Inhibition of primary and secondary nucleation alongwith disruption of amyloid fibrils and alleviation of associated cytotoxicity: A biophysical insight of a novel property of Chlorpropamide (an anti-diabetic drug).

Aggregation of physiologically synthesized soluble proteins to insoluble, cytotoxic fibrils is a pre-requisite for pathogenesis of amyloid associated disorders including Alzheimer's disease, non-systemic amyloidosis, Parkinson's disease, etc. Considerable advancement has been made to understand the mechanism behind aggregation process but till date we have no efficient cure and preventive therapy for associated diseases. Strategies to prevent protein aggregation are nevertheless many which have been proved promisingly successful in vitro. One of those is repurposing already approved drugs that saves time and money too and has been employed in this study. Here, for the first time we are reporting the effectiveness of an anti-diabetic drug chlorpropamide (CHL) under dosage conditions, a novel property to inhibit aggregation in human lysozyme (HL) in vitro. Spectroscopic (Turbidity, RLS, ThT, DLS, ANS) and microscopic (CLSM) results demonstrates that CHL has the potency to suppress aggregation in HL up to 70 %. CHL is shown to affect the elongation of fibrils with IC50 value of 88.5 µM as clear from the kinetics results, may be by interacting near/with aggregation prone regions of HL. Hemolytic assay also revealed the reduced cytotoxicity in the presence of CHL. Disruption of amyloid fibrils and inhibition of secondary nucleation in the presence of CHL was also evidenced by ThT, CD and CLSM results with reduced cytotoxicity as confirmed by hemolytic assay. We also performed preliminary studies on α-synuclein fibrillation inhibition and surprisingly found that CHL is not just inhibiting the fibrillation but also stabilizing the protein in its native state. These findings insinuate that CHL (anti-diabetic) possess multiple roles and can be a promising drug for developing therapeutic against non-systemic amyloidosis, Parkinson's disease and other amyloid associated disorders.

Antidiabetic properties of ethanolic extract of Cnidoscolus aconitifolius on alloxan induced diabetes mellitus in rats.

This research was designed to investigate the antidiabetic properties of ethanolic extract of Cnidoscolus aconitifolius in alloxan-induced diabetes mellitus in Wistar male albino rats. Thirty male albino rats were used. Diabetes mellitus was induced in five of the six groups (B-F) by a single intra-peritoneal injection at the dose of 100mg/kg after normal fasting blood glucose had been determined. Group A served as the positive control while groups C-E received 100mg/kg, 500mg/kg and 1000mg/kg of Cnidoscolus aconitifolius extract respectively. Group B did not received any treatment while group F received chlorpropamide, a standard drug used in the treatment of diabetes mellitus. Blood glucose and body weights were monitored weekly for four weeks. Plasma lipids and electrolytes such as Total cholesterol, Triglyceride, Low Density Lipoproteins (LDL), High Density Lipoproteins (HDL), Creatinine and Blood Urea Nitrogen (BUN) were determined after four weeks of treatment with Cnidoscolus aconitifolius extract. The results show significant reduction (P<0.001) in the blood glucose in group C (100mg/kg of Cnidoscolus aconitifolius) when compared with diabetic control (Alloxan only) and other treatment groups. There was gradual increase in weight of all treatment groups compared with the diabetic control, which had progressive weight loss. Plasma cholesterol levels also significantly reduced (P<0.001) in rats treated with 1,000mg/kg Cnidoscolus aconitifolius extract. From this study, Cnidoscolus aconitifolius extract was found to considerably reduce blood glucose and plasma cholesterol levels and progressively increase weight gain in diabetic treated rats confirming its traditional use for the treatment of diabetes.

Effect of Nigerian meals on the pharmacokinetics of chlorpropamide in type II diabetic patients.

