Hypertension in Chronic Kidney Disease: Novel Insights

Serum Elabela expression is decreased in hypertensive patients and could be associated with the progression of hypertensive renal damage

BACKGROUND

Elabela, a recently discovered hormonal peptide containing 32 amino acids, is a ligand for the apelin receptor. It can lower blood pressure and attenuate renal fibrosis. However, the clinicopathological relationship between Elabela level and renal damage caused by benign hypertension (BHT) and malignant hypertension (MHT) has not been elucidated. Therefore, we investigated the clinicopathological correlation between serum Elabela level and renal damage caused by BHT and MHT.

METHODS

The participants comprised 50 patients and 25 age-matched healthy adults. The 50 patients were separated into two groups: MHT (n = 25) and BHT groups (n = 25). We analyzed their medical histories, demographics, and clinical examinations, including physical and laboratory tests.

RESULTS

The results showed that serum Elabela level decreased gradually with a continuous increase in blood pressure from the healthy control group, BHT, to MHT. Moreover, Elabela levels negatively correlated with BMI (R =  - 0.27, P = 0.02), SBP (r =  - 0.64, P < 0.01), DBP (r =  - 0.58, P < 0.01), uric acid (r =  - 0.39, P < 0.01), bun (r =  - 0.53, P < 0.01), and Scr (r =  - 0.53 P < 0.01) but positively correlated with eGFR (r = 0.54, P < 0.01). Stepwise multivariate linear regression analysis showed that SBP was the variable most related to Elabela (t =  - 5.592, P < 0.01).

CONCLUSIONS

Serum Elabela levels decreased in patients with hypertension, especially malignant hypertension, and has the potential to be a marker of hypertension-related kidney damage.

Dapagliflozin-entresto protected kidney from renal hypertension via downregulating cell-stress signaling and upregulating SIRT1/PGC-1α/Mfn2-medicated mitochondrial homeostasis

This study tested whether combined dapagliflozin and entresto would be superior to mere one therapy on protecting the residual renal function and integrity of kidney parenchyma in hypertensive kidney disease (HKD) rat. In vitro results showed that the protein expressions of oxidative-stress/mitochondrial-damaged (NOX-1/NOX-2/oxidized-protein/cytosolic-cytochrome-C)/apoptotic (mitochondrial-Bax/cleaved caspeases 3, 9)/cell-stress (p-ERK/p-JNK/p-p38) biomarkers were significantly increased in H2O2-treated NRK-52E cells than those of controls that were reversed by dapagliflozin or entresto treatment. Adult-male SD rats (n = 50) were equally categorized into group 1 (sham-operated-control), group 2 (HKD by 5/6 nephrectomy + DOCA-salt/25 mg/kg/subcutaneous injection/twice weekly), group 3 (HKD + dapagliflozin/orally, 20 mg/kg/day for 4 weeks since day 7 after HKD induction), group 4 (HKD + entresto/orally, 100 mg/kg/day for 4 weeks since day 7 after HKD induction), and group 5 (HKD + dapagliflozin + entresto/the procedure and treatment strategy were identical to groups 2/3/4). By day 35, circulatory levels of blood-urine-nitrogen (BUN)/creatinine and urine protein/creatinine ratio were lowest in group 1, highest in group 2, and significantly lower in group 5 than in groups 3/4, but no difference between groups 3/4. Histopathological findings showed the kidney injury score/fibrotic area/cellular expressions of oxidative-stress/kidney-injury-molecule (8-OHdG+/KIM-1+) exhibited an identical trend, whereas the cellular expressions of podocyte components (synaptopodin/ZO-1/E-cadherin) exhibited an opposite pattern of BUN level among the groups. The protein expressions of oxidative stress/mitochondrial-damaged (NOX-1/NOX-2/oxidized protein/cytosolic-cytochrome-C/cyclophilin-D)/apoptotic (mitochondrial-Bax/cleaved-caspase 3)/mitochondrial-fission (PINK1/Parkin/p-DRP1)/autophagic (LC3BII/LC3BI ratio, Atg5/beclin-1)/MAPK-family (p-ERK/p-JNK/p-p38) biomarkers displayed a similar pattern, whereas the protein expression of mitochondria-biogenesis signaling (SIRT1/PGC-1α-Mfn2/complex I-V) displayed an opposite pattern of BUN among the groups. In conclusion, combined dapagliflozin-entresto therapy offered additional benefits on protecting the residual kidney function and architectural integrity in HKD rat.

