Aims/hypothesis Characterisation of genetic variation that influences the response to glucose-lowering medications is instrumental to precision medicine for treatment of type 2 diabetes. The Study... Show moreAims/hypothesis Characterisation of genetic variation that influences the response to glucose-lowering medications is instrumental to precision medicine for treatment of type 2 diabetes. The Study to Understand the Genetics of the Acute Response to Metformin and Glipizide in Humans (SUGAR-MGH) examined the acute response to metformin and glipizide in order to identify new pharmacogenetic associations for the response to common glucose-lowering medications in individuals at risk of type 2 diabetes.Methods One thousand participants at risk for type 2 diabetes from diverse ancestries underwent sequential glipizide and metformin challenges. A genome-wide association study was performed using the Illumina Multi-Ethnic Genotyping Array. Imputation was performed with the TOPMed reference panel. Multiple linear regression using an additive model tested for association between genetic variants and primary endpoints of drug response. In a more focused analysis, we evaluated the influence of 804 unique type 2 diabetes- and glycaemic trait-associated variants on SUGAR-MGH outcomes and performed colocalisation analyses to identify shared genetic signals.Results Five genome-wide significant variants were associated with metformin or glipizide response. The strongest association was between an African ancestry-specific variant (minor allele frequency [MAF(Afr)]=0.0283) at rs149403252 and lower fasting glucose at Visit 2 following metformin (p=1.9x10(-9)); carriers were found to have a 0.94 mmol/l larger decrease in fasting glucose. rs111770298, another African ancestry-specific variant (MAF(Afr)=0.0536), was associated with a reduced response to metformin (p=2.4x10(-8)), where carriers had a 0.29 mmol/l increase in fasting glucose compared with non-carriers, who experienced a 0.15 mmol/l decrease. This finding was validated in the Diabetes Prevention Program, where rs111770298 was associated with a worse glycaemic response to metformin: heterozygous carriers had an increase in HbA(1c) of 0.08% and non-carriers had an HbA(1c) increase of 0.01% after 1 year of treatment (p=3.3x10(-3)). We also identified associations between type 2 diabetes-associated variants and glycaemic response, including the type 2 diabetes-protective C allele of rs703972 near ZMIZ1 and increased levels of active glucagon-like peptide 1 (GLP-1) (p=1.6x10(-5)), supporting the role of alterations in incretin levels in type 2 diabetes pathophysiology.Conclusions/interpretation We present a well-phenotyped, densely genotyped, multi-ancestry resource to study gene-drug interactions, uncover novel variation associated with response to common glucose-lowering medications and provide insight into mechanisms of action of type 2 diabetes-related variation. Show less
Background: Multiple preclinical studies have highlighted AMP-activated protein kinase (AMPK) as a potential therapeutic target for autosomal dominant polycystic kidney disease (ADPKD). Both... Show moreBackground: Multiple preclinical studies have highlighted AMP-activated protein kinase (AMPK) as a potential therapeutic target for autosomal dominant polycystic kidney disease (ADPKD). Both metformin and canagliflozin indirectly activate AMPK by inhibiting mitochondrial function, while salsalate is a direct AMPK activator. Metformin, canagliflozin and salsalate (a prodrug dimer of salicylate) are approved for clinical use with excellent safety profile. Although metformin treatment had been shown to attenuate experimental cystic kidney disease, there are concerns that therapeutic AMPK activation in human kidney might require a higher oral metformin dose than can be achieved clinically.Methods: In this study, we tested metformin-based combination therapies for their additive (metformin plus canagliflozin) and synergistic (metformin plus salsalate) effects and each drug individually in an adult-onset conditional Pkd1 knock-out mouse model (n = 20 male/group) using dosages expected to yield clinically relevant drug levels.Findings: Compared to untreated mutant mice, treatment with salsalate or metformin plus salsalate improved kidney survival (i.e. blood urea nitrogen <20 mmol/L at the time of sacrifice) and reduced cystic kidney disease severity. However, the effects of metformin plus salsalate did not differ from salsalate alone; and neither metformin nor canagliflozin was effective. Protein expression and phosphorylation analyses indicated that salsalate treatment was associated with reduction in mTOR (mammalian target of rapamycin) activity and cellular proliferation in Pkd1 mutant mouse kidneys. Global gene expression analyses suggested that these effects were linked to restoration of mitochondrial function and suppression of inflammation and fibrosis.Interpretation: Salsalate is a highly promising candidate for drug repurposing and clinical testing in ADPKD. (C) 2019 The Authors. Published by Elsevier B.V. Show less
Childhood obesity is an increasing health issue. In the first part of this thesis comorbidities in children with obesity were studied, concerning the diagnostic process and dosing regimens. In... Show moreChildhood obesity is an increasing health issue. In the first part of this thesis comorbidities in children with obesity were studied, concerning the diagnostic process and dosing regimens. In children with obesity and respiratory symptoms the diagnosis of asthma was studied and in children with ADHD dosing regimens. Overtreatment as a consequence of overdiagnosis was frequently observed in children with obesity and asthma and undertreatment due to relative underdosing in the ADHD population with obesity. This highlights the necessity for accurate diagnostic processes alongside dosing regimens based on pharmacokinetic changes caused by obesity. The focus in the second part of this thesis was on screening for complications of obesity namely insulin resistance and cardiovascular diseases. Given the high prevalence of insulin resistance and the observed changes of cardiovascular parameters, screening on cardiometabolic complications is warranted in all children with obesity. Pharmacological treatment with metformin in addition to lifestyle intervention was studied in the last part of this thesis. Given the favorable effect on BMI in children and adults and the maintenance of weight loss and reduction in progression towards T2DM in adults, metformin can be considered in children with obesity and insulin resistance in addition to lifestyle intervention. Show less
