Ildiko Lingvay

Cardiac Steatosis in Diabetes Mellitus A 1H-Magnetic Resonance Spectroscopy Study

Background— The risk of heart failure in type 2 diabetes mellitus is greater than can be accounted for by hypertension and coronary artery disease. Rodent studies indicate that in obesity and type 2 diabetes mellitus, lipid overstorage in cardiac myocytes produces lipotoxic intermediates that cause apoptosis, which leads to heart failure. In humans with diabetes mellitus, cardiac steatosis previously has been demonstrated in explanted hearts of patients with end-stage nonischemic cardiomyopathy. Whether cardiac steatosis precedes the onset of cardiomyopathy in individuals with impaired glucose tolerance or in patients with type 2 diabetes mellitus is unknown. Methods and Results— To represent the progressive stages in the natural history of type 2 diabetes mellitus, we stratified 134 individuals (age 45±12 years) into 1 of 4 groups: (1) lean normoglycemic (lean), (2) overweight and obese normoglycemic (obese), (3) impaired glucose tolerance, and (4) type 2 diabetes mellitus. Localized 1H magnetic resonance spectroscopy and cardiac magnetic resonance imaging were used to quantify myocardial triglyceride content and left ventricular function, respectively. Compared with lean subjects, myocardial triglyceride content was 2.3-fold higher in those with impaired glucose tolerance and 2.1-fold higher in those with type 2 diabetes mellitus (P<0.05). Left ventricular ejection fraction was normal and comparable across all groups. Conclusions— In humans, impaired glucose tolerance is accompanied by cardiac steatosis, which precedes the onset of type 2 diabetes mellitus and left ventricular systolic dysfunction. Thus, lipid overstorage in human cardiac myocytes is an early manifestation in the pathogenesis of type 2 diabetes mellitus and is evident in the absence of heart failure.

Noninvasive Quantification of Pancreatic Fat in Humans

OBJECTIVE To validate magnetic resonance spectroscopy (MRS) as a tool for non-invasive quantification of pancreatic triglyceride (TG) content and to measure the pancreatic TG content in a diverse human population with a wide range of body mass index (BMI) and glucose control. METHODS To validate the MRS method, we measured TG content in the pancreatic tissue of 12 lean and 12 fatty ZDF rats (ages 5-14 weeks) both by MRS and the gold standard biochemical assay. We used MRS to measure pancreatic TG content in vivo in 79 human volunteers. Additionally, to assess the reproducibility of the method, in 33 volunteers we obtained duplicate MRS measurements 1-2 weeks apart. RESULTS MRS quantifies pancreatic TG content with high reproducibility and concordance to the biochemical measurement (Spearmans rank correlation coefficient = 0.91). In humans, median pancreatic TG content was as follows: (1) normal weight and normoglycemic group 0.46 f/w%, (2) overweight or obese but normoglycemic group 3.16 f/w%, (3) impaired fasting glucose or impaired glucose tolerance group (BMI matched with group 2) 5.64 f/w%, and (4) untreated type 2 diabetes group (BMI matched with group 2) 5.54 f/w% (Jonckheere-Terpstra trend test across groups p < 0.001). CONCLUSIONS Human pancreatic steatosis, as measured by MRS, increases with BMI and with impaired glycemia. MRS is a quantitative and reproducible non-invasive clinical research tool which will enable systematic studies of the relationship between ectopic fat accumulation in the pancreas and development of type 2 diabetes.

Insulin-Based versus Triple Oral Therapy for Newly-Diagnosed Type 2 Diabetes: Which is Better?

OBJECTIVE Early use of insulin after diagnosis of type 2 diabetes is met with resistance because of associated weight gain, hypoglycemia, and fear of decreased compliance and quality of life (QoL). RESEARCH DESIGN AND METHODS In treatment-naive patients with newly diagnosed type 2 diabetes, insulin and metformin were initiated for a 3-month lead-in period, then patients were randomly assigned to insulin and metformin (insulin group) or metformin, pioglitazone, and glyburide (oral group) for 36 months. Hypoglycemic events, compliance, A1C, weight, QoL, and treatment satisfaction were assessed. RESULTS Of 29 patients randomly assigned into each group, 83% (insulin group) and 72% (oral group) completed this 3-year study. At study completion, A1C was 6.1 ± 0.6% (insulin group) versus 6.0 ± 0.8% (oral group). Weight increased similarly in both groups (P = 0.09) by 4.47 kg (95% CI 0.89–8.04 kg) (insulin group) and 7.15 kg (95% CI 4.18–10.13 kg) (orals group). Hypoglycemic events did not differ between groups (mild 0.51 event/person-month in the insulin group vs. 0.68 event/person-month in the orals group, P = 0.18 and severe 0.04 event/person-year in the insulin group vs. 0.09 event/person-year in the orals group, P = 0.53). Compliance, QoL, and treatment satisfaction were similar between groups, with 100% of patients randomly assigned to insulin willing to continue such treatment. CONCLUSIONS When compared with a clinically equivalent treatment regimen, insulin-based therapy is effective and did not cause greater weight gain or hypoglycemia nor decrease compliance, treatment satisfaction, or QoL. Insulin is safe, well-accepted, and effective for ongoing treatment of patients with newly diagnosed type 2 diabetes.