Renal Glucose Release after Unilateral Renal Denervation during a Hypoglycemic Clamp in Pigs with an Altered Hypothalamic Pituitary Adrenal Axis after Late-Gestational Dexamethasone Injection

Previously, we demonstrated in pigs that renal denervation halves glucose release during hypoglycaemia and that a prenatal dexamethasone injection caused increased ACTH and cortisol concentrations as markers of a heightened hypothalamic pituitary adrenal axis (HPAA) during hypoglycaemia. In this study, we investigated the influence of an altered HPAA on renal glucose release during hypoglycaemia. Pigs whose mothers had received two late-gestational dexamethasone injections were subjected to a 75 min hyperinsulinaemic-hypoglycaemic clamp (<3 mmol/L) after unilateral surgical denervation. Para-aminohippurate (PAH) clearance, inulin, sodium excretion and arterio-venous blood glucose difference were measured every fifteen minutes. The statistical analysis was performed with a Wilcoxon signed-rank test. PAH, inulin, the calculated glomerular filtration rate and plasma flow did not change through renal denervation. Urinary sodium excretion increased significantly (p = 0.019). Side-dependent renal net glucose release (SGN) decreased by 25 ± 23% (p = 0.004). At 25 percent, the SGN decrease was only half of that observed in non-HPAA-altered animals in our prior investigation. The current findings may suggest that specimens with an elevated HPAA undergo long-term adaptations to maintain glucose homeostasis. Nonetheless, the decrease in SGN warrants further investigations and potentially caution in performing renal denervation in certain patient groups, such as diabetics at risk of hypoglycaemia.

The association of lead exposure with blood pressure and hypertension: a mediation analyses of estimated glomerular filtration rate

The link between lead and blood pressure was debatable, and whether it was mediated by renal function was unknown. The purpose was to investigate the relationship between blood lead concentrations and blood pressure and hypertension, as well as the mediating role of estimated glomerular filtration rate (eGFR) in this relationship. Participants aged 18 were recruited from the National Health and Nutrition Examination Survey (1999-2014) and provided with lead and blood pressure data. Multivariate linear and logistic regression, stratification, interaction tests, and a restricted cubic spline curve were used to assess the association of blood lead with systolic/diastolic blood pressure (SBP/DBP) and hypertension, and mediation effect analysis was used to investigate the role of eGFR in this relationship. A total of 20,073 subjects were enrolled, and among them, 9837 (49.01%) were male and 7800 (38.86%) were hypertensive patients. Multivariate linear and logistic regression analysis showed that blood lead levels were significantly associated with SBP (β = 3.14, 95%CI: 2.03, 4.25; P < 0.001), DBP (β = 3.50, 95%CI: 2.69, 4.30; P < 0.001), and hypertension (OR = 1.29, 95%CI: 1.09, 1.52; P = 0.0026). In comparison to the lowest blood lead quartile, the highest lead group was significantly associated with SBP (= 2.55, 95%CI: 1.66, 3.44; P = 0.0001), DBP (= 2.60, 95%CI: 1.95, 3.24; P = 0.0001), and hypertension (OR = 1.26, 95%CI: 1.10, 1.45; P = 0.0007). Mediation analysis showed that the proportion of blood lead mediated for SBP, DBP, and hypertension was 3.56% (95%CI: 0.42%, 7.96%; P = 0.0320), 6.21% (95%CI: 4.02%, 9.32%; P < 0.0001), and 17.39% (95%CI: 9.34%, 42.71%; P < 0.0001), respectively. Adjusted restricted cubic spline curves presented a non-linear correlation of blood lead levels with DBP (P-non-linearity < 0.001), linear with SBP (P-non-linearity = 0.203), and hypertension (P-non-linearity = 0.763). Our findings demonstrated that blood lead levels were non-linear with DBP, but linear with SBP and hypertension, and this relationship was mediated by eGFR.

