Gonzalo Robalino

Insulin Analogs Versus Human Insulin in the Treatment of Patients With Diabetic Ketoacidosis: A randomized controlled trial

OBJECTIVE To compare the safety and efficacy of insulin analogs and human insulins both during acute intravenous treatment and during the transition to subcutaneous insulin in patients with diabetic ketoacidosis (DKA). RESEARCH DESIGN AND METHODS In a controlled multicenter and open-label trial, we randomly assigned patients with DKA to receive intravenous treatment with regular or glulisine insulin until resolution of DKA. After resolution of ketoacidosis, patients treated with intravenous regular insulin were transitioned to subcutaneous NPH and regular insulin twice daily (n = 34). Patients treated with intravenous glulisine insulin were transitioned to subcutaneous glargine once daily and glulisine before meals (n = 34). RESULTS There were no differences in the mean duration of treatment or in the amount of insulin infusion until resolution of DKA between intravenous treatment with regular and glulisine insulin. After transition to subcutaneous insulin, there were no differences in mean daily blood glucose levels, but patients treated with NPH and regular insulin had a higher rate of hypoglycemia (blood glucose <70 mg/dl). Fourteen patients (41%) treated with NPH and regular insulin had 26 episodes of hypoglycemia and 5 patients (15%) in the glargine and glulisine group had 8 episodes of hypoglycemia (P = 0.03). CONCLUSIONS Regular and glulisine insulin are equally effective during the acute treatment of DKA. A transition to subcutaneous glargine and glulisine after resolution of DKA resulted in similar glycemic control but in a lower rate of hypoglycemia than with NPH and regular insulin. Thus, a basal bolus regimen with glargine and glulisine is safer and should be preferred over NPH and regular insulin after the resolution of DKA.

Intravenous Intralipid-Induced Blood Pressure Elevation and Endothelial Dysfunction in Obese African-Americans with Type 2 Diabetes

OBJECTIVE Increased free fatty acids (FFAs) are leading candidates in the pathogenesis of insulin resistance and hypertension in obese subjects. We evaluated the effect of sustained elevations of FFA on blood pressure, endothelial function, insulin secretion, inflammatory markers, and renin-angiotensin system. RESEARCH DESIGN AND METHODS Twenty-four obese, African-American, normotensive diabetic subjects received a sequential 48-h infusion of Intralipid (20%, 40 ml/h) plus heparin (250 units/h) or normal saline (40 ml/h) plus heparin (250 units/h). RESULTS Blood pressure was significantly increased within 4 h of lipid infusion and reached a peak increment of 13 mm Hg in systolic and 5 mm Hg in diastolic blood pressure at 24 h (P < 0.01). Compared to baseline, lipid infusion reduced flow-mediated dilatation by 11% at 24 h and 18% at 48 h (P < 0.001). FFA and triglyceride levels increased from a baseline of 0.5 +/- 0.2 mmol/liter and 135 +/- 76 mg/dl to 1.8 +/- 1.0 mmol/liter and 376 +/- 314 mg/dl at 48 h, respectively (P < 0.01). C-Reactive protein increased by 35% at 24 h and by 110% at 48 h of lipid infusion. There were no significant changes in plasma renin and aldosterone levels during lipid or saline infusions. CONCLUSION Increased FFA levels result in a rapid and sustained elevation in blood pressure, impaired endothelial function, and increased inflammatory markers in obese subjects with type 2 diabetes. The model of FFA-induced hypertension may be useful in examining disease mechanisms associated with the development of hypertension in obese subjects.

