Hypertension and kidneys: unraveling complex molecular mechanisms underlying hypertensive renal damage

The relationship between dietary inflammatory index (DII) and early renal injury in population with/without hypertension: analysis of the National health and nutrition examination survey 2001-2002

BACKGROUND

Inflammation plays a crucial role in occurrence of kidney injury, and specific dietary patterns can influence systemic inflammation levels. However, the relationship between dietary inflammatory potential and early-stage kidney damage remains unclear.

METHOD

2,108 participants was recruited from 2001-2002 National Health and Nutrition Examination Survey (NHANES). Dietary Inflammatory Index (DII) is utilized to assess dietary inflammatory potential, calculated through a 24-h dietary recall questionnaire. Early renal injury was evaluated using urinary albumin to creatinine (UACR), cystatin C (CysC), β-2 microglobulin (β2M), and estimated glomerular filtration rate (eGFR) based on serum creatinine (eGFRs), cystatin C (eGFRc), and both Scr and CysC (eGFRs&c). Participant characteristics were analyzed, and association between DII, hypertension, and early renal injury markers was explored using multiple linear and logistic regression models.

RESULTS

The average age of participants was 53.9 years. DII exhibited a positive correlation with UACR (β = -0.048[0.017,0.078]), β2M (β = 0.019[0.010,0.027]), CysC (β = 0.012 [0.004,0.021]). Conversely, a negative correlation was observed between DII and eGFRc (β = -1.126[-1.554, -0.699]), eGFRs&c (β=-1.101[-1.653, -0.549]). A significant association was observed between hypertension and abnormality of early kidney damage markers. Subgroup analysis reveals that the positive correlation between DII and the occurrence of abnormal markers of early kidney damage is only observed in individuals with hypertension. Furthermore, an interaction between DII and hypertension was detected in eGFRs&c (OR:1.250[1.042, 1.499], p for interaction = 0.03).

CONCLUSION

Higher levels of DII may be associated with occurrence of early kidney damage. For individuals with hypertension, avoiding excessive consumption of pro-inflammatory foods may reduce the risk of renal injury.

Advance on Chinese Medicine for Hypertensive Renal Damage: Focus on the Complex Molecular Mechanisms

Hypertensive renal damage (HRD) is a major cause of end-stage renal disease. Among the causes of end-stage renal disease, HRD accounts for nearly 34% of the total number of cases. Antihypertensive treatment is primarily drug-based, but therapeutic efficacy is less effective and can have serious side effects. Chinese medicine (CM) has significant advantages in the treatment of HRD. CM is rich in various active ingredients and has the property of targeting multiple targets and channels. Therefore, the regulatory network of CM on disease is complex. A large number of CM have been employed to treat HRD, either as single applications or as part of compound formulations. The key possible mechanisms of CM for HRD include regulation of the renin-angiotensin-aldosterone system, antioxidation, anti-inflammation, rescue of endothelial function, regulation of vasoactive substance secretion and obesity-related factors, etc. This review summarized and discussed the recent advance in the basic research mechanisms of CM interventions for HRD and pointed out the challenges and future prospects.

Targeting of G protein-coupled receptor 39 alleviates angiotensin II-induced renal damage by reducing ribonucleotide reductase M2

Renal fibrosis, apoptosis and autophagy are the main pathological manifestations of angiotensin II (Ang II)-induced renal injury. G protein-coupled receptor 39 (GPR39) is highly expressed in various tissues including the kidney, but its role in the kidney is entirely unclear. This study was performed to investigate the underlying mechanism by which knockdown of GPR39 alleviated Ang II-induced renal injury. In vivo, GPR39 knockout (KO) mice were constructed and infused with Ang II for 4 weeks, followed by renal function tests. In vitro, Ang II-induced cells were treated with si-GPR39 for 48 h. Fibrosis, apoptosis and autophagy were detected in both cells and mice. The underlying mechanism was sought by mRNA transcriptome sequencing and validated in vitro. GPR39 was upregulated in renal tissues of mice with Ang II-mediated renal injury. Knockdown of GPR39 ameliorated renal fibrosis, apoptosis, and autophagy, and decreased the expression of ribonucleotide reductase M2 (RRM2). In vitro, knockdown of GPR39 was also identified to improve the Ang II-induced cell fibrosis, apoptosis, and autophagy. mRNA transcriptome results showed that knockout of GPR39 reduced the expression of RRM2 in Ang II-induced kidney tissue. Activation of RRM2 could reverse the therapeutic effect of GPR39 knockout, and the inhibitor of RRM2 could improve the cell fibrosis, apoptosis and autophagy caused by GPR39 agonist. These results indicated that targeting of GPR39 could alleviate Ang II-induced renal fibrosis, apoptosis, and autophagy via reduction of RRM2 expression, and GPR39 may serve as a potential target for Ang II-induced renal injury.

Effect of preceding drug therapy on the renal and cardiovascular outcomes of combined sodium-glucose cotransporter-2 inhibitor and glucagon-like peptide-1 receptor agonist treatment in patients with type 2 diabetes and chronic kidney disease

AIM

To conduct a post hoc subgroup analysis of patients with type 2 diabetes (T2D) from the RECAP study, who were treated with sodium-glucose cotransporter-2 (SGLT2) inhibitor and glucagon-like peptide 1 receptor agonist (GLP-1RA) combination therapy, focusing only on those patients who had chronic kidney disease (CKD), to examine whether the composite renal outcome differed between those who received SGLT2 inhibitor treatment first and those who received a GLP-1RA first.

METHODS

We included 438 patients with CKD (GLP-1RA-first group, n = 223; SGLT2 inhibitor-first group, n = 215) from the 643 T2D patients in the RECAP study. The incidence of the composite renal outcome, defined as progression to macroalbuminuria and/or a ≥50% decrease in estimated glomerular filtration rate (eGFR), was analysed using a propensity score (PS)-matched model. Furthermore, we calculated the win ratio for these composite renal outcomes, which were weighted in the following order: (1) both a ≥50% decrease in eGFR and progression to macroalbuminuria; (2) a decrease in eGFR of ≥50% only; and (3) progression to macroalbuminuria only.

RESULTS

Using the PS-matched model, 132 patients from each group were paired. The incidence of renal composite outcomes did not differ between the two groups (GLP-1RA-first group, 10%; SGLT2 inhibitor-first group, 17%; odds ratio 1.80; 95% confidence interval [CI] 0.85 to 4.26; p = 0.12). The win ratio of the GLP-1RA-first group versus the SGLT2 inhibitor-first group was 1.83 (95% CI 1.71 to 1.95; p < 0.001).

CONCLUSION

Although the renal composite outcome did not differ between the two groups, the win ratio of the GLP-1RA-first group versus the SGLT2 inhibitor-first group was significant. These results suggest that, in GLP-1RA and SGLT2 inhibitor combination therapy, the addition of an SGLT2 inhibitor to baseline GLP-1RA treatment may lead to more favourable renal outcomes.

