Ultra-stable insulin-glucagon fusion protein exploits an endogenous hepatic switch to mitigate hypoglycemic risk.

The risk of hypoglycemia and its serious medical sequelae restrict insulin replacement therapy for diabetes mellitus. Such adverse clinical impact has motivated development of diverse glucose-responsive technologies, including algorithm-controlled insulin pumps linked to continuous glucose monitors ("closed-loop systems") and glucose-sensing ("smart") insulins. These technologies seek to optimize glycemic control while minimizing hypoglycemic risk. Here, we describe an alternative approach that exploits an endogenous glucose-dependent switch in hepatic physiology: preferential insulin signaling (under hyperglycemic conditions) versus preferential counter-regulatory glucagon signaling (during hypoglycemia). Motivated by prior reports of glucagon-insulin co-infusion, we designed and tested an ultra-stable glucagon-insulin fusion protein whose relative hormonal activities were calibrated by respective modifications; physical stability was concurrently augmented to facilitate formulation, enhance shelf life and expand access. An N-terminal glucagon moiety was stabilized by an α-helix-compatible Lys 13 -Glu 17 lactam bridge; A C-terminal insulin moiety was stabilized as a single chain with foreshortened C domain. Studies in vitro demonstrated (a) resistance to fibrillation on prolonged agitation at 37 °C and (b) dual hormonal signaling activities with appropriate balance. Glucodynamic responses were monitored in rats relative to control fusion proteins lacking one or the other hormonal activity, and continuous intravenous infusion emulated basal subcutaneous therapy. Whereas efficacy in mitigating hyperglycemia was unaffected by the glucagon moiety, the fusion protein enhanced endogenous glucose production under hypoglycemic conditions. Together, these findings provide proof of principle toward a basal glucose-responsive insulin biotechnology of striking simplicity. The fusion protein's augmented stability promises to circumvent the costly cold chain presently constraining global insulin access. Significance Statement: The therapeutic goal of insulin replacement therapy in diabetes is normalization of blood-glucose concentration, which prevents or delays long-term complications. A critical barrier is posed by recurrent hypoglycemic events that results in short- and long-term morbidities. An innovative approach envisions co-injection of glucagon (a counter-regulatory hormone) to exploit a glycemia-dependent hepatic switch in relative hormone responsiveness. To provide an enabling technology, we describe an ultra-stable fusion protein containing insulin- and glucagon moieties. Proof of principle was obtained in rats. A single-chain insulin moiety provides glycemic control whereas a lactam-stabilized glucagon extension mitigates hypoglycemia. This dual-hormone fusion protein promises to provide a basal formulation with reduced risk of hypoglycemia. Resistance to fibrillation may circumvent the cold chain required for global access.

Efficacy and safety of basal insulins in people with type 2 diabetes mellitus: a systematic review and network meta-analysis of randomized clinical trials.

Aim: The comparative effectiveness of basal insulins has been examined in several studies. However, current treatment algorithms provide a list of options with no clear differentiation between different basal insulins as the optimal choice for initiation. Methods: A comprehensive search of MEDLINE, Embase, Cochrane Library, ISI, and Scopus, and a reference list of retrieved studies and reviews were performed up to November 2023. We identified phase III randomized controlled trials (RCTs) comparing the efficacy and safety of basal insulin regimens. The primary outcomes evaluated were HbA1c reduction, weight change, and hypoglycemic events. The revised Cochrane ROB-2 tool was used to assess the methodological quality of the included studies. A random-effects frequentist network meta-analysis was used to estimate the pooled weighted mean difference (WMD) and odds ratio (OR) with 95% confidence intervals considering the critical assumptions in the networks. The certainty of the evidence and confidence in the rankings was assessed using the GRADE minimally contextualized approach. Results: Of 20,817 retrieved studies, 44 RCTs (23,699 participants) were eligible for inclusion in our network meta-analysis. We found no significant difference among various basal insulins (including Neutral Protamine Hagedorn (NPH), ILPS, insulin glargine, detemir, and degludec) in reducing HbA1c. Insulin glargine, 300 U/mL (IGlar-300) was significantly associated with less weight gain (mean difference ranged from 2.9 kg to 4.1 kg) compared to other basal insulins, namely thrice-weekly insulin degludec (IDeg-3TW), insulin degludec, 100 U/mL (IDeg-100), insulin degludec, 200 U/mL (IDeg-200), NPH, and insulin detemir (IDet), but with low to very low certainty regarding most comparisons. IDeg-100, IDeg-200, IDet, and IGlar-300 were associated with significantly lower odds of overall, nocturnal, and severe hypoglycemic events than NPH and insulin lispro protamine (ILPS) (moderate to high certainty evidence). NPH was associated with the highest odds of overall and nocturnal hypoglycemia compared to others. Network meta-analysis models were robust, and findings were consistent in sensitivity analyses. Conclusion: The efficacy of various basal insulin regimens is comparable. However, they have different safety profiles. IGlar-300 may be the best choice when weight gain is a concern. In contrast, IDeg-100, IDeg-200, IDet, and IGlar-300 may be preferred when hypoglycemia is the primary concern.