Molen, A.J. van der; Reimer, P.; Dekkers, I.A.; Bongartz, G.; Bellin, M.F.; Bertolotto, M.; ... ; Thomsen, H.S. 2018
Prevalence of childhood obesity is increasing. Insulin resistance is a consequence of childhood obesity, and it has a keyrole in the development of cardiometabolic complications, such as... Show more Prevalence of childhood obesity is increasing. Insulin resistance is a consequence of childhood obesity, and it has a keyrole in the development of cardiometabolic complications, such as diabetes mellitus. In the first part of this thesis, the epidemiology of insulin resistance has been described. Since there is no clear definition for insulin resistance, the prevalence of IR remains unclear. In addition, the use of IR in the screening for diabetes mellitus in obese children was evaluated. In the second part of the thesis, treatment of obese children with insulin resistance is discussed. In a randomized controlled trial of 18 months, children were treated with either metformin or placebo in addition to lifestyle intervention. Body mass index in children treated with metformin remained stable during the 18 months, whereas placebo-treated children had an increase in body mass index. Finally, the treatment with metformin under the strict circumstances of the clinical trial was compared to treatment with metformin in daily practice during 18 months. Both groups showed similar results regarding body mass index during metformin treatment. Show less
Despite the increasing number of obese patients, evidence-based dosing guidelines are scarce, particularly for obese children and morbidly obese adults (BMI > 40 kg/m2). For both these... Show more Despite the increasing number of obese patients, evidence-based dosing guidelines are scarce, particularly for obese children and morbidly obese adults (BMI > 40 kg/m2). For both these populations, pharmacokinetic studies are needed to provide a basis for evidence-based dosing guidelines. In this thesis, we studied the pharmacokinetics of the CYP3A substrate midazolam, the renally excreted drug metformin and acetaminophen (metabolized by glucuronidation, sulphation and CYP2E1) in obese adolescents and/or morbidly obese adults. We address several currently unanswered questions; Can doses for obese adolescents be predicted on the basis of data obtained in morbidly obese adults? How to analyse pharmacokinetic data in obese adolescents, for whom body weight is influenced by growth, age and obesity? How to achieve safe and effective acetaminophen dosing for morbidly obese patients? The studies described in this thesis contribute to the existing gaps in knowledge regarding the pharmacokinetics and evidence-based dosing of drugs in obese adolescents and morbidly obese adults. Show less
Background and purpose: The aim was to investigate whether the use of metformin during concurrent chemoradiotherapy (cCRT) for locally advanced non-small cell lung cancer (NSCLC) improved treatment... Show moreBackground and purpose: The aim was to investigate whether the use of metformin during concurrent chemoradiotherapy (cCRT) for locally advanced non-small cell lung cancer (NSCLC) improved treatment outcome.Material and methods: A total of 682 patients were included in this retrospective cohort study (59 metformin users, 623 control patients). All received cCRT in one of three participating radiation oncology departments in the Netherlands between January 2008 and January 2013. Primary endpoint was locoregional recurrence free survival (LRFS), secondary endpoints were overall survival (OS), progression-free survival (PFS) and distant metastasis free survival (DMFS).Results: No significant differences in LRFS or OS were found. Metformin use was associated with an improved DMFS (74% versus 53% at 2 years; p = 0.01) and PFS (58% versus 37% at 2 years and a median PFS of 41 months versus 15 months; p = 0.01). In a multivariate cox-regression analysis, the use of metformin was a statistically significant independent variable for DMFS and PFS (p = 0.02 and 0.03).Conclusions: Metformin use during cCRT is associated with an improved DMFS and PFS for locally advanced NSCLC patients, suggesting that metformin may be a valuable treatment addition in these patients. Evidently, our results merit to be verified in a prospective trial. (C) 2016 Elsevier Ireland Ltd. All rights reserved. Show less
This thesis describes the role of the brain in the regulation of peripheral triglyceride metabolism, in the context of the metabolic syndrome. Based on various pharmacological studies we described... Show moreThis thesis describes the role of the brain in the regulation of peripheral triglyceride metabolism, in the context of the metabolic syndrome. Based on various pharmacological studies we described the role of two hormones, insulin and glucagon-like peptide-1, in the production and clearance of triglycerides. We showed that insulin stimulates the uptake of (triglyceride-derived) fatty acids and that the brain plays an essential role in this process. Additionally, we showed that the glucagon-like peptide-1 receptor analogue exendin-4 decreases triglyceride production by the liver, albeit that the brain does not seem to be involved in this effect. Furthermore, we unraveled the mechanism underlying the effects of metformin, the first-line drug used to treat Type 2 Diabetes, on triglyceride metabolism. We showed that metformin lowers plasma triglyceride levels by stimulating the uptake and subsequent oxidation of triglycerides by the brown adipose tissue, and herewith provided new therapeutical opportunities for this drug. Finally, we showed that apolipoprotein A5, a stimulator of triglyceride hydrolysis and subsequent clearance from the plasma, plays a role in the central regulation of food intake, and herewith described a novel function for this apolipoprotein. Show less