Effects of oral and intravenous fat load on blood pressure, endothelial function, sympathetic activity, and oxidative stress in obese healthy subjects

We compared the effects of high and low oral and intravenous (iv) fat load on blood pressure (BP), endothelial function, autonomic nervous system, and oxidative stress in obese healthy subjects. Thirteen obese subjects randomly received five 8-h infusions of iv saline, 20 (32 g, low iv fat) or 40 ml/h intralipid (64 g, high iv fat), and oral fat load at 32 (low oral) or 64 g (high oral). Systolic BP increased by 14 ± 10 (P = 0.007) and 12 ± 9 mmHg (P = 0.007) after low and high iv lipid infusions and by 13 ± 17 (P = 0.045) and 11 ± 11 mmHg (P = 0.040) after low and high oral fat loads, respectively. The baseline flow-mediated dilation was 9.4%, and it decreased by 3.8 ± 2.1 (P = 0.002) and 4.1 ± 3.1% (P < 0.001) after low and high iv lipid infusion and by 3.8 ± 1.8 (P = 0.002) and 5.0 ± 2.5% (P < 0.001) after low and high oral fat load, respectively. Oral and iv fat load stimulated oxidative stress, increased heart rate, and decreased R-R interval variability. Acute iv fat load decreased blood glucose by 6-10 mg/dl (P < 0.05) without changes in insulin concentration, whereas oral fat increased plasma insulin by 3.7-4.0 μU/ml (P < 0.01) without glycemic variations. Intravenous saline and both oral and iv fat load reduced leptin concentration from baseline (P < 0.01). In conclusion, acute fat load administered orally or intravenously significantly increased blood pressure, altered endothelial function, and activated sympathetic nervous system by mechanisms not likely depending on changes in leptin, glucose, and insulin levels in obese healthy subjects. Thus, fat load, independent of its source, has deleterious hemodynamic effects in obese subjects.

Effects of Intravenous Glucose Load on Insulin Secretion in Patients With Ketosis-Prone Diabetes During Near-Normoglycemia Remission

OBJECTIVE Most patients with ketosis-prone type 2 diabetes (KPD) discontinue insulin therapy and remain in near-normoglycemic remission. The aim of this study was to determine the effect of glucotoxicity on β-cell function during remission in obese patients with KPD. RESEARCH DESIGN AND METHODS Age- and BMI-matched obese African Americans with a history of KPD (n = 8), severe hyperglycemia but without ketosis (ketosis-resistant type 2 diabetes, n = 7), and obese control subjects (n = 13) underwent intravenous infusion of 10% dextrose at a rate of 200 mg per m2/min for 20 h. β-Cell function was assessed by changes in insulin and C-peptide concentrations during dextrose infusion and by changes in acute insulin response (AIR) and first-phase insulin release (FPIR) to arginine stimulation before and after dextrose infusion. RESULTS The mean ± SD time to discontinue insulin therapy was 7.1 ± 1.7 weeks in KPD and 9.6 ± 2.3 weeks in ketosis-resistant type 2 diabetes (NS). During a 20-h dextrose infusion, changes in insulin, C-peptide, and the C-peptide–to–glucose ratio were similar among diabetic and control groups. During dextrose infusion, subjects with ketosis-resistant type 2 diabetes had greater areas under the curve for blood glucose than subjects with KPD and control subjects (P < 0.05). The AIR and FPIR to arginine stimulation as well as glucose potentiation to arginine assessed before and after dextrose infusion were not different among the study groups. CONCLUSIONS Near-normoglycemia remission in obese African American patients with KPD and ketosis-resistant type 2 diabetes is associated with a remarkable recovery in basal and stimulated insulin secretion. At near-normoglycemia remission, patients with KPD displayed a pattern of insulin secretion similar to that of patients with ketosis-resistant type 2 diabetes and obese nondiabetic subjects.

Lack of Lipotoxicity Effect on β-Cell Dysfunction in Ketosis-Prone Type 2 Diabetes

