Lea Duvnjak

Relationship between Adiponectin Level, Insulin Sensitivity, and Metabolic Syndrome in Type 1 Diabetic Patients

Objective. Adiponectin is known to be decreased in insulin resistance (IR) and metabolic syndrome (MS) which can be present in patients with type 1 diabetes mellitus (T1DM). The aim of this study was to evaluate the relationship between adiponectin level, MS, and insulin sensitivity in T1DM. Research Design and Methods. The study included 77 T1DM patients divided into two groups based on the total plasma adiponectin median value. Insulin sensitivity was calculated with the equation for eGDR, and MS was defined according to International Diabetes Federation criteria. Results. Patients with higher adiponectin level (n = 39) had significantly lower waist circumference (P < 0.002), fasting venous glucose levels (P < 0.001), higher HDL3-cholesterol (P = 0.011), and eGDR (P = 0.003) in comparison to the group with lower adiponectin who showed higher prevalence of MS (P = 0.045). eGDR increased for 1.09 mg/kg−1 min−1 by each increase of 1 µg/mL total fasting plasma adiponectin (P = 0.003). In the logistic regression model, adiponectin was inversely associated with the presence of MS (P = 0.014). Conclusion. Higher adiponectin concentration is associated with lower prevalence of MS in T1DM. Whether higher adiponectin concentration has a protective role in the development of the MS in T1DM needs to be clarified in future follow-up studies.

Relationship between autonomic function, 24-h blood pressure, and albuminuria in normotensive, normoalbuminuric patients with Type 1 diabetes

We performed a battery of cardiovascular reflex tests, 24-h ambulatory blood pressure (AMBP) and 24-h urinary albumin excretion (UAE) in 116 normoalbuminuric and normotensive patients with Type 1 diabetes. Tests of heart rate variation (HRV) included the coefficient of variation (CV) and the low-frequency (LF), mid-frequency (MF), and high-frequency (HF) bands of spectral analysis at rest, HRV during deep breathing (CV, mean circular resultant--MCR), Valsalva ratio, and maximum/minimum 30:15 ratio. Autonomic neuropathy, characterized as an abnormality of more than two tests, was found in 33 patients. Patients with neuropathy compared to those without neuropathy showed significantly higher mean day and night diastolic blood pressure (dBP), mean systolic night blood pressure (sBP), and mean day and night heart rate (HR). Mean night dBP was inversely related to MF, HF, and HRV during deep breathing; mean day dBP and mean night sBP to HF; mean night HR to CV at rest, MF, HF, HRV during deep breathing, 30:15 ratio; mean day HR to HF, HRV during deep breathing, Valsalva, and 30:15 ratio. Mean 24-h UAE was not significantly different in neuropathic than in nonneuropathic patients. UAE was inversely related to CV at rest and HF. In the stepwise multiple regression analysis, reduced MF, HF, HRV during deep breathing, and high levels of UAE and HbA1c were associated with high night dBP. Autonomic neuropathy is already present in normotensive Type 1 diabetic patients at the normoalbuminuric stage and related to BP and albuminuria.

Incretin based therapies:A novel treatment approach for non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease is considered a hepatic manifestation of metabolic syndrome (MS). The current treatment of non-alcoholic fatty liver disease (NAFLD) principally includes amelioration of MS components by lifestyle modifications but the lack of success in their implementation and sustainment arises the need for effective pharmacological agent in fatty liver treatment. Incretins are gut derived hormones secreted into the circulation in response to nutrient ingestion that enhances glucose-stimulated insulin secretion. Glucagon-like peptide-1 (GLP-1) is the most important incretin. Its receptor agonist and inhibitors of dipeptidyl peptidase-4 (DPP-4) are used in treatment of type 2 diabetes mellitus. DPP-4 serum activity and hepatic expression are shown to be elevated in several hepatic diseases. There are several experimental and clinical trials exploring the efficacy of incretin based therapies in NAFLD treatment. They suggest that GLP-1 analogues might have beneficial effect on hepatic steatosis acting as insulin sensitizers and directly by stimulating GLP-1 receptors expressed on hepatocytes. The use of DPP-4 inhibitors also results in hepatic fat reduction but the mechanism of action remains unclear. There is growing evidence that incretin based therapies have beneficial effects on hepatocytes, however further study analysis are needed to assess the long term effect of incretin based therapies on NAFLD.

