Renal protection in hypertensive patients: selection of antihypertensive therapy

Combination of sacubitril/valsartan and blockade of the PI3K pathway enhanced kidney protection in a mouse model of cardiorenal syndrome

Aims

Angiotensin receptor-neprilysin inhibitor (ARNI) is an established treatment for heart failure. However, whether ARNI has renoprotective effects beyond renin-angiotensin system inhibitors alone in cardiorenal syndrome (CRS) has not been fully elucidated. Here, we examined the effects of ARNI on the heart and kidneys of CRS model mice with overt albuminuria and identified the mechanisms underlying ARNI-induced kidney protection.

Methods and results

C57BL6 mice were subjected to chronic angiotensin II infusion, nephrectomy, and salt loading (ANS); they developed CRS phenotypes and were divided into the vehicle treatment (ANS-vehicle), sacubitril/valsartan treatment (ANS-ARNI), and two different doses of valsartan treatment (ANS-VAL M, ANS-VAL H) groups. Four weeks after treatment, the hearts and kidneys of each group were evaluated. The ANS-vehicle group showed cardiac fibrosis, cardiac dysfunction, overt albuminuria, and kidney fibrosis. The ANS-ARNI group showed a reduction in cardiac fibrosis and cardiac dysfunction compared with the valsartan treatment groups. However, regarding the renoprotective effects characterized by albuminuria and fibrosis, ARNI was less effective than valsartan. Kidney transcriptomic analysis showed that the ANS-ARNI group exhibited a significant enhancement in the phosphoinositide 3-kinase (PI3K)-AKT signalling pathway compared with the ANS-VAL M group. Adding PI3K inhibitor treatment to ARNI ameliorated kidney injury to levels comparable with those of ANS-VAL M while preserving the superior cardioprotective effect of ARNI.

Conclusion

PI3K pathway activation has been identified as a key mechanism affecting remnant kidney injury under ARNI treatment in CRS pathology, and blockading the PI3K pathway with simultaneous ARNI treatment is a potential therapeutic strategy for treating CRS with overt albuminuria.

Effects of Genistein on Common Kidney Diseases

Genistein is a naturally occurring phytoestrogen (soy or soybean products) that is classified as an isoflavone, and its structure is similar to that of endogenous estrogens; therefore, genistein can exert an estrogen-like effect via estrogen receptors. Additionally, genistein is a tyrosine kinase inhibitor, which enables it to block abnormal cell growth and proliferation signals through the inhibition of tyrosine kinase. Genistein is also an angiogenesis inhibitor and an antioxidant. Genistein has effects on kidney cells, some of the kidney’s physiological functions, and a variety of kidney diseases. First, genistein exerts a protective effect on normal cells by reducing the inflammatory response, inhibiting apoptosis, inhibiting oxidative stress, inhibiting remodeling, etc., but after cell injury, the protective effect of genistein decreases or even has the opposite effect. Second, genistein can regulate renin intake to maintain blood pressure balance, regulate calcium uptake to regulate Ca²⁺ and Pi balances, and reduce vasodilation to promote diuresis. Third, genistein has beneficial effects on a variety of kidney diseases (including acute kidney disease, kidney cancer, and different chronic kidney diseases), such as reducing symptoms, delaying disease progression, and improving prognosis. Therefore, this paper reviews animal and human studies on the protective effects of genistein on the kidney in vivo and in vitro to provide a reference for clinical research in the future.

Association of Thiazide Use in Patients with Hypertension with Overall Fracture Risk: A Population-Based Cohort Study

Thiazide diuretics have long been widely used as antihypertensive agents. In addition to reducing blood pressure, thiazides also control calcium homeostasis and increase bone density. We hypothesized that the use of thiazides in patients with hypertension would reduce overall fracture risk. We used the Taiwan National Health Insurance Research Database to find patients with a hypertension diagnosis who accepted antihypertensive treatment from 2000 to 2017. The patients were further classified into thiazide users and nonthiazide users. Multivariable Cox regression analysis and Kaplan-Meier survival analysis were performed to estimate the adjusted hazard ratios (aHRs) and cumulative probability of fractures. After 1:1 propensity score matching by sex, age, urbanization level of place of residence, income, comorbidities, and medications, there were 18,483 paired thiazide users and non-users, respectively. The incidence densities of fractures (per 1000 person-months) were 1.82 (95% CI: 1.76-1.89) and 1.99 (95% CI: 1.92-2.06) in the thiazide and nonthiazide groups, respectively. The results indicated a lower hazard ratio for fractures in thiazide users (aHR = 0.93, 95% CI: 0.88-0.98). Kaplan-Meier survival analysis revealed a significantly lower cumulative incidence of fractures in the thiazide group (log-rank test; p = 0.0012). In conclusion, our results reveal that thiazide use can reduce fracture risk. When antihypertensive agents are being considered, thiazide may be a better choice if the patient is at heightened risk of fracture.

Combining Neprilysin Inhibitor With AT2R Agonist Is Superior to Combination With AT1R Blocker in Providing Reno-Protection in Obese Rats

Clinical use of the combination therapy of the neprilysin inhibitor sacubitril and angiotensin II type 1 receptor blocker valsartan is known to be associated with albuminuria. Albuminuria is both a risk factor for and an indicator of kidney injury. Earlier work from our laboratory reported that the agonist of angiotensin II type 2 receptor Compound 21 (C21) prevents proteinuria, albuminuria, and is reno-protective in obese Zucker rats fed high salt diet (HSD). Thus, we hypothesized that sacubitril/C21 combination provides superior reno-protection compared to sacubitril/valsartan. Male obese Zucker rats 10–11 weeks old were treated daily with vehicle, sacubitril + C21, or sacubitril + valsartan while fed HSD for 16 days. HSD-feeding caused kidney dysfunction, evident by significant increases in urinary protein, osteopontin, and cystatin C. HSD-feeding lowered plasma cystatin C and creatinine concentrations suggestive of hyperfiltration, which was not affected by either treatment. Unlike sacubitril/valsartan, sacubitril/C21 treatment significantly decreases proteinuria, albuminuria, the expression of nephrin, and kidney weight, independent of hyperfiltration, compared with HSD alone. Moreover, sacubitril/valsartan therapy increased plasma renin and did not prevent HSD-induced increases in renal angiotensin II, while sacubitril/C21 completely prevented these changes. Together, this study suggests that sacubitril/C21 afforded superior reno-protection compared to sacubitril/valsartan therapy in high salt-fed obese Zucker rats.