Adhesion G Protein-Coupled Receptor Gpr126 (Adgrg6) Expression Profiling in Diseased Mouse, Rat, and Human Kidneys

Uncovering the function of understudied G protein-coupled receptors (GPCRs) provides a wealth of untapped therapeutic potential. The poorly understood adhesion GPCR Gpr126 (Adgrg6) is widely expressed in developing kidneys. In adulthood, Gpr126 expression is enriched in parietal epithelial cells (PECs) and epithelial cells of the collecting duct and urothelium. Whether Gpr126 plays a role in kidney disease remains unclear. Here, we characterized Gpr126 expression in diseased kidneys in mice, rats, and humans. RT-PCR data show that Gpr126 expression is altered in kidney disease. A quantitative RNAscope® analysis utilizing cell type-specific markers revealed that Gpr126 expression upon tubular damage is mainly increased in cell types expressing Gpr126 under healthy conditions as well as in cells of the distal and proximal tubules. Upon glomerular damage, an increase was mainly detected in PECs. Notably, Gpr126 expression was upregulated in an ischemia/reperfusion model within hours, while upregulation in a glomerular damage model was only detected after weeks. An analysis of kidney microarray data from patients with lupus nephritis, IgA nephropathy, focal segmental glomerulosclerosis (FSGS), hypertension, and diabetes as well as single-cell RNA-seq data from kidneys of patients with acute kidney injury and chronic kidney disease indicates that GPR126 expression is also altered in human kidney disease. In patients with FSGS, an RNAscope® analysis showed that GPR126 mRNA is upregulated in PECs belonging to FSGS lesions and proximal tubules. Collectively, we provide detailed insights into Gpr126 expression in kidney disease, indicating that GPR126 is a potential therapeutic target.

Preliminary Exploration of Potential Active Ingredients and Molecular Mechanisms of Yanggan Yishui Granules for Treating Hypertensive Nephropathy Using UPLC-Q-TOF/MS Coupled with Network Pharmacology and Molecular Docking Strategy

Hypertensive nephropathy (HN) is a prevalent complication of hypertension and stands as the second primary reason for end-stage renal disease. Research in clinical settings has revealed that Yanggan Yishui Granule (YGYSG) has significant therapeutic effects on HN. However, the material basis and action mechanisms of YGYSG against HN remain unclear. Consequently, this study utilized a comprehensive method integrating ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS), network pharmacology, and molecular docking to delineate the active ingredients and potential therapeutic mechanisms of YGYSG for treating HN. Firstly, sixty distinct components were recognized in total as potential active ingredients in YGYSG by UPLC-Q-TOF/MS. Subsequently, the mechanisms of YGYSG against HN were revealed for the first time using network pharmacology. 23 ingredients played key roles in the complete network and were the key active ingredients, which could affect the renin-angiotensin system, fluid shear stress and atherosclerosis, HIF-1 signaling pathway, and AGE-RAGE signaling pathway in diabetic complications by regulating 29 key targets such as TNF, IL6, ALB, EGFR, ACE, and MMP2. YGYSG could treat HN through the suppression of inflammatory response and oxidative stress, attenuating the proliferation of renal vascular smooth muscle cells, lessening glomerular capillary systolic pressure, and ameliorating renal dysfunction and vascular damage through the aforementioned targets and pathways. Molecular docking results revealed that most key active ingredients exhibited a high affinity for binding to the key targets. This study pioneers in clarifying the bioactive compounds and molecular mechanisms of YGYSG against HN and offers scientific reference into the clinical application.

Association of mental health-related patient reported outcomes with blood pressure in adults and children with primary proteinuric glomerulopathies

INTRODUCTION

The prevalence of mental health disorders including anxiety and depression is increasing and is linked to hypertension in healthy individuals. However, the relationship of psychosocial patient-reported outcomes on blood pressure (BP) in primary proteinuric glomerulopathies is not well characterized. This study explored longitudinal relationships between psychosocial patient-reported outcomes and BP status among individuals with proteinuric glomerulopathies.

METHODS

An observational cohort study was performed using data from 745 adults and children enrolled in the Nephrotic Syndrome Study Network (NEPTUNE). General Estimating Equations for linear regression and binary logistic analysis for odds ratios were performed to analyze relationships between the exposures, longitudinal Patient-Reported Outcome Measurement Information System (PROMIS) measures and BP and hypertension status as outcomes.

RESULTS

In adults, more anxiety was longitudinally associated with higher systolic and hypertensive BP. In children, fatigue was longitudinally associated with increased odds of hypertensive BP regardless of the PROMIS report method. More stress, anxiety, and depression were longitudinally associated with higher systolic BP index, higher diastolic BP index, and increased odds of hypertensive BP index in children with parent-proxy patient-reported outcomes.

DISCUSSION/CONCLUSION

Chronically poor psychosocial patient-reported outcomes may be significantly associated with higher BP and hypertension in adults and children with primary proteinuric glomerulopathies. This interaction appears strong in children but should be interpreted with caution, as multiple confounders related to glomerular disease may influence both mental health and BP independently. That said, access to mental health resources may help control BP, and proper disease and BP management may improve overall mental health.

Mechanisms of inflammation modulation by different immune cells in hypertensive nephropathy

Hypertensive nephropathy (HTN) is the second leading cause of end-stage renal disease (ESRD) and a chronic inflammatory disease. Persistent hypertension leads to lesions of intrarenal arterioles and arterioles, luminal stenosis, secondary ischemic renal parenchymal damage, and glomerulosclerosis, tubular atrophy, and interstitial fibrosis. Studying the pathogenesis of hypertensive nephropathy is a prerequisite for diagnosis and treatment. The main cause of HTN is poor long-term blood pressure control, but kidney damage is often accompanied by the occurrence of immune inflammation. Some studies have found that the activation of innate immunity, inflammation and acquired immunity is closely related to the pathogenesis of HTN, which can cause damage and dysfunction of target organs. There are more articles on the mechanism of diabetic nephropathy, while there are fewer studies related to immunity in hypertensive nephropathy. This article reviews the mechanisms by which several different immune cells and inflammatory cytokines regulate blood pressure and renal damage in HTN. It mainly focuses on immune cells, cytokines, and chemokines and inhibitors. However, further comprehensive and large-scale studies are needed to determine the role of these markers and provide effective protocols for clinical intervention and treatment.

Soybean-derived antihypertensive hydrolysates attenuate Ang II-induced renal damage by modulating MAPK and NF-κB signaling pathways

Hypertension-induced kidney injury is considered a vital consequence of long-term and uncontrolled hypertension, which is commonly associated with an excessive accumulation of angiotensin II (Ang II) from hyperactivated RAS. Antihypertensive peptides have a significant effect on blood pressure regulation, but few studies have focused on the ameliorative function of antihypertensive peptides on renal injury. This study explored the effects of soybean protein-derived hydrolysate (SPH) on SHR and Ang II-induced HK-2 cells. SPH significantly attenuated blood pressure and alleviated renal pathological injury in SHRs after oral gavage administration. According to the pathological results, the kidneys of SHRs showed inflammation and SPH attenuated inflammatory cell infiltration in the kidneys of SHRs. Immunohistochemical analysis further revealed that SPH inhibited MCP-1 expression and increased Nrf2 expression in the kidneys. An in vitro HK-2 cell model demonstrated that SPH exhibited optimal activity for reducing Ang II-induced inflammatory cytokines and ROS overproduction. Mechanistically, SPH was observed to regulate MAPK/JNK and NF-κB signaling pathways. These findings indicate that potent antihypertensive SPH significantly ameliorates hypertension-induced kidney damage.