Co-occurrence of chronic kidney disease and glaucoma: Epidemiology and etiological mechanisms

As the histology, physiology, and pathophysiology of eyes and kidneys show substantial overlap, it has been suggested that eye and kidney diseases, such as glaucoma and chronic kidney disease (CKD), may be closely interlinked. We review the relationship between CKD and various subtypes of glaucoma, including primary open-angle glaucoma, primary angle- closure glaucoma, normal tension glaucoma, pseudoexfoliation syndrome, and several glaucoma endophenotypes. We also discuss the underlying pathogenic mechanisms and common risk factors for CKD and glaucoma, including atherosclerosis, the renin-angiotensin system, genes and genetic polymorphisms, vitamin D deficiency, and erythropoietin. The prevalence of glaucoma appears elevated in CKD patients, and vice versa, and the literature points to many intriguing associations; however, the associations are not always confirmed, and sometimes apparently opposite observations are reported. Glaucoma and CKD are complex diseases, and their mutual influence is only partially understood.

Prognostic Factors of New-Onset Hypertension in New and Traditional Hypertension Definition in a Large Taiwanese Population Follow-up Study

The aim of this study was to determine the predictors of new-onset hypertension when the definition of hypertension is changed from the traditional definition (140/90 mmHg) to a new definition (130/80 mmHg). Using data from the Taiwan Biobank, a total of 17,072 and 21,293 participants in the new and traditional definition groups were analyzed, respectively. During a mean follow-up period of 3.9 years, 3641 and 3002 participants developed hypertension in the new and traditional definition groups, respectively. After multivariable analysis, older age (OR, 1.035; 95% CI, 1.030 to 1.039; p < 0.001), male sex (OR, 1.332; 95% CI, 1.194 to 1.486; p < 0.001), high systolic blood pressure (SBP) (OR, 1.067; 95% CI, 1.062 to 1.073; p < 0.001), high diastolic blood pressure (DBP) (OR, 1.048; 95% CI, 1.040 to 1.056; p < 0.001), high heart rate (OR, 1.007; 95% CI, 1.002 to 1.012; p = 0.004), high body mass index (BMI) (OR, 1.091; 95% CI, 1.077 to 1.106; p < 0.001), high fasting glucose (OR, 1.004; 95% CI, 1.001 to 1.006; p = 0.002), and high triglycerides (OR, 1.001; 95% CI, 1.000 to 1.001; p = 0.004) were significantly associated with new-onset hypertension in the new definition group. In the traditional definition group, the predictors of new-onset hypertension were older age (OR, 1.038; 95% CI, 1.032 to 1.043; p < 0.001), high SBP (OR, 1.078; 95% CI, 1.072 to 1.084; p < 0.001), high DBP (OR, 1.039; 95% CI, 1.031 to 1.046; p < 0.001), high heart rate (OR, 1.005; 95% CI, 1.000 to 1.010; p = 0.032), high BMI (OR, 1.072; 95% CI, 1.058 to 1.087; p < 0.001), high fasting glucose (OR, 1.003; 95% CI, 1.000 to 1.005; p = 0.020), low cholesterol (OR, 0.998; 95% CI, 0.997 to 0.999; p = 0.004), high triglycerides (OR, 1.001; 95% CI, 1.000 to 1.001; p = 0.001), and low estimated glomerular filtration rate (eGFR) (OR, 0.995; 95% CI, 0.993 to 0.997; p < 0.001). In conclusion, older age, high SBP and DBP, high heart rate, high BMI, high fasting glucose, and high triglycerides were useful predictors of new-onset hypertension in both the new and traditional definition groups. However, male sex was a significant predictor of new-onset hypertension only in the new definition group, and low cholesterol and low eGFR were significant predictors of new-onset hypertension only in the traditional definition group. Hence, changing the diagnostic cut-off value for hypertension may have a significant impact on the association of some clinical and laboratory parameters with new-onset hypertension.

