Silybin-beta-cyclodextrin in the treatment of patients with diabetes mellitus and alcoholic liver disease. Efficacy study of a new preparation of an anti-oxidant agent.

BACKGROUND AND AIMS: In patients with non-insulin dependent diabetes mellitus (T2DM) and associated chronic liver disease, plasma levels of glucose, insulin and triglycerides are high, lipid peroxidation is increased and natural antioxidant reserves are reduced. Thus, we hypothesised that the re-balancing of cell redox levels and amelioration of liver function could result in a better glucose and lipid metabolism. To study this, we assessed the effect of a new oral formulation of an antioxidant agent - silybin-beta-cyclodextrin (named IBI/S) - in patients with chronic alcoholic liver disease and concomitant T2DM. METHODS: Sixty outpatients were enrolled in a three-centre, double blind, randomised, IBI/S vs placebo study. Forty-two (21 in the group IBI/S - 135 mg/d silybin per os - and 21 in the placebo group) concluded the 6-month treatment period. The efficacy parameters included fasting and mean daily plasma glucose levels, glycosylated hemoglobin (HbA1c), basal, stimulated C-peptide and insulin levels, total-, HDL-cholesterol and triglycerides levels in addition to conventional liver function tests. Insulin sensitivity was estimated by HOMA-IR. Malondialdehyde (MDA) was also measured before and after treatment as an index of oxidative stress. RESULTS: Fasting blood glucose levels, which were similar at baseline in IBI/S group and in the placebo group (173.9 mg/dl and 177.1 mg/dl, respectively), decreased to 148.4 mg/dl (-14.7% vs baseline; p = 0.03) in the IBI/S group while they were virtually unchanged in the placebo group. The comparison between the groups at mo 6 (T6) also showed a significant reduction of glucose levels in the IBI/S group (p = 0.03). The same trend was observed in mean daily blood glucose levels, HbA1c and HOMA-IR, although differences were not significant. Basal and stimulated C-peptide values showed that only a few changes had occured in both groups. Such results indicate that insulin secretion was virtually unaffected, as confirmed also by the insulinemia data. Plasma triglycerides concentrations dropped from a baseline value of 186 mg/dl to 111 mg/dl (T6) in the IBI/S group, with significant differences at all instances with respect to baseline values. By contrast, triglycerides increased from 159 mg/dl at entry to 185 mg/dl (T6) in the placebo group. The difference between the groups at T6 was highly significant (p < 0.01). Total and HDL cholesterol as well as liver function tests did not change significantly during the study in both groups. MDA decreased significantly only in the group receiving IBI/S. No clinically relevant side effects were observed in either group. CONCLUSIONS: Oral administration silybin-beta-cyclodextrin in patients with T2DM and compensated chronic alcoholic liver disease causes a significant decrease in both glucose and triglyceride plasma levels. These effects may be due to the recovery of energy substrates, consistent with a reduced lipid peroxidation and an improved insulin activity.

Cardiovascular mortality in non-insulin-dependent diabetes mellitus. A controlled study among 683 diabetics and 683 age- and sex-matched normal subjects.

Although non-insulin-dependent diabetes mellitus (NIDDM) is considered a major cause of death, the role of some independent risk factors in diabetic patients is under debate. In fact the prognosis of NIDDM diabetes varies considerably in relation to the individual risk pattern, and the different studies are not directly comparable because of differences in size, age and geography of the samples, and type of statistical analysis. The aim of the study is to identify the independent predictors of mortality in a cohort of subjects with NIDDM, and to verify whether the relative risk (RR) of cardiovascular mortality is different in comparison to that of coeval non-diabetic subjects from a general population. The study includes 683 patients with NIDDM from the Northern Italian town of Pordenone, followed up for 6 years and age- and sex-matched to 683 non-diabetic subjects from a Northern Italian general population. When the two cohorts were compared, NIDDM turned out to be a strong risk factor for cardiovascular mortality (RR: 2.67). Age, coronary artery disease (RR: 1.78), arterial hypertension (RR: 1.39), macro- (RR: 2.97) and microalbuminuria (RR: 2.01) were independent predictors of cardiovascular mortality in the diabetics. In conclusion, survival of diabetic patients is worse than that of non-diabetic coeval subjects. Only few items are able to predict cardiovascular mortality in the diabetics, namely age, hypertension, CAD, macro- and microalbuminuria.

