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S Pampanelli

Publications and source records attributed to S Pampanelli.

29 records · Page 2Linked to original sources

Effects of the short-acting insulin analog [Lys(B28),Pro(B29)] on postprandial blood glucose control in IDDM.

OBJECTIVE: To establish the effects of the short-acting insulin analog Lispro versus human regular insulin (Hum-R) on postprandial metabolic control in IDDM. RESEARCH DESIGN AND METHODS: Four studies were performed in 10 C-peptide-negative IDDM patients. Lispro or Hum-R (0.15 U/kg) or Lispro + NPH (0.07 U/kg) or Hum-R + NPH were injected subcutaneously 30 min (Hum-R) or 5 min (Lispro) before lunch. Preprandial plasma glucose (PG) was maintained on all four occasions at approximately 7.3 mmol/l by intravenous insulin. RESULTS: After subcutaneous Lispro injection, plasma free insulin (FIRI) was greater between 0 and 2 h (233 +/- 22 pmol/l) than after Hum-R (197 +/- 25 pmol/l) but lower between 2.25 and 7 h (81 +/- 10 vs. 104 +/- 13 pmol/l, P < 0.05). After Lispro, PG was lower versus Hum-R for 3 h (7.4 +/- 0.6 vs. 8.3 +/- 0.9 mmol/l) but subsequently increased more than after Hum-R (3.25-7h, 11.3 +/- 1 vs. 9.6 +/- 1.2 mmol/l), resulting in a 7-h postprandial PG greater than Hum-R (9.4 +/- 0.5 vs. 8.8 +/- 0.6 mmol/l) (all P < 0.05). Addition of NPH to Lispro increased the 2.5-to 7-h FIRI to 110 +/- 11 pmol/l and decreased the 3.25- to 7-h PG to 7.7 +/- 0.8 pmol/l, resulting in 0- to 7-h PG (7.3 +/- 0.3 mmol/l) lower than after Hum-R + NPH (7.9 +/- 0.5 pmol/l) (P < 0.05). CONCLUSIONS: At meals, in order for Lispro to improve postprandial blood glucose not only at 2-h, but also over a 7-h period in C-peptide-negative IDDM, basal insulin must be optimally replaced.

3-Hydroxybutyric Acid↗

Contribution of obesity to insulin resistance in noninsulin-dependent diabetes mellitus.

Inasmuch as previous studies have obtained conflicting results on the contribution of obesity to insulin resistance in noninsulin-dependent diabetes mellitus (NIDDM), we studied 10 nonobese and 10 obese NIDDM patients with the isoglycemic-(approximately 10 mmol/L)-hyperinsulinemic clamp (two insulin infusions of 4 and 40 mU/m-2 min-1), combined with [3-3H]glucose infusion and indirect calorimetry. As compared with nonobese patients, obese NIDDM patients had higher baseline peripheral and estimated portal plasma insulin concentrations (113 +/- 18 vs. 46 +/- 3 pmol/L and 288 +/- 53 vs. 98 +/- 6 pmol/L, respectively; P < 0.05) and less suppressed endogenous insulin production during clamp. Hepatic glucose production was greater in obese than in nonobese patients (basal, 16 +/- 1.1 vs. 12 +/- 0.5 mumol/kg-1 fat-free mass (FFM) min-1; clamp, 5.7 +/- 0.5 vs. 2.8 +/- 0.2 mumol/kg-1 FFM min-1, P < 0.05). Glucose utilization increased to a lesser extent in obese than in nonobese patients (49 +/- 5 vs. 73 +/- 7 mumol/kg-1 FFM min-1, P < 0.05) during clamp because of a lower increase in nonoxidative glucose metabolism (30 +/- 5 vs. 50 +/- 7 mumol/kg-1 FFM min-1, P < 0.05). Plasma free fatty acid concentrations and rates of lipid oxidation were greater in obese (P < 0.05) patients and correlated with hepatic glucose production (r = 0.79 and 0.50, P < 0.05). In conclusion, obesity exaggerates hepatic as well as extra-hepatic insulin resistance in NIDDM. The impaired inhibition of pancreatic beta-cell function by exogenous insulin contributes to exaggerated hyperinsulinemia in obese NIDDM.

