H.W. de Valk

Impaired fatty acid metabolism in familial combined hyperlipidemia. A mechanism associating hepatic apolipoprotein B overproduction and insulin resistance.

To establish whether insulin resistance and/or postprandial fatty acid metabolism might contribute to familial combined hyperlipidemia (FCH) we have examined parameters of insulin resistance and lipid metabolism in six FCH kindreds. Probands and relatives (n = 56) were divided into three tertiles on the basis of fasting plasma triglycerides (TG). Individuals in the highest tertile (TG > 2.5 mM; n = 14) were older and had increased body mass index, systolic blood pressure, and fasting plasma insulin concentrations compared with individuals in the lowest tertile (n = 24). The former also presented with decreased HDL cholesterol and increased total plasma cholesterol, HDL-TG, and apoprotein B, E, and CIII concentrations. Insulin concentrations were positively correlated with plasma apo B, apo CIII, apo E, and TG, and inversely with HDL cholesterol. Fasting nonesterified fatty acids (NEFA) were elevated in FCH subjects compared to six unrelated controls and five subjects with familial hypertriglyceridemia. Prolonged and exaggerated postprandial plasma NEFA concentrations were found in five hypertriglyceridemic FCH probands. In FCH the X2 minor allele of the AI-CIII-AIV gene cluster was associated with increased fasting plasma TG, apo CIII, apo AI, and NEFA concentrations and decreased postheparin lipolytic activities. The clustering of risk factors associated with insulin resistance in FCH indicates a common metabolic basis for the FCH phenotype and the syndrome of insulin resistance probably mediated by an impaired fatty acid metabolism.

Magnesium in diabetes mellitus.

A tendency for magnesium deficiency in patients with diabetes mellitus is well-established. Glucosuria-related hypermagnesiuria, nutritional factors and hyperinsulinaemia-related hypermagnesiuria all can contribute. The plasma magnesium level has been shown to be inversely related to insulin sensitivity. Magnesium supplementation improves insulin sensitivity as well as insulin secretion in patients with type 2 diabetes. Nevertheless, no beneficial effects of oral magnesium supplementation has been demonstrated on glycaemic control either in patients with diabetes type 1 or 2. Oral magnesium supplementation reduced the development of type 2 diabetes in predisposed rats. There are some indications that magnesium decreases blood pressure, but negative results have been observed in trials that were, however, not designed to test effect on blood pressure as primary parameter. Patients with (severe) retinopathy have a lower plasma magnesium level compared to patients without retinopathy and a prospective study has shown the plasma magnesium level to be inversely related to occurrence or progression of retinopathy. Further study on magnesium (supplementation) is warranted in the prevention of type 2 and of (progression of) retinopathy as well as a means to reduce high blood pressure.

Oral magnesium supplementation in insulin-requiring Type 2 diabetic patients.

Oral magnesium (Mg) supplementation can improve insulin sensitivity and secretion in patients with Type 2 diabetes mellitus (DM). We studied the effect of Mg supplementation on glycaemic control, blood pressure, and plasma lipids in insulin‐requiring patients with Type 2 DM. Fifty moderately controlled patients were randomized to 15 mmol Mg or placebo daily for 3 months. Plasma Mg, glucose, HbA1c, lipids, erythrocyte Mg, Mg and glucose concentrations in 24‐h urine, and systolic and diastolic pressure were measured before and after 3 months treatment. Plasma Mg concentration was higher after supplementation than after placebo (0.82 ± 0.07 vs 0.78 ± 0.08 mmol l−1, p<0.05), as was Mg excretion (5.5 ± 1.9 vs 3.7 ± 1.4 mmol 24 h−1, p = 0.004) but erythrocyte Mg concentrations were similar. No significant differences were found in glycaemic control (glucose: 10.7 ± 3.8 vs 11.6 ± 6.2 mmol l−1, p = 0.8; HbA1c: 8.9 ± 1.6 vs 9.1 ± 1.2%, p = 0.8), lipids or blood pressure. On‐treatment analysis (34 patients: 18 on Mg, 16 on placebo) yielded similar results. An increase in plasma Mg concentration irrespective of medication was associated with a tendency to a decrease in diastolic pressure (increased plasma Mg vs no increase: −4.0 ± 10.1 vs +2.5 ± 12.0 mmHg, p = 0.059). Three months’ oral Mg supplementation of insulin‐requiring patients with Type 2 DM increased plasma Mg concentration and urinary Mg excretion but had no effect on glycaemic control or plasma lipid concentrations.

Real-time continuous glucose monitoring system for treatment of diabetes: a systematic review

Diabet. Med. 28, 386–394 (2011)

Estimating the risk of gestational diabetes mellitus: a clinical prediction model based on patient characteristics and medical history

Objective  To develop a clinical prediction rule that can help the clinician to identify women at high and low risk for gestational diabetes mellitus (GDM) early in pregnancy in order to improve the efficiency of GDM screening.