Food-drug interactions are best evaluated on an individual drug basis, in a group of subjects in a population at risk. This is due to their complex nature, which is a function of type and size of meal, the physical and chemical form of the drug and the time lapse between food intake and drug administration. This work was aimed at investigating the effect of three different Nigerian meals, which are regularly consumed by the three major tribes in Nigeria, on the pharmacokinetics of chlorpropamide, a drug commonly used to treat Type II diabetes in this country. Meal A (maize flour meal) was composed of 81% carbohydrate, 3% protein and 11% fat; meal B (cassava flour meal) was composed of 76% carbohydrate, 3% protein and 15% fat; while meal C (browned yam flour meal) was composed of 85% carbohydrate, 2% protein and 8% fat. The effects of the three meals were investigated by administering each of the meals alone, without the medicinal drug (Treatment I); in Treatment II each meal was administered 30 min following the administration of 250 mg chlorpropamide; in Treatment III the drug was administered together with each of the standard meals. Analysis of the plasma levels of chlorpropamide was performed by high performance liquid chromatography (HPLC). Ingestion of the meal alone (Treatment I) resulted in a significant difference in postprandial plasma glucose levels. The time to maximum plasma chlorpropamide concentration was significantly increased in Treatment III (P < 0.05), while all pharmacokinetic parameters and plasma glucose levels were not significantly altered in Treatment II. Analysis of the results demonstrated a better glycaemic response with meals A and C compared with meal B.

"Essential" hypernatremia due to ineffective osmotic and intact volume regulation of vasopressin secretion.

A physiological explanation for sustained hyperosmolality was sought in a patient with histiocytosis. During 23 days of observation with only sodium intake regulated at 100 mEq daily, elevation (mean 310 mOsm/kg of water) and fluctuation (range 298-323) of the fasting plasma osmolality were recorded. The presence of endogenous vasopressin was indicated by the patient's ability to concentrate the urine to as high as 710 mOsm/kg of water with a creatinine clearance of 84 cc/min, and by dilution of the urine in response to alcohol. The failure of increasing fluid intake to as high as 6.2 liters daily to lower the plasma osmolality indicated that deficient fluid intake was not solely responsible for the elevated plasma osmolality. Hypertonic saline infusion during water diuresis resulted in the excretion of an increased volume of dilute urine. The water diuresis continued despite a rise in plasma osmolality from 287 to 339. An isotonic saline infusion initiated during hydropenia resulted in a water diuresis which continued despite a rise in the plasma osmolality from 303 to 320. Stable water diuresis induced during recumbency by either oral ingestion of water or intravenous infusion of normal saline was terminated by orthostasis and resumed with the return to the recumbent position. Antecedent alcohol ingestion blocked the antidiuresis of orthostasis. The data are interpreted as indicating impairment of the osmoreceptor mechanism as the primary cause of the hyperosmolar syndrome. They also indicate that vasopressin secretion was regulated primarily by changes in effective blood volume. Chlorpropamide was found to be an effective treatment for the syndrome.

Peripheral and autonomic nerve function in newly diagnosed diabetes mellitus.

Peripheral and autonomic nerve function was assessed in 10 newly diagnosed male diabetics (six insulin-treated and four sulfonylurea-treated) with repeated observations over the subsequent six months. There was significant impairment of motor-conduction velocity in the common peroneal nerve at diagnosis in both treatment groups, with improvement following treatment in only the insulin-treated patients. In contrast, although the blood glucose level fell in both groups, the mean level was significantly lower in the sulfonylurea-treated patients at two months and at each subsequent visit. In the autonomic function tests significant abnormality was found in the electrocardiographic R-R-interval (beat-to-beat) variation in resting heart rate in two of the insulin-treated patients and all of the sulfonylurea-treated group, with improvement in only one of the latter. One patient in the sulfonylurea-treated group also showed an abnormal response to the Valsalva maneuver (expressed as the Valsalva ratio), and this remained abnormal throughout the period of study. All other patients had normal responses to the Valsalva maneuver and sustained handgrip test. None of the patients had postural hypotension. Abnormalities in autonomic nerve function in diabetics at diagnosis have not been previously reported.

Measurement of antidiabetic sulfonylureas in serum by gas chromatography with electron-capture detection.

A method is described for measurement of chlorpropamide, tolbutamide, and the tolbutamide metabolites hydroxymethyltolbutamide and carbotytolbutamide in blood. It consists of formation of the thermally stable methyl-trifluoroacetyl derivatives of chlorpropamide and tolbutamide, and the methyl-heptafluorobutyryl derivatives of hydroxymethyltolbutamide and carboxytolbutamide, which are then analyzed by electron-capture gas chromatography. Measurements of blood levels of the compounds with this method have been verified by quantitation of the same samples using gas chromatography-mass spectrometry in the mass fragmentography mode. Blood level values and beta-phase half-time disappearance rates of chlorpropamide, tolbutamide, hydroxymethyltolbutamide, and carboxytolbutamide were measured in normal volunteers following an oral dose of chlorpropamide or tolbutamide. Blood levels of the four compounds were also determined in a few diabetics receiving continuous daily treatment.

betacell function during insulin or chlorpropamide treatment of maturity-onset diabetes mellitus.

Maturity-onset diabetic patients usually have raised overnight-fasting plasma glucose levels associated with "normal" basal plasma insulin levels. The basal hyperglycemia is proportional to the degree of insulin deficiency. Basal insulin or C-peptide levels become subnormal if normal fasting plasma glucose levels are attained with insulin. Basal hyperglycemia is probably a compensatory response to maintain near-normal basal insulin levels. A logical therapy of maturity-onset diabetes is to produce basal normoglycemia by means of a constant basal insulin supplement, which can be provided by ultralente insulin. The reduced insulin response of diabetics to intravenous glucose is slightly increased when basal normoglycemia is established, suggesting that the high plasma glucose levels compromise beta cell function. The insulin response to meals in a mild diabetic is not affected by mild hyperglycemia but can be depleted if gross hyperglycemia occurs. Maintenance of normoglycemia then allows beta cell "recovery". In mild diabetics (c. less than 9 mmol per liter basal plasma glucose), chlorpropamide sufficiently stimulates beta cell secretion so that basal normoglycemia can be produced. The C-peptide response to meals is improved, whereas comparable reduction of the plasma glucose with insulin does not alter the meal response. Thus basal normoglycemia can be produced by "resting" beta cells with a basal insulin supplement or by stimulating them with sulfonylurea therapy.

The effect of chronic sulfonylurea therapy on hepatic glucose production in non-insulin-dependent diabetes.

In 20 patients with untreated non-insulin-dependent diabetes mellitus (NIDDM), there was a positive relationship between fasting plasma glucose (FPG) and glucose production rate, calculated by the isotope dilution technique (r = 0.72, P less than 0.001). This suggests that glucose production rate is an important determinant of FPG in untreated NIDDM. Fifteen patients were also studied during therapy with chlorpropamide for 3-6 mo. During therapy, FPG was lower (133 +/- 9 vs. 216 +/- 20 mg/dl, mean +/- SEM; P less than 0.001), glucose production was lower (59.5 +/- 2.0 vs 77.6 +/- 4.9 mg/m2/min; P less than 0.005), and there was a significant correlation between the fall in glucose production and the fall in FPG (r = 0.59, P less than 0.05). Fasting IRI levels increased in some, but not all, patients during chlorpropamide (untreated 18 +/- 2, treated 21 +/- 2 muU/ml; P= NS). However, there was a significant relationship between the percent rise in IRI and the fall in glucose production during treatment (r = 0.75, P less than 0.001). Patients with a rise in fasting insulin during therapy had a greater fall in glucose production than those whose insulin did not rise (25.4 +/- 8.1 vs. 7.8 +/- 2.4 mg/m2/min; P less than 0.005). When a low-dose insulin infusion was given to approximate the increases of portal venous insulin during therapy, similar falls of glucose production occurred. We conclude that inhibition of endogenous glucose production during chronic chlorpropamide therapy is an important mechanism for the lowering of FPG and that enhanced insulin secretion is the reason for the major part of this inhibition. The small fall in glucose production in those patients whose insulin level did not rise during therapy suggests an additional contribution by some other mechanism.

Long-range implications for the mother. The Aberdeen experience.

One hundred twelve women with impaired glucose tolerance (IGT) diagnosed by intravenous glucose tolerance test (IVGTT) after pregnancy were followed up for a period of up to 22 yr (mean 12.9 yr). About one-third have been treated with chlorpropamide and the others by diet only. At the final assessment, approximately 35% had abnormal intravenous glucose tolerance and less than 7% overt diabetes. Chlorpropamide did not prove significantly more effective than diet only. Factors associated with deterioration in glucose tolerance were age at diagnosis and follow-up and the initial fasting plasma glucose (FPG) level (greater than or equal to 5.8 mM), but obesity was less important, although it was associated with an increased rate of vascular complications. Tests for islet cell antibodies (ICA) were weakly positive in 12.5% of 72 subjects and in only 0.5% of an unselected population; they did not correlate with the final state of glucose tolerance. Only three patients developed insulin-dependent diabetes (IDDM) and did so before the ICA study was started. A comparison is made between the results reported by O'Sullivan in patients diagnosed as having gestational diabetes, only 2% of whom still had abnormal oral glucose tolerance postpartum, and the results of our patients, all of whom had IGT after pregnancy. In spite of differences of technique and in the populations studied, the prevalence of IGT and overt diabetes at follow-up was significantly less in the Aberdeen series, who were initially a higher risk group. It seems probable that this is mainly attributable to dietary treatment in the follow-up period as O'Sullivan's cases were treated only during pregnancy.

Potentiation of hypoglycemic effect of chlorpropamide and phenfromin by halofenate.

The potentiation of oral hypoglycemic drugs by the antilipemic agent halofenate is reported. Forty-seven diabetic patients were treated for 48 weeks with halofenate, clofibrate, or placebo. Five patients in the halofenate group were taking phenformin plus either chlorpropamide or tolbutamide. Their average initial fasting plasma glucose was 160 mg./dl. All five patients experienced a slow but but substantial fall in fasting plasma glucose. The mean fasting plasma glucose for the five patients after 80 days of halofenate treatment was 63 mg./dl. As oral treatment for diabetes was reduced, the fasting plasma glucose returned to prehalofenate levels. In this study, we did ont detect an effect of halofenate on the fasting plasma glucose of diabetic patients treated with insulin or on the fasting plasma glucose levels of patients treated with diet alone.

The effects of long-term therapy with oral hypoglycemic agents on the oral glucose tolerance test dynamics in male chemical diabetics.

The effect of fixed doses of oral hypoglycemic agents and placebo (diet alone) on the blood glucose, serum insulin, triglyceride, and cholesterol responses during oral glucose tolerance tests done annually for up to four years' follow-up was studied, in a double-blind manner, in five groups of mild male chemical diabetics. The drugs used were chlorpropamide (100 mg. O.D.), tolbutamide (500 mg. b.i.d.), phenformin (50 mg. O.D.), acetohexamide (250 mg. O.D.), and placebo. Each subject was given an individualized diet aimed at attaining and maintaining ideal weight. Comparison by chi-square analysis between the placebo group and each of the drug groups showed (a) no significant differences with regard to the number of subjects with normal glucose tolerance in each of the tests and (b) no change in the insulin secretion dynamics. Comparison between the initial test and each of the subsequent tests within each group showed (a) a greater number of subjects with normal glucose tolerance in the first follow-up test in the chlorpropamide group only, (b) no change in the insulin secretion dynamics except in the chlorpropamide group, where there was an increased insulin/glucose ratio in the first follow-up test, and (c) no change in the fasting serum triglyceride and cholesterol levels.

Islet changes induced by hyperglycemia in rats. Effect of insulin or chlorpropamide therapy.

To investigate the effect of hyperglycemia on normal islets, rats were made diabetic by a 95% partial pancreatectomy and treated with insulin, saline, or chlorpropamide for 3 mo. Histologic examination and morphometry of the residual pancreas showed islet enlargement and fibrosis that correlated with the mean lasting plasma glucose during the experimental period. Treatment of diabetes with insulin prevented the islet disorganization. The B-cell area per islet remained constant and was not affected by hyperglycemia. Chlorpropamide had little effect on the fasting plasma glucose or islet structure, and no "beta cytotrophic" effect was seen. Chronic hyperglycemia induces islet damage that may affect residual B-cell function in diabetes.

U.K. prospective diabetes study. II. Reduction in HbA1c with basal insulin supplement, sulfonylurea, or biguanide therapy in maturity-onset diabetes. A multicenter study.

Newly presenting maturity-onset diabetic subjects were put on diet and if, after 3-4 mo, their fasting plasma glucose continued greater than 6 mmol/L, they were randomized to three therapies: (1) continuing diet alone, (2) with additional sulfonylurea, or (3) with additional basal insulin supplement provided by ultralente insulin. Obese patients were also randomized to metformin therapy. The aim was to lower the fasting plasma glucose to less than 6 mmol/L and the degree to which this reduced the hemoglobin A1C (HbA1C) concentration was studied in 195 patients over 1 yr. Sulfonylurea and insulin similarly reduced (P less than 0.001) the fasting plasma glucose from 8.3 +/- 1.9 to 6.7 +/- 1.3 mmol/L (mean +/- 1 SD) and 8.6 +/- 2.2 to 6.8 +/- 1.4 mmol/L, respectively. This was accompanied by a significant reduction (P less than 0.001) of the HbA1C to the high normal range, from 9.1 +/- 2.1% to 7.8 +/- 1.2%, and from 9.1 +/- 1.9% to 8.1 +/- 1.3%, respectively, both values at 1 yr being significantly (P less than 0.05) lower than in patients randomized to diet alone. Patients randomized to diet alone had little change in fasting plasma glucose (8.6 +/- 1.8 to 9.3 +/- 2.3 mmol/L) or HbA1C (8.8 +/- 1.7% to 9.1 +/- 1.6%, respectively). Thus, the simple therapeutic aim of trying to reduce the fasting plasma glucose to less than 6 mmol/L is an effective means of reducing the HbA1C to a high-normal level. The HbA1C and fasting plasma glucose concentrations were similarly related for all three therapies (HbA1C [%] = 0.47 X fasting plasma glucose [mmol/L] + 4.7).(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of chronic oral antidiabetic therapy on insulin and glucagon responses to a meal.

Nineteen maturity-onset diabetic patients receiving oral hypoglycemic therapy in a university diabetes clinic completed a study to assess the efficacy of the oral agents and to determine their effects on pancreatic islet hormone secretion. All patients were receiving sulfonylureas, and seven were also receiving phenformin. The subjects were studied as outpatients in the clinic setting on four different occasions with collections of a baseline blood sample before a standard breakfast and a second sampling two hours postprandially, twice while on their prescribed medication and twice after having been withdrawn from the medication. The values obtained during the two studies on the two studies off medications were reproducible for each subject. Analysis of the results by paired differences revealed that mean 24-hour urine glucose values deteriorated significantly (p less than 0.005) after oral antidiabetic therapy was withdrawn; similarly, mean plasma glucose values, both at baseline and two hours postprandially, rose significantly (p less than 0.001) when subjects were off medication. Baseline serum insulin values were not changed, but postprandial levels were significantly higher on oral agents (p less than 0.005). Plasma immunoreactive glucagon was significantly lower both at baseline (p less than 0.02) and postprandially (p less than 0.005) when the subjects were on their antidiabetic medications. During the trial off medication, 16 patients became symptomatic, with three of these developing symptoms severe enough to require hospitalization. It is apparent from this study that oral hypoglycemic medications can play a role in controlling symptoms in maturity-onset diabetic patients and that the beneficial effect of these agents on hyperglycemia may, in part, be explained by their stimulation of endogenous insulin secretion and partial suppression of endogenous glucagon.

Acute lymphoblastic leukemia. Association with vasopressin-responsive diabetes insipidus.

A rare case of acute lymphoblastic leukemia presenting with vasopressin-responsive diabetes insipidus (DI) is reported. The patient presented with polydypsia and polyuria of 9 L/day. Findings from special investigations of the CNS, including brain scan, computerized tomographic scan, EEG, and lumbar puncture were within normal limits. The patient's condition improved substantially after receiving vasopressin injections and later chlorpropamide. The incidence and underlying mechanism of this rare complication of acute leukemia are reviewed, and the response of DI to chlorpropamide is discussed briefly. In this patient it is presumed that the DI was caused by leukemic infiltration of the supraopticohypophyseal tract, posterior pituitary, or hypothalamus.

Clinical resistance to vasopressin. Detection of antibody by hemagglutination.

We describe a patient with hypothalamic diabetes insipidus who after 20 years became refractory to the effect of commercial vasopressin injection. Vasopressin antibodies were measured using a sensitive hemagglutination technique. Resistance was associated with a high titer of antibodies that disappeared once vasopressin therapy was withdrawn and the diabetes insipidus was controlled with chlorpropamide. Antibodies were also measured in four additional patients with diabetes insipidus while they were or were not receiving vasopressin. A patient who had received the drug for only two years already had a substantial titer of antibodies to vasopressin, but in this case the response to the hormone was not impaired.

Efficacy of indapamide in central diabetes insipidus.

BACKGROUND: Central diabetes insipidus (CDI) results from deficient vasopressin (antidiuretic hormone) secretion and causes polydipsia and polyuria. Desmopressin, a synthetic analog of vasopressin, is the drug of choice in the treatment of CDI, but in mild cases, there are alternative drugs that can be used, including chlorpropamide, carbamazepine, and thiazides. METHODS: In this study, we investigated the efficacy of treatment with indapamide, which is an antihypertensive diuretic oral agent, in 20 consecutive patients with CDI. The diagnosis of CDI was established by water-deprivation and vasopressin tests. Before the study, serum and urinary osmolality, daily urinary volume, and serum electrolyte levels were measured in all 20 patients. Indapamide (2.5 mg/d) was administered for 10 days, and then the investigations were performed again; for purposes of comparison, 250 mg/d of chlorpropamide was also administered to 11 of the 20 patients who had been given indapamide. RESULTS: Indapamide revealed a 40.56% +/- 9.70% (mean +/- SD) (range, 19.6%-55.0%) reduction in 24-hour urinary volume and an increase in urinary osmolality, as well as a decrease in serum osmolality, and was as effective as chlorpropamide (P<.05) in the treatment of CDI. CONCLUSION: Because of its low cost and lack of significant adverse effects, indapamide may be a suitable, easy-to-use alternative oral agent for some patients with CDI.

Medication compliance in non-insulin-dependent diabetes: a randomized comparison of chlorpropamide and insulin.

Medication compliance may be a problem in the management of patients with diabetes. Some physicians initially treat patients having non-insulin-dependent diabetes with oral sulfonylureas because they fear greater compliance problems with insulin therapy. We compared compliance with insulin and chlorpropamide in patients newly beginning medication for NIDDM. Seventy-seven adults with hyperglycemia despite diet therapy were randomly assigned to chlorpropamide or insulin. Compliance was measured four times over 24 wk. Patients then crossed over to the other medication and were followed for 24 additional weeks. Overall, there were no differences in compliance with the two medications in terms of percent of prescription used, proportion taking at least 80% of prescribed medication, self-report of medication or diet compliance, or protocol dropout rates. However, treatment satisfaction was higher with chlorpropamide, and most patients preferred chlorpropamide to insulin (P less than 0.0001). While such differences in satisfaction may affect long-term compliance, physicians should not assume that their patients will be less compliant with insulin than with oral sulfonylureas.

Comparison of chlorpropamide and glibenclamide treatment of maturity-onset diabetes: control assessed by fasting plasma glucose concentrations.

Twelve maturity-onset diabetic subjects were treated with chlorpropamide once daily, glibenclamide once daily, or glibenclamide twice daily in a crossover design study. Doses were increased until the fasting blood glucose concentrations became less than 6 mmol/L (108 mg/dl), at which time the patients were admitted for a 24-h study period. There was little difference between the plasma glucose and insulin responses to chlorpropamide or glibenclamide given twice daily (mean doses 489 and 11 mg/day, respectively). When glibenclamide was given once daily (mean dose 9 mg/day), similar plasma glucose concentrations during the day were obtained with slightly higher plasma glucose concentrations during the night. Four patients had chlorpropamide-induced flushing with alcohol, and six patients had postprandial hypoglycemia on glibenclamide. Chlorpropamide once daily or glibenclamide twice daily are suitable for control based on fasting blood glucose measurements.