Glucocorticoid-induced renal vasodilatation is mediated by a direct renal action involving nitric oxide

The Impact of Glucocorticoid Therapy on Guideline-Directed Medical Treatment Titration in Patients Hospitalized for Heart Failure with Low Blood Pressure: A Retrospective Study

Background

Positive inotropic and renal protective actions of glucocorticoids have been observed clinically. Therefore, glucocorticoids may be used in patients with heart failure and low blood pressure (HF-LBP).

Methods

The medical records of 144 consecutive patients with HF-LBP who received glucocorticoids as an adjunctive treatment to facilitate the up-titration of β-blocker and angiotensin-converting enzyme inhibitor were reviewed.

Results

After four weeks of treatment, the metoprolol and captopril (or equivalent) dosages were progressively and consistently increased from 25 (interquartile range [IQR] = 12.5-75 mg/day) to 100 mg/day (IQR = 50-178.8 mg/day) and from 0 (IQR = 0-25 mg/day) to 12.5 mg/day (IQR = 0-50 mg/day), respectively. There was a remarkable beneficial hemodynamic response to the glucocorticoid treatment signified by an increase in blood pressure and decrease in heart rate. The average heart rate decreased by 6 beat per minute (bpm) (0.5-16 bpm), and the mean arterial blood pressure increased from 74.06 ± 7.81 to 78.85 ± 7.91 mmHg. We also observed an improvement in renal function and an increased diuretic response following glucocorticoid treatment. As a result, the left ventricular ejection fraction increased from 28.92 ± 8.06% to 33.86 ± 8.76%, and the diuretic response increased from 776.7 mL/40 mg furosemide (IQR = 133.8-2000 mL) to 4000 mL/40 mg furosemide on day 28 (IQR = 2200-5925 mL).

Conclusion

The use of glucocorticoid treatment to maintain hemodynamic and renal functional targets when titrating guideline-directed medical treatment in patients with HF-LBP may be safe, effective, and feasible.

Inflammation in Human Heart Failure: Major Mediators and Therapeutic Targets

Inflammation has been recognized as a major pathophysiological contributor to the entire spectrum of human heart failure (HF), including HF with reduced ejection fraction, HF with preserved ejection fraction, acute HF and cardiogenic shock. Nevertheless, the results of several trials attempting anti-inflammatory strategies in HF patients have not been consistent or motivating and the clinical implementation of anti-inflammatory treatments for HF still requires larger and longer trials, as well as novel and/or more specific drugs. The present work reviews the different inflammatory mechanisms contributing to each type of HF, the major inflammatory mediators involved, namely tumor necrosis factor alpha, the interleukins 1, 6, 8, 10, 18, and 33, C-reactive protein and the enzymes myeloperoxidase and inducible nitric oxide synthase, and their effects on heart function. Furthermore, several trials targeting these mediators or involving other anti-inflammatory treatments in human HF are also described and analyzed. Future therapeutic advances will likely involve tailored anti-inflammatory treatments according to the patient's inflammatory profile, as well as the development of resolution pharmacology aimed at stimulating resolution of inflammation pathways in HF.

Associations Between CYP17A1 and SERPINA6/A1 Polymorphisms, and Cardiometabolic Risk Factors in Black South Africans

