Diurnal Cycling of Insulin Sensitivity in Type 2 Diabetes: Evidence for Deviation From Physiology at an Early Stage.

The aim of this study was to establish the contribution of insulin resistance to the morning (a.m.) versus afternoon (p.m.) lower glucose tolerance of people with type 2 diabetes (T2D). Eleven subjects with T2D (mean [SD] diabetes duration 0.79 [0.23] years, BMI 28.3 [1.8] kg/m2, A1C 6.6% [0.26%] [48.9 (2.9) mmol/mol]), treatment lifestyle modification only) and 11 matched control subjects without diabetes were monitored between 5:00 and 8:00 a.m. and p.m. (in random order) on one occasion (study 1), and on a subsequent occasion, they underwent an isoglycemic clamp (a.m. and p.m., both between 5:00 and 8:00, insulin infusion rate 10 mU/m2/min) (study 2). In study 1, plasma glucose, insulin, C-peptide, and glucagon were higher and insulin clearance lower in subjects with T2D a.m. versus p.m. and versus control subjects (P < 0.05), whereas free fatty acid, glycerol, and ß-hydroxybutyrate were lower a.m. versus p.m. However, in study 2 at identical hyperinsulinemia a.m. and p.m. (∼150 pmol/L), glucose Ra and glycerol Ra were both less suppressed a.m. versus p.m. (P < 0.05) in subjects with T2D. In contrast, in control subjects, glucose Ra was more suppressed a.m. versus p.m. Leucine turnover was no different a.m. versus p.m. In conclusion, in subjects with T2D, insulin sensitivity for glucose (liver) and lipid metabolism has diurnal cycles (nadir a.m.) opposite that of control subjects without diabetes already at an early stage, suggesting a marker of T2D. ARTICLE HIGHLIGHTS: In people with type 2 diabetes (T2D), fasting hyperglycemia is greater in the morning (a.m.) versus the afternoon (p.m.), and insulin sensitivity for glucose and lipid metabolism is lower a.m. versus p.m. This pattern is the reverse of the physiological diurnal cycle of people without diabetes who are more insulin sensitive a.m. versus p.m. These new findings have been observed in the present study in people without obesity but with recent-onset T2D, with good glycemic control, and in the absence of confounding pharmacological treatment. It is likely that the findings represent a specific marker of T2D, possibly present even in prediabetes before biochemical and clinical manifestations.

Efficacy of the holistic, psychonutritional approach of Centro DAI e Obesità di Città della Pieve in the management of type 2 diabetes among patients with obesity and dysfunctional eating.

Purpose: Dysfunctional eating is strongly associated with obesity and worsens type 2 diabetes (T2DM) outcomes. The aim of this study was to investigate the effectiveness of the psycho-nutritional treatment (PNT) of "Centro DAI e Obesità" of Città della Pieve on weight loss and glucose management in dysfunctional eaters with obesity and T2DM. Methods: PNT includes psychotherapeutical, nutritional, physical and social activities. Subjects with obesity, T2DM and dysfunctional eating habits who completed the 8 weeks residential program between 2010 and 2019 were compared with obese, T2DM, dysfunctional eaters who underwent to a conventional, hospital-based, nutritional treatment (CT). Anthropometric variables, glucolipid panel, and body composition were assessed at baseline and at the end of the program. Weight and HbA1c were also measured after one year from the completion. Results: Sixty-nine patients completed the PNT and reduced weight (-7 ± 3.2%; p < 0.001), BMI (-7 ± 3.1%; p < 0.001), and triglycerides, AST, GGT and ALT (p ≤ 0.008); glycemic control improved (HbA1c: -1.1 ± 1.5%, mean fasting glucose: -41 ± 46 mg/dl, p < 0.001). Eleven% of subjects requiring diabetes medications at baseline discontinued the therapy. In the insulin treated group (49%), mean daily units were halved (-32.6 ± 26.0, p < 0.001). At one year, weight loss (-6 ± 7.4%, p < 0.001) and HbA1c reduction (-0.52 ± 1.4%, p = 0.029) persisted. Fifty-five patients completed the CT: HbA1c reduced (p = 0.02), but weight (-0.6 ± 3.7%), BMI (-0.7 ± 3.8%), and insulin units' reduction (-2.5 ± 11.7, p = 0.20) were lower compared to the PNT. Conclusion: PNT is effective in improving T2DM management in patients with obesity and dysfunctional eating.

