Absence Of Hyperglycemia Research Articles

Inverse Association between Iron Deficiency and Glycated Hemoglobin Levels in Ghanaian Adults—the RODAM Study

ABSTRACTBackgroundGlycated hemoglobin (HbA1c) is often used to diagnose type 2 diabetes (T2D), but studies show that iron deficiency (ID) is associated with elevated HbA1c in the absence of hyperglycemia. It is unknown whether ID prevalence varies between sub-Saharan African populations living in different locations and whether ID influences HbA1c levels in these populations.ObjectivesWe assessed the prevalence of ID among Ghanaian migrants in Europe and nonmigrant Ghanaians, and the influence of ID on HbA1c categories among Ghanaians without T2D.MethodsWe used the database from the cross-sectional RODAM (Research on Obesity and Diabetes among African Migrants) study. This contained data on 3377 Ghanaian men and women aged 25–70 y living in urban and rural Ghana and Ghanaian migrants living in Amsterdam, London, and Berlin. ID was defined as ferritin < 15 ng/mL or, if C-reactive protein was ≥5 mg/mL, as ferritin < 30 ng/mL according to the WHO. We used binary logistic regression to assess differences in ID between sites and its association with clinically defined HbA1c categories (<5.5%, ≥5.5% to <6.5%, ≥6.5%). Men and women were analyzed separately.ResultsThe prevalence of ID was higher in migrant [28.4%; adjusted OR (aOR): 3.08; 95% CI: 2.04, 4.65)] and urban (23.2%; aOR: 2.37; 95% CI: 1.56, 3.59) women than in rural women (11.9%). Among women, ID was associated with higher odds of HbA1c ≥ 5.5% to <6.5% in the absence of hyperglycemia (aOR: 1.43; 95% CI: 1.08, 1.87). This association was not found in men.ConclusionsFurther research is needed to identify factors underlying the high prevalence of ID among urban and migrant Ghanaian women, and the association of ID with HbA1c ≥ 5.5% to <6.5% in women. In addition, our study reinforces the need to consider iron concentrations if interpreting HbA1c among African populations.

Is The Hexosamine Biosynthesis Pathway Affected By Inflammation In Endothelial Cells?

Excessive addition of β-linked N-acetylglucosamine (O-GlcNAc) via the hexosamine biosynthesis pathway (HBP) occurs with diabetes and decreases in muscles with exercise. HBP flux increases inflammation and may be specifically important in the activation phase of the inflammatory response. Inflammation plays a key role in insulin resistance and hyperglycemia (HG), with the process contributing to the development of diabetes and associated complications. β-cell development and differentiation are affected by the HBP, and O-GlcNAc has been indicated in insulin secretion from the pancreas (1). PURPOSE: We explored whether in the absence of HG, an inflammatory insult, can affect key factors in this pathway and total O-GlcNAcylation within the endothelium. Because African Americans are overrepresented in conditions involving chronic inflammation, potential racial differences were also examined. METHODS: Human umbilical vein endothelial cells (HUVECs), n=6, were stimulated with 10ng/mL of tumor necrosis factor alpha (TNFα) for 4 hours, or treated as a control. Western blot procedures were used to measure expression of the HBP rate-limiting enzyme (GFAT) and the transferase that adds the end-product onto proteins (OGT). Total protein O-GlcNAcylation (O-GlcNAc) was also measured. RESULTS: With TNFα stimulation, there was no difference in GFAT (0.63 + .09 vs 0.62 + .08, p=.89), OGT (0.49 + .09 vs 0.41 + .08, p=.56), nor total O-GlcNAc (1.56 + .38 vs 1.77 + .42, p=.71) expression compared to controls. There were no racial differences found among the various conditions (p>.05) with either of the proteins examined. CONCLUSIONS: The HBP is not altered with acute inflammation in endothelial cells (ECs), with no racial differences additionally found. Low-grade inflammation vitally contributes to diabetes, atherosclerosis, and their complications, with the HBP playing a role in each. We conclude that HG may be necessary to work in conjunction with inflammation to increase protein O-GlcNAcylation in ECs. Although increased flux though the HBP has been shown to upregulate inflammation, the reverse relationship cannot be confirmed. Future research is needed to examine links between this pathway, various conditions, and the ability of exercise to alter it within the endothelium.

