Iranian Journal of Diabetes and Metabolism
Year:2003 | Volume:2 | Issue:2|Papers Count:11

Insulin resistant states are emerging rapidly and lots of efforts have gone into understanding their pathogenesis and major metabolic consequences. Hypertriglyceridemia, a major complication of this metabolic syndrome, seems to be caused by overproduction of lipoproteins (LPs) containing apo B that are rich in triglycerides. Some in vitro and in vivo models have been introduced so as to understand mechanisms governing lipid metabolism in insulin resistance states. Human and animal studies have suggested a key role for overproduction of VLDL in hypertriglyceridemia and dyslipidemic states. Recently, we have employed a diet-induced animal model of insulin resistance (hamster fed with fructose) in our laboratory in order to examine the relationship among development of insulin resistant state, impaired metabolism of LPs and overproduction of LPs containing apo B. These experiments have indicated that insulin resistant states occur along with overproduction of VLDL containing apoBI05 from liver and enteral LPs rich in apo B 48. In insulin resistant states, decreased metabolic signaling to liver and intestine seems to play a critical role in overproduction of LPs. We have also been recognized a number of intracellular factors which may regulate VLDL production. This article reviews recent advances in the area; the hypothesis indicating that a complex interaction exist between increased free fatty acids flow from peripheral tissues to the liver and intestine (caused by hyperinsulinemia) and prolonged lipogenesis has also been expounded.      

Diabetes mellitus is characterized by several adverse consequences among which diabetic foot is a major complication. With a life long incidence of 15%, diabetic foot is accountable for more than 50% of non-traumatic lower limb amputations. Regular care, proper footwear and early treatment, but, have proved effective measures in preventing such outcome. The problem and features as infection, ulceration, or gangrene. Neuropathy, poor circulation, and decreased resistance to infection are the three major contributors to the development of diabetic foot; which when present, foot deformities or minor trauma can readily lead to ulceration and infection. Not all diabetic foots are preventable, but appropriate preventive measures can dramatically reduce their occurrence.      

Background: A controversy exists on the prevalence of hearing impairment in diabetic patients. Previous studies have reported figures ranging from 0 to 93%. Methods: 80 diabetic patients (mean age: 49.08±16; range: 16-65 years) were evaluated with regards to their hearing thresholds, using pure tone and speech audiometry. The results were compared with 78 healthy controls. None of the patients or controls reported histories on exposures that might affect their hearing power. Results: For all frequencies, lower hearing thresholds were registered in diabetic patients (on average 5.74±1.8 dB) compared to the controls. In sum, 53.7% of diabetics showed hearing thresholds lower than controls. Diabetics had poorer speech discrimination function but equal speech reception as compared to the controls. Age seemed to influence the mode of hearing impairment in the diabetic patients. To say, high frequencies disturbances were more commonly affected in older diabetics the reverse was true for the younger ones. Genders, duration of diabetes and positive family history for diabetes were not related to the degree of hearing impairment. Patients with retinopathy had poorer hearing threshold. Conclusion: Hearing loss seems to be a frequent feature of diabetes mellitus.      

Background: Diabetes type 1 is characterized by autoimmune destruction or primary dysfunction of pancreatic β cells. The more common form is the autoimmune type, which can be associated with other endocrine malfunction such as adrenal insufficiency and Hashimoto' s thyroiditis. Autoimmune thyroiditis is characterized by presence of anti TG, anti TPO and anti TSH antibodies in the plasma. This study has investigated the prevalence of autoimmune thyroid disorders in type 1 diabetic patients. Methods: 200 type 1 diabetics and 200 age/sex matched non-diabetic controls were recruited. Blood samples were taken to determine serum levels of thyroid hormones (T3RU, T3, T4, and TSH) and antithyroid antibodies. Results: TG-Ab and TPO-Ab levels were significantly higher (P<0.001) in diabetics compared to controls (mean TG-Ab: 955.7±495.5in diabetics and 451.0±189.5in controls; mean TPO-Ab: 463.2±182.3in diabetics and 112.4±38.3in controls). Clinical and subclinical hyperthyroidism was four times more common in diabetics. Conclusion: It seems reasonable that type 1 diabetic patients, especially those at younger ages, be screened for thyroid hormones and anti-thyroid antibodies.    

Background: Diabetes mellitus, the most common metabolic disorder of childhood, has important physical and emotional complications; this urges the role of patient education and self- monitoring. Diabetes is costly since patients have to do several lab tests and spend a lot on treatment. Methods: 150 patients with IDDM entered this cross-sectional study. The metabolic control and degree to which these patients were utilizing available facilities were determined and compared with same surveys from Germany, France, USA, Australia, and Saudi Arabia. Results: 91.3% of patients had no glucometer thus were unable to do self-monitoring. HbA1C had been regularly determined in only 8.66%. Insulin therapy was improper or inadequate in 59.1%. The quality of metabolic control was significantly poorer than the other mentioned nations (p< 0.001). Conclusion: The study advocates educational programs for diabetics. Complete insurance coverage and free weekly lab tests are also suggested.    