Effect of Insulin Glargine Up-titration vs Insulin Degludec/Liraglutide on Glycated Hemoglobin Levels in Patients With Uncontrolled Type 2 Diabetes: The DUAL V Randomized Clinical Trial

IMPORTANCE Achieving glycemic control remains a challenge for patients with type 2 diabetes, even with insulin therapy. OBJECTIVE To assess whether a fixed ratio of insulin degludec/liraglutide was noninferior to continued titration of insulin glargine in patients with uncontrolled type 2 diabetes treated with insulin glargine and metformin. DESIGN, SETTING, AND PARTICIPANTS Phase 3, multinational, multicenter, 26-week, randomized, open-label, 2-group, treat-to-target trial conducted at 75 centers in 10 countries from September 2013 to November 2014 among 557 patients with uncontrolled diabetes treated with glargine (20-50 U) and metformin (≥1500 mg/d) with glycated hemoglobin (HbA1c) levels of 7% to 10% and a body mass index of 40 or lower. INTERVENTIONS 1:1 randomization to degludec/liraglutide (n = 278; maximum dose, 50 U of degludec/1.8 mg of liraglutide) or glargine (n = 279; no maximum dose), with twice-weekly titration to a glucose target of 72 to 90 mg/dL. MAIN OUTCOMES AND MEASURES Primary outcome measure was change in HbA1c level after 26 weeks, with a noninferiority margin of 0.3% (upper bound of 95% CI, <0.3%). If noninferiority of degludec/liraglutide was achieved, secondary end points were tested for statistical superiority and included change in HbA1c level, change in body weight, and rate of confirmed hypoglycemic episodes. RESULTS Among 557 randomized patients (mean: age, 58.8 years; women, 49.7%), 92.5% of patients completed the trial and provided data at 26 weeks. Baseline HbA1c level was 8.4% for the degludec/liraglutide group and 8.2% for the glargine group. HbA1c level reduction was greater with degludec/liraglutide vs glargine (-1.81% for the degludec/liraglutide group vs -1.13% for the glargine group; estimated treatment difference [ETD], -0.59% [95% CI, -0.74% to -0.45%]), meeting criteria for noninferiority (P < .001), and also meeting criteria for statistical superiority (P < .001). Treatment with degludec/liraglutide was also associated with weight loss compared with weight gain with glargine (-1.4 kg for degludec/liraglutide vs 1.8 kg for glargine; ETD, -3.20 kg [95% CI, -3.77 to -2.64],P < .001) and fewer confirmed hypoglycemic episodes (episodes/patient-year exposure, 2.23 for degludec/liraglutide vs 5.05 for glargine; estimated rate ratio, 0.43 [95% CI, 0.30 to 0.61],P < .001). Overall and serious adverse event rates were similar in the 2 groups, except for more nonserious gastrointestinal adverse events reported with degludec/liraglutide (adverse events, 79 for degludec/liraglutide vs 18 for glargine). CONCLUSIONS AND RELEVANCE Among patients with uncontrolled type 2 diabetes taking glargine and metformin, treatment with degludec/liraglutide compared with up-titration of glargine resulted in noninferior HbA1c levels, with secondary analyses indicating greater HbA1c level reduction after 26 weeks of treatment. Further studies are needed to assess longer-term efficacy and safety. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01952145.