Insulin Resistance/Sensitivity Measures as Screening Indicators of Metabolic-Associated Fatty Liver Disease and Liver Fibrosis.

BACKGROUND: Measures of insulin resistance (IR)/sensitivity (IS) are emerging tools to identify metabolic-associated fatty liver disease (MAFLD). However, the comprehensive assessment of the performance of various indicators is limited. Moreover, the utility of measures of IR/IS in detecting liver fibrosis remains unclear. AIMS: To evaluate the predictive ability of seventeen IR/IS and two beta cell function indices to identify MAFLD and liver fibrosis. METHODS: A cross-sectional study was conducted on individuals aged 25-75 years. Transient elastography was used to estimate liver stiffness and controlled attenuation parameter. The following measures were computed: homeostatic model assessment (HOMA/HOMA2) for IR, IS, and beta cell function; QUICKI; Bennett index; glucose/insulin; FIRI; McAuley index; Reynaud index; SPISE index; TyG; TyG-BMI; TyG-WC; TyG-WHtR; TG/HDL; and METS-IR. Subgroup analyses were performed according to age, gender, diabetes status, and body weight. RESULTS: A total of 644 individuals were included in our analysis. MAFLD and significant liver fibrosis were detected in 320 (49.7%) and 80 (12.4%) of the participants, respectively. All measures of IR/IS identified MAFLD and liver fibrosis. However, TyG-WC, TyG-BMI, and TyG-WHtR were the top three indicators that identified MAFLD. Measures that include insulin level in their mathematical calculation, namely, Raynaud index, HOMA-IR, HOMA 2-IR, FIRI, and QUICKI had the best performance in identifying liver fibrosis in the entire population, as well as among the study subgroups. CONCLUSIONS: TyG-WC, TyG-BMI, and TyG-WHtR were the best predictors of MAFLD. Insulin-based measures had better performances in the detection of advanced fibrosis. This was independent of age, gender, obesity, or diabetes status.

Empagliflozin improves high-sensitive cardiac troponin-I and high-density lipoprotein cholesterol in patients with type 2 diabetes mellitus and coronary artery disease: a post-hoc analysis of EMPA-CARD Trial.

Background: Empagliflozin is a sodium glucose cotransporter-2 (SGLT2) inhibitor that has been suggested to improve cardiac function and vascular recovery. The risk of coronary artery diseases is much higher in diabetic patients and is associated with greater morbidity and mortality. High-sensitivity cardiac troponin-I (hs-cTnI) is an important prognostic biomarker in cardiac diseases. Therefore, this study aimed to investigate the effect of empagliflozin compared to placebo on changes in hs-cTnI and lipid profile after 26 weeks of treatment. Methods: This was an ancillary study in a randomized trial of patients with concomitant type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD) (The EMPA-CARD study). Patients who were already on standard anti-diabetic/anti-ischemic medications were randomized to receive either placebo or empagliflozin 10 mg/daily. Serum hs-cTnI and lipid profile were measured at baseline and after 26 weeks. Results: Of the 95 randomized patients, hs-cTnI and lipid profile were measured for a total of 77 patients. No significant difference was observed regarding the baseline characteristics between the two arms. Compared to placebo, empagliflozin significantly reduced hs-cTnI after 26 weeks (mean difference (MD) of -13.242, 95%CI: -14.151 to -12.333, p < 0.001). In the empagliflozin group, non-significant reductions in total cholesterol, LDL-C, and triglyceride have resulted; however, there was an increase in HDL-C level (MD = 2.40,95%CI:0.16-4.60, p < 0.04). Conclusion: Empagliflozin compared to placebo was superior in reducing circulating hs-cTnI that may indicate improvements in cardiomyocytes function in patients with T2DM and CAD. Moreover, empagliflozin had a modest impact on the serum lipid profile biomarkers. Trial registration: The original EMPA-CARD study has been registered in Iranian Registry of Clinical Trials. www.IRCT.ir, Identifier: IRCT20190412043247N2. Registration Date: 6/13/2020. Registration timing: prospective.

