Dehydration and insulinopenia are necessary and sufficient for euglycemic ketoacidosis in SGLT2 inhibitor-treated rats

Dehydration-induced AVP stimulates glucagon release and ketogenesis

Gliflozins, such as dapagliflozin, belong to a class of drugs that inhibit the sodium-glucose cotransporter 2. Gliflozins have been found to raise glucagon levels, a hormone secreted from pancreatic islet α-cells, which can trigger ketosis. However, the precise mechanisms through which gliflozins increase glucagon secretion remain poorly understood. In addition, gliflozins induce osmotic diuresis, resulting in increased urine volume and plasma osmolality. In this study, we investigated the hypothesis that a compensatory increase in arginine-vasopressin (AVP) mediates dapagliflozin-induced increases in glucagon in vivo. We show that dapagliflozin does not increase glucagon secretion in the perfused mouse pancreas, neither at clinical nor at supra-clinical doses. In contrast, AVP potently increases glucagon secretion. In vivo, dapagliflozin increased plasma glucagon, osmolality, and AVP. An oral load with hypertonic saline amplified dapagliflozin-induced glucagon secretion. Notably, a similar increase in glucagon could also be elicited by dehydration, evoked by 24-h water restriction. Conversely, blockade of vasopressin 1b receptor signaling, with either pharmacological antagonism or knockout of the receptor, resulted in reduced dapagliflozin-induced glucagon secretion in response to both dapagliflozin and dehydration. Finally, blocking vasopressin 1b receptor signaling in a mouse model of type 1 diabetes diminished the glucagon-promoting and ketogenic effects of dapagliflozin. Collectively, our data suggest that AVP is an important regulator of glucagon release during both drug-induced and physiological dehydration.NEW & NOTEWORTHY Gliflozin-induced ketogenic effects partly result from increased glucagon levels. This study shows that dapagliflozin-triggered glucagon secretion is not directly mediated by the pancreas but rather linked to arginine-vasopressin (AVP). Dehydration, common in diabetic ketoacidosis, elevates AVP, potentially explaining the increased ketoacidosis risk in gliflozin-treated patients. Thus, our results highlight AVP as a potential therapeutic target to mitigate the risk of ketoacidosis associated with gliflozin treatments in patients with diabetes.

Metabolic acidosis in patients with diabetes 2 undergoing cardiac surgery: The impact of SGLT2 inhibitor use: a retrospective cohort study

BACKGROUND

Sodium-glucose cotransporter 2 inhibitors (SGLT2-i) lower blood sugar and reduce cardiovascular events and kidney failure. However, there have been increasing reports of euglycaemic diabetic ketoacidosis (eDKA) linked to SGLT2-i medicines.

OBJECTIVE

Investigating the association between SGLT2-i use and the incidence of metabolic acidosis in patients with type 2 diabetes undergoing cardiac surgery.

DESIGN

A retrospective observational cohort study comprising 121 patients, with 38 in the SGLT2-i group and 83 in the control group.

SETTING

A 2-year period at Haukeland University Hospital, a tertiary regional hospital in Western Norway.

PATIENTS

Patients with type 2 diabetes undergoing cardiac surgery.

INTERVENTIONS

Collection of clinical and laboratory data, including acid/base balance parameters, surgery details and SGLT2-i use.

MAIN OUTCOME MEASURES

Base excess and anion gap measurements as indicators of ketosis development. A subgroup analysis in patients without renal failure (glomerular filtration rate > 60 ml min -1  m -2 ) .

RESULTS

Lower base excess levels and increased anion gaps were observed in the SGLT2-i group compared with controls at various time points postoperatively, with no significant differences in serum lactate levels.Twelve hours postoperatively, 41% of SGLT2-i patients without renal failure had a base excess -3 mmol l -1 or less after correction for serum lactate (indicating ketosis) compared with only 8% in the control group ( P  < 0.001). The anion gap was elevated in the SGLT2-i group compared to the control group at 12 h postoperatively ( P  = 0.018).Multivariable regression analysis identified SGLT2-i use as an independent factor associated with a lower base excess after correction for lactate levels ( P  < 0.001). Cessation of SGLT2-i medication did not correlate with the degree of acidosis.

CONCLUSION

While taking SGLT2 inhibitors, diabetic patients undergoing heart surgery are at an increased risk of ketosis and possibly metabolic acidosis. This emphasises the importance of careful observation and effective treatment strategies within this group.

A kidney-hypothalamus axis promotes compensatory glucose production in response to glycosuria

The kidneys facilitate energy conservation through reabsorption of nutrients including glucose. Almost all the filtered blood glucose is reabsorbed by the kidneys. Loss of glucose in urine (glycosuria) is offset by an increase in endogenous glucose production to maintain normal energy supply in the body. How the body senses this glucose loss and consequently enhances glucose production is unclear. Using renal Slc2a2 (also known as Glut2) knockout mice, we demonstrate that elevated glycosuria activates the hypothalamic-pituitary-adrenal axis, which in turn drives endogenous glucose production. This phenotype was attenuated by selective afferent renal denervation, indicating the involvement of the afferent nerves in promoting the compensatory increase in glucose production. In addition, through plasma proteomics analyses we observed that acute phase proteins - which are usually involved in the body's defense mechanisms against a threat - were the top candidates which were either upregulated or downregulated in renal Slc2a2 KO mice. Overall, afferent renal nerves contribute to promoting endogenous glucose production in response to elevated glycosuria and loss of glucose in urine is sensed as a biological threat in mice. These findings may be useful in improving the efficiency of drugs like SGLT2 inhibitors that are intended to treat hyperglycemia by enhancing glycosuria but are met with a compensatory increase in endogenous glucose production.

From Sweet to Sour: SGLT-2-Inhibitor-Induced Euglycemic Diabetic Ketoacidosis

Sodium-glucose cotransporter 2 (SGLT-2) inhibitors are highly selective, effective, and generally well-tolerated antihyperglycemic agents targeting the SGLT-2 transmembrane protein. Despite being primarily registered for diabetes treatment, due to their cardiorenal protective properties, SGLT-2 inhibitors caused a paradigm shift in the treatment of other diseases on the cardiorenal spectrum, becoming a fundamental part of heart failure and chronic kidney disease management. With their rapidly increasing use, there are also increased reports of a rare, often under-recognised and potentially deadly side effect, SGLT-2-inhibitor-induced euglycemic diabetic ketoacidosis (EDKA). The primary pathophysiological process behind its multifactorial aetiology comprises glucosuria and osmotic diuresis, which produce a significant carbohydrate deficit, leading to an increase in the glucagon-insulin ratio, thus resulting in accelerated ketogenesis. Although EDKA has a similar clinical presentation as diabetic ketoacidosis (DKA), the absence of the high glucose levels typically expected for DKA and the presence of urine ketone reabsorption contribute to a significant delay in its recognition and timely diagnosis. Given the broad use of SGLT-2 inhibitors, increased awareness, early recognition, and prompt identification of precipitating factors are essential. In this narrative review, we comprehensively explore the pathophysiological mechanisms of SGLT-2-inhibitor-induced EDKA, analyse its clinical manifestation, and identify the most common triggers for its development. We also discuss EDKA management and preventive strategies.

A kidney-hypothalamus axis promotes compensatory glucose production in response to glycosuria

The kidneys facilitate energy conservation through reabsorption of nutrients including glucose. Almost all the filtered blood glucose is reabsorbed by the kidneys. Loss of glucose in urine (glycosuria) is offset by an increase in endogenous glucose production to maintain normal energy supply in the body. How the body senses this glucose loss and consequently enhances glucose production is unclear. Using renal Glut2 knockout mice, we demonstrate that elevated glycosuria activates the hypothalamic-pituitary-adrenal axis, which in turn drives endogenous glucose production. This phenotype was attenuated by selective afferent renal denervation, indicating the involvement of the afferent nerves in promoting the compensatory increase in glucose production. In addition, through plasma proteomics analyses we observed that acute phase proteins - which are usually involved in body's defense mechanisms against a threat - were the top candidates which were either upregulated or downregulated in renal Glut2 KO mice. Overall, afferent renal nerves contribute to promoting endogenous glucose production in response to elevated glycosuria and loss of glucose in urine is sensed as a biological threat in mice. These findings may be useful in improving efficiency of drugs like SGLT2 inhibitors that are intended to treat hyperglycemia by enhancing glycosuria but are met with a compensatory increase in endogenous glucose production.

Glucagon secretion and its association with glycaemic control and ketogenesis during sodium-glucose cotransporter 2 inhibition by ipragliflozin in people with type 1 diabetes: Results from the multicentre, open-label, prospective study

AIM

Clinical trials showed the efficacy of sodium-glucose cotransporter 2 inhibitors for type 1 diabetes (T1D) by significant reductions in body weight and glycaemic variability, but elevated susceptibility to ketoacidosis via elevated glucagon secretion was a potential concern. The Suglat-AID evaluated glucagon responses and its associations with glycaemic control and ketogenesis before and after T1D treatment with the sodium-glucose cotransporter 2 inhibitor, ipragliflozin.