Aortic stiffness and aortic-brachial stiffness mismatch as markers of renal dysfunction in hypertension

PURPOSE

The dismal combination of hypertension and chronic kidney disease potentiates both cardiovascular disease and loss of renal function. Research points to the importance of arterial and left ventricular stiffening in this process but few studies have compared aspects of central and peripheral hemodynamics in relation to renal function in hypertension.

MATERIALS AND METHODS

We investigated 107 hypertensive individuals with renal function ranging from normal to severe dysfunction with pulse wave analysis to obtain central blood pressures (BP), augmentation index, carotid-femoral and carotid-radial pulse wave velocity (cfPWV, crPWV), aortic-to-brachial stiffness mismatch (cfPWV/crPWV), endothelial function by forearm flow-mediated vasodilation and myocardial microvascular function by subendocardial viability ratio, and indices of left ventricular structure (left ventricular mass index and relative wall thickness, RWT) and diastolic function (left atrial volume index, E/A, and E/é).

RESULTS

Mean age was 58 years, BP 149/87 mm Hg, 9% had cardiovascular disease, and 31% were on antihypertensive treatment. Mean estimated glomerular filtration rate (eGFR) was 74 (range 130-21) ml/min × 1.73 m². Whereas cfPWV and cfPWV/crPWV were independently related to eGFR (r = -0.20, p = 0.002, r = -0.16, p = 0.01), central diastolic BP (r = 0.21, p = 0.04), RWT (r = -0.34, p = 0.001), E/é (r = -0.39, p < 0.001) and E/A (r = 0.27, p = 0.01) were related to eGFR in bivariate correlations, but these findings were not retained in multivariate analyses. Remaining markers of hypertensive heart disease and measures of microvascular function were not related to eGFR.

CONCLUSION

Increased aortic stiffness and aortic-to-brachial stiffness mismatch are independently related to reduced eGFR in hypertensive patients, suggesting an important role for aortic stiffness in the evolution of hypertension-mediated renal dysfunction. Aortic stiffness and aortic-brachial stiffness mismatch may be useful early markers to find hypertensive patients at risk for decline in renal function.

The Impact of Functional Bars and Adapted Physical Activity on Quality of Life in Chronic Kidney Disease: A Pilot Study

Chronic kidney disease (CKD) represents a public health problem because it is characterized by several comorbidities, including uremic sarcopenia (US), and a poor quality of life. Currently, there are no standardized treatments available to counteract the onset of US but only some possible therapeutic approaches to slow its progression. The aim of this pilot study is to collect descriptive data in order to design a clinical trial based on the power analysis and simple size. The purpose of this pilot study was to evaluate the possible beneficial action induced by the functional anti-inflammatory and antioxidant bars in combination with the adapted physical activity (APA), on the onset and progression of US and other related-CKD comorbidities. We enrolled 21 CKD patients under conservative therapy, divided into four groups: (A) the physical exercise program (PEP), three times a week, in combination with the daily consumption of the two functional bars group; (B) the PEP group; (C) the daily consumption of the two functional bars group; (D) the control group. The duration of the study protocol was 12 weeks. We observed an improvement trend of body composition, blood pressure levels, lipid metabolism, and functional test in A and B groups. These preliminary data would seem to confirm the effectiveness of APA and to demonstrate the additive role of the natural bioactive compound’s assumption in countering US and other CKD comorbidities.