Urinary proteomics reveals biological processes related to acute kidney injury in Bothrops atrox envenomings

Acute kidney injury (AKI) is a critical systemic complication caused by Bothrops envenoming, a neglected health problem in the Brazilian Amazon. Understanding the underlying mechanisms leading to AKI is crucial for effectively mitigating the burden of this complication. This study aimed to characterize the urinary protein profile of Bothrops atrox snakebite victims who developed AKI. We analyzed three groups of samples collected on admission: healthy subjects (controls, n = 10), snakebite victims who developed AKI (AKI, n = 10), and those who did not evolve to AKI (No-AKI, n = 10). Using liquid-chromatography tandem mass spectrometry, we identified and quantified (label-free) 1190 proteins. A panel of 65 proteins was identified exclusively in the urine of snakebite victims, with 32 exclusives to the AKI condition. Proteins more abundant or exclusive in AKI's urine were associated with acute phase response, endopeptidase inhibition, complement cascade, and inflammation. Notable proteins include serotransferrin, SERPINA-1, alpha-1B-glycoprotein, and NHL repeat-containing protein 3. Furthermore, evaluating previously reported biomarkers candidates for AKI and renal injury, we found retinol-binding protein, beta-2-microglobulin, cystatin-C, and hepcidin to be significant in cases of AKI induced by Bothrops envenoming. This work sheds light on physiological disturbances caused by Bothrops envenoming, highlighting potential biological processes contributing to AKI. Such insights may aid in better understanding and managing this life-threatening complication.

Oral Administration of Fermented Milk from Co-Starter Containing Lactobacillus plantarum Y44 Shows an Ameliorating Effect on Hypertension in Spontaneously Hypertensive Rats

Fermented dairy foods such as yogurt exhibit some beneficial effects on consumers, including relieving the symptoms of hypertension. This study aims to obtain fermented dairy products from a co-starter that have a great flavor and the auxiliary function of reducing blood pressure after longtime consumption. Commercial starter cultures composed of Lactobacillus delbrueckii subsp. bulgaricus CICC 6047 and Streptococcus thermophilus CICC 6038 were combined with Lactobacillus plantarum strains Y44, Y12, and Y16, respectively, as a combined starter culture to ferment the mixed milk of skim milk and soybean milk. The fermented milk produced using the combined starter culture mixed with L. plantarum Y44 showed an angiotensin-converting-enzyme (ACE) inhibitory activity (53.56 ± 0.69%). Some peptides that regulate blood pressure were released in the fermented milk, such as AMKPWIQPK, GPVRGPFPII, LNVPGEIVE, NIPPLTQTPV, and YQEPVL. In spontaneously hypertensive rat (SHR) oral-administration experiments compared with the gavage unfermented milk group, the gavage feeding of SHRs with the fermented milk produced using the combined starter culture mixed with L. plantarum Y44 significantly reduced the blood pressure of the SHRs after long-term intragastric administration, shown with the systolic blood pressure (SBP) and diastolic blood pressure (DBP) decreasing by 23.67 ± 2.49 mmHg and 15.22 ± 2.62 mmHg, respectively. Moreover, the abundance of short-chain fatty acids (SCFA), bacterial diversity in the gut microbiota, and SCFA levels including acetic acid, propionic acid, and butyric acid in the feces of the SHRs were increased via oral administration of the fermented milk produced using the combined starter culture containing L. plantarum Y44. Furthermore, the ACE-angiotensin II (Ang II)-angiotensin type 1 (AT 1) axis was downregulated, the angiotensin-converting-enzyme 2 (ACE 2)-angiotensin(1-7) (Ang1-7)-Mas receptor axis of the SHRs was upregulated, and then the RAS signal was rebalanced. The fermented milk obtained from the combined starter culture shows the potential to be a functional food with antihypertension properties.

Collecting duct NCOR1 controls blood pressure by regulating mineralocorticoid receptor

INTRODUCTION

Nuclear receptor corepressor 1(NCOR1) is reported to play crucial roles in cardiovascular diseases, but its function in the kidney has remained obscure.

OBJECTIVE

We aim to elucidate the role of collecting duct NCOR1 in blood pressure (BP) regulation.

METHODS AND RESULTS

Collecting duct NCOR1 knockout (KO) mice manifested increased BP and aggravated vascular and renal injury in an angiotensin II (Ang II)-induced hypertensive model. KO mice also showed significantly higher BP than littermate control (LC) mice in deoxycorticosterone acetate (DOCA)-salt model. Further study showed that collecting duct NCOR1 deficiency aggravated volume and sodium retention after saline challenge. Among the sodium transporter in the collecting duct, the expression of the three epithelial sodium channel (ENaC) subunits was markedly increased in the renal medulla of KO mice. Consistently, BP in Ang II-infused KO mice decreased significantly to the similar level as those in LC mice after amiloride treatment. ChIP analysis revealed that NCOR1 deficiency increased the enrichment of mineralocorticoid receptor (MR) on the promoters of the three ENaC genes in primary inner medulla collecting duct (IMCD) cells. Co-IP results showed interaction between NCOR1 and MR, and luciferase reporter results demonstrated that NCOR1 inhibited the transcriptional activity of MR. Knockdown of MR eliminated the increased ENaC expression in primary IMCD cells isolated from KO mice. Finally, BP was significantly decreased in Ang II-infused KO mice after treatment of MR antagonist spironolactone and the difference between LC and KO mice was abolished.

CONCLUSIONS

NCOR1 interacts with MR to control ENaC activity in the collecting duct and to regulate sodium reabsorption and ultimately BP. Targeting NCOR1 might be a promising tactic to interrupt the volume and sodium retention of the collecting duct in hypertension.

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.

The protective effect of Bergamot Polyphenolic Fraction on reno-cardiac damage induced by DOCA-salt and unilateral renal artery ligation in rats