METHODS

Adults with T1D (n = 25) took 50-mg open-labelled ipragliflozin daily as adjunctive to insulin. Laboratory/clinical data including continuous glucose monitoring were collected until 12 weeks after the ipragliflozin initiation. The participants underwent a mixed-meal tolerance test (MMTT) twice [before (first MMTT) and 12 weeks after ipragliflozin treatment (second MMTT)] to evaluate responses of glucose, C-peptide, glucagon and β-hydroxybutyrate.

RESULTS

The area under the curve from fasting (0 min) to 120 min (AUC0-120min) of glucagon in second MMTT were significantly increased by 14% versus first MMTT. The fasting and postprandial β-hydroxybutyrate levels were significantly elevated in second MMTT versus first MMTT. The positive correlation between postprandial glucagon secretion and glucose excursions observed in first MMTT disappeared in second MMTT, but a negative correlation between fasting glucagon and time below range (glucose, <3.9 mmol/L) appeared in second MMTT. The percentage changes in glucagon levels (fasting and AUC0-120min) from baseline to 12 weeks were significantly correlated with those in β-hydroxybutyrate levels.

CONCLUSIONS

Ipragliflozin treatment for T1D increased postprandial glucagon secretion, which did not exacerbate postprandial hyperglycaemia but might protect against hypoglycaemia, leading to reduced glycaemic variability. The increased glucagon secretion might accelerate ketogenesis when adequate insulin is not supplied.

The association between sodium/glucose cotransporter-2 inhibitors and adverse clinical events in patients with chronic kidney disease: a systematic review and meta-analysis of randomised controlled trials

BACKGROUND

The purpose of this systematic review and meta-analysis was to evaluate the common clinical adverse events associated with sodium/glucose cotransporter-2 inhibitor (SGLT2i) use compared to placebo in patients with chronic kidney disease (CKD) with or without type 2 diabetes.

METHODS

Twelve articles were chosen via a systematic search of the PubMed, Embase, and Cochrane Library databases. We screened for randomised placebo-controlled trials. The main clinical adverse events included diabetes ketoacidosis (DKA), amputation, and volume depletion. We performed heterogeneity testing and assessment of publication bias.

RESULTS

In all, 65 600 patients were included in the analysis. Compared to placebo, SGLT2i may increase the risk of DKA and volume depletion in patients with CKD with or without type 2 diabetes. For DKA, compared with placebo, the combined effect of SGLT2i was OR 2.03 (95% CI: 1.28 to 3.23 I2: 2.3%, P: 0.420). For volume depletion, compared with placebo, the combined effect of SGLT2i was OR 1.24 (95% CI: 1.13 to 1.37 I2: 0.0%, P: 0.484). For the risk of amputation, despite low heterogeneity for amputation, the forest plot indicated no statistical significance, and thus it cannot be concluded that SGLT2i increases the risk of amputation. Compared with placebo, the combined effect of SGLT2i was OR 1.10 (95% CI: 0.94 to 1.29 I2: 0.0%, P: 0.642).

CONCLUSION

The use of SGLT2i may increase the risk of DKA and volume depletion in patients with chronic renal insufficiency with or without type 2 diabetes.

Rates of diabetic ketoacidosis with empagliflozin use during hospitalization for acute heart failure

There is concern that sodium-glucose cotransporter-2 inhibitors during hospitalization for acute heart failure (aHF) may precipitate diabetic ketoacidosis (DKA). A retrospective study of all hospitalization encounters for aHF defined by a primary HF International Classification of Diseases (ICD)-10 code in 15 Kaiser Permanente Southern California medical centers hospitalized between January 1, 2021 and August 31, 2023 was performed to describe rates of DKA with empagliflozin use. DKA was defined by the presence of either a DKA ICD-10 code or ketoacidosis lab criteria (bicarbonate <18 mmol/L and urine ketone 1+ or more or elevated serum beta-hydroxybutyrate within 12 h) during hospitalization. Among 21,630 hospital encounters (15,518 patients) for aHF, 1678 (8%) had empagliflozin use. There were 2 (0.1%) probable DKA cases in empagliflozin encounters and 15 (0.1%) in nonexposed encounters. These rates were similar when stratified by diabetes status and ejection fraction. Empagliflozin may be safe during aHF hospitalization.

Empagliflozin improves cardiac function in rats with chronic heart failure

The objective of this study is to examine the effect of empagliflozin on cardiac function in rats with chronic heart failure and the possible mechanism. Forty 6-week-old male SD rats were randomly divided into the control group, empagliflozin treatment group, and sham-operated group. SD rats in the control group and empagliflozin treatment group were subjected to ligation of the anterior descending coronary artery to induce an acute myocardial infarction model. SD rats in the sham-operated group were only subjected to threading of the anterior descending branch of the coronary artery without ligation. On the second day after surgery, the control group and sham operation group were given physiological saline by gavage, while the empagliflozin treatment group was given empagliflozin (30 mg/kg/day) by gavage. Sixteen weeks later, cardiac function, intracellular reactive oxygen species (ROS) levels, mitochondrial membrane potential (MMP), serum brain natriuretic peptide, hypersensitive C-reactive protein (hs-CRP), iNOS expression levels, and myocardial morphological changes were observed. Compared with that in the control group, heart function in the empagliflozin-treated group was significantly improved, MMP was increased, intracellular ROS levels were decreased, and NT-proBNP and hs-CRP were significantly reduced, and HE staining showed that the cell oedema was less than that in the control group, tissue arrangement was more orderly, and iNOS expression was inhibited. Empagliflozin can improve cardiac function in rats with chronic heart failure, and the mechanism may involve inhibiting inflammation, reducing myocardial oxidative stress, and improving myocardial fibrosis.

Prevalence of sodium-glucose transporter 2 inhibitor-associated diabetic ketoacidosis in real-world data: A systematic review and meta-analysis

BACKGROUND

The U.S. Food and Drug Administration (FDA) revised the labels of sodium-glucose transporter 2 (SGLT2) inhibitors in December 2015 to inform users regarding the risk of diabetic ketoacidosis (DKA). As more drugs of this class are approved and their indications are expanded, this serious adverse effect has been increasingly reported.

OBJECTIVE

This review evaluated observational studies to inform the prevalence of SGLT2-inhibitor-associated DKA compared with other antihyperglycemic agents.

METHODS

A systematic review was conducted in PubMed and EMBASE until 19 July 2022 (PROSPERO: CRD42022385425). We included published retrospective cohort active comparator/new user (ACNU) and prevalent new user studies assessing SGLT2-inhibitor-associated DKA prevalence in adult patients with type 2 diabetes mellitus (T2DM) against active comparators. We excluded studies which lacked 1:1 propensity score matching. The JBI Checklist for Cohort Studies guided the risk-of-bias assessments. Meta-analysis was conducted based on the inverse variance method in R software.

RESULTS

Sixteen studies with a sample of 2,956,100 nonunique patients met the inclusion criteria. Most studies were conducted in North America (n = 9) and adopted the ACNU design (n = 15). Meta-analysis of 14 studies identified 33% higher DKA risk associated with SGLT2 inhibitors (HR = 1.33, 95% CI: 1.14-1.55, P < 0.01). Meta-regression analysis identified the study location (P = 0.02), analysis principle (P < 0.001), exclusion of chronic comorbidities (P = 0.007), and canagliflozin (P = 0.04) as significant moderator variables.

CONCLUSIONS

Despite limitations related to heterogeneity, generalizability, and misclassification, the results of this study show that SGLT2 inhibitors increase the prevalence of DKA among adult T2DM patients in the real world. The findings supplement evidence from randomized controlled trials (RCTs) and call for continued vigilance.

Sodium-Glucose Cotransporter-2 Inhibitor-Induced Euglycemic Diabetic Ketoacidosis in a Type 2 Diabetic Patient

Euglycemic diabetic ketoacidosis (euDKA) is a life-threatening metabolic complication typically associated with type 1 diabetes mellitus (T1DM). However, its occurrence in type 2 diabetes mellitus (T2DM) remains exceptionally rare. We present a case report detailing the unusual manifestation of euDKA in a patient with T2DM following the initiation of treatment with a sodium-glucose cotransporter-2 (SGLT-2) inhibitor. The patient, a 67-year-old female with a history of T2DM and well-controlled blood glucose levels, was commenced on an SGLT-2 inhibitor as part of her antidiabetic regimen just two weeks prior. Subsequently, the patient developed euDKA despite maintaining near-normal glycemic levels. This paradoxical presentation challenges the conventional understanding of DKA in T2DM and underscores the need for heightened clinical awareness. EuDKA associated with SGLT-2 inhibitors is an infrequently reported phenomenon, further complicating the clinical landscape. This case contributes to the growing evidence suggesting an association between SGLT-2 inhibitors and the development of euDKA in patients with T2DM. The rarity of this occurrence necessitates a thorough exploration of potential risk factors and underlying mechanisms.