β-Cell Function Preservation After 3.5 Years of Intensive Diabetes Therapy

OBJECTIVE To assess β-cell function preservation after 3.5 years of intensive therapy with insulin plus metformin (INS group) versus triple oral therapy (TOT group) with metformin, glyburide, and pioglitazone. RESEARCH DESIGN AND METHODS This was a randomized trial of 58 patients with treatment-naïve newly diagnosed type 2 diabetes. All patients were treated with insulin and metformin for a 3-month lead-in period followed by random assignment to the INS or TOT group. β-Cell function was assessed using a mixed-meal challenge test at randomization and 6, 12, 18, 30, and 42 months. Analyses were intention to treat and performed with repeated-measures models. RESULTS Completion rates at 3.5 years were 83% in the insulin group and 72% in the TOT group, with good compliance in both groups (87 ± 20% in the INS group vs. 90 ± 15% in the TOT group). β-Cell function was preserved at 3.5 years after diagnosis, with no significant change from baseline or difference between the two groups as measured by area under the curve (AUC) of C-peptide (P = 0.14) or the ratio of C-peptide to glucose AUC (P = 0.7). Excellent glycemic control was maintained in both groups (end-of-study HbA1c 6.35 ± 0.84% in the INS group vs. 6.59 ± 1.94% in the TOT group). Weight increased in both groups over time (from 102.2 ± 24.9 kg to 106.2 ± 31.7 kg in the INS group and from 100.9 ± 23.0 kg to 110.5 ± 31.8 kg in the TOT group), with no significant difference between groups (P = 0.35). Hypoglycemic events decreased significantly over time (P = 0.01) but did not differ between groups (P = 0.83). CONCLUSIONS β-Cell function can be preserved for at least 3.5 years with early and intensive therapy for type 2 diabetes with either insulin plus metformin or triple oral therapy after an initial 3-month insulin-based treatment period.

Rapid Improvement in Diabetes After Gastric Bypass Surgery: Is it the diet or surgery?

OBJECTIVE Improvements in diabetes after Roux-en-Y gastric bypass (RYGB) often occur days after surgery. Surgically induced hormonal changes and the restrictive postoperative diet are proposed mechanisms. We evaluated the contribution of caloric restriction versus surgically induced changes to glucose homeostasis in the immediate postoperative period. RESEARCH DESIGN AND METHODS Patients with type 2 diabetes planning to undergo RYGB participated in a prospective two-period study (each period involved a 10-day inpatient stay, and periods were separated by a minimum of 6 weeks of wash-out) in which patients served as their own controls. The presurgery period consisted of diet alone. The postsurgery period was matched in all aspects (daily matched diet) and included RYGB surgery. Glucose measurements were performed every 4 h throughout the study. A mixed-meal challenge test was performed before and after each period. RESULTS Ten patients completed the study and had the following characteristics: age, 53.2 years (95% CI, 48.0–58.4); BMI, 51.2 kg/m2 (46.1–56.4); diabetes duration, 7.4 years (4.8–10.0); and HbA1c, 8.52% (7.08–9.96). Patients lost 7.3 kg (8.1–6.5) during the presurgery period versus 4.0 kg (6.2–1.7) during the postsurgery period (P = 0.01 between periods). Daily glycemia in the presurgery period was significantly lower (1,293.58 mg/dL·day [1,096.83–1,490.33) vs. 1,478.80 mg/dL·day [1,277.47–1,680.13]) compared with the postsurgery period (P = 0.02 between periods). The improvements in the fasting and maximum poststimulation glucose and 6-h glucose area under the curve (primary outcome) were similar during both periods. CONCLUSIONS Glucose homeostasis improved in response to a reduced caloric diet, with a greater effect observed in the absence of surgery as compared with after RYGB. These findings suggest that reduced calorie ingestion can explain the marked improvement in diabetes control observed after RYGB.

Effect of Pioglitazone Therapy on Myocardial and Hepatic Steatosis in Insulin-Treated Patients with Type 2 Diabetes

High levels of myocardial and hepatic triglyceride are common in obesity and type 2 diabetes. Monotherapy with thiazolidinedione agents reduces hepatic steatosis by up to 50% in patients with type 2 diabetes. It is not known if treatment with a thiazolidinedione added to insulin has a similar beneficial antisteatotic effect. The aim of our study was to determine whether the addition of pioglitazone to insulin treatment in patients with type 2 diabetes has antisteatotic action in the heart and the liver. Thirty-two patients were randomized to 6 months of treatment with insulin or insulin plus pioglitazone. In addition to blood tests, we evaluated myocardial and hepatic triglyceride content, as well as subcutaneous and visceral fat mass at the L2 level, by magnetic resonance spectroscopy and imaging, respectively. Despite weight and subcutaneous fat mass gain, hemoglobin A1c was significantly reduced by both treatments. Myocardial and hepatic triglyceride contents were reduced by the treatment with pioglitazone plus insulin (p = .02 and .03, respectively) but not by the treatment with insulin. Systolic and diastolic blood pressure and heart function remained unchanged in both groups. The addition of pioglitazone to insulin therapy reduced myocardial and hepatic steatosis, consistent with the reported ability of the thiazolidinedione agents to redistribute fat from nonadipose to subcutaneous adipose depots.