Cerebrovascular Disease and Cognition in Chronic Kidney Disease Patients

Chronic kidney disease (CKD) affects both brain structure and function. Patients with CKD have a higher risk of both ischemic and hemorrhagic strokes. Age, prior disease history, hypertension, diabetes, atrial fibrillation, smoking, diet, obesity, and sedimentary lifestyle are most common risk factors. Renal-specific pathophysiologic derangements, such as oxidative stress, chronic inflammation, endothelial dysfunction, vascular calcification, anemia, gut dysbiosis, and uremic toxins are important mediators. Dialysis initiation constitutes the highest stroke risk period. CKD significantly worsens stroke outcomes. It is essential to understand the risks and benefits of established stroke therapeutics in patients with CKD, especially in those on dialysis. Subclinical cerebrovascular disease, such as of silent brain infarction, white matter lesions, cerebral microbleeds, and cerebral atrophy are more prevalent with declining renal function. This may lead to functional brain damage manifesting as cognitive impairment. Cognitive dysfunction has been linked to poor compliance with medications, and is associated with greater morbidity and mortality. Thus, understanding the interaction between renal impairment and brain is important in to minimize the risk of neurologic injury in patients with CKD. This article reviews the link between chronic kidney disease and brain abnormalities associated with CKD in detail.

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

Hypertension in chronic kidney disease (CKD) is the most commonly observed comorbidity and is a risk factor for end-stage renal disease (ESRD) as well as cardiovascular disease (CVD) and mortality. Therefore, suitable blood pressure (BP) control in CKD patients is very important in preventing both CVD and ESRD. We herein describe the recommendations of target BP and the pharmacological drug options from the evidence-based clinical practice guidelines for CKD in 2018 by the Japanese Society of Nephrology (JSN CKD 2018) and recent advances in the management of hypertension in CKD, including sodium-glucose cotransporter (SGLT) 2 inhibitors, mineralocorticoid receptor blockers, and renal denervation. In particular, SGLT2 inhibitors are a new class of "antihypertensive drugs" that have a homeostatic mechanism that regulates body fluid volume in addition to diuretic action, which may be closely associated with their cardiorenal protective properties.

Comparison of self- and nurse-measured office blood pressure in patients with chronic kidney disease

OBJECTIVE

As blood pressure (BP) control is very important in chronic kidney disease (CKD), we investigated how office BP is influenced by the measurement circumstances and compared nonautomated self- and nurse-measured BP values.

MATERIALS AND METHODS

Two hundred stage 1-5 CKD patients with scheduled visits to an outpatient clinic were randomized to either self-measured office BP (SMOBP) followed by nurse-measured office BP (NMOBP) or NMOBP followed by SMOBP. The participants had been educated to perform the self-measurement in at least one previous visit. The SMOBP and NMOBP measurement series both consisted of three recordings, and the means of the last two recordings during SMOBP and NMOBP were compared for the 174 (mean age 52.5 years) with complete BP data.

RESULTS

SMOBP and NMOBP showed similar systolic (135.3 ± 16.6 vs 136.4 ± 17.4 mmHg, Δ = 1.1 mmHg, P = 0.13) and diastolic (81.5 ± 10.2 vs 82.2 ± 10.4 mmHg, Δ = 0.6 mmHg, P = 0.09) values. The change in BP from the first to the third recording was not different for SMOBP and NMOBP. In 17 patients, systolic SMOBP was ≥10 mmHg higher than NMOBP and in 28 patients systolic NMOBP exceeded SMOBP by ≥10 mmHg. The difference between systolic SMOBP and NMOBP was independent of CKD stage and the number of medications, but significantly more pronounced in patients above 60 years.

CONCLUSION

In a population of CKD patients, there is no clinically relevant difference in SMOBP and NMOBP when recorded at the same visit. However, in 25% of the patients, systolic BP differs ≥10 mmHg between the two measurement modalities.

Secondary Hypertension: Novel Insights

It is estimated that 5-10% of hypertensive patients have secondary hypertension. The main causes of secondary hypertension are parenchymal renal disease, primary aldosteronism and renovascular hypertension. The identification of these patients is important because it enables the etiological management of the underlying disease and in some cases leads to blood pressure control without antihypertensive medications. On the other hand, diagnostic evaluation for secondary hypertension often includes complex and expensive tests and should be performed only in patients with a strong clinical suspicion for its presence. If preliminary screening tests suggest the presence of secondary hypertension, these patients should be referred to specialized centers for further diagnostic evaluation and comprehensive management.