Cryoglobulinaemic membranoproliferative glomerulonephritis and hepatitis C virus infection.

BACKGROUND/AIM: A striking correlation between mixed cryoglobulinaemia and chronic hepatitis C virus infection has recently been described. Since membrano-proliferative glomerulonephritis is a rare complication of mixed cryoglobulinaemia, this study was undertaken to determine the prevalence of Hepatitis C virus infection in membrano-proliferative glomerulonephritis. PATIENTS: Eighteen patients, selected among a group of 121 affected by mixed cryoglobulinaemia, with renal involvement were included in the present study. A group of 148 patients affected by renal disease of different aetiology and the general population (6,917 people) were used as control groups. METHODS: The presence of anti-hepatitis C virus antibodies was determined by a commercial kit. The hepatitis C virus genotype was determined according to Okamoto. All patients underwent kidney and bone marrow biopsy, while the hepatic biopsy was performed in those showing signs of chronic liver disease. RESULTS: In patients with renal involvement, the kidney biopsy showed the presence of membrano-proliferative glomerulonephritis Type I in all cases. Chronic liver disease was present in eleven patients (61%). All patients were positive for serum hepatitis C virus-RNA. Bone marrow biopsy was normal in five cases, while in the others paratrabecular foci of infiltration by small lymphocytes were present. In six of these, the massive bone marrow infiltration by lymphoplas-macytoid lymphocytes suggested the diagnosis of low grade non-Hodgkin's lymphoma. In the group of patients affected by other chronic renal disease, the prevalence of hepatitis C virus infection (3.1%) was not different from that of the general population (3.2%). CONCLUSIONS: Hepatitis C virus seems to be the aetiologic agent of mixed cryoglobulinaemia and, consequently, of membrano-proliferative glomerulonephritis.

Systemic manifestations and liver disease in patients with chronic hepatitis C and type II or III mixed cryoglobulinaemia.

The aim of this study was to evaluate the prevalence of cryoglobulins in patients with chronic hepatitis B and C virus infection and to investigate the association of type II and type III mixed cryoglobulinaemia with systemic manifestations and liver disease stage and outcome in hepatitis C virus (HCV)-positive patients. We analysed the prevalence of cryoglobulinaemia in a cohort of patients with chronic liver disease and compared the systemic manifestations and liver involvement in HCV-positive patients with type II or type III mixed cryoglobulinaemia. The prevalence of serum cryoglobulins was significantly higher in HCV-positive patients than in hepatitis B surface antigen (HBsAg)-positive patients (55.4 vs 20.6%). In HCV-positive patients, stage of liver disease correlated with the prevalence of cryoglobulinaemia. Patients with type II cryoglobulins showed a significantly higher risk of cirrhosis and of extrahepatic manifestations while patients with type III cryoglobulins had a significantly higher prevalence of hepatocellular carcinoma. During follow-up the former had an odds ratio of 11.9 of death from extrahepatic complications while the latter had an odds ratio of 3.4 of dying from hepatic disease. Our study confirms the high frequency of mixed cryoglobulinaemia in patients with chronic hepatitis C virus infection. The presence and type of cryoglobulins seem to be associated with different clinical manifestations and outcome.

Prolonged treatment (2 years) with different doses (3 versus 6 MU) of interferon alpha-2b for chronic hepatitis type C. Results of a multicenter randomized trial.

