The impact of increased hepatic glucose production caused by empagliflozin on plasma glucose concentration in individuals with type 2 diabetes and nondiabetic individuals.

AIM: To examine the impact of increased hepatic glucose production (HGP) on the decrease in plasma glucose concentration caused by empagliflozin in individuals living with diabetes and in nondiabetic individuals. METHODS: A total of 36 individuals living with diabetes and 34 nondiabetic individuals were randomized to receive, in double-blind fashion, empagliflozin or matching placebo in a 2:1 treatment ratio. Following an overnight fast, HGP was measured with 3-3 H-glucose infusion before, at the start of, and 3 months after therapy with empagliflozin. RESULTS: On Day 1 of empagliflozin administration, the increase in urinary glucose excretion (UGE) in individuals with normal glucose tolerance was smaller than in those with impaired glucose tolerance and those living with diabetes, and was accompanied by an increase in HGP in all three groups. The amount of glucose returned to the systemic circulation as a result of the increase in HGP was smaller than that excreted by the kidney during the first 3 h after empagliflozin administration, resulting in a decrease in fasting plasma glucose (FPG) concentration. After 3 h, the increase in HGP was in excess of UGE, leading to a small increase in plasma glucose concentration, which reached a new steady state. After 12 weeks, the amount of glucose returned to the circulation due to the empagliflozin-induced increase in HGP was comparable with that excreted by the kidney in all three groups. CONCLUSION: The balance between UGE and increase in HGP immediately after sodium-glucose cotransporter-2 (SGLT2) inhibition determined the magnitude of decrease in FPG and the new steady state which was achieved. After 12 weeks, the increase in HGP caused by empagliflozin closely matched the amount of glucose excreted by the kidneys; thus, FPG level remained stable despite the continuous urinary excretion of glucose caused by SGLT2 inhibition.

Real-world effectiveness of sodium-glucose cotransporter-2 inhibitors on the progression of chronic kidney disease in patients without diabetes, with and without albuminuria.

AIM: To examine the renal effects of sodium-glucose cotransporter-2 (SGLT2) inhibition among non-diabetic individuals with chronic kidney disease (CKD) in a real-world setting. METHODS: We collected de-identified data on adults without diabetes and with an estimated glomerular filtration rate (eGFR) of 25-60 mL/min/1.73 m2, who initiated the SGLT2 inhibitors dapagliflozin or empagliflozin between September 2020 and November 2022 at Maccabi Healthcare Services, an Israeli health maintenance organization. We assessed the effects of SGLT2 inhibitors on renal function (changes in eGFR slope/time). Index date was defined as the date of the first dispensing of SGLT2 inhibitors. Annual baseline slope was calculated using all eGFR measurements during the 2 years prior to index date (median = 7 measurements), while annual follow-up slope was calculated from all evaluations during 90-900 days post index date, along with baseline measurement at index date (median = 6 measurements). Paired t tests were used to compare differences between baseline and follow-up annual slopes. RESULTS: Of a total of 354 participants with CKD, without diabetes, who received SGLT2 inhibitors and were followed for a median of 527 days, the mean age was 72.8 ± 11.8 years, 26% were female, and 91% used renin-angiotensin system blockade. The mean eGFR was 45.4 ± 9.5 mL/min/1.73 m2. The mean body mass index was 29.1 ± 5.4 kg/m2. During the year before index date, 146 participants (41%) had a urinary albumin to creatinine ratio (UACR) <30 mg/g, 81 (23%) had a UACR of 30-300 mg/g, 74 (21%) had a UACR >300 mg/g, and 53 (15%) had no UACR evaluation. The mean eGFR slope over time was -5.6 ± 7.7 mL/min/1.73 m2 per year at baseline, which improved to -1.7 ± 6.8 mL/min/1.73 m2 per year after SGLT2 inhibitor administration (p <0.001). This effect was independent of UACR. CONCLUSION: In a real-world study of primarily older non-diabetic adults with CKD, SGLT2 inhibition was associated with a slower rate of kidney function decline, regardless of baseline UACR level.

Plasma insulin is required for the increase in plasma angiopoietin-like protein 8 in response to nutrient ingestion.