MON-677 A Neuro-Radiological Stroke Mimicker: Non-Ketotic Hyperglycemia Induced Occipital Lobe Hyperdensity Presenting with Seizures

Background: Acute hyperglycemia in absence of DKA or HHS is a common cause for hospitalization and is termed as Non-Ketotic Hyperglycemia (NKH). NKH-related occipital lobe seizure activity is a rare entity and it’s neuroradiological findings can be confused for acute stroke. We describe a case of NKH-related seizure activity presenting with distinct MRI findings. Clinical Case: 19-year-old male with DM-1 presented with complaints of burning and numbness involving the left side of face, left upper and lower extremity. These lasted for a few hours and had resolved upon arrival to the ER. At the time of presentation, vitals were stable. Physical examination was significant for flat affect with delayed response to questions without any focal deficits. History obtained from his father revealed that he has had similar episodes of decreased responsiveness during periods of acute hyperglycemia. Laboratory values were significant for glucose of 779mg/dl and sodium of 126mMol/L. Absence of ketones or acidosis ruled out DKA. Normal serum osmolality of 295 ruled out HHS. HbA1c >15% confirmed his non-compliance to insulin use. UDS was negative. Patient was admitted and started on insulin basal/bolus regimen. On the second day of hospitalisation, rapid response was called for seizure-like activity characterised by twitching of left side of face, staring into space and deviation of eyes to left upper corner. This resolved with IV lorazepam without any residual focal deficits. Glucose at the time of seizure was 425mg/dl. He was started on levetiracetam and EEG thereafter revealed no seizure-like activity. CT head and CT angiogram of the head and neck were negative. However MRI showed T2 hyperintensity and restricted diffusion with edema throughout the right occipital lobe. Neurology suspected stroke. However, extensive stroke workup for infectious, autoimmune and hypercoagulable states remained negative. Glucose control was achieved and patient was subsequently discharged on a strict insulin regimen and outpatient follow up with an endocrinologist. Conclusion: NKH is known to manifest as seizure activity and thus, should be considered an endocrine emergency requiring prompt diabetic management. The suggested pathophysiology for seizures is prolonged hyperglycemia leading to oxidative stress and cellular edema. Furthermore, this may contribute to the unique MRI findings and should not be confused for an acute stroke.

Clinical Outcome of Patients With Large Vessel Occlusion and Low National Institutes of Health Stroke Scale Scores: Subanalysis of the RESCUE-Japan Registry 2.

Background and Purpose- The treatment and prognosis of acute large vessel occlusion with mild symptoms have not been sufficiently studied. The present study aimed to investigate the clinical or radiological predictors of clinical outcome in patients with stroke with mild symptoms due to acute large vessel occlusion. Methods- Of 2420 patients with acute large vessel occlusion in the RESCUE-Japan Registry 2 (Recovery by Endovascular Salvage for Cerebral Ultra-Acute Embolism-Japan Registry 2), a multicenter prospective registry in Japan, patients with modified Rankin Scale scores of 0 to 2 before onset and initial National Institutes of Health Stroke Scale (NIHSS) scores of 0 to 5 were examined in post hoc analysis. We examined the clinical and radiological characteristics associated with a favorable outcome (modified Rankin Scale score, 0-2 at 90 days) using multivariate analysis, as well as the factors associated with a favorable outcome in patients treated with endovascular therapy. Results- We analyzed 272 patients (median age, 73 years; median NIHSS score on admission, 3). Eighty-six (31.6%) patients were treated with intravenous recombinant tissue-type plasminogen activator, 54 (19.9%) underwent endovascular therapy, and 208 (76.5%) showed a favorable outcome. In multivariate analysis, age <75 years (odds ratio [OR], 2.42 [95% CI, 1.30-4.50]), initial NIHSS score 0 to 3 (OR, 3.08 [95% CI, 1.59-5.98]), intravenous recombinant tissue-type plasminogen activator (OR, 2. 86 [95% CI, 1.32-6.21]), and blood glucose level ≤140 mg/dL (OR, 2.37 [95% CI, 1.22-4.60]) were independently associated with a favorable outcome. However, endovascular therapy was not associated with a favorable outcome (OR, 1.65 [95% CI, 0.71-3.88]). Among 54 patients treated with endovascular therapy, good reperfusion status was more common in the favorable outcome group (88.6% versus 60.0%; P<0.05). Conclusions- Younger age, lower initial NIHSS score, intravenous recombinant tissue-type plasminogen activator, and absence of hyperglycemia were independently associated with a favorable outcome in patients with acute large vessel occlusion with low NIHSS scores. Registration- URL: https://www.clinicaltrials.gov; Unique identifier: NCT02419794.

Dicarbonyl-mediated AGEing and diabetic kidney disease.

Increased glycolytic flux into the diabetic kidney, combined with glycolytic inefficiencies introduced by oxidative stress, acts to increase the generation of triose-phosphate intermediates, which spontaneously degrade to form methylglyoxal. At the same time, the glyoxalase-catalysed pathway that degrades excess methylglyoxal is impaired. The resulting dicarbonyl stress increases the accumulation of Advanced Glycation End-products (AGEs), as highly reactive dicarbonyls modify proteins, DNA, phospholipids and even small molecules like glutathione and nitric oxide. The resulting molecular dysfunction, contributes to the development and progression of kidney disease in diabetes. The importance of the dicarbonyls in diabetic kidney disease is clearly demonstrated by the reno-protective benefits of structurally-disparate dicarbonyl scavengers in experimental studies. Equally, modulating the glyoxalase pathway is able to alter both dicarbonyl generation and renal dysfunction in the presence and absence of hyperglycaemia. However, beyond improving glycemia control and reducing oxidative stress, an effective way to attenuate dicarbonyl-mediated damage in patients with diabetic kidney disease remains an elusive goal.