The effect of sodium-glucose co-transporter-2 (SGLT2) inhibitors on blood interleukin-6 concentration: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: The low-grade chronic inflammation in diabetes plays an important role in development of cardiovascular and renal complications. Sodium-glucose co-transporter-2 (SGLT2) inhibitors are recognized as protective agents for cardio-renal complications. Interleukin-6 (IL-6) is positively associated with the pathophysiology of metabolic-related pathologies. The aim of this meta-analysis is to investigate the effect of SGLT2 inhibitors on blood IL-6 concentration in randomized controlled trials (RCTs). METHODS: Embase, PubMed, and Scopus were systematically searched up to 1st of November 2023. The eligible studies were RCTs with adult population that had provided blood IL-6 for both control and intervention groups. Cochrane risk-of-bias tool were for study quality assessment. Data were analyzed using random effect model via Stata statistical software. RESULTS: Eighteen studies with a total of 5311 patients were included. Of which 3222 and 2052 patients were in intervention and control arm, respectively. Of the total population, 49.7% were men. The study durations ranged from 8 to 52 weeks. The pooled analysis showed a significant association between the use of SGLT2 inhibitors and lower IL-6 levels (standardized mean difference (SMD) = -1.04, Confidence Interval (CI): -1.48; -0.60, I2 = 96.93%). Dapagliflozin was observed to have a higher IL-6-lowering effect (SMD = -1.30, CI: -1.89; -0.71, I2 = 92.52) than empagliflozin or canagliflozin. Sub-group analysis of control groups (SMD = -0.58 (-1.01, -0.15) and -1.35 (-2.00, -0.70 for the placebo and active control sub-groups, respectively) and duration of interventions (SMD = -0.78 (-1.28, -0.28) and -1.20 (-1.86, -0.55) for study duration of ≤ 12 and > 12 weeks, respectively) did not change the results. Meta-regression analysis showed a significant correlation between the level of HbA1c and IL-6-lowering efficacy of SGLT2 inhibitors. CONCLUSION: IL-6 levels are significantly reduced with the use of SGLT2 inhibitors with HbA1c as the only marker influencing such reductions, and dapagliflozin had the highest potency. The anti-inflammatory effect of SGLT2 inhibitors supports their broader use to address diabetic complications related to inflammatory responses.

Effect of Empagliflozin and Pioglitazone on left ventricular function in patients with type two diabetes and nonalcoholic fatty liver disease without established cardiovascular disease: a randomized single-blind clinical trial.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is a complex metabolic disorder that increases the risk for cardiovascular disease in patients with type 2 diabetes mellitus (T2DM). Global longitudinal strain (GLS) is an indicator of left ventricular (LV) mechanics and can detect subclinical myocardial dysfunction. We compared the effects of pioglitazone and empagliflozin on GLS in patients with T2DM and NAFLD without established atherosclerotic cardiovascular disease. METHODS: This study was a 24-week randomized, single-blind, and parallel-group (1: 1 ratio) clinical trial. Seventy-three participants with T2DM (being treated with metformin) and NAFLD but without established atherosclerotic cardiovascular disease (ASCVD) were randomized to empagliflozin or pioglitazone. Liver steatosis and fibrosis were measured using transient elastography, and GLS was measured by echocardiography. The primary endpoint was the change in GLS from baseline to week 24. Secondary end points include changes in controlled attenuation parameter (CAP) and Liver stiffness measure (LSM). RESULTS: In this study, GLS improved by 1.56 ± 2.34% (P < 0.01) in the pioglitazone group and 1.06 ± 1.83% (P < 0.01) in the empagliflozin group without a significant difference between the two groups (P = 0.31). At baseline, GLS was inversely associated with the severity of liver fibrosis: r = - 0.311, P = 0.007. LSM in the pioglitazone and empagliflozin group [(-0.73 ± 1.59) and (-1.11 ± 1.33)] kpa (P < 0.01) decreased significantly. It was without substantial difference between the two groups (P = 0.26). Empagliflozin and pioglitazone both improved controlled attenuation parameter. The improvement was more critical in the empagliflozin group: -48.22 + 35.02 dB/m vs. -25.67 + 41.50 dB/m, P = 0.01. CONCLUSION: Subclinical cardiac dysfunction is highly important in patients with T2DM and with NAFLD. Empagliflozin and Pioglitazone improve LV mechanics and fibrosis in patients without established ASCVD. This has a prognostic importance on cardiovascular outcomes in high-risk patients with T2DM. Moreover, empagliflozin ameliorates liver steatosis more effectively them pioglitazone. This study can serve as a start point hypothesis for the future. Further studies are needed to explore the concept in larger populations. TRIAL REGISTRATION: This trial was registered in the Iranian Registry of Clinical Trials (IRCT): "A Comparison between the Effect of Empagliflozin and Pioglitazone on Echocardiographic Indices in Patients with Type 2 Diabetes Mellitus and Nonalcoholic Fatty Liver Disease" IRCT20190122042450N5, 29 November 2020. https://www.irct.ir/search/result?query=IRCT20190122042450N5 .

Beta-cell function in type 2 diabetes (T2DM): Can it be preserved or enhanced?

Type 2 diabetes (T2DM) is a complex metabolic disorder manifested by hyperglycemia, insulin resistance, and deteriorating beta-cell function. A way to prevent progression of the disease might be to enhance beta-cell function and insulin secretion. However, most previous studies examined beta-cell function while patients were using glycemia-lowering agents without an adequate period off medications (washout). In the present review we focus on studies with a washout period. We performed a literature search (2010 to June 2021) using beta-cell function and enhancement. The evidence shows that beta-cell function can be enhanced. Bariatric surgery and very low calorie diets show improvement in beta-cell function in many individuals. In addition, use of glucagon-like peptide-1 receptor agonists for prolonged periods (3 years or more) can also lead to improvement of beta-cell function. Further research is needed to understand the mechanisms leading to improved beta-cell function and identify agents that could enhance beta-cell function in patients with T2DM.