To date, the complex pathological interactions between renal and cardiovascular systems represent a real global epidemic in both developed and developing countries. In this context, renovascular hypertension (RVH) remains among the most prevalent, but also potentially reversible, risk factor for numerous reno-cardiac diseases in humans and pets. Here, we investigated the anti-inflammatory and reno-cardiac protective effects of a polyphenol-rich fraction of bergamot (BPF) in an experimental model of hypertension induced by unilateral renal artery ligation. Adult male Wistar rats underwent unilateral renal artery ligation and treatment with deoxycorticosterone acetate (DOCA) (20 mg/kg, s.c.), twice a week for a period of 4 weeks, and 1% sodium chloride (NaCl) water (n = 10). A subgroup of hypertensive rats received BPF (100 mg/kg/day for 28 consecutive days, n = 10) by gavage. Another group of animals was treated with a sub-cutaneous injection of vehicle (that served as control, n = 8). Unilateral renal artery ligation followed by treatment with DOCA and 1% NaCl water resulted in a significant increase in mean arterial blood pressure (MAP; p< 0.05. vs CTRL) which strongly increased the resistive index (RI; p<0.05 vs CTRL) of contralateral renal artery flow and kidney volume after 4 weeks (p<0.001 vs CTRL). Renal dysfunction also led to a dysfunction of cardiac tissue strain associated with overt dyssynchrony in cardiac wall motion when compared to CTRL group, as shown by the increased time-to-peak (T2P; p<0.05) and the decreased whole peak capacity (Pk; p<0.01) in displacement and strain rate (p<0.05, respectively) in longitudinal motion. Consequently, the hearts of RAL DOCA-Salt rats showed a larger time delay between the fastest and the lowest region (Maximum Opposite Wall Delay-MOWD) when compared to CTRL group (p<0.05 in displacement and p <0.01 in strain rate). Furthermore, a significant increase in the levels of the circulating pro-inflammatory cytokines and chemokines (p< 0.05 for IL-12(40), p< 0.01 for GM-CSF, KC, IL-13, and TNF- α) and in the NGAL expression of the ligated kidney (p< 0.001) was observed compared to CTRL group. Interestingly, this pathological condition is prevented by BPF treatment. In particular, BPF treatment prevents the increase of blood pressure in RAL DOCA-Salt rats (p< 0.05) and exerts a protective effect on the volume of the contralateral kidney (p <0.01). Moreover, BPF ameliorates cardiac tissue strain dysfunction by increasing Pk in displacement (p <0.01) and reducing the T2P in strain rate motion (p<0.05). These latter effects significantly improve MOWD (p <0.05) preventing the overt dyssynchrony in cardiac wall motion. Finally, the reno-cardiac protective effect of BPF was associated with a significant reduction in serum level of some pro-inflammatory cytokines and chemokines (p<0.05 for KC and IL-12(40), p<0.01 for GM-CSF, IL-13, and TNF- α) restoring physiological levels of renal neutrophil gelatinase-associated lipocalin (NGAL, p<0.05) protein of the tethered kidney. In conclusion, the present results show, for the first time, that BPF promotes an efficient renovascular protection preventing the progression of inflammation and reno-cardiac damage. Overall, these data point to a potential clinical and veterinary role of dietary supplementation with the polyphenol-rich fraction of citrus bergamot in counteracting hypertension-induced reno-cardiac syndrome.

Does Hypertension Affect the Recovery of Renal Functions after Reversal of Unilateral Ureteric Obstruction?

Research has demonstrated that hypertension can lead to an exaggeration in the renal functional and histological changes caused by ureteral obstruction. These changes were particularly observed shortly after the release of a relatively brief period of unilateral ureteral obstruction (UUO). However, the long-term impact of hypertension on the recovery of renal functions has not been investigated beyond the immediate period after UUO reversal. In order to investigate this effect, a group of spontaneously hypertensive rats (G-SHR, n = 11) and a group of normotensive Wistar Kyoto rats (G-NTR, n = 11) were subjected to a 48 h reversible left UUO. The impact of UUO was then examined 45 days after the reversal of obstruction. The glomerular filtration rate, renal blood flow, and the fractional excretion of sodium in the post-obstructed left kidney (POK) showed similarities to the non-obstructed right kidney (NOK) in both groups. However, the changes in the albumin creatinine ratio, renal injury markers, pro-apoptotic markers, and histological changes in the G-SHR were much more pronounced compared to the G-NTR. We conclude that hypertension continues to have a significant impact on various aspects of renal injury and function, even several weeks after UUO reversal.

Effects of renal denervation on kidney function in patients with chronic kidney disease: a systematic review and meta-analysis

The present study aims to evaluate the clinical outcomes following renal denervation (RDN) for hypertensive patients with chronic kidney disease (CKD). Prospective studies published between January 1, 2010 and November 15, 2022 where systematically identified for RDN outcomes on office and ambulatory blood pressure, estimated glomerular filtration rate (eGFR), creatinine and procedural characteristics from three online databases (Medline, PubMed, EMBASE). Random effects model to combine risk ratios and mean differences was used. Where possible, clinical outcomes were pooled and analyzed at 6, 12 and 24 months. Significance was set at p ≤ 0.05. 11 prospective trials, with a total of 226 patients with treatment resistant HTN receiving RDN met the inclusion criteria. Age ranged from 42.5 ± 13.8 to 66 ± 9. Main findings of this review included a reduction in systolic and diastolic office blood pressure at 6 [-19.8 (p < 0.00001)/-15.2 mm Hg (p < 0.00001)] and 12 months [-21.2 (p < 0.00001)/-9.86 mm Hg (p < 0.0005)] follow-up compared to baseline. This was also seen in systolic and diastolic 24-hour ambulatory blood pressure at 6 [-9.77 (p = 0.05)/-3.64 mm Hg (p = 0.09)] and 12 months [-13.42 (p = 0.0007)/-6.30 mm Hg (p = 0.001)] follow-up compared to baseline. The reduction in systolic and diastolic 24-hour ambulatory blood pressure was maintained to 24 months [(-16.30 (p = 0.0002)/-6.84 mm Hg (p = 0.0010)]. Analysis of kidney function through eGFR demonstrated non-significant results at 6 (+1.60 mL/min/1.73 m2, p = 0.55), 12 (+5.27 mL/min/1.73 m2, p = 0.17), and 24 months (+7.19 mL/min/1.73 m2, p = 0.36) suggesting an interruption in natural CKD progression. Similar results were seen in analysis of serum creatinine at 6 (+0.120 mg/dL, p = 0.41), 12 (+0.100 mg/dL, p = 0.70), and 24 months (+0.07 mg/dL, p = 0.88). Assessment of procedural complications deemed RDN in a CKD cohort to be safe with an overall complication rate of 4.86%. With the current advances in RDN and its utility in multiple chronic diseases beyond hypertension, the current study summarizes critical findings that further substantiate the literature regarding the potential of such an intervention to be incorporated as an effective treatment for resistant hypertension and CKD.

Factors Affecting Mortality in Elderly Hypertensive Hospitalized Patients with COVID-19: A Retrospective Study

Purpose

Corona Virus Disease 2019 (COVID-19) endangers the health and survival of the elderly. We tried to explore factors especially kidney function which affected mortality in elderly hypertensive patients with COVID-19.

Methods

We conducted a retrospective research of 748 COVID-19 elderly patients (≥65 years old) at Zhejiang Hospital. This study compared demographic data, laboratory values, comorbidities, treatments, and clinical outcomes of hypertension and non-hypertension participants, and subgroup analysis of age and frailty was conducted in the hypertension population. Survival analysis was used to determine risk factors for death in elderly patients with COVID-19.

Results

Our study revealed that the elderly hypertensive patients with COVID-19 had higher blood urea nitrogen (BUN), serum uric acid (UA), serum creatinine (Scr), lower estimated glomerular filtration rate (eGFR), higher incidence of severity, admission to intensive care unit (ICU) and death, and longer in-hospital stay than non-hypertensive patients, which also occurred in the very elderly hypertensive patients compared with younger hypertensive patients and frail hypertensive patients compared with no-frail hypertensive patients. In addition, the prevalence of acute kidney injury (AKI) was higher in the oldest old hypertensive patients and frail hypertensive patients. Multivariate survival analysis indicated that the independent risk factors for death from COVID-19 were age ≥80 years, heart failure, antiviral therapy, calcium channel blocker (CCB) therapy, mechanical ventilation, AKI, and eGFR<60 mL/min per 1.73 m2.