Blood Glucose↗

Effects of recent, short-term hyperglycemia on responses to hypoglycemia in humans. Relevance to the pathogenesis of hypoglycemia unawareness and hyperglycemia-induced insulin resistance.

A single episode of recent hypoglycemia increases, whereas long-term hyperglycemia decreases, the glycemic thresholds of responses of counterregulatory hormone and symptoms to subsequent hypoglycemia in humans. To assess whether short-term, antecedent hyperglycemia exerts effects opposite to those observed after acute hypoglycemia, seven normal, nondiabetic subjects and eight insulin-dependent diabetes mellitus (IDDM) patients were studied during hyperinsulinemic-hypoglycemic clamp (sequential, 90-min plateaus of plasma glucose [PG] of 4.3, 3.7, 3.0, and 2.4 mmol/l). Nondiabetic subjects were studied the morning after either 6-h clamped hyperglycemia (PG approximately 13.5 mmol/l) or euglycemia (PG approximately 5 mmol/l) between 1600 and 2200 the previous day (glucose and insulin infused on both occasions), as well as after nocturnal hyperglycemia (PG approximately 13.5 mmol/l) or euglycemia between 2300 and 0500. The IDDM patients were studied after 15 h of euglycemia or hyperglycemia (approximately 17 mmol/l) but identical hyperinsulinemia (approximately 225 pmol/l) between 1600 and 0700. Neither PG thresholds of counterregulatory hormone, symptoms, onset of cognitive dysfunction to hypoglycemia, nor maximal responses were affected by antecedent, short-term hyperglycemia in normal nondiabetic subjects and IDDM patients (NS). However, the rate of glucose infusion required to maintain hypoglycemic plateaus during hypoglycemia was lower after hyperglycemia (nondiabetic subjects 31.2 +/- 3.4 vs. 36.7 +/- 4 mumol.kg-1.min-1, IDDM patients 33 +/- 3.1 vs. 42.5 +/- 3.9 mumol.kg-1.min-1; P < 0.05) indicating greater insulin resistance induced by antecedent hyperglycemia. In conclusion, in contrast to acute hypoglycemia and long-term hyperglycemia, recent, short-term hyperglycemia does not affect physiological responses to hypoglycemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Improved postprandial metabolic control after subcutaneous injection of a short-acting insulin analog in IDDM of short duration with residual pancreatic beta-cell function.

OBJECTIVE: To compare postprandial metabolic control after subcutaneous injection of a short-acting insulin analog [Lys(B289),Pro(B29)] (Lispro) or human regular insulin (Humulin R U-100 [Hum-R]) in insulin-dependent diabetes mellitus (IDDM) of short duration with residual beta-cell function. RESEARCH DESIGN AND METHODS: Six IDDM patients (age 25 +/- 2 years, diabetes duration 14 +/- 2 months, HbA1c 6.4 +/- 0.5%) with residual pancreatic beta-cell function (fasting plasma C-peptide 0.19 +/- 0.02 nmol/l) were studied on three different occasions. Postbreakfast plasma glucose was maintained at approximately 7.1 mmol/l by means of intravenous insulin until either 1200 when 0.1 U/kg Hum-R was injected or until 1225 when 0.1 U/kg of either Hum-R or Lispro was injected subcutaneously. Lunch (mixed meal, 692 Kcal) was served at 1230 (0 min). Six nondiabetic control subjects were also studied. RESULTS: After Lispro administration, the 120-min plasma glucose decreased more (6.1 +/- 0.3 mmol/l) than after injection of Hum-R at -30 min (7.7 +/- 0.3 mmol/l) or -5 min (9.9 +/- 0.2 mmol/l). By the end of the study, plasma glucose was still lower after Lispro was injected (6.7 +/- 0.3 mmol/l) than after Hum-R was injected at -30 min (7.6 +/- 0.3 mmol/l) or -5 min (7.3 +/- 0.2 mmol/l) (P < 0.05). Two IDDM patients required glucose to prevent hypoglycemia after being injected with Lispro, but four required glucose after being injected with Hum-R at -5 min (Lispro approximately 27 mmol glucose infused between 90 and 240 min; Hum-R approximately 80 mmol between 240 and 390 min). After Lispro, plasma insulin peaked earlier (at 30 min, 342 +/- 29 pmol/l) than after Hum-R injection at -30 min (at 90 min, 198 +/- 28 pmol/l) and was superimposable on that of nondiabetic subjects. In Hum-R injected at -5 min, plasma insulin peaked later (at 120 min) and subsequently remained greater than in the two other studies. CONCLUSIONS: Despite the lack of a time interval between injection and meal, Lispro controls postprandial plasma glucose concentration better than Hum-R given 30 min before meals and, to an even greater extent, better than Hum-R given 5 min before meals. In addition, Lispro minimizes the risk of postprandial hypoglycemia, thus closely mimicking the postprandial glucose homeostasis of nondiabetic subjects. IDDM patients with residual pancreatic beta-cell function are the ideal candidates for prandial use of Lispro because they can maintain near-normoglycemia longer after subcutaneous analog injection because of residual endogenous insulin secretion.