Improvement in Hyperglycemia Prevents Surgical Site Infection Irrespective of Insulin Therapy in Non-diabetic Patients Undergoing Gastrointestinal Surgery

BackgroundIntensive glycemic control is recommended to prevent surgical site infections (SSI). Our aim was to evaluate retrospectively the effect of improvement in hyperglycemia irrespective of insulin use on the incidence of SSI in non-diabetic patients.MethodsThe highest blood glucose (BG) concentration within 12 h (early peak BG) and the final BG from 12 to 24 h after surgery were evaluated in patients who underwent gastrointestinal surgery. Patients with an early peak BG of ≥150 mg/dL were divided into those with persistent (final BG of ≥150 mg/dL) and improved hyperglycemia (final BG of <150 mg/dL). Patients without hyperglycemia and those with late-onset hyperglycemia were also assessed for SSI risk.ResultsOverall, 1612 patients were studied (diabetes, n = 293). Although hyperglycemia increased the SSI rates in non-diabetic patients, no correlation was demonstrated in patients with diabetes at any cutoff final BG defining htperglycemia except for 180 mg/dL. Hyperglycemia improved without insulin therapy in 283 of 512 non-diabetic patients who had early hyperglycemia. The adjusted standardized residual for those with SSI and persistent hyperglycemia was 5.2 (P < 0.05). In contrast, the absence of hyperglycemia was a significant preventive factor for SSI. In the multivariate analyses, persistent hyperglycemia was an independent risk factor for SSI (odds ratio 1.54; 95% confidence interval 1.03–2.31).ConclusionsRemission of hyperglycemia within 24 h after surgery prevented SSI in non-diabetic patients. Considering that hyperglycemia improved in approximately half of patients without insulin therapy, commencement of insulin dosing after two consecutive BGs of ≥150 mg/dL might be reasonable, especially in general wards.

Pathophysiological model of indirect revascularization in rats with microangiopathy of limbs caused by experimental streptozocin diabetes

Despite the large number of publications, the model of experimental diabetes after the introduction of streptozotocin remains a subject of lively scientific debate. The purpose of this study was to develop a pathophysiological model of indirect revascularization in rats with microangiopathy of limbs caused by experimental streptozotocin diabetes. Experimental studies were carried out in a chronic experiment on 100 sexually mature Wistar rats weighing 180-250 g. The streptozotocin diabetes model used. After culling animals from increased resistance to pancreatotropic toxicity by the criterion of the absence of hyperglycemia, three experimental groups were formed: Group I (control) – rats with streptozotocin-induced angiopathy without treatment (n=10); II group – rats with streptozotocin-induced angiopathy treated with pentoxifylline (100 mg/kg IP for 10 days) for therapeutic purposes (n=25); III group – rats with streptozotocin-induced angiopathy, which together with the treatment were injected with platelet-rich plasma (in the right hind limb, once, with a volume of 0.2 ml, linearly, retrogradely, from two points) and pentoxifylline (100 mg/kg IP for 10 days) (n=25). The duration of the experiment was 110 days. We studied the level of glycemia, the state of microcirculation, and the degree of pathomorphological changes in the various study groups. Statistical processing was performed by non-parametric methods using software Statistica 10.0. The developed pathophysiological model of indirect revascularization with the introduction of pentoxifylline and plasma enriched with platelets in diabetic angiopathy is adequate to the needs of clinical physiology. It has been shown that the isolated administration of pentoxifylline is inferior to combined therapy by revascularizing activity. The results of the work may be an experimental justification for the feasibility of clinical application of the combination of pentoxifylline and platelets rich plasma in the treatment of diabetic angiopathy, as well as its use in prophylactic purposes in patients with diabetes mellitus.

MON-127 Euglycemic Diabetic Ketoacidosis: A Rare Complication of a Common Disease

INTRODUCTION Euglycemic diabetic ketoacidosis (EDKA) is a clinical triad comprising of blood glucose (BG) levels<200mg/dL, increased anion gap (AG) metabolic acidosis and ketonemia or ketonuria. It remains one of the most serious complications of diabetes as in the absence of hyperglycemia, DKA may be overlooked leading to a delay in appropriate diagnosis and management. CLINICAL CASE A 43-year old male with history of uncontrolled type 1 DM of 20 years, complicated by peripheral neuropathy, diabetic retinopathy, ESRD on hemodialysis, CVA, and hypertension presented with abdominal pain and bloody stools for three days. On admission, he was hemodynamically stable. On examination, he had dry mucous membranes and diffuse abdominal tenderness. Lab work revealed leukocytosis, electrolyte derangements, normal AG and BG of 94mg/dL. Liver chemistry and lipase were normal. CT scan of the abdomen showed a wedge shaped infarct in the anterolateral spleen. Fluid resuscitation with normal saline was started. To maintain glycemic control in the hospital, low dose basal insulin was administered. However, patient developed significant symptomatic hypoglycemia overnight with BG as low as 26mg/dL. 5% dextrose in half normal saline and dextrose were administered which improved BG to 134mmol/L. Labs and blood gas drawn the next morning revealed an AG metabolic acidosis (pH:7.26, HCO3:18mmol/L) with gap of 25mmol/L. Betahydroxybutyrate was elevated (2.5mmol/L). He was diagnosed with EDKA and started on intravenous insulin drip per protocol. A basic metabolic panel was checked every 4 hours with glucose monitored every hour. Subsequently his anion gap closed and acidosis resolved. He was carefully transitioned to basal and bolus insulin regimen. DISCUSSION The mechanism of EDKA is not well known but is thought to be commonly due to decreased gluconeogenesis in liver during fasting state or enhanced urinary excretion of glucose induced by an excess of counter regulatory hormones. EDKA has been associated with low caloric intake, fasting, dehydration, pregnancy, pancreatitis, cocaine intoxication, prolonged vomiting, diarrhea, SGLT2 inhibitor and insulin pump use (1). In our patient, EDKA most likely occurred due to dehydration and low caloric intake in setting of his abdominal pain due to splenic infarct. The principle of treatment of EDKA is to restore fluid and electrolyte losses along with insulin administration to resolve the anion gap. CONCLUSION Euglycemic DKA poses a diagnostic challenge and remains a rare complication of a common disease. A high clinical suspicion is warranted to diagnose and treat it appropriately as a medical emergency. REFERENCES 1. Peters AL, Buschur EO, Buse JB, Cohan P, Diner JC, Hirsch IB. Euglycemic Diabetic Ketoacidosis: A Potential Complication of Treatment With Sodium-Glucose Cotransporter 2 Inhibition. Diabetes Care. 2015;38(9):1687-1693. doi:10.2337/dc15-0843

Glucose-dependent Insulinotropic Polypeptide (GIP) Resistance and \u03b2-cell Dysfunction Contribute to Hyperglycaemia in Acromegaly

Impaired insulin sensitivity (IS) and β-cell dysfunction result in hyperglycaemia in patients of acromegaly. However, alterations in incretins and their impact on glucose-insulin homeostasis in these patients still remain elusive. Twenty patients of active acromegaly (10 each, with and without diabetes) underwent hyperinsulinemic euglycaemic clamp and mixed meal test, before and after surgery, to measure indices of IS, β-cell function, GIP, GLP-1 and glucagon response. Immunohistochemistry (IHC) for GIP and GLP-1 was also done on intestinal biopsies of all acromegalics and healthy controls. Patients of acromegaly, irrespective of presence or absence of hyperglycaemia, had similar degree of insulin resistance, however patients with diabetes exhibited hyperglucagonemia, and compromised β-cell function despite significantly higher GIP levels. After surgery, indices of IS improved, GIP and glucagon levels decreased significantly in both the groups, while there was no significant change in indices of β-cell function in those with hyperglycaemia. IHC positivity for GIP, but not GLP-1, staining cells in duodenum and colon was significantly lower in acromegalics with diabetes as compared to healthy controls possibly because of high K-cell turnover. Chronic GH excess induces an equipoise insulin resistance in patients of acromegaly irrespective of their glycaemic status. Dysglycaemia in these patients is an outcome of β-cell dysfunction consequent to GIP resistance and hyperglucagonemia.

Mild Hypercaloric Intake is Associated with an Impaired Vascular Smooth Muscle Phenotype in Absence of Hyperglycemia: Potential Modulation by Anti‐diabetic Drugs

Cardiovascular disease is the leading cause of mortality and morbidity in diabetes. Diabetes‐induced vascular complications are associated with the contractile‐to‐synthetic phenotypic switch of the vascular smooth muscle cells (VSMCs). Emerging experimental and clinical data have shown that functionally impaired VSMCs contribute to the high incidence rates of macrovascular complications in diabetes. Moreover, a significant proportion of diabetic patients show signs of vascular impairment at initial presentation before prolonged exposure to hyperglycemia. The underlying mechanisms leading to VSMC deterioration, particularly in early stages of metabolic dysfunction, remain largely unknown. In this study, we have investigated VSMC phenotypic alterations in a model of early metabolic derangements. Rats fed a mild hypercaloric (MHC) diet were used at time points prior to the development of hyperglycemia. Aortic VSMCs were isolated from control rats, from MHC fed rats sacrificed after 4, 8, or 12 weeks of exposure. At twelve weeks, MHC‐fed rats did not show increased fasting or random blood glucose, impaired glucose tolerance, increased weight, or hypertension. The effect of a two‐week treatment with metformin and pioglitazone prior to sacrifice at the 12‐week time point was examined. A gradual reduction in VSMC activity in MTS assays was observed as a function of MHC‐feeding duration, with the sharpest decrease observed at 12 weeks. Cell cycle assays revealed no changes in cell proliferation indicating that the changes in MTS assays were rather a reduction in metabolic activity. Moreover, expression of VSMC contractile phenotype markers, a‐smooth muscle actin and calponin, decreased progressively with MHC feeding. Interestingly, in vivo treatment with non‐hypoglycemic doses of either metformin and pioglitazone, known to have positive vascular pleiotropic effects, restored VSMCs metabolic activity and contractile marker expression to control levels. Significantly, no changes were detected VSMC metabolic activity and contractile marker expression following in vitro exposure to either a range of concentrations of free fatty acids, to simulate the MHC diet effect, or to metformin or pioglitazone. The contrast between in vitro and in vivo results suggests a direct effect of lipids on VSMC phenotype and function is unlikely; however, the changes observed might be a result of a more complex interaction with more than one tissue type. We hypothesize that the observed effect of MHC diet is mediated by the induction of perivascular adipose inflammation. Studies are underway to verify this claim.Support or Funding InformationSupported by AUB MPP fund #320148This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Methylglyoxal induces retinopathy-type lesions in the absence of hyperglycemia: studies in a rat model.

The aim of this study was to evaluate whether damage to the neurovascular unit in diabetes depends on reactive metabolites such as methylglyoxal (MG), and to assess its impact on retinal gene expression. Male Wistar rats were supplied with MG (50 mM) by drinking water and compared with age-matched streptozotocin-diabetic animals and untreated controls. Retinal damage was evaluated for the accumulation of MG-derived advanced glycation end products, changes in hexosamine and PKC pathway activation, microglial activation, vascular alterations (pericyte loss and vasoregression), neuroretinal function assessed by electroretinogram, and neurodegeneration. Retinal gene regulation was studied by microarray analysis, and transcription factor involvement was identified by upstream regulator analysis. Systemic application of MG by drinking water increased retinal MG to levels comparable with diabetic animals. Elevated retinal MG resulted in MG-derived hydroimidazolone modifications in the ganglion cell layer, inner nuclear layer, and outer nuclear layer, a moderate activation of the hexosamine pathway, a pan-retinal activation of microglia, loss of pericytes, increased formation of acellular capillaries, decreased function of bipolar cells, and increased expression of the crystallin gene family. MG mimics important aspects of diabetic retinopathy and plays a pathogenic role in microglial activation, vascular damage, and neuroretinal dysfunction. In response to MG, the retina induces expression of neuroprotective crystallins.-Schlotterer, A., Kolibabka, M., Lin, J., Acunman, K., Dietrich, N., Sticht, C., Fleming, T., Nawroth, P., Hammes, H.-P. Methylglyoxal induces retinopathy-type lesions in the absence of hyperglycemia: studies in a rat model.

Progressive Improvement in Endothelial Nitric Oxide Release due to Synthase Dimer Formation with LDL Reductions below 70 mg/dL during Hyperglycemia

In diabetes, endothelial cell (EC) dysfunction is characterized by reduced nitric oxide (NO) release and increased nitroxidative stress due to NO synthase (eNOS) dimer uncoupling. Reductions in LDL improve EC function but the effect is not well understood at levels below the target of 70 mg/dL. We measured NO and peroxynitrite (ONOO−) release as well as eNOS dimer formation in ECs under hyperglycemic conditions following progressive reductions of LDL in vitro. Human umbilical vein endothelial cells (HUVECs) were incubated with LDL at concentrations ranging from 150 to &amp;lt;10 mg/dL with high glucose (250 mg/dL). Cells were stimulated with calcium ionophore, and assayed for NO and ONOO− release using porphyrinic sensors. eNOS dimer levels were measured using immunochemical approaches. Results showed that reductions in LDL levels had a disproportionate benefit on endothelial NO and ONOO− release below 70 mg/dL. A reduction in LDL levels from 70 to &amp;lt;10 mg/dL produced a 181% increase in NO release (163 ± 18 to 458 ± 34 nM; p&amp;lt;0.0001) and 116% decrease in ONOO− release (393 ± 27 to 182 ± 23 nM; p&amp;lt;0.0001), corresponding to a 513% increase in the NO-to-ONOO− release ratio (0.42 ± 0.04 to 2.56 ± 0.40; p&amp;lt;0.0001), a comprehensive indicator of EC function. These changes also correlated with increased eNOS dimer formation by 819%. By contrast, only a modest 27% change in EC function was observed as LDL levels were reduced from 150 to 70 mg/dL with regard to the NO-to-ONOO− release ratio. In the absence of hyperglycemia, the benefits of LDL lowering on EC function and eNOS dimerization were also very evident, but to a lesser extent. Thus, progressive improvements in endothelial NO bioavailability and eNOS dimer formation were observed at LDL levels below 70 mg/dL to &amp;lt;10 mg/dL. These in vitro data suggest that reductions in LDL to very low levels may be effective in reversing EC dysfunction for the diabetic patient. Disclosure R. Mason: Research Support; Self; Amarin Corporation, Amgen Inc., Pfizer Inc.. Consultant; Self; Amarin Corporation. Speaker's Bureau; Self; Pfizer Inc.. H.E. Dawoud: None. S. Sherratt: None. T. Malinski: None.

Tubular NHE3 is a determinant of the acute natriuretic and chronic blood pressure lowering effect of the SGLT2 inhibitor empagliflozin

The sodium glucose cotransporter 2 (SGLT2) inhibitor, empagliflozin, is a new antihyperglycemic drug that also lowers blood pressure and has beneficial effects in patients with heart failure (EMPA‐REG OUTCOME). These effects may relate at least in part to its natriuretic effect. In the brush border of the early proximal tubule, SGLT2 may interact with the Na+‐H+‐exchanger NHE3, which reabsorbs about 30% of Na+ in the proximal convoluted tubule. Here we determine whether the acute or chronic natriuretic effect of empagliflozin depends on intact tubular NHE3.MethodsWe generated mice with NHE3 knock‐down in the tubular system (NHE3‐KO; using Pax8‐Cre) and compared them with littermate controls (WT). In a first series, we determined acute effects of empagliflozin (0.3 mg/kg, given by oral gavage together with a water load to facilitate quantitative urine collection over 3 hours) or vehicle on urinary pH and excretion of fluid, Na, and bicarbonate in metabolic cage studies (n=9–11/group). In a second series, we treated mice for 4 months with empagliflozin (150 mg/kg of diet) or vehicle and measured systolic blood pressure (SBP) by automated tail cuff in trained awake mice and renal renin mRNA expression by RT‐qPCR (n=10/group for renin mRNA and 15–26/group for SBP).ResultsSeries 1In WT, empagliflozin significantly enhanced urinary pH and the excretion of glucose, fluid, Na and bicarbonate compared with vehicle control. In NHE3‐KO, urine pH and bicarbonate excretion were significantly greater than in WT in response to vehicle; however, these two parameters were not significantly changed in response to empagliflozin. Moreover, empagliflozin actually reduced urine Na excretion in NHE3‐KO.Series 2In WT, empagliflozin lowered SBP and enhanced renal renin mRNA expression, consistent with a sustained natriuretic effect. In vehicle‐treated NHE3‐KO, SBP was lower and renal renin mRNA higher compared with WT; however, these two parameters were not significantly changed in response to empagliflozin.ConclusionThe data are consistent with the notion that the acute natriuretic and the chronic blood pressure lowering effect of the SGLT2 inhibitor empagliflozin involve a functional interaction with tubular NHE3, and can occur in the absence of hyperglycemia. The chosen dose of empagliflozin only induced a mild glucosuria, i.e. glucose reabsorption through downstream SGLT1 had just been fully saturated. Since SGLT1 transports Na and glucose in a ratio of 2:1 versus 1:1 for SGLT2, shifting glucose reabsorption from SGLT2 to downstream SGLT1 can explain an anti‐natriuretic effect of empagliflozin that has been unmasked by the absence of tubular NHE3.Support or Funding InformationNIH R01DK112042, R01DK106102, P30DK079337, the Department of Veterans Affairs, Boehringer Ingelheim Pharma GmbH &amp; Co.KGThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Endothelial Dysfunction as a result of Hypercaloric Intake: Underlying Mechanism in Absence of Hyperglycemia

Endothelial dysfunction is a common occurrence in diabetes, secondary to hyperglycemia. However, little is known about the mechanism underlying the early endothelial damage occurring in the course of diabetes development prior to impaired glycemic control. We used a high‐calorie (HC) diet rat model with delayed development of hyperglycemia to address this question. Aortic rings from HC rats exhibited impaired endothelium‐dependent relaxation of phenylephrine (PE)‐induced tone to acetylcholine (ACh), where higher concentrations of ACh caused an increase in contractile tone. On the other hand, similar relaxation patterns to the exogenous nitric oxide (NO) donor, sodium nitroprusside, were observed indicating that the defect is endothelial in origin. Hence, the possible role of an endothelium‐derived contractile agent, such as endothelin‐1 and 20‐HETE, or an increased production of reactive oxygen species due to uncoupling of endothelial NO synthase, as the basis of increased tone caused by higher ACh concentrations was ruled out. In aortic rings from control rats, endothelium‐dependent relaxation to ACh was comprised of a major NO component with a lesser contribution from inward rectifier potassium channel (Kir)‐dependent mechanisms, particularly at higher ACh concentrations. While both components of the response were affected, HC‐feeding appears to abolish the Kir‐dependent pathway completely. Protein levels of Kir 2.1 subunit were down‐regulated in aortic tissues from HC‐fed rats. Using U‐46619, a thromboxane analogue, to evoke contraction involving calcium sensitization, rather than depolarization, aortic rings from control rats demonstrated a NO‐dependent, hyperpolarization‐independent pattern of relaxation in response to ACh. Despite a slightly more blunted response to ACh, HC rings pre‐contracted with U‐46619 did not show the terminal contraction observed in tissues contracted with PE. These results potentially implicate impaired myoendothelial coupling as the underlying mechanism for endothelial dysfunction in diabetes. Further examination of the role and expression of gap junctions in these tissues in under way.Support or Funding InformationSupported by AUB MPP fund #320148This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Phenotypic alteration of vascular smooth muscle cells as a sequence of mild hyper‐caloric intake in the absence of hyperglycemia: Potential modulation by antidiabetic drugs

Diabetic patients remain at a high risk of atherosclerotic cardiovascular disease in addition to hypertension and microvascular complications. A significant proportion of diabetic patients present with vascular abnormalities upon initial diagnosis implicating an early vascular insult in the course of development of diabetes. A contractile‐to‐synthetic vascular smooth muscle cell (VSMC) phenotypic switch is associated with different diseases including atherosclerosis, diabetes, hypertension, and cancer. In the present study, we examined whether early metabolic derangement in the course of diabetes development was associated with VSMC phenotypic alteration before hyperglycemia develops. For this purpose, we used a high‐calorie diet (HC) fed rat model with delayed development of hyperglycemia. Up to 12 weeks of feeding, neither increased serum glucose nor elevated mean arterial pressure was detected. Control and HC rats were sacrificed at 4, 8, and 12 weeks, and their aortae were dissected for isolation of primary VSMCs. VSMC morphology changed whereby the typical hill‐and‐valley culture pattern was gradually substituted by densely packed areas of rhomboid cells in explants for aortic tissues from HC rats. This changed appeared to be dependent on the duration of feeding. VSMC proliferation and migration increased in cultures derived from HC‐fed rats compared to controls at the same age and passage number. Moreover, VSMC contractile phenotype markers smooth muscle alpha actin and calponin gradually decreased in cells cultured from HC‐fed rats in a manner proportional to the feeding duration. In vitro, exposure to pioglitazone, but not metformin was associated with a reduction in VSMC proliferation in cells derived from HC‐fed rats. On the contrary, similar exposure to increased oleiate and palmitate concentrations in the culture medium resulted in an increased proliferation of VSMCs from control rats. Our results indicate that VSMC phenotype and function is potentially affected by the early metabolic derangement associated with the development of diabetes regardless of the blood glucose concentration. Studies to investigate the effect of chronic exposure of HC‐fed rats to metformin and pioglitazone on VSMC phenotype are underway.Support or Funding InformationSupported by AUB MPP fund #320148This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Advanced glycation end products induce neural tube defects through elevating oxidative stress in mice.

Our previous study showed an association between advanced glycation end products (AGEs) and neural tube defects (NTDs). To understand the molecular mechanisms underlying the effect of AGEs on neural tube development, C57BL/6 female mice were fed for 4 weeks with commercial food containing 3% advanced glycation end product bovine serum albumin (AGE-BSA) or 3% bovine serum albumin (BSA) as a control. After mating mice, oxidative stress markers including malondialdehyde and H2O2 were measured at embryonic day 7.5 (E7.5) of gestation, and the level of intracellular reactive oxygen species (ROS) in embryonic cells was determined at E8.5. In addition to evaluating NTDs, an enzyme-linked immunosorbent assay was used to determine the effect of embryonic protein administration on the N-(carboxymethyl) lysine reactivity of acid and carboxyethyl lysine antibodies at E10.5. The results showed a remarkable increase in the incidence of NTDs at E10.5 in embryos of mice fed with AGE-BSA (no hyperglycemia) compared with control mice. Moreover, embryonic protein administration resulted in a noticeable increase in the reactivity of N-(carboxymethyl) lysine and N(ε)-(carboxyethyl) lysine antibodies. Malondialdehyde and H2O2 levels in embryonic cells were increased at E7.5, followed by increased intracellular ROS levels at E8.5. Vitamin E supplementation could partially recover these phenomena. Collectively, these results suggest that AGE-BSA could induce NTDs in the absence of hyperglycemia by an underlying mechanism that is at least partially associated with its capacity to increase embryonic oxidative stress levels.

Diabetes Is Not Associated With Increased 90-Day Mortality Risk in Critically Ill Patients With Sepsis.

To determine the association of pre-existing diabetes, hyperglycemia, and hypoglycemia during the first 24 hours of ICU admissions with 90-day mortality in patients with sepsis admitted to the ICU. We used mixed effects logistic regression to analyze the association of diabetes, hyperglycemia, and hypoglycemia with 90-day mortality (n = 128,222). All ICUs in the Netherlands between January 2009 and 2014 that participated in the Dutch National Intensive Care Evaluation registry. All unplanned ICU admissions in patients with sepsis. The association between 90-day mortality and pre-existing diabetes, hyperglycemia, and hypoglycemia, corrected for other factors, was analyzed using a generalized linear mixed effect model. In a multivariable analysis, diabetes was not associated with increased 90-day mortality. In diabetes patients, only severe hypoglycemia in the absence of hyperglycemia was associated with increased 90-day mortality (odds ratio, 2.95; 95% CI, 1.19-7.32), whereas in patients without pre-existing diabetes, several combinations of abnormal glucose levels were associated with increased 90-day mortality. In the current retrospective large database review, diabetes was not associated with adjusted 90-day mortality risk in critically ill patients admitted with sepsis.

Everolimus-Induced Hypertriglyceridemia Manifesting as Acute Pancreatitis

Everolimus is used in the treatment of many advanced cancers like renal and breast cancer. Hypertriglyceridemia (HTG) is a known adverse effect of the drug. However, acute pancreatitis (AP) is not commonly reported. A 46-year-old Hispanic female with recurrent breast cancer had been treated with Everolimus (10 mg/day) for 6 weeks, who then developed elevated triglycerides (TG) and the Everolimus was stopped. Three days later, she presented to the emergency center with nausea and severe, mid-epigastric pain radiating to her back. Lab values included: sodium 127 mEq/L, lipase 795 U/L, blood glucose > 700 mg/dl, with normal calcium. The serum was milky in appearance, with TG > 1590 mg/dL. There was no history of diabetes or alcohol use. She was diagnosed with diabetic ketoacidosis (DKA) and admitted to the medical ICU for intravenous fluids, insulin drip and pain control. Despite resolution of ketoacidosis, her pain worsened and she remained anorexic. Gastroenterology was consulted and diagnosed her with AP due to HTG. After several days, her TG decreased to 336 mg/dL with above treatment, coinciding with improvement of her symptoms (Figure 1). Her diet was advanced and she was discharged with fenofibrates. TG level four months later normalized. Everolimus treatment was not re-attempted. Hypertriglyceridemia and drugs are common causes of AP. There are two main causes of HTG-induced AP (HTG-AP): primary (usually genetic or idiopathic) and secondary. The pathogenesis of HTG associated with mTOR inhibitors is unclear, but may be related to slow degradation of apolipoprotein B100 leading to dyslipidemia. Hyperlipidemia is thought to cause AP when the pancreatic lipase hydrolyzes the excess TGs circulating in the serum damaging the free fatty acids which in turn accumulate in the pancreas leading to severe inflammation of the pancreas. HTG also leads to impaired clearance of chylomicrons leading to pancreatic capillary hyperviscosity causing ischemia. HTG-induced AP may be clinically evident when TG levels exceed 1000 mg/dL. Treatment involves IV insulin, IV heparin, or plasmapheresis (in absence of hyperglycemia) with fenofibrates for long term management. Our patient likely had secondary HTG due to Everolimus. Awareness of Everolimus causing HTG-AP is important for gastroenterologists, especially those who may treat cancer patients.Figure: Timeline showing introduction of Everolimus and development of Hypertriglyceridemia.

Diabetes in remission

Diabetes in remission

Euglycemic Diabetic Ketoacidosis With Prolonged Glucosuria Associated With the Sodium-Glucose Cotransporter-2 Canagliflozin.

Sodium-glucose cotransporter-2 (SGLT2) inhibitors improve glycemic control by a reversible inhibition of the sodium-glucose cotransporters in the renal proximal tubules resulting in increased urinary glucose. This unique mechanism, independent of insulin secretion and beta cell function, has made this class of medication desirable in patients with type 2 diabetes. However in May 2015, the US Food and Drug Administration issued a safety warning pertaining to the development of diabetic ketoacidosis (DKA) with the use of SGLT2 inhibitors. DKA associated with SGLT2 inhibitors frequently develops in the absence of hyperglycemia, which makes the diagnosis more challenging. Due to the reversible inhibition of SGLT2 by this class of medication, a quick recovery of glucosuria after cessation of medication is expected. In this article, we present a case of a 50-year-old woman with type 2 diabetes who developed euglycemic DKA after initiating therapy with canagliflozin. This case of DKA associated with SGLT2 inhibitor use was unique due to her hypoglycemic presentation and persistent glucosuria. SGLT2 inhibitors such as canagliflozin may predispose patients not only to diabetic ketoacidosis but also to prolonged glucosuria.