The course of life and quality of life of early and continuously treated Dutch patients with phenylketonuria

SummaryPhenylketonuria (PKU; OMIM 261600) is an autosomal recessive disorder of phenylalanine metabolism caused by a deficiency of the enzyme phenylalanine hydroxylase (PAH; EC 1.14.16.1). Cognitive problems, neuropsychological abnormalities and psychosocial problems have been reported frequently in children and adolescents with PKU, even in those who are treated early and continuously. However, the developmental consequences in adulthood of growing up with PKU are not well known. The aim of this study was to assess the course of life, sociodemographic outcomes and health-related quality of life in young adult patients with PKU identified on neonatal screening who were continuously on treatment. A total of 32 PKU patients 18 to 30 years old completed the Course of Life questionnaire, the RAND-36 Health Survey, and the cognitive scale of the TNO-AZL Adult Quality of Life (TAAQoL) questionnaire. The results of the Course of Life and Health-Related Quality of Life questionnaires were comparable to controls, except that a higher percentage received special education in primary school. Their educational attainment, however, was comparable to that of their peers. The results of this study demonstrate that although PKU is a chronic disease with the burden of strict dietary control, early and continuously treated patients with PKU can have a normal health-related quality of life and course of life.

Sex hormone-binding globulin concentrations before conception as a predictor for gestational diabetes in women with polycystic ovary syndrome

BACKGROUND Low plasma sex hormone-binding globulin (SHBG) concentrations during pregnancy have been associated with the risk of developing gestational diabetes mellitus (GDM). Women presenting with polycystic ovary syndrome (PCOS) often exhibit low plasma SHBG concentration and are at increased risk of developing GDM. In this study, we investigate whether SHBG levels before conception are predictive of GDM in women with PCOS. METHODS A total of 50 women with PCOS were enrolled and followed up during pregnancy. Initial endocrine, metabolic and physical features were assessed according to a standardized preconception screening program. At 24-26 weeks of gestational age a 100-g glucose tolerance test was performed to screen for GDM. RESULTS Of the 50 women, 21 (42%) were diagnosed with GDM by a 100-g glucose tolerance test. Waist circumference, BMI, blood pressure, plasma glucose, insulin, homeostasis model assessment-insulin resistance (HOMA-IR) and SHBG levels before conception were significantly different between women who did and did not develop GDM. Stepwise logistic regression analysis showed that SHBG was the most significant predictive parameter for GDM (odds ratio 0.92; 95% confidence interval 0.87-0.97), without significant contribution of waist circumference and HOMA-IR. Receiver operator characteristic (ROC) analysis indicated that plasma SHBG (area under the curve 0.86) had the highest predictive value for subsequent development of GDM, however, the limited group size did not allow for calculation of a threshold value of SHBG. CONCLUSIONS In women with PCOS, preconception SHBG levels are strongly associated with subsequent development of GDM. Regression and ROC analysis show that preconception SHBG levels may be a better predictor for GDM in PCOS women compared with waist circumference or HOMA-IR. CLINICAL TRIAL REGISTRATION NUMBER NCT00821379.

High Dose of Simvastatin Normalizes Postprandial Remnant-Like Particle Response in Patients With Heterozygous Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) and disturbances in postprandial lipoprotein metabolism are both associated with premature atherosclerosis. The effect of &bgr;-hydroxy-&bgr;-methylglutaryl coenzyme A reductase inhibitors on plasma cholesterol levels in patients with FH is well established; however, it is not known whether postprandial lipoproteins are also influenced. In this case-controlled intervention study, we investigated the effects of high-dose simvastatin on postprandial lipoproteins. We used a new method to analyze remnant lipoproteins based on the immunoseparation principle (remnant-like particle cholesterol [RLP-C] assay) and the well-established measurement of retinyl ester (RE) analysis in plasma and in the Svedberg flotation unit (Sf)<1000 fraction. Seven heterozygous FH patients and 7 control subjects matched for sex, age, body mass index, triglycerides, and apolipoprotein E genotype were enrolled in the study. An oral vitamin A (RE) fat-loading test was performed at baseline in both groups and after 3 months of high-dose simvastatin (80 mg/d) treatment in the FH patients. Before treatment, FH patients had significantly higher fasting and postprandial concentrations of lipoprotein remnants (plasma RLP-C 42±19 mg/dL and area under the RLP-C curve 415±82 mg · L−1 · h−1, respectively) than did control subjects (7±3 mg/dL and 101±35 mg · L −1 · h−1, respectively;P <0.05), suggesting a delayed clearance of chylomicron remnant particles in the FH patients. Treatment with simvastatin significantly reduced fasting and postprandial remnant lipoprotein cholesterol concentrations (13±3 mg/dL and 136±53 mg · L −1 · h−1, respectively;P <0.05 for both). Postprandial RE in the Sf<1000 fraction, not total RE in plasma, was also significantly higher in FH patients than in control subjects (24±10 versus 6.3±5.9 mg · L −1 · h−1, P <0.05), but treatment with simvastatin did not result in improvement of the postprandial RE response, either in the Sf<1000 fraction or in plasma. It is concluded that heterozygous FH patients have increased fasting and postprandial remnant lipoprotein concentrations. Treatment with simvastatin significantly reduced the fasting and postprandial RLP-C concentrations but did not result in improved postprandial RE response.

The Utrecht Diabetes Project: telemedicine support improves GP care in Type 2 diabetes

Introduction The Utrecht Diabetes Project (UDP) is a shared‐care project providing remote diabetologist support for 85 GPs. In the UDP all examinations, performed by the GP, follow standardized procedures, results being sent to the diabetologist. Laboratory results are sent automatically to both GP and diabetologist.

Diabetes before and after lung transplantation in patients with cystic fibrosis and other lung diseases.

Diabet. Med. 29, e159–e162 (2012)