Conclusion

The results of the present study suggested that the elderly hypertensive patients with COVID-19 would have more serious kidney injury, more serious disease progression and higher mortality, which also occurred in very elderly and frailty subgroup. Kidney dysfunction was closely related to mortality in elderly patients with COVID-19.

High-Salt Diet Aggravates Endothelial-to-Mesenchymal Transition in Glomerular Fibrosis in Dahl Salt-Sensitive Rats

BACKGROUND

Both diabetic and hypertensive nephropathy eventually progress to glomerulosclerosis. Previous studies revealed a potential role of endothelial-to-mesenchymal transition (EndMT) in the pathophysiology of glomerulosclerosis in diabetic rats. Therefore, we hypothesized that EndMT was also involved in the development of glomerulosclerosis in salt-sensitive hypertension. We aimed to explore the effects of high-salt diet on endothelial-to-mesenchymal transition (EndMT) in glomerulosclerosis in Dahl salt-sensitive (Dahl-SS) rats.

METHODS

Eight-week-old male rats were fed high-salt (8%NaCl; DSH group) or normal salt (0.3%NaCl; DSN group) for eight weeks, with systolic blood pressure (SBP), serum creatinine, urea, 24-hour urinary protein/sodium, renal interlobar artery blood flow, and pathological examination measured. We also examined endothelial-(CD31) and fibrosis-related protein(α-SMA) expressions in glomeruli.

RESULTS

High-salt diet increased SBP (DSH vs. DSN, 205.2 ± 8.9 vs. 135.4 ± 7.9 mm Hg, P < 0.01), 24-hour urinary protein (132.55 ± 11.75 vs. 23.52 ± 5.94 mg/day, P < 0.05), urine sodium excretions (14.09 ± 1.49 vs. 0.47 ± 0.06 mmol/day, P < 0.05), and renal interlobar artery resistance. Glomerulosclerosis increased (26.1 ± 4.6 vs. 7.3 ± 1.6%, P < 0.05), glomerular CD31 expressions decreased while α-SMA expression increased in DSH group. Immunofluorescence staining showed that CD31 and α-SMA co-expressed in glomeruli of the DSH group. The degree of glomerulosclerosis negatively correlated with CD31 expressions (r = -0.823, P < 0.01) but positively correlated with α-SMA expressions (r = 0.936, P < 0.01).

CONCLUSIONS

We demonstrated that a high-salt diet led to glomerulosclerosis involving the EndMT process, which played an essential role in glomerulosclerosis in hypertensive Dahl-SS rats.

Physiological Replication of the Human Glomerulus Using a Triple Culture Microphysiological System

The function of the glomerulus depends on the complex cell-cell/matrix interactions and replication of this in vitro would aid biological understanding in both health and disease. Previous models do not fully reflect all cell types and interactions present as they overlook mesangial cells within their 3D matrix. Herein, the development of a microphysiological system that contains all resident renal cell types in an anatomically relevant manner is presented. A detailed transcriptomic analysis of the contributing biology of each cell type, as well as functionally appropriate albumin retention in the system, is demonstrated. The important role of mesangial cells is shown in promoting the health and maturity of the other cell types. Additionally, a comparison of the incremental advances that each individual cell type brings to the phenotype of the others demonstrates that glomerular cells in simple 2D culture exhibit a state more reflective of the dysfunction observed in human disease than previously recognized. This in vitro model will expand the capability to investigate glomerular biology in a more translatable manner by the inclusion of the important mesangial cell compartment.

Isoliensinine Attenuates Renal Fibrosis and Inhibits TGF-β1/Smad2/3 Signaling Pathway in Spontaneously Hypertensive Rats

Purpose

This study aimed to investigate the molecular mechanisms of isoliensinine, a kind of bibenzyl isoquinoline alkaloid which isolated from a TCM named Lotus Plumule (Nelumbo nucifera Gaertn), in treating renal interstitial fibrosis (RIF) by using RNA sequencing, KEGG analysis and in vivo experimental approaches.

Methods

Spontaneous hypertension rats (SHRs) were randomly assigned into five groups, consisting of SHR, SHR+Isoliensinine-L (2.5 mg/kg/day), SHR+Isoliensinine-M (5 mg/kg/day), SHR+Isoliensinine-H (10 mg/kg/day), and SHR+Valsartan (10 mg/kg/day) groups (n = 6 for each group). A control group of Wistar Kyoto rats (n = 6) was also included. Rats were treated intragastrically with isoliensinine, valsartan, or double-distilled water of equal volume for 10 weeks. To examine the therapeutic impact on hypertensive renal injury, fibrosis, and its underlying mechanisms, multiple techniques were employed, including hematoxylin and eosin staining, Masson trichrome staining, RNA sequencing, gene ontology (GO) function and pathway enrichment analysis and immunohistochemistry.

Results

Resultantly, the use of isoliensinine at different concentrations or valsartan showed significant improvement in renal pathological injury in SHRs. RNA sequencing and KEGG analysis uncovered 583 differentially expressed transcripts and pathways enriched in collagen formation and ECM-receptor interaction after treatment with isoliensinine. There was also a reduction in the increase of collagen and upregulation of collagen I & III, TGF-β1, p-Smad2, and p-Smad3 in the renal tissue of SHRs. Thus, isoliensinine ameliorated renal injury and collagen deposition in hypertensive rats, and inhibiting the activation of the TGF-β1/Smad2/3 pathway might be one of the underlying mechanisms.

Conclusion

This study showed that treatment with isoliensinine effectively reduced the renal injury and fibrosis in SHRs. In addition, isoliensinine inhibited the TGF-β1/Smad2/3 signaling in-vivo. These findings provided strong evidence for the therapeutic benefits of isoliensinine in combating renal injury and fibrosis.

Association between environmental chemical exposure and albumin-to-creatinine ratio is modified by hypertension status in women of reproductive age

Chemicals have been identified as a potential risk factor of renal dysfunction. However, studies that consider both multiple chemicals and non-chemical risk factors, such as hypertension, are rare. In this study, we assessed the associations between exposure to several chemicals, including major metals, phthalates, and phenolic compounds, and the albumin-to-creatinine ratio (ACR). A group of Korean adult women in reproductive age (n = 438, aged between 20 and 49 years), who had previously been studied for association of several organic chemicals, was chosen for this purpose. We constructed multivariable linear regression models for individual chemicals and weighted-quantile sum (WQS) mixtures, by hypertension status. Among the study population, approximately 8.5% of the participants exhibited micro/macro-albuminuria (ACR ≥30 mg/g), and 18.5% and 3.9% exhibited prehypertension and hypertension, respectively. Blood cadmium and lead levels showed a stronger association with ACR only among women with prehypertension or hypertension. Among organic chemicals, depending on the statistial model, benzophenone-1 (BP-1) and mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) showed a significant association regardless of hypertension status, but most associations disappeared in the (pre)hypertensive group. These findings clearly indicate that hypertension status can modify and may potentiate the association of environmental chemicals with ACR. Our observations suggest that low-level environmental pollutant exposure may have potential adverse effects on kidney function among general adult women. Considering the prevalence of prehypertension in the general population, efforts to reduce exposure to cadmium and lead are necessary among adult women to minimize the risk of adverse kidney function.