Critical Analysis of the Effects of SGLT2 Inhibitors on Renal Tubular Sodium, Water and Chloride Homeostasis and Their Role in Influencing Heart Failure Outcomes

SGLT2 (sodium-glucose cotransporter 2) inhibitors interfere with the reabsorption of glucose and sodium in the early proximal renal tubule, but the magnitude and duration of any ensuing natriuretic or diuretic effect are the result of an interplay between the degree of upregulation of SGLT2 and sodium-hydrogen exchanger 3, the extent to which downstream compensatory tubular mechanisms are activated, and (potentially) the volume set point in individual patients. A comprehensive review and synthesis of available studies reveals several renal response patterns with substantial variation across studies and clinical settings. However, the common observation is an absence of a large acute or chronic diuresis or natriuresis with these agents, either when given alone or combined with other diuretics. This limited response results from the fact that renal compensation to these drugs is rapid and nearly complete within a few days or weeks, preventing progressive volume losses. Nevertheless, the finding that fractional excretion of glucose and lithium (the latter being a marker of proximal sodium reabsorption) persists during long-term treatment with SGLT2 inhibitors indicates that pharmacological tolerance to the effects of these drugs at the level of the proximal tubule does not meaningfully occur. This persistent proximal tubular effect of SGLT2 inhibitors can be hypothesized to produce a durable improvement in the internal set point for volume homeostasis, which may become clinically important during times of fluid expansion. However, it is difficult to know whether a treatment-related change in the volume set point actually occurs or contributes to the effect of these drugs to reduce the risk of major heart failure events. SGLT2 inhibitors exert cardioprotective effects by a direct effect on cardiomyocytes that is independent of the presence of or binding to SGLT2 or the actions of these drugs on the proximal renal tubule. Nevertheless, changes in the volume set point mediated by SGLT2 inhibitors might potentially act cooperatively with the direct favorable molecular and cellular effects of these drugs on cardiomyocytes to mediate their benefits on the development and clinical course of heart failure.

Euglycemic diabetic ketoacidosis caused by empagliflozin complicated by failure to thrive in a geriatric patient

Euglycemic diabetic ketoacidosis (euDKA) is a rare but deadly complication of sodium-glucose cotransport-2 (SGLT-2) inhibitors. Primarily indicated for the treatment of Type 2 Diabetes Mellitus, the incidence of euDKA is expected to rise as SGLT-2 inhibitors become a mainstay therapy for diabetics with heart failure. Diagnosis of euDKA can be difficult given the presence of normoglycemia and is especially challenging among geriatric patients that are complicated by additional comorbidities. We present a case of an elderly male with multiple comorbidities who presented for dehydration and altered mentation from a nursing home facility. Laboratory investigations showed signs of acute renal failure, uremia, electrolyte abnormalities, and severe metabolic acidosis due to high levels of plasma beta-hydroxybutyrate. He was admitted to the medical intensive care unit (ICU) for further management. A presumptive diagnosis of euDKA was strongly suspected due to his laboratory data and medication reconciliation which revealed the recent initiation of empagliflozin. The patient was promptly started on a standardized treatment protocol for DKA with continuous infusion of regular insulin with strict glucose monitoring, along with intravenous fluids, and a small dose of sodium bicarbonate infusion as per current standard guidelines. With the rapid improvement in symptoms and metabolic derangements, the diagnosis was confirmed. Geriatric patients from nursing home facilities are a high-risk cohort who if not properly cared for by nursing staff can develop dehydration, malnutrition and worsening frailty including sarcopenia that exposes them to increased risk of medication side effects, such as euDKA. Clinicians should consider euDKA in their differential diagnosis in elderly patients with overt or relative insulinopenia who are receiving SGLT-2 inhibitors when presenting with acute changes in health and mentation.

Distinct Mechanisms Responsible for the Increase in Glucose Production and Ketone Formation Caused by Empagliflozin in T2DM Patients

OBJECTIVE

To examine the mechanisms responsible for the increase in glucose and ketone production caused by empagliflozin in patients with type 2 diabetes mellitus (T2DM).

RESEARCH DESIGN AND METHODS

Twelve subjects with T2DM participated in two studies performed in random order. In study 1, endogenous glucose production (EGP) was measured with 8-h infusion of 6,6,D2-glucose. Three hours after the start of 6,6,D2-glucose infusion, subjects ingested 25 mg empagliflozin (n = 8) or placebo (n = 4), and norepinephrine (NE) turnover was measured before and after empagliflozin ingestion with 3H-NE infusion. Study 2 was similar to study 1 but performed under pancreatic clamp conditions.

RESULTS

When empagliflozin was ingested under fasting conditions, EGP increased by 31% in association with a decrease in plasma glucose (-34 mg/dL) and insulin (-52%) concentrations and increases in plasma glucagon (+19%), free fatty acid (FFA) (+29%), and β-hydroxybutyrate (+48%) concentrations. When empagliflozin was ingested under pancreatic clamp conditions, plasma insulin and glucagon concentrations remained unchanged, and the increase in plasma FFA and ketone concentrations was completely blocked, while the increase in EGP persisted. Total-body NE turnover rate was greater in subjects receiving empagliflozin (+67%) compared with placebo under both fasting and pancreatic clamp conditions. No difference in plasma NE concentration was observed in either study.

CONCLUSIONS

The decrease in plasma insulin and increase in plasma glucagon concentration caused by empagliflozin is responsible for the increase in plasma FFA concentration and ketone production. The increase in EGP caused by empagliflozin is independent of the change in plasma insulin or glucagon concentrations and is likely explained by the increase in NE turnover.

Safety and effectiveness of the sodium-glucose cotransporter inhibitor bexagliflozin in cats newly diagnosed with diabetes mellitus

BACKGROUND

Bexagliflozin is a sodium-glucose cotransporter 2 (SGLT2) inhibitor. A pilot study has shown that bexagliflozin can decrease dependence on exogenous insulin in cats with diabetes mellitus (DM).

OBJECTIVE

To evaluate the safety and effectiveness of bexagliflozin as a monotherapy for DM in previously untreated cats.

ANIMALS

Eighty-four client-owned cats.

METHODS

Historically controlled prospective open-label clinical trial. Cats were dosed PO with 15 mg bexagliflozin once daily for 56 days, with a 124-day extension to evaluate safety and treatment effect durability. The primary endpoint was the proportion of cats experiencing a decrease in hyperglycemia and improvement in clinical signs of hyperglycemia from baseline on day 56.

RESULTS

Of 84 enrolled cats, 81 were evaluable on day 56, and 68 (84.0%) were treatment successes. Decreases in mean serum glucose, fructosamine, and β-hydroxybutyrate (β-OHB) concentrations were observed, and investigator assessments of cat neurological status, musculature, and hair coat quality improved. Owner evaluations of both cat and owner quality of life were favorable. The fructosamine half-life in diabetic cats was found to be 6.8 days. Commonly observed adverse events included emesis, diarrhea, anorexia, lethargy, and dehydration. Eight cats experienced serious adverse events, 3 of which led to death or euthanasia. The most important adverse event was euglycemic diabetic ketoacidosis, diagnosed in 3 cats and presumed present in a fourth.

CONCLUSION AND CLINICAL IMPORTANCE

Bexagliflozin decreased hyperglycemia and observed clinical signs in cats newly diagnosed with DM. As a once-daily PO medication, bexagliflozin may simplify management of DM in cats.

What is the utility of blood beta-hydroxybutyrate measurements in emergency department in patients without diabetes: a systematic review

BACKGROUND

Ketones are synthesised as an alternative fuel source during times of energy restriction. In the absence of a hyperglycemic emergency, ketosis in patients presenting to the emergency department (ED) may indicate reduced carbohydrate intake. In the perioperative setting, excess fasting with ketosis is associated with worse outcomes; however, whether ketosis in patients without diabetes presenting to ED is also associated with worse outcomes is unclear. This systematic review aims to examine the evidence for ketosis in predicting the need for hospital admission in patients without diabetes, presenting to the ED.

METHODS

A systematic review was performed using PRISMA guidelines. We searched electronic bases (OVID-Medline, OVID-EMBASE, Scopus and PubMed) up to December 2022. Eligible studies included children or adults without diabetes presenting to the ED where a point-of-care capillary beta-hydroxybutyrate (BHB) was measured and compared to outcomes including the need for admission. Outcome measures included need for admission and length of stay. Content analysis was performed systematically; bias and certainty assessed using standard tools.

RESULTS

The literature search found 17,133 citations, 14,965 papers were subjected to title and abstract screening. The full text of 62 eligible studies were reviewed. Seven articles met the inclusion criteria. Six studies were conducted solely in the paediatric population, and of these, four were limited to children presenting with gastroenteritis symptoms. Median BHB was higher in children requiring hospital admission with an AUC of 0.64-0.65 across two studies. There was a weak correlation between BHB and dehydration score or duration of symptoms. The single study in adults, limited to stroke presentations, observed no relationship between BHB and neurological deficit at presentation. All studies were at risk of bias using the Newcastle-Ottawa Scale and was assessed of "very low" to "low" quality due to their study design in the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. Heterogeneity amongst selected studies precluded meta-analysis.

CONCLUSION

The evidence for any utility of BHB measurement in the ED in absence of diabetes is limited to the paediatric population, specifically children presenting with symptoms of gastroenteritis. Any role in adults remains unexplored.

