Best Strategies for Hypertension Management in Type 2 Diabetes and Obesity

Insulin resistance, dyslipidemia, hypertension, obesity, cardiovascular disease, and chronic kidney disease cluster together, and the incidence of all of these disease states is increasing throughout the world. Current strategies for hypertension management—including the use of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, calcium antagonists, and thiazide diuretics—are effective for most patients. However, as the incidence of hypertension increases in this target population, so does that of resistant hypertension. As such, significant research and effort must be put forth to bring blood pressure to goal and delay or prevent target organ damage. Such efforts should frequently include a dihydropyridine calcium channel blocker such as amlodipine. Other agents that are currently underused in this population for the treatment of resistant hypertension include nebivolol, carvedilol, aliskiren, and aldosterone antagonists. Finally, significant potential is seen for darusentan, an endothelin antagonist, if it comes to market.     

Race and Financial Strain are Independent Correlates of Sleep in Midlife Women: The SWAN Sleep Study

Study Objectives:

To examine racial differences in sleep in a large cohort of midlife women and to evaluate whether indices of socioeconomic status (SES) are associated with racial differences in sleep.

Design:

Cross-sectional study.

Setting:

Participants'' homes.

Participants:

Caucasian (n = 171), African American (n = 138) and Chinese women (n = 59).

Interventions:

None.

Measurements:

Sleep quality was assessed with the Pittsburgh Sleep Quality Index. Polysomnographically assessed sleep duration, continuity, architecture, and NREM electroencephalograhic (EEG) power were calculated over multiple nights. Sleep disordered breathing and periodic leg movements were measured on a separate night. Linear regression analysis was used to model the independent and synergistic effects of race and SES on sleep after adjusting for other factors that impact sleep in midlife women. Indices of SES were self-reported educational attainment and financial strain.

Results:

Sleep was worse in African American women than Caucasian participants as measured by self-report, visual sleep stage scoring, and NREM EEG power. Slow wave sleep differences were also observed between Chinese and Caucasian participants. Racial differences persisted after adjustment for indices of SES. Although educational attainment was unrelated to sleep, financial strain was associated with decreased sleep quality and lower sleep efficiency. Financial strain-by-race interactions were not statistically significant, suggesting that financial strain has additive effects on sleep, independent of race.

Conclusions:

Independent relationships between race and financial strain with sleep were observed despite statistical adjustment for other factors that might account for these relationships. Results do not suggest that assessed indices of SES moderate the race-sleep relationship, perhaps due to too few women of low SES in the study.

Citation:

Hall MH; Matthews KA; Kravitz HM; Gold EB; Buysse DJ; Bromberger JT; Owens JF; Sowers M. Race and financial strain are independent correlates of sleep in midlife women: the SWAN sleep study. SLEEP 2009;32(1):73-82.     

Mice lacking Smad3 are protected against cutaneous injury induced by ionizing radiation

Transforming growth factor-beta (TGF-beta) plays a central role in the pathogenesis of inflammatory and fibrotic diseases, including radiation-induced fibrosis. We previously reported that mice null for Smad3, a key downstream mediator of TGF-beta, show accelerated healing of cutaneous incisional wounds with reduced inflammation and accumulation of matrix. To determine if loss of Smad3 decreases radiation-induced injury, skin of Smad3+/+ [wild-type (WT)] and -/- [knockout (KO)] mice was exposed to a single dose of 30 to 50 Gy of gamma-irradiation. Six weeks later, skin from KO mice showed significantly less epidermal acanthosis and dermal influx of mast cells, macrophages, and neutrophils than skin from WT littermates. Skin from irradiated KO mice exhibited less immunoreactive TGF-beta and fewer myofibroblasts, suggesting that these mice will have a significantly reduced fibrotic response. Although irradiation induced no change in the immunohistochemical expression of the TGF-beta type I receptor, the epidermal expression of the type II receptor was lost after irradiation whereas its dermal expression remained high. Primary keratinocytes and dermal fibroblasts prepared from WT and KO mice showed similar survival when irradiated, as did mice exposed to whole-body irradiation. These results suggest that inhibition of Smad3 might decrease tissue damage and reduce fibrosis after exposure to ionizing irradiation.     

Mitochondrial biogenesis in the metabolic syndrome and cardiovascular disease

The metabolic syndrome is a constellation of metabolic disorders including obesity, hypertension, and insulin resistance, components which are risk factors for the development of diabetes, hypertension, cardiovascular, and renal disease. Pathophysiological abnormalities that contribute to the development of the metabolic syndrome include impaired mitochondrial oxidative phosphorylation and mitochondrial biogenesis, dampened insulin metabolic signaling, endothelial dysfunction, and associated myocardial functional abnormalities. Recent evidence suggests that impaired myocardial mitochondrial biogenesis, fatty acid metabolism, and antioxidant defense mechanisms lead to diminished cardiac substrate flexibility, decreased cardiac energetic efficiency, and diastolic dysfunction. In addition, enhanced activation of the renin–angiotensin–aldosterone system and associated increases in oxidative stress can lead to mitochondrial apoptosis and degradation, altered bioenergetics, and accumulation of lipids in the heart. In addition to impairments in metabolic signaling and oxidative stress, genetic and environmental factors, aging, and hyperglycemia all contribute to reduced mitochondrial biogenesis and mitochondrial dysfunction. These mitochondrial abnormalities can predispose a metabolic cardiomyopathy characterized by diastolic dysfunction. Mitochondrial dysfunction and resulting lipid accumulation in skeletal muscle, liver, and pancreas also impede insulin metabolic signaling and glucose metabolism, ultimately leading to a further increase in mitochondrial dysfunction. Interventions to improve mitochondrial function have been shown to correct insulin metabolic signaling and other metabolic and cardiovascular abnormalities. This review explores mechanisms of mitochondrial dysfunction with a focus on impaired oxidative phosphorylation and mitochondrial biogenesis in the pathophysiology of metabolic heart disease.     

Accuracy of six commercially available systems for identification of members of the family vibrionaceae

Six commercially available bacterial identification products were tested with Vibrio alginolyticus (12 strains), V. cholerae (30 strains), Photobacterium (Vibrio) damselae (10 strains), V. fluvialis (10 strains), V. furnissii (4 strains), V. hollisae (10 strains), V. metschnikovii (9 strains), V. mimicus (10 strains), V. parahaemolyticus (30 strains), and V. vulnificus (10 strains) to determine the accuracy of each system for identification. The products included API 20E, Crystal E/NF, MicroScan Neg ID2 and Rapid Neg ID3, and Vitek GNI+ and ID-GNB. Each product was tested only with those species that were listed in its database. Overall, the systems correctly identified 63.9, 80.9, 63.1, 73.6, 73.5, and 77.7% of the isolates to species level, respectively. Error rates ranged from 0.8% for the API 20E to 10.4% for the Rapid Neg ID3. The API 20E gave "no identification" for 13.1% of the isolates, while the Neg ID2, GNI+, ID-GNB, and Crystal were unable to identify 1.8, 2.9, 5.0, and 6.9%, respectively. For V. cholerae, specifically, accuracy ranged from 50.0 to 96.7%, with the API 20E having the worst performance and Crystal having the best. V. fluvialis presented the biggest challenge for the API 20E and the GNI+, with probabilities averaging 10%, while V. mimicus was a major problem with the Crystal E/NF, which identified none of the strains correctly. With the Neg ID2, correct answers were often obtained only after a modified inoculation of the panel with a bacterial suspension prepared with 0.85% NaCl. Additional tests required for identification often included growth in the absence of NaCl, which is not readily available in most clinical laboratories. The only product to correctly identify at least 90% of V. cholerae strains was the Crystal E/NF, and only three of the six products, the API 20E and both of the Vitek cards, correctly identified more than 90% of the V. parahaemolyticus strains. Thus, extreme care must be taken in the interpretation of answers from these six commercially available systems for the identification of Vibrio species.     

Irbesartan/HCTZ fixed combinations in patients of different racial/ethnic groups with uncontrolled systolic blood pressure on monotherapy

The IrbesartaN/hydroChlorothiazide (HCTZ) bLood pressUre reductionS In diVErse patient populations (INCLUSIVE) trial was a multicenter, prospective, open-label, single-arm study evaluating the efficacy and safety of irbesartan/HCTZ fixed combinations in patients > or = 18 years old with uncontrolled systolic blood pressure (SBP, 140-159 mmHg; 130-159 mmHg for type-2 diabetes mellitus patients) after > or = 4 weeks of antihypertensive monotherapy. This analysis focused on different racial/ethnic subgroups. Treatment was sequential: placebo (4-5 weeks), HCTZ 12.5 mg (two weeks), irbesartan/HCTZ 150/12.5 mg (eight weeks) and irbesartan/HCTZ 300/25 mg (eight weeks). Overall, 515 Caucasians, 191 African Americans and 119 Hispanics/Latinos completing placebo treatment were enrolled. Mean SBP changes from baseline (placebo treatment end) to week 18 were -21.5 +/- 13.8 mmHg for Caucasians, -20.7 +/- 16.5 mmHg for African Americans and -22.9 +/- 13.2 mmHg for Hispanics/Latinos, respectively (p<0.001 for each). Mean diastolic BP (DBP) changes were statistically significant (p<0.001) and similar among racial/ethnic subgroups. By week 18, 70% (95% CI, 66%, 74%) of Caucasian, 66% (95% CI, 59%, 74%) of African-American and 65% (95% CI, 57%, 74%) of Hispanic/Latino patients achieved dual SBP/DBP goal. Treatments appeared to be well tolerated. In conclusion, irbesartan/HCTZ treatment provided SBP/DBP goal attainment in approximately two-thirds of Caucasian, African-American and Hispanic/Latino patients with SBP uncontrolled on antihypertensive monotherapy.     

Relation between lipids and atherosclerosis: epidemiologic evidence and clinical implications

Coronary artery disease (CAD) is the leading cause of death in most developed countries. Therefore, elucidation of risk factors and associated mechanisms for CAD has been a high priority. Data from the Framingham Heart Study and other large-scale epidemiologic studies have identified major risk factors associated with CAD, demonstrating the adverse effects of increased total and low-density lipoprotein cholesterol levels and the protective effect of high-density lipoprotein cholesterol. Other more recent investigations, including the Lipid Research Clinics Trial and the Helsinki Heart Study, have shown that lowering total cholesterol and raising high-density lipoprotein cholesterol significantly reduce the risk for CAD. Because hypertension is also a significant risk factor for CAD, the assumption has been that blood pressure reduction should offer significant benefits in terms of CAD risk. However, despite their antihypertensive efficacy, diuretics and beta blockers have failed to significantly reduce CAD morbidity or mortality. The adverse effects of these antihypertensive agents on lipid profiles, glucose metabolism and other metabolic parameters may account for their disappointing performance in reducing CAD morbidity and mortality. As a result, newer agents such as angiotensin-converting enzyme inhibitors and calcium antagonists that appear to be free of such adverse effects have garnered considerable attention for their potential to reduce CAD risk.     

Plasma aldosterone and corticosterone responses to adrenocorticotropin, angiotensin, potassium, and stress in spontaneously hypertensive rats

The responses of plasma aldosterone and corticosterone to ACTH, angiotensin II (AII), and potassium chloride (KCl) infusion and the aldosterone, corticosterone and PRA responses to immobilization stress were studied in 2-month-old spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto (WKY) normotensive controls. Basal levels of plasma aldosterone and corticosterone were greater and PRA was less in the SHR than in the WKY. Aldosterone and corticosterone responses to graded AII were similar in both groups. Aldosterone and corticosterone responses to graded doses of KCl and ACTH, however, were significantly greater in SHR than in WKY normotensive rats. Plasma corticosterone, PRA, and aldosterone responses to immobilization stress were reduced in SHR compared to WKY. At 2 months of age, blood pressure was definitely elevated in SHR and was associated with low PRA and relatively high basal levels of aldosterone and corticosterone. Discordance between the renin-angiotensin system and mineralocorticoid secretion in the SHR may be due to enhanced adrenal sensitivity to factors such as ACTH and potassium. Suppressed PRA in SHR may be due, in part, to increased mineralocorticoid secretion, resulting in sodium retention and intravascular volume expansion.     

Obesity, cardiometabolic syndrome, and chronic kidney disease: the weight of the evidence

The epidemic of obesity experienced in both industrialized and nonindustrialized countries largely accounts for the increase in the prevalence of the cardiometabolic syndrome (CMS). Obesity and the CMS significantly increase the risk for cardiovascular disease (CVD) and chronic kidney disease (CKD). Multiple abnormalities that can lead to kidney injury have been identified in overweight and obese people, including insulin resistance, compensatory hyperinsulinemia, inappropriate activation of the renin-angiotensin-aldosterone system and increased oxidative stress, endoplasmic reticulum stress, coagulability, and impaired fibrinolysis. The combined effects of these conditions induce in the kidneys impaired pressure natriuresis, glomerular hypertension, endothelial dysfunction, and vasoconstriction, as well as matrix proliferation and expansion. Among the consequences are microalbuminuria, now known to be a surrogate of diffuse endothelial dysfunction as well as a predictor of CVD, and CKD. Diet and regular physical activity are the cornerstones of weight management, and they add to currently available pharmacologic agents and bariatric surgery. The understanding of the pathophysiology of obesity/CMS helps to explain the benefits of agents that improve insulin sensitivity, control inflammation, and block the renin-angiotensin-aldosterone system. The increasing prevalence of obesity and CMS contribute to the growing frequency of CKD and demands the development of multifactorial strategies directed at identifying people at risk, as well as preventing excessive weight gain and its deleterious consequences.     

Increased plasma nitric oxide, L-arginine, and arginase-1 in cirrhotic patients with progressive renal dysfunction

Background and Aims:  Increased levels of nitric oxide (NO) are hypothesized to contribute to renal dysfunction in patients with decompensated cirrhosis. In this study, we examined whether splanchnic and/or peripheral NO levels and L-arginine (L-Arg) correlate with progressive renal dysfunction in cirrhotics.
Methods:  Serum NO metabolites (NOx) and L-Arg were measured in: controls ( n  = 10); organ donors ( n  = 12); compensated cirrhotics ( n  = 17), cirrhotics with ascites ( n  = 25), refractory ascites ( n  = 11) or hepatorenal syndrome type II (HRS) ( n  = 11) and chronic renal failure patients ( n  = 18).
Results:  Plasma NOx and L-Arg levels rose progressively with worsening renal function in decompensated cirrhotics. Both NOx and L-Arg levels were highest in patients with HRS ( P  < 0.001 and P  < 0.025, respectively). While there were no differences in NOx levels related to the site of sampling, L-Arg levels were lowest in hepatic venous blood. There were significant relationships of NOx and L-Arg with Model for End-Stage Liver Disease score and Child–Pugh scores ( P  < 0.04 and P  < 0.01, respectively). Multivariate analysis showed a significant relationship between NOx, L-Arg and HRS.
Conclusion:  Worsening renal function in decompensated cirrhosis is accompanied by progressive elevation in plasma NOx and L-Arg. These findings support the hypothesis that NO-mediated vasodilation is probably linked with the mechanism of progressive renal failure in decompensated cirrhotics.