BACKGROUND: Plasma levels of angiopoietin-like protein 8 (ANGPTL8) are regulated by feeding and they increase following glucose ingestion. Because both plasma glucose and insulin increase following food ingestion, we aimed to determine whether the increase in plasma insulin and glucose or both are responsible for the increase in ANGPTL8 levels. METHODS: ANGPTL8 levels were measured in 30 subjects, 14 with impaired fasting glucose (IFG), and 16 with normal fasting glucose (NFG); the subjects received 75g glucose oral Glucose tolerance test (OGTT), multistep euglycaemic hyperinsulinemic clamp and hyperglycaemic clamp with pancreatic clamp. RESULTS: Subjects with IFG had significantly higher ANGPTL8 than NGT subjects during the fasting state (p < 0.05). During the OGTT, plasma ANGPTL8 concentration increased by 62% above the fasting level (p < 0.0001), and the increase above fasting in ANGPTL8 levels was similar in NFG and IFG individuals. During the multistep insulin clamp, there was a dose-dependent increase in plasma ANGPTL8 concentration. During the 2-step hyperglycaemic clamp, the rise in plasma glucose concentration failed to cause any change in the plasma ANGPTL8 concentration from baseline. CONCLUSIONS: In response to nutrient ingestion, ANGPTL8 level increased due to increased plasma insulin concentration, not to the rise in plasma glucose. The incremental increase above baseline in plasma ANGLPTL8 during OGTT was comparable between people with normal glucose tolerance and IFG.

Pioglitazone reduces epicardial fat and improves diastolic function in patients with type 2 diabetes.

AIMS: To examine the effect of pioglitazone on epicardial (EAT) and paracardial adipose tissue (PAT) and measures of diastolic function and insulin sensitivity in patients with type 2 diabetes mellitus (T2DM). METHODS: Twelve patients with T2DM without clinically manifest cardiovascular disease and 12 subjects with normal glucose tolerance (NGT) underwent cardiac magnetic resonance imaging to quantitate EAT and PAT and diastolic function before and after pioglitazone treatment for 24 weeks. Whole-body insulin sensitivity was measured with a euglycaemic insulin clamp and the Matsuda Index (oral glucose tolerance test). RESULTS: Pioglitazone reduced glycated haemoglobin by 0.9% (P < 0.05), increased HDL cholesterol by 7% (P < 0.05), reduced triacylglycerol by 42% (P < 0.01) and increased whole-body insulin-stimulated glucose uptake by 71% (P < 0.01) and Matsuda Index by 100% (P < 0.01). In patients with T2DM, EAT (P < 0.01) and PAT (P < 0.01) areas were greater compared with subjects with NGT, and decreased by 9% (P = 0.03) and 9% (P = 0.09), respectively, after pioglitazone treatment. Transmitral E/A flow rate and peak left ventricular flow rate (PLVFR) were reduced in T2DM versus NGT (P < 0.01) and increased following pioglitazone treatment (P < 0.01-0.05). At baseline normalized PLVFR inversely correlated with EAT (r = -0.45, P = 0.03) but not PAT (r = -0.29, P = 0.16). E/A was significantly and inversely correlated with EAT (r = -0.55, P = 0.006) and PAT (r = -0.40, P = 0.05). EAT and PAT were inversely correlated with whole-body insulin-stimulated glucose uptake (r = -0.68, P < 0.001) and with Matsuda Index (r = 0.99, P < 0.002). CONCLUSION: Pioglitazone reduced EAT and PAT areas and improved left ventricular (LV) diastolic function in T2DM. EAT and PAT are inversely correlated (PAT less strongly) with LV diastolic function and both EAT and PAT are inversely correlated with measures of insulin sensitivity.

A randomised crossover trial: Exploring the dose-response effect of carbohydrate restriction on glycaemia in people with well-controlled type 2 diabetes.

BACKGROUND: Trials investigating the role of carbohydrate restriction in the management of glycaemia in type 2 diabetes (T2D) have been confounded by multiple factors, including degree of calorie restriction and dietary protein content, as well as by no clear definition of a low-carbohydrate diet. The present study aimed to provide insight into the relationship between carbohydrate restriction and glycaemia by testing the effect of varying doses of carbohydrate on continuous glucose concentrations within a range of intakes defined as low-carbohydrate at the same time as controlling for confounding factors. METHODS: This was a randomised crossover trial in participants with T2D (HbA1c: 6.6 ± 0.6%, 49 ± 0.9 mmol mol-1 ) testing five different 6-day eucaloric dietary treatments with varying carbohydrate content (10%, 15%, 20%, 25%, and 30% kcal). Diets exchanged %kcal from carbohydrate with fat, keeping protein constant at 15% kcal. Daily self-weighing was employed to ensure weight stability throughout each treatment arm. Between dietary treatments, participants underwent a washout period of at least 7 days and were advised to maintain their habitual diet. Glycaemic control was assessed using a continuous glucose monitoring device. RESULTS: Twelve participants completed the study. There were no differences in 24-h and post-prandial sensor glucose concentrations between the 30 and 10%kcal doses (7.4 ± 1.1 mmol L-1 vs. 7.6 ± 1.3 mmol L-1 [p = 0.28] and 8.1 ± 1.5 mmol L-1 vs. 8.5 ± 1.4 mmol L-1 [p = 0.28], respectively). In our exploratory analyses, we did not find any dose-response relationship between carbohydrate intake and glycaemia. A small amount of weight loss occurred in each treatment arm (range: 0.4-1.1 kg over the 6 days) but adjusting for these differences did not influence the primary or secondary outcomes. CONCLUSIONS: Modest changes in dietary carbohydrate content in the absence of weight loss at the same time as keeping dietary protein intake constant do not appear to influence glucose concentrations in people with well-controlled T2D. SUMMARY: This study randomised people with T2D to receive five different doses of carbohydrate from 10% to 30% of calories in random order to see what effect it had on their blood glucose.