Background: Risk factors of cardiovascular disorders have been the subject of several studies. Recently, simultaneous high waist circumference (WC) and high serum triglyceride (Tg) has been proposed as a simple screening measure to predict non-traditional risk factors. This study has looked at the risk factors of cardiovascular disorders present in subjects with this phenotype. Methods: Non diabetic females of age 18-65 years who had been enrolled in the Tehran Lipid and Glucose Study (TLGS) were recruited. Based on fasting Tg and WC, subjects fell into four categories: TgHWH (Tg>160 mg/dl, WC>80 cm), TgHWL (Tg>160 mg/dl, WC<80 cm), TgLWH (Tg<160 mg/dl, WC>80 cm) and TgLWL (Tg<160 mg/dl, WC<80 cm). Cardiovascular risk factors including lipid profiles and anthropometric variables were compared between the categories. The prevalence of hypertension, LDL-C>130 mg/dl, total cholesterol>220 mg/dl and HDL- C<45 mg/dl were also determined in each category. Results: 5630 subjects were studied. TgLWL and TgHWH constituted to 27.5 % and 31.9 % of subjects, respectively. Mean age of subjects dropping in TgLWL, TgLWH, TgHWL and TgHWH groups was 28±10, 39+12, 36+12 and 46±11, respectively and TgHWH subjects were significantly older than other groups (p<.001). Systolic and diastolic blood pressures, body mass index and WC were significantly higher in TgHWH. Significantly higher levels of total cholesterol, triglycerides and LDL-C and significantly lower level of HDL-C were found in the TgHWH group. The prevalence of subjects with four or more risk factors was 61.4% in TgHWH versus 1% in TgLWL group. Conclusion: Parallel high waist circumference and high serum triglycerides (TgHWH) can find use as a simple screening measure to predict other risk factors of cardiovascular disorders.      

Background: Early detection of carbohydrate intolerance is important to prevent maternal and perinatal complications. This study aims to determine association of symptoms and clinical feature with different degree of carbohydrate intolerance in comparison with healthy pregnant women. Methods: Two thousand four hundred sixteen pregnant women referred to five university hospital clinics were followed up until delivery. Previously known diabetic patients were excluded from the study. The universal screening was performed with a 50-g 1-hour glucose challenge test (GCT). Those with plasma glucose ≥130mg/dl underwent a 100-g 3-hour glucose tolerance test (GTT) to diagnose gestational diabetes mellitus (GDM) according to Carpenter and Coustan criteria. Also based on result of GCT and GTT all pregnancy divided to four groups GDM, impaired GCT (IGCT), impaired GTT (IGT) and normal pregnancy. Family and obstetric histories were taken followed by a complete physical examination included: BMI and blood pressure measurements, excess weight gain during pregnancy, proteinuria, glycosuria, polyhydramnios, and edema. Symptoms were considered were as followed: polyuria, polydipsia. Results: Among the 2416 pregnant women, 114(4.7) were diagnosed with GDM. Of the 114, 42 (36.8%) were obese, 39 (34.2%) had glycosuria, 5 (4.3%) had pre-eclampsia, 22 (19.2%) had abnormal excess weight gain during pregnancy. The most important symptoms were polyuria (14.9%), polydipsia (12.6%). In comparison with healthy group, GDM patients had a significantly higher BMI, glycosuria, polyhydramnios, proteinuria, and excess weight gain. Association of these symptoms in GDM patients was significantly different from that in healthy pregnant women. Out of 114 GDM patients 59 (51.7%) did not have any symptoms or any abnormal clinical features. Conclusion: The rate 0 f a symptomatic patient in different level of carbohydrat intolerance indicates that symptom - based screening would miss many subjects. Despite clinical feature is not a reliable basis for screening GDM patients, it maybe used to improve maternal surveillance.      

Background: LDL oxidation plays a significant role in atherosclerosis process. Change in LDL type, occurring with physical activity, and the resulting decrease in LDL sensitivity to the oxidative rocess can protect the subject against atherosclerosis. This study has compared LDL sensitivity to oxidation in athletes and non athletes. Methods: 14 male athletes (aged 48±2) and 14 male non athletes (aged 44±4) were recruited. 10 ml venous fasting blood was obtained from each subject. According to the PURL guidelines, LDL sensitivity to oxidation was evaluated using conjugated diene method. Cholesterol and triglyceride were measured by enzymatic immunoassay. HDL-c was measured by precipitation method. LDL was calculated by Fried-Wald formula. Results: LDLs from athletes' sera were less vulnerable to oxidation than non-athletes' sera. To say, mean lag time in athletes was 60.35±10compared to 56±10 in non athletes. This difference, however, was not statistically significant. A significant difference existed between the two groups with regard to HD L-c level (46.2±8 vs. 38±8.5; P<0. 05). Conclusion: The experimental evidences suggest that oxidation of LDL paves the way to atherosclerosis. There are also reports on the role of physical activities in preventing atherosclerosis development. However, other factors, such as serum concentration of vitamin E, composition of LDLs, can influence the atherosclerosis process and their roles should not be neglected.