BACKGROUND/AIMS: To examine the effect of prolonged treatment with different doses of interferon alpha-2b on the relapse rate in patients with chronic hepatitis C. METHODS: One hundred and seventy-one patients with non-cirrhotic chronic hepatitis C were enrolled in an Italian multicenter trial. All patients were treated for 3 months with 3,000,000 Units (3 MU) of interferon alpha-2b given subcutaneously three times a week (t.i.w.). Patients with abnormal alanine aminotransferase (ALT) values were given 6 MU of interferon for an additional 3 months. If ALT remained persistently abnormal, therapy was then suspended. If ALT levels were normal, therapy was continued (6 MU t.i.w.) for an additional 18 months (total=2 years). Patients with normal ALT were randomly assigned to two groups, one receiving 3 MU and the other receiving 6 MU t.i.w. for an additional 21 months (total=2 years). Follow-up continued for 2 years after therapy withdrawal. RESULTS: Seven patients stopped treatment during the first 3 months. Of the remaining 164 patients, 76 (46%) showed abnormal ALT levels after 3 months of therapy: 11 of these (14%) normalized ALT values when given 6 MU and a sustained response was maintained in eight during the follow-up. Overall, 54 and 34 patients were allocated respectively to the groups receiving the 3 MU and 6 MU long-term treatment. At the end of therapy, 35/54 patients of the group 3 MU and 21/34 patients of the group 6 MU showed normal ALT levels (65% vs 62%, p=N.S.). After 2 years of follow-up, 24/35 (69%) patients of the group 3 MU and 16/21 (76%) of the group 6 MU were still in remission (p=N.S.). In an intention-to-treat analysis, 48/171 (28%) patients showed a long-term response (normal ALT values, HCV-RNA negative). About 65% of the sustained responders showed low baseline viremia compared with 33% of non-responders (p=0.005) while genotype 1b was more frequently found among non-responders than in long-term responders (84% vs 25%, p=0.0001). CONCLUSIONS: About 14% of patients who do not respond to a 3-month course of 3 MU of interferon normalize ALT levels when given 6 MU. In prolonged treatment, there is no significant difference between 3 and 6 MU in inducing a sustained response. Patients with low baseline viremia and genotype 2a respond significantly better to prolonged interferon therapy than highly viremic patients with genotype 1b.

Optimizing the time-frame for the definition of bleeding-related death after acute variceal bleeding in cirrhosis.

OBJECTIVE: To identify the best time-frame for defining bleeding-related death after variceal bleeding in patients with cirrhosis. DESIGN: Prospective long-term evaluation of a cohort of 155 patients admitted with variceal bleeding. SETTING: Eight medical departments in seven hospitals in north-eastern Italy. METHODS: Non-linear regression analysis of a hazard curve for death, and Cox's multiple regression analyses using different zero-time points. RESULTS: Cumulative hazard plots gave two slopes, the first corresponding to the risk of death from acute bleeding, the second a baseline risk of death. The first 30 days were outside the confidence limits of the regression curve for the baseline risk of death. Using Cox's regression analysis, the significant predictors of overall mortality risk were balanced between factors related to severity of bleeding and those related to severity of liver disease. If only deaths occurring after 30 days were considered, only predictors related to the severity of liver disease were found to be of importance. CONCLUSION: Thirty days after bleeding is considered to be a reasonable time-frame for the definition of bleeding-related death in patients with cirrhosis and variceal bleeding.

Randomized trial comparing three different regimens of alpha-2a-interferon in chronic hepatitis C. The TriVeneto Viral Hepatitis Group.

Alpha-interferon (IFN-alpha) is an effective treatment for chronic hepatitis C, but only 20% to 30% of patients are apparently cured with the current recommended schedule of 3 MU given three times a week for 6 months. To evaluate the efficacy of more aggressive treatment regimens, we have conducted a randomized trial in 174 patients with chronic hepatitis C using three different schedules: (1) 12-month treatment starting with 6 MU/ three times a week and decreasing the dose on the basis of serum alanine transaminase (ALT) activities (group A: 59 cases); (2) fixed dose of 3 MU three times a week for 12 months (Group B: 61 cases), (3) fixed dose of 6 MU three times of week for 6 months (Group C: 54 cases). Patients were evaluated during therapy for biochemical and virological response and followed for at least 12 months after therapy to assess long-term efficacy and liver histological outcome. The genotype of infecting HCV was also analyzed in all patients, and predictors of response were determined by multivariate analysis. Serum ALT became normal during therapy in 76% of patients (95% confidence interval [CI]: 63 to 86), 65% (CI: 52 to 77), and 74% (CI: 60 to 85) in groups A, B, and C, respectively (P = NS). The corresponding figures for sustained response 12 months after therapy were 49% (CI: 36 to 62), 31% (CI: 20 to 44), and 28% (CI: 16 to 42)(A vs. B, P = .06; A vs. C, P = 0.03). Eighty-six percent of patients with sustained response cleared HCV-RNA from serum, and 72% improved histologically.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence of higher insulin resistance in NIDDM patients with ischaemic heart disease.