CircRNA Galntl6 sponges miR-335 to ameliorate stress-induced hypertension through upregulating Lig3 in rostral ventrolateral medulla

Rostral ventrolateral medulla (RVLM) is thought to serve as a major vasomotor center that participates in controlling the progression of stress-induced hypertension (SIH). Circular RNAs (circRNAs) perform important functions in the regulation of diverse physiological and pathological processes. However, information concerning the functions of RVLM circRNAs on SIH remains limited. RNA sequencing was performed to profile circRNA expression in RVLMs from SIH rats, which were induced by electric foot shocks and noises. The functions of circRNA Galntl6 in reducing blood pressure (BP) and its potential molecular mechanisms on SIH were investigated via various experiments, such as Western blot and intra-RVLM microinjection. A total of 12,242 circRNA transcripts were identified, among which circRNA Galntl6 was dramatically downregulated in SIH rats. The upregulation of circRNA Galntl6 in RVLM effectively decreased the BP, sympathetic outflow, and neuronal excitability in SIH rats. Mechanistically, circRNA Galntl6 directly sponged microRNA-335 (miR-335) and restrained it to reduce oxidative stress. Reintroduction of miR-335 observably reversed the circRNA Galntl6-induced attenuation of oxidative stress. Furthermore, Lig3 can be a direct target of miR-335. MiR-335 inhibition substantially increased the expression of Lig3 and suppressed oxidative stress, and these favorable effects were blocked by Lig3 knockdown. CircRNA Galntl6 is a novel factor that impedes SIH development, and the circRNA Galntl6/miR-335/Lig3 axis represents one of the possible mechanisms. These findings demonstrated circRNA Galntl6 as a possibly useful target for the prevention of SIH.

Nicotine exacerbates diabetic nephropathy through upregulation of Grem1 expression

BACKGROUND

Diabetic nephropathy (DN) is a major complication of diabetes mellitus. Clinical reports indicate that smoking is a significant risk factor for chronic kidney disease, and the tobacco epidemic exacerbates kidney damage in patients with DN. However, the underlying molecular mechanisms remain unclear.

METHOD

In the present study, we used a diabetic mouse model to investigate the molecular mechanisms for nicotine-exacerbated DN. Twelve-week-old female mice were injected with streptozotocin (STZ) to establish a hyperglycemic diabetic model. After four months, the control and hyperglycemic diabetic mice were further divided into four groups (control, nicotine, diabetic mellitus, nicotine + diabetic mellitus) by intraperitoneal injection of nicotine or PBS. After two months, urine and blood were collected for kidney injury assay, and renal tissues were harvested for further molecular assays using RNA-seq analysis, real-time PCR, Western blot, and immunohistochemistry. In vitro studies, we used siRNA to suppress Grem1 expression in human podocytes. Then we treated them with nicotine and high glucose to compare podocyte injury.

RESULT

Nicotine administration alone did not cause apparent kidney injury, but it significantly increased hyperglycemia-induced albuminuria, BUN, plasma creatinine, and the kidney tissue mRNA expression of KIM-1 and NGAL. Results from RNA-seq analysis, real-time PCR, Western blot, and immunohistochemistry analysis revealed that, compared to hyperglycemia or nicotine alone, the combination of nicotine treatment and hyperglycemia significantly increased the expression of Grem1 and worsened DN. In vitro experiments, suppression of Grem1 expression attenuated nicotine-exacerbated podocyte injury.

CONCLUSION

Grem1 plays a vital role in nicotine-exacerbated DN. Grem1 may be a potential therapeutic target for chronic smokers with DN.

Hepatotoxicity from high-dose methotrexate in primary central nervous system lymphoma

Background

High-dose methotrexate (HDMTX) is a mainstay of primary central nervous system lymphoma (PCNSL) treatment. Transient hepatotoxicity from HDMTX has been characterized in pediatric patients but not in adults. We sought to characterize hepatotoxicity in adult PCNSL patients undergoing HDMTX treatment.

Methods

Retrospective study of 65 PCNSL patients treated at the University of Virginia from 02/01/2002 to 04/01/2020 was performed. Hepatotoxicity was defined using National Cancer Institute Common Toxicity Criteria (CTC) for adverse events, fifth version. High-grade hepatotoxicity was defined as a bilirubin or aminotransferase CTC grade of 3 or 4. Relationships between clinical factors and hepatotoxicity were assessed with logistic regression.

Results

Most patients (90.8%) had a rise of at least one aminotransferase CTC grade during HDMTX treatment. 46.2% had high-grade hepatotoxicity based on aminotransferase CTC grade. No patients developed high-grade bilirubin CTC grades during chemotherapy. Liver enzyme test values decreased to low CTC grade or normal in 93.8% of patients after the conclusion of HDMTX treatment without treatment regimen changes. Prior ALT elevation (P = .0120) was a statistically significant predictor of high-grade hepatotoxicity during treatment. Prior history of hypertension was associated with increased risk of toxic serum methotrexate levels during any cycle (P = .0036).

Conclusions

Hepatotoxicity develops in the majority of HDMTX-treated PCNSL patients. Transaminase values decreased to low or normal CTC grades in almost all patients after treatment, without modification of MTX dosage. Prior ALT elevation may predict patients' increased hepatotoxicity risk, and hypertension history may be a risk factor for delayed MTX excretion.

Polygenic scores for estimated glomerular filtration rate in a population of general adults and elderly - comparative results from the KORA and AugUR study

BACKGROUND

Polygenic scores (PGSs) combining genetic variants found to be associated with creatinine-based estimated glomerular filtration rate (eGFR_crea) have been applied in various study populations with different age ranges. This has shown that PGS explain less eGFR_crea variance in the elderly. Our aim was to understand how differences in eGFR variance and the percentage explained by PGS varies between population of general adults and elderly.

RESULTS

We derived a PGS for cystatin-based eGFR (eGFR_cys) from published genome-wide association studies. We used the 634 variants known for eGFR_crea and the 204 variants identified for eGFR_cys to calculate the PGS in two comparable studies capturing a general adult and an elderly population, KORA S4 (n = 2,900; age 24-69 years) and AugUR (n = 2,272, age ≥ 70 years). To identify potential factors determining age-dependent differences on the PGS-explained variance, we evaluated the PGS variance, the eGFR variance, and the beta estimates of PGS association on eGFR. Specifically, we compared frequencies of eGFR-lowering alleles between general adult and elderly individuals and analyzed the influence of comorbidities and medication intake. The PGS for eGFR_crea explained almost twice as much (R² = 9.6%) of age-/sex adjusted eGFR variance in the general adults compared to the elderly (4.6%). This difference was less pronounced for the PGS for eGFR_cys (4.7% or 3.6%, respectively). The beta-estimate of the PGS on eGFR_crea was higher in the general adults compared to the elderly, but similar for the PGS on eGFR_cys. The eGFR variance in the elderly was reduced by accounting for comorbidities and medication intake, but this did not explain the difference in R²-values. Allele frequencies between general adult and elderly individuals showed no significant differences except for one variant near APOE (rs429358). We found no enrichment of eGFR-protective alleles in the elderly compared to general adults.