Combining mesenchymal stem cells with serelaxin provides enhanced renoprotection against 1K/DOCA/salt-induced hypertension

BACKGROUND AND PURPOSE

Fibrosis is a hallmark of chronic kidney disease (CKD) that significantly contributes to renal dysfunction, and impairs the efficacy of stem cell-based therapies. This study determined whether combining bone marrow-derived mesenchymal stem cells (BM-MSCs) with the renoprotective effects of recombinant human relaxin (serelaxin) could therapeutically reduce renal fibrosis in mice with one kidney/deoxycorticosterone acetate/salt (1K/DOCA/salt)-induced hypertension, compared with the effects of the ACE inhibitor, perindopril.

EXPERIMENTAL APPROACH

Adult male C57BL/6 mice were uni-nephrectomised and received deoxycorticosterone acetate and saline to drink (1K/DOCA/salt) for 21 days. Control mice were uni-nephrectomised but received water over the same time period. Sub-groups of 1K/DOCA/salt-injured mice (n = 5-8 per group) were treated with either serelaxin (0.5 mg·kg^-1 ·day^-1 ) or BM-MSCs (1 × 10⁶ per mouse) alone; both treatments combined (with 0.5 × 10⁶ or 1 × 10⁶ BM-MSCs per mouse); or perindopril (2 mg·kg^-1 ·day^-1 ) from days 14-21.

KEY RESULTS

1K/DOCA/salt-injured mice developed elevated BP and hypertension-induced renal damage, inflammation and fibrosis. BM-MSCs alone reduced the injury-induced fibrosis and attenuated BP to a similar extent as perindopril. Serelaxin alone modestly reduced renal fibrosis and effectively reduced tubular injury. Strikingly, the combined effects of BM-MSCs (at both doses) with serelaxin significantly inhibited renal fibrosis and proximal tubular epithelial injury while restoring renal architecture, to a greater extent than either therapy alone, and over the effects of perindopril.

CONCLUSION AND IMPLICATIONS

Combining BM-MSCs and serelaxin provided broader renoprotection over either therapy alone or perindopril and might represent a novel treatment for hypertensive CKD.

Pulse Pressure and the Risk of End-Stage Renal Disease Among Chinese Adults in Singapore: The Singapore Chinese Health Study

Background Although hypertension is an established risk factor for chronic kidney disease, less is known about the relationship of pulse pressure (PP), a measure of arterial stiffness, with chronic kidney disease. We investigated the association of systolic blood pressure (BP), diastolic BP, PP, and mean arterial pressure with the risk of end-stage renal disease (ESRD) in the prospective population-based Singapore Chinese Health Study. Methods and Results We used data from 30 636 participants who had BP measured at ages 46 to 85 years during follow-up I interviews between 1999 and 2004. Information on lifestyle factors was collected at recruitment from 1993 to 1998, and selected factors were updated at follow-up I. We identified 463 ESRD cases over an average 11.3 years of follow-up I by linkage with the nationwide Singapore Renal Registry. Cox proportional hazards regression models were used to assess the relations between different BP indexes and ESRD risk. Each BP index was positively associated with ESRD when studied individually. However, when PP was included as a covariate, systolic and diastolic BP and mean arterial pressure were no longer associated with ESRD. Conversely, PP remained significantly associated with ESRD risk in a dose-dependent manner (Ptrend<0.001) after adjusting for systolic or diastolic BP. Compared with the lowest group (<45 mm Hg) of PP, the hazard ratio was 5.25 (95% CI, 3.52-7.84) for the highest group (≥85 mm Hg). The association between hypertension and ESRD risk was attenuated and no longer significant after adjusting for PP. Conclusions Our findings provide a basis for targeting reduction of arterial stiffness to decrease ESRD risk.

Effect of angiotensin receptor blockers on blood pressure and renal function in patients with concomitant hypertension and chronic kidney disease: a systematic review and meta-analysis

Objective: Angiotensin receptor blockers (ARB) are among the recommended first-line treatment options in patients with hypertension and chronic kidney disease (CKD). This meta-analysis evaluated the effect of ARB on blood pressure (BP) and renal function in patients with concomitant hypertension and CKD with or without diabetes.Methods: Literature search was performed in PubMed/MEDLINE, EMBASE and BIOSIS to identify parallel-group, randomized controlled trials (≥8 weeks) reporting the effects of ARB on office systolic/diastolic BP (SBP/DBP), estimated glomerular filtration rate (eGFR), serum creatinine (SCr), creatinine clearance (CrCl) or proteinuria in adults with hypertension and CKD. Mean difference (MD, generic inverse variance) with 95% confidence intervals (CIs) was used to report an outcome.Results: Among the 24 studies identified, 19 evaluated ARB as monotherapy, 4 evaluated ARB as combination therapy and one evaluated ARB both as monotherapy and combination therapy. Median (range) duration of the studies was 12 (1.84-54.0) months. ARB monotherapy significantly (p < 0.01) reduced BP (treatment ≥1 year: SBP [MD: -14.84 mmHg; 95% CI: -17.82 to -11.85]/DBP [-10.27 mmHg; -12.26 to -8.27]) and proteinuria (≥1 year [-0.90 g/L; -1.22 to -0.59]). Results were consistent for combination therapy. In these studies, non-significant changes were observed for eGFR, CrCl and SCr. The impact of SBP changes on eGFR was not significant; however, studies were of a relatively short duration.Conclusion: ARB had a favorable impact on BP and renal parameters such as proteinuria with monotherapy as well as with combination therapy, highlighting their potential benefits in patients with hypertension and CKD. During the short follow-up of these studies, no significant change in eGFR was observed.

Pharmacokinetics, Safety and Tolerability of Tylerdipine Hydrochloride, a Novel Dihydropyridine Dual L/T-type Calcium Channel Blocker, after Single and Multiple Oral Doses in Healthy Chinese Subjects

BACKGROUND AND OBJECTIVE

Tylerdipine hydrochloride (KBP-5660) is a novel L/T-type dual calcium channel blocker developed for the treatment of hypertension. We aimed to study the pharmacokinetics, safety and tolerability of tylerdipine in healthy Chinese subjects.

METHODS

Two double-blind, randomized, dose-escalation studies were conducted that included a total of 88 healthy subjects: (1) a single-ascending dose (SAD) study; and (2) a multiple-ascending dose (MAD) study. In the SAD study, 64 subjects were randomly assigned to receive a single dose of 0.5, 2.5, 5, 10, 15, 20, 25, or 30 mg of tylerdipine or placebo. In the MAD study, 24 subjects were randomly assigned to receive 10 or 20 mg of tylerdipine or placebo once daily for 9 days. Blood samples were collected at the designated time points for pharmacokinetic analyses. Safety assessments were conducted throughout the study.

RESULTS

Following a single oral dose of tylerdipine of 5-30 mg, the mean maximum plasma concentration (C_max) increased from 0.9993 to 10.11 ng/ml; mean area under the plasma-concentration curve (AUC) from time zero to 72 h increased from 4.332 to 73.95 h·ng/ml. AUC increased in a greater than dose-proportional manner, whereas C_max exhibited a rough but non-typical dose-proportionality increase. In the MAD study, steady-state conditions were achieved after 1 week of daily dosing in both dose groups. Accumulation of tylerdipine was low, with accumulation ratios (R_AUC) of less than 1.65. All adverse events were assessed as mild or moderate.

CONCLUSION

Tylerdipine hydrochloride was safe and well tolerated. The exposure (AUC) of tylerdipine over the dose range of 5-30 mg increased in a greater than dose-proportional manner, while C_max exhibited a rough but non-typical dose proportionality increase. A slight accumulation of tylerdipine was observed following multiple dosing.

STUDY REGISTRATIONS

CTR20140862 and CTR20150660.

A critical review of adverse effects to the kidney: mechanisms, data sources, and in silico tools to assist prediction

INTRODUCTION

The kidney is a major target for toxicity elicited by pharmaceuticals and environmental pollutants. Standard testing which often does not investigate underlying mechanisms has proven not to be an adequate hazard assessment approach. As such, there is an opportunity for the application of computational approaches that utilize multiscale data based on the Adverse Outcome Pathway (AOP) paradigm, coupled with an understanding of the chemistry underpinning the molecular initiating event (MIE) to provide a deep understanding of how structural fragments of molecules relate to specific mechanisms of nephrotoxicity. Aims covered: The aim of this investigation was to review the current scientific landscape related to computational methods, including mechanistic data, AOPs, publicly available knowledge bases and current in silico models, for the assessment of pharmaceuticals and other chemicals with regard to their potential to elicit nephrotoxicity. A list of over 250 nephrotoxicants enriched with, where possible, mechanistic and AOP-derived understanding was compiled. Expert opinion: Whilst little mechanistic evidence has been translated into AOPs, this review identified a number of data sources of in vitro, in vivo, and human data that may assist in the development of in silico models which in turn may shed light on the interrelationships between nephrotoxicity mechanisms.

Renoprotective Effect of the Combination of Renin-angiotensin System Inhibitor and Calcium Channel Blocker in Patients with Hypertension and Chronic Kidney Disease

BACKGROUND

Renin-angiotensin system inhibitor and calcium channel blocker (CCB) are widely used in controlling blood pressure (BP) in patients with chronic kidney disease (CKD). We carried out a meta-analysis to compare the renoprotective effect of the combination of angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) and CCB (i.e., ACEI/ARB + CCB) with ACEI/ARB monotherapy in patients with hypertension and CKD.

METHODS

Publications were identified from PubMed, Embase, Medline, and Cochrane databases. Only randomized controlled trials (RCTs) of BP lowering treatment for patients with hypertension and CKD were considered. The outcomes of end-stage renal disease (ESRD), cardiovascular events, BP, urinary protein measures, estimated glomerular filtration rate (GFR), and adverse events were extracted.

RESULTS

Based on seven RCTs with 628 patients, ACEI/ARB + CCB did not show additional benefit for the incidence of ESRD (risk ratio [RR] = 0.84; 95% confidence interval [CI]: 0.52-1.33) and cardiovascular events (RR = 0.58; 95% CI: 0.21-1.63) significantly, compared with ACEI/ARB monotherapy. There were no significant differences in change from baseline to the end points in diastolic BP (weighted mean difference [WMD] = -1.28 mmHg; 95% CI: -3.18 to -0.62), proteinuria (standard mean difference = -0.55; 95% CI: -1.41 to -0.30), GFR (WMD = -0.32 ml/min; 95% CI: -1.53 to -0.89), and occurrence of adverse events (RR = 1.05; 95% CI: 0.72-1.53). However, ACEI/ARB + CCB showed a greater reduction in systolic BP (WMD = -4.46 mmHg; 95% CI: -6.95 to -1.97), compared with ACEI/ARB monotherapy.

CONCLUSION

ACEI/ARB + CCB had no additional renoprotective benefit beyond than what could be achieved with ACEI/ARB monotherapy.

Renal endothelial function is associated with the anti-proteinuric effect of ACE inhibition in 5/6 nephrectomized rats

In healthy rats, the physiological variation of baseline endothelial function of intrarenal arteries correlates with the severity of renal damage in response to a subsequent specific renal injury. However, whether such a variation in endothelial function may also condition or predict the variable response to angiotensin-converting enzyme-inhibiting treatment in these individuals has not been addressed before. To study this, 5/6 nephrectomy was performed to induce renal injury and chronic kidney disease in a group of healthy Wistar rats. At the time of nephrectomy, interlobar arteries were obtained from the extirpated right kidney and studied in vitro for endothelium-dependent relaxation to acetylcholine. Six weeks thereafter, treatment with lisinopril was started (n = 11) and continued for 9 wk. Proteinuria (metabolic cages) and systolic blood pressure (SBP; tail cuff) were evaluated weekly, and these were analyzed in relation to renal endothelial function at baseline. 5/6 Nephrectomy induced an increase in SBP and progressive proteinuria. Treatment with lisinopril reduced SBP and slowed proteinuria, albeit to a variable degree among individuals. The acetylcholine-induced renal artery dilation at baseline negatively correlated with lisinopril-induced reduction of proteinuria (r(2) = 0.648, P = 0.003) and with the decrease in SBP (r(2) = 0.592, P = 0.006). Our data suggest that angiotensin-converting enzyme-inhibitor attenuates the progression of renal damage the most in those individuals with decreased basal renal endothelial-mediated vasodilation.

Manidipine plus delapril in patients with Type 2 diabetes and hypertension: reducing cardiovascular risk and end-organ damage

In patients with hypertension and diabetes, atherothrombosis is a leading cause of morbidity and mortality, and there is now compelling evidence demonstrating that lowering elevated blood pressure (BP) is one of the most beneficial aims of therapy in this high-risk population. Indeed, major international guidelines have set a target BP goal of 130/80 mmHg in high-risk patients and recommend combination treatment with two or more drug classes to help achieve this objective. Manidipine plus delapril is a fixed-dose combination of a third-generation dihydropyridine calcium antagonist and an angiotensin-converting enzyme inhibitor, which is effective in mild-to-moderately hypertensive patients with an inadequate response to monotherapy. It is also effective in the long-term (50 weeks) management of essential hypertension. Comparative studies have demonstrated that manidipine plus delapril is as effective as enalapril plus hydrochlorothiazide (HCTZ) in patients with hypertension that is unresponsive to monotherapy, and as effective as ramipril plus HCTZ, valsartan plus HCTZ, irbesartan plus HCTZ and olmesartan plus HCTZ in patients with essential hypertension and Type 2 diabetes. In addition, manidipine plus delapril exhibited renoprotective effects in normotensive Type 2 diabetic patients, and improved fibrinolytic function (significantly more than irbesartan plus HCTZ) in hypertensive patients with Type 2 diabetes. Manidipine 10 mg plus delapril 30 mg once daily was generally well tolerated, with no unexpected adverse effects and evidence of a low incidence of ankle edema. Thus, manidipine plus delapril is a fixed-dose combination treatment that significantly reduces elevated BP with once-daily administration. It is well tolerated and has ancillary properties, such as nephroprotective activity and improvement of fibrinolytic balance, which may help reduce cardiovascular morbidity and mortality, particularly in high-risk patients, such as those with Type 2 diabetes mellitus.

Retrospective evaluation of adverse drug reactions induced by antihypertensive treatment

The use of cardiovascular drugs is related to the development of adverse drug reactions (ADRs) in about 24% of the patients in the Cardiovascular Care Unit. Here, we evaluated the ADRs in patients treated with antihypertensive drugs. The study was conducted in two phases: In the first phase, we performed a retrospective study on clinical records of Clinical Divisions (i.e., Internal Medicine Operative Unit and Geriatric Operative Unit) from January 1, 2012 to December 31, 2012. Moreover from January 1, 2013 to March 30, 2013 we performed a prospective study on the outpatients attending the Emergency Department (ED) of the Pugliese-Ciaccio Hospital of Catanzaro, by conducting patient interviews after their informed consent was obtained. The association between a drug and ADR was evaluated using the Naranjo scale. We recorded 72 ADRs in the Clinical Divisions and six in the ED, and these were more frequent in women. Using the Naranjo score, we showed a probable association in 92% of these reactions and a possible association in 8%. The most vulnerable age group involved in ADRs was that of the elderly patients. In conclusion, our results indicate that antihypertensive drugs may be able to induce the development of ADRs, particularly in elderly women receiving multiple drug treatment. Therefore, it is important to motivate the healthcare providers to understand their role and responsibility in the detection, management, documentation, and reporting of ADRs, as also all the essential activities for optimizing patient safety.

Elevated 18F-FDG levels in blood and organs after angiotensin II receptor blocker administration: experiment in mice administered telmisartan

Angiotensin II receptor blockers (ARBs) are a common treatment for hypertensive patients but affect renal function. In this study, the effects of ARB on (18)F-FDG distribution and excretion were examined in mice treated with telmisartan at different doses.

METHODS

Male C57BL/6J mice were given telmisartan (low-dose group, 0.33 mg/kg/d; moderate-dose group, 0.66 mg/kg/d; high-dose group, 3 mg/kg/d) mixed in a high-fat diet for 20 wk. Mice on a telmisartan-free diet served as the control. At designated time points, the mice were injected with (18)F-FDG (18.5 MBq/mouse, n = 5-10/time point for each group) to examine its biodistribution. Autoradiography using kidney sections was performed to visualize (18)F-FDG excretion. Plasma blood urea nitrogen (BUN) and creatinine levels were also measured to evaluate renal function.

RESULTS

Twenty-week telmisartan treatment significantly and dose-dependently increased (18)F-FDG levels in the blood (percentage injected dose per gram of tissue normalized by animal body weight: low, 0.13 ± 0.03 [P < 0.0083]; moderate, 0.15 ± 0.01 [P < 0.0083]; high, 0.15 ± 0.03 [P < 0.0083], vs. control, 0.09 ± 0.01). Significantly increased (18)F-FDG levels in organs were observed in mice in the moderate- and high-dose groups but not in the low-dose group. The plasma BUN and creatinine levels also dose-dependently increased, but they were within the reference ranges (for BUN: low, 27.00 ± 4.42 mg/dL; moderate, 28.40 ± 2.70 mg/dL; high, 39.22 ± 6.91 mg/dL [P < 0.0083], vs. control, 22.40 ± 2.80 mg/dL. For creatinine: low, 0.28 ± 0.11 mg/dL; moderate, 0.40 ± 0.07 mg/dL [P < 0.0083]; high, 0.51 ± 0.09 mg/dL [P < 0.0083], vs. control, 0.18 ± 0.04 mg/dL). The blood (18)F-FDG level positively correlated with plasma BUN (r = 0.48, P < 0.01) and creatinine (r = 0.61, P < 0.01) levels. The (18)F-FDG levels in the blood and organs returned to baseline 3 wk after cessation of telmisartan treatment. Autoradiography indicated that renal (18)F-FDG excretion was attenuated by telmisartan treatment and was reversed after treatment cessation.

CONCLUSION

(18)F-FDG levels in the blood and organs were significantly increased by telmisartan treatment, indicating a potential increase in background activity on PET imaging of patients treated with ARBs. Our findings indicate the need for a careful assessment of (18)F-FDG uptake in patients treated with ARBs. A brief cessation of ARB treatment may be a potential method to avoid these effects and solve this problem.

Further data on beta-blockers and cancer risk: observational study and meta-analysis of randomized clinical trials

BACKGROUND

The aim of the present paper is to provide some further data on the relationship between β-blocker treatment and the incidence of cancer, using two different approaches (epidemiological study and meta-analysis of clinical trials).

METHODS

In a consecutive series of 1340 diabetic patients starting insulin therapy, 112 cases of cancer during a mean follow-up of 75.9 months were identified as first hospital admission or death. For each case, the controls were chosen randomly from those members of the cohort matched for age, sex and BMI. The main predefined analysis was the comparison of cases and controls for length of exposure to β-blockers and proportion of patients exposed using a conditional logistic regression which takes into account the matching structure. For the meta-analytic sub-study, an extensive search of Medline and the Cochrane Library (any date up to December 31st, 2011) was performed for all trials in which a β-blocker was used. Mantel-Haenszel Odds Ratios (MH-OR) with 95% confidence intervals for incident malignancies were calculated using a random effect model.

RESULTS

After adjusting for mean daily dose of glargine and metformin, and ischemic heart disease, exposure to β-blockers was associated with a reduced overall risk of cancer (HR 0.33 [0.13; 0.83], p = 0.019; HR for each month of exposure 0.87 [0.77; 0.98], p = 0.025). In the meta-analysis sub-study, performed on nine trials, β-blockers were associated with a non-significant trend toward lower risk of cancer (MH-OR 0.93 [0.86; 1.01], p = 0.070).

STUDY LIMITATION

Limitations of the observational study are the small sample size that limits the statistical power of analyses, that it was performed on diabetic patients only, and that diagnoses of malignancies were derived from administrative data.

CONCLUSIONS

In conclusion, this research seem to confirm a possible beneficial effect of β-blockers against the risk of cancer development.

Renin-angiotensin system, hypertension, and chronic kidney disease: pharmacogenetic implications

About 80% of CKD (chronic kidney disease) patients are hypertensive, and kidney function and blood pressure are clearly related to both physiologic and pathologic conditions in a "vicious cycle". In this pathologic scenario, there is a renin-angiotensin system (RAS) hyperactivity associated to progression of renal damage. Current guidelines indicate as the first choice of antihypertensive intervention, the pharmacologic blockade of the RAS. Nonetheless, both response to treatment and renal protection have considerable inter-individual variability. The main aims of this review are to describe the genetic characteristics of RAS components and to identify the possible pharmacogenetic implications for RAS-blocker drugs in the hypertension-CKD scenario. To date, RAS polymorphisms have not been consistently associated to antihypertensive response and studies focusing on CKD are scarce. Nonetheless, pharmacogenetic studies for the RAS-blocker drugs could still be further explored, especially with new generation tools and focusing not only on the antihypertensive response, but also on renal protection as well.

Efficacy and safety of mycophenolate mofetil versus cyclophosphamide for induction therapy of lupus nephritis: a meta-analysis of randomized controlled trials

INTRODUCTION

Whether mycophenolate mofetil is superior to cyclophosphamide as induction therapy for lupus nephritis (LN) remains controversial.

OBJECTIVE

Our objective was to investigate the efficacy and safety of mycophenolate mofetil compared with cyclophosphamide as induction therapy for LN patients.

METHODS

Randomized controlled trials (RCTs) on humans were identified in searches of PubMed/MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials (all to 1 December 2011). Studies that compared the efficacy and safety between mycophenolate mofetil and cyclophosphamide as induction therapy in LN patients were selected. Methodological quality of the included trials was assessed according to Cochrane criteria and Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. The fixed effects model was applied for pooling where there was no significant heterogeneity, otherwise the random effects model (Dersimonian and Laird method) was performed.

RESULTS

Seven trials were identified, including 725 patients. The Dersimonian and Laird method was applied for renal remission in the presence of significant heterogeneity, and no statistically significant differences were distinguished between mycophenolate mofetil and cyclophosphamide. To explore the possible source of heterogeneity, meta-regression was performed. It was suggested that no obvious study- or patient-level factors could explain interstudy heterogeneity with statistical significance. Among all these factors, the mode of administration of cyclophosphamide could explain most of the heterogeneity, although the coefficient was insignificant. Therefore, we performed a sensitivity analysis by excluding the trial in which cyclophosphamide was administered orally instead of intravenously, which suggested that mycophenolate mofetil was more effective than intravenous cyclophosphamide for inducing complete remission (relative risk [RR] 1.72; 95% CI 1.17, 2.55; p = 0.006) and complete or partial remission (RR 1.18; 95% CI 1.04, 1.35; p = 0.01). In addition, mycophenolate mofetil was superior to cyclophosphamide for significantly reducing end-stage renal disease (ESRD) or death (RR 0.64; 95% CI 0.41, 0.98; p = 0.04). For the safety comparison, lower risks of leukopenia, amenorrhoea and alopecia, and a higher risk of diarrhoea were found with mycophenolate mofetil. No statistical differences in infection and gastrointestinal symptoms were distinguished between mycophenolate mofetil and cyclophosphamide. The relatively small number and the open-label fashion of eligible RCTs may limit the value of our meta-analysis.

CONCLUSIONS

Mycophenolate mofetil is superior to intravenous cyclophosphamide for inducing renal remission, and has a significant advantage over cyclophosphamide for reducing ESRD or death. Furthermore, mycophenolate mofetil has lower risks of leukopenia, amenorrhoea and alopecia, but a higher risk of diarrhoea than cyclophosphamide. However, our conclusions need to be proved further in larger well designed trials.

Secreted klotho and chronic kidney disease

Soluble Klotho (sKl) in the circulation can be generated directly by alterative splicing of the Klotho transcript or the extracellular domain of membrane Klotho can be released from membrane-anchored Klotho on the cell surface. Unlike membrane Klotho which functions as a coreceptor for fibroblast growth factor-23 (FGF23), sKl, acts as hormonal factor and plays important roles in anti-aging, anti-oxidation, modulation of ion transport, and Wnt signaling. Emerging evidence reveals that Klotho deficiency is an early biomarker for chronic kidney diseases as well as a pathogenic factor. Klotho deficiency is associated with progression and chronic complications in chronic kidney disease including vascular calcification, cardiac hypertrophy, and secondary hyperparathyroidism. In multiple experimental models, replacement of sKl, or manipulated up-regulation of endogenous Klotho protect the kidney from renal insults, preserve kidney function, and suppress renal fibrosis, in chronic kidney disease. Klotho is a highly promising candidate on the horizon as an early biomarker, and as a novel therapeutic agent for chronic kidney disease.

TRC120038, a Novel Dual AT(1)/ET(A) Receptor Blocker for Control of Hypertension, Diabetic Nephropathy, and Cardiomyopathy in ob-ZSF1 Rats

In hypertensive subjects, angiotensin II and endothelin participate in a manner involving closely interwoven pathways in increasing blood pressure (BP) and inducing end organ damage. The primary objective of this study was to determine the effect of TRC120038, a novel dual AT₁/ET_A receptor blocker on BP, in obese Zucker spontaneously hypertensive fatty rats (ob-ZSF1), an animal model of moderate hypertension, diabetes with progressive renal and cardiac dysfunction. Ob-ZSF1 rats loaded with 0.5% salt were treated with TRC120038 (11.8 mg/kg bid.) or candesartan cilexetil (0.3 mg/kg od.) or vehicle control. Blood pressure (by radio-telemetry) and renal functional markers were monitored throughout the study. Cardiac function was assessed terminally by pressure volume catheter. Markers for renal dysfunction were measured and changes were evaluated histopathologically. TRC120038 showed greater fall in both systolic and diastolic BP in comparison to candesartan at its maximum antihypertensive dose. TRC120038 also reduced the severity of renal dysfunction and preserved cardiac function in ob-ZSF1 rat.

Functional Importance of L- and P/Q-Type Voltage-Gated Calcium Channels in Human Renal Vasculature

Calcium channel blockers are widely used for treatment of hypertension, because they decrease peripheral vascular resistance through inhibition of voltage-gated calcium channels. Animal studies of renal vasculature have shown expression of several types of calcium channels that are involved in kidney function. It was hypothesized that human renal vascular excitation-contraction coupling involves different subtypes of channels. In human renal artery and dissected intrarenal blood vessels from nephrectomies, PCR analysis showed expression of L-type (Ca v 1.2), P/Q-type (Ca v 2.1), and T-type subtype (Ca v 3.1 and Ca v 3.2) voltage-gated calcium channels (Ca v s), and quantitative PCR showed highest expression of L-type channels in renal arteries and variable expression between patients of subtypes of calcium channels in intrarenal vessels. Immunohistochemical labeling of kidney sections revealed signals for Ca v 2.1 and Ca v 3.1 associated with smooth muscle cells of preglomerular and postglomerular vessels. In human intrarenal arteries, depolarization with potassium induced a contraction inhibited by the L-type antagonist nifedipine, EC 50 1.2×10 −8 mol/L. The T-type antagonist mibefradil inhibited the potassium-induced constriction with large variations between patients. Interestingly, the P/Q-type antagonist, ω-agatoxin IVA, inhibited significantly the contraction with 24% at 10 −9 mol/L. In conclusion L-, P/Q, and T-type channels are expressed in human renal blood vessels, and L- and P/Q-type channels are of functional importance for the depolarization-induced vasoconstriction. The contribution of P/Q-type channels to contraction in the human vasculature is a novel mechanism for the regulation of renal blood flow and suggests that clinical treatment with calcium blockers might affect vascular reactivity also through P/Q-type channel inhibition.

TRPC channel modulation in podocytes-inching toward novel treatments for glomerular disease

Glomerular kidney disease is a major healthcare burden and considered to represent a sum of disorders that evade a refined and effective treatment. Excellent biological and genetic studies have defined pathways that go awry in podocytes, which are the regulatory cells of the glomerular filter. The question now is how to define targets for novel improved therapies. In this review, we summarize critical points around targeting the TRPC6 channel in podocytes.

Treatment of bevacizumab-induced hypertension by amlodipine

BACKGROUND

Hypertension is a common toxicity of anti-VEGF agents, but its optimal treatment remains to define. This study aimed to describe the efficacy and tolerability of amlodipine, a calcium channel blocker, in patients with metastatic malignancies treated with bevacizumab, a humanized monoclonal antibody to VEGF.

PATIENTS AND METHODS

One hundred and eighty-seven patients with advanced or metastatic NSCLC, colorectal or ovarian cancer receiving bevacizumab (5 mg/kg every 2 weeks or 7.5 mg/kg every 3 weeks) and chemotherapy were eligible for this analysis. Blood pressure was measured at home twice daily according to international guidelines. Patients received amlodipine 5 mg daily for grade ≥ 2 bevacizumab-induced hypertension.

RESULTS

Twenty-six patients received amlodipine 5 mg daily for de novo hypertension (group A), and another 10 patients received amlodipine for exacerbation of previously existing hypertension (group B). Hypertension was controlled within 7 days under amlodipine in 23/26 (88.5%, 95%CI: 76.2-100) patients in group A, and 8/10 (80%, 95%CI: 55.2-100) patients in group B, with a favourable toxicity profile.

CONCLUSIONS

Amlodipine 5 mg daily appears safe and efficient for the treatment of hypertension in patients receiving bevacizumab at a dose-intensity of 2.5 mg/kg/week. Further prospective studies are warranted to confirm these results.

The effect of fat intake and antihypertensive drug therapy on serum lipid profile: a cross-sectional survey of serum lipids in male and female hypertensives

The present study aimed to investigate the effect of betablocker with diuretics therapy on serum cholesterol and high density lipoprotein (HDL-C) lipids in cross-sectional data (age, sex, weight, and body mass index (BMI), smoking/alcoholic consumption) and supplemented vegetarian low-fat diet with daily low fat energy intake, salt intake, duration of drug therapy, and serum protein as effective measures of lowering blood pressure among hypertensives in both males and females. Hypertensive patients on betablocker and/or thiazide therapy were compared in cross-section study with their age, blood pressure, fat intake, serum lipid profile, BMI, and serum albumin in males and females. Dietary fat intake and serum lipid profile were income related. Betablocker and diuretics therapy in combination with dietary fat intervention was beneficial for prolonged dyslipidemia control. Serum cholesterol level was main contributing factor dependent on BMI, duration of drug, and socio-economic factors. Fat intake contributed in hypertension and serum cholesterol levels. A cross-sectional data analysis showed beneficial effects of "low fat-salt-smoking-alcohol consumption and combined polyunsaturated fatty acid with antihypertensive therapy approach" to keep normal dyslipidemia and hypertension. Low fat intake, low salt, smoking, alcohol consumption, and combination of dietary oil supplements with lipid betablockers and diuretic modulators were associated with low hypertension and controlled dyslipidemia in Asian sedentary population.

Peptide hormone regulation of angiogenesis

It is now apparent that regulation of blood vessel growth contributes to the classical actions of hormones on development, growth, and reproduction. Endothelial cells are ideally positioned to respond to hormones, which act in concert with locally produced chemical mediators to regulate their growth, motility, function, and survival. Hormones affect angiogenesis either directly through actions on endothelial cells or indirectly by regulating proangiogenic factors like vascular endothelial growth factor. Importantly, the local microenvironment of endothelial cells can determine the outcome of hormone action on angiogenesis. Members of the growth hormone/prolactin/placental lactogen, the renin-angiotensin, and the kallikrein-kinin systems that exert stimulatory effects on angiogenesis can acquire antiangiogenic properties after undergoing proteolytic cleavage. In view of the opposing effects of hormonal fragments and precursor molecules, the regulation of the proteases responsible for specific protein cleavage represents an efficient mechanism for balancing angiogenesis. This review presents an overview of the actions on angiogenesis of the above-mentioned peptide hormonal families and addresses how specific proteolysis alters the final outcome of these actions in the context of health and disease.

Olmesartan medoxomil-induced acute renal failure in a premature newborn following maternal exposure during pregnancy: a case report and review of the literature

Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II (AT II) receptor blockers (ARBs) are widely used antihypertensives with well-recognized renoprotective and cardioprotective effects. Although treatment with these agents generally does not result in adverse metabolic consequences, their use during human pregnancy has been associated with negative reactions. Here we report a premature baby with a history of oligohydramnios and maternal exposure to the ARB olmesartan medoxomil who was transferred to our institution with acute renal failure. Conservative treatment with diuretics and meticulous management of fluids and electrolytes resulted in an improvement in renal function in the patient. We conclude that olmesartan medoxomil may cause reversible renal failure in premature neonates.

Possible new druggable targets for the treatment of nephrosis. Perhaps we should find them in caveolea?

Nephrosis refers to a condition resulting from proteinuric kidney disease, leading to irreversible renal parenchymal damage and end-stage renal disease when left untreated. Furthermore, nephrosis appears to be a communicable disease carrying risks and complications to other organs such as the heart. Key pathophysiolgical processes involved in initiating and progressing renal damage in nephrosis and its complications may include altered glomerular hemodynamics after initial renal damage and loss of nephrons, nephrotoxicity of increased renal protein traffic enforcing intrinsic 'common pathway' mechanisms of renal scarring, and generalized endothelial dysfunction proceeding CV disease. The reader is first provided a basic overview on key mechanisms, targets and therapies in nephrosis while referred to some excellent updates hereon for more detailed information. The broader purpose of this short review, however, is to highlight caveolae/caveolins and caveolar function as central modulators in all the above key processes of nephrosis. Caveolae - little caves in the plasma membrane that are particularly abundant in endothelial cells, amongst others - are now known to be involved not only in endothelial transcytosis (e.g. of albumin) but also in cholesterol homeostasis (LDL-transport) and, importantly, in signal transduction such as insulin signalling and nitric oxide signalling in endothelial function and regulation of vasomotor tone, as well as signalling by growth factor receptors - such as TGF-beta - which may participate in renal scarring. It is suggested that caveolae may represent crucial sites where possible new druggable targets in nephrosis may be found.

Avosentan reduces albumin excretion in diabetics with macroalbuminuria

Despite the first-line use of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), there is still a large need to improve the prevention and progression of diabetic nephropathy and its associated cardiovascular events. Endothelin antagonists have shown anti-inflammatory, antifibrotic, and antiproteinuric effects in experimental studies. This study was a randomized, placebo-controlled, double-blind, parallel-design, dosage-range study of the effect of the endothelin-A antagonist avosentan (SPP301) on urinary albumin excretion rate (UAER) in patients with diabetic nephropathy. We randomly assigned 286 patients with diabetic nephropathy, macroalbuminuria (UAER 0.2 to 5.6 mg/min), and BP <180/110 mmHg to 12 wk of avosentan (5, 10, 25, and 50 mg) or placebo, in addition to standard ACEI/ARB therapy. Relative to baseline, all avosentan dosages decreased mean relative UAER (-16.3 to -29.9%) compared with placebo (35.5%). Median relative UAER decreased with all avosentan dosages (-28.7 to -44.8%) compared with placebo (12.1%). Creatinine clearance and BP were unchanged at 12 wk. The main adverse events were peripheral edema (12%), mainly with high (>/=25 mg) dosages of avosentan; significant increases in liver enzymes did not occur. Twenty-one (7.3%) patients experienced adverse events that led to withdrawal from study medication. In summary, the endothelin-A antagonist avosentan given in addition to standard ACEI/ARB treatment decreases UAER in patients with diabetic nephropathy and macroalbuminuria.

Association between hypertensive urgencies and subsequent cardiovascular events in patients with hypertension

OBJECTIVE

To determine whether patients with hypertensive urgency have a higher risk for subsequent cardiovascular events compared with hypertensive patients without this event.

METHODS

Overall, 384 patients with hypertensive urgency and 295 control patients were followed up for at least 2 years. Hypertensive urgency was defined as a systolic blood pressure above 220 mmHg and/or a diastolic blood pressure above 120 mmHg without any evidence of acute end-organ damage. The control group consisted of patients admitted to the emergency department with a systolic blood pressure between 135 to 180 mmHg and a diastolic blood pressure between 85-110 mmHg. The number of cardiovascular events defined as acute coronary syndrome, acute stroke, atrial fibrillation, acute left ventricular failure and aortic aneurysm were consecutively analyzed during follow-up. The median follow-up time was 4.2 years (interquartile range 2.9-5.7 years). Twenty-six patients of the urgency group and 23 patients of the control group were lost for follow-up.

RESULTS

Overall, 117 (17%) patients had nonfatal clinical cardiovascular events and 13 had (2%) fatal cardiovascular events. The frequency of cardiovascular events was significantly higher in patients with hypertensive urgencies (88 vs. 42; P = 0.005). The Cox regression analysis identified age (P < 0.001) and hypertensive urgencies (P = 0.035) as independent predictors for subsequent cardiovascular events.

CONCLUSIONS

Hypertensive urgencies are associated with an increased risk for subsequent cardiovascular events in patients with arterial hypertension.

Immunogenicity of advanced glycation end products in diabetic patients and in nephropathic non-diabetic patients on hemodialysis or after renal transplantation

Advanced glycation end products (AGE) increase as a consequence of diabetic hyperglycemia and, in nephropathic patients, following renal function loss. Protein-bound AGE behave as immunogens, inducing formation of specific antibodies (Ab-AGE). In this work AGE immunogenicity was studied in 42 diabetic patients, 26 nephropathic patients on hemodialysis and 26 patients with end-stage renal disease who underwent kidney transplantation and in 20 normal subjects. Non-oxidation-derived AGE (nox-AGE), oxidation-derived AGE (ox-AGE) and Ab-AGE were measured by competitive or direct enzyme-linked immunosorbent assay (ELISA) and circulating immune complexes (CIC) by C1q ELISA. Nox- AGE increased significantly in all patient groups (p < or = 0.05 to < or = 0.0001) except in patients on hemodialysis for less than 6 yr. Ox-AGE were only significantly increased in patients transplanted more than 3 yr previously (p < 0.05). Ab-AGE were significantly lower than controls in both diabetic groups and in patients on hemodialysis for more than 6 yr (p < 0.005 to < 0.0001) and not unlike controls in the other groups. These results demonstrate that hemodialysis or renal transplantation can, initially, reduce either nox- or ox-AGE levels, which however go back to being high in time. Renal transplantation fails to normalize nox-AGE. More importantly, plasma Ab-AGE levels are reduced or unchanged in all patient groups in comparison with controls, despite higher circulating AGE levels. This suggests the importance of tissue-bound AGE as Ab-AGE targets. Additional interventions are needed to control AGE levels in treated nephropathic patients. The search and quantification of specific Ab-AGE would give more meaningful results if performed over specific tissue specimens.

Role of angiotensin-converting enzyme 2 and angiotensin(1-7) in 17beta-oestradiol regulation of renal pathology in renal wrap hypertension in rats

17beta-Oestradiol (E2)-mediated inhibition of angiotensin-converting enzyme (ACE) protects the E2-replete kidney from the progression of hypertensive renal disease. Angiotensin-converting enzyme 2 (ACE2), a homologue of ACE, counters the actions of ACE by catalysing the conversion of angiotensin II (Ang II) to angiotensin(1-7) [Ang(1-7)]. We investigated E2 regulation of ACE2 in the renal wrap (RW) model of hypertension in rats. After 6 weeks on a high-sodium diet (4% NaCl), the activity of ACE2 was reduced in the renal cortex by 31%, which was mirrored by similar decreases in ACE2 protein (30%) and mRNA expression (36%) in the ovariectomized RW rat (RW-OVX); E2 replacement prevented these effects. The RW-OVX rats exhibited greater renal injury, including 1.7-fold more tubulointerstitial fibrosis and 1.6-fold more glomerulosclerosis than E2-replete females (RW-Intact and RW-OVX+E2). Angiotensin(1-7) infusion prevented these exacerbating effects of ovariectomy on renal pathology; no differences in indicators of renal injury were observed between RW-OVX-Ang(1-7) and RW-Intact rats. These renal protective effects of Ang(1-7) infusion were not attributable to increased ACE2 activity or to changes in heart rate or body weight, since these parameters were unchanged by Ang(1-7) infusion. Furthermore, Ang(1-7) infusion did not attenuate renal injury by reducing mean arterial pressure (MAP), since infusion of the peptide did not lower MAP but rather caused a slight increase during a 6 week chronic treatment for Ang(1-7). These results suggest that E2-mediated upregulation of renal ACE2 and the consequent increased Ang(1-7) production contribute to E2-mediated protection from hypertensive renal disease. These findings have implications for E2-deficient women with hypertensive renal disease and suggest that therapeutics targeted towards increasing ACE2 activity and Ang(1-7) levels will be renal protective.

Complications of hypertension and the role of angiotensin receptor blockers in hypertension trials

Hypertension is a high-prevalence disease that may affect several organs. In recent years, data have accumulated indicating that angiotensin II receptor blockers (ARBs) may have a supplementary effect beyond lowering blood pressure. The aim of this review is to evaluate the impact of ARBs on the most important complications of hypertension--heart, cerebrovascular and renal diseases, and metabolic complications--based on the findings from large clinical hypertension trials. The results may indicate that ARBs have a superior effect compared with placebo or other antihypertensive drugs in order to prevent left ventricular hypertrophy, atrial fibrillation, stroke, renal disease and diabetes mellitus, while there appears to be no blood pressure-independent superior effect of ARBs regarding prevention of myocardial infarction or heart failure.

Hypertension and kidney protection in the elderly: what is the evidence in 2007?

Hypertension and diabetes mellitus are the two most widely recognized risk factors for cardiovascular disease (CVD), chronic kidney disease (CKD), and end-stage renal disease (ESRD) requiring dialysis/transplantation; both become increasingly important as one ages. Common pathways and mechanisms are involved in the development of renal vascular lesions in both conditions, and effective treatments for each are now available to reduce morbidity, mortality and progression of organ damage. Although this review will focus primarily on the ability to protect the kidney and vasculature elsewhere by lowering blood pressure in the elderly, other approaches, specifically dietary restriction of protein, strict control of diabetes mellitus, and the management of the different dyslipidemias, must be used in conjunction with the antihypertensive agents to obtain optimum protection.

Hypertension aggravates glomerular dysfunction with oxidative stress in a rat model of diabetic nephropathy

Oxidative stress may contribute to the pathogenesis of diabetic nephropathy (DN), although the detailed mechanism of reactive oxygen species (ROS) regulation is still unclear. This study examined the effect of high-salt diet on ROS production and expression of antioxidant enzymes in control and experimentally diabetic rats. Wistar fatty rats (WFR) as a type 2 diabetes mellitus model and Wistar lean rats (WLR) as a control were fed a normal-salt diet (NS) and high-salt diet (HS) from the age of 6 to 14 weeks. We then examined the blood pressure, urinary albumin excretion (UAE), and urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels. The expression of antioxidant enzymes including alpha-catalase (CAT), Cu-Zn superoxide dismutase (SOD), Mn SOD, and glutathione peroxidase (GPx) were analyzed in the glomeruli of the rats using Western blotting. The expression of NAD(P)H oxidase p47(phox) and NFkappaB p65 was evaluated using immunohistochemical staining. By 14 weeks of age, the WFR-HS group exhibited hypertension and markedly increased UAE. The level of 8-OHdG, a marker of oxidative damage, in the WFR-HS group was also higher than that in the WLR groups or WFR-NS group. The expression of alpha-CAT and Mn SOD proteins was significantly decreased in isolated glomeruli in the WFR-HS group. GPx and Cu-Zn SOD expression did not differ between the WFR and WLR groups. High expression of ROS and decreases in antioxidants were seen in the glomeruli of diabetic rats with hypertension, suggesting that oxidative stress may be involved in the development of DN.

Cardiovascular risk factors in hypertension: rationale and design of studies to investigate the effects of controlled-release carvedilol on regression of left ventricular hypertrophy and lipid profile

Patients at high risk for hypertension may require several therapeutic agents to lower their blood pressure to guideline-recommended targets. Some antihypertensive agents are more effective than others in protecting against cardiovascular morbidity and mortality. Numerous beta-blocking agents have been approved by the US Food and Drug Administration (FDA) for the treatment of hypertension. Previous trials have demonstrated that although all beta-blockers effectively reduce blood pressure, there are differences in how they affect various metabolic factors. In 2 trials, a novel controlled-release (CR) formulation of carvedilol will be tested against other selective beta-blockers to determine whether differences exist in their individual effects on cardiovascular risk factors. These will be the first head-to-head trials using carvedilol CR to determine whether the differing pharmacologic actions among beta-blockers result in varying effects on cardiovascular risk factors.

The effect of nimodipine on calcium homeostasis and pain sensitivity in diabetic rats

1. The pathogenesis of diabetic neuropathy is a complex phenomenon, the mechanisms of which are not fully understood. Our previous studies have shown that the intracellular calcium signaling is impaired in primary and secondary nociceptive neurons in rats with streptozotocin (STZ)-induced diabetes. Here, we investigated the effect of prolonged treatment with the L-type calcium channel blocker nimodipine on diabetes-induced changes in neuronal calcium signaling and pain sensitivity. 2. Diabetes was induced in young rats (21 p.d.) by a streptozotocin injection. After 3 weeks of diabetes development, the rats were treated with nimodipine for another 3 weeks. The effect of nimodipine treatment on calcium homeostasis in nociceptive dorsal root ganglion neurons (DRG) and substantia gelatinosa (SG) neurons of the spinal cord slices was examined with fluorescent imaging technique. 3. Nimodipine treatment was not able to normalize elevated resting intracellular calcium ([Ca(2+)]( i )) levels in small DRG neurons. However, it was able to restore impaired Ca(2+) release from the ER, induced by either activation of ryanodine receptors or by receptor-independent mechanism in both DRG and SG neurons. 4. The beneficiary effects of nimodipine treatment on [Ca(2+)]( i ) signaling were paralleled with the reversal of diabetes-induced thermal hypoalgesia and normalization of the acute phase of the response to formalin injection. Nimodipine treatment was also able to shorten the duration of the tonic phase of formalin response to the control values. 5. To separate vasodilating effect of nimodipine Biessels et al., (Brain Res. 1035:86-93) from its effect on neuronal Ca(2+) channels, a group of STZ-diabetic rats was treated with vasodilator - enalapril. Enalapril treatment also have some beneficial effect on normalizing Ca(2+) release from the ER, however, it was far less explicit than the normalizing effect of nimodipine. Effect of enalapril treatment on nociceptive behavioral responses was also much less pronounced. It partially reversed diabetes-induced thermal hypoalgesia, but did not change the characteristics of the response to formalin injection. 6. The results of this study suggest that chronic nimodipine treatment may be effective in restoring diabetes-impaired neuronal calcium homeostasis as well as reduction of diabetes-induced thermal hypoalgesia and noxious stimuli responses. The nimodipine effect is mediated through a direct neuronal action combined with some vascular mechanism.