Hemostatic concomitants of syndrome X

Effects of Doxazosin and Amlodipine on Mean Platelet Volume and Serum??Serotonin Level in Patients with??Metabolic Syndrome

BACKGROUND AND OBJECTIVE

In addition to reducing blood pressure, antihypertensive drugs should modify other atherosclerotic risk factors. One such risk factor is the prothrombotic state, which is characterised mainly by increased fibrinogen and plasminogen activator inhibitor-1 levels and abnormalities in platelet function. Platelet activity and aggregation potential can be estimated by measuring mean platelet volume (MPV). Serotonin plays a role in vasospasm and increased platelet aggregation capacity, and has been shown to increase MPV in vitro. However, serotonin levels and MPV have not been studied in the metabolic syndrome. We evaluated mean platelet volume (MPV) in patients with the metabolic syndrome, and compared the effects of doxazosin and amlodipine on MPV and serum serotonin level in patients with this condition.

METHODS

Thirty-eight patients who met the Adult Treatment Panel III criteria for the metabolic syndrome and 20 healthy controls were included in the study. Patients were randomised into two groups to receive doxazosin 4 mg/day (n=20) or amlodipine 10 mg/day (n=18). Patients' MPV, serum serotonin, insulin, insulin sensitivity, fasting blood glucose and lipid profiles were measured at baseline and after 8 weeks.

RESULTS

Patients with the metabolic syndrome had a significantly higher MPV compared with the control group. MPV was significantly decreased in the doxazosin-treated group (from 6.9 +/- 1.0 fL at baseline to 6.1 +/- 1.1 fL after treatment; p=0.02) but not in the amlodipine-treated group (6.8 +/- 0.9 fL at baseline vs 6.9 +/- 1.0 fL after treatment; p=0.9). Fasting blood glucose and total cholesterol were also significantly decreased compared with baseline in the doxazosin group. In the amlodipine group, there was a significant increase in serum serotonin levels and a decrease in serum insulin and improved insulin sensitivity.

CONCLUSION

In patients with the metabolic syndrome, doxazosin treatment not only decreases platelet activity, as measured by a change in MPV, but also improves metabolic abnormalities. Amlodipine also has beneficial effects in patients with the metabolic syndrome but has no effect on MPV.

Prediction and prevention of preeclampsia and IUGR

Preeclampsia, being one of the leading causes of maternal and perinatal morbidity and mortality, has been the subject of extensive research since its description. Preeclampsia has been called the disease of theories due to the enigma surrounding its exact pathophysiology. Despite the absence of treatment that reverses the disease process once started, screening for preeclampsia and intrauterine growth restriction (IUGR) has been a major clinical and research issue since the disease was first reported. This review evaluates the current evidence for prediction and prevention of preeclampsia and IUGR using clinical tests, maternal serum markers, and uterine artery Doppler screening. In addition, we critically evaluate the evidence regarding the different therapeutic strategies for the prevention of preeclampsia and IUGR and the latest clinical recommendations for their use.

Prediction of preeclampsia: can it be achieved?

In this review, the various biochemical tests that have been proposed for the prediction of preeclampsia are described and evaluated. Placenta hormone markers do not predict future disease. They denounce the early placental changes that are part of the evolving disease and only predict the imminent of preeclamptic syndrome. This explains why tests are better predictors when preeclampsia supervenes shortly, and why screening in the first trimester is unlikely to work as well as in the second trimester. The use of multiple markers in the screening should reflect different aspects of the disease process and could increase the specificity and sensitivity of the screening and work on different etiologic factors. The possible use of second-trimester biochemical screening to predict the risk of preeclampsia remains to be investigated in the high-risk population.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians

LEARNING OBJECTIVES

After completion of this article, the reader should be able to list the various theories on the etiology of preeclampsia, to relate the various risk factors for the development of preeclampsia, and to describe the various screening tests for preeclampsia.

Inhibitory effect of voglibose and gymnemic acid on maltose absorption in vivo

AIM: To determine whether diabetic care can be improved by combination of voglibose and gymnemic acid (GA), we compared the combinative and individual effects of voglibose and GA on maltose absorption in small intestine.

METHODS: The small intestine 30 cm long from 2 cm caudal ward Treitz’s ligament of Wistar rat was used as an in situ loop, which was randomly perfused in recircular mode with maltose (10 mmol/L) with or without different dosages of voglibose and/or GA for 1 h. To compare the time course, perfusion of 10 mmol/L maltose was repeated four times. Each time continued for 1 h and separated by 30 min rinse. In the first time, lower dosages of GA (0.5 g/L) and/or voglibose (2 μmol/L) were contained except control.

RESULTS: Absorptive rate of maltose was the lowest in combinative group (P < 0.05, ANOVA), for example, the inhibition rate was about 37% during the first hour when0.5 g/L-GA and 2 μmol/L voglibose with 10 mmol/L maltose were perfused in the loop. The onset time was shortened to 30 min and the effective duration was prolonged to 4 h with the combination; therefore the total amount of maltose absorption during the effective duration was inhibited more significantly than that in the individual administration (P < 0.05, U test of Mann Whitney). The effect of GA on absorptive barriers of the intestine played an important role in the combinative effects.