Empagliflozin-associated postoperative mixed metabolic acidosis. Case report and review of pathogenesis

BACKGROUND

Euglycemic diabetic ketoacidosis associated with SGLT2 inhibitors is a rare, relatively new and potentially fatal clinical entity, characterized by metabolic acidosis with normal or only moderately elevated glycemia. The mechanisms are not fully understood but involve increased ketogenesis and complex renal metabolic dysfunction, resulting in both ketoacidosis and hyperchloremic acidosis. We report a rare case of fatal empagliflozin-associated acidosis with profound hyperchloremia and review its pathogenesis.

CASE PRESENTATION

A patient with type 2 diabetes mellitus treated with empagliflozin underwent an elective hip replacement surgery. Since day 4 after surgery, he felt generally unwell, leading to cardiac arrest on the day 5. Empagliflozin-associated euglycemic diabetic ketoacidosis with severe hyperchloremic acidosis was identified as the cause of the cardiac arrest.

CONCLUSIONS

This unique case documents the possibility of severe SGLT2 inhibitor-associated mixed metabolic acidosis with a predominant hyperchloremic component. Awareness of this possibility and a high index of suspicion are crucial for correct and early diagnosis.

Life-Threatening Acidosis With Metformin and Dapagliflozin Combination Therapy: A Case Report

Euglycemic keto-acidosis is a known complication of dapagliflozin. However, acidosis can be life-threatening when dapagliflozin is used as a combination therapy with metformin. Our patient was a 64-year-old male, with a history of well-controlled type 2 diabetes mellitus on metformin and dapagliflozin, admitted with vomiting and diarrhea for several days. On presentation, the patient was hypotensive and severely acidotic (pH < 6.7; bicarbonate <5 mmol/L) with an anion gap of 47. Other labs included elevated lactate (19.48 mmol/L), creatinine of 10.39 mg/dL, and elevated beta-hydroxybutyrate levels. The patient was intubated and started on dual vasopressors, insulin drip, and i.v. hydration. Due to worsening acidosis, bicarbonate drip and, subsequently, continuous dialysis was started. The patient's acidosis normalized after two days of dialysis, and he was extubated by day three and discharged by day seven. Dapagliflozin leads to keto-acidosis due to increased hepatic ketogenesis and adipose tissue lipolysis. It also promotes natriuresis, glycosuria, and free water loss. Recurrent vomiting and poor oral intake with concomitant lactic acidosis with metformin can lead to life-threatening acidosis. Clinicians should remain cognizant of the possibility of severe acidosis with the combination therapy of dapagliflozin and metformin in severe dehydration. Adequate hydration may prevent this life-threatening complication.

From Skepticism to Hope: The Evolving Concept of the Initiation and Use of Sodium-Glucose Cotransporter 2 Inhibitors in Hospitalized Patients

The management of hyperglycemia in patients admitted to hospital is mainly based on insulin therapy. However, the positive and rapid effects of sodium-glucose cotransporter 2 inhibitors (SGLT2i) on cardiorenal outcomes raises the possibility that they might confer benefits to hospitalized patients. In recent, well designed, randomized trials (SOLOIST-WHF and EMPULSE) recruiting inpatients with heart failure (HF), SGLT2i demonstrated the potential to improve survival and quality of life and reduce the number of HF events, time to first HF event, hospitalizations, and urgent visits for HF compared with placebo. They were also well tolerated, whereas incidence of diabetic ketoacidosis was low. In EMBODY, empagliflozin was shown to be protective against the deleterious effects of cardiac injury in patients with acute myocardial infarction. In DARE-19, the administration of dapagliflozin to inpatients with cardiometabolic risk factors and COVID-19 was based on the hypothesis that the anti-inflammatory properties of SGLT2i could alleviate organ damage. Although the findings did not reach statistical significance, the efficacy and safety profiles of the drug were encouraging. These promising findings in the field of cardiometabolic medicine set the stage for future research to explore whether the benefits of gliflozins can expand to inpatients with non-cardiometabolic disorders, including sepsis, cirrhotic ascites, and malignancies. The concept of inpatient use of SGLT2i has evolved greatly over the past few years. The latest evidence suggests that SGLT2i may be effective and safe in the hospital setting, provided patients are carefully selected and closely monitored. Real-world data will prove whether present hope about inpatient use of gliflozins will transform into future confidence.

The SGLT2 Inhibitor Dapagliflozin Increases the Oxidation of Ingested Fatty Acids to Ketones in Type 2 Diabetes

OBJECTIVE

To investigate the mechanism for increased ketogenesis following treatment with the SGLT2 inhibitor dapagliflozin in people with type 2 diabetes.

RESEARCH DESIGN AND METHODS

The design was a double-blind, placebo-controlled, crossover study with a 4-week washout period. Participants received dapagliflozin or placebo in random order for 4 weeks. After each treatment, they ingested 30 mL of olive oil containing [U-13C]palmitate to measure ketogenesis, with blood sampling for 480 min. Stable isotopes of glucose and glycerol were infused to measure glucose flux and lipolysis, respectively, at 450-480 min.

RESULTS

Glucose excretion rate was higher and peripheral glucose uptake lower with dapagliflozin than placebo. Plasma β-hydroxybutyrate (BOHB) concentrations and [13C2]BOHB concentrations were higher and glucose concentrations lower with dapagliflozin than placebo. Nonesterified fatty acids (NEFAs) were higher with dapagliflozin at 300 and 420 min, but lipolysis at 450-480 min was not different. Triacylglycerol at all time points and endogenous glucose production rate at 450-480 min were not different between treatments.

CONCLUSIONS

The increase in ketone enrichment from the ingested palmitic acid tracer suggests that meal-derived fatty acids contribute to the increase in ketones during treatment with dapagliflozin. The increase in BOHB concentration with dapagliflozin occurred with only minimal changes in plasma NEFA concentration and no change in lipolysis. This finding suggests a metabolic switch to increase ketogenesis within the liver.

Loss of function of renal Glut2 reverses hyperglycaemia and normalises body weight in mouse models of diabetes and obesity

AIMS/HYPOTHESIS

Renal GLUT2 is increased in diabetes, thereby enhancing glucose reabsorption and worsening hyperglycaemia. Here, we determined whether loss of Glut2 (also known as Slc2a2) specifically in the kidneys would reverse hyperglycaemia and normalise body weight in mouse models of diabetes and obesity.

METHODS

We used the tamoxifen-inducible CreERT2-Lox system in mice to knockout Glut2 specifically in the kidneys (Ks-Glut2 KO) to establish the contribution of renal GLUT2 to systemic glucose homeostasis in health and in insulin-dependent as well as non-insulin-dependent diabetes. We measured circulating glucose and insulin levels in response to OGTT or IVGTT under different experimental conditions in the Ks-Glut2 KO and their control mice. Moreover, we quantified urine glucose levels to explain the phenotype of the mice independently of insulin actions. We also used a transcription factor array to identify mechanisms underlying the crosstalk between renal GLUT2 and sodium-glucose cotransporter 2 (SGLT2).

RESULTS

The Ks-Glut2 KO mice exhibited improved glucose tolerance and massive glucosuria. Interestingly, this improvement in blood glucose control was eliminated when we knocked out Glut2 in the liver in addition to the kidneys, suggesting that the improvement is attributable to the lack of renal GLUT2. Remarkably, induction of renal Glut2 deficiency reversed hyperglycaemia and normalised body weight in mouse models of diabetes and obesity. Longitudinal monitoring of renal glucose transporters revealed that Sglt2 (also known as Slc5a2) expression was almost abolished 3 weeks after inducing renal Glut2 deficiency. To identify a molecular basis for this crosstalk, we screened for renal transcription factors that were downregulated in the Ks-Glut2 KO mice. Hnf1α (also known as Hnf1a) was among the genes most downregulated and its recovery restored Sglt2 expression in primary renal proximal tubular cells isolated from the Ks-Glut2 KO mice.

CONCLUSIONS/INTERPRETATION

Altogether, these results demonstrate a novel crosstalk between renal GLUT2 and SGLT2 in regulating systemic glucose homeostasis via glucose reabsorption. Our findings also indicate that inhibiting renal GLUT2 is a potential therapy for diabetes and obesity.

Dapagliflozin mitigates ovalbumin-prompted airway inflammatory-oxidative successions and associated bronchospasm in a rat model of allergic asthma

BACKGROUND

Asthma is a chronic inflammatory lung disease that universally affects millions of people. Despite numerous well-defined medications, asthma is poorly managed. This study aims to clarify the potential therapeutic effect of Dapagliflozin (DAPA) against lung inflammation, oxidative stress, and associated bronchospasm in OVA-sensitized rat asthma model.

RESEARCH DESIGN AND METHODS

Twenty-five rats were allocated into (Control, Asthma, DEXA, DAPA, and DAPA+DEXA). All treatments were administered orally once a day for two weeks. The BALF levels of IL-17, TNFα, IL-1β, and MCP-1 were determined to assess airway inflammation. For oxidative stress determination, BALF MDA levels and TAC were measured. The BALF S100A4 level and NO/sGC/cGMP pathway were detected. Lung histopathological findings and immunohistochemical investigation of eNOS and iNOS activities were recorded.