Rapid Improvement of Diabetes After Gastric Bypass Surgery

OBJECTIVE Improvements in diabetes after Roux-en-Y gastric bypass (RYGB) often occur days after surgery. Surgically induced hormonal changes and the restrictive postoperative diet are proposed mechanisms. We evaluated the contribution of caloric restriction versus surgically induced changes to glucose homeostasis in the immediate postoperative period. RESEARCH DESIGN AND METHODS Patients with type 2 diabetes planning to undergo RYGB participated in a prospective two-period study (each period involved a 10-day inpatient stay, and periods were separated by a minimum of 6 weeks of wash-out) in which patients served as their own controls. The presurgery period consisted of diet alone. The postsurgery period was matched in all aspects (daily matched diet) and included RYGB surgery. Glucose measurements were performed every 4 h throughout the study. A mixed-meal challenge test was performed before and after each period. RESULTS Ten patients completed the study and had the following characteristics: age, 53.2 years (95% CI, 48.0–58.4); BMI, 51.2 kg/m2 (46.1–56.4); diabetes duration, 7.4 years (4.8–10.0); and HbA1c, 8.52% (7.08–9.96). Patients lost 7.3 kg (8.1–6.5) during the presurgery period versus 4.0 kg (6.2–1.7) during the postsurgery period (P = 0.01 between periods). Daily glycemia in the presurgery period was significantly lower (1,293.58 mg/dL·day [1,096.83–1,490.33) vs. 1,478.80 mg/dL·day [1,277.47–1,680.13]) compared with the postsurgery period (P = 0.02 between periods). The improvements in the fasting and maximum poststimulation glucose and 6-h glucose area under the curve (primary outcome) were similar during both periods. CONCLUSIONS Glucose homeostasis improved in response to a reduced caloric diet, with a greater effect observed in the absence of surgery as compared with after RYGB. These findings suggest that reduced calorie ingestion can explain the marked improvement in diabetes control observed after RYGB.

Pancreatic steatosis: harbinger of type 2 diabetes in obese rodents

Objective:The aim of this study was to determine if the fat accumulation in the exocrine pancreas fat of obese Zucker diabetic fatty (ZDF) rodents, like that in their endocrine pancreas, precedes the onset of type 2 diabetes mellitus (T2DM). As the fat content of whole pancreas, but not islets, can now be measured in humans by magnetic resonance spectroscopy (MRS), such measurements could be used as a predictor of impending T2DM and an indication for preventive intervention.Animals:Obese ZDF (fa/fa) rats and lean (+/+) controls on a 6% fat diet were killed at time points from 6 to 16 weeks and total pancreatic fat was measured biochemically and electronmicroscopic examination of tissue for fat droplets was carried out.Results:Compared to lean ZDF controls, pancreatic fat was elevated above lean controls from 6 to 16 weeks of age, peaking at 10 weeks of age when hyperglycemia first appeared. The pancreatic profile of fat content in whole pancreas paralleled that of islets. Electronmicroscopic examination identified the acinar location of the fat droplets and ruled out a major contribution of intrapancreatic adipocytes.Conclusion:The almost identical pattern of triglyceride overaccumulation in the exocrine and endocrine pancreas of obese rodents before the onset of T2DM suggests that MRS of the human pancreas might predict T2DM in obese subjects and permit timely interventions to prevent the disease.

Pancreatic Steatosis and Its Relationship to β-Cell Dysfunction in Humans Racial and ethnic variations

OBJECTIVE To evaluate racial/ethnic differences in pancreatic triglyceride (TG) levels and their relationship to β-cell dysfunction in humans. RESEARCH DESIGN AND METHODS We studied black, Hispanic, and white adults who completed three research visits: screening and an oral glucose tolerance test; frequently sampled intravenous glucose tolerance tests for evaluation of β-cell function and insulin resistance; and proton magnetic resonance spectroscopy for evaluation of pancreatic and hepatic TG levels. RESULTS Pancreatic TG levels were higher in Hispanics and whites than in blacks (P = 0.006). Hepatic TG levels were highest in Hispanics (P = 0.004). Compensatory insulin secretion and disposition index were higher in blacks (P = 0.003 and P = 0.024, respectively). Insulin sensitivity was comparable between Hispanics and blacks and was lower than in whites (P = 0.005). In blacks, compensatory insulin secretion increased steeply with small increments in pancreatic TG levels (R2 = 0.45, slope = 247). In whites, the range of pancreatic TG levels was higher, and the slope was less steep than in blacks (R2 = 0.27, slope = 27). In Hispanics, pancreatic TG levels were similar to those of whites, but compensatory insulin secretion was described by a combination of pancreatic and hepatic TG levels and visceral fat mass ( R2 = 0.32). CONCLUSIONS In a multiethnic sample of adults with mild obesity and without diabetes, we found striking ethnic differences in the levels of pancreatic TGs and in the relationship between pancreatic TGs and β-cell dysfunction. Our data implicate pancreatic TG content measured by proton magnetic resonance spectroscopy as a noninvasive novel biomarker for pancreatic β-cell dysfunction, especially in the Hispanic population.