Michael Dennis Jensen

Michael Dennis Jensen
Mayo Foundation for Medical Education and Research | MMS · College of Medicine

MD

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453
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Introduction
Skills and Expertise

Publications

Publications (453)
Article
Context The impact of insulin, particularly exogenous hyperinsulinemia, on insulin secretion in humans is debated. Objective We assessed the effects of exogenous hyperinsulinemia on insulin secretion and whether the response is altered in insulin resistance associated with obesity. Methods Insulin secretion rates (ISR) during euglycemic hyperinsu...
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Objective: Elevated fasting free fatty acids (FFA) are associated with Impaired Glucose Tolerance (IGT) and decreased β-cell function (quantified as Disposition Index (DI)). We sought to examine how changes in fasting FFA and glucose alter islet function. Methods: We studied 10 subjects with Normal Fasting Glucose (NFG) and Normal Glucose Tolera...
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We investigated the relationships between ceramide species concentrations in liver, plasma and very low-density lipoproteins (VLDL) particles of humans with obesity as well as the relationships between hepatic fat content and hepatic ceramide concentrations and proportional distribution. Twenty-five obese (body mass index >35 kg/m2 ) adults partici...
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Objective: Obesity and upper-body fat elevates cardiometabolic risk. However, mechanisms predisposing to upper-body fat accumulation are not completely understood. In males, low testosterone (T) frequently associates with obesity, and estrogen deficiency may contribute to upper-body adiposity. This study examines the effects of overfeeding-induced...
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The role of adipose tissue (AT) inflammation on AT function in humans is unclear. We tested whether AT macrophage (ATM) content, cytokine gene expression and senescent cell burden (markers of AT inflammation) predict AT insulin resistance measured as the insulin concentration that suppresses lipolysis by 50% (IC5). We studied 86 volunteers with nor...
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Aims/hypothesis Early famine exposure has been related to the development of type 2 diabetes; however, little is known about whether the genetic background modifies this association. We aimed to investigate the joint effects of famine exposure at different stages of early life and genetic susceptibility on diabetes risk in adulthood. Methods The s...
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Objective Adipose tissue (AT) senescence is associated with AT dysfunction in rodents, but little is known about human AT senescence. The study goal was to define the distribution of senescent cells in two subcutaneous depots and understand relationships with adiposity and inflammation. Methods Sixty-three volunteers (48 females) underwent abdomin...
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Obesity is accompanied by numerous systemic and tissue-specific derangements, including systemic inflammation, insulin resistance, and mitochondrial abnormalities in skeletal muscle. Despite growing recognition that adipose tissue dysfunction plays a role in obesity-related disorders, the relationship between adipose tissue inflammation and other p...
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Objective: This study tested whether substrate concentrations or fatty acid storage proteins predict storage of endogenous lipids in visceral adipose tissue (VAT) and upper body subcutaneous adipose tissue (UBSQ) fat. Methods: The day prior to surgery, 25 patients undergoing bariatric procedures received an infusion of autologous [1-14 C]triolei...
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Background: Adipose tissue inflammation is linked to adipose tissue insulin resistance. However, whether this is a causal relationship remains controversial. Therefore, we aimed to explore the relationship between measures of adipose tissue inflammation and adipose tissue insulin sensitivity over a wide range of body fat distribution and adipose ti...
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Background: Studies of changes in adipose tissue (AT) inflammation after weight loss have conflicting results. Our aim was to evaluate the changes in AT macrophages, senescence and AT insulin resistance after weight loss. Methods: Twenty-five participants (18 women) with obesity underwent a lifestyle intervention weight loss program and abdominal-f...
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In this article, a re-analysis of the raw data has been conducted, which means that some conclusions presented in the paper have changed. The authors have written a Corrigendum which is appended (Appendix 1). In the interests of transparency, they have included de-identified data from the original article in Appendix 2.
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Palmitoleic acid has been classified as an insulin‐sensitizing lipokine, but evidence for this from human studies has been inconsistent. We hypothesized that this is related to either the types of samples or conditions under which samples are collected. We measured plasma palmitoleic acid and total free fatty acids (FFA) using ultra‐performance liq...
