Publications by authors named "Michelle A Keske"

Skeletal muscle microvascular blood flow (MBF) plays an important role in glucose disposal in muscle. Impairments in muscle MBF contribute to insulin resistance and prediabetes. Animal studies show that short-term (3 day) high-fat feeding blunts skeletal muscle MBF before impairing insulin-stimulated glucose disposal.

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Purpose: Evidence is growing that high salt intake is an independent risk factor for obesity, but the mechanisms are unknown. Our novel working hypothesis is that high salt intake drives cortisol production, which in turn, drives obesity. The current study aimed to demonstrate an acute cortisol response following a single high salt meal.

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The integration of resistance training for cardiac patients leads to important health outcomes that are not optimally obtained with aerobic exercise; these include an increase in muscle mass, maintenance of bone mineral density, and improvements in muscular fitness parameters. Despite the proliferation of evidence supporting resistance exercise in recent decades, the implementation of resistance training is underutilised, and prescription is often sub-optimal in cardiac patients. This is frequently associated with safety concerns and inadequate methods of practical exercise prescription.

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The effect of dietary fat on type 2 diabetes (T2D) risk is unclear. dietary pattern methods have been increasingly used to investigate how dietary fats impact T2D risk. However, the diverse nutrients, foods and dietary patterns reported in these studies requires examination to better understand the role of dietary fats.

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Background: Biomarkers of oxidation-reduction (redox) homeostasis are commonly measured in human blood to assess whether certain stimuli (e.g., high-glucose ingestion or acute exercise) lead to a state of oxidative distress (detrimental to health) or oxidative eustress (beneficial to health).

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Background And Aims: Individual dietary fats can differentially impact on cardiometabolic health. However, their impact within a dietary pattern is not well understood, and warrants comparison with diet quality scores with a dietary fat focus. The aim of this study was to investigate cross-sectional associations between a posteriori dietary patterns characterized by fat type and cardiometabolic health markers, and compare these with two diet quality scores.

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Background: Insufficient physical activity (PA) is a risk factor for the development of many non-communicable diseases. Electric bicycles (e-bikes) offer considerable potential to support people to be physically active, however, no previous e-bike intervention studies have supported e-bike use with behavioural support. The aim of this study was to co-develop theory-based intervention components which can be used to increase physical activity through e-cycling among people who are overweight or obese and physically inactive.

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Background & Aims: Diet and genetic predisposition to adiposity are independent predictors of body composition, yet few cohort studies have examined the association between overall diet quality indices, genetic risk and body composition. This study examined the prospective association of three diet quality indices and a polygenic risk score (PRS) with trunk fat mass, total fat mass, lean mass and bone mineral content.

Methods: Adults from UK Biobank cohort were included.

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Osteoglycin (OGN) and lipocalin-2 (LCN2) are hormones that can be secreted by bone and have been linked to glucose homeostasis in rodents. However, the endocrine role of these hormones in humans is contradictory and unclear. We examined the effects of exercise and meal ingestion on circulating serum OGN and LCN2 levels in eight healthy males {age: 28 [25, 30] years [median ± interquartile range (IQR)] and body mass index [BMI]: 24.

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Adipose tissue microvascular blood flow (MBF) is stimulated postprandially to augment delivery of nutrients and hormones to adipocytes. Adipose tissue MBF is impaired in type 2 diabetes (T2D). Whether healthy individuals at-risk of T2D show similar impairments is unknown.

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There is increasing evidence that skeletal muscle microvascular (capillary) blood flow plays an important role in glucose metabolism by increasing the delivery of glucose and insulin to the myocytes. This process is impaired in insulin-resistant individuals. Studies suggest that in diet-induced insulin-resistant rodents, insulin-mediated skeletal muscle microvascular blood flow is impaired post-short-term high fat feeding, and this occurs before the development of myocyte or whole-body insulin resistance.

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Background Although the impact of dietary fats on cardiovascular disease (CVD) risk is widely researched, longitudinal associations between dietary patterns (DPs) based on fat type and early markers of CVD risk remain unclear. Methods and Results UK Biobank participants (46.9% men, mean age 55 years) with data on early markers of CVD risk (n=12 706) were followed longitudinally (2014-2020; mean 8.

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Article Synopsis
  • - The study investigated the differences in physiological effects between e-cycling (with and without electrical assistance), traditional cycling, and walking, highlighting the potential of e-bikes to promote physical activity.
  • - A systematic review and meta-analysis involving 14 studies revealed that e-cycling with electrical assistance resulted in lower energy expenditure, heart rate, oxygen uptake, power output, and metabolic equivalents compared to conventional cycling.
  • - Despite lower responses in some areas, e-cycling with moderate assistance showed a greater heart rate and oxygen uptake response compared to walking, suggesting health benefits from e-cycling overall.
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Aim: To investigate the effects of mitochondrial-targeted antioxidants (mitoAOXs) on glycaemic control, cardiovascular health, and oxidative stress outcomes in humans.