Comparative Effects of Glucose-Lowering Medications on Kidney Outcomes in Type 2 Diabetes: The GRADE Randomized Clinical Trial.

Importance: Type 2 diabetes (T2D) is the leading cause of kidney disease in the US. It is not known whether glucose-lowering medications differentially affect kidney function. Objective: To evaluate kidney outcomes in the Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness (GRADE) trial comparing 4 classes of glucose-lowering medications added to metformin for glycemic management in individuals with T2D. Design, Setting, and Participants: A randomized clinical trial was conducted at 36 sites across the US. Participants included adults with T2D for less than 10 years, a hemoglobin A1c level between 6.8% and 8.5%, and estimated glomerular filtration rate (eGFR) greater than or equal to 60 mL/min/1.73 m2 who were receiving metformin treatment. A total of 5047 participants were enrolled between July 8, 2013, and August 11, 2017, and followed up for a mean of 5.0 years (range, 0-7.6 years). Data were analyzed from February 21, 2022, to March 27, 2023. Interventions: Addition of insulin glargine, glimepiride, liraglutide, or sitagliptin to metformin, with the medication combination continued until the HbA1c was greater than 7.5%; thereafter, insulin was added to maintain glycemic control. Main Outcomes and Measures: Chronic eGFR slope (change in eGFR between year 1 and trial end) and a composite kidney disease progression outcome (albuminuria, dialysis, transplant, or death due to kidney disease). Secondary outcomes included incident eGFR less than 60 mL/min/1.73 m2, 40% decrease in eGFR to less than 60 mL/min/1.73 m2, doubling of urine albumin-to-creatinine ratio (UACR) to 30 mg/g or greater, and progression of Kidney Disease Improving Global Outcomes stage. Analyses were intention-to-treat. Results: Of the 5047 participants, 3210 (63.6%) were men. Baseline characteristics were mean (SD) age 57.2 (10.0) years; HbA1c 7.5% (0.5%); diabetes duration, 4.2 (2.7) years; body mass index, 34.3 (6.8); blood pressure 128.3/77.3 (14.7/9.9) mm Hg; eGFR 94.9 (16.8) mL/min/1.73 m2; and median UACR, 6.4 (IQR 3.1-16.9) mg/g; 2933 (58.1%) were treated with renin-angiotensin-aldosterone inhibitors. Mean chronic eGFR slope was -2.03 (95% CI, -2.20 to -1.86) mL/min/1.73 m2 per year for patients receiving sitagliptin; glimepiride, -1.92 (95% CI, -2.08 to -1.75) mL/min/1.73 m2 per year; liraglutide, -2.08 (95% CI, -2.26 to -1.90) mL/min/1.73 m2 per year; and insulin glargine, -2.02 (95% CI, -2.19 to -1.84) mL/min/1.73 m2 per year (P = .61). Mean composite kidney disease progression occurred in 135 (10.6%) patients receiving sitagliptin; glimepiride, 155 (12.4%); liraglutide, 152 (12.0%); and insulin glargine, 150 (11.9%) (P = .56). Most of the composite outcome was attributable to albuminuria progression (98.4%). There were no significant differences by treatment assignment in secondary outcomes. There were no adverse kidney events attributable to medication assignment. Conclusions and Relevance: In this randomized clinical trial, among people with T2D and predominantly free of kidney disease at baseline, no significant differences in kidney outcomes were observed during 5 years of follow-up when a dipeptidyl peptidase 4 inhibitor, sulfonylurea, glucagonlike peptide 1 receptor agonist, or basal insulin was added to metformin for glycemic control. Trial Registration: ClinicalTrials.gov Identifier: NCT01794143.

The effect of EMPAgliflozin on markers of inflammation in patients with concomitant type 2 diabetes mellitus and Coronary ARtery Disease: the EMPA-CARD randomized controlled trial.