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Background: Senescent cells, which can release factors that cause inflammation and dysfunction, the senescence-associated secretory phenotype (SASP), accumulate with ageing and at etiological sites in multiple chronic diseases. Senolytics, including the combination of Dasatinib and Quercetin (D + Q), selectively eliminate senescent cells by transi...
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Purpose Nonalcoholic fatty liver disease can lead to hepatic inflammation/damage. Understanding the physiological mechanisms that contribute to excess hepatic lipid accumulation may help identify effective treatments. Methods We recruited 25 severely obese, non-diabetic patients scheduled for bariatric surgery. To evaluate liver export of triglyce...
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Background: The AspireAssist is the first Food and Drug Administration-approved endoluminal device indicated for treatment of class II and III obesity. Objectives: We earlier reported 1-year results of the PATHWAY study. Here, we report 4-year outcomes. Setting: United States-based, 10-center, randomized controlled trial involving 171 particip...
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Background Increases in circulating free‐fatty acids (FFAs) contribute to obesity‐associated cardiometabolic pathology and may be considered a surrogate marker for adipose tissue dysfunction. However, alterations in FFA metabolism resulting from modest weight gain have not been previously evaluated. Objective Examine the changes in FFAs during mod...
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Adipose tissue inflammation and dysfunction are associated with obesity‐related insulin resistance and diabetes, but mechanisms underlying this relationship are unclear. Although senescent cells accumulate in adipose tissue of obese humans and rodents, a direct pathogenic role for these cells in the development of diabetes remains to be demonstrate...
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Background: Serum concentrations of fatty acid binding protein 4, an adipose tissue fatty acid chaperone, have been correlated with insulin resistance and cardiovascular risk factors. The objective of this study were to assess relationships among Roux-en-Y gastric bypass, intensive lifestyle modification and medical management protocol, fatty acid...
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Context Previous epidemiological studies had inconsistent results regarding the relationship between blood lead level (BLL) and adiposity. Objective We aimed to investigate the associations of BLL with body mass index (BMI) particularly using mendelian randomization analyses and examine the interaction between obesity-predisposing genes and BLL on...
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Objective: To examine whether experimentally induced weight gain raises ambulatory blood pressure (BP) in healthy subjects and identify any relationship between changes in BP and changes in regional fat distribution. Patients and methods: Twenty-six normal weight subjects were randomized to 8 weeks of weight gain through overfeeding (n=16; age,...
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Elevations in both plasma free fatty acids (FFA) and glucose concentrations during fasting are associated with impaired β-cell function and predict progression from prediabetes to diabetes. Their interaction and subsequent effect on β-cell function as quantified by Disposition Index (DI) is unknown. We therefore measured total, saturated, mono-unsa...
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Objective: The relationship between inflammation, obesity, and adverse metabolic conditions is associated with adipose tissue macrophages (ATM). This study compared the measurements of human ATM using flow cytometry, immunohistochemistry (IHC), and real-time polymerase chain reaction (RT-PCR) of ATM markers. Methods: A new software program (AMCo...
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We investigated the effects of meal ingestion on intramyofibrillar (IMF) and subsarcolemmal (SS) ceramide metabolism in volunteers ranging from lean to obese. Thirty-eight women and men underwent a steady-state meal ingestion protocol that included a 6.5 h infusion of [U-(13)C] palmitate and muscle biopsies 1.5 h and 6.5 h after starting the tracer...
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Background Type 2 diabetes is associated with excess postprandial lipemia due to accumulation of chylomicrons and VLDL particles. This is a risk factor for development of cardiovascular disease. However, whether the excess lipemia is associated with an impaired suppression of VLDL-TG secretion and/or reduced clearance into adipose tissue is unknown...
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Context Although the long-term effects of testosterone on adipose tissue lipid metabolism in men have been defined, the short-term regulation of these effects is not well understood. Objective We examined the effects of acute testosterone withdrawal on subcutaneous abdominal and femoral adipose tissue fatty acid (FA) storage and cellular mechanism...
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We investigated the relationship between insulin resistance markers and subsarcolemmal (SS) and intramyofibrillar (IMF) ceramide concentrations, as well as the contribution of plasma palmitate (6.5 h infusion of [U-(13)C]palmitate) to intramyocellular ceramides. Seventy-six postabsorptive men and women had muscle biopsies 1.5 h, 6.5 h and 24 h afte...