Mechanisms of insulin resistance after insulin-induced hypoglycemia in humans: the role of lipolysis.

OBJECTIVE: Changes in glucose metabolism occurring during counterregulation are, in part, mediated by increased plasma free fatty acids (FFAs), as a result of hypoglycemia-activated lipolysis. However, it is not known whether FFA plays a role in the development of posthypoglycemic insulin resistance as well. RESEARCH DESIGN AND METHODS: We conducted a series of studies in eight healthy volunteers using acipimox, an inhibitor of lipolysis. Insulin action was measured during a 2-h hyperinsulinemic-euglycemic clamp (plasma glucose [PG] 5.1 mmo/l) from 5:00 p.m. to 7:00 p.m. or after a 3-h morning hyperinsulinemic-glucose clamp (from 10 a.m. to 1:00 p.m.), either euglycemic (study 1) or hypoglycemic (PG 3.2 mmol/l, studies 2-4), during which FFA levels were allowed to increase (study 2), were suppressed by acipimox (study 3), or were replaced by infusing lipids (study 4). [6,6-(2)H(2)]-Glucose was infused to measure glucose fluxes. RESULTS: Plasma adrenaline, norepinephrine, growth hormone, and cortisol levels were unchanged (P > 0.2). Glucose infusion rates (GIRs) during the euglycemic clamp were reduced by morning hypoglycemia in study 2 versus study 1 (16.8 +/- 2.3 vs. 34.1 +/- 2.2 micromol/kg/min, respectively, P < 0.001). The effect was largely removed by blockade of lipolysis during hypoglycemia in study 3 (28.9 +/- 2.6 micromol/kg/min, P > 0.2 vs. study 1) and largely reproduced by replacement of FFA in study 4 (22.3 +/- 2.8 micromol/kg/min, P < 0.03 vs. study 1). Compared with study 2, blockade of lipolysis in study 3 decreased endogenous glucose production (2 +/- 0.3 vs. 0.85 +/- 0.1 micromol/kg/min, P < 0.05) and increased glucose utilization (16.9 +/- 1.85 vs. 28.5 +/- 2.7 micromol/kg/min, P < 0.05). In study 4, GIR fell by approximately 23% (22.3 +/- 2.8 micromol/kg/min, vs. study 3, P = 0.058), indicating a role of acipimox per se on insulin action. CONCLUSION: Lipolysis induced by hypoglycemia counterregulation largely mediates posthypoglycemic insulin resistance in healthy subjects, with an estimated overall contribution of approximately 39%.

Long-term effects of pioglitazone versus gliclazide on hepatic and humoral coagulation factors in patients with type 2 diabetes.

This study compared the long-term effects of pioglitazone and gliclazide on the production of coagulation factors in patients with type 2 diabetes. Patients (n=283) with glycosylated haemoglobin > 7.5% were randomised to receive either pioglitazone (30-45 mg/day) or gliclazide (80-320 mg/day) for one year. Coagulation factors were measured at baseline and at six and 12 months. While both pioglitazone and gliclazide induced a comparable improvement in glycaemic control, only pioglitazone improved insulin sensitivity. Pioglitazone significantly (p < or = 0.001) decreased circulating levels of von Willebrand factor (-9.7%, -9.4%) and plasminogen activator inhibitor-1 (-16.8 ng/ml, -12.3 ng/ml), and increased levels of antithrombin-III (+1.3 mg/dL, +1.5 mg/dL) after six and 12 months, respectively. The beneficial effects of pioglitazone on glycaemic control, lipid homeostasis, and coagulation and thrombosis, may improve vascular outcomes in patients with type 2 diabetes.

Insulin therapy and hypoglycaemia: the size of the problem.

