Effects of blood pressure and the renin-angiotensin system on platelet activation in type 2 diabetes

Aims/Introduction:  Platelet‐derived microparticles (PDMP) are released from the platelets either after activation or in response to physical stimulation in vivo. The present study examined the association between blood pressure and PDMP, and the effects of high‐dose angiotensin receptor blockers (ARB) on PDMP in patients with type 2 diabetes.

Materials and Methods:  The study subjects consisted of 28 type 2 diabetes patients with blood pressure ≥130/80 mmHg who were treated with valsartan (80 mg daily). The patients were randomly assigned to take either 80 mg of telmisartan (Tel group) or 160 mg of valsartan (Val group) and then were followed up for 24 weeks. Thereafter, the patients were switched to combination therapy (5 mg of amlodipine with 40 mg of telmisartan [Tel group] or 80 mg of valsartan [Val group]) for 12 weeks.

Results:  Although the ambulatory blood pressure did not change, the PDMP levels were significantly decreased from baseline to week 24 (high dose ARB). In contrast, combination therapy reduced both blood pressure and PDMP levels compared with the baseline. Although the PDMP level was significantly correlated with the morning BP elevation at baseline and week 36 (combination therapy), this same relationship was not found at week 24. There were no significant differences in the blood pressure and PDMP levels between the two groups.

Conclusions:  Patients with morning hypertension might be at risk for cardiovascular diseases. High‐dose renin‐angiotensin system inhibition and blood pressure control are both considered to reduce cardiovascular events in patients with type 2 diabetes. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00048.x, 2010)

Enhanced sodium sensitivity and disturbed circadian rhythm of blood pressure in essential hypertension

OBJECTIVE

To assess whether an association between sodium-sensitive hypertension and metabolic syndrome exists; and whether, in patients with metabolic syndrome, the nocturnal fall of blood pressure decreases and salt restriction affects the circadian blood pressure rhythm.

METHODS

Japanese patients with essential hypertension, who were treated without any antihypertensive agent, were maintained on a high-sodium diet and a low-sodium diet for 1 week each. On the last day of each diet, the 24-h blood pressures were measured. A diagnosis of metabolic syndrome was made according to the International Diabetes Foundation definition

RESULTS

Among the 56 patients with essential hypertension, 15 patients were complicated with metabolic syndrome while 41 patients were not. The nocturnal blood pressure fall was significant in patients without metabolic syndrome, while it was not so in patients with metabolic syndrome. Only in patients with metabolic syndrome was the nocturnal blood pressure fall enhanced by sodium restriction. The prevalence of sodium-sensitive hypertension in patients with metabolic syndrome was significantly higher than in those without metabolic syndrome (70.6 versus 36.0%, respectively; P = 0.017). A multiple logistic regression analysis revealed central obesity to be an independent risk factor for sodium-sensitive hypertension (odds ratio, 1.41; 95% confidence interval, 1.04-1.91).

CONCLUSIONS

In patients with essential hypertension, an inter-relationship exists among metabolic syndrome, enhanced sodium sensitivity of the blood pressure and non-dipping. The elevated risk of cardiovascular diseases in patients with metabolic syndrome may be related to sodium-sensitive hypertension and non-dipping.

Benidipine Attenuates Glomerular Hypertension and Reduces Albuminuria in Patients with Metabolic Syndrome

Recent studies have shown that metabolic syndrome is associated with an increased risk for chronic kidney disease. We recently found that the prevalence of sodium-sensitive hypertension in patients with metabolic syndrome was significantly higher than that in patients with essential hypertension but without metabolic syndrome. We therefore assessed the effects of benidipine, a long-acting calcium channel blocker, on the sodium sensitivity of blood pressure and renal hemodymamics in 5 patients with metabolic syndrome. Glomerular hemodynamics were assessed using pressure-natriuresis curves, which were constructed by plotting the urinary excretion of sodium as a function of the mean arterial pressure, which was calculated as the mean of 48 values based on 24-h monitoring, during the intake of low (3 g NaCl daily) and relatively high (10 g NaCl daily) sodium diets. Under the relatively high sodium diet condition, benidipine significantly lowered systolic and diastolic blood pressure. The pressure-natriuresis curve was steeper after the administration of benidipine. Benidipine lowered glomerular capillary hydraulic pressure (P(GC)) levels (from 54.4+/-7.5 to 47.0+/-7.0 mmHg, p=0.0152) and reduced both the resistance of the afferent arterioles (from 10,338+/-2,618 to 9,026+/-2,627 dyn.s/cm5, p=0.047) and the resistance of the efferent arterioles (from 4,649+/-2,039 to 2,419+/-2,081 dyn.s/cm(5), p=0.003). The urinary albumin excretion rate also decreased after the administration of benidipine. These findings indicated that benidipine may be effective for reducing the risk of developing chronic kidney disease in patients with metabolic syndrome.

Glucocorticoid-induced diabetes mellitus: prevalence and risk factors in primary renal diseases

BACKGROUND/AIMS

In patients with primary renal diseases the current knowledge of hyperglycemia associated with corticosteroid therapy is limited. We therefore examined the prevalence and risk factors of glucocorticoid-induced diabetes mellitus (DM) in primary renal diseases.

METHODS

Patients were recruited with primary renal diseases who were started on corticosteroids between April 2002 and June 2005. In patients with DM, an impaired fasting glucose level and/or positive urinary glucose analyses before corticosteroids therapy were excluded.

RESULTS

During corticosteroid therapy (initial dose: prednisolone 0.75 +/- 0.10 mg/kg/day), DM was newly diagnosed in 17 (40.5%) of 42 patients. All of the 17 patients were diagnosed as having DM by postprandial hyperglycemia at 2 h after lunch, although they had normal fasting blood glucose levels. Age (OR 1.40, 95% CI 1.06-1.84) and body mass index (OR 1.87, 95% CI 1.03-3.38) were determined as independent risk factors for glucocorticoid-induced DM.

CONCLUSION

Over 40% of patients with primary renal disease developed DM during treatment with corticosteroids. A high age and high body mass index are the independent risk factors for glucocorticoid-induced DM. 24-hour urinary glucose analyses and postprandial plasma glucose are useful for detecting glucocorticoid-induced DM.