FGF21 contributes to metabolic improvements elicited by combination therapy with exenatide and pioglitazone in patients with type 2 diabetes.

Fibroblast growth factor 21 (FGF21) is increased acutely by carbohydrate ingestion and is elevated in patients with type 2 diabetes (T2D). However, the physiological significance of increased FGF21 in humans remains largely unknown. We examined whether FGF21 contributed to the metabolic improvements observed following treatment of patients with T2D with either triple (metformin/pioglitazone/exenatide) or conventional (metformin/insulin/glipizide) therapy for 3 yr. Forty-six patients with T2D were randomized to receive either triple or conventional therapy to maintain HbA1c < 6.5%. A 2-h 75-g oral glucose tolerance test (OGTT) was performed at baseline and following 3 years of treatment to assess glucose tolerance, insulin sensitivity, and ß-cell function. Plasma total and bioactive FGF21 levels were quantitated before and during the OGTT at both visits. Patients in both treatment arms experienced significant improvements in glucose control, but insulin sensitivity and ß-cell function were markedly increased after triple therapy. At baseline, FGF21 levels were regulated acutely during the OGTT in both groups. After treatment, fasting total and bioactive FGF21 levels were significantly reduced in patients receiving triple therapy, but there was a relative increase in the proportion of bioactive FGF21 compared with that observed in conventionally treated subjects. Relative to baseline studies, triple therapy treatment also significantly modified FGF21 levels in response to a glucose load. These changes in circulating FGF21 were correlated with markers of improved glucose control and insulin sensitivity. Alterations in the plasma FGF21 profile may contribute to the beneficial metabolic effects of pioglitazone and exenatide in human patients with T2D.NEW & NOTEWORTHY In patients with T2D treated with a combination of metformin/pioglitazone/exenatide (triple therapy), we observed reduced total and bioactive plasma FGF21 levels and a relative increase in the proportion of circulating bioactive FGF21 compared with that in patients treated with metformin and sequential addition of glipizide and basal insulin glargine (conventional therapy). These data suggest that FGF21 may contribute, at least in part, to the glycemic benefits observed following combination therapy in patients with T2D.

Type 2 diabetes subgroups and response to glucose-lowering therapy: Results from the EDICT and Qatar studies.

AIM: To examine the efficacy of glucose-lowering medications in subgroups of patients with type 2 diabetes mellitus (T2DM). RESEARCH DESIGN AND METHODS: Cluster analysis was performed in participants in the Efficacy and Durability of Initial Combination Therapy for Type 2 Diabetes (EDICT) study and the Qatar study using age, body mass index (BMI), glycated haemoglobin (HbA1c), and homeostatic model assessment of insulin resistance (HOMA-IR) and beta-cell function (HOMA-ß). Participants also underwent an oral glucose tolerance test with measurement of plasma glucose, insulin and C-peptide concentrations to derive independent measures of insulin secretion and insulin sensitivity. The response to glucose-lowering therapies (change in HbA1c) was measured in each participant cluster for 3 years. RESULTS: Three distinct and comparable clusters/groups of T2DM patients were identified in both the EDICT and Qatar studies. Participants in Group 1 had the highest HbA1c and manifested severe insulin deficiency. Participants in Group 3 had comparable insulin sensitivity to those in Group 1 but better beta-cell function and better glucose control. Participants in Group 2 had the highest BMI with severe insulin resistance accompanied by marked hyperinsulinaemia, which was primarily attributable to decreased insulin clearance. Unexpectedly, participants in Group 1 had better response to combination therapy with pioglitazone plus exenatide than with insulin therapy or metformin sequentially followed by glipizide and basal insulin, while participants in Group 2 responded equally well to both therapies despite very severe insulin resistance. CONCLUSION: Distinct metabolic phenotypes characterize different T2DM clusters and differential responses to glucose-lowering therapies. Participants with severe insulin deficiency respond better to agents that preserve beta-cell function, while, surprisingly, patients with severe insulin resistance did not respond favourably to insulin sensitizers.

Efficacy of lower doses of pioglitazone after stroke or transient ischaemic attack in patients with insulin resistance.

