyoum

Elevated circulating lipasin/betatrophin in human type 2 diabetes and obesity

Lipasin (also known as C19ORF80, RIFL, ANGPTL8 and betatrophin) is a newly discovered circulating factor that regulates lipid metabolism and promotes pancreatic β-cell proliferation. Whether circulating levels of lipasin in humans are altered in a) type 2 diabetes; b) obesity and c) the postprandial state, however, is unknown. The current study aimed to compare serum lipasin levels in those who were a) non-diabetic (N = 15) or diabetic (BMI- and age-matched; N = 14); b) lean or obese (N = 53 totally) and c) fasting and 2 hours following a defined meal (N = 12). Serum lipasin levels were determined by the enzyme-linked immunosorbent assay. Lipasin levels [mean ± SEM] were increased by more than two fold (P < 0.001) in the diabetic patients (5.56 ± 0.73 ng/mL) as compared to the control subjects (2.19 ± 0.24 ng/mL). Serum lipasin levels were positively correlated with BMI (rho = 0.49, P < 0.001), and showed a 35% increase 2 hours following a defined meal (P = 0.009). Therefore, lipasin/betatrophin is nutritionally-regulated hepatokine that is increased in human type 2 diabetes and obesity.

Prevalence of gestational diabetes mellitus in rural pregnant mothers in northern Ethiopia

In a community based survey of gestational diabetes in 18 rural villages of the eastern zone of Tigray administrative region, northern Ethiopia, a total of 890 pregnant women with gestational age of 24 weeks and above were examined for gestational diabetes mellitus based on WHO criteria. A 75 gm oral glucose tolerance test was performed on each subject with measurement of glucose at 0 and 2 h. Blood glucose was determined by glucose oxidase method using capillary blood (Accutrend alpha, Boehringer Mannheim). The mean age of the mothers was 27.4 +/- 7.1 years. Forty four percent of the subjects were multiparas. The prevalence rate of gestational diabetes mellitus was found to be 3.7% (95% CI 2.5-4.9). The mean blood glucose 2 h after glucose load in those pregnant diagnosed to have gestational diabetes mellitus was 154.6 +/- 14.4 mg/dl (J.W. Rich-Edwards, G.A. Colditz, M.J. Stampfer, W.C. Willett, M.W. Gillman, C. Hennekens, F.E. Speizer, J.E. Manson, Birth weight and the risk for type 2 diabetes mellitus in adult women, Annu. Intern. Med. 130 (1999) 278-284). The prevalence of gestational diabetes mellitus in this region of the country is high as compared to other parts of Africa. The possible role and contribution of exposure of the general population in this area to chronic malnutrition as a result of prolonged famine, drought and war, to the high prevalence of gestational diabetes mellitus warrants further study.

Systematic inspection of insulin injection sites for local complications related to incorrect injection technique.

We systematically inspected insulin injection sites in 100 insulin-requiring patients attending the Diabetic Clinic of the Tikur Anbassa Hospital (TAH) in order to identify local complications related to incorrect injection technique: local complications were found in 53 cases: skin hyperpigmentation and/or indurations in 30 patients; and fat atrophy or hypertrophy in 31 patients. Illiteracy was significantly more common among those with local complications (18/53 versus 6/47, χ2 5.03, P < 0.05). Mean fasting blood glucose on the day of the inspection was significantly higher (14.9 +6.3 mmol/l versus 10.5 + 6.1 mmol/l, P < 0.001) and a fasting blood glucose > 10 mmol/l more common (41/53 versus 20/47, χ2 14.1, P < 0.0005) in those with than in those without local complications. There was no significant difference between the two groups in mean duration of diabetes (6.9 + 5.6 years versus 6.6 + 5.8 years), frequency of hypoglycaemic episodes (12/53 versus 5/47, χ2 1.76, P > 0.05) or mean daily insulin dose (44 + 18 units versus 44 + 22 units per day). Therefore, we concluded that local complications resulting from incorrect injection technique, a common finding in the group of patients studied, may be common among insulin requiring diabetic patients in general. Incorrect insulin injection causes local complications and disfigurement which may compromise compliance. Furthermore, insulin absorption tends to be erratic from intradermal and fat hypertrophy sites thus interfering with effective diabetic control. Insulin injection sites should be inspected routinely to detect and correct faulty technique promptly.

Exercise capacity is a predictor of cardiovascular events in patients with type 2 diabetes mellitus.

Peak exercise oxygen consumption (peak VO2), as measured by expired gas analysis, is an accurate, reproducible and reliable method for determining exercise capacity. In this study, a cohort of 468 patients with type 2 diabetes underwent graded exercise testing to measure peak VO2 at baseline; the cohort was followed for five years for the occurrence of cardiovascular disease (CVD) events. Patients who developed CVD events during the five-year follow-up period were found to have significantly lower baseline peak VO2, as compared to those who did not (p=0.02). Analysis by gender showed that the mean peak VO2 in male patients who developed CVD events was significantly lower than the peak VO2 in those who did not (p<0.03). Multiple Cox regression analysis also showed low peak VO2 to be an independent factor. In conclusion, patients with type 2 diabetes mellitus with reduced peak VO2 during exercise have a greater tendency to develop future CVD events.

Increased Interaction with Insulin Receptor Substrate-1, a Novel Abnormality in Insulin Resistance and Type 2 Diabetes

Insulin receptor substrate 1 (IRS1) is a key mediator of insulin signal transduction. Perturbations involving IRS1 complexes may lead to the development of insulin resistance and type 2 diabetes (T2D). Surprisingly little is known about the proteins that interact with IRS1 in humans under health and disease conditions. We used a proteomic approach to assess IRS1 interaction partners in skeletal muscle from lean healthy control subjects (LCs), obese insulin-resistant nondiabetic control subjects (OCs), and participants with T2D before and after insulin infusion. We identified 113 novel endogenous IRS1 interaction partners, which represents the largest IRS1 interactome in humans and provides new targets for studies of IRS1 complexes in various diseases. Furthermore, we generated the first global picture of IRS1 interaction partners in LCs, and how they differ in OCs and T2D patients. Interestingly, dozens of proteins in OCs and/or T2D patients exhibited increased associations with IRS1 compared with LCs under the basal and/or insulin-stimulated conditions, revealing multiple new dysfunctional IRS1 pathways in OCs and T2D patients. This novel abnormality, increased interaction of multiple proteins with IRS1 in obesity and T2D in humans, provides new insights into the molecular mechanism of insulin resistance and identifies new targets for T2D drug development.

Effects of 3T3 adipocytes on interleukin-6 expression and insulin signaling in L6 skeletal muscle cells.

OBJECTIVE Central adiposity and inflammation play key roles in the development of insulin resistance through the effects of pro-inflammatory adipokines such as IL-6, but the effect of infiltrating adipocytes in skeletal muscle tissues is not known. Communications between muscle cells and fat cells may contribute to the inflammatory response associated with insulin resistance. METHODS In this study we used a co-culture system of skeletal muscle (L6) and adipocyte (3T3-L1) cell lines to study expression of the inflammatory cytokine IL-6 and changes in insulin signaling. This model could mimic the adipocytes infiltrating myocytes that is commonly seen in obese patients. RESULTS When plated alone the L6 cells express IL-6 mRNA and secrete IL-6 protein, both of which are increased when the cells are challenged with the bacterial lipopolysaccharide (LPS). In contrast, the 3T3-L1 cells had very little expression of IL-6 mRNA or protein. Co-culture of 3T3-L1 pre-adipocytes with L6 cells, at a density ratio of 1:10, respectively, increased IL-6 expression significantly and decreased insulin-stimulated Akt phosphorylation. To examine the role of IL-6 in insulin sensitivity we incubated the L6 cells with IL-6. A brief challenge of L6 cells with IL-6 enhanced insulin-stimulated Akt phosphorylation. In contrast, incubation of the L6 cells with IL-6 for 96h markedly decreased insulin-stimulated Akt phosphorylation. CONCLUSION The enhanced IL-6 mRNA expression and IL-6 release in L6 myocytes co-cultured with 3T3-L1 cells indicate an important interaction between adipocytes and myocytes. This observation may shed some light on the long-standing enigma of obesity-induced insulin resistance where infiltration of the skeletal muscle by preadipocytes/adipocytes is evident.

Plasma Lactate Levels Increase during Hyperinsulinemic Euglycemic Clamp and Oral Glucose Tolerance Test.

Insulin resistance, which plays a central role in the pathogenesis of type 2 diabetes (T2D), is an early indicator that heralds the occurrence of T2D. It is imperative to understand the metabolic changes that occur at the cellular level in the early stages of insulin resistance. The objective of this study was to determine the pattern of circulating lactate levels during oral glucose tolerance test (OGTT) and hyperinsulinemic euglycemic clamp (HIEC) study in normal nondiabetic subjects. Lactate and glycerol were determined every 30 minutes during OGTT and HIEC on 22 participants. Lactate progressively increased throughout the HIEC study period (P < 0.001). Participants with BMI < 30 had significantly higher mean M-values compared to those with BMI ≥ 30 at baseline (P < 0.05). This trend also continued throughout the OGTT. In addition, those with impaired glucose tolerance test (IGT) had significantly higher mean lactate levels compared to those with normal glucose tolerance (P < 0.001). In conclusion, we found that lactate increased during HIEC study, which is a state of hyperinsulinemia similar to the metabolic milieu seen during the early stages in the development of T2D.

Idiopathic Hypoparathyroidism Presenting With Severe Hypocalcemia and Asymptomatic Basal Ganglia Calcification Followed by Acute Intracerebral Bleed

OBJECTIVE To report a case of idiopathic hypoparathyroidism presenting with severe hypocalcemia and intracerebral calcifications that resulted in a spontaneous intracerebral bleed. METHODS We present the clinical, laboratory, and radiologic findings in a woman with idiopathic hypoparathyroidism who developed spontaneous intracerebral bleed in the setting of chronic intracerebral calcifications. RESULTS A 37-year-old woman presented with vague symptoms of hypocalcemia. Clinical evaluation revealed brisk deep tendon reflexes and positive Chvosteks and Trousseaus signs. The serum calcium level was 3.7 mg/dL (reference range, 8.0 to 10.6 mg/dL) and the phosphorus level was 8.2 mg/dL (reference range, 2.3 to 5.0 mg/dL). Serum intact parathyroid hormone was undetectable. Computed tomography of the head showed extensive bilateral symmetrical calcification of basal ganglia and dentate nucleus in the cerebellum and centrum semiovale. Fluid and electrolytes were replaced appropriately, and calcium and calcitriol were prescribed. While in the hospital, the patient developed an acute intracerebral bleed confirmed by computed tomography. The patient recovered without neurologic sequelae and was discharged from the hospital on calcium supplementation and calcitriol. Repeated computed tomography of the head 3 years later demonstrated complete resolution of the bleed. CONCLUSION This case suggests that patients with severe hypoparathyroidism and intracerebral calcification may be at risk for spontaneous intracerebral bleed and should be monitored accordingly.

Pleural empyema due to Salmonella paratyphi in a patient with AIDS

Pleural empyema due to Salmonella has rarely been reported in immunocompromised patients. Here, we present a case of a 25‐year old man infected with the human immunodeficiency virus type‐1 (HIV‐1) who presented with a left‐sided pleural effusion. The cause was confirmed bacteriologically to be due to Salmonella paratyphi. The outcome was favourable after antibiotic therapy coupled with pleural drainage. It should be recognised that pleural empyema due to Salmonella may occur in HIV‐infected subjects and we suggest that patients presenting with pleural empyema due to uncommon pathogens be tested for HIV‐1 antibodies.

Peripheral Blood Mitochondrial DNA Damage as a Potential Noninvasive Biomarker of Diabetic Retinopathy.

Purpose In the development of diabetic retinopathy, retinal mitochondria become dysfunctional, and mitochondrial DNA (mtDNA) is damaged. Because retinopathy is a progressive disease, and circulating glucose levels are high in diabetes, our aim was to investigate if peripheral blood mtDNA damage can serve as a potential biomarker of diabetic retinopathy. Methods Peripheral blood mtDNA damage was investigated by extended-length PCR in rats and mice, diabetic for 10 to 12 months (streptozotocin-induced, type 1 model), and in 12- and 40-week-old Zucker diabetic fatty rats (ZDF, type 2). Mitochondrial copy number (in gDNA) and transcription (in cDNA) were quantified by qPCR. Similar parameters were measured in blood from diabetic patients with/without retinopathy. Results Peripheral blood from diabetic rodents had significantly increased mtDNA damage and decreased copy numbers and transcription. Lipoic acid administration in diabetic rats, or Sod2 overexpression or MMP-9 knockdown in mice, the therapies that prevent diabetic retinopathy, also ameliorated blood mtDNA damage and restored copy numbers and transcription. Although blood from 40-week-old ZDF rats had significant mtDNA damage, 12-week-old rats had normal mtDNA. Diabetic patients with retinopathy had increased blood mtDNA damage, and decreased transcription and copy numbers compared with diabetic patients without retinopathy and nondiabetic individuals. Conclusions Type 1 diabetic rodents with oxidative stress modulated by pharmacologic/genetic means, and type 2 animal model and patients with/without diabetic retinopathy, demonstrate a strong relation between peripheral blood mtDNA damage and diabetic retinopathy, and suggest the possibility of use of peripheral blood mtDNA as a noninvasive biomarker of diabetic retinopathy.