Systemic inflammation and oxidative burden in patients with type 2 diabetes mellitus (T2DM) causes deleterious cardiovascular outcomes. We sought to investigate the clinical antioxidative and anti-inflammatory effects of empagliflozin. Platelet function, oxidant and antioxidant biomarkers and pro-inflammatory agents at baseline and at 26 weeks were measured. A total of 95 patients (41.05% male, mean age 62.85 ± 7.91 years, mean HbA1c 7.89 ± 0.96%) with concomitant T2DM and coronary artery disease (CAD) were randomized (1:1) to receive empagliflozin (10 mg/daily) or placebo. Patients treated with empagliflozin had lower levels of interleukin 6 (IL-6) (adjusted difference (adiff): - 1.06 pg/mL, 95% CI - 1.80; - 0.32, P = 0.006), interleukin 1ß (IL-1ß) and high-sensitive C-reactive protein (Hs-CRP) (adiff: - 4.58 pg/mL and - 2.86 mg/L; P = 0.32 and 0.003, respectively) compared to placebo. There were elevations in super oxidase dismutase (SOD) activity, glutathione (GSHr), and total antioxidant capacity (TAC) with empagliflozin (adiff: 3.7 U/mL, 0.57 muM, and 124.08 mmol/L, 95% CI 1.36; 6.05, 0.19; 0.95, and 47.98; 200.18, P = 0.002, 0.004, and 0.002, respectively). While reactive oxygen species (ROS) improved significantly (adiff: - 342.51, 95% CI - 474.23; - 210.79, P < 0.001), the changes in catalase activity (CAT), malondialdehyde (MDA), or protein carbonyl groups (PCG) were not significant. Moreover, the P-selectin antigen expression on platelet surface was significantly reduced (adiff: - 8.81, 95% CI - 14.87; - 2.75, P = 0.005). Markers of glycemic status (fasting blood glucose, HbA1c, and HOMA-IR (homeostatic model assessment for insulin resistance) significantly improved (P < 0.001). Among patients with T2DM and CAD, 6-month treatment with empagliflozin can mitigate inflammation, platelet activity and oxidative stress and is associated with clinical cardiovascular benefits.Trial Registration Iranian Registry of Clinical Trials. www.IRCT.ir , Identifier: IRCT20190412043247N2. Registration Date: 6/13/2020. Registration timing: prospective.

Peptide Model of the Mutant Proinsulin Syndrome. I. Design and Clinical Correlation.

The mutant proinsulin syndrome is a monogenic cause of diabetes mellitus due to toxic misfolding of insulin's biosynthetic precursor. Also designated mutant INS-gene induced diabetes of the young (MIDY), this syndrome defines molecular determinants of foldability in the endoplasmic reticulum (ER) of ß-cells. Here, we describe a peptide model of a key proinsulin folding intermediate and variants containing representative clinical mutations; the latter perturb invariant core sites in native proinsulin (LeuB15→Pro, LeuA16→Pro, and PheB24→Ser). The studies exploited a 49-residue single-chain synthetic precursor (designated DesDi), previously shown to optimize in vitro efficiency of disulfide pairing. Parent and variant peptides contain a single disulfide bridge (cystine B19-A20) to provide a model of proinsulin's first oxidative folding intermediate. The peptides were characterized by circular dichroism and redox stability in relation to effects of the mutations on (a) in vitro foldability of the corresponding insulin analogs and (b) ER stress induced in cell culture on expression of the corresponding variant proinsulins. Striking correlations were observed between peptide biophysical properties, degree of ER stress and age of diabetes onset (neonatal or adolescent). Our findings suggest that age of onset reflects the extent to which nascent structure is destabilized in proinsulin's putative folding nucleus. We envisage that such peptide models will enable high-resolution structural studies of key folding determinants and in turn permit molecular dissection of phenotype-genotype relationships in this monogenic diabetes syndrome. Our companion study (next article in this issue) employs two-dimensional heteronuclear NMR spectroscopy to define site-specific perturbations in the variant peptides.

The cross-sectional association of cognition with diabetic peripheral and autonomic neuropathy-The GRADE study.

BACKGROUND: Studies examining whether measures of cognition are related to the presence of diabetic peripheral neuropathy (DPN) and/or cardiovascular autonomic neuropathy (CAN) are lacking, as are data regarding factors potentially explaining such associations. METHODS: Participants were from the Glycemia Reduction Approaches in Diabetes Study (GRADE) that examined 5047 middle-aged people with type 2 diabetes of <10 years of known duration. Verbal learning and immediate and delayed recall (memory) were assessed with the Spanish English Verbal Learning Test; frontal executive function and processing speed with the Digit Symbol Substitution Test; and ability to concentrate and organize data with word and animal fluency tests. DPN was assessed with the Michigan Neuropathy Screening Instrument and CAN by indices of heart rate variability (standard deviation of normal beat to beat variation [SDNN] and root mean square of successive differences [RMSSD]). RESULTS: DPN was significantly inversely related to measures of immediate recall and processing speed. The percent of cognitive variation explained by DPN was small. Tests of CAN had an inconsistent or absent association with measures of cognition. Higher waist circumference and urine albumin creatinine (UACR) levels were the strongest correlates in the relationship between DPN and cognitive impairment. CONCLUSION: DPN, but not CAN, was cross-sectionally associated with lower performance in measures of cognition in people with type 2 diabetes of <10 years of known duration. Greater waist circumference and UACR were important variables in this association. The mechanisms underlying the cross-sectional association of DPN with cognitive impairment are unknown. Clinicaltrials.gov: NCT01794143.

Shape of the OGTT glucose response curve: relationship with ß-cell function and differences by sex, race, and BMI in adults with early type 2 diabetes treated with metformin.