AIMS: Pioglitazone is a potent insulin-sensitizing drug with anti-atherosclerotic properties, but adverse effects have limited its use. We assessed the benefits and risks of lower versus higher doses of pioglitazone taken by participants in the Insulin Resistance Intervention in Stroke Trial. MATERIALS AND METHODS: Efficacy [myocardial infarction (MI) or recurrent stroke] new-onset diabetes) and adverse outcomes (oedema, weight gain, heart failure and bone fracture) were examined for subjects assigned to pioglitazone or placebo within strata defined by mode dose of study drug taken (i.e. the dose taken on most days in the study). RESULTS: Among the 1938 patients randomized to pioglitazone, the mode dose was <15 mg/day in 546 participants, 15 mg/day in 128, 30 mg/day in 89, and 45 mg/day in 1175. There was no significant effect on stroke/MI or new-onset diabetes with <15 mg/day. For 15 mg/30 mg/day pooled, the adjusted hazard ratios (95% CI) for stroke/MI were 0.48 (0.30, 0.76; p = .002) and 0.74 (0.69, 0.94) for 45 mg/day. For new-onset diabetes, the adjusted hazard ratios were 0.34 (0.15, 0.81; p = .001) and 0.31 (0.59, 0.94; p = .001) respectively. For oedema, weight gain and heart failure, the risk estimates for pioglitazone were lower for subjects taking <45 mg daily. For fractures, the increased risk with pioglitazone was similar across all dose strata. CONCLUSIONS: Lower doses of pioglitazone appear to confer much of the benefit with less adverse effects than the full dose. Further study is needed to confirm these findings so that clinicians may optimize dosing of this secondary prevention strategy in patients with stroke.

Combination therapy with pioglitazone/exenatide/metformin reduces the prevalence of hepatic fibrosis and steatosis: The efficacy and durability of initial combination therapy for type 2 diabetes (EDICT).

AIM: To compare the efficacy of triple therapy (metformin/exenatide/pioglitazone) versus stepwise conventional therapy (metformin → glipizide → glargine insulin) on liver fat content and hepatic fibrosis in newly diagnosed, drug-naïve patients with type 2 diabetes. METHODS: Sixty-eight patients completed the 6-year follow-up and had an end-of-study (EOS) FibroScan to provide measures of steatosis (controlled attenuation parameter [CAP] in dB/m) and fibrosis (liver stiffness measurement [LSM] in kPa); 59 had magnetic resonance imaging-proton density fat fraction (MRI-PDFF) to measure liver fat. RESULTS: At EOS, HbA1c was 6.8% and 6.0% in triple and conventional therapy groups, respectively (P = .0006). Twenty-seven of 39 subjects (69%) receiving conventional therapy had grade 2/3 steatosis (CAP, FibroScan) versus nine of 29 (31%) in triple therapy (P = .0003). Ten of 39 (26%) subjects receiving conventional therapy had stage 3/4 fibrosis (LSM) versus two of 29 (7%) in triple therapy (P = .04). Conventional therapy subjects had more liver fat (MRI-PDFF) than triple therapy (12.9% vs. 8.8%, P = .03). The severity of steatosis (CAP) (r = 0.42, P < .001) and fibrosis (LSM) (r = -0.48, P < .001) correlated inversely with the Matsuda Index of insulin sensitivity, but not with percentage body fat. Aspartate aminotransferase (AST) to Platelet Ratio Index (APRI), non-alcoholic fatty liver disease fibrosis score (NFS), plasma AST, and alanine aminotransferase (ALT) all decreased significantly with triple therapy, but only the decrease in plasma AST and ALT correlated with the severity of steatosis and fibrosis at EOS. CONCLUSIONS: At EOS, subjects with type 2 diabetes treated with triple therapy had less hepatic steatosis and fibrosis versus conventional therapy; the severity of hepatic steatosis and fibrosis were both strongly and inversely correlated with insulin resistance; and changes in liver fibrosis scores (APRI, NFS, Fibrosis-4, and AST/ALT ratio) have limited value in predicting response to therapy.

Insulin secretion is a strong predictor for need of insulin therapy in patients with new-onset diabetes and HbA1c of more than 10%: A post hoc analysis of the EDICT study.