Research in European and Asian populations has reported associations between single nucleotide polymorphisms (SNPs) in CYP17A1 and SERPINA6/A1 and circulating glucocorticoid concentrations, and some key cardiometabolic risk factors. This study aimed to investigate these associations in black South African adults, who are disproportionally affected by the metabolic syndrome and its related cardiometabolic risk factors. The dataset included black South African adults (n = 4,431; 56.7% women) from the AWI-Gen study, genotyped on the H3A genotyping array and imputed using the African reference panel at the Sanger imputation service. From the imputed data, 31 CYP17A1 SNPs and 550 SERPINA6/A1 SNPs were extracted. The metabolic syndrome and its components were defined using the 2009 harmonized guidelines. Serum glucocorticoid concentrations were measured in a subset of 304 men and 573 women, using a liquid chromatography-mass spectrometry method. Genetic associations were detected using PLINK. Bonferroni correction was used to control for multiple testing. A SNP at SERPINA6/A1, rs17090691 (effect allele G), was associated with higher diastolic blood pressure (BP) in all adults combined (p = 9.47 × 10-6). Sex-stratified analyses demonstrated an association between rs1051052 (effect allele G), another SERPINA6/A1 SNP, and higher high-density lipoprotein (HDL) cholesterol concentrations in women (p = 1.23 × 10-5). No association was observed between these variants and glucocorticoids or between any of the CYP17A1 SNPs and metabolic outcomes after adjusting for multiple testing. Furthermore, there were no associations between any of the SNPs tested and the metabolic syndrome. This study reports novel genetic associations between two SNPs at SERPINA6/A1 and key cardiometabolic risk factors in black South Africans. Future replication and functional studies in larger populations are required to confirm the role of the identified SNPs in the metabolic syndrome and assess if these associations are mediated by circulating glucocorticoids.

Glucocorticoids associate with cardiometabolic risk factors in black South Africans

Circulating glucocorticoids are associated with metabolic syndrome and related cardiometabolic risk factors in non-Africans. This study investigated these associations in Africans, whose metabolic phenotype reportedly differs from Europeans. Adiposity, blood pressure, glycaemia, insulin resistance, and lipid profile, were measured in 316 African men and 788 African women living in Soweto, Johannesburg. The 2009 harmonized criteria were used to define metabolic syndrome. Serum glucocorticoids were measured using liquid chromatography-mass spectrometry. Cortisol was associated with greater odds presenting with metabolic syndrome (odds ratio (95% CI) =1.50 (1.04, 2.17) and higher systolic (beta coefficient, β (95% CI) =0.04 (0.01, 0.08)) and diastolic (0.05 (0.02, 0.09)) blood pressure, but higher HDL (0.10 (0.02, 0.19)) and lower LDL (-0.14 (-0.24, -0.03)) cholesterol concentrations, in the combined sample of men and women. In contrast, corticosterone was only associated with higher insulin sensitivity (Matsuda index; 0.22 (0.03, 0.41)), but this was not independent of BMI. Sex-specific associations were observed, such that both cortisol and corticosterone were associated with higher fasting glucose (standardized β (95% CI): 0.24 (0.12, 0.36) for cortisol and 0.12 (0.01, 0.23) for corticosterone) and HbA1c (0.13 (0.01, 0.25) for cortisol and 0.12 (0.01, 0.24) for corticosterone) in men only, but lower HbA1c (0.10 (-0.20, -0.01) for cortisol and -0.09 (-0.18, -0.03) for corticosterone) in women only. Our study reports for the first time that associations between circulating glucocorticoid concentrations and key cardiometabolic risk factors exhibit both glucocorticoid- and sex-specificity in Africans.

Glucocorticoids Reverse Diluted Hyponatremia Through Inhibiting Arginine Vasopressin Pathway in Heart Failure Rats

Background

Arginine vasopressin dependent antidiuresis plays a key role in water‐sodium retention in heart failure. In recent years, the role of glucocorticoids in the control of body fluid homeostasis has been extensively investigated. Glucocorticoid deficiency can activate V2R (vasopressin receptor 2), increase aquaporins expression, and result in hyponatremia, all of which can be reversed by glucocorticoid supplement.

