Hypoxia-induced fatty acid transporter translocation increases fatty acid transport and contributes to lipid accumulation in the heart

AbstractProtein-mediated LCFA transport across plasma membranes is highly regulated by the fatty acid transporters FAT/CD36 and FABPpm. Physiologic stimuli (insulin stimulation, AMP kinase activation) induce the translocation of one or both transporters to the plasma membrane and increase the rate of LCFA transport. In the hypoxic/ischemic heart, intramyocardial lipid accumulation has been attributed to a reduced rate of fatty acid oxidation. However, since acute hypoxia (15min) activates AMPK, we examined whether an increased accumulation of intramyocardial lipid during hypoxia was also attributable to an increased rate of LCFA uptake as a result AMPK-induced translocation of FAT/CD36 and FABPpm. In cardiac myocytes, hypoxia (15min) induced the redistribution of FAT/CD36 from an intracellular pool (LDM) (−25%, P<0.05) to the plasma membranes (PM) (+54%, P<0.05). Hypoxia also induced an increase in FABPpm at the PM (+56%, P<0.05) and a concomitant FABPpm reduction in the LDM (−24%, P<0.05). Similarly, in intact, Langendorff perfused hearts, hypoxia induced the translocation of a both FAT/CD36 and FABPpm to the PM (+66% and +61%, respectively, P<0.05), with a concomitant decline in FAT/CD36 and FABPpm in the LDM (−24% and −23%, respectively, P<0.05). Importantly, the increased plasmalemmal content of these transporters was associated with increases in the initial rates of palmitate uptake into cardiac myocytes (+40%, P<0.05). Acute hypoxia also redirected palmitate into intracellular lipid pools, mainly to PL and TG (+48% and +28%, respectively, P<0.05), while fatty acid oxidation was reduced (−35%, P<0.05). Thus, our data indicate that the increased intracellular lipid accumulation in hypoxic hearts is attributable to both: (a) a reduced rate of fatty acid oxidation and (b) an increased rate of fatty acid transport into the heart, the latter being attributable to a hypoxia-induced translocation of fatty acid transporters

Satiety testing in diabetic gastroparesis: Effects of insulin pump therapy with continuous glucose monitoring on upper gastrointestinal symptoms and gastric myoelectrical activity

BackgroundSymptoms induced by caloric or nonâ caloric satiety test meals and gastric myoelectrical activity (GMA) have not been studied in patients with diabetic gastroparesis (DGP) before and after intense glucose management.AimsWe determined the effects of continuous subcutaneous insulin infusion (CSII) with continuous glucose monitoring (CGM) on GI symptoms, volume consumed, and GMA induced by the caloric meal satiety test (CMST) and water load satiety test (WLST) in DGP.MethodsFortyâ five patients with DGP underwent CMST and WLST at baseline and 24 weeks after CSII with CGM. Subjects ingested the test meals until they were completely full. Visual analog scales were used to quantify preâ and postmeal symptoms, and GMA was recorded with cutaneous electrodes and analyzed visually and by computer.Key ResultsAt baseline and 24â week visits, nausea, bloating, abdominal discomfort, and fullness were immediately increased after CMST and WLST (Ps < 0.01). The meal volumes ingested were significantly less than normal controls at both visits in almost oneâ third of the subjects. After the CMST, the percentage 3 cycle per minute GMA increased and bradygastria decreased compared with WLST (Ps < 0.05). After treatment for 24 weeks meal volumes ingested, postmeal symptoms and GMA were no different than baseline.Conclusions and inferences(a) Satiety test meals elicited symptoms of nausea, bloating, and abdominal discomfort; (b) CMST stimulated more symptoms and changes in GMA than WLST; and (c) CSII with CGM for 24 weeks did not improve symptoms, volumes ingested, or GMA elicited by the two satiety test meals in these patients with diabetic GP. Satiety tests in diabetic gastropresis are useful to study acute postprandial symptoms and GMA, but these measures were not improved by intensive insulin therapy.Water load and caloric load satiety tests immediately increase symptoms associated with gastroparesis. Normal 3 cpm gastric myoelctrical activity increased more after caloric load than water load tests. After 24 weeks of insulin therapy there were no differences in volumes ingested, symptoms or gastric myooelectrical activity.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152474/1/nmo13720_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152474/2/nmo13720.pd