AIM: To identify predictors of response to glucose-lowering therapy in patients with new-onset diabetes and very high HbA1c (>10%). METHODS: The study included EDICT participants with an initial HbA1c of more than 10% (N = 104). All subjects received a 75-g oral glucose tolerance test (OGTT) before initiation of therapy, and then were randomized to receive: (a) initial triple therapy with metformin, pioglitazone and exenatide versus (b) stepwise conventional therapy with metformin followed by glipizide and then glargine insulin to reduce HbA1c to less than 6.5%. Insulin secretion and insulin resistance were calculated with OGTT-derived indices. RESULTS: Sixty-one per cent of participants in the conventional therapy group achieved HbA1c of less than 6.5% at 6 months without need of insulin therapy compared with 78% in the triple therapy group (P = NS). Insulin secretion at baseline was the strongest predictor of subjects who did not require insulin therapy; a cut point of CPEP120 /CPEP0 -the ratio between plasma C-peptide concentration at 120 minutes during the OGTT and fasting plasma C-peptide concentration-of more than 1.7 predicted subjects who achieved the treatment target without insulin, irrespective of the fasting plasma glucose (FPG) concentration and whether or not they were started on conventional or triple therapy. Subjects with a CPEP120 /CPEP0 of less than 1.7 plus FPG of 269 mg/dL or less (≤14.9 mmoL/L) also achieved the treatment goal with triple therapy. CONCLUSION: Insulin secretion in response to a 75-g OGTT predicts the need for insulin therapy at the time of type 2 diabetes (T2D) diagnosis. A cut point of 1.7 of CPEP120 /CPEP0 provides a useful clinical tool to individualize glucose-lowering therapy in patients with new-onset T2D and HbA1c of more than 10%.

Sport participation and related head injuries following craniosynostosis correction: a survey study.

OBJECTIVE: Craniosynostosis (CS) affects about 1 in 2500 infants and is predominantly treated by surgical intervention in infancy. Later in childhood, many of these children wish to participate in sports. However, the safety of participation is largely anecdotal and based on surgeon experience. The objective of this survey study was to describe sport participation and sport-related head injury in CS patients. METHODS: A 16-question survey related to child/parent demographics, CS surgery history, sport history, and sport-induced head injury history was made available to patients/parents in the United States through a series of synostosis organization listservs, as well as synostosis-focused Facebook groups, between October 2019 and June 2020. Sports were categorized based on the American Academy of Pediatrics groupings. Pearson's chi-square test, Fisher's exact test, and the independent-samples t-test were used in the analysis. RESULTS: Overall, 187 CS patients were described as 63% male, 89% White, and 88% non-Hispanic, and 89% underwent surgery at 1 year or younger. The majority (74%) had participated in sports starting at an average age of 5 years (SD 2.2). Of those participating in sports, contact/collision sport participation was most common (77%), and 71% participated in multiple sports. Those that played sports were less frequently Hispanic (2.2% vs 22.9%, p < 0.001) and more frequently had undergone a second surgery (44% vs 25%, p = 0.021). Only 9 of 139 (6.5%) sport-participating CS patients suffered head injuries; 6 (67%) were concussions and the remaining 3 were nondescript but did not mention any surgical needs. CONCLUSIONS: In this nationwide survey of postsurgical CS patients and parents, sport participation was exceedingly common, with contact sports being the most common sport category. Few head injuries (mostly concussions) were reported as related to sport participation. Although this is a selective sample of CS patients, the initial data suggest that sport participation, even in contact sports, and typically beginning a few years after CS correction, is safe and commonplace.

Sodium-Glucose Cotransporter 2 Inhibitors and the Kidney.

Diabetic kidney disease (DKD) accounts for about half of individuals entering end-stage renal disease programs. Patients with DKD frequently have associated microvascular complications and are at very high risk for developing macrovascular complications. Comprehensive treatment involves slowing or preventing the decline in glomerular filtration rate (GFR) and preventing macrovascular and further microvascular complications. Maintaining an A1C <6.5% represents primary prevention; in established DKD, tight blood pressure control is essential. ACE inhibitors/angiotensin receptor blockers (ARBs) and sodium-glucose cotransporter 2 (SGLT2) inhibitors can be used in combination to slow the rate of decline in GFR. This article reviews the general approach to DKD treatment and summarizes renal outcomes in four cardiovascular outcomes trials of SGLT2 inhibitors. Together, these trials provide conclusive evidence that SGLT2 inhibitors, added to an ACE inhibitor or ARB, slow the progression of DKD.

Crosstalk between Sodium-Glucose Cotransporter Inhibitors and Sodium-Hydrogen Exchanger 1 and 3 in Cardiometabolic Diseases.

Abnormality in glucose homeostasis due to hyperglycemia or insulin resistance is the hallmark of type 2 diabetes mellitus (T2DM). These metabolic abnormalities in T2DM lead to cellular dysfunction and the development of diabetic cardiomyopathy leading to heart failure. New antihyperglycemic agents including glucagon-like peptide-1 receptor agonists and the sodium-glucose cotransporter-2 inhibitors (SGLT2i) have been shown to attenuate endothelial dysfunction at the cellular level. In addition, they improved cardiovascular safety by exhibiting cardioprotective effects. The mechanism by which these drugs exert their cardioprotective effects is unknown, although recent studies have shown that cardiovascular homeostasis occurs through the interplay of the sodium-hydrogen exchangers (NHE), specifically NHE1 and NHE3, with SGLT2i. Another theoretical explanation for the cardioprotective effects of SGLT2i is through natriuresis by the kidney. This theory highlights the possible involvement of renal NHE transporters in the management of heart failure. This review outlines the possible mechanisms responsible for causing diabetic cardiomyopathy and discusses the interaction between NHE and SGLT2i in cardiovascular diseases.