CONCLUSIONS

We concluded that the difference in explained variance by PGS was due to the higher age- and sex-adjusted eGFR variance in the elderly and, for eGFR_crea, also by a lower PGS association beta-estimate. Our results provide little evidence for survival or selection bias.

Patchouli alcohol against renal fibrosis of spontaneously hypertensive rats via Ras/Raf-1/ERK1/2 signalling pathway

OBJECTIVES

The present study was designed to obverse the protection of patchouli alcohol (PA) ameliorates hypertensive nephropathy in spontaneously hypertensive rats (SHR) and reveals potential mechanism.

METHODS

Briefly, the adult spontaneously hypertensive rats (SHR) or Wistar-Kyoto (WKY) rats (half male and half female) were intragastric gavaged or not with PA (80, 40 and 20 mg/kg) for 8 weeks. Body weight, blood pressure (BP), renal weight, renal function and renal morphology were measured. Further, western blotting and immunohistochemical analysis were used to study the underlying mechanism.

KEY FINDINGS

Compared with the WKY group, plasmatic levels of renin, angiotensin II (Ang-II), transforming growth factor beta 1(TGF-β1), plasminogen activator inhibitor-1(PAI-1), creatinine (Cr), blood urea nitrogen (BUN), renal index, mRNA levels of ERK1/2 and α-SMA were significantly increased in SHR. Histology results showed that renal tubular injury and tubulointerstitial fibrosis occurred in SHR. After administration, SBP of captopril group decreased at each week after administration, especially at 3, 5, 6 7 and 8 weeks (P < 0.05 or P < 0.01). There is no significant effect was assessed in the olive oil group. Decreased plasma Cr, Renin, Ang-II, TGF-β1, PAI-1, SCFAs and Renin, TGF-β1, PAI-1 in renal tissues were observed significantly in captopril (P <0.05 or P < 0.01). Plasma BUN, Ang-II, TGF-β1 and PAI-1 in renal tissues decreased in the olive oil group significantly (P <0.05 or P < 0.01). PA (80, 40 and 20 mg/kg) lowered BP and plasmatic levels of Renin, Ang-II, TGF-β1 and PAI-1. Treatment with PA (40, 20 mg/kg) decreased levels of Cr, BUN and suppressed of activation of pro-fibrosis cytokines including TGF-β1 in kidney. There is no ameliorative change in the olive oil group and the captopril group (P > 0.05) while PA treatment alleviated renal tubular injury and produced dramatic collagen fibre area reductions in mesangial membrane, basement membrane, and renal interstitium obviously (P < 0.05 or P < 0.01). Treatment of SHR with PA-inhibited MFB activation and downregulated mRNA of α-SMA. Treatment with PA suppressed excessive production of the extracellular matrix (ECM) via decreasing Col I, III and FN, downregulating mRNA of tissue inhibitor of TIMP-1 along with upregulating mRNA of MMP-9. The expression of Col III and MMP-9 mRNA-reduced in the captopril group (P < 0.05). In addition, the expression of ERK1/2 and pERK1/2 also reduced in the captopril group significantly (P < 0.05 or P < 0.01). Treatment with PA (20 mg/kg) downregulated proteins expression of Raf-1, ERK1/2 and pERK1/2 and mRNA expression of Ras, Raf-1 and ERK1/2.

CONCLUSIONS

Overall, PA restored normal BP, alleviated renal dysfunction and renal fibrosis, possibly by suppressing Ang II and TGF-β1-mediated Ras/Raf-1/ERK1/2 signalling pathway.

Mitochondrial ROS Accumulation Contributes to Maternal Hypertension and Impaired Remodeling of Spiral Artery but Not IUGR in a Rat PE Model Caused by Maternal Glucocorticoid Exposure

Increased maternal glucocorticoid levels have been implicated as a risk factor for preeclampsia (PE) development. We found that pregnant rats exposed to dexamethasone (DEX) showed hallmarks of PE features, impaired spiral artery (SA) remodeling, and elevated circulatory levels of sFlt1, sEng IL-1β, and TNFα. Abnormal mitochondrial morphology and mitochondrial dysfunction in placentas occurred in DEX rats. Omics showed that a large spectrum of placental signaling pathways, including oxidative phosphorylation (OXPHOS), energy metabolism, inflammation, and insulin-like growth factor (IGF) system were affected in DEX rats. MitoTEMPO, a mitochondria-targeted antioxidant, alleviated maternal hypertension and renal damage, and improved SA remodeling, uteroplacental blood flow, and the placental vasculature network. It reversed several pathways, including OXPHOS and glutathione pathways. Moreover, DEX-induced impaired functions of human extravillous trophoblasts were associated with excess ROS caused by mitochondrial dysfunction. However, scavenging excess ROS did not improve intrauterine growth retardation (IUGR), and elevated circulatory sFlt1, sEng, IL-1β, and TNFα levels in DEX rats. Our data indicate that excess mitochondrial ROS contributes to trophoblast dysfunction, impaired SA remodeling, reduced uteroplacental blood flow, and maternal hypertension in the DEX-induced PE model, while increased sFlt1 and sEng levels and IUGR might be associated with inflammation and an impaired energy metabolism and IGF system.

Renal-Protective Roles of Lipoic Acid in Kidney Disease

The kidney is a crucial organ that eliminates metabolic waste and reabsorbs nutritious elements. It also participates in the regulation of blood pressure, maintenance of electrolyte balance and blood pH homeostasis, as well as erythropoiesis and vitamin D maturation. Due to such a heavy workload, the kidney is an energy-demanding organ and is constantly exposed to endogenous and exogenous insults, leading to the development of either acute kidney injury (AKI) or chronic kidney disease (CKD). Nevertheless, there are no therapeutic managements to treat AKI or CKD effectively. Therefore, novel therapeutic approaches for fighting kidney injury are urgently needed. This review article discusses the role of α-lipoic acid (ALA) in preventing and treating kidney diseases. We focus on various animal models of kidney injury by which the underlying renoprotective mechanisms of ALA have been unraveled. The animal models covered include diabetic nephropathy, sepsis-induced kidney injury, renal ischemic injury, unilateral ureteral obstruction, and kidney injuries induced by folic acid and metals such as cisplatin, cadmium, and iron. We highlight the common mechanisms of ALA’s renal protective actions that include decreasing oxidative damage, increasing antioxidant capacities, counteracting inflammation, mitigating renal fibrosis, and attenuating nephron cell death. It is by these mechanisms that ALA achieves its biological function of alleviating kidney injury and improving kidney function. Nevertheless, we also point out that more comprehensive, preclinical, and clinical studies will be needed to make ALA a better therapeutic agent for targeting kidney disorders.