3-Hydroxybutyric Acid↗

Long-term recovery from unawareness, deficient counterregulation and lack of cognitive dysfunction during hypoglycaemia, following institution of rational, intensive insulin therapy in IDDM.

Hypoglycaemia unawareness, is a major risk factor for severe hypoglycaemia and a contraindication to the therapeutic goal of near-normoglycaemia in IDDM. We tested two hypotheses, first, that hypoglycaemia unawareness is reversible as long as hypoglycaemia is meticulously prevented by careful intensive insulin therapy in patients with short and long IDDM duration, and that such a result can be maintained long-term. Second, that intensive insulin therapy which strictly prevents hypoglycaemia, can maintain long-term near-normoglycaemia. We studied 21 IDDM patients with hypoglycaemia unawareness and frequent mild/severe hypoglycaemia episodes while on "conventional" insulin therapy, and 20 nondiabetic control subjects. Neuroendocrine and symptom responses, and deterioration in cognitive function were assessed in a stepped hypoglycaemia clamp before, and again after 2 weeks, 3 months and 1 year of either intensive insulin therapy which meticulously prevented hypoglycaemia (based on physiologic insulin replacement and continuous education, experimental group, EXP, n = 16), or maintenance of the original "conventional" therapy (control group, CON, n = 5). At entry to the study, all 21 IDDM-patients had subnormal neuroendocrine and symptom responses, and less deterioration of cognitive function during hypoglycaemia. After intensive insulin therapy in EXP, the frequency of hypoglycaemia decreased from 0.5 +/- 0.05 to 0.045 +/- 0.02 episodes/patient-day; HbA1c increased from 5.83 +/- 0.18 to 6.94 +/- 0.13% (range in non-diabetic subjects 3.8-5.5%) over a 1-year period; all counterregulatory hormone and symptom responses to hypoglycaemia improved between 2 weeks and 3 months with the exception of glucagon which improved at 1 year; and cognitive function deteriorated further as early as 2 weeks (p < 0.05). The improvement in responses was maintained at 1 year. The improvement in plasma adrenaline and symptom responses inversely correlated with IDDM duration. In contrast, in CON, neither frequency of hypoglycaemia, nor neuroendocrine responses to hypoglycaemia improved. Thus, meticulous prevention of hypoglycaemia by intensive insulin therapy reverses hypoglycaemia unawareness even in patients with long-term IDDM, and is compatible with long-term near-normoglycaemia. Because carefully conducted intensive insulin therapy reduces, not increases the frequency of moderate/severe hypoglycaemia, intensive insulin therapy should be extended to the majority of IDDM patients in whom it is desirable to prevent/delay the onset/progression of microvascular complications.

Adult↗

Relative roles of insulin and hypoglycaemia on induction of neuroendocrine responses to, symptoms of, and deterioration of cognitive function in hypoglycaemia in male and female humans.

To assess the relative roles of insulin and hypoglycaemia on induction of neuroendocrine responses, symptoms and deterioration of cognitive function (12 cognitive tests) during progressive decreases in plasma glucose, and to quantitate glycaemic thresholds, 22 normal, non-diabetic subjects (11 males, 11 females) were studied on four occasions: prolonged fast (n = 8, saline euglycaemia study, SA-EU), stepped hypoglycaemia (plasma glucose plateaus of 4.3, 3.7, 3 and 2.3 mmol/l) or euglycaemia during insulin infusion at 1 and 2 mU.kg-1.min-1 (n = 22, high-insulin hypoglycaemia and euglycaemia studies, HI-INS-HYPO and HI-INS-EU, respectively), and stepped hypoglycaemia during infusion of insulin at 0.35 mU.kg-1.min-1 (n = 9, low-insulin hypoglycaemia study, LO-INS-HYPO). Insulin per se (SA-EU vs HI-INS-EU), suppressed plasma glucagon (approximately 20%) and pancreatic polypeptide (approximately 30%), whereas it increased plasma noradrenaline (approximately 10%, p < 0.05). Hypoglycaemia per se (HI-INS-HYPO vs HI-INS-EU) induced responses of counterregulatory hormones (CR-HORM), symptoms and deteriorated cognitive function. With the exception of suppression of endogenous insulin secretion, which had the lowest glycaemic threshold of 4.44 +/- 0.06 mmol/l, pancreatic polypeptide, glucagon, growth hormone, adrenaline and cortisol had similar glycaemic thresholds (approximately 3.8-3.6 mmol/l); noradrenaline (3.1 +/- 0.0 mmol/l), autonomic (3.05 +/- 0.06 mmol/l) and neuroglycopenic (3.05 +/- 0.05 mmol/l) symptoms had higher thresholds. All 12 tests of cognitive function deteriorated at a glycaemic threshold of 2.45 +/- 0.06 mmol/l, but 7 out of 12 tests were already abnormal at a glycaemic threshold of 2.89 +/- 0.06 mmol/l. Although all CR-HORM had a similar glycaemic threshold, the lag time of response (the time required for a given parameter to increase) of glucagon (15 +/- 1 min) and growth hormone (14 +/- 3 min) was shorter than adrenaline (19 +/- 3 min) and cortisol (39 +/- 4 min) (p < 0.05). With the exception of glucagon (which was suppressed) and noradrenaline (which was stimulated), insulin per se (HI-INS-HYPO vs LO-INS-HYPO) did not affect the responses of CR-HORM, and did not influence the symptoms or the cognitive function during hypoglycaemia. Despite lower responses of glucagon, adrenaline and growth hormone (but not thresholds) in females than males, females were less insulin sensitive than males during stepped hypoglycaemia.

Adult↗

Pharmacokinetics, pharmacodynamics and glucose counterregulation following subcutaneous injection of the monomeric insulin analogue [Lys(B28),Pro(B29)] in IDDM.

The aim of these studies was to compare the pharmacokinetics, pharmacodynamics, counterregulatory hormone and symptom responses, as well as cognitive function during hypoglycaemia induced by s.c. injection of 0.15 IU/kg of regular human insulin (HI) and the monomeric insulin analogue [Lys(B28),Pro (B29)] (MI) in insulin-dependent-diabetic (IDDM) subjects. In these studies glucose was infused whenever needed to prevent decreases in plasma glucose below 3 mmol/l. After MI, plasma insulin increased earlier to a peak (60 vs 90 min) which was greater than after HI (294 +/- 24 vs 255 +/- 24 pmol/l), and plasma glucose decreased earlier to a 3 mmol/l plateau (60 vs 120 min) (p < 0.05). The amount of glucose infused to prevent plasma glucose falling below 3 mmol/l was approximately three times greater after MI than HI (293 +/- 26 vs 90 +/- 25 mumol.kg-1 x 60-375 min-1, p < 0.05). After MI, hepatic glucose production was more suppressed (0.7 +/- 1 vs 5.9 +/- 0.54 mumol.kg-1.min-1) and glucose utilization was less suppressed than after HI (11.6 +/- 0.65 vs 9.1 +/- 0.11 mumol.kg-1.min-1) (p < 0.05). Similarly, plasma NEFA, glycerol, and beta-OH-butyrate were more suppressed after MI than HI (p < 0.05), whereas plasma lactate increased only after MI, but not after HI. Responses of counterregulatory hormones, symptoms and deterioration in cognitive function during plasma glucose plateau of 3 mmol/l were superimposable after MI and HI (p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Post-hypoglycaemic hyperketonaemia does not contribute to brain metabolism during insulin-induced hypoglycaemia in humans.

It is controversial as to whether ketone bodies are utilized by the human brain as a fuel alternative to glucose during hypoglycaemia. To clarify the issue, we studied 10 normal volunteers during an experimental hypoglycaemia closely mimicking the clinical hypoglycaemia of patients with Type 1 (insulin-dependent) diabetes mellitus or insulinoma. Hypoglycaemia was induced by a continuous infusion of insulin (0.40 mU.kg-1.min-1 for 8 h, plasma insulin approximately 180 pmol/l) which decreased the plasma glucose concentration to approximately 3.1 mmol/l during the last 3 h of the studies. Subjects were studied on two occasions, i.e. spontaneous, counterregulatory-induced post-hypoglycaemic increase in 3-beta-hydroxybutyrate (from approximately 0.2 to approximately 1.1 mmol/l at 8 h), or prevention of post-hypoglycaemic hyperketonaemia (plasma beta-hydroxybutyrate approximately 0.1 mmol/l throughout the study) after administration of acipimox, a potent inhibitor of lipolysis. In the latter study, glucose was infused to match the hypoglycaemia observed in the former study. The glycaemic thresholds and overall responses of counterregulatory hormones, symptoms (both autonomic and neuroglycopenic), and deterioration of cognitive function (psychomotor tests) were superimposable in the control study in which ketones increased spontaneously after onset of hypoglycaemic counterregulation, as compared to the study in which ketones were suppressed (p = NS). The fact that responses of counterregulatory hormones, symptoms and deterioration in cognitive function were not exaggerated when posthypoglycaemic hyperketonaemia was prevented, indicate that during hypoglycaemia, the counterregulatory-induced endogenous hyperketonaemia does not provide the human brain with an alternative substrate to glucose. Thus, it is concluded that during hypoglycaemia, endogenous hyperketonaemia does not contribute to brain metabolism and function.

3-Hydroxybutyric Acid↗

Demonstration of a critical role for free fatty acids in mediating counterregulatory stimulation of gluconeogenesis and suppression of glucose utilization in humans.

In vitro studies indicate that FFA compete with glucose as an oxidative fuel in muscle and, in addition, stimulate gluconeogenesis in liver. During counterregulation of hypoglycemia, plasma FFA increase and this is associated with an increase in glucose production and a suppression of glucose utilization. To test the hypothesis that FFA mediate changes in glucose metabolism that occur during counterregulation, we examined the effects of acipimox, an inhibitor of lipolysis, on glucose production and utilization ([3-3H]glucose), and incorporation of [U-14C]-alanine into glucose during insulin-induced hypoglycemia. Eight normal volunteers were infused with insulin for 8 h to produce modest hypoglycemia (approximately 3 mM) on two occasions, first without acipimox (control) and then with acipimox administration (250 mg per os at 60 and 240 min). Despite identical plasma insulin concentrations, glucose had to be infused in the acipimox experiments (glucose-clamp technique) to maintain plasma glucose concentrations identical to those in control experiments. Acipimox completely prevented counterregulatory increases in lipolysis so that during the last 4 h plasma FFA were below baseline values and averaged 67 +/- 13 vs. 725 +/- 65 microM in control experiments, P < 0.001. Concomitantly, overall glucose production was reduced by 40% (5.5 +/- 11 vs. 9.3 +/- 0.7 mumol/kg per min, P < 0.001), and gluconeogenesis from alanine was reduced by nearly 70% (0.32 +/- 0.09 vs. 1.00 +/- 0.18 mumol/kg per min, P < 0.001), while glucose utilization increased by 15% (10.8 +/- 1.4 vs. 9.3 +/- 0.7 mumol/kg per min). We conclude that FFA play a critical role in mediating changes in glucose metabolism during counterregulation, and that under these conditions, FFA exert a much more profound effect on hepatic glucose production than on glucose utilization.

3-Hydroxybutyric Acid↗

Meticulous prevention of hypoglycemia normalizes the glycemic thresholds and magnitude of most of neuroendocrine responses to, symptoms of, and cognitive function during hypoglycemia in intensively treated patients with short-term IDDM.

To test the hypothesis that hypoglycemia unawareness is largely secondary to recurrent therapeutic hypoglycemia in IDDM, we assessed neuroendocrine and symptom responses and cognitive function in 8 patients with short-term IDDM (7 yr) and hypoglycemia unawareness. Patients were assessed during a stepped hypoglycemic clamp, before and after 2 wk and 3 mo of meticulous prevention of hypoglycemia, which resulted in a decreased frequency of hypoglycemia (0.49 +/- 0.05 to 0.045 +/- 0.03 episodes/patient-day) and an increase in HbA1c (5.8 +/- 0.3 to 6.9 +/- 0.2%) (P < 0.05). We also studied 12 nondiabetic volunteer subjects. At baseline, lower than normal symptom and neuroendocrine responses occurred at lower than normal plasma glucose, and cognitive function deteriorated only marginally during hypoglycemia. After 2 wk of hypoglycemia prevention, the magnitude of symptom and neuroendocrine responses (with the exception of glucagon and norepinephrine) nearly normalized, and cognitive function deteriorated at the same glycemic threshold and to the same extent as in nondiabetic volunteer subjects. At 3 mo, the glycemic thresholds of symptom and neuroendocrine responses normalized, and surprisingly, some of the responses of glucagon recovered. We concluded that hypoglycemia unawareness in IDDM is largely reversible and that intensive insulin therapy and a program of intensive education may substantially prevent hypoglycemia and at the same time maintain the glycemic targets of intensive insulin therapy, at least in patients with IDDM of short duration.

Adult↗

Mechanisms of arterial hypotension after therapeutic dose of subcutaneous insulin in diabetic autonomic neuropathy.

To assess whether a therapeutic, subcutaneous injection of insulin exerts hemodynamic effects in subjects with IDDM, 0.2 U/kg regular insulin was injected subcutaneously in 17 IDDM subjects: 6 without autonomic neuropathy, 7 with autonomic neuropathy and othostatic hypotension, and 4 with autonomic neuropathy but without orthostatic hypotension. Plasma glucose was maintained at approximately 8.5 mM throughout the studies. Mean blood pressure, plasma norepinephrine concentration, forearm vascular resistances, and calf venous volume were measured before and 120 min after subcutaneous insulin, in the supine position and 5 min after standing. Supine plasma volume ([125I]albumin and [131I]albumin) was measured before and after subcutaneous injection of insulin. In all three groups, subcutaneous insulin activated the sympathetic nervous system (approximately 30% increase in norepinephrine concentration). In subjects with IDDM but without autonomic neuropathy, standing forearm vascular resistance increased approximately 70% less after subcutaneous insulin, but supine or standing mean blood pressure did not decrease. In contrast, in subjects with IDDM with autonomic neuropathy and orthostatic hypotension, subcutaneous insulin decreased supine mean blood pressure (from 99 +/- 3 to 94 +/- 5 mmHg) and exaggerated the standing decrement in mean blood pressure (24 +/- 3 vs. 19 +/- 2 mmHg) (P < 0.05). This was associated with a decrease in forearm vascular resistance. Similarly, in subjects with IDDM with autonomic neuropathy without orthostatic hypotension, subcutaneously injected insulin decreased supine mean blood pressure (from 95 +/- 2 to 89 +/- 2 mmHg) and standing mean blood pressure by 8 +/- 1 mmHg (P < 0.05). Calf venous volume was not affected by subcutaneous insulin in any of the three groups. Plasma volume did not change after subcutaneous insulin in subjects with IDDM without autonomic neuropathy, whereas it decreased in those with autonomic neuropathy and orthostatic hypotension from 1.692 +/- 0.069 to 1.610 +/- 0.064 L/m2, without orthostatic hypotension from 1.631 +/- 0.027 to 1.593 +/- 0.024 L/m2, P < 0.05). No hemodynamic effects were observed when subjects with IDDM were restudied in a control experiment where placebo (distilled water), not insulin, was injected subcutaneously. In conclusion, therapeutic doses of subcutaneous insulin activate the sympathetic nervous system; decrease blood pressure in subjects with IDDM with autonomic neuropathy, but not in those without, primarily by decreasing arterial vascular resistances and plasma volume; and have no effects of capacitance vessels. Thus, in subjects with IDDM without autonomic neuropathy, greater activation of sympathetic nervous system after subcutaneous injection of insulin prevents orthostatic hypotension.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