Increase in endogenous glucose production with SGLT2 inhibition is attenuated in individuals who underwent kidney transplantation and bilateral native nephrectomy.

AIMS/HYPOTHESIS: The glucosuria induced by sodium-glucose cotransporter 2 (SGLT2) inhibition stimulates endogenous (hepatic) glucose production (EGP), blunting the decline in HbA1c. We hypothesised that, in response to glucosuria, a renal signal is generated and stimulates EGP. To examine the effect of acute administration of SGLT2 inhibitors on EGP, we studied non-diabetic individuals who had undergone renal transplant with and without removal of native kidneys. METHODS: This was a parallel, randomised, double-blind, placebo-controlled, single-centre study, designed to evaluate the effect of a single dose of dapagliflozin or placebo on EGP determined by stable-tracer technique. We recruited non-diabetic individuals who were 30-65 years old, with a BMI of 25-35 kg/m2 and stable body weight (±2 kg) over the preceding 3 months, and HbA1c <42 mmol/mol (6.0%). Participants had undergone renal transplant with and without removal of native kidneys and were on a stable dose of immunosuppressive medications. Participants received a single dose of dapagliflozin 10 mg or placebo on two separate days, at a 5- to 14-day interval, according to randomisation performed by our hospital pharmacy, which provided dapagliflozin and matching placebo, packaged in bulk bottles that were sequentially numbered. Both participants and investigators were blinded to group assignment. RESULTS: Twenty non-diabetic renal transplant patients (ten with residual native kidneys, ten with bilateral nephrectomy) participated in the study. Dapagliflozin induced greater glucosuria in individuals with residual native kidneys vs nephrectomised individuals (8.6 ± 1.1 vs 5.5 ± 0.5 g/6 h; p = 0.02; data not shown). During the 6 h study period, plasma glucose decreased only slightly and similarly in both groups, with no difference compared with placebo (data not shown). Following administration of placebo, there was a progressive time-related decline in EGP that was similar in both nephrectomised individuals and individuals with residual native kidneys. Following dapagliflozin administration, EGP declined in both groups, but the differences between the decrement in EGP with dapagliflozin and placebo in the group with bilateral nephrectomy (Δ = 1.11 ± 0.72 µmol min-1 kg-1) was significantly lower (p = 0.03) than in the residual native kidney group (Δ = 2.56 ± 0.33 µmol min-1 kg-1). In the population treated with dapagliflozin, urinary glucose excretion was correlated with EGP (r = 0.34, p < 0.05). Plasma insulin, C-peptide, glucagon, prehepatic insulin:glucagon ratio, lactate, alanine and pyruvate concentrations were similar following placebo and dapagliflozin treatment. ß-Hydroxybutyrate increased with dapagliflozin treatment in the residual native kidney group, while a small increase was observed only at 360 min in the nephrectomy group. Plasma adrenaline (epinephrine) did not change after dapagliflozin and placebo treatment in either group. Following dapagliflozin administration, plasma noradrenaline (norepinephrine) increased slightly in the residual native kidney group and decreased in the nephrectomy group. CONCLUSIONS/INTERPRETATION: In nephrectomised individuals, the hepatic compensatory response to acute SGLT2 inhibitor-induced glucosuria was attenuated, as compared with individuals with residual native kidneys, suggesting that SGLT2 inhibitor-mediated stimulation of hepatic glucose production via efferent renal nerves occurs in an attempt to compensate for the urinary glucose loss (i.e. a renal-hepatic axis). TRIAL REGISTRATION: ClinicalTrials.gov NCT03168295 FUNDING: This protocol was supported by Qatar National Research Fund (QNRF) Award No. NPRP 8-311-3-062 and NIH grant DK024092-38. Graphical abstract.

Regulation of ANGPTL8 in liver and adipose tissue by nutritional and hormonal signals and its effect on glucose homeostasis in mice.