CONCLUSION: There are augmented effects of voglibose and GA. The management of diabetes mellitus can be improved by employing the combination.

Endothelial cell dysfunction and the pathogenesis of diabetic macroangiopathy

Type 2 diabetes mellitus (DM) represents a high risk condition for the development of atherosclerotic and thromboembolic macroangiopathy, which make major contributions to diabetic mortality and morbidity. While many cardiovascular risk factors are common to both atherosclerosis and Type 2 DM, the enhanced risk of diabetic macroangiopathy may be attributable to additional pro-atherogenic mediators associated with insulin resistance syndrome. Given the central pathogenic role of endotheliopathy in atherosclerosis, it is likely that this vascular monolayer is the ultimate target of injury in response to such mediators. Furthermore, a pro-oxidative, dysfunctional endothelium may actively contribute to the pro-atherogenic environment through an inappropriate regulation of vascular tone, permeability, coagulation, fibrinolysis, cell adhesion and proliferation. Such dysfunction may mediate hypertension, dyslipidaemia and altered haemostasis, in addition to aggravating in vivo insulin resistance.

Exploiting complementary therapeutic strategies for the treatment of type II diabetes and prevention of its complications

Impaired glycemic control in type II diabetes results from peripheral insulin resistance, hepatic insulin resistance, and a relative failure of beta cell function. Nutritional and pharmaceutical measures are now available for addressing each of these defects, presumably enabling a rational and highly effective clinical management of non-insulin-dependent diabetes mellitus. Peripheral insulin resistance, which usually responds to a very-low-fat diet, aerobic exercise training, and appropriate weight loss, can also treated with high-dose chromium picolinate, high-dose vitamin E, magnesium, soluble fiber, and possibly taurine; these measures appear likely to correct the diabetes-associated metabolic derangements of vascular smooth muscle, and thus lessen risk for macrovascular disease. Metformin's clinical efficacy is primarily reflective of reduced hepatic glucose output; this action should complement the benefits of peripheral insulin sensitizers. When these measures are not sufficient for optimal control, beta cell function can be boosted with second-generation sulfonylureas.

Up-regulation of IGF binding protein-1 as an anticarcinogenic strategy: relevance to caloric restriction, exercise, and insulin sensitivity

The mitotic rate of stem cells is a major determinant of cancer risk. Insulin-like growth factors (IGFs) are virtually obligate stimulants of cell turnover in nearly every tissue. IGF activity is subject to rapid modulation by hepatic release of IGF binding protein-1 (IGFBP-1), a factor whose synthesis is suppressed by insulin and increased by glucagon. Up-regulation of IGFBP-1 production can be expected to decrease IGF activity and thereby diminish cancer risk. Measures that sensitize peripheral tissues to insulin, and thereby down-regulate insulin secretion, can be expected to increase IGFBP-1 synthesis, provided that they do not unduly sensitize hepatocytes as well. Prolonged aerobic exercise and caloric restriction also increase IGFBP-1 production. Since IGF-1 suppresses hepatic synthesis of sex hormone binding globulin (SHBG), down-regulation of IGF activity will increase SHBG levels and thus diminish the availability of free sex hormones--an effect that should further decrease cancer risk in sex hormone-responsive tissues. These considerations rationalize many findings in animal and epidemiologic studies, and suggest that non-diabetic insulin resistance may be a significant cancer risk factor. Increased IGF activity associated with insulin resistance may also promote benign hyperplasias-most notably atherosclerosis. Hyperinsulinemia stimulates intimal hyperplasia indirectly, via IGF.

Up-regulation of intracellular signalling pathways may play a central pathogenic role in hypertension, atherogenesis, insulin resistance, and cancer promotion--the 'PKC syndrome'

The modern diet is greatly different from that of our paleolithic forebears' in a number of respects. There is reason to believe that many of these dietary shifts can up-regulate intracellular signalling pathways mediated by free intracellular calcium and protein kinase C, particularly in vascular smooth muscle cells; this disorder of intracellular regulation is given the name 'PKC syndrome'. PKC syndrome may entail either a constitutive activation of these pathways, or a sensitization to activation by various agonists. The modern dietary perturbations which tend to induce PKC syndrome may include increased dietary fat and sodium, and decreased intakes of omega-3 fats, potassium, calcium, magnesium and chromium. Insulin resistance may be both a cause and effect of PKC syndrome, and weight reduction and aerobic training should act to combat this disorder. PKC syndrome sensitizes vascular smooth muscle cells to both vasoconstrictors and growth factors, and thus promotes both hypertension and atherogenesis. In platelets, it induces hyperaggregability, while in the microvasculature it may be a mediator of diabetic microangiopathy. In vascular endothelium, intimal macrophages, and hepatocytes, increased protein kinase C activity can be expected to increase cardiovascular risk. Up-regulation of protein kinase C in stem cells may also play a role in the promotion of 'Western' fat-related cancers. Practical guidelines for combatting PKC syndrome are suggested.