Recent advances in the management of secondary hypertension: chronic kidney disease

Glomerular pressure and tubular oxygen supply: a critical dual target for renal protection

The primary treatment goal of chronic kidney disease (CKD) is preserving renal function and preventing its progression to end-stage renal disease. Glomerular hypertension and tubular hypoxia are critical risk factors in CKD progression. However, the renal hemodynamics make it difficult to avoid both factors due to the existence of peritubular capillaries that supply oxygen to the renal tubules downstream from the glomerulus through the efferent arteriole. In the treatment strategies for balancing glomerular pressure and tubular oxygen supply, afferent and efferent arterioles of the glomerulus determine glomerular filtration rate and blood flow to the peritubular capillaries. Therefore, sodium-glucose cotransporter 2 inhibitors and angiotensin receptor-neprilysin inhibitors as well as classical renin-angiotensin system inhibitors, which can change the diameter of afferent and/or efferent arterioles, are promising options for balancing this dual target and achieving renal protection. This review focuses on the clinical importance of glomerular pressure and tubular oxygen supply and proposes an effective treatment modality for this dual target.

Fluid homeostatic action of dapagliflozin in patients with chronic kidney disease: the DAPA-BODY Trial

Sodium glucose cotransporter 2 (SGLT2) inhibitors have both glucose-lowering and diuretic effects. We recently reported that the SGLT2 inhibitor dapagliflozin exerts short-term fluid homeostatic action in patients with chronic kidney disease (CKD). However, the long-term effects of SGLT2 inhibitors on body fluid status in patients with CKD remain unclear. This was a prospective, non-randomized, open-label study that included a dapagliflozin treatment group (n = 73) and a control group (n = 24) who were followed for 6 months. Body fluid volume was measured using a bioimpedance analysis device. The extracellular water-to-total body water ratio (ECW/TBW), a predictor of renal outcomes, was used as a parameter for body fluid status (fluid retention, 0.400 ≤ ECW/TBW). Six-month treatment with dapagliflozin significantly decreased ECW/TBW compared with the control group (-0.65% ± 2.03% vs. 0.97% ± 2.49%, p = 0.0018). Furthermore, dapagliflozin decreased the ECW/TBW in patients with baseline fluid retention, but not in patients without baseline fluid retention (-1.47% ± 1.93% vs. -0.01% ± 1.88%, p = 0.0017). Vasopressin surrogate marker copeptin levels were similar between the control and dapagliflozin groups at 6 months (32.3 ± 33.4 vs. 30.6 ± 30.1 pmol/L, p = 0.8227). However, dapagliflozin significantly increased the change in copeptin levels at 1 week (39.0% ± 41.6%, p = 0.0010), suggesting a compensatory increase in vasopressin secretion to prevent hypovolemia. Renin and aldosterone levels were similar between the control and dapagliflozin groups at 6 months, while epinephrine and norepinephrine (markers of sympathetic nervous system activity) were significantly lower in the dapagliflozin group than in the control group. In conclusion, the SGLT2 inhibitor dapagliflozin ameliorated fluid retention and maintained euvolemic fluid status in patients with CKD, suggesting that SGLT2 inhibitors exert sustained fluid homeostatic actions in patients with various fluid backgrounds. Clinical trial registration: https://www.umin.ac.jp/ctr/, identifier [UMIN000048568].

Fluid homeostasis induced by sodium-glucose cotransporter 2 inhibitors: novel insight for better cardio-renal outcomes in chronic kidney disease

Hypertension in chronic kidney disease (CKD) patients is a risk factor for end-stage renal disease, cardiovascular events, and mortality. Thus, the prevention and appropriate management of hypertension in these patients are essential strategies for better cardio-renal outcomes. In this review, we show novel risk factors for hypertension with CKD, several promising prognostic markers and treatment for cardio-renal outcomes. Of note, the clinical use of sodium-glucose cotransporter 2 (SGLT2) inhibitors has recently expanded to non-diabetic patients with CKD and heart failure as well as diabetic patients. SGLT2 inhibitors have an antihypertensive effect, but are also associated with a low risk of hypotension. This unique mechanism of blood pressure regulation by SGLT2 inhibitors may partially depend on body fluid homeostasis, which is mediated by the autoregulation property between "accelerator" (diuretic action) and "brake" (increase in anti-diuretic hormone vasopressin and fluid intake). Mineralocorticoid receptor (MR) blockers are used in the treatment of essential hypertension and hyperaldosteronism. Recently, a new MR blocker, finerenone, has been launched as a treatment for CKD with type 2 diabetes. These advances in relation to hypertension in CKD may contribute to the reduction of renal and cardiovascular events.