The angiopoietin-like protein (ANGPTL) family represents a promising therapeutic target for dyslipidemia, which is a feature of obesity and type 2 diabetes (T2DM). The aim of the present study was to determine the metabolic role of ANGPTL8 and to investigate its nutritional, hormonal, and molecular regulation in key metabolic tissues. The regulation of Angptl8 gene expression by insulin and glucose was quantified using a combination of in vivo insulin clamp experiments in mice and in vitro experiments in primary and cultured hepatocytes and adipocytes. The role of AMPK signaling was examined, and the transcriptional control of Angptl8 was determined using bioinformatic and luciferase reporter approaches. The metabolism of Angptl8 knockout mice (ANGPTL8-/-) was examined following chow and high-fat diets (HFD). Insulin acutely increased Angptl8 expression in liver and adipose tissue, which involved the CCAAT/enhancer-binding protein (C/EBPß) transcription factor. In insulin clamp experiments, glucose further enhanced Angptl8 expression in the presence of insulin in adipose tissue. The activation of AMPK signaling antagonized the effect of insulin on Angptl8 expression in hepatocytes and adipocytes. The ANGPTL8-/- mice had improved glucose tolerance and displayed reduced fed and fasted plasma triglycerides. However, there was no change in body weight or steatosis in ANGPTL8-/- mice after the HFD. These data show that ANGPTL8 plays important metabolic roles in mice that extend beyond triglyceride metabolism. The finding that insulin, glucose, and AMPK signaling regulate Angptl8 expression may provide important clues about the distinct function of ANGPTL8 in these tissues.

Combination therapy with pioglitazone/exenatide improves beta-cell function and produces superior glycaemic control compared with basal/bolus insulin in poorly controlled type 2 diabetes: A 3-year follow-up of the Qatar study.

AIM: To examine the long-term efficacy of thiazolidinedione plus a glucagon-like peptide-1 receptor agonist versus basal-bolus insulin on glycaemic control and beta-cell function in patients with poorly controlled type 2 diabetes (T2D) on metformin plus sulphonylurea. MATERIALS AND METHODS: Three hundred and thirty-one patients with poorly controlled T2D were recruited over 3 years and were followed for an additional year. Subjects received a 75 g oral glucose tolerance test (OGTT) at baseline and at study end. After completing the baseline OGTT, subjects were randomized to receive either pioglitazone plus weekly exenatide (combination therapy) or basal/bolus insulin (insulin therapy) to maintain an HbA1c of less than 7.0%. The primary outcome of the study was the difference in HbA1c at study end between the two treatment groups. RESULTS: Both therapies caused a robust decrease in HbA1c. However, combination therapy caused a greater decrement (-1.1%, P < .0001) than insulin therapy, and more subjects in the combination therapy group (86%) achieved the American Diabetes Association goal of glycaemic control (HbA1c < 7.0%) than those in the insulin therapy group (44%) (P < .0001). Both therapies improved insulin secretion. However, the improvement in insulin secretion with combination therapy was 2.5-fold greater (P < .001) than with insulin therapy (50%). Insulin therapy caused more weight gain and hypoglycaemia. CONCLUSION: Both combination therapy and insulin therapy effectively reduced HbA1c in poorly controlled T2D on multiple oral agents. However, combination therapy produced a greater improvement in insulin secretion and decrease in HbA1c with a lower risk of hypoglycaemia.

Exenatide modulates visual cortex responses.

BACKGROUND: Increasing evidence suggests that metabolism affects brain physiology. Here, we examine the effect of GLP-1 on simple visual-evoked functional Magnetic Resonance Imaging (fMRI) responses in cortical areas. METHODS: Lean (n = 10) and nondiabetic obese (n = 10) subjects received exenatide (a GLP-1 agonist) or saline infusion, and fMRI responses to visual stimuli (food and nonfood images) were recorded. We analysed the effect of exenatide on fMRI signals across the cortical surface with special reference to the visual areas. We evaluated the effects of exenatide on the raw fMRI signal and on the fMRI signal change during visual stimulation (vs rest). RESULTS: In line with previous studies, we find that exenatide eliminates the preference for food (over nonfood) images present under saline infusion in high-level visual cortex (temporal pole). In addition, we find that exenatide (vs saline) also modulates the response of early visual areas, enhancing responses to both food and nonfood images in several extrastriate occipital areas, similarly in obese and lean participants. Unexpectedly, exenatide increased fMRI raw signals (signal intensity during rest periods without stimulation) in a large occipital region, which were negatively correlated to BMI. CONCLUSIONS: In both lean and obese individuals, exenatide affects neural processing in visual cortex, both in early visual areas and in higher order areas. This effect may contribute to the known effect of GLP1 analogues on food-related behaviour.

Pioglitazone prevents the increase in plasma ketone concentration associated with dapagliflozin in insulin-treated T2DM patients: Results from the Qatar Study.