FTIR Analysis of Renal Tissue for the Assessment of Hypertensive Organ Damage and proANP31–67 Treatment

The kidneys are one of the main end organs targeted by hypertensive disease. Although the central role of the kidneys in the regulation of high blood pressure has been long recognized, the detailed mechanisms behind the pathophysiology of renal damage in hypertension remain a matter of investigation. Early renal biochemical alterations due to salt-induced hypertension in Dahl/salt-sensitive rats were monitored by Fourier-Transform Infrared (FTIR) micro-imaging. Furthermore, FTIR was used to investigate the effects of proANP31–67, a linear fragment of pro-atrial natriuretic peptide, on the renal tissue of hypertensive rats. Different hypertension-induced alterations were detected in the renal parenchyma and blood vessels by the combination of FTIR imaging and principal component analysis on specific spectral regions. Changes in amino acids and protein contents observed in renal blood vessels were independent of altered lipid, carbohydrate, and glycoprotein contents in the renal parenchyma. FTIR micro-imaging was found to be a reliable tool for monitoring the remarkable heterogeneity of kidney tissue and its hypertension-induced alterations. In addition, FTIR detected a significant reduction in these hypertension-induced alterations in the kidneys of proANP31–67-treated rats, further indicating the high sensitivity of this cutting-edge imaging modality and the beneficial effects of this novel medication on the kidneys.

Melatonin Treatment in Kidney Diseases

Melatonin is a neurohormone that is mainly secreted by the pineal gland. It coordinates the work of the superior biological clock and consequently affects many processes in the human body. Disorders of the waking and sleeping period result in nervous system imbalance and generate metabolic and endocrine derangements. The purpose of this review is to provide information regarding the potential benefits of melatonin use, particularly in kidney diseases. The impact on the cardiovascular system, diabetes, and homeostasis causes melatonin to be indirectly connected to kidney function and quality of life in people with chronic kidney disease. Moreover, there are numerous reports showing that melatonin plays a role as an antioxidant, free radical scavenger, and cytoprotective agent. This means that the supplementation of melatonin can be helpful in almost every type of kidney injury because inflammation, apoptosis, and oxidative stress occur, regardless of the mechanism. The administration of melatonin has a renoprotective effect and inhibits the progression of complications connected to renal failure. It is very important that exogenous melatonin supplementation is well tolerated and that the number of side effects caused by this type of treatment is low.

Endothelial Progenitor Cells Affect the Growth and Apoptosis of Renal Cells by Secreting Microvesicles Carrying Dysregulated miR-205 and miR-206

Background

This study investigated the mechanism of microRNA (miRNA, miR) in microvesicles (MVs) secreted by endothelial progenitor cells (EPCs) involved in renal function in vivo and in vitro injury repair of rat primary kidney cells (PRKs).

Methods

Gene Expression Omnibus analysis of potential target miRNAs in nephrotic rats. Real-time quantitative polymerase chain reaction verified the correlation of these miRNAs and screened the effective target miRNAs and their downstream putative target mRNAs. Western blot analyzes the protein levels of DEAD-box helicase 5 (DDX5) and the activation of the proapoptotic factor caspase-3/9 (cleaved). Dil-Ac-LDL staining, immunofluorescence, and a transmission electron microscope (TEM) were used to identify the successful isolation of EPCs and PRKs and the morphology of MVs. Cell Counting Kit-8 was used to detect the effect of miRNA-mRNA on the proliferation of PRKs. Standard biochemical kits were used to detect biochemical indicators in rat blood and urine. Dual-luciferase analysis of miRNA binding to mRNA was conducted. The effect of miRNA-mRNA interaction on the apoptosis level of PRKs was analyzed by flow cytometry.

Results

A total of 13 rat-derived miRNAs were potential therapeutic targets, and miR-205 and miR-206 were screened as the targets of this study. We found that the EPC-MVs alleviated the increase of blood urea nitrogen and urinary albumin excretion and the decrease in creatinine clearance caused by hypertensive nephropathy in vivo. The effect of MVs in improving renal function indicators was promoted by miR-205 and miR-206 and inhibited by knockdown of expressed miR-205 and miR-206. In vitro, angiotensin II (Ang II) promoted growth inhibition and apoptosis of PRKs, and similarly, dysregulated miR-205 and miR-206 affected the induction of Ang II. We then observed that miR-205 and miR-206 cotargeted the downstream target DDX5 and regulated its transcriptional activity and translational levels, while also reducing the activation of proapoptotic factors caspase-3/9. Overexpressed DDX5 reversed the effects of miR-205 and miR-206.

Conclusion

By upregulating the expression of miR-205 and miR-206 in MVs secreted by EPC, the transcriptional activity of DDX5 and the activation of caspase-3/9 can be inhibited, thereby promoting the growth of PRKs and protecting the injury caused by hypertensive nephropathy.

Cross-sectional study of household solid fuel use and renal function in older adults in China

BACKGROUND

Emerging evidence links outdoor air pollution and declined renal function but the relationship between household air pollution and renal function is not well understood.

METHODS

Using cross-sectional data from the multi-provincial INTERMAP-China Prospective Study, we collected blood samples and questionnaire information on stove use and socio-demographic factors. We calculated estimated glomerular filtration rate (eGFR) from serum creatinine to assess renal function. Participants with eGFR <60 mL/min per 1.73 m2 were defined as having chronic kidney disease (CKD) in this analysis. Generalized estimating equations were used to estimate the association of household fuel with renal function and prevalent CKD in models adjusting for confounders.

RESULTS

Among the 646 enrolled adults (40-79y; 56% female), one-third exclusively used clean fuel (gas and electric) cookstoves and 11% of northern China participants (n = 49 of 434) used only clean fuel heaters, whereas the rest used solid fuel. In multivariable models, use of solid fuel cookstoves was associated with 0.17 ml/min/1.73 m2 (95% CI: -0.30, 0.64) higher eGFR and 19% (0.86, 1.64) higher prevalence of CKD than exclusive clean fuel use. Greater intensity of solid fuel use was associated with 0.25 ml/min/1.73 m2 (-0.71, 0.21) lower eGFR per 5 stove-use years, though the confidence intervals included the null, while greater current intensity of indoor solid fuel use was associated with 1.02 (1.00, 1.04) higher prevalent CKD per 100 stove-use days per year. Larger associations between current solid fuel use and intensity of use with lower eGFR and prevalent CKD were observed among participants in southern China, those with hypertension or diabetes (eGFR only), and females (CKD only), through these groups had small sample sizes and some confidence intervals included the null.

CONCLUSION

We found inconsistent evidence associating household solid fuel use and renal function in this cross-sectional study of peri-urban Chinese adults.

Hypertension in Chronic Kidney Disease: An Update on Diagnosis and Management

Hypertension (HTN) and chronic kidney disease (CKD) are pathophysiologic states that are intimately related, such that long-term HTN can lead to poor kidney function, and renal function decline can lead to worsening blood pressure (BP) control. HTN in CKD is caused by an interplay of factors, including salt and water retention, with extracellular volume expansion, sympathetic nervous system overactivity, renin-angiotensin-aldosterone system activation, and endothelial dysfunction. BP variability in the CKD population is significant, however, and thus requires close monitoring for appropriate management. With accumulating evidence, the diagnosis as well as management of HTN in CKD has been evolving in the last decade. In this comprehensive review based on current evidence and recommendations, we summarize the basics of pathophysiology, BP variability, diagnosