Physiological insulin replacement in type 1 diabetes mellitus

The DCCT and UKPDS studies have definitely established that in type 1 as well as in type 2 diabetes mellitus, long-term near-normoglycaemia strongly protects against onset and/or progression of microangiopathic complications. Therefore, implementation of insulin strategies to maintain long-term near-normoglycaemia is of key importance in the management of diabetes mellitus. To successfully reach the goal of near-normoglycaemia, insulin therapy has to be physiological, i.e. it has to mimic nature by providing a bolus of insulin at meal ingestion, and by replacing the need for basal insulin between meals and during the night. The meal-time insulin needs can be best met by s.c. injection of a short-acting insulin analogue (lispro, aspart). Short-acting insulin analogues should be preferred to human regular insulin for three main reasons. First, convenience (meal-time injection, better adaptation of insulin dose to carbohydrate content of the meal); second, lower blood glucose 2-hour after meals; third, less risk for late post-prandial hypoglycaemia. However, the benefits of meal-time treatment with short-acting insulin analogues become apparent only by the extent to which replacement of basal insulin is optimised as well. The interprandial (especially nocturnal) need for basal insulin can be best met by the continuous s.c. insulin infusion by an external minipump, the gold standard of basal insulin replacement. Continuous s.c. insulin infusion in the basal state is so good because it uses a short-acting insulin analogue (low variability in s.c. absorption, flat and peak-less action profile), not insulin preparations with retarded action (high variability of s.c. absorption, peak of action) likewise the model of multiple daily insulin injections. A second choice option is s.c. injection of an insulin preparation with retarded action. At present, the long-acting insulin analogue glargine is the retarded insulin preparation of choice because its action profile is flat, peakless and long-lasting (approximately 24 hours). This is in contrast with the peak action profile of NPH insulin which exhibits a short duration of action (10-15 h). Thus, the modern insulin strategies for intensive therapy always include use of a short-acting insulin analogue at meal-time, and use of either continuous s.c. insulin infusion, or a s.c. injection of insulin glargine to replace basal insulin. Insulin glargine reproduces closely the pharmacokinetics and pharmacodynamics of continuous s.c. insulin infusion, and should always be preferred to NPH in all insulin-requiring diabetic patients, both type 1 and type 2.

Intensive insulin treatment in diabetic children

Intensification of insulin therapy which maintains long-term near-normoglycaemia (HbA1c<7.0%) strongly protects against onset and/or progression of diabetic microangiopathy in Type 1 diabetes mellitus of adults. Similar intensification of insulin therapy is needed in diabetic children as well, in order to prevent complications a few years after diabetes onset, ie very often in young age. Provided adequate psychosocial support and education are available, children should be treated with multiple daily injections of insulin or, when necessary, with continuous subcutaneous insulin infusion, along with blood glucose monitoring. Insulin regimens may differ from child to child and vary from day to day in the same child, depending on lifestyle and considering all the available insulin preparations. These include the short-acting insulin (both human regular and short-acting insulin analogues), the intermediate-acting insulin (NPH and Lente), as well as the new long-acting insulin analogue glargine. The latter seems a promising candidate to substitute of basal insulin. The concern that intensified insulin therapy increases the risk of hypoglycaemia, as indicated by the Diabetes Control and Complications Trial (DCCT), is no longer tenable. On the contrary, a physiological, flexible insulin regimen better than a fixed insulin regimen, usually the twice daily split-mixed regimen, protects against the risk of hypoglycaemia in relation to food ingestion, physical exercise and sleep. Thus, appropriate education should be delivered at diabetes onset to the child and parents in order to start the strategy of intensified insulin therapy as early as possible.

Insulins today and beyond

The advent of insulin almost 80 years ago revolutionised treatment of diabetes and must be one of the most outstanding achievements of twentieth century medicine. Since then, there has been an ever-increasing awareness and acceptance of the need to achieve and sustain near-normoglycaemia to delay onset and retard progression of diabetic angiopathy. Physiological insulin replacement is therefore central to management of patients with diabetes who are unable to make [corrected] insulin. Insulin formulations, treatment strategies, and methods and routes of delivery have changed much, with more and more options for monitoring the effect on blood glucose concentrations. Patients with type 1 and type 2 diabetes need insulin much more aggressively than previously. Parallel developments in glucose-sensing technologies are welcomed as an integral part of safe and optimum implementation of insulin replacement therapy.

Pharmacokinetics and pharmacodynamics of subcutaneous injection of long-acting human insulin analog glargine, NPH insulin, and ultralente human insulin and continuous subcutaneous infusion of insulin lispro

To compare the pharmacokinetics/dynamics of the long-acting insulin analog glargine with NPH, ultralente, and continuous subcutaneous (SC) infusion of insulin lispro (continuous subcutaneous insulin infusion [CSII]), 20 C-peptide-negative type 1 diabetic patients were studied on four occasions during an isoglycemic 24-h clamp. Patients received SC injection of either 0.3 U/kg glargine or NPH insulin (random sequence, crossover design). On two subsequent occasions, they received either an SC injection of ultralente (0.3 U/kg) or CSII (0.3 U x kg(-1) x 24 h(-1)) (random sequence, crossover design). After SC insulin injection or CSII, intravenous (IV) insulin was tapered, and glucose was infused to clamp plasma glucose at 130 mg/dl for 24 h. Onset of action (defined as reduction of IV insulin >50%) was earlier with NPH (0.8 +/- 0.2 h), CSII (0.5 +/- 0.1 h), and ultralente (1 +/- 0.2 h) versus glargine (1.5 +/- 0.3 h) (P < 0.05) (mean +/- SE). End of action (defined as an increase in plasma glucose >150 mg/dl) occurred later with glargine (22 +/- 4 h) than with NPH (14 +/- 3 h) (P < 0.05) but was similar with ultralente (20 +/- 6 h). NPH and ultralente exhibited a peak concentration and action (at 4.5 +/- 0.5 and 10.1 +/- 1 h, respectively) followed by waning, whereas glargine had no peak but had a flat concentration/action profile mimicking CSII. Interindividual variability (calculated as differences in SD of plasma insulin concentrations and glucose infusion rates in different treatments) was lower with glargine than with NPH and ultralente (P < 0.05) but was similar with glargine and CSII (NS). In conclusion, NPH and ultralente are both peak insulins. Duration of action of ultralente is greater, but intersubject variability is also greater than that of NPH. Glargine is a peakless insulin, it lasts nearly 24 h, it has lower intersubject variability than NPH and ultralente, and it closely mimics CSII, the gold standard of basal insulin replacement.

Enhanced stimulation of glucose uptake by insulin increases exercise-stimulated glucose uptake in skeletal muscle in humans: studies using [15O]O2, [15O]H2O, [18F]fluoro-deoxy-glucose, and positron emission tomography

In vitro studies have shown that insulin and exercise stimulate glucose uptake in part via distinct mechanisms. We determined whether a high rate of insulin-stimulated glucose uptake (good insulin sensitivity) is associated with an enhanced ability of exercise to increase glucose uptake in vivo in humans. In our study, 22 normal subjects performed one-legged isometric exercise for 105 min (45-150 min) under intravenously maintained euglycemic-hyperinsulinemic conditions (0-150 min). Rates of oxygen consumption, blood flow, and glucose uptake were quantitated simultaneously in skeletal muscle of both legs using [15O]O2, [15O]H2O, [18F]fluoro-deoxy-glucose, and positron emission tomography. The one-legged exercise, performed at an intensity of 11% of maximal isometric force, was designed to induce similar increases in oxygen consumption in both groups. In the entire group, exercise increased oxygen consumption from 2.3 +/- 0.3 ml x kg(-1) muscle x min(-1) (insulin) to 34.2 +/- 3. ml x kg(-1) muscle x min(-1) (insulin and exercise) (P < 0.001) and muscle glucose uptake from 60 +/- 6 pmol x kg(-1) muscle x min(-1) (insulin) to 220 +/- 22 micromol x kg(-1) muscle x min(-1) (insulin and exercise) (P < 0.001). The exercise-induced increase in glucose uptake was due to marked increases in blood flow (36 +/- 5 ml x kg(-1) muscle x min(-1) [insulin] vs. 262 +/- 20 ml x kg(-1) muscle x min(-1) [insulin and exercise], P < 0.001) rather than glucose extraction, which decreased from 2.0 +/- 0.2 mmol/l (insulin) to 1.0 +/- 0.1 mmol/1 (insulin and exercise) (P < 0.001). The subjects were classified according to their mean rate of whole-body insulin-stimulated glucose uptake into those with high (49 +/- 3 micromol x kg(-1) x min(-1)) and normal (27 +/- 2 micromol x kg(-1) x min(-1)) rates of insulin-stimulated glucose uptake. Both insulin-stimulated (2.4 +/- 1.1 vs. 2.3 +/- 1.2 ml x kg(-1) muscle x min(-1), normal vs. high insulin sensitivity) and exercise- and insulin-stimulated (33 +/- 6 vs. 34 +/- 4 ml x kg(-1) muscle x min(-1)) rates of oxygen consumption were comparable between the groups. Exercise increased glucose uptake more in the group with high insulin sensitivity (195 +/- 25 pmol x kg(-1) muscle x min(-1)) than in the group with normal insulin sensitivity (125 +/- 19 micromol x kg(-1) muscle x min(-1)) (P < 0.05). Muscle blood flow was closely correlated with the rate of oxygen consumption (r = 0.91, P < 0.0001), and insulin-stimulated (30 +/- 5 vs. 35 +/- 6 ml x kg(-1) muscle x min(-1)) and exercise-induced increments (222 +/- 31 vs. 228 +/- 23 ml x kg(-1) muscle x min(-1)) in muscle blood flow were similar between the groups. Glucose extraction remained higher in the group with high insulin sensitivity (1.2 +/- 0.2 mmol/l) than in the group with normal insulin sensitivity (0.7 +/- 0.1 mmol/l, P < 0.05). We conclude that whereas acute exercise per se increases glucose uptake via increasing glucose delivery, good insulin sensitivity modulates exercise-induced increases in glucose uptake by enhancing cellular glucose extraction.

Autoantibody recognition of COOH-terminal epitopes of GAD65 marks the risk for insulin requirement in adult-onset diabetes mellitus

Some type 2 diabetic subjects develop secondary failure to sulphonylurea treatment and require insulin therapy. To test the diagnostic sensitivity and specificity of epitopes of GAD65 autoantibodies (GAD65Ab) for insulin requirement, in patients with latent autoimmune diabetes of the adult, we studied 569 adult subjects with a clinical diagnosis of type 2 diabetes mellitus. All the patients had been initially treated with hypoglycemic agents and/or diet for at least 1 yr. The presence of GAD65Ab (61/569, 10.7%) depended on insulin therapy (P<0.0001), low BMI (P<0.0001), and low basal C-peptide (P = 0.01). The majority of GAD65Ab-positive subjects (47/61, 77%) had antibodies directed to both middle (GAD65-MAb) and COOH-terminal (GAD65-CAb) epitopes. However, GAD65-CAb were more frequent in insulin-treated subjects (92% of GAD65Ab+ individuals) than in subjects treated with hypoglycemic agents and/or diet (18.2% of GAD65Ab+ individuals), while the exclusive presence of GAD65-MAb was more frequent in subjects treated with hypoglycemic agents and/or diet (81.8% vs. 8%) (P<0.0001). The presence of GAD65-CAb had a diagnostic specificity for insulin requirement as high as 99.4% (compared with 96.9% of GAD65Ab as measured in the traditional radiobinding assay) and identified a subgroup of patients with low BMI, low basal C-peptide values, and a need for insulin therapy. Subjects carrying only GAD65-MAb were phenotypically indistinguishable from GAD65Ab-negative patients. Patients positive for GAD65-M+CAb, but not those positive for GAD65-MAb only, showed an increased risk for thyroid autoimmunity, as revealed by the presence of thyroid peroxidase autoantibodies. Our study demonstrates that the use of epitope-specific antibody assays improves the diagnostic specificity of GAD65Ab, and that the presence of GAD65Ab binding to COOH-terminal epitopes is strongly associated with a need for insulin requirement.

Physiology of glucose counterregulation to hypoglycemia

Prevention of hypoglycemia is essential for the preservation of brain metabolism and survival of the whole body. Normally, glucose is the only substrate used by the brain to meet its metabolic requirements. Therefore, a continuous supply of circulatory glucose is a necessary prerequisite for normal cerebral metabolism. When plasma glucose concentration decreases (e.g., during prolonged fasting or after administration of glucose-lowering drugs) several physiologic responses are activated to prevent further decreases in blood glucose. The first response is known as counterregulation, a system that prevents and corrects hypoglycemia through the release of counterregulatory hormones.

Contribution of postprandial versus interprandial blood glucose to HbA1c in type 1 diabetes on physiologic intensive therapy with lispro insulin at mealtime

OBJECTIVE

To quantitate the contribution of postprandial blood glucose, which improves with the short-acting insulin analog lispro [Lys(B28),Pro(B29)] in type 1 diabetes, to the overall 24-h blood glucose concentration and the long-term HbA1c concentration under conditions of different postabsorptive blood glucose.

RESEARCH DESIGN AND METHODS

A total of 24 type 1 diabetic patients on long-term intensive therapy with premeal human regular insulin (Hum-R) and bedtime NPH were randomly assigned to a continuation of Hum-R (group 1, n = 8), lispro (group 2, n = 8), or lispro + NPH (in variable proportions) administered at mealtime (group 3, n = 8) for 3 months, NPH administered at bedtime was continued in all three groups. Data from home blood glucose monitoring were collected, and a 24-h plasma glucose and insulin profile was obtained during a 2-day hospital visit to calculate areas under the postprandial glucose curve (3.5 h after breakfast, 3.5 h after lunch, and 3.0 h after dinner for a total of 10.0 h) and the postabsorptive blood glucose curve (the remaining 14.0 h out of 24.0 h) (AUC). Eight nondiabetic subjects were also studied.

RESULTS

The substitution of Hum-R with lispro (group 2) resulted in lower postprandial blood glucose, but greater postabsorptive blood glucose (P < 0.05 vs. group 1). The postprandial blood glucose AUC was lower (161 +/- 19 vs. 167 +/- 20 mg.100 ml-1.h-1), but the postabsorptive blood glucose AUC was greater (155 +/- 22 vs. 142 +/- 19 mg.100 ml-1.h-1) (P < 0.05). Therefore, the 24-h blood glucose AUC was no different (NS). Consequently, HbA1c was no different (NS). This occurred because in group 2, mealtime lispro resulted in normal prandial plasma insulin, but also resulted in lower interprandial concentration (P < 0.05 vs. group 1). When NPH was added to lispro (30% at breakfast, 40% at lunch, 10% at dinner) in group 3, postabsorptive plasma insulin was similar to group 1 (NS), in group 3, the postprandial blood glucose AUC (153 +/- 17 mg.100 ml-1.h-1) was lower and the postabsorptive blood glucose AUC was no different, as compared with group 1 (NS). Therefore, the 24-h blood glucose AUC was lower (147 +/- 17 vs. 155 +/- 21 and 158 +/- 20 mg.100 ml-1.h-1), and HbA1c was lower (6.41 +/- 0.12 vs. 6.84 +/- 0.2 and 6.96 +/- 0.2% (groups 3, 1, and 2 respectively, P < 0.05). Frequency of hypoglycemia was greater in group 2 (P < 0.05), but not in group 3 (NS) vs. group 1.

How to ameliorate the problem of hypoglycemia in intensive as well as nonintensive treatment of type 1 diabetes

Maintenance of long-term near-normoglycemia by intensive therapy largely, if not fully, prevents the onset of microangiopathic complications and delays progression of complications in type 1 diabetic patients. However, intensive therapy has been reported to increase the frequency of severe hypoglycemia. In addition, a number of experimental studies have shown that a few episodes of mild, recurrent hypoglycemia blunt the symptom and hormonal responses to hypoglycemia over the next few days. At present, the critical "post-DCCT" (Diabetes Control and Complications Trial) questions are: is it possible to maintain long-term HbA1c < 7.0%, first, without increasing the frequency of severe hypoglycemia, and second, without increasing the frequency of mild, recurrent hypoglycemia? The answer is yes. The key factors are use of a physiological model of insulin replacement and the education of patients to appropriate the decision of insulin dose based on blood glucose monitoring and eating patterns. Hypoglycemia unawareness should be suspected whenever HbA1c is < 6.0 (upper normal limit 5.5%) and the patient does not report autonomic symptoms when their blood glucose level is < 3.0 mmol/l. The unaware patients should be treated with a short-term program of meticulous prevention of hypoglycemia, which reverses the abnormalities of responses of symptoms, hormonal counterregulation, and brain cognitive function. In turn, reversal of these abnormalities decreases the risk for severe hypoglycemia. Importantly, a program of meticulous prevention of hypoglycemia does not result in loss of long-term near-normoglycemia, i.e., it is compatible with the glycemic targets of intensive therapy.

Long-term intensive treatment of type 1 diabetes with the short-acting insulin analog lispro in variable combination with NPH insulin at mealtime

OBJECTIVE

To establish whether the short-acting insulin analog lispro can be successfully implemented in long-term intensive insulin therapy in type 1 diabetes, and if so, what its effects are on glycemic control and frequency and awareness of hypoglycemia.

RESEARCH DESIGN AND METHODS

We randomized 56 type 1 diabetic patients to treatment with either lispro (n = 28) or human regular insulin (Hum-R; n = 28) as mealtime insulin for 1 year (open design, parallel groups). Lispro was injected at mealtime and Hum-R was given 10-40 min before meals (bedtime NPH was continued on both occasions). With lispro, NPH was added at breakfast (approximately 70/30), lunch (approximately 60/40), and supper (approximately 80/20) (mixing percentage of lispro/NPH) to optimize premeal and bedtime blood glucose.

RESULTS

Total daily insulin units were no different in the two treatment groups, but with lispro approximately 30% less short-acting insulin at meals and approximately 30% more NPH was needed versus Hum-R (P < 0.05). The bedtime NPH dosage was no different. With lispro + NPH, the mean daily blood glucose was lower than with Hum-R (8.0 +/- 0.1 vs. 8.8 +/- 0.1 mmol/l; P < 0.05), HbA1c was lower (6.34 +/- 0.10 vs. 6.71 +/- 0.11%, mean value over 1 year; P < 0.002), and hypoglycemia (blood glucose < or = 3.8 mmol/l) was less frequent (7.4 +/- 0.5 vs. 11.5 +/- 0.7 episodes/patient-month) and tended to occur more within 90 min after meals than in the postabsorptive state (P < 0.05 vs. Hum-R). After 1 year, plasma adrenaline and symptom responses to experimental, stepped hypoglycemia improved with lispro and were closer to the responses of 12 nondiabetic control subjects versus Hum-R both in terms of thresholds and magnitude (P < 0.05).

CONCLUSIONS

We concluded that mealtime injection of lispro + NPH improves the 24-h blood glucose and the percentage HbA1c as compared with Hum-R. The improvement can be maintained long term. Intensive therapy with lispro + NPH results in less frequent hypoglycemia and better awareness and counterregulation of hypoglycemia.

Gender differences in basal protein kinetics in young adults

Gender affects energy expenditure and influences the relative utilization of carbohydrate and fat as fuels. However, little is known about the possible effects of gender on protein metabolism. Thus, we compared whole body and plasma (albumin and fibrinogen) protein kinetics in the basal postabsorptive state in young, untrained volunteers divided into two groups according to gender (women: n=17; age, 24+/-4 yr; men: n=17; age, 25+/-2 yr). The two groups were matched for body mass index. Protein kinetics were measured by means of L-[1-14C]leucine infusion. The leucine whole body rate of appearance, an index of proteolysis, and nonoxidative rate of disappearance, an index of protein synthesis, were similar in the two groups. However, the leucine oxidation rate was significantly lower in women compared to men (0.23+/-0.07 vs. 0.31+/-0.08 micromol/kg min; P=0.0062). Similar results were obtained when data were adjusted for estimated body composition. Albumin and fibrinogen fractional secretion rates were not different in the two groups. In conclusion, in the basal state leucine oxidation is lower in women than in men regardless of body composition. This could be one of the factors contributing to the lower metabolic rate in women.

Prevention and treatment of hypoglycaemia unawareness in type 1 diabetes mellitus

Unawareness of hypoglycaemia (reduced ability/failure to recognize hypoglycaemia symptoms at the physiological threshold of 3.0 mmol/l) occurs frequently in type 1 diabetes mellitus, and patients are then at risk for severe hypoglycaemia. Unawareness of hypoglycaemia is the result of earlier frequent episodes of hypoglycaemia (iatrogenic). Likewise, a history of hypoglycaemia induces unawareness, while meticulous prevention of hypoglycaemia can reverse hypoglycaemia unawareness. Therefore, it is essential that insulin therapy regimens for type 1 diabetes mellitus be designed not only to maintain near-normoglycaemia, but also to minimize hypoglycaemia. Such a goal is feasible as long as (1) a rational plan of insulin therapy is adopted, including appropriate use of the short-acting insulin analogue lispro, (2) blood glucose is properly monitored, (3) blood glucose targets are individualized, and (4) education programs are widely implemented.

Use of the short-acting insulin analogue lispro in intensive treatment of type 1 diabetes mellitus: importance of appropriate replacement of basal insulin and time-interval injection-meal

To establish whether lispro may be a suitable short-acting insulin preparation for meals in intensive treatment of Type 1 diabetes mellitus (DM) in patients already in chronic good glycaemic control with conventional insulins, 69 patients on intensive therapy (4 daily s.c. insulin injections, soluble at each meal, NPH at bedtime, HbA1c <7.5%) were studied with an open, cross-over design for two periods of 3 months each (lispro or soluble). The % HbA1c and frequency of hypoglycaemia were assessed under four different conditions (Groups I-IV). Lispro was always injected at mealtime, soluble 10-40 min prior to meals (with the exception of Group IV). Bedtime NPH was continued with both treatments. When lispro replaced soluble with no increase in number of daily NPH injections (Group I, n = 15), HbA1c was no different (p = NS), but frequency of hypoglycaemia was greater (p < 0.05). When NPH was given 3-4 times daily, lispro (Group II, n = 18), but not soluble (Group III, n = 12) decreased HbA1c by 0.35 +/- 0.25% with no increase in hypoglycaemia. When soluble was injected at mealtimes, HbA1c increased by 0.18 +/- 0.15% and hypoglycaemia was more frequent than when soluble was injected 10-40 min prior to meals (Group IV, n = 24) (p < 0.05). It is concluded that in intensive management of Type 1 DM, lispro is superior to soluble in terms of reduction of % HbA1c and frequency of hypoglycaemia, especially for those patients who do not use a time interval between insulin injection and meal. However, these goals cannot be achieved without optimization of basal insulin.

Counterregulatory mechanisms to insulin-induced hypoglycemia in humans: relevance to the problem of intensive treatment of IDDM

Hypoglycemia unawareness is a condition of decreased/absent perception of specific symptoms which normally inform the subject that plasma glucose is decreasing to dangerous levels resulting in neuroglycopenia. This syndrome is frequent in IDDM. In the absence of warning symptoms, IDDM patients cannot take any measure (e.g. eating) to prevent severe neuroglycopenia (unconsciousness). Because hypoglycemia unawareness is associated with impaired glucose counterregulation, especially reduced adrenaline responses, hypoglycemia unawareness is a risky condition for severe hypoglycemia. A number of studies in animals and humans indicate that hypoglycemia unawareness is largely, if not fully, secondary to recurrent or chronic hypoglycemia. Meticulous prevention of hypoglycemia in IDDM largely recovers the symptoms of hypoglycemia and the responses of adrenaline. It is important that diabetologists and IDDM patients are familiar with the syndrome of hypoglycemia unawareness and learn how to prevent/treat it in programs of intensive therapy. Intensive therapy aiming strictly at normoglycemia may increase the frequency of hypoglycemia and hypoglycemia unawareness. On the other hand, if intensive therapy is combined with a program of prevention of hypoglycemia, the percentage of HbA1c can be maintained long-term below 7.0% (i.e. below values risky for onset/progression of complications), and at the same time the frequency of hypoglycemia is very low. Under these conditions, IDDM patients maintain the awareness of warning symptoms and adrenaline response to hypoglycemia, a vital back-up system for the safety of intensive therapy of IDDM.

Moderate and large doses of ethanol differentially affect hepatic protein metabolism in humans

The intake of approximately 70 g of alcohol impairs liver protein metabolism in healthy humans. To establish the threshold at which alcohol impairs hepatic protein metabolism in humans we compared the effects of 500 mL of water (control study), 300 (28.4 g ethanol) or 750 mL (71 g ethanol) of table wine on hepatic protein metabolism in three groups of healthy nonalcoholic volunteers. Hepatic protein metabolism was estimated (L-[1-14C]leucine infusion) by measuring the fractional secretory rates of albumin and fibrinogen during the overnight postabsorptive state (basal) and the subsequent administration of water or two different amounts of wine (300 or 750 mL) given with a liquid glucose-lipid-amino acid meal. During the meal, water did not affect fibrinogen fractional secretory rate and increased albumin fractional secretory rate by approximately 50% (P < 0.01). The 300 mL of wine increased albumin secretory rate by only approximately 20% (P < 0.01 vs. basal, P < 0.04 vs. water) and did not affect fibrinogen secretory rate. The 750 mL of wine profoundly impaired hepatic protein metabolism, decreasing the fractional secretory rates of albumin (P < 0.01 vs. water and 300 mL wine) and fibrinogen (P < 0.04 vs. water and 300 mL of wine) below the postabsorptive values. These results demonstrate that a moderate dose of alcohol (28 g, approximately 2 drinks) slightly affects postprandial hepatic protein metabolism by blunting the meal-induced increase in albumin synthesis, whereas it does not interfere with fibrinogen synthesis as do higher doses.

Nicotinamide counteracts alcohol-induced impairment of hepatic protein metabolism in humans

We have recently shown that a large amount of wine (750 mL, approximately 70 g of alcohol) markedly impairs postprandial hepatic protein metabolism in healthy subjects. This is probably due to the shift in the intracellular redox state (increased NADH/NAD+) induced by ethanol oxidation. If this hypothesis is true, the administration of nicotinamide (NAD+ precursor) should provide NAD+ in excess and thus correct the NADH/NAD+ abnormalities and prevent the ethanol hepatotoxicity. Whole-body protein metabolism and the fractional secretory rates of hepatic (albumin, fibrinogen) and extra-hepatic (immunoglobulin G, IgG) plasma proteins were measured in the basal postabsorptive and in the absorptive states in 15 healthy subjects, that had been assigned to three groups matched for age and body mass index. During the absorptive state (intragastric meal), the three groups received water (control), 750 mL of wine, or 750 mL of wine + 1.25 g of nicotinamide, respectively. The redox state was estimated by determining the plasma lactate/pyruvate ratio. Compared with the basal state, wine alone increased the lactate/pyruvate ratio twofold and depressed the fractional secretory rates of albumin and fibrinogen (P < 0.01 vs. control and nicotinamide); nicotinamide reduced the effects of wine on the lactate/pyruvate ratio (P < 0.02 vs. wine alone) and prevented the reduction of albumin and fibrinogen secretory rates (P > 0.05 vs. control). These results indicate that nicotinamide counteracts the acute hepatotoxic effects of ethanol by ameliorating the redox state.

Hypoglycaemia unawareness

Hypoglycaemia unawareness, a frequent syndrome in insulin-dependent diabetes mellitus (IDDM), involves a decrease or absence of perception of specific symptoms which normally inform the subject that plasma glucose is decreasing to dangerous levels leading to neuroglycopenia. Without warning symptoms, IDDM patients are unable to take measures (e.g. eating) to prevent severe neuroglycopenia (unconsciousness). As hypoglycaemia unawareness is associated with impaired glucose counterregulation, especially reduced adrenaline responses, it can lead to severe hypoglycaemia. Various studies in animals and humans have indicated that hypoglycaemia unawareness is largely, if not entirely, secondary to increased brain glucose transport due to recurrent or chronic hypoglycaemia. In fact, meticulous prevention of hypoglycaemia largely restores the warning symptoms and adrenaline responses, at least in short-term IDDM. In long-term IDDM, recovery is less complete. Diabetologists and IDDM patients need to be familiar with hypoglycaemia unawareness and how to prevent or treat it. Intensive therapy strictly for normoglycaemia may actually increase the frequency of hypoglycaemia and hypoglycaemia unawareness. However, if intensive therapy is combined with a hypoglycaemia prevention programme, the percentage of HbA1c can be maintained below risk values for the onset or progression of complications, and the frequency of hypoglycaemia can be kept low. Under these conditions, IDDM patients can maintain the warning symptoms and adrenaline response to hypoglycaemia, ensuring a vital backup system for safe intensive therapy of IDDM.

Strategies toward improved control during insulin lispro therapy in IDDM. Importance of basal insulin

OBJECTIVE

To examine whether overall glycemic control can be improved with insulin lispro by adjustment of the basal insulin regimen without an increased risk of hypoglycemia.

RESEARCH DESIGN AND METHODS

A 5-month open study was performed in 66 IDDM patients after they had been transferred from human regular insulin to insulin lispro as a premeal therapy. The premeal and basal insulin regimens were adjusted according to self-monitoring of blood glucose during the visits at 2-week to 1-month intervals. Diurnal glucose profile, hypoglycemic events, HbA1c, and patient satisfaction were evaluated.

RESULTS

The mean daily glucose level decreased from 9.2 +/- 0.2 to 8.4 +/- 0.2 mmol/l (P = 0.001) and HbA1c decreased from 8.8 +/- 0.1 to 8.0 +/- 0.1% (P < 0.001) (mean +/- SD). The number of daily NPH injections increased from 1.4 +/- 0.1 at baseline to 3.1 +/- 0.1 at the end of the study. Total daily insulin dose increased by 3 U (7%) because of an 8-U (43%) rise in basal insulin, whereas premeal insulin dose decreased by 5 U (20%). The number of hypoglycemic episodes did not change during the study. Of the patients, 86% considered insulin lispro equal or better than human regular insulin.

CONCLUSIONS

Although the study was open, the date suggest that the appropriate combination of insulin lispro and basal insulin can improve postmeal hyperglycemia, HbA1c, and treatment satisfaction without increasing the risk of hypoglycemia.