Methods and Results

Heart failure was induced by coronary artery ligation for 8 weeks. A total of 32 rats were randomly assigned to 4 groups (n=8/group): sham surgery group, congestive heart failure group, dexamethasone group, and dexamethasone in combination with glucocorticoid receptor antagonist RU486 group. An acute water loading test was administered 6 hours after drug administration. Left ventricular function was measured by a pressure‐volume catheter. Protein expressions were determined by immunohistochemistry and immunoblotting. The pressure‐volume loop analysis showed that dexamethasone improves cardiac function in rats with heart failure. Western blotting confirmed that dexamethasone remarkably reduces the expressions of V2R, aquaporin 2, and aquaporin 3 in the renal‐collecting ducts. As a result of V2R downregulation, the expressions of glucocorticoid regulated kinase 1, apical epithelial sodium channels, and the furosemide‐sensitive Na‐K‐2Cl cotransporter were also downregulated. These favorable effects induced by dexamethasone were mostly abolished by the glucocorticoid receptor inhibitor RU486, indicating that the aforementioned effects are glucocorticoid receptor mediated.

Conclusions

Glucocorticoids can reverse diluted hyponatremia via inhibiting the vasopressin receptor pathway in rats with heart failure.

Dexamethasone-induced diuresis is associated with inhibition of the renin-angiotensin-aldosterone system in rats

In heart failure (HF) patients, diuretics remain the cornerstone of therapy to relieve fluid retention. However, the resulting volume loss activates the renin-angiotensin-aldosterone system (RAAS), which blunts the decline in volume depletion and blood pressure. RAAS activation, in turn, compromises the diuretic decongesting effect. Although corticosteroids can induce potent diuresis in HF patients, the effects of corticosteroids on RAAS activation remain unclear. Therefore, we assessed the effects of dexamethasone (Dex) on urine output and plasma angiotensin II and aldosterone levels in rats following water deprivation-induced dehydration, following induction of chronic HF (CHF), and following induction of CHF and volume expansion therapy. In the dehydration model, Dex significantly increased urine output and inhibited dehydration-induced RAAS activation. This favorable effect was abolished by the glucocorticoid receptor antagonist RU486, suggesting involvement of the glucocorticoid receptor. In the CHF model, Dex treatments doubled urine output without activating RAAS. Moreover, in acute volume expansion experiments, Dex pretreatments led to potent diuresis during the pretreatment period and restored renal adaptation to acute volume expansion without activating RAAS in rats with CHF. Collectively, these data show that corticosteroids induce potent diuresis without activating RAAS in rats.

Physiology of Kidney Renin

The protease renin is the key enzyme of the renin-angiotensin-aldosterone cascade, which is relevant under both physiological and pathophysiological settings. The kidney is the only organ capable of releasing enzymatically active renin. Although the characteristic juxtaglomerular position is the best known site of renin generation, renin-producing cells in the kidney can vary in number and localization. (Pro)renin gene transcription in these cells is controlled by a number of transcription factors, among which CREB is the best characterized. Pro-renin is stored in vesicles, activated to renin, and then released upon demand. The release of renin is under the control of the cAMP (stimulatory) and Ca2+(inhibitory) signaling pathways. Meanwhile, a great number of intrarenally generated or systemically acting factors have been identified that control the renin secretion directly at the level of renin-producing cells, by activating either of the signaling pathways mentioned above. The broad spectrum of biological actions of (pro)renin is mediated by receptors for (pro)renin, angiotensin II and angiotensin-( 1 – 7 ).

Is race a risk factor for the development of renal artery stenosis?

Atherosclerotic renal artery disease is a common cause of hypertension and chronic kidney disease that may progress into end stage renal failure if not diagnosed and treated early. Renal artery stenosis (RAS) has been shown to be an independent risk factor for mortality in patients with coronary artery disease. We sought to determine whether race is an independent risk factor for developing RAS. A retrospective study was conducted including 324 patients with resistant hypertension who underwent renal angiography with or without coronary angiography. In univariate analysis, Caucasian race was associated with significant risk of RAS (OR = 2.3, P = .01). However, this association was no longer significant after correcting for additional clinical variables in a multivariate model (OR = 1.5, P = .07). There was a strong association between smoking and RAS (OR 2.0, P = .02). We conclude that traditional risk factors, especially smoking, rather than race, are the most important predictors of RAS development.