The effects of baseline characteristics, glycaemia treatment approach, and glycated haemoglobin concentration on the risk of severe hypoglycaemia: post hoc epidemiological analysis of the ACCORD study

Objectives To investigate potential determinants of severe hypoglycaemia, including baseline characteristics, in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial and the association of severe hypoglycaemia with levels of glycated haemoglobin (haemoglobin A1C) achieved during therapy

Mapping adipose and muscle tissue expression quantitative trait loci in African Americans to identify genes for type 2 diabetes and obesity

Relative to European Americans, type 2 diabetes (T2D) is more prevalent in African Americans (AAs). Genetic variation may modulate transcript abundance in insulin-responsive tissues and contribute to risk; yet published studies identifying expression quantitative trait loci (eQTLs) in African ancestry populations are restricted to blood cells. This study aims to develop a map of genetically regulated transcripts expressed in tissues important for glucose homeostasis in AAs, critical for identifying the genetic etiology of T2D and related traits. Quantitative measures of adipose and muscle gene expression, and genotypic data were integrated in 260 non-diabetic AAs to identify expression regulatory variants. Their roles in genetic susceptibility to T2D, and related metabolic phenotypes were evaluated by mining GWAS datasets. eQTL analysis identified 1,971 and 2,078 cis-eGenes in adipose and muscle, respectively. Cis-eQTLs for 885 transcripts including top cis-eGenes CHURC1, USMG5, and ERAP2, were identified in both tissues. 62.1% of top cis-eSNPs were within ±50kb of transcription start sites and cis-eGenes were enriched for mitochondrial transcripts. Mining GWAS databases revealed association of cis-eSNPs for more than 50 genes with T2D (e.g. PIK3C2A, RBMS1, UFSP1), gluco-metabolic phenotypes, (e.g. INPP5E, SNX17, ERAP2, FN3KRP), and obesity (e.g. POMC, CPEB4). Integration of GWAS meta-analysis data from AA cohorts revealed the most significant association for cis-eSNPs of ATP5SL and MCCC1 genes, with T2D and BMI, respectively. This study developed the first comprehensive map of adipose and muscle tissue eQTLs in AAs (publically accessible at https://mdsetaa.phs.wakehealth.edu) and identified genetically-regulated transcripts for delineating genetic causes of T2D, and related metabolic phenotypes

Inpatient Hyperglycemia: Slide through the Scale But Cover the Bases First

KEYWORDS: diabetes, inpatient hyperglycemia, hypoglycemia, insulin sliding scale. A very compelling and growing body of evidence highlights the benefits to hospitalized patients of intensive (insulin-based) glycemic control. However, we have a tendency to attend to patients&apos; &quot;acute&quot; problems during inpatient stays, and glycemic control frequently takes a backseat. As hospitalists, we frequently come across patients with diabetes admitted for various other reasons, as well as patients who develop hyperglycemia while hospitalized. During a hospital stay, it is usually not recommended that an oral hypoglycemic regimen be continued, and insulin use is necessary to more reliably control blood glucose. In this article, we emphasize the need to better manage inpatient hyperglycemia and to make a conscious effort to prescribe insulin in a more rational manner. We propose that insulin orders for an inpatient address: (1) basal insulinization, (2) meal or prandial insulin, and (3) corrective insulin. In this schema, the supplemental boluses of insulin administered to correct a blood glucose level that exceeds a set value are viewed as an adjunct to a basal/bolus insulin regimen. We also recognize the practical limitations of attaining stringent glucose targets and pinpoint those areas in need of further research