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Background: The purpose of this study is to compare effects of different nations on Roux-en-Y gastric bypass (RYGB) vs. intensive medical management (IMM) in achieving remission of type 2 diabetes mellitus (T2DM). Materials and methods: Between April 2008 and December 2011, this randomized, controlled clinical trial was conducted at four teachin...
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Background: Increased omega-3 (n-3) fatty acid consumption is reported to benefit patients with metabolic syndrome, possibly due to improved adipose tissue function.Objective:We tested the effects of high-dose, very-long-chain ω-3 fatty acids on adipose tissue inflammation and insulin regulation of lipolysis.Design:A double-blind, placebo-controlle...
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Aims/hypothesis: Limited studies have compared the effect of prenatal or postnatal exposure to different severities of famine on the risk of developing diabetes. We aimed to measure the association between diabetes in adulthood and the exposure to different degrees of famine early in life (during the prenatal or postnatal period) during China's Gr...
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Background: Adipose tissue insulin resistance may be a proximate cause of hepatic and skeletal muscle insulin resistance by releasing excess FFA. However, no consensus exists on how to quantify adipose tissue insulin sensitivity. We compared three methods for measuring adipose tissue insulin sensitivity ranging from the complex multistep pancreati...
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Objectives: The AspireAssist System (AspireAssist) is an endoscopic weight loss device that is comprised of an endoscopically placed percutaneous gastrostomy tube and an external device to facilitate drainage of about 30% of the calories consumed in a meal, in conjunction with lifestyle (diet and exercise) counseling. Methods: In this 52-week cl...
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Objective: TCF7L2 variant rs7903146 is associated with increased risk for type 2 diabetes. We investigated the effect of TCF7L2 variant rs7903146 and glucose tolerance on free fatty acid (FFA) metabolism. Research design and methods: We recruited 120 individuals, half homozygous for the major CC allele and half homozygous for the minor TT allele...
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Context: Lipoprotein lipase (LPL) activity is considered the rate-limiting step of very-low-density-lipoprotein triglycerides (VLDL-TG) tissue storage, and has been suggested to relate to the development of obesity as well as insulin resistance and type 2 diabetes. Objective: The objective of the study was to assess the relationship between the...
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A recent editorial in the Journal of Clinical Investigation by Nathan et al. (1) dwelt on the decision to cease direct National Institutes of Health (NIH) funding of Clinical Research Centers (CRCs). As the authors rightly point out, the lack of extramural support for the CRC infrastructure will doom this valuable resource for human research at aca...
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The aim of this study is to evaluate blood cadmium levels (BCLs) in Chinese adults and explore whether blood cadmium is associated with diabetes or obesity. This study included 5544 adults from a cross-sectional SPECT-China study. BCL and blood lead level (BLL) was measured by atomic absorption spectrometry. Fasting plasma glucose (FPG) was used to...
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Background: Some previous studies have indicated that a low basal metabolic rate (BMR) is an independent predictor of future weight gain, but low rates of follow-up and highly select populations may limit the ability to generalize the results. Objective: We assessed whether adults with a low BMR gain more weight than do adults with a high BMR wh...
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Some studies indicate that basal metabolic rate is greater in winter than in the summer, suggesting a role for brown fat in human thermogenesis. We examined whether there are clinically meaningful differences in basal metabolic rate under thermoneutral conditions between winter and summer months in inhabitants of Rochester, Minnesota. We collated d...
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Objective: We compared 3-year achievement of an American Diabetes Association composite treatment goal (HbA1c <7.0%, LDL cholesterol <100 mg/dL, and systolic blood pressure <130 mmHg) after 2 years of intensive lifestyle-medical management intervention, with and without Roux-en-Y gastric bypass, with one additional year of usual care. Research de...
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Despite numerous reports of relationships between weight-gain and butyrylcholinesterase (BChE), this enzyme's role in the genesis of obesity remains unclear, but recent research points to strong links with ghrelin, the "hunger hormone." The availability of BChE knockout mice (KO) provides an opportunity to clarify the causal relationship between BC...
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Purpose: Although waist circumference can provide important metabolic risk information, logistic issues inhibit its routine use in outpatient practice settings. We assessed whether self-measured waist circumference is sufficiently accurate to replace professionally measured waist circumference for identifying high-risk patients. Methods: Medical...