Materials And Methods: Randomized controlled trials investigating mitoAOX interventions in humans were searched for in databases (MEDLINE-PubMed, Scopus, EMBASE and Cochrane Library) and clinical trial registries up to 10 June 2021. The Cochrane Collaboration's tool for assessing risk of bias and Grading of Recommendations, Assessment, Development and Evaluations were used to assess trial quality and evidence certainty, respectively.

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Insulin infusion increases skeletal muscle microvascular blood flow (MBF) in healthy people but is impaired during insulin resistance. However, we have shown that eliciting insulin secretion via oral glucose loading in healthy people impairs muscle MBF, whilst others have demonstrated intravenous glucose infusion stimulates MBF. We aimed to show that the route of glucose administration (oral versus intravenous) influences muscle MBF, and explore potential gut-derived hormones that may explain these divergent responses.

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Aims/hypothesis: Microvascular blood flow (MBF) increases in skeletal muscle postprandially to aid in glucose delivery and uptake in muscle. This vascular action is impaired in individuals who are obese or have type 2 diabetes. Whether MBF is impaired in normoglycaemic people at risk of type 2 diabetes is unknown.

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Aims: Weight excess and insulin resistance predispose to heart failure. High sodium consumption may contribute to the development of cardiac impairment in insulin-resistant individuals by promoting inadequate skeletal muscle microvascular perfusion response to insulin. We sought to investigate the association of dietary sodium reduction with muscle perfusion, insulin sensitivity, and cardiac function in overweight/obese insulin-resistant (O-IR) normotensive subjects.

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Background: The fat type consumed is considered a risk factor for developing obesity and type 2 diabetes (T2D). However, these associations have not been investigated using a dietary patterns approach, which can capture combinations of foods and fat type consumed.

Objectives: This study aimed to investigate associations between dietary patterns with varying proportions of SFAs, MUFAs, or PUFAs and obesity, abdominal obesity, and self-reported T2D incidence.

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Body composition (fat, skeletal muscle and bone mass) is an important determinant of overall health and risk of endocrine disorders such as type 2 diabetes and osteoporosis. Although diet and physical activity are strongly implicated, body composition is also heritable. We conducted a discovery genome-wide association study on 31 phenotypes from the three-compartment body composition model (fat, lean and bone mass) in a set of 4 386 individuals (n = 2 109 males, n = 2 294 females) from the UK Biobank pilot imaging enhancement program that underwent a dual energy X-ray absorptiometry (DXA) scan for assessment of body composition and genetic screening.

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Reactive oxygen species (ROS) are well known for their role in insulin resistance and the development of cardiometabolic disease including type 2 diabetes mellitus (T2D). Conversely, evidence supports the notion that ROS are a necessary component for glucose cell transport and adaptation to physiological stress including exercise and muscle contraction. Although genetic rodent models and cell culture studies indicate antioxidant treatment to be an effective strategy for targeting ROS to promote health, human findings are largely inconsistent.

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The microvasculature is important for both health and exercise tolerance in a range of populations. However, methodological limitations have meant changes in microvascular blood flow are rarely assessed in humans during interventions designed to affect skeletal muscle blood flow such as the wearing of compression garments. The aim of this study is, for the first time, to use contrast-enhanced ultrasound to directly measure the effects of compression on muscle microvascular blood flow alongside measures of femoral artery blood flow and muscle oxygenation following intense exercise in healthy adults.

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Both obesity and sarcopenia are frequently associated in ageing, and together may promote the progression of related conditions such as diabetes and frailty. However, little is known about the pathophysiological mechanisms underpinning this association. Here we show that systemic alanine metabolism is linked to glycaemic control.

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Background: Evidence suggests that vitamin C supplementation could be a potential therapy in type 2 diabetes. However, its effectiveness and evidence quality require further evaluation.

Purpose: To investigate the efficacy of oral vitamin C supplementation in improving glycemic control, cardiovascular risk factors, and oxidative stress in people with type 2 diabetes.

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Key Points: Exercise, insulin-infusion and low-glucose mixed-nutrient meal ingestion increases muscle microvascular blood flow which in part facilitates glucose delivery and disposal. In contrast, high-glucose ingestion impairs muscle microvascular blood flow which may contribute to impaired postprandial metabolism. We investigated the effects of prior cycling exercise on postprandial muscle microvascular blood flow responses to a high-glucose mixed-nutrient meal ingested 3 and 24 h post-exercise.

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