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.

Update on Hypertension Research in 2021

In 2021, 217 excellent manuscripts were published in Hypertension Research. Editorial teams greatly appreciate the authors' contribution to hypertension research progress. Here, our editorial members have summarized twelve topics from published work and discussed current topics in depth. We hope you enjoy our special feature, "Update on Hypertension Research in 2021".

Urinary free cortisol excretion is associated with lumbar bone density in patients with adrenal Cushing's syndrome

Patients with adrenal Cushing's syndrome have a poor prognosis due to the autonomous hypersecretion of endogenous cortisol from the adrenal gland. Although several clinical examinations have been developed to manifest the autonomous hypersecretion of endogenous cortisol in this syndrome, it is unknown which parameter of cortisol overproduction is best associated with the adrenal cortisol content and bone and vascular complications of this syndrome. Therefore, the present study was undertaken to evaluate the parameter(s) associated with the adrenal cortisol content in patients with adrenal Cushing's syndrome, as well as to assess the associations between these parameters and the vascular and bone complications of this syndrome. Cardiovascular factors such as blood pressure and pulse rate, glucose metabolism, lipid metabolism, renal function, and indices of arteriosclerosis, except for diastolic blood pressure, failed to show an association with the adrenal cortisol content. Twenty-four-hour urinary free cortisol excretion (ρ = 0.893, P = 0.007) and plasma cortisol levels after the 1-mg (ρ = 0.857, P = 0.014) or 8-mg (ρ = 0.900, P = 0.037) overnight dexamethasone suppression test, but not plasma cortisol levels in the morning or late at night or indices of ¹³¹I-adosterol single-photon emission computed tomography-computed tomography, were significantly and positively associated with the adrenal cortisol content. Twenty-four-hour urinary free cortisol excretion, and not plasma cortisol levels after the 1- or 8-mg overnight dexamethasone suppression test, was significantly and negatively associated with lumbar spine bone density (lumbar spine bone mineral density, ρ = -0.786, P = 0.036; lumbar spine T score, ρ = -0.883, P = 0.009; and lumbar spine Z score, ρ = -0.883, P = 0.009). These results indicate that 24-h urinary free cortisol excretion is best associated with a decrease in bone density via increased adrenal cortisol overproduction and suggest that it could be used as a marker for osteoporosis in these patients.

The Pathogenesis of End-Stage Renal Disease from the Standpoint of the Theory of General Pathological Processes of Inflammation

Chronic kidney disease can progress to end-stage chronic renal disease (ESRD), which requires the use of replacement therapy (dialysis or kidney transplant) in life-threatening conditions. In ESRD, irreversible changes in the kidneys are associated with systemic changes of proinflammatory nature and dysfunctions of internal organs, skeletal muscles, and integumentary tissues. The common components of ESRD pathogenesis, regardless of the initial nosology, are (1) local (in the kidneys) and systemic chronic low-grade inflammation (ChLGI) as a risk factor for diabetic kidney disease and its progression to ESRD, (2) inflammation of the classical type characteristic of primary and secondary autoimmune glomerulonephritis and infectious recurrent pyelonephritis, as well as immune reactions in kidney allograft rejection, and (3) chronic systemic inflammation (ChSI), pathogenetically characterized by latent microcirculatory disorders and manifestations of paracoagulation. The development of ChSI is closely associated with programmed hemodialysis in ESRD, as well as with the systemic autoimmune process. Consideration of ESRD pathogenesis from the standpoint of the theory of general pathological processes opens up the scope not only for particular but also for universal approaches to conducting pathogenetic therapies and diagnosing and predicting systemic complications in severe nephropathies.