Prospective studies have shown a relationship between hyperinsulinaemia, an indirect index of insulin resistance, and IHD in men with normal glucose tolerance. In NIDDM this association is less clear possibly due to the poor significance of insulin and C-peptide concentrations as an index of insulin resistance. Therefore, only a direct measurement of insulin sensitivity could clarify the possible relationship between insulin resistance and IHD in NIDDM. We have evaluated insulin sensitivity, by means of an ITT, and some risk factors for IHD in 72 men with NIDDM, 36 with and 36 without IHD, attending our out-patient Diabetic Clinic. The two groups were of similar age, duration of diabetes, glycaemic control and body composition. Subjects with IHD were more insulin resistant (K(ITT) index 2.45 +/- 0.18 vs 3.12 +/- 0.13% per min, in patients with and without IHD, respectively, p < 0.004), had higher total (p = 0.011) and LDL serum cholesterol levels (p = 0.010) and greater prevalence of hypertension (p = 0.001) compared to subjects without IHD. Using step-wise logistic regression analysis, insulin resistance (odds ratio 2.57, 95% CI 1.87-3.28, p = 0.008), hypertension (odds ratio 8.17, 95% CI 6.86-9.48, p = 0.002), total serum cholesterol levels (odds ratio 1.02, 95% CI 1.005-1.035, p = 0.015) and BMI (0.79, 95% CI 0.67-0.97, p = 0.049) were independently associated with IHD. After adjustment for age and duration of diabetes, only insulin sensitivity was directly related to the age of onset of IHD, independently from other clinical and metabolic parameters (p < 0.015).(ABSTRACT TRUNCATED AT 250 WORDS)

Patterns of antibodies to hepatitis C virus in patients with chronic non-A, non-B hepatitis and their relationship to viral replication and liver disease.

Patients with hepatitis C virus infection may have circulating antibodies to various structural and nonstructural antigens of the virus. To assess whether the antibody profile is related to epidemiological or clinical features of chronic infection or to viral replication, sera from 172 consecutive patients with biopsy-proven chronic non-A, non-B hepatitis were studied for antibodies to nonstructural and structural hepatitis C virus antigens and for serum hepatitis C virus RNA with the polymerase chain reaction using primers derived from the 5' noncoding region. Three subgroups could be identified on the basis of their seroreactivity to hepatitis C virus: 133 cases (77.3% [group A]) were positive on first- and second-generation assays and had antibodies to C100-3 and to C22, C33c or both identified on recombinant immunoblot assay; 23 cases (13.4% [group B]) were positive only on second-generation assay and reacted with C22, C33c or both but not with C100-3; and 26 cases (9.3% [group C]) were negative for all hepatitis C virus antibodies. Mean age and sex distributions were similar among the three groups; a history of transfusion was more frequent among cases in group B (p = 0.06). These patients also had the highest serum aminotransferase values (p = 0.001). Liver histological studies showed active necroinflammatory changes in 69.2% of patients in group A and 52.2% of those in group B but only in 25% of cases in group C. Serum hepatitis C virus RNA was frequently detected in patients of groups A and B, independent of their recombinant immunoblot assay profiles.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pordenone study: HDL-cholesterol and obesity indexes in the young]. / Studio di Pordenone: HDL-colesterolo e indici di obesità nei giovani.

BACKGROUND: In 1987, ten years after the first observation, we performed the follow-up of the subjects included in the "Pordenone Study on the precursors of atherosclerosis in childhood". METHODS: The anthropometric, biologic and anamnestic indicators of coronary risk were evaluated. The W.H.O. protocol was always used. 439 (90%) subjects underwent reexamination, (234 males and 205 females between 18 and 26 years). HDL cholesterol, tricipital and subscapular skinfold thickness, weight and height were evaluated. The aim of our study was to find possible correlations between obesity indexes and HDL cholesterol values. RESULTS: We found that HDL cholesterol levels are lower in males compared to females and that differences exist below and over the 80 degrees percentile of BMI. Obese subjects have lower HDL cholesterol levels in both sexes. Females with android obesity (subjects with subscapular skinfold thickness values over 80 degrees percentile) had low HDL cholesterol values. CONCLUSIONS: Because of this inverse correlation between HDL cholesterol and coronary risk, and because young obese generally have low HDL cholesterol levels, we believe that the study of coronary risk factors is also useful starting from this age in overweight subjects. This will be useful for preventive purposes. Particular attention must be given to young girls with android obesity.

Clustering of risk factors in hypertensive insulin-dependent diabetics with high sodium-lithium countertransport.

Diabetic nephropathy is more common in patients with a positive family history of hypertension and with elevated red blood cell sodium-lithium countertransport, a marker of risk for essential hypertension. To evaluate whether there is a relationship between this cation transport system and indicators of risk of renal and cardiovascular complications in diabetic patients before the development of clinical proteinuria, we studied 31 type 1 (insulin-dependent) diabetic patients with arterial hypertension, without clinical proteinuria and 12 normotensive normoalbuminuric diabetic patients. Sodium-lithium countertransport activity was significantly higher in hypertensive patients (0.43 +/- 0.03 mmol/l RBC x hr) than in normotensive patients (0.23 +/- 0.03; P less than 0.001). To better explore the nature of the association between this transport system and arterial hypertension, hypertensive patients were divided in two groups, with high (greater than 0.41 mmol/l RBC x hr) or normal (less than 0.41) sodium-lithium countertransport activity. The two groups of hypertensive diabetics were similar in age, sex, body mass index and blood pressure levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Erythrocyte Li+/Na+ and Na+/H+ exchange, cardiac anatomy and function in insulin-dependent diabetics.

It has been proposed that an increased activity of cell membrane Na+/H+ exchange, mirrored by increased erythrocyte Li+/Na+ exchange, may facilitate cell hypertrophy and hyperplasia. Patients with insulin-dependent diabetes mellitus may develop a specific cardiomyopathy with systolic and diastolic abnormalities and increased thickness of the left ventricle. Therefore, we have investigated the relationships between erythrocyte Li+/Na+ and Na+/H+ exchange and echocardiographic parameters in 31 male insulin-dependent diabetics (aged 17-68), in good metabolic control. Three had untreated mild hypertension. In all patients the urinary albumin excretion rate was less than 200 micrograms min-1. Ten patients had a Li+/Na+ countertransport higher than 0.37 mmol l-1 cell h-1, the upper normal limit for our laboratory (0.49 +/- 0.10, mean +/- SD). In comparison with the patients with normal countertransport, they had increased interventricular septum thickness and relative wall thickness (h/r). End diastolic volume and cardiac index were reduced while blood pressure and urinary albumin excretion rate were similar. In the whole study group, interventricular septum thickness was significantly correlated to Li+/Na+ exchange (r = 0.61, P less than 0.001) and Na+/H+ exchange (r = 0.35, P less than 0.05), independently of the effect of age and blood pressure. Posterior wall thickness was correlated to Li+/Na+ exchange (r = 0.38, P less than 0.05) and h/r to Li+/Na+ exchange (r = 0.41, P less than 0.05) and to Na+/H+ exchange (r = 0.44, P less than 0.05). Li+/Na+ exchange was negatively correlated to cardiac index (r = -0.37, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Sodium-lithium countertransport and cardiorenal abnormalities in essential hypertension.

The rate of red blood cell sodium-lithium countertransport is elevated only in a subgroup of patients with essential hypertension. We have therefore compared renal and cardiac function and morphology in two groups of hypertensive patients with high (n = 23) or normal (n = 22) sodium-lithium countertransport (mean +/- SEM: 0.61 +/- 0.10 versus 0.29 +/- 0.07 mmol/l red blood cells.hr). The two groups were similar in age, sex distribution, body mass index, smoking habit, duration of hypertension, and actual levels of untreated blood pressure. Hypertensive patients with elevated sodium-lithium countertransport activity showed elevated glomerular filtration rate (118 +/- 2 versus 109 +/- 2 ml/min.1.73 m2; p less than 0.001), albumin excretion rate (23 +/- 3 versus 14 +/- 2 micrograms/min; p less than 0.001), larger kidney volume (250 +/- 15 versus 203 +/- 13 ml.1.73 m2; p less than 0.01), lower lithium clearance rate (26.7 +/- 0.3 versus 28.9 +/- 0.3 ml/min.1.73 m2; p less than 0.01), and higher total body exchangeable sodium (2,716 +/- 33 versus 2,485 +/- 41 mmol.1.73 m2; p less than 0.01). Left ventricular mass index (139 +/- 6 versus 119 +/- 6 g/m2; p less than 0.05), relative wall thickness (0.39 +/- 0.05 versus 0.29 +/- 0.04 cm; p less than 0.001), and left posterior wall plus intraventricular septum thickness (2.02 +/- 0.04 versus 1.76 +/- 0.03 cm; p less than 0.05) were also higher in patients with high sodium-lithium countertransport. Hypertensive patients with normal sodium-lithium countertransport had renal and cardiac parameters similar to those of a normotensive control group (n = 21) except for a higher glomerular filtration rate and left ventricular mass index.(ABSTRACT TRUNCATED AT 250 WORDS)

[The Pordenone study on the precursors of atherosclosis in childhood. A 10-year follow-up. Cigarette smoking]. / Studio di Pordenone sui precursori dell'aterosclerosi nell'infanzia. Follow-up dopo dieci anni. Il fumo di sigaretta.

We have studied smoking habit in the sample enrolled in the ten year follow-up of the "Pordenone Study on the Precursors of Atherosclerosis in Childhood". The response rate at ten year follow-up was very high (about 90%). Prevalence of smoking is 45.1% among males and 25.6% among females. Males and females aged 23 present a prevalence of smokers higher than the other groups while the group aged 26 smoke less. Males began to smoke at 16.4 years, females at 16.7. Mean daily consumption is 12.6 cigarettes among males, and 5.0 among females. Juvenile experimentation with cigarettes and juvenile smoking habit are strong predictors to smoke ten years later; while parental smoking behaviour is not so influential. Therefore we conclude that smoking habit acquired in youngs has a high probability to be maintained in adults, remarking the importance of planning a preventive intervention as early as possible.

Role of insulin and atrial natriuretic peptide in sodium retention in insulin-treated IDDM patients during isotonic volume expansion.

Because insulin shows an antinatriuretic effect in healthy humans, insulin therapy resulting in circulating hyperinsulinemia may lead to sodium retention and in turn to hypertension in individuals with insulin-dependent diabetes mellitus (IDDM). Moreover, it has been proved that atrial natriuretic peptide (ANP) plays a major role in modulating natriuresis in humans. This study investigated the relationship between insulin and ANP in modulating sodium metabolism in normotensive and hypertensive IDDM subjects compared with control groups of normotensive and hypertensive nondiabetic subjects. IDDM normotensive and hypertensive subjects had mean +/- SE duration of IDDM of 7 +/- 2 and 8 +/- 2 yr, respectively, and had no clinical features of diabetic nephropathy. All subjects received a saline infusion (2 mmol.kg-1.90 min-1) during euglycemia. IDDM normotensive and hypertensive subjects received a subcutaneous insulin infusion (15 mU.kg-1.h-1), resulting in twofold higher plasma free-insulin levels (16 +/- 2 and 19 +/- 3 microU/ml, respectively) than in nondiabetic normotensive and hypertensive subjects (7 +/- 2 and 8 +/- 2 microU/ml, respectively). During saline challenge, sodium excretion increased by 22 +/- 4% in normotensive and 49 +/- 9% in hypertensive nondiabetic subjects but by only 11 +/- 0.4% in normotensive (P less than 0.01) and 8 +/- 2% in hypertensive (P less than 0.01) IDDM subjects. The impaired natriuretic response to saline challenge was mainly due to greater rates of sodium reabsorption by kidney proximal tubules in IDDM than nondiabetic subjects. At baseline, plasma ANP concentrations were significantly higher in both IDDM groups than in control groups (normotensive IDDM and control subjects: 38 +/- 4 and 19 +/- 2 pg/ml, respectively, P less than 0.01; hypertensive IDDM and control subjects: 45 +/- 6 and 27 +/- 4 pg/ml, respectively, P less than 0.05). After saline challenge, ANP concentrations rose to 39 +/- 4 pg/ml in normotensive and 49 +/- 5 pg/ml in hypertensive control subjects, whereas no significant change above baseline value was seen in IDDM subjects. Both IDDM groups showed a 10-12% greater exchangeable Na+ pool than control subjects regardless of the presence of hypertension. Subcutaneous insulin infusion, resulting in circulating plasma free-insulin levels in normotensive control subjects comparable to those in IDDM patients, inhibited natriuresis, increased proximal tubule sodium reabsorption at the level of the kidney, and inhibited an adequate ANP stimulation by saline challenge. We conclude that hyperinsulinemia leads to increased proximal tubule sodium reabsorption and impaired ANP response during saline administration. Both mechanisms account for sodium retention in normotensive and hypertensive IDDM patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Atrial natriuretic factor in hypertensive and normotensive insulin-dependent diabetics.

Since insulin increases renal sodium reabsorption, hyperinsulinaemia in insulin-treated insulin-dependent diabetes mellitus might lead to sodium retention and, in turn, increase atrial natriuretic factor (ANF) values. We investigated ANF levels in insulin-dependent diabetes mellitus with and without hypertension. We infused saline (2 mmol/kg per 90 min) in nine normotensive controls, eight normotensive diabetics, seven hypertensive controls and six hypertensive diabetics during the imposition of a euglycaemic glucose clamp with an artificial pancreas. Baseline ANF values were higher in the normotensive and hypertensive diabetics than in the normotensive and hypertensive controls. During a sodium load the sodium excretion rate increased significantly in controls but not in the diabetic groups. The ANF pattern was similar, values being significantly increased in controls and unchanged in diabetic patients. We conclude that euglycaemic, slightly hyperinsulinaemic, insulin-dependent diabetes mellitus patients with and without hypertension are characterized by higher baseline ANF values and an impaired response to an acute saline load as shown by the sodium excretion rate and the plasma ANF concentration.

Sodium metabolism in insulin dependent diabetic patients. Role of insulin and atrial natriuretic peptide.

Acute insulin administration shows an antinatriuretic effect in normal man. Thus it can be postulated that insulin therapy resulting in circulating hyperinsulinemia can lead to sodium retention and in turn to hypertension in insulin dependent diabetes. Moreover it has been proved that atrial natriuretic peptide (ANP) plays a major role in modulating natriuresis in man. The aim of the present study was to investigate the relationship between insulin and ANP in modulating sodium metabolism in seven insulin dependent diabetic patients in comparison with eight normal control subjects at baseline and during a saline infusion (2 mmol/kg/90 min) at euglycemic blood levels. Diabetics received a subcutaneous insulin infusion (0.015 U/kg/hr) resulting in a two fold higher plasma free insulin levels (16 +/- 2 microU/ml) than in control subjects (7 +/- 2 microU/ml). During saline challenge sodium excretion rate increased by 29 +/- 6% in control patients and only by 6 +/- 0.7% in diabetic patients (p less than 0.01). At baseline ANP plasma concentrations were significantly higher in diabetic patients than in control subjects (diabetics = 37 +/- 8 pg/ml and controls = 21 +/- 3 (p less than 0.01). After saline challenge ANP concentration rose to 71 +/- 9 pg/ml in control subjects, whereas no significant change above baseline values was shown by diabetic patients.