Pathologic Basis and Treatment Considerations in Chronic Kidney Disease-Related Hypertension

Hypertension in chronic kidney disease: What lies behind the scene

Hypertension is a frequent condition encountered during kidney disease development and a leading cause in its progression. Hallmark factors contributing to hypertension constitute a complexity of events that progress chronic kidney disease (CKD) into end-stage renal disease (ESRD). Multiple crosstalk mechanisms are involved in sustaining the inevitable high blood pressure (BP) state in CKD, and these play an important role in the pathogenesis of increased cardiovascular (CV) events associated with CKD. The present review discusses relevant contributory mechanisms underpinning the promotion of hypertension and their consequent eventuation to renal damage and CV disease. In particular, salt and volume expansion, sympathetic nervous system (SNS) hyperactivity, upregulated renin–angiotensin–aldosterone system (RAAS), oxidative stress, vascular remodeling, endothelial dysfunction, and a range of mediators and signaling molecules which are thought to play a role in this concert of events are emphasized. As the control of high BP via therapeutic interventions can represent the key strategy to not only reduce BP but also the CV burden in kidney disease, evidence for major strategic pathways that can alleviate the progression of hypertensive kidney disease are highlighted. This review provides a particular focus on the impact of RAAS antagonists, renal nerve denervation, baroreflex stimulation, and other modalities affecting BP in the context of CKD, to provide interesting perspectives on the management of hypertensive nephropathy and associated CV comorbidities.

Therapeutic potentials of mesenchymal stem cells on the renal cortex of experimentally induced hypertensive albino rats: Relevant role of Nrf2

Bone marrow derived-mesenchymal stem cells (BM-MSCs) have brought great attention in regenerative medicine field, various experimental & clinical trials were held to investigate their therapeutic effects in different disorders. We designed a histological & immunohistochemical study to evaluate effectiveness of MSCs therapy in withhold of end-stage renal disease (ESRD) secondary to hypertension which has become a growing & striking public health problem. 30 adult male albino rats were utilized, 20 of them were exposed to experimental induction of hypertension, then divided equally to MSCs treated group (injected with 1×10⁶ fluorescent labeled cell i.v./rat), while the second one was left without treatment. Renal specimens were subjected to histopathological, ultrastructural and immunohistochemical examination for Nrf2 in addition to biochemical estimation of serum urea & creatinine. Our results documented that BM-derived MSCs exerts considerable reversing effect of histopathologic and ultrastructural hypertensive nephropathy. Moreover, immunohistochemical results clearly pointed to relevant role of Nrf2 pathway in MSCs related renal therapeutic effects.

Renoprotective effects of renin-angiotensin system inhibitor combined with calcium channel blocker or diuretic in hypertensive patients: A PRISMA-compliant meta-analysis

OBJECTIVES

To conduct a meta-analysis of studies comparing the renoprotective effects of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (ACEI/ARB) combined with either calcium channel blocker (CCB) or diuretic, but not both, in hypertensive patients.

DATA SOURCES

Pubmed, Embase, Medline, and Cochrane databases were searched to identify randomized controlled trials (RCTs) of blood pressure lowering treatments in patients with hypertension.

STUDY SELECTION

RCTs comparing the renoprotective effects of ACEI/ARB plus CCB with ACEI/ARB plus diuretic in hypertensive patients, with at least one of the following reported outcomes: urinary protein, estimated glomerular filtration rate/creatinine clearance (eGFR/CrCl), or serum creatinine.

RESULTS

Based on 14 RCTs with 18,125 patients, statistically significant benefits were found in ACEI/ARB plus CCB for maintaining eGFR/CrCl (standardized mean difference [SMD] = 0.36; 95% confidence interval [CI]: 0.20-0.53; P < 0.001), serum creatinine reduction (mean difference [MD] = -0.05 mg/dL; 95% CI: -0.07 to -0.03; P < 0.001). However, no statistical differences were found between the 2 therapeutic strategies in terms of urinary protein (MD = 7.48%; 95% CI: -6.13% to 21.08%; P = 0.28; I = 92%).

CONCLUSIONS

This meta-analysis concluded that ACEI/ARB plus CCB have a stronger effect on the maintenance of renal function in patients with hypertension than ACEI/ARB plus diuretic.

Pharmacologic Issues in treating hypertension in CKD

Antihypertensive drugs are prescribed to patients with CKD to slow down the rate of loss of residual kidney function; to reduce proteinuria, when present; and to protect other target organs from damage that is mediated by elevated blood pressure (BP). In most patients, a diuretic and a renin system blocking drug, such as an angiotensin-converting enzyme inhibitor, angiotensin receptor antagonist, or an aldosterone receptor antagonist are used. Often, 3 or more drugs are needed to achieve BP goals. Many drugs are eliminated through the kidney and in some cases dosage reductions are advisable to avoid adverse effects from high levels of medication. This article will review the various classes of antihypertensive drugs used in the management of high BP in patients with CKD, with an emphasis on pitfalls that arise when kidney function is impaired.

[Hypertension and the kidney]

Hypertension and proteinuria are common risk factors for cardiovascular morbidity and mortality, as well as for the progression of renal disease. Renal functional impairment represents an independent cardiovascular risk factor by itself. Strict antihypertensive therapy and measures to maximally reduce proteinuria can substantially improve the prognosis of renal patients. This review summarizes current evidence for the role of hypertension and proteinuria with regard to renal and cardiovascular outcomes and for the importance of intensive antihypertensive and anti-proteinuric measures.

The kidney and hypertension: causes and treatment

Chronic kidney disease is both a cause and a consequence of hypertension. Extracellular volume expansion is an important, if not the most important, contributing factor to hypertension seen in chronic kidney disease. Beyond volume expansion, chronic kidney disease-related hypertension is without truly defining characteristics. Consequently, the sequencing of antihypertensive medications for the patient with chronic kidney disease and hypertension becomes arbitrary. Prescription practice in such patients should be mindful of the need for multiple drug classes with at least one of them being a diuretic. Blood pressure goals in the patient with chronic kidney disease and hypertension are set at lower levels than those for patients with essential hypertension alone. It remains to be determined to what level blood pressure should be lowered in the patient with chronic kidney disease, however.

Primary hypertension and nephropathy

PURPOSE OF REVIEW

The relationship between primary hypertension (formerly called essential hypertension) and hypertension-associated chronic kidney disease is complex and poorly understood. The strong association between hypertension-associated chronic kidney disease and cardiovascular disease supports the existence of common mediators. We will review data indicating common mediating mechanisms for cardiovascular disease and chronic kidney disease in primary hypertension.

RECENT FINDINGS

Chronic kidney disease develops in primary hypertension due to local and systemic inflammatory mediators that cause endothelial injury. This injury is an important early step in the development of hypertension-associated vasculopathy that causes nephron ischemia with nephrosclerosis. Similar mechanisms mediate endothelial injury in cardiovascular disease and its progression. Subjects with primary hypertension at increased risk for chronic kidney disease are at higher risk for cardiovascular disease, the major cause of mortality in primary hypertension.

SUMMARY

Primary hypertension is a modifiable risk factor for both cardiovascular disease and chronic kidney disease. Better understanding of how primary hypertension leads to these outcomes might help in the development of pharmacologic strategies that retard and/or prevent chronic kidney disease in primary hypertension. Because of the strong association between cardiovascular disease and chronic kidney disease in primary hypertension, this improved understanding will likely lead to better therapies to hinder the development and/or progression of cardiovascular disease, in addition to its benefits in preventing hypertension-associated chronic kidney disease.