The effect of alpha-linolenic acid on glycemic control in individuals with type 2 diabetes: A systematic review and meta-analysis of randomized controlled clinical trials.

Background: Polyunsaturated fats (PUFAs) have been shown to reduce type 2 diabetes (T2DM) risk and improve insulin responsiveness in T2DM subjects, but whether the plant sources of omega-3 PUFA (alpha-linolenic acid [ALA]) have an effect on glycemic control requires further investigation. Methods: The parameters of interest were glycated hemoglobin (HbA1c), fasting blood glucose (FBG), fasting blood insulin (FBI), homeostatic model assessment for insulin resistance (HOMA-IR), fructosamine, and glycated albumin. A comprehensive search was conducted with MEDLINE, Embase, CINAHL, and Cochrane. Eligible studies included randomized controlled trials (RCTs) ≥1 month in duration that compared diets enriched in ALA with usual diets on glycemic parameters. For each study, the risk of bias as well as the study quality was assessed. Using the statistical software RevMan (v5.3), data were pooled using the generic inverse method with random effects model, and final results were expressed as mean differences (MD) with 95% confidence intervals (CI). Heterogeneity was assessed by the Cochran Q statistic and quantified by the I2 statistic. Results: A total of 8 trials (N = 212) were included in the meta-analysis. Compared to a control diet, a median dose of 4.4 g/day of ALA intake for a median duration of 3 months did not affect HbA1c (%) (MD = –.01; [95%: –.32, .31], P = .96). A median ALA dose of 5.4 g/day did not lower FBG (MD = .07; [95% CI: –.61, .76], P = .84) or FBI (MD = 7.03, [95% CI: –5.84, 19.89], P = .28). Summary effect estimates were generally compromised by considerable and unexplained heterogeneity (I2 ≥75%). In the subgroup analysis of continuous predictors, a reduction in HbA1c (%) and FBG (mmol/L) was significantly associated with an increased intake of ALA. Further adjustment for Publication Bias using Duval and Tweedies trim-and-fill analysis provided an adjusted, significant MD of –.25 (95% CI: –.38, –.12; P <.001) for HbA1c (%). Conclusions: ALA-enriched diets did not affect HbA1c, FBG, or FBI. The scarce number of existing RCTs and the presence of heterogeneity in our meta-analysis limit the ability to make firm conclusions about ALA in T2DM management. The potential for ALA to have dose-dependent effects warrants further research in this area.

Circulating dipeptidyl peptidase-4 activity is associated with insulin resistance in type 1 diabetic patients

AIM The pathophysiology of insulin resistance (IR) comprises a complex adipokine mediated cross-talk between white adipose tissue and other organs. Dipeptidyl peptidase-4 (DPP4) is protease recently proposed as a novel adipokine linked to IR. We aimed to assess the relationship between fasting serum DPP4 activityand IR in type 1 diabetic (T1DM) patients. METHODS A cross-sectional study comprised 44 T1DM patients aged >18 and <65years. IR was esimated using the equation for insulin sensitivity derived from euglycemic-hyperinsulinemic clamp studies-estimated glucose disposal rate (eGDR). DPP4 serum activity was determined spectrophotometrically as a rate of cleavage of 7-Amino-4-Methyl Coumarin (AMC) from H-Gly-Pro-AMC. RESULTS Patients were divided according to DPP4 activity tertiles (<25.40; ≥36.54 U/L). Fasting serum DPP4 activity was related to disease duration (p=0.012), systolic (p=0.009) and diastolic (p=0.047) blood pressure, waist circumference (p=0.037), urine albumin excretion (p=0.022) and conversely related to eGDR (p=0.004). The linear regression has shown that eGDR decreases for 0.203 mgkg(-1)min(-1) by each increase of serum DPP4 activity of 1 U/L (p<0.001) after adjustment for adjusted for age, gender, disease duration, albuminuria and the use of antihypertensives and statins. CONCLUSION Serum DPP4 activity is associated with IR in T1DM patients and it might play an important role in its pathophysiology.

Alkaline phosphatase is independently associated with renal function in normoalbuminuric type 1 diabetic patients.