Because of the unique mechanism of action of sodium-glucose co-transport inhibitors (SGLT2i), which is independent of insulin secretion and insulin action, members of this class of drugs effectively lower plasma glucose concentration when used in combination with all other antidiabetic agents, including insulin. Increased plasma ketone concentration has been reported in association with SGLT2i initiation, which, under certain clinical conditions, has developed into diabetic ketoacidosis. The daily insulin dose often is reduced at the time of initiating SGLT2i therapy in insulin-treated patients to avoid hypoglycaemia. However, reduction of insulin dose can increase the risk of ketoacidosis. In the present study, we examined the effect of the addition of dapagliflozin plus pioglitazone on plasma ketone concentration in insulin-treated T2DM patients and compared the results to the effect of dapagliflozin alone. A total of 18 poorly controlled, insulin-treated T2DM participants in the Qatar Study received dapagliflozin (10 mg) plus pioglitazone (30 mg), and 10 poorly controlled non-insulin-treated T2DM patients received dapagliflozin (10 mg) alone for 4 months. Dapagliflozin plus pioglitazone produced a robust decrease in HbA1c (-1.4%) and resulted in a 50% reduction in daily insulin dose, from 133 to 66 units, while dapagliflozin alone caused a 0.8% reduction in HbA1c. Dapagliflozin caused a four-fold increase in fasting plasma ketone concentration, while the combination of pioglitazone plus dapagliflozin was not associated with a significant increase (0.13 vs 0.15 mM) in plasma ketone concentration or in risk of hypoglycaemia. These results demonstrate that the addition of pioglitazone to dapagliflozin prevents the increase in plasma ketone concentration associated with SGLT2i therapy.

Glycated hemoglobin versus oral glucose tolerance test in the identification of subjects with prediabetes in Qatari population.

BACKGROUND: Subjects with prediabetes are at increased risk of future T2DM and cardiovascular disease (CVD) compared to NGT individuals. The OGTT (FPG = 100-125 and 2 h-PG = 140-199 mg/dl) and HbA1c 5.7-6.4% have been used to diagnose subjects with prediabetes. In the present study, we compared the ability of the OGTT and HbA1c to identify Qatari subjects with prediabetes. METHODS: Four hundred forty six subjects without a history of T2DM received 75-g OGTT and measurement of HbA1c. The incidence of prediabetes in this cohort according to OGTT criteria was compared to that of HbA1c criteria. RESULTS: The agreement between the OGTT and HbA1c in identifying subjects with prediabetes in Qatari subjects was poor, though significant (k = 015, p < 0.0001). Only 56% of participants had prediabetes or NGT according to OGTT and HbA1c. The disagreement between OGTT and HbA1c in diagnosing prediabetes was primarily due to low sensitivity of HbA1c. Moreover, subjects with prediabetes diagnosed with the OGTT have more severe metabolic profile than prediabetic subjects diagnosed with HbA1c. Lastly, more subjects with the metabolic syndrome were identified with OGTT (60%) criteria than with the HbA1c (49%), p < 0.0001. CONCLUSION: These results demonstrate subjects with prediabetes diagnosed with OGTT have more severe metabolic risk than those diagnosed with HbA1c, and more likely to have greater risk of progression to T2DM.

Reduced skeletal muscle phosphocreatine concentration in type 2 diabetic patients: a quantitative image-based phosphorus-31 MR spectroscopy study.

Mitochondrial function has been examined in insulin-resistant (IR) states including type 2 diabetes mellitus (T2DM). Previous studies using phosphorus-31 magnetic resonance spectroscopy (31P-MRS) in T2DM reported results as relative concentrations of metabolite ratios, which could obscure differences in phosphocreatine ([PCr]) and adenosine triphosphate concentrations ([ATP]) between T2DM and normal glucose tolerance (NGT) individuals. We used an image-guided 31P-MRS method to quantitate [PCr], inorganic phosphate [Pi], phosphodiester [PDE], and [ATP] in vastus lateralis (VL) muscle in 11 T2DM and 14 NGT subjects. Subjects also received oral glucose tolerance test, euglycemic insulin clamp, 1H-MRS to measure intramyocellular lipids [IMCL], and VL muscle biopsy to evaluate mitochondrial density. T2DM subjects had lower absolute [PCr] and [ATP] than NGT subjects (PCr 28.6 ± 3.2 vs. 24.6 ± 2.4, P < 0.002, and ATP 7.18 ± 0.6 vs. 6.37 ± 1.1, P < 0.02) while [PDE] was higher, but not significantly. [PCr], obtained using the traditional ratio method, showed no significant difference between groups. [PCr] was negatively correlated with HbA1c ( r = -0.63, P < 0.01) and fasting plasma glucose ( r = -0.51, P = 0.01). [PDE] was negatively correlated with Matsuda index ( r = -0.43, P = 0.03) and M/I ( r = -0.46, P = 0.04), but was positively correlated with [IMCL] ( r = 0.64, P < 0.005), HbA1c, and FPG ( r = 0.60, P = 0.001). To summarize, using a modified, in vivo quantitative 31P-MRS method, skeletal muscle [PCr] and [ATP] are reduced in T2DM, while this difference was not observed with the traditional ratio method. The strong inverse correlation between [PCr] vs. HbA1c, FPG, and insulin sensitivity supports the concept that lower baseline skeletal muscle [PCr] is related to key determinants of glucose homeostasis.