Potent diuretic effects of prednisone in heart failure patients with refractory diuretic resistance

BACKGROUND

Refractory congestive heart failure (CHF) with diuretic resistance is life-threatening and predicts a short life expectancy. Glucocorticoids have been proven to have potent diuretic effects in animal studies; however, their efficacy in CHF patients with diuretic resistance is not known.

METHODS

Thirteen CHF patients with significant volume overload and diuretic resistance who failed to respond to a conventional sequential nephron blockade therapeutic strategy; that is, the coadministration of a thiazide (hydrochlorothiazide) and spironolactone, in combination with loop diuretics, were studied. Prednisone (1 mg/kg daily) was then added to standard care, with other medications unchanged, to determine diuretic efficacy in these CHF patients. Variables included body weight, urine volume, serum electrolytes and renal function.

RESULTS

Adding prednisone resulted in striking diuresis with a mean (+/- SD) body weight reduction of 9.39+/-3.09 kg. Prednisone significantly decreased serum creatinine by 52.21+/-48.68 mumol/L and increased glomerular filtration rate by 33.63+/-15.87 mL/min/1.73 m(2) compared with baseline. All patients were discharged from hospital with improved clinical status and renal function, and 11 patients remained alive in the long term. The main side effect of prednisone appeared to be hyperglycemia in diabetic patients.

CONCLUSIONS

The present study demonstrated that prednisone can rapidly eliminate volume overload and improve clinical status and renal function in CHF patients with diuretic resistance. Further prospective randomized clinical studies are warranted to confirm its clinical efficacy.

Acute intrarenal administration of cortisol has no effect on renal blood flow in hypertensive individuals

BACKGROUND

Cortisol is known to increase blood pressure. One possible mechanism is the reported increase in renal vascular resistance (RVR). It is unknown whether this is due to a direct effect of cortisol on the kidneys.

OBJECTIVE

To study the effect of infusion of cortisol directly into the renal artery on renal blood flow (RBF) and on renal 11beta-hydroxysteroid dehydrogenase (11beta-HSD)-mediated conversion of cortisol to cortisone in patients with primary hypertension.

DESIGN AND METHODS

Twenty-seven patients with primary hypertension participated in this study. Fifteen received placebo and 12 received glycyrrhetinic acid (GRA; 500 mg) orally 2.5 h before the study. After a 10 min infusion of 5% glucose, cortisol was infused in stepwise increasing doses (0.625, 1.25 and 2.5 microg/kg per min), for 10 min each dose. At the end of each infusion step, RBF was measured using the xenon-133 washout technique. Plasma samples from the femoral artery and renal vein were taken for measurement of cortisol and cortisone. Urine was collected for measurement of steroid concentrations for 6 h on the day before the infusion and for 6 h after the infusion.

RESULTS

After placebo or GRA, cortisol infusion did not change RVR, RBF or blood pressure. RVR values were 0.72 (0.45-0.89) mmHg/ml per min per 100 ml tissue [median (first and third quartiles)] and 0.71 (0.64-0.91) mmHg/ml per min per 100 ml tissue during infusion of 5% glucose and infusion of the highest dose of cortisol, respectively ( P= NS). Cortisol infusion increased the venous-arterial difference in plasma cortisone concentration across the kidney from 76 (40-115) nmol/l to 138 (100-186) nmol/l (P< 0.05) and increased the cortisol : cortisone ratios in the renal vein and in urine (both P< 0.05). As compared with placebo, administration of GRA increased the cortisol : cortisone ratios in peripheral and renal veins and in the urine.

CONCLUSION

Acute infusion of cortisol in high doses directly into the renal artery in patients with primary hypertension did not affect RBF or RVR. Infusion of cortisol resulted in increased cortisol-cortisone conversion by renal 11beta-HSD2, but the concurrent increase in renal and urinary cortisol : cortisone ratio suggests a relative insufficiency of renal 11beta-HSD2 activity as a result of enzyme saturation. This may enhance mineralocorticoid receptor stimulation by cortisol.