Abstract Nonalcoholic fatty liver disease (NAFLD) is associated with an increased prevalence of chronic kidney disease in patients with type 1 diabetes. The aim of this study was to explore the relationship between markers of NAFLD, namely concentrations of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALK), γ-glutamyltransferase (GGT), bilirubin, and renal function in type 1 diabetic patients. This study included 313 normoalbuminuric type 1 diabetic patients with estimated glomerular filtration rate (eGFR) >60 mL/min/1.73 m2, without clinical evidence of cirrhosis or other causes of chronic liver disease and before any interventions with statins, angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers. ALT, GGT, and bilirubin levels were significantly higher in subjects in the highest quartile of serum creatinine compared to those in lowest quartile (21 vs. 20 U/L, 18 vs. 14 U/L, and 14 vs. 10 µmol/L, respectively, for all p < 0.05). ALK levels were significantly higher in subjects in the highest quartile of urinary albumin excretion rate compared to those in lowest quartile (71 vs. 69 U/L, p = 0.03), as well as in hyperfiltrating subjects compared to those with normal or mildly impaired eGFR (81 vs. 68 and 64 U/L, p < 0.001). In a multiple logistic regression model adjusted for age, sex, duration of diabetes, HbA1c, and body mass index (BMI), only ALK levels were significantly associated with disturbances in serum creatinine and eGFR in our subjects (p ≤ 0.007), with odds ratios of 0.98–1.02. NAFLD associated markers, particularly ALK, are associated with renal function in normoalbuminuric type 1 diabetic patients.

Lower levels of total HDL and HDL3 cholesterol are associated with albuminuria in normoalbuminuric Type 1 diabetic patients

Background: Previous studies have suggested a positive association between dyslipidemia and chronic kidney disease, but sparse data are available on the relation of lipids and urinary albumin excretion rate (UAE) in normoalbuminuric patients with normal renal function. Aim: The aim of this study was to evaluate the associations of serum lipids, including total, LDL, HDL, HDL2, HDL3 cholesterol, and triglyceride levels with UAE in normoalbuminuric Type 1 diabetic (T1D) patients. Methods: Study included 313 normoalbuminuric T1D patients with normal renal function and before any interventions with statins, ACE inhibitors or angiotensin II receptor blockers. Subjects were classified as low-normoalbuminuric (UAE<11.0 mg/24h) or high-normoalbuminuric (UAE≥11.0 mg/24h) based on median UAE of at least two 24-h urine collections. Correlations and multiple linear regressions analysis were performed to identify relationships between serum lipids and UAE in normoalbuminuric subjects. Results: Total HDL (p=0.02) and HDL3 cholesterol (p=0.01) levels were higher in low-normoalbuminuric subjects compared to high-normoalbuminuric subjects. In logistic regression analysis, after adjustment for age, sex, BMI, duration of diabetes and HbA1c, lower total HDL and HDL3 cholesterol levels were significantly associated with risk of higher UAE in our normoalbuminuric subjects (p≤0.01), with odds ratios of 0.34 to 0.43. Conclusions: Elevated total HDL and HDL3 cholesterol levels are associated with lower UAE in normoalbuminuric T1D patients. However, whether the detection of elevated total HDL and HDL3 cholesterol levels in T1D patients has protective value for development of microalbuminuria needs to be assessed in further follow-up studies.

A systematic review and meta-analysis of randomized controlled trials of the effect of konjac glucomannan, a viscous soluble fiber, on LDL cholesterol and the new lipid targets non-HDL cholesterol and apolipoprotein B

Background: Evidence from randomized controlled trials (RCTs) suggests the consumption of konjac glucomannan (KJM), a viscous soluble fiber, for improving LDL-cholesterol concentrations. It has also been suggested that the cholesterol-lowering potential of KJM may be greater than that of other fibers. However, trials have been relatively scarce and limited in sample size and duration, and the effect estimates have been inconsistent. The effect of KJM on new lipid targets of cardiovascular disease (CVD) risk is also unknown.Objective: This systematic review and meta-analysis aimed to assess the effect of KJM on LDL cholesterol, non-HDL cholesterol, and apolipoprotein B.Design: Medline, Embase, CINAHL, and the Cochrane Central databases were searched. We included RCTs with a follow-up of ≥3 wk that assessed the effect of KJM on LDL cholesterol, non-HDL cholesterol, or apolipoprotein B. Data were pooled by using the generic inverse-variance method with random-effects models and expressed as mean differences (MDs) with 95% CIs. Heterogeneity was assessed by the Cochran Q statistic and quantified by the I2 statistic.Results: Twelve studies (n = 370), 8 in adults and 4 in children, met the inclusion criteria. KJM significantly lowered LDL cholesterol (MD: -0.35 mmol/L; 95% CI: -0.46, -0.25 mmol/L) and non-HDL cholesterol (MD: -0.32 mmol/L; 95% CI: -0.46, -0.19 mmol/L). Data from 6 trials suggested no impact of KJM on apolipoprotein B.Conclusions: Our findings support the intake of ∼3 g KJM/d for reductions in LDL cholesterol and non-HDL cholesterol of 10% and 7%, respectively. The information may be of interest to health agencies in crafting future dietary recommendations related to reduction in CVD risk. This study was registered at clinicaltrials.gov as NCT02068248.

Efficacy of lixisenatide in patients with type 2 diabetes: A post hoc analysis of patients with diverse β-cell function in the GetGoal-M and GetGoal-S trials

AIMS To evaluate the impact of β-cell function on the efficacy of lixisenatide, a once-daily prandial glucagon-like peptide-1 receptor agonist, in patients with type 2 diabetes (T2D). MATERIALS AND METHODS In this post hoc analysis, patients from the Phase 3 GetGoal-M and GetGoal-S clinical trials randomized to lixisenatide 20μg once daily were stratified into quartiles by baseline β-cell function, as measured by the secretory units of islet in transplantation (SUIT) index. RESULTS Patients (N=437) were distributed evenly among SUIT index quartiles 1 to 4 (lowest to highest β-cell function). Clinical outcomes improved from baseline across all SUIT quartiles; mean changes at week 24 were: glycated hemoglobin (HbA1c; % [mmol/mol]), -0.99 (-10.8), -0.87 (-9.5), -0.86 (-9.4), -0.83 (-9.1); and postprandial plasma glucose (PPG; mmol/L), -7.9, -5.6, -5.5, -4.3 (overall effect P<0.0001). Furthermore, postprandial glucagon was reduced in all SUIT quartiles, while insulinogenic index improved only in patients with higher baseline SUIT (overall effect P=0.0286). No severe symptomatic hypoglycemic events were reported. CONCLUSIONS Lixisenatide treatment resulted in reductions in HbA1c and PPG levels across all SUIT quartiles. This suggests that non-insulin-related actions of lixisenatide contribute to improved glycemic control in T2D.

The effect of ginseng (genus Panax) on blood pressure: a systematic review and meta-analysis of randomized controlled clinical trials.

Pre-clinical evidence indicates the potential for ginseng to reduce cardiovascular disease risk and acutely aid in blood pressure (BP) control. Clinical evidence evaluating repeated ginseng exposure, however, is controversial, triggering consumer and clinician concern. A systematic review and meta-analysis were conducted to assess whether ginseng has an effect on BP. MEDLINE, EMBASE, Cochrane and CINAHL were searched for relevant randomized controlled trials ⩾4 weeks that compared the effect of ginseng on systolic (SBP), diastolic (DBP) and/or mean arterial (MAP) BPs to control. Two independent reviewers extracted data and assessed methodological quality and risk of bias. Data were pooled using random-effects models and expressed as mean differences (MD) with 95% confidence intervals (CIs). Heterogeneity was assessed and quantified. Seventeen studies satisfied eligibility criteria (n=1381). No significant effect of ginseng on SBP, DBP and MAP was found. Stratified analysis, although not significant, appears to favour systolic BP improvement in diabetes, metabolic syndrome and obesity (MD=−2.76 mm Hg (95% CI=−6.40, 0.87); P=0.14). A priori subgroup analyses revealed significant association between body mass index and treatment differences (β=−0.95 mm Hg (95% CI=−1.56, −0.34); P=0.007). Ginseng appears to have neutral vascular affects; therefore, should not be discouraged for concern of increased BP. More high-quality, randomized, controlled trials assessing BP as a primary end point, and use of standardized ginseng root or extracts are warranted to limit evidence of heterogeneity in ginseng research and to better understand its cardiovascular health potential.