OBJECTIVE Over half of newly diagnosed obese African Americans with diabetic ketoacidosis (DKA) discontinue insulin therapy and go through a period of near-normoglycemia remission. This subtype of diabetes is known as ketosis-prone type 2 diabetes (KPDM). RESEARCH DESIGN AND METHODS To investigate the role of lipotoxicity on β-cell function, eight obese African Americans with KPDM, eight obese subjects with type 2 diabetes with severe hyperglycemia without ketosis (ketosis-resistant type 2 diabetes), and nine nondiabetic obese control subjects underwent intravenous infusion of 20% intralipid at 40 ml/h for 48 h. β-Cell function was assessed by changes in insulin and C-peptide concentration during infusions and by changes in acute insulin response to arginine stimulation (AIRarg) before and after lipid infusion. RESULTS The mean time to discontinue insulin therapy was 11.0 ± 8.0 weeks in KPDM and 9.6 ± 2.2 weeks in ketosis-resistant type 2 diabetes (P = NS). At remission, KPDM and ketosis-resistant type 2 diabetes had similar glucose (94 ± 14 vs. 109 ± 20 mg/dl), A1C (5.7 ± 0.4 vs. 6.3 ± 1.1%), and baseline AIRarg response (34.8 ± 30 vs. 64 ± 69 μU/ml). P = NS despite a fourfold increase in free fatty acid (FFA) levels (0.4 ± 0.3 to 1.8 ± 1.1 mmol/l, P < 0.01) during the 48-h intralipid infusion; the response to AIRarg stimulation, as well as changes in insulin and C-peptide levels, were similar among obese patients with KPDM, patients with ketosis-resistant type 2 diabetes, and nondiabetic control subjects. CONCLUSIONS Near-normoglycemia remission in obese African American patients with KPDM and ketosis-resistant type 2 diabetes is associated with a remarkable recovery in basal and stimulated insulin secretion. A high FFA level by intralipid infusion for 48 h was not associated with β-cell decompensation (lipotoxicity) in KPDM patients.

293 MICROARRAY ANALYSIS OF PROTEINS INVOLVED IN SIGNAL TRANSDUCTION AND APOPTOSIS IN SKELETAL MUSCLE OF PATIENTS WITH KETOSIS-PRONE TYPE 2 DIABETES MELLITUS.

Most obese African Americans with diabetic ketoacidosis (DKA) exhibit clinical and metabolic features of type 2 diabetes and are able to discontinue insulin therapy during follow-up. These patients are characterized as having ketosis-prone type 2 diabetes mellitus (KPDM). To examine the underlying mechanisms, we examined changes in phoshorylation and expression of apoptotic and signaling proteins in skeletal muscle in patients with KPDM. Methods Six obese normoglycemic subjects (control group) and seven patients presenting with blood glucose (BG) > 400 mg/dL and/or DKA underwent percutaneous needle biopsy of the vastus lateralis muscle. Muscle biopsies were homogenized in protein lysis buffer and samples from each group were analyzed in duplicate using a commercial antibody microarray. The microarray slides contained antibodies against 350 proteins involved in cell signaling and apoptosis. Changes in phosphorylation or expression by at least 40% were considered significant. Results KPDM subjects (age 37 years, BMI 39.6 kg/m2) had an admission blood glucose 564 mg/dL and HbA1c 11.4%, whereas age- and BMI-matched controls had a BG 84 mg/dL. In KPDM patients, hyperglycemia was associated with increased phosphorylation of six isoforms of PKC and with elevated muscle expression of four isoforms of protein phosphatases, signaling through Src, Shc1, MEK1/2, MEK3/6, RSK1/2, and activation of inhibitors of apoptosis STAT 1, 3, and 5. In patients with KPDM, we observed a decrease in phosphorylation and expression of antiapoptotic and proinflammatory proteins IKKalpha and NFkappaB p65, associated with reduced p53 expression. The abundance of heat shock proteins Hsp70, 47, 40, 20, 27 and GRP 57, 94 also decreased. In addition, there was reduced phosphorylation and expression of proapoptotic JAK2, JNK MAPK, jun, and STE20-like proteins. Conclusion Compared with nondiabetic subjects, skeletal muscle from patients with KPDM at presentation were characterized by alterations in phosphorylation and expression of proteins involved in intracellular signaling, trafficking, regulation of apoptosis, and stress response. Preliminary analysis of the data indicates that hyperglycemia is associated with predominant activation of antiapoptotic mechanisms, which contrasts previously described effects of hyperglycemia in other cell types. Supported by grants from the ADA (7-03-CR-35) and NIH: R03 DK073190-01, K12-RR017643, and GCRC M01 RR-00039.