RESULTS

DAPA significantly reduced (p < 0.001) airway inflammatory-oxidative markers (IL-17, TNFα, IL-1β, MCP1, and MDA), but increased (p < 0.001) TAC, and mitigated bronchospasm by activating NO/sGC/cGMP and reducing S100A4 (p < 0.001). The biochemical and western blot studies were supported by histopathological and immunohistochemical investigations.

CONCLUSIONS

DAPA presents a new prospective possibility for future asthma therapy due to its anti-inflammatory, anti-oxidant, and bronchodilator properties. DAPA has the property of reducing Dexamethasone (DEXA)-associated unfavorable effects during asthma treatment.

The Effects of Star Fruit (Averrhoa carambola Linn.) Extract on Body Mass Index, Fasting Blood Glucose, and Triglyceride Levels in Male Rats with Obesity and Type 2 Diabetes Mellitus

BACKGROUND: Obesity is the main risk factor of diabetes by which induces insulin resistance. Epicatechin gallate can virtually interact with sodium-glucose co-transporter 2 as same as dapagliflozin and is found in green tea and star fruits. AIM: This study aimed to investigate the effects of methanol extract of star fruit (MES) on body weight (BW), body mass index (BMI), fasting blood glucose (FBG), and triglyceride levels in male rats with obesity and type 2 diabetes mellitus (T2DM). METHODS: Twenty-four male Sprague-Dawley rats were randomly assigned to normal and high-fat diet (HFD) groups. Obesity was induced with a HFD diet for 5 weeks and followed by induction of T2DM with 230 mg/kg BW nicotinamide and 65 mg/kg BW streptozotocin injections. Twenty-one obesity and T2DM rats were randomly assigned to negative control (n = 3) and the remaining rats in the MES1-3 groups, which were given 250, 500, and 1000 mg/kg BW/day MES. Data of BW, BMI, FBG, and triglyceride levels were collected at day 1, 14, and 28 interventions. Data were statistically analyzed using parametric and non-parametric tests with p < 0.05 considered significant. RESULTS: The MES3 group (282.56 ± 10.75 g) had significantly lower mean BW than the MES2 group (331.33 ± 13.17 g, p = 0.035). The duration of MES administration significantly decreased BW (p = 0.009) and BMI (p = 0.034) compared with the negative control. The mean triglyceride levels in MES1 (93.72 ± 53.69 mg/dl, p = 0.020), MES2 (71.98 ± 35.72 mg/dl, p = 0.025), and MES3 (56.68 ± 16.37 mg/dl, p = 0.020) groups significantly lower than the control group (1042.13 ± 681.74 mg/dl) on day 14. The mean FBG levels in MES1 (437.85 ± 33.04 mg/dl) and MES2 (353 ± 33.04 mg/dl) groups were also lower than the control group (470.97 ± 33.04 mg/dl). CONCLUSION: Administrations of 250, 500, and 1000 mg/kg BW/day MES decrease BW, BMI, and triglyceride level but increase FBG level in male rats with obesity and T2DM for 14 and 28 days.

Insulin and glucose infusion could prevent euglycemic diabetic ketoacidosis associated with sodium-glucose cotransporter 2 inhibitors

Perioperative euglycemic diabetic ketoacidosis (euDKA) is a serious adverse effect of sodium-glucose cotransporter 2 inhibitor (SGLT2i) treatment. We observed perioperative euDKA immediately after discontinuing insulin infusion that was started during surgery in a patient with type 2 diabetes mellitus (T2DM) for whom empagliflozin could not be withdrawn before emergency off-pump coronary artery bypass grafting (OPCAB). Insulin infusion that was started during surgery unexpectedly prevented euDKA until its discontinuation. Therefore, we hypothesized that insulin and glucose infusion initiated at the start of emergency surgery in patients receiving SGLT2is prevents perioperative euDKA. We implemented this strategy during emergency OPCAB in another patient with T2DM who received empagliflozin 2 days before surgery and observed that the patient did not develop perioperative euDKA. With the increasing use of SGLT2is, surgeons may encounter more SGLT2i users who require emergency surgeries. The administration of insulin and glucose infusion in advance emergency surgery can prevent perioperative euDKA.

Effects and mechanisms of SGLT2 inhibitors on the NLRP3 inflammasome, with a focus on atherosclerosis

Atherosclerosis is a lipid-driven chronic inflammatory disease that is widespread in the walls of large and medium-sized arteries. Its pathogenesis is not fully understood. The currently known pathogenesis includes activation of pro-inflammatory signaling pathways in the body, increased oxidative stress, and increased expression of cytokines/chemokines. In the innate immune response, inflammatory vesicles are an important component with the ability to promote the expression and maturation of inflammatory factors, release large amounts of inflammatory cytokines, trigger a cascade of inflammatory responses, and clear pathogens and damaged cells. Studies in the last few years have demonstrated that NLRP3 inflammatory vesicles play a crucial role in the development of atherosclerosis as well as its complications. Several studies have shown that NLRP3 binding to ligands promotes inflammasome formation, activates caspase-1, and ultimately promotes its maturation and the maturation and production of IL-1β and IL-18. IL-1β and IL-18 are considered to be the two most prominent inflammatory cytokines in the inflammasome that promote the development of atherosclerosis. SGLT2 inhibitors are novel hypoglycemic agents that also have significant antiatherosclerotic effects. However, their exact mechanism is not yet clear. This article is a review of the literature on the effects and mechanisms of SGLT2 inhibitors on the NLRP3 inflammasome, focusing on their role in antiatherosclerosis.

Clinical and biochemical characteristics and analysis of risk factors for euglycaemic diabetic ketoacidosis in type 2 diabetic individuals treated with SGLT2 inhibitors: A review of 72 cases over a 4.5-year period

BACKGROUND AND AIMS

To study euglycemic diabetic ketoacidosis (euDKA) outcomes associated with sodium-glucose co-transporter 2 inhibitors (SGLT2is) METHODS: Review of 72 euDKA cases in T2DM between September 2015 and January 2020 (PUBMED).

RESULTS

euDKA could occur at any time during SGLT2is treatment, with nausea, abdominal pain and vomiting as main symptoms. Hyperglycemia did not correlate with pH and β-hydroxybutyrates. Low pH and high β-hydroxybutyrates were significantly associated with euDKA. In biguanides users, acidosis was unrelated to lactic acidosis. euDKA occurred during fasting, surgery, acute infection, insulin deprivation (endogenous or exogenous).

CONCLUSIONS

These data support avoidance of euDKA risk states in SGLT2i users.

SGLT2 Inhibition by Dapagliflozin Attenuates Diabetic Ketoacidosis in Mice with Type-1 Diabetes

BACKGROUND

SGLT2 inhibitors increase plasma ketone concentrations. It has been suggested that insulinopenia, along with an increase in the counter-regulatory hormones epinephrine, corticosterone, glucagon and growth hormone, can induce ketoacidosis, especially in type-1 diabetes (T1DM). Dehydration precipitates SGLT2 inhibitor-induced ketoacidosis in type-2 diabetes. We studied the effects of dapagliflozin and water deprivation on the development of ketoacidosis and the associated signaling pathways in T1DM mice.

METHODS

C57BL/6 mice were fed a high-fat diet. After 7 days, some mice received intraperitoneal injection of streptozocin + alloxan (STZ/ALX). The treatment groups were control + water at lib; control + dapagloflozin + water at lib; control + dapagloflozin + water deprivation; STZ/ALX + water at lib; STZ/ALX + water deprivation; STZ/ALX + dapagloflozin + water at lib; STZ/ALX + dapagloflozin + water deprivation. Dapagliflozin was given for 7 days. In the morning of day 18, food was removed, and water was removed in the water deprivation groups. ELISA, rt-PCR, and immunoblotting were used to assess blood, heart, liver, white and brown adipose tissues.

RESULTS

The T1DM mice had ketoacidosis even without water deprivation. Water deprivation increased plasma levels of β-hydroxybutyrate, acetoacetate, corticosterone, and epinephrine and reduced the levels of adiponectin in T1DM mice. Interleukin (IL) 1β, IL-6, IL-8, and TNFα were also increased in the T1DM mice with water deprivation. Dapagliflozin attenuated the changes in the T1DM mice without and with water deprivation. Likewise, water deprivation increased the activation of the inflammasome in the heart, liver, and white fat of the T1DM mice and dapagliflozin attenuated these changes. Dapagliflozin reduced the mRNA levels of glucagon receptors in the liver and the increase in GPR109a in white and brown fat. In the liver, dapagliflozin increased AMPK phosphorylation, and attenuated the phosphorylation of TBK1 and the activation of NFκB.

CONCLUSIONS

Dapagliflozin reduced ketone body levels and attenuated the activation of NFκB and the activation of the inflammasome in T1DM mice with ketoacidosis.

Euglycemic Ketoacidosis as a Complication of SGLT2 Inhibitor Therapy

Sodium-glucose cotransporter-2 (SGLT2) inhibitors are drugs designed to lower plasma glucose concentration by inhibiting Na+-glucose-coupled transport in the proximal tubule. Clinical trials demonstrate these drugs have favorable effects on cardiovascular outcomes to include slowing the progression of CKD. Although most patients tolerate these drugs, a potential complication is development of ketoacidosis, often with a normal or only a minimally elevated plasma glucose concentration. Inhibition of sodium-glucose cotransporter-2 in the proximal tubule alters kidney ATP turnover so that filtered ketoacids are preferentially excreted as Na+ or K+ salts, leading to indirect loss of bicarbonate from the body and systemic acidosis under conditions of increased ketogenesis. Risk factors include reductions in insulin dose, increased insulin demand, metabolic stress, low carbohydrate intake, women, and latent autoimmune diabetes of adulthood. The lack of hyperglycemia and nonspecific symptoms of ketoacidosis can lead to delays in diagnosis. Treatment strategies and various precautions are discussed that can decrease the likelihood of this complication.

Impact of Sodium-Glucose Co-Transporter 2 Inhibitors on Cardiac Protection

Sodium–glucose co-transporter 2 (SGLT2) inhibitors have been approved as a new class of anti-diabetic drugs for type 2 diabetes mellitus (T2DM). The SGLT2 inhibitors reduce glucose reabsorption through renal systems, thus improving glycemic control in all stages of diabetes mellitus, independent of insulin. This class of drugs has the advantages of no clinically relevant hypoglycemia and working in synergy when combined with currently available anti-diabetic drugs. While improving sugar level control in these patients, SGLT2 inhibitors also have the advantages of blood-pressure improvement and bodyweight reduction, with potential cardiac and renal protection. In randomized control trials for patients with diabetes, SGLT2 inhibitors not only improved cardiovascular and renal outcomes, but also hospitalization for heart failure, with this effect extending to those without diabetes mellitus. Recently, dynamic communication between autophagy and the innate immune system with Beclin 1-TLR9-SIRT3 complexes in response to SGLT2 inhibitors that may serve as a potential treatment strategy for heart failure was discovered. In this review, the background molecular pathways leading to the clinical benefits are examined in this new class of anti-diabetic drugs, the SGLT2 inhibitors.

SGLT-2 inhibitors associated euglycemic and hyperglycemic DKA in a multicentric cohort

Euglycemic diabetic ketoacidosis (EuDKA) secondary to Sodium-glucose co-transporter-2 inhibitors (SGLT2i) in type 2 diabetes mellitus (T2D) is a rare but increasingly reported phenomenon. Not much is known about the burden of EuDKA in patients on SGLT2i or the associated factors. This retrospective cohort study tries to delineate the differences in factors associated with the development of EuDKA as compared to hyperglycemic DKA. We conducted a multicentre, retrospective study across three tertiary care centers under Weill Cornell affiliated-Hamad Medical Corporation, Qatar. The cohort comprised of T2D patients on SGLT2i who developed DKA between January 2015 to December 2020. The differences between the subjects who developed EuDKA or hyperglycaemic DKA (hDKA) were analyzed. A total of 9940 T2D patients were on SGLT2i during 2015-2020, out of which 43 developed DKA (0.43%). 25 developed EuKDA, whereas 18 had hDKA. The point prevalence of EuDKA in our cohort was 58.1%. EuDKA was most common in patients using canagliflozin, followed by empagliflozin and Dapagliflozin (100%, 77%, and 48.3%, respectively). Overall, infection (32.6%) was the most common trigger for DKA, followed by insulin non-compliance (13.7%). Infection was the only risk factor with a significant point estimate between the two groups, being more common in hDKA patients (p-value 0.006, RR 2.53, 95% CI 1.07-5.98). Canagliflozin had the strongest association with the development of EuDKA and was associated with the highest medical intensive care unit (MICU) admission rates (66.6%). In T2D patients on SGLT2i, infection is probably associated with an increased risk of developing EuDKA. The differential role of individual SGLT2i analogs is less clear and will need exploration by more extensive prospective studies.

In Vivo Estimation of Ketogenesis Using Metabolic Flux Analysis-Technical Aspects and Model Interpretation

Ketogenesis occurs in liver mitochondria where acetyl-CoA molecules, derived from lipid oxidation, are condensed into acetoacetate (AcAc) and reduced to β-hydroxybutyrate (BHB). During carbohydrate scarcity, these two ketones are released into circulation at high rates and used as oxidative fuels in peripheral tissues. Despite their physiological relevance and emerging roles in a variety of diseases, endogenous ketone production is rarely measured in vivo using tracer approaches. Accurate determination of this flux requires a two-pool model, simultaneous BHB and AcAc tracers, and special consideration for the stability of the AcAc tracer and analyte. We describe the implementation of a two-pool model using a metabolic flux analysis (MFA) approach that simultaneously regresses liquid chromatography-tandem mass spectrometry (LC-MS/MS) ketone isotopologues and tracer infusion rates. Additionally, ¹H NMR real-time reaction monitoring was used to evaluate AcAc tracer and analyte stability during infusion and sample analysis, which were critical for accurate flux calculations. The approach quantifies AcAc and BHB pool sizes and their rates of appearance, disposal, and exchange. Regression analysis provides confidence intervals and detects potential errors in experimental data. Complications for the physiological interpretation of individual ketone fluxes are discussed.

Sodium-Glucose Cotransporter-2 Inhibitors and Risk of Diabetic Ketoacidosis Among Adults With Type 2 Diabetes: A Systematic Review and Meta-Analysis

OBJECTIVES

The magnitude and precision regarding the risk of diabetic ketoacidosis (DKA) with sodium-glucose cotransporter-2 (SGLT2) inhibitors is unclear. Thus, we examined the risk of DKA with SGLT2 inhibitors in both observational studies and large clinical trials.

METHODS

Searches were performed in PubMed, Embase, CENTRAL and Google Scholar (from inception to April 15, 2019) without language restrictions, including conference proceedings and reference lists. Study selection consisted of randomized controlled trials and observational studies that quantified the rate of DKA with an SGLT2 inhibitor in comparison to other diabetes medications or placebo. Two independent investigators abstracted the study data and assessed the quality of evidence. Data were pooled using random effects models with the Hartung-Knapp-Sidik-Jonkman method. Absolute event rates and hazard ratios for DKA were extracted from each study.

RESULTS

Seven randomized trials encompassing 42,375 participants and 5 cohort studies encompassing 318,636 participants were selected. Among the 7 randomized controlled trials, the absolute rate of DKA among patients randomized to an SGLT2 inhibitor ranged from 0.6 to 2.2 events per 1,000 person years. Four randomized trials were included in the meta-analysis and, compared with placebo or comparator medication, SGLT2 inhibitors had a 2.5-fold higher risk of DKA (relative risk [RR], 2.46; 95% confidence interval [CI], 1.16 to 5.21]; I²=0%; p=0.54). Among the 5 observational studies, the absolute rate of DKA associated with SGLT2 inhibitor use ranged from 0.6 to 4.9 per 1,000 person years and a 1.7-fold higher rate of DKA compared with another diabetes medication (RR, 1.74; 95% CI, 1.07 to 2.83; I²=45%; p=0.12).

CONCLUSIONS

In adults with type 2 diabetes, SGLT2 inhibitors were found to increase the risk of DKA in both observational studies and large randomized clinical trials.

100th anniversary of the discovery of insulin perspective: insulin and adipose tissue fatty acid metabolism

Insulin inhibits systemic nonesterified fatty acid (NEFA) flux to a greater degree than glucose or any other metabolite. This remarkable effect is mainly due to insulin-mediated inhibition of intracellular triglyceride (TG) lipolysis in adipose tissues and is essential to prevent diabetic ketoacidosis, but also to limit the potential lipotoxic effects of NEFA in lean tissues that contribute to the development of diabetes complications. Insulin also regulates adipose tissue fatty acid esterification, glycerol and TG synthesis, lipogenesis, and possibly oxidation, contributing to the trapping of dietary fatty acids in the postprandial state. Excess NEFA flux at a given insulin level has been used to define in vivo adipose tissue insulin resistance. Adipose tissue insulin resistance defined in this fashion has been associated with several dysmetabolic features and complications of diabetes, but the mechanistic significance of this concept is not fully understood. This review focusses on the in vivo regulation of adipose tissue fatty acid metabolism by insulin and the mechanistic significance of the current definition of adipose tissue insulin resistance. One hundred years after the discovery of insulin and despite decades of investigations, much is still to be understood about the multifaceted in vivo actions of this hormone on adipose tissue fatty acid metabolism.

Effect of short-term ketogenic diet on end-tidal carbon dioxide

BACKGROUND & AIMS

Previous studies have shown that end-tidal carbon dioxide (EtCO₂) is lower with the presence of supraphysiological ketones as in the case of chronic ketogenic diet (KD) and diabetic ketoacidosis (DKA). This study aimed to determine changes in EtCO₂ upon short term KD.

METHODS

Healthy subjects were screened not to have conditions that exerts abnormal EtCO₂ nor contraindicated for KD. Subjects underwent seven days of KD while the EtCO2 and blood ketone (beta-hydroxybutyrate; β-OHB) parameters were sampled at day zero (t0) and seven (t7) of ketosis respectively. Statistically, the t-test and Pearson's coefficient were conducted to determine the changes and correlation of both parameters.

RESULTS

12 subjects completed the study. The mean score ± standard deviation (SD) for EtCO₂ were 35.08 ± 3.53 and 35.67 ± 3.31 mm Hg for t0 and t7 respectively. The mean score ±SD for β-OHB were 0.07 ± 0.08 and 0.87 ± 0.84 mmol/L for t0 and t7 respectively. There was no significant difference of EtCO₂ between the period of study (p > 0.05) but the β-OHB increased during t7 (p < 0.05). There was also no correlation between the parameters.

CONCLUSIONS

These findings suggest that EtCO₂ may not be utilized to determine short term nutritional ketosis.

Cardioprotective mechanism of SGLT2 inhibitor against myocardial infarction is through reduction of autosis

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce cardiovascular mortality in patients with diabetes mellitus but the protective mechanism remains elusive. Here we demonstrated that the SGLT2 inhibitor, Empagliflozin (EMPA), suppresses cardiomyocytes autosis (autophagic cell death) to confer cardioprotective effects. Using myocardial infarction (MI) mouse models with and without diabetes mellitus, EMPA treatment significantly reduced infarct size, and myocardial fibrosis, thereby leading to improved cardiac function and survival. In the context of ischemia and nutritional glucose deprivation where autosis is already highly stimulated, EMPA directly inhibits the activity of the Na⁺/H⁺ exchanger 1 (NHE1) in the cardiomyocytes to regulate excessive autophagy. Knockdown of NHE1 significantly rescued glucose deprivation-induced autosis. In contrast, overexpression of NHE1 aggravated the cardiomyocytes death in response to starvation, which was effectively rescued by EMPA treatment. Furthermore, in vitro and in vivo analysis of NHE1 and Beclin 1 knockout mice validated that EMPA’s cardioprotective effects are at least in part through downregulation of autophagic flux. These findings provide new insights for drug development, specifically targeting NHE1 and autosis for ventricular remodeling and heart failure after MI in both diabetic and non-diabetic patients.

Assessing the risk of ketoacidosis due to sodium-glucose cotransporter (SGLT)-2 inhibitors in patients with type 1 diabetes: A meta-analysis and meta-regression

BACKGROUND

Sodium-glucose cotransporter-2 (SGLT2) inhibitors (SGLT2i) showed benefits in type 1 diabetes mellitus (T1DM), but the risk of diabetic ketoacidosis (DKA) limits their use. Ability to predict DKA risk and therapeutic responses would enable appropriate patient selection for SGLT2i. We conducted a meta-analysis and meta-regression of randomized controlled trials (RCTs) evaluating SGLT2i in T1DM to assess moderators of the relative risk (RR) of DKA, of glycemic (HbA1c, fasting plasma glucose, continuous glucose monitoring parameters, insulin dose, and insulin sensitivity indices) and non-glycemic (body mass index (BMI), systolic BP, renal function, albuminuria, and diabetic eye disorders) efficacy, and of other safety outcomes (including hypoglycemia, infections, major adverse cardiovascular events, and death).

METHODS AND FINDINGS

We searched MEDLINE, Cochrane Library, EMBASE, ClinicalTrials.gov, Cochrane CENTRAL Register of Controlled Trials, and other electronic sources through August 30, 2020, for RCTs comparing SGLT2i with active comparators or placebo in adult patients with T1DM. Reviewers extracted data for relevant outcomes, performed random effects meta-analyses, subgroup analyses, and multivariable meta-regression. The strength of evidence was summarized with the GRADE approach. Among 9,914 records identified, 18 placebo-controlled RCTs (7,396 participants, 50% males, mean age 42 y (range 23 to 55 y), 5 different SGLT2i evaluated), were included. Main outcome measures were effect sizes and moderators of glycemic and non-glycemic efficacy and of safety outcomes. In a multivariable meta-regression model, baseline BMI (β = 0.439 [95% CI: 0.211, 0.666], p < 0.001) and estimated glucose disposal rate (eGDR) (β = -0.766 [-1.276, -0.256], p = 0.001) were associated with the RR of DKA (RR: 2.81; 95% CI:1.97, 4.01; p < 0.001, R2 = 61%). A model including also treatment-related parameters (insulin dose change-to-baseline insulin sensitivity ratio and volume depletion) explained 86% of variance across studies in the risk of DKA (R2 = 86%). The association of DKA with a BMI >27 kg/m2 and with an eGDR <8.3 mg/kg/min was confirmed also in subgroup analyses. Among efficacy outcomes, the novel findings were a reduction in albuminuria (WMD: -9.91, 95% CI: -16.26, -3.55 mg/g, p = 0.002), and in RR of diabetic eye disorders (RR: 0.27[0.11, 0.67], p = 0.005) associated with SGLT2i. A SGLT2i dose-response gradient was consistently observed for main efficacy outcomes, but not for adverse events (AEs). Overall, predictors of DKA and of other AEs differed substantially from those of glycemic and non-glycemic efficacy. A limitation of our analysis was the relatively short (≤52 weeks) duration of included RCTs. The potential relevance for clinical practice needs also to be confirmed by real-world prospective studies.

CONCLUSIONS

In T1DM, the risk of DKA and main therapeutic responses to SGLT2i are modified by baseline BMI and insulin resistance, by total insulin dose reduction-to-baseline insulin sensitivity ratio, and by volume depletion, which may enable the targeted use of these drugs in patients with the greatest benefit and the lowest risk of DKA.

Molecular Mechanisms of SGLT2 Inhibitor on Cardiorenal Protection

The development of sodium-glucose transporter 2 inhibitor (SGLT2i) broadens the therapeutic strategies in treating diabetes mellitus. By inhibiting sodium and glucose reabsorption from the proximal tubules, the improvement in insulin resistance and natriuresis improved the cardiovascular mortality in diabetes mellitus (DM) patients. It has been known that SGLT2i also provided renoprotection by lowering the intraglomerular hypertension by modulating the pre- and post- glomerular vascular tone. The application of SGLT2i also provided metabolic and hemodynamic benefits in molecular aspects. The recent DAPA-CKD trial and EMPEROR-Reduced trial provided clinical evidence of renal and cardiac protection, even in non-DM patients. Therefore, the aim of the review is to clarify the hemodynamic and metabolic modulation of SGLT2i from the molecular mechanism.

Organ protection by SGLT2 inhibitors: role of metabolic energy and water conservation

Therapeutic inhibition of the sodium-glucose co-transporter 2 (SGLT2) leads to substantial loss of energy (in the form of glucose) and additional solutes (in the form of Na⁺ and its accompanying anions) in urine. However, despite the continuously elevated solute excretion, long-term osmotic diuresis does not occur in humans with SGLT2 inhibition. Rather, patients on SGLT2 inhibitor therapy adjust to the reduction in energy availability and conserve water. The metabolic adaptations that are induced by SGLT2 inhibition are similar to those observed in aestivation - an evolutionarily conserved survival strategy that enables physiological adaptation to energy and water shortage. Aestivators exploit amino acids from muscle to produce glucose and fatty acid fuels. This endogenous energy supply chain is coupled with nitrogen transfer for organic osmolyte production, which allows parallel water conservation. Moreover, this process is often accompanied by a reduction in metabolic rate. By comparing aestivation metabolism with the fuel switches that occur during therapeutic SGLT2 inhibition, we suggest that SGLT2 inhibitors induce aestivation-like metabolic patterns, which may contribute to the improvements in cardiac and renal function observed with this class of therapeutics.

SGLT2 is not expressed in pancreatic α- and β-cells, and its inhibition does not directly affect glucagon and insulin secretion in rodents and humans

Objective

Sodium-glucose cotransporter 2 (SGLT2) inhibitors (SGLT2i), or gliflozins, are anti-diabetic drugs that lower glycemia by promoting glucosuria, but they also stimulate endogenous glucose and ketone body production. The likely causes of these metabolic responses are increased blood glucagon levels, and decreased blood insulin levels, but the mechanisms involved are hotly debated. This study verified whether or not SGLT2i affect glucagon and insulin secretion by a direct action on islet cells in three species, using multiple approaches.

Methods

We tested the in vivo effects of two selective SGLT2i (dapagliflozin, empagliflozin) and a SGLT1/2i (sotagliflozin) on various biological parameters (glucosuria, glycemia, glucagonemia, insulinemia) in mice. mRNA expression of SGLT2 and other glucose transporters was assessed in rat, mouse, and human FACS-purified α- and β-cells, and by analysis of two human islet cell transcriptomic datasets. Immunodetection of SGLT2 in pancreatic tissues was performed with a validated antibody. The effects of dapagliflozin, empagliflozin, and sotagliflozin on glucagon and insulin secretion were assessed using isolated rat, mouse and human islets and the in situ perfused mouse pancreas. Finally, we tested the long-term effect of SGLT2i on glucagon gene expression.