BACKGROUND AND METHODS: Hypoglycaemia is a fact of life for people with diabetes mellitus. Mild, asymptomatic episodes occur once or twice a week in insulin-treated diabetic subjects. Asymptomatic hypoglycaemia, including nocturnal hypoglycaemia, occurs in about 25% of diabetic subjects treated with insulin therapy. Mild hypoglycaemia, if recurrent, induces unawareness of hypoglycaemia and impairs glucose counterregulation, which in turn predisposes to severe hypoglycaemia. Even brief hypoglycaemia can cause profound dysfunction of the brain. Prolonged, severe hypoglycaemia can cause permanent neurological sequels. In addition, it is possible that hypoglycaemia may accelerate the vascular complications of diabetes by increasing platelet aggregation and/or fibrinogen formation. Finally, hypoglycaemia may be fatal. Hypoglycaemia induced by insulin as treatment of type 1 diabetes mellitus (T1 DM) is not the consequence of diabetes, but invariably of the non-physiological replacement of insulin. RESULTS: A number of studies have demonstrated that by moving from non-physiological to more physiological models of insulin therapy, most of the hypoglycaemia problems may be overcome, the percentage of glycated hemoglobin (A1c) decreased, and the quality of life improved. Interestingly, in T1 DM with hypoglycaemia unawareness, prevention of hypoglycaemia reverses not only unawareness but also improves glucose counterregulation, primarily the responses of adrenaline. CONCLUSIONS: In order to best prevent hypoglycaemia, insulin should preferably be given as continuous subcutaneous infusion via a minipump (the 'golden standard') or multiple daily insulin administrations with insulin analogues (basal insulin glargine, meal insulin rapid-acting insulin analogues) in T1 DM.

Counterregulatory hormone and symptom responses to insulin-induced hypoglycemia in the postprandial state in humans.

Plasma counterregulatory hormones and symptoms were measured during hypoglycemia in the postprandial and in the fasting state in humans to establish differences in physiological responses. We studied 8 nondiabetic subjects and 10 subjects with type 1 diabetes on two different occasions during clamped insulin-induced hypoglycemia (2.4 mmol/l) in the sitting position. On one occasion, subjects ate a standard mixed meal, and on the other they remained fasting. In response to postprandial as compared with fasting hypoglycemia, nondiabetic subjects exhibited lower total symptom scores (6.6 +/- 0.4 vs. 11.5 +/- 0.8, P = 0.001), which was due to less hunger (1.1 +/- 0.1 vs. 4.2 +/- 0.2), lower suppression of plasma C-peptide (0.23 +/- 0.1 vs. 0.08 +/- 0.07 nmol/l, P = 0.032), and greater responses of plasma glucagon (248 +/- 29 vs. 163 +/- 25 ng x l(-1) x min(-1), P = 0.018), plasma adrenaline (4.5 +/- 0.6 vs. 3.1 +/- 0.4 nmol x l(-1) x min(-1), P = 0.037), norepinephrine (3.8 +/- 0.3 vs. 3.2 +/- 0.2 nmol x l(-1) x min(-1), P = 0.037), and pancreatic polypeptide (217 +/- 12 vs. 159 +/- 22 pmol x l(-1) x min(-1), P = 0.08). Except for plasma C-peptide, responses in diabetic subjects were similarly affected. Notably, in diabetic subjects responses of glucagon, which were absent in the fasting state, nearly normalized after a meal. In conclusion, in the postprandial compared with the fasting hypoglycemic state, total symptoms are less, but counterregulatory hormones are greater and responses of glucagon nearly normalize in type 1 diabetic subjects.

Intensive replacement of basal insulin in patients with type 1 diabetes given rapid-acting insulin analog at mealtime: a 3-month comparison between administration of NPH insulin four times daily and glargine insulin at dinner or bedtime.

OBJECTIVE: To establish differences in blood glucose between different regimens of optimized basal insulin substitution in type 1 diabetic patients given lispro insulin at meals, i.e., NPH injected four times a day versus glargine insulin once daily at dinner or at bedtime. RESEARCH DESIGN AND METHODS: A total of 51 patients with type 1 diabetes on intensive therapy (NPH four times/day and lispro insulin at each meal) were randomized to three different regimens of basal insulin substitution while continuing lispro insulin at meals: continuation of NPH four times/day (n = 17), once daily glargine at dinnertime (n = 17), and once daily glargine at bedtime (n = 17) for 3 months. Blood glucose targets were fasting, preprandial, and bedtime concentrations at 6.4-7.2 mmol/l and 2 h after meals at 8.0-9.2 mmol/l. The primary end point was HbA(1c). RESULTS: Mean daily blood glucose was lower with dinnertime glargine (7.5 +/- 0.2 mmol/l) or bedtime glargine (7.4 +/- 0.2 mmol/l) versus NPH (8.3 +/- 0.2 mmol/l) (P < 0.05). A greater percentage of blood glucose values were at the target value with glargine at dinner and bedtime versus those with NPH (P < 0.05). HbA(1c) at 3 months did not change with NPH but decreased with glargine at dinnertime (from 6.8 +/- 0.2 to 6.4 +/- 0.1%) and glargine at bedtime (from 7.0 +/- 0.2 to 6.6 +/- 0.1%) (P < 0.04 vs. NPH). Total daily insulin doses were similar with the three treatments, but with glargine there was an increase in basal and a decrease in mealtime insulin requirements (P < 0.05). Frequency of mild hypoglycemia (self-assisted episodes, blood glucose < or =4.0 mmol/l) was lower with glargine (dinnertime 8.1 +/- 0.8 mmol/l, bedtime 7.7 +/- 0.9 mmol/l) than with NPH (12.2 +/- 1.3 mmol/l) (episodes/patient-month, P < 0.04). In-hospital profiles confirmed outpatient blood glucose data and indicated more steady plasma insulin concentrations at night and before meals with glargine versus NPH (P < 0.05). There were no differences between glargine given at dinnertime and at bedtime. CONCLUSIONS: Regimens of basal insulin with either NPH four times/day or glargine once/day in type 1 diabetic patients both result in good glycemic control. However, the simpler glargine regimen decreases the HbA(1c) level and frequency of hypoglycemia versus NPH. In contrast to NPH, which should be given at bedtime, insulin glargine can be administered at dinnertime without deteriorating blood glucose control.

Administration of neutral protamine Hagedorn insulin at bedtime versus with dinner in type 1 diabetes mellitus to avoid nocturnal hypoglycemia and improve control. A randomized, controlled trial.

BACKGROUND: Intensive insulin treatment of type 1 diabetes mellitus increases the risk for nocturnal hypoglycemia. OBJECTIVE: To demonstrate that splitting the evening insulin regimen reduces the risk for nocturnal hypoglycemia in intensive treatment of type 1 diabetes mellitus. DESIGN: Randomized, open, two-treatment crossover trial in two 4-month periods. SETTING: University research center in Italy. PATIENTS: 22 C-peptide-negative persons with type 1 diabetes mellitus (mean age [+/-SD], 29 +/- 3 years). INTERVENTIONS: Each patient was randomly assigned to one of two insulin regimens for 4 months and then switched to the other regimen for another 4 months. The two treatment regimens were 1) mixed treatment--a mixture of human regular and neutral protamine Hagedorn (NPH) insulin administered before dinner and 2) split treatment--human regular insulin administered at dinner and NPH insulin administered at bedtime. MEASUREMENTS: Frequency of nocturnal hypoglycemia. Secondary end points were levels of fasting blood glucose and hemoglobin A1c and responses to experimental hypoglycemia. RESULTS: During the split-regimen treatment period, patients had fewer episodes of nocturnal hypoglycemia (mean [+/-SE], 0.10 +/- 0.02 episode/patient-day vs. 0.28 +/- 0.04 episode/patient-day; P = 0.002), a lower fasting blood glucose level (mean [+/-SE], 7.6 +/- 0.2 mmol/L vs. 8.3 +/- 0.5 mmol/L [137 +/- 4 mg/dL vs. 160 +/- 8 mg/dL]; P = 0.030), less variable fasting blood glucose levels (SD range, 2.0 +/- 0.4 vs. 3.5 +/- 0.6; P = 0.001), and lower hemoglobin A1c value (mean [+/-SE], 7.0% +/- 0.11% vs. 7.5% +/- 0.15%; P = 0.004) than during the mixed regimen. Responses to experimental hypoglycemia were better preserved with the split regimen than with the mixed regimen. CONCLUSION: When the goal of insulin therapy in type 1 diabetes mellitus is near-normoglycemia, splitting the evening insulin treatment regimen into short-acting insulin at dinner and NPH insulin at bedtime reduces the risks for nocturnal hypoglycemia and hypoglycemia unawareness and decreases the hemoglobin A1c value compared with mixing short-acting insulin and NPH insulin at dinner.