INTRODUCTION: The shape of the glucose curve during an oral glucose tolerance test (OGTT) reflects ß-cell function in populations without diabetes but has not been as well studied in those with diabetes. A monophasic shape has been associated with higher risk of diabetes, while a biphasic pattern has been associated with lower risk. We sought to determine if phenotypic or metabolic characteristics were associated with glucose response curve shape in adults with type 2 diabetes treated with metformin alone. RESEARCH DESIGN AND METHODS: This is a cross-sectional analysis of 3108 metformin-treated adults with type 2 diabetes diagnosed <10 years who underwent 2-hour 75 g OGTT at baseline as part of the Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study (GRADE). Insulin sensitivity (homeostasis model of insulin sensitivity, HOMA2-S) and ß-cell function (early, late, and total incremental insulin and C peptide responses adjusted for HOMA2-S) were calculated. Glucose curve shape was classified as monophasic, biphasic, or continuous rise. RESULTS: The monophasic profile was the most common (67.8% monophasic, 5.5% biphasic, 26.7% continuous rise). The monophasic subgroup was younger, more likely male and white, and had higher body mass index (BMI), while the continuous rise subgroup was more likely female and African American/black. HOMA2-S and fasting glucose did not differ among the subgroups. The biphasic subgroup had the highest early, late, and total insulin and C peptide responses (all p<0.05 vs monophasic and continuous rise). Compared with the monophasic subgroup, the continuous rise subgroup had similar early insulin (p=0.3) and C peptide (p=0.6) responses but lower late insulin (p<0.001) and total insulin (p=0.008) and C peptide (p<0.001) responses. CONCLUSIONS: Based on the large multiethnic GRADE cohort, sex, race, age, and BMI were found to be important determinants of the shape of the glucose response curve. A pattern of a continuously rising glucose at 2 hours reflected reduced ß-cell function and may portend increased glycemic failure rates. TRIAL REGISTRATION NUMBER: NCT01794143.

Study rationale and design of a study of EMPAgliflozin's effects in patients with type 2 diabetes mellitus and Coronary ARtery disease: the EMPA-CARD randomized controlled trial.

BACKGROUND: Recent trials have revealed that sodium-glucose co-transporter 2 inhibitors (SGLT2-i) are effective against hyperglycemia and also reduce micro- and macro-vascular complications in patients with type 2 diabetes mellitus (T2DM). Most of the beneficial cardiovascular effects have been investigated in patients with heart failure and coronary artery disease (CAD). Yet, few human studies have been conducted to investigate the molecular mechanisms underlying these clinically beneficial effects in patients with CAD. Accordingly, the EMPA-CARD trial was designed to focus on the molecular effects of empagliflozin in patients with T2DM and CAD. METHODS: In this multicenter, triple-blind randomized controlled trial, patients with documented known T2DM and CAD will be recruited. They will be randomized on a 1:1 ratio and assigned into two groups of empagliflozin 10 mg/daily and placebo. The primary endpoint is the effect of empagliflozin on changes of plasma interleukin 6 (IL-6) after 26 weeks of treatment. The secondary endpoints will consist of changes in other inflammatory biomarkers (Interleukin 1-beta and high-sensitive C-reactive protein), markers of oxidative stress, platelet function, and glycemic status. DISCUSSION: The EMPA-CARD trial mainly tests the hypothesis that SGLT2 inhibition by empagliflozin may improve inflammatory status measured as reduction in inflammatory biomarkers in patients with T2DM and CAD. The results will provide information about the underlying mechanisms of SGLT2 inhibition that mediate the beneficial effects of this medication on clinical outcomes. TRIAL REGISTRATION: Iranian Registry of Clinical Trials. www.IRCT.ir , Identifier: IRCT20190412043247N2. Registration Date: 6/13/2020. Registration timing: prospective.

Association of glycemia with insulin sensitivity and ß-cell function in adults with early type 2 diabetes on metformin alone.

AIMS: Evaluate the relationship between measures of glycemia with ß-cell function and insulin sensitivity in adults with early type 2 diabetes mellitus (T2DM). METHODS: This cross-sectional analysis evaluated baseline data from 3108 adults with T2DM <10 years treated with metformin alone enrolled in the Glycemia Reduction Approaches in Diabetes. A Comparative Effectiveness (GRADE) Study. Insulin and C-peptide responses and insulin sensitivity were calculated from 2-h oral glucose tolerance tests. Regression models evaluated the relationships between glycemic measures (HbA1c, fasting and 2-h glucose), measures of ß-cell function and insulin sensitivity. RESULTS: Insulin and C-peptide responses were inversely associated with insulin sensitivity. Glycemic measures were inversely associated with insulin and C-peptide responses adjusted for insulin sensitivity. HbA1c demonstrated modest associations with ß-cell function (range: r - 0.22 to -0.35). Fasting and 2-h glucose were associated with early insulin and C-peptide responses (range: r - 0.37 to -0.40) as well as late insulin and total insulin and C-peptide responses (range: r - 0.50 to -0.60). CONCLUSION: Glycemia is strongly associated with ß-cell dysfunction in adults with early T2DM treated with metformin alone. Efforts to improve glycemia should focus on interventions aimed at improving ß-cell function. This Trial is registered in Clinicaltrials.gov as NCT01794143.

Empagliflozin Improves Liver Steatosis and Fibrosis in Patients with Non-Alcoholic Fatty Liver Disease and Type 2 Diabetes: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial.

INTRODUCTION: To evaluate the efficacy of empagliflozin compared to pioglitazone in patients with non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes (T2DM). METHODS: In this prospective randomized, double-blind, placebo-controlled trial, we assigned 106 patients with NAFLD and T2DM to receive empagliflozin 10 mg (n = 35), pioglitazone 30 mg (n = 34), or placebo (n = 37) for 24 weeks. Liver fat content and liver stiffness were measured using fibroscans. Body composition assessment was performed by dual-energy x-ray absorptiometry (DEXA) scans. The primary end point was change from baseline in liver steatosis, using the controlled attenuation parameter (CAP) score. RESULTS: A borderline significant decrease in CAP score was observed with empagliflozin compared to placebo, mean difference: - 29.6 dB/m (- 39.5 to - 19.6) versus - 16.4 dB/m (- 25.0 to - 7.8), respectively; p = 0.05. Using multivariate analysis, we observed a significant reduction in the placebo-corrected change in liver stiffness measurement (LSM) with empagliflozin compared to pioglitazone: - 0.77 kPa (- 1.45, - 0.09), p = 0.02, versus 0.01 kPa (95% CI - 0.70, 0.71, p = 0.98), p for comparison = 0.03. Changes in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT), fasting insulin, homeostatic model assessment for insulin resistance (HOMA-IR), HOMA2-IR, fibrosis-4 index (FIB4 index), NAFLD fibrosis score, aspartate aminotransferase to platelet ratio index (APRI), android/gynecoid ratio (A/G ratio), and skeletal muscle index (SMI) were comparable between the two treatment groups, while significant reductions of the body weight and visceral fat area were observed only in the empagliflozin group (p < 0.001 and p = 0.01, respectively) and both were increased in the placebo and pioglitazone groups. There were no serious adverse events in either group. CONCLUSION: Treatment for 24 weeks with empagliflozin, in contrast to pioglitazone, was associated with improvement of liver steatosis and fibrosis in patients with NAFLD and T2DM. In addition, body weight and abdominal fat area were decreased in the empagliflozin group. TRIAL REGISTRATION: Iranian Registry of Clinical Trials (IRCT), IRCT20190122042450N3.

Association of Baseline Characteristics With Insulin Sensitivity and ß-Cell Function in the Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness (GRADE) Study Cohort.

OBJECTIVE: We investigated sex and racial differences in insulin sensitivity, ß-cell function, and glycated hemoglobin (HbA1c) and the associations with selected phenotypic characteristics. RESEARCH DESIGN AND METHODS: This is a cross-sectional analysis of baseline data from 3,108 GRADE (Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study) participants. All had type 2 diabetes diagnosed <10 years earlier and were on metformin monotherapy. Insulin sensitivity and ß-cell function were evaluated using the HOMA of insulin sensitivity and estimates from oral glucose tolerance tests, including the Matsuda Index, insulinogenic index, C-peptide index, and oral disposition index (DI). RESULTS: The cohort was 56.6 ± 10 years of age (mean ± SD), 63.8% male, with BMI 34.2 ± 6.7 kg/m2, HbA1c 7.5 ± 0.5%, and type 2 diabetes duration 4.0 ± 2.8 years. Women had higher DI than men but similar insulin sensitivity. DI was the highest in Black/African Americans, followed by American Indians/Alaska Natives, Asians, and Whites in descending order. Compared with Whites, American Indians/Alaska Natives had significantly higher HbA1c, but Black/African Americans and Asians had lower HbA1c. However, when adjusted for glucose levels, Black/African Americans had higher HbA1c than Whites. Insulin sensitivity correlated inversely with BMI, waist-to-hip ratio, triglyceride-to-HDL-cholesterol ratio (TG/HDL-C), and the presence of metabolic syndrome, whereas DI was associated directly with age and inversely with BMI, HbA1c, and TG/HDL-C. CONCLUSIONS: In the GRADE cohort, ß-cell function differed by sex and race and was associated with the concurrent level of HbA1c. HbA1c also differed among the races, but not by sex. Age, BMI, and TG/HDL-C were associated with multiple measures of ß-cell function and insulin sensitivity.

Evolution of insulin at the edge of foldability and its medical implications.

Proteins have evolved to be foldable, and yet determinants of foldability may be inapparent once the native state is reached. Insight has emerged from studies of diseases of protein misfolding, exemplified by monogenic diabetes mellitus due to mutations in proinsulin leading to endoplasmic reticulum stress and ß-cell death. Cellular foldability of human proinsulin requires an invariant Phe within a conserved crevice at the receptor-binding surface (position B24). Any substitution, even related aromatic residue TyrB24, impairs insulin biosynthesis and secretion. As a seeming paradox, a monomeric TyrB24 insulin analog exhibits a native-like structure in solution with only a modest decrement in stability. Packing of TyrB24 is similar to that of PheB24, adjoining core cystine B19-A20 to seal the core; the analog also exhibits native self-assembly. Although affinity for the insulin receptor is decreased ∼20-fold, biological activities in cells and rats were within the range of natural variation. Together, our findings suggest that the invariance of PheB24 among vertebrate insulins and insulin-like growth factors reflects an essential role in enabling efficient protein folding, trafficking, and secretion, a function that is inapparent in native structures. In particular, we envision that the para-hydroxyl group of TyrB24 hinders pairing of cystine B19-A20 in an obligatory on-pathway folding intermediate. The absence of genetic variation at B24 and other conserved sites near this disulfide bridge-excluded due to ß-cell dysfunction-suggests that insulin has evolved to the edge of foldability. Nonrobustness of a protein's fitness landscape underlies both a rare monogenic syndrome and "diabesity" as a pandemic disease of civilization.

Effect of Empagliflozin on Liver Steatosis and Fibrosis in Patients With Non-Alcoholic Fatty Liver Disease Without Diabetes: A Randomized, Double-Blind, Placebo-Controlled Trial.

INTRODUCTION: Despite the high prevalence of non-alcoholic fatty liver disease (NAFLD) and its associated co-morbidities, no efficient treatment in a high percentage of individuals is available. Beneficial effects of sodium-glucose co-transporter 2 inhibitors on fatty liver have been investigated in people with type 2 diabetes (T2DM). The aim of this study was to explore the effect of empagliflozin on liver steatosis and fibrosis in patients with NAFLD without T2DM. METHODS: In this prospective randomized, double-blind, placebo-controlled clinical trial, participants with NAFLD were randomized to empagliflozin (10 mg/day) (n = 43) or placebo (n = 47) for 24 weeks. Hepatic steatosis and fibrosis were assessed using transient elastography to measure the controlled attenuation parameter (CAP) and liver stiffness measurement (LSM). The primary outcome was the change in CAP score at 24 weeks. RESULTS: There was significant decrease in CAP score in both groups but no significant difference was observed between the two groups (P = 0.396). LSM was significantly decreased in the empagliflozin-treated group (6.03 ± 1.40 to 5.33 ± 1.08 kPa; P = 0.001), while no change was found in the placebo group. In subgroups analysis of patients with significant steatosis at baseline (CAP ≥ 302 dB/m), steatosis significantly improved in the empagliflozin group (37.2% vs. 17%; P = 0.035). There was a significant decrease in the grade of liver fat on visual analysis of ultrasound images, AST, ALT, and fasting insulin levels in the empagliflozin group, while no changes were observed in the placebo group. CONCLUSIONS: Empagliflozin improves liver steatosis and, more importantly, measures of liver fibrosis in patients with NAFLD without T2DM. TRIAL REGISTRATION: ClinicalTrials.gov identifier, IRCT20190122042450N1.

Factors leading to high morbidity and mortality of COVID-19 in patients with type 2 diabetes.

Coronavirus disease 2019 (COVID-19) is a recent pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel coronavirus. Diabetes (mostly type 2 diabetes mellitus, T2DM) and hyperglycemia are among the major comorbidities in patients with COVID-19 leading to poor outcomes. Reports show that patients with diabetes and COVID-19 are at an increased risk for developing severe complications including acute respiratory distress syndrome, multi-organ failure, and death. Here we explore potential mechanistic links that could explain the observed higher morbidity and mortality in this patient population. Patients with T2DM have an underlying increased level of inflammation associated with obesity and insulin resistance in addition to other comorbidities including hypertension, obesity, cardiovascular disease, dyslipidemia, and being older. We review evidence that T2DM with hyperglycemia are among factors that lead to elevated expression of angiotensin-converting enzyme 2 (ACE2) in lungs and other tissues; ACE2 is the cellular "receptor" and port of viral entry. The preexisting chronic inflammation with augmented inflammatory response to the infection and the increasing viral load leads to extreme systemic immune response ("cytokine storm") that is strongly associated with increased severity of COVID-19. Based on the available evidence, it is recommended by a panel of experts that safe but stringent control of blood glucose, blood pressure, and lipids be carried out in patients with T2DM, measures that could potentially serve to decrease the severity of COVID-19 should these patients contract the viral infection. Once the infection occurs, then attention should be directed to proper glycemic control with use of insulin and frequent monitoring of blood glucose levels.

Challenging Issues in the Management of Cardiovascular Risk Factors in Diabetes During the COVID-19 Pandemic: A Review of Current Literature.

The COVID-19 outbreak was declared a pandemic on March 2020. Many patients with SARS-CoV-2 infection have underlying chronic medical conditions such as diabetes, cardiovascular disease (CVD), and hypertension. Patient-related outcomes are worse if there are associated comorbidities. We do not have enough evidence regarding the most appropriate management of patients with diabetes during COVID-19 infection. Insulin resistance and CVD together increase the inflammatory state of the body, which can contribute to and perhaps mediate the increase of COVID-19 severity. Hence, in addition to management of dysglycemia, other CVD risk factors should be targeted. We explore the possible pathophysiologic links between diabetes and COVID-19 and discuss various options to treat dysglycemia, hypertension, and dyslipidemia in the era of COVID-19.