Results

SGLT2 inhibition in mice increased the plasma glucagon/insulin ratio in the fasted state, an effect correlated with a decline in glycemia. Gene expression analyses and immunodetections showed no SGLT2 mRNA or protein expression in rodent and human islet cells, but moderate SGLT1 mRNA expression in human α-cells. However, functional experiments on rat, mouse, and human (29 donors) islets and the in situ perfused mouse pancreas did not identify any direct effect of dapagliflozin, empagliflozin or sotagliflozin on glucagon and insulin secretion. SGLT2i did not affect glucagon gene expression in rat and human islets.

Conclusions

The data indicate that the SGLT2i-induced increase of the plasma glucagon/insulin ratio in vivo does not result from a direct action of the gliflozins on islet cells.

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Gliflozins (SGLT2 and SGLT1/2 inhibitors) increase plasma glucagon/insulin ratio.

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SGLT2 is not expressed in rodent and human pancreatic α- and β-cells.

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SGLT1 is however expressed in human α-cells.

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SGLT2 and SGLT1/2 inhibitors do not directly affect glucagon and insulin secretion.

Case report of superior mesenteric artery syndrome that developed in a lean type 2 diabetes patient and was associated with rapid body weight loss after sodium-glucose cotransporter 2 inhibitor administration

A 58-year-old women who was diagnosed with type 2 diabetes 20 years earlier had been treated with antidiabetic medicines since she was aged 40 years. After sodium-glucose cotransporter 2 inhibitors administration, her bodyweight rapidly decreased from 40 to 30 kg over a period of 3 weeks. She had abdominal symptoms, including nausea, especially after a meal. On admission, physical examinations and laboratory data showed euglycemic ketoacidosis, dehydration and low insulin secretion levels. Additionally, abdominal contrast computed tomography showed the finding of superior mesenteric artery syndrome. This case urges caution, including rapid excessive bodyweight loss and euglycemic ketoacidosis, on the use of sodium-glucose cotransporter 2 for lean diabetes patients.

Early detection of euglycemic ketoacidosis during thoracic surgery associated with empagliflozin in a patient with type 2 diabetes: A case report

We report the first case of intraoperatively detected euglycemic diabetic ketoacidosis (DKA) associated with sodium–glucose cotransporter 2 inhibitors during thoracic surgery. A 59‐year‐old man had a 12‐year history of type 2 diabetes mellitus treated with insulin and empagliflozin. The patient developed bacterial empyema and was initiated with antibiotics at a local hospital. Owing to the persistence of his symptoms, he was transferred to our hospital after the medication of empagliflozin the day before surgery. After overnight fasting, the patient underwent thoracoscopic debridement and intrathoracic lavage surgery. During this surgery, he was noted to have euglycemic ketosis and acidosis, and diagnosed as euglycemic DKA. Immediately after the consultation in our department, the patient underwent treatment for DKA. He awoke from anesthesia normally and showed no symptoms of DKA. DKA gradually resolved over the next 24 h. Early identification and management are critical for rapid recovery from perioperative euglycemic DKA associated with sodium–glucose cotransporter 2 inhibitors, especially during thoracic surgery.

Sodium-glucose cotransporter-2 inhibitors: Understanding the mechanisms for therapeutic promise and persisting risks

In a healthy person, the kidney filters nearly 200 g of glucose per day, almost all of which is reabsorbed. The primary transporter responsible for renal glucose reabsorption is sodium-glucose cotransporter-2 (SGLT2). Based on the impact of SGLT2 to prevent renal glucose wasting, SGLT2 inhibitors have been developed to treat diabetes and are the newest class of glucose-lowering agents approved in the United States. By inhibiting glucose reabsorption in the proximal tubule, these agents promote glycosuria, thereby reducing blood glucose concentrations and often resulting in modest weight loss. Recent work in humans and rodents has demonstrated that the clinical utility of these agents may not be limited to diabetes management: SGLT2 inhibitors have also shown therapeutic promise in improving outcomes in heart failure, atrial fibrillation, and, in preclinical studies, certain cancers. Unfortunately, these benefits are not without risk: SGLT2 inhibitors predispose to euglycemic ketoacidosis in those with type 2 diabetes and, largely for this reason, are not approved to treat type 1 diabetes. The mechanism for each of the beneficial and harmful effects of SGLT2 inhibitors-with the exception of their effect to lower plasma glucose concentrations-is an area of active investigation. In this review, we discuss the mechanisms by which these drugs cause euglycemic ketoacidosis and hyperglucagonemia and stimulate hepatic gluconeogenesis as well as their beneficial effects in cardiovascular disease and cancer. In so doing, we aim to highlight the crucial role for selecting patients for SGLT2 inhibitor therapy and highlight several crucial questions that remain unanswered.

Diabetes, and its treatment, as an effector of autonomic nervous system circuits and its functions

Diabetes increases the risk of cardiovascular complications, including heart failure, hypertension, and stroke. There is a strong involvement of autonomic dysfunction in individuals with diabetes that exhibit clinical manifestations of cardiovascular diseases (CVD). Still, the mechanisms by which diabetes and its treatments alter autonomic function and subsequently affect cardiovascular complications remain elusive. For this reason, understanding the brainstem circuits involved in sensing metabolic state(s) and enacting autonomic control of the cardiovascular system are important to develop more comprehensive therapies for individuals with diabetes at increased risk for CVD. We review how autonomic nervous system circuits change during these disease states and discuss their potential role in current pharmacotherapies that target diabetic states. Overall, this review proposes that the brainstem circuits provide an integrative sensorimotor network capable of responding to metabolic cues to regulate cardiovascular function and this network is modified by, and in turn affects, diabetes-induced CVD and its treatment.

Severe euglycemic diabetic ketoacidosis of multifactorial etiology in a type 2 diabetic patient treated with empagliflozin: case report and literature review

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT-2) inhibitors are a relatively novel class of oral medications for the treatment of Type 2 DM with a generally acceptable safety profile. However, these agents have been associated with rare events of a serious and potentially life-threatening complication named euglycemic diabetic ketoacidosis (euDKA). euDKA is not identical with the typical diabetic ketoacidosis, as it often presents with serious metabolic acidosis but only mild to moderate glucose and anion gap elevation.

CASE PRESENTATION

We report a case of a 51-year old female with Type 2 DM treated with an SGLT-2 inhibitor, developing severe metabolic acidosis with only mild blood glucose elevation after a routine surgery. A careful evaluation of involved factors led to the diagnosis of euDKA, followed by cautious application of simple therapeutic measures that resulted in complete restoration of acidosis and glycemic control in less than 48-h.

CONCLUSIONS

Euglycemic ketoacidosis is a rare but rather serious complication of SGLT-2 inhibitors use, often with a multifactorial etiology. Its atypical presentation requires a high level of awareness by physicians as early recognition of this complication can quickly and safely restore acid-base balance.

Euglycaemic diabetic ketoacidosis as a complication of SGLT-2 inhibitors: epidemiology, pathophysiology, and treatment

INTRODUCTION

Sodium-glucose co-transporters 2 (SGLT-2) inhibitors are a relatively novel class of oral medications for the treatment of Type 2 Diabetes Mellitus, which lower plasma glucose by inhibiting glucose reabsorption in the proximal renal tubule. Apart from their hypoglycemic action, recent data suggest these agents have additional major cardioprotective and nephroprotective properties.

AREAS COVERED

This review summarizes the existing data on epidemiology, pathophysiology, and treatment of euglycaemic ketoacidosis (euDKA) as a complication of SGLT-2 inhibitor use.

EXPERT OPINION

Although SGLT-2 inhibitors have a relatively good adverse event profile, they have been associated with the serious and potentially life-threatening metabolic complication of euDKA. Data from major outcome trials suggest that the rate of DKA is quite low. However, the rate of DKA could be generally underestimated in clinical trials due to the atypical presentation of ketoacidosis, and even more so in real-life conditions. Management of this serious metabolic complication requires a proper understanding of its pathophysiology as well as increased awareness and early recognition of the potential risk factors involved. Following this, the institution of an array of simple supportive measures, could safely restore normal acid-base balance in most patients.

The Limited Role of Glucagon for Ketogenesis During Fasting or in Response to SGLT2 Inhibition

Glucagon is classically described as a counterregulatory hormone that plays an essential role in the protection against hypoglycemia. In addition to its role in the regulation of glucose metabolism, glucagon has been described to promote ketosis in the fasted state. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are a new class of glucose-lowering drugs that act primarily in the kidney, but some reports have described direct effects of SGLT2i on α-cells to stimulate glucagon secretion. Interestingly, SGLT2 inhibition also results in increased endogenous glucose production and ketone production, features common to glucagon action. Here, we directly test the ketogenic role of glucagon in mice, demonstrating that neither fasting- nor SGLT2i-induced ketosis is altered by interruption of glucagon signaling. Moreover, any effect of glucagon to stimulate ketogenesis is severely limited by its insulinotropic actions. Collectively, our data suggest that fasting-associated ketosis and the ketogenic effects of SGLT2 inhibitors occur almost entirely independent of glucagon.