Activation of peritoneal macrophages during the evolution of type 1 diabetes (insulitis) in streptozotocin-treated mice.

The effects of lipopolysaccharide (LPS) and desArg9Bradykinin (DBK) on the release of nitric oxide (NO) from macrophages of mice 8, 12 and 18 days after having been treated with low doses of streptozotocin (STZ; 5 × 45 mg/kg) were studied. The results showed that LPS stimulated the release of NO from macrophages of untreated animals by 50% whereas the bradykinin B(1) agonist desArg9Bradykinin (DBK) increased the level of NO by 20%. This increased NO production was totally abolished by incubating the cells with R-954, a selective bradykinin B(1) antagonist. The release of NO from macrophages of STZ-treated mice incubated in the presence of LPS was more marked and reached approximately 220, 300 and 270% respectively from cells collected 8, 12 and 18 days after the STZ treatment. These significant increases were completely blocked by R-954 and were even below control values. Similarly the results showed that DBK stimulated by 50-75% the release of NO from macrophages of STZ-treated mice. The most marked stimulation was noted when the cells were collected 18 days after the treatment of the animals with STZ. Again in this set of experiments the B(1) antagonist completely blocked the release of NO which went even below control values. The results clearly suggest the upregulation of bradykinin B(1) receptors in mouse macrophages in the early phase of STZ-induced diabetes, an event that could even precede the onset of the diabetic hyperglycemia.

The diabetic nephropathy and the development of hypertension in rats.

The present study was designed to examine the development of hypertension in diabetic rats treated with streptozotocin (STZ, 1 mg/g bw). The rats were studied at 3, 6, 9, 12 and 15 weeks. From the third week the rats were divided in diabetic rats according their glycemias and controls, along 15 weeks. After the third week a group of rats showed increased urinary protein excretion (93, 134, 155 and 191%) compared to controls. In this group of rats the urinary kallikrein excretion was lower than control and the systolic blood pressure became significantly elevated between 3 and 6 weeks and persisted up to 15 weeks. On the other hand a group of diabetic rats were normotensive with urinary protein excretion similar to controls and urinary kallikrein lower compared to control but significantly higher compared diabetic hypertensive rats. These data suggest that the association of progressive diabetic nephropathy with abnormal endothelium-dependent vasodilation may produce a high prevalence of hypertensive diabetes.

Renal ischemia-induced increase in vascular permeability is limited by hypothermia.

The purpose of the present work was to evaluate the kallikrein-kinin system and effects of hypothermia during renal ischemia and reperfusion. Male C57BL/KSJmdb mice were subjected to 20 or 60 min ischemia for different periods of reperfusion. Our results demonstrate that short periods of ischemia followed by reperfusion did not cause significant alterations in kallikrein activity, Evans Blue (EB) extravasation, prokallikreins, myeloperoxidase activity or plasma creatinine concentration. Edema was evident at 1 h reperfusion in the treated mice, but returned to basal values after 24 h reperfusion. Kallikrein activities and EB extravasation showed a significant increase in 60 min ischemic mice. Myeloperoxidase activity in the kidney of the mice confirmed net infiltration in the group with 60 min ischemia and 24 h reperfusion. The generation of kinins and activation of matrix degrading enzymes by tissue kallikrein, liberated from both renal and infiltrated leukocytes, could be responsible at least in part for the damage observed in the kidney of mice subject to 60 min ischemia and reperfusion. The hypothermia significantly reduced the inflammatory process in the 60 min ischemic mice, and did prevent an increase in vascular permeability. Nevertheless, the tissue edema was not shown to change between normothermic and hypothermic ischemic mice.

The involvement of kallikrein-kinin system in diabetes type I (insulitis).

Islet inflammation or insulitis is followed by selective destruction of the insulin secreting B-cell. Animal models of insulin-dependent diabetes mellitus (IDDM) have been used to characterize more fully insulitis, and our results with C57/BL/Ks mdb with low doses of streptozotocin (STZ) confirmed the disease. B1 receptor antagonist [Leu8]des-Arg9-BK has shown a significant effect on diabetic glycemia and renal control parameters. Compared to insulin, the drug was effective to prevent the insulitis and the renal damage. On the other hand, B2 receptor antagonist (HOE 140) and ACE-I (captopril) were only able to control the urinary diabetic proteinuria.

Renal function in the diabetic pregnant rats.

Diabetic nephropathy is associated with increased urinary albumin and reduce kallikrein excretion. Increased activity of the renal kallikrein-kinin system has been suggested as one of the possible mechanisms underlying diabetic hyperfiltration. The present study shown that the Kallikrein-kinin system is progressively increased in the diabetic-pregnant rats at 7, 14, 21 days; 48 and 7 days after pregnancy (P < 0.05 vs Control). However, this increase during diabetic pregnancy did not reached the levels of control pregnancy. On the other hand albumin excretion shown a significant and progressive renal damage in the diabetic state. These findings suggest that the diabetic pregnancy could impair the renal hemodynamic, but, on the other side could modulate the vasodilator system at pregnancy in the attempt to protect the fetus.

Renal function in the diabetic pregnant rats.

Diabetic nephropathy is associated with increased urinary albumin and reduce kallikrein excretion. Increased activity of the renal kallikrein-kinin system has been suggested as one of the possible mechanisms underlying diabetic hyperfiltration. The present study shown that the Kallikrein-kinin system is progressively increased in the diabetic-pregnant rats at 7, 14, 21 days; 48 and 7 days after pregnancy (P < 0.05 vs Control). However, this increase during diabetic pregnancy did not reached the levels of control pregnancy. On the other hand albumin excretion shown a significant and progressive renal damage in the diabetic state. These findings suggest that the diabetic pregnancy could impair the renal hemodynamic, but, on the other side could modulate the vasodilator system at pregnancy in the attempt to protect the fetus.

Constitutive nitric oxide synthase (cNOS) activity in Langerhans islets from streptozotocin diabetic rats.

Nitric oxide synthase activity was measured in Langerhans islets isolated from control and streptozotocin diabetic rats. The activity of the enzyme was linear up to 150 micrograms of protein from control rats and was optimal at 0.1 microM calcium, when it was measured after 45 min of incubation at 37 degrees C in the presence of 200 microM arginine. Specific activity of the enzyme was 25 x 10(-4) nmol [3H]citrulline 45 min-1 mg protein-1. Streptozotocin diabetic rats exhibited less enzyme activity both in total pancreas homogenate and in isolated Langerhans islets when compared to control animals. Nitric oxide synthase activity measured in control and diabetic rats 15 days after the last streptozotocin injection in the second group of animals corresponded only to a constitutive enzyme since it was not inhibited by aminoguanidine in any of the mentioned groups. Hyperglycemia in diabetic rats may be the consequence of impaired insulin release caused at least in part by reduced positive modulation mediated by constitutive nitric oxide synthase activity, which was dramatically reduced in islets severely damaged after streptozotocin treatment.

Effects of L-NAME and L-Arg on arterial blood pressure in normotensive and hypertensive streptozotocin diabetic rats.

The present study was designed to examine blood pressure response to nitric oxide synthase-pathway inhibition and stimulation in normotensive and hypertensive diabetic rats. Rats treated with streptozotocin (60 mg/Kg i.p.) developed high blood glucose, polyuria and slow weight gain compared with control. One group of diabetic rats developed hypertension, consequently we studied three experimental groups: control rats (C), normotensive diabetic rats (ND) and hypertensive diabetic rats (HD). Mean arterial pressure (MAP), systolic blood pressure, diastolic blood pressure and heart rate were recorded: baseline time, 30 after L-nitro arginine methyl ester (L-NAME: 1 mg/Kg i.v.) and post L-arginine (L-arg: 250 mg/Kg i.v.) injection. L-NAME induced a significantly increase in MAP in all groups. This enhancement was smaller in diabetic than in control rats. The increase in MAP in HD was significantly lower than that in ND L-arg induced a significantly decrease in MAP in all groups. This decrease was significantly attenuated in diabetic compared with control rats. The degree of hypotension in response to L-arg in diabetic groups was lower in hypertensive than that in normotensive diabetic rats. These data suggest that an impairment of nitric oxide formation could be involved in the development of hypertension in this model.

Constitutive nitric oxide synthase (cNOS) activity in Langerhans islets from streptozotocin diabetic rats

Nitric oxide synthase activity was measured in Langerhans islets isolated from control and streptozotocin diabetic rats. The activity of the enzyme was linear up to 150 mug of protein from control rats and was optimal at 0.1 muM calcium, when it was measured after 45 min of incubation at 37ºC in the presence of 200 muM arginine. Specific activity of the enzyme was 25 x 10(-4) nmol [3H] citrulline 45 min(-1) mg protein(-1). Streptozotocin diabetic rats exhibited less enzyme activity both in total pancreas homogenate and in isolated Langerhans islets when compared to control animals. Nitric oxide synthase activity measured in control and diabetic rats 15 days after the last streptozotocin injection in the second group of animals corresponded only to a constitutive enzyme since it was not inhibited by aminoguanidine in any of the mentioned groups. Hyperglycemia in diabetic rats may be the consequence of impaired insulin release caused at least in part by reduced positive modulation mediated by constitutive nitric oxide synthase activity, which was dramatically reduced in islets severely damaged after streptozotocin treatment.

Effects of aprotinin on the kallikrein-kinin system in type I diabetes (insulitis).

Sub-diabetogenic doses of streptozotocin (STZ) produce insulitis, beta cell destruction and diabetes in mice. Since kinin have been proposed as an inflammatory mediator in several diseases, we decided to evaluate the role of the kallikrein-kinin system in the evolution of insulitis. Male C 57 BL/KsJ mdb mice were injected with STZ (40 mg/kg) for 5 consecutive d. Aprotinin (4000 KIU/d) was injected simultaneously with STZ during 10 d. Plasma and urine samples collected on day 15 were assayed for glucose concentration and proteins, nitrites and kallikrein. Diabetic mice showed hyperglycemia and increased diuresis, marked proteinuria, nitrites and kallikrein. Administration of aprotinin, a potent tissue kallikrein inhibitor, to STZ mice, reduced the hyperglycemia and the altered renal function of the diabetic mice to level no different from normal mice. The present studies are consistent with the hypothesis that the over-production of tissue kallikrein in insulitis could be controlled by the effect of aprotinin.

Effects of B1 and B2 kinin receptor antagonists in diabetic mice.

Streptozotocin (STZ) has been extensively used to produce type I diabetes in animals. This experimental disease is characterized by a mild inflammatory reaction in the Langerhans islets. Because kinins have been proposed as prominent inflammatory mediators in the pathogenesis of several diseases, we decided to evaluate the role of kinins and their receptors in the evolution of insulitis. Male C57BL/Ks mdb mice were injected with STZ (40 mg/kg) for 5 consecutive days. The kinin B1 receptor antagonist [Leu8]des-Arg9-bradykinin or the B2 antagonist d-Arg[Hyp3,Thi5,D-Tic7, Oic8]bradykinin (HOE-140) was injected subcutaneously into STZ mice at 300 micrograms/kg body weight twice a day and 500 micrograms/kg per day, respectively. Treatment with antagonists was started 3 days after STZ and lasted for 10 days. Plasma glucose was determined by the glucose oxidase method, and urine samples collected on day 13 were assayed for proteins, nitrites, and kallikreins. Diabetic mice showed hyperglycemia and increased diuresis, marked proteinuria, and increased excretion of nitrites and kallikreins. The treatment with the B2 receptor antagonist did not show any effect on glycemia, but it significantly reduced water and protein excretion, compared with the STZ group. STZ mice treated with the B1 receptor antagonist showed normal glycemia and complete normalization of diuresis and protein, nitrite, and kallikrein excretion. The results obtained in the present investigation support the assumption that the kallikrein-kinin system intervenes in the maintenance of diabetic lesions, and they also indicate that B1 kinin receptors play a significant role in this experimental disease.

Effects of HOE 140 on some renal functions in type I diabetic mice.

To investigate in mice the mechanisms underlying renal functions in a type I diabetes model, we have suppressed B2 kinin receptors local activities by their specific antagonist D-Arg [Hyp3-Thi5-D-Tic7-Oic8]BK (HOE 140). Mice made diabetic with low consecutive doses of streptozotocin (STZ) (45 mg/k BW during 5 days) were injected with HOE 140 (15 micrograms/twice a day) for 15 days. This drug did not modify glycemia of STZ treated animals but a significantly reduction of urinary proteins, nitrites and kallikrein was observed. These results indicate that kinin B2-receptors activation is implicated in the alterations of renal function in this model of type I diabetes in mice.

Streptozotocin-induced hyperglycemia is decreased by nitric oxide inhibition.

1. Diabetes mellitus type I was induced in 3-month old male C57 BL/KS-mdb mice (N = 24) by ip injection of streptozotocin (STZ, 45 mg/kg body weight) for 5 days. 2. To determine the possible protective effects of nitric oxide inhibition against hyperglycemia, the STZ-diabetic rats received two doses of NG-nitro-L-arginine- methyl ester (L-NAME) (10 mg/kg body weight and 10 mg/mouse) dissolved in PBS for 45 consecutive days. Another group of STZ-treated rats was similarly treated with L-arginine (5 mg/mouse). 3. Blood glucose levels were 118 +/- 37 mg/dl after 8 days of L-NAME administration (10 mg/kg body weight, N = 12) and 186 +/- 22 mg/dl (N = 12) after 5 days of L-NAME administration at the 5 mg/mouse dose. Treatment with L-arginine (5 mg/mouse, N = 12) caused a significant increase in blood glucose level to 151 +/- 17.5 mg/dl, showing the relevance of nitric oxide formation in this type of diabetes. 4. In STZ-diabetic mice treated with L-NAME (N = 12), diuresis was reduced by approximately 58% compared to STZ animals, whereas in L-arginine-treated animals (N = 12) diuresis returned to STZ levels. Urinary protein excretion, which was significantly affected by STZ (123% compared to control) was significantly reduced by 66% after treatment with L-NAME for 45 days, whereas treatment with L-arginine caused a return to STZ values. 5. Urinary kallikrein excretion, which was reduced by 80% in STZ mice compared to control, returned to control levels after L-NAME treatment. 6. The present results suggest a relationship between nitric oxide levels and the reduction of diabetic state and improved renal function by L-NAME.

Streptozotocin induced hyperglycemia is decreased by nitric oxide inhibition

1. Diabetes mellitus type 1 was induced in 3-month old maleC57 BL/KS-mdb mice (N = 24)) by ip injection of streptozotocin (STZ, 45 mg/Kg body weight) for 5 days. 2. To determine the possible protective effects of nitric oxide inhibition against hyperglycemia, the STZ-diabetic rats received two doses of Ng-nitro-l-arginine-methyl ester (L-NAME) (10 mg/Kg body weight and 10 mg/mouse) dissolved in PBS for 45 consecutive days. Another group of STZ-treated rats was similarly treated with L-arginine (5 mg/mouse). 3. Blood glucose levels were 118 ñ 37 mg/dl after 8 days of L-NAME administration (10 mg/Kg body weight, N = 12) and 186 ñ 22 mg/dl (N = 12) after 5 days of L-NAME administration at the 5 mg/mouse dose. Treatment with L-arginine (5-mg/mouse, N = 12) caused a significant increase in blood glucose level to 151 ñ 17,5 mg/dl, showing the relevance of nitric oxide formation in this type of diabetes. 4. In STZ-diabetic mice treated with L-NAME (N = 12), diuresis was reduced by approximately 58 per cents compared to STZ animals, whereas in L-arginine-treated animals (N = 12) diuresis returned to STZ levels. Urinary protein excretion, which, was significantly affected by STZ (123 per cents compared to control) was significanty reduced by 66 per cents after treatment with L-NAME for 45 days, whereas treatment with-L-arginine caused a return to STZ values. 5. Urinary kallikrein excretion, which was reduced by 80 per cents in STZ mice compared to control, returned to control levels after L-NAME treatment. 6. The present results suggest a relationship between nitric oxide levels and the reduction of diabetic state improved renal function by L-name

Renal alteration and development of hypertension in diabetic rats.

UNLABELLED: There is a close association between diabetes and hypertension. Many studies have demonstrated an increased incidence of hypertension in the presence of diabetic nephropathy. The aim of the present work was to study the kallikrein-kinin system during the diabetic states with hypertension. In this study neonatal rats were injected with streptozotocin at two days of age. Plasma glucose, proteinuria, urinary kallikrein, blood pressure, creatinine clearance, diuresis and body weight were measured. RESULTS: control rats vs diabetic rats. Plasma glucose (mg/dl): 0 minutes 80.2 +/- 2.5 vs 105.5 +/- 4.5; 60 minutes 120.4 +/- 2.3 vs 220.0 +/- 4.6; 120 minutes 105.0 +/- 1.5 vs 140.0 +/- 3.6; p < 0.05. Proteinuria at 8 months of age (mg/24 hs): 12.5 +/- 1.6 vs 20.6 +/- 2.4; p < 0.05. Urinary kallikrein at 8 months of age (umol/min/24 hs)/(ml/min) x 10(3): 46.9 +/- 3.0 vs 28.5 +/- 2.5; p 0.005. Blood pressure at 8 months of age (mm Hg): 110.0 +/- 2.0 vs 132.0 +/- 4.0; p < 0.001. Creatinine clearance at 10 months of age (ml/min): 0.46 +/- 0.03 vs 0.70 +/- 0.14; p < 0.05. Diuresis at 8 months of age (ml/24 hs): 1.55 +/- 0.65 vs 10.30 +/- 1.44, p < 0.001. The early modifications of kallikrein-kinin system in the diabetes states may contribute to development hypertension with modifications in the hemodynamics renal function.

The kallikrein-kinin system in early state of diabetes.

The kallikrein-kinin system was studied in 9 normals, healthy subjects (6 men, 3 women, age range 1 to 14 years) and 15 diabetic patients (9 men, 6 women age range 2 to 14 years) with an evolution of the disease between 1 to 14 years. Diabetic patients with low microalbuminuria (6.62 +/- 0.97 mg/24 h) show increased total and pre-kallikrein respect to control (3 and 2 fold respectively). On the other hand patients with high microalbuminuria (44.7 +/- 13.2 mg/24 h) show a total and pre-kallikrein of more than 4 and 8 fold increased respectively, compare with the control. According with these results we can concluded: 1) The total kallikrein and pre-kallikrein is increased in the diabetic state. 2) When microalbuminuria is high, the total and pre-kallikrein correlates with those increasing. 3) These changes could modified the renal hemodynamic in diabetes.

The kallikrein-kinin system of sweat in normal and cystic fibrosis subjects.

The mechanisms of kallikrein secretion was studied in 25 normal subjects (11 male, 14 female) and 5 subjects with cystic fibrosis (identified by the usual criteria). The results obtained show a decreasing of prekallikrein and total kallikrein in cystic fibrosis stimulated by IPR or pilocarpine compare to controls. On the other hand sweat from males shows more prekallikrein and total kallikrein than females. According with this results we can concluded that the basic defect in sweat cystic fibrosis gland could be the possible involvement of the kallikrein-kinin system on the high osmolality of the sweat secretion.

The kallikrein-kinin system in the colon and lung fluid from a cribriform degeneration (cri) mutant mouse.

The cribriform degeneration (cri) mutant mouse was widely studied in regard to the electrolyte and kallikrein metabolism because of its potentiality as a cystic fibrosis (CF) genetic animal model. In this paper the activity of the kallikrein-kinin system, and the kininase activity and glycoproteins concentration in colon and pulmonary lavage fluid (PLF) in homozygous mutant (cri/cri) and control sibling mice are described. The mutant mice showed a diminished kininogenase and kininase activity and glycoproteins concentrations in both studied organs. It is concluded that a kallikrein-kinin system alteration could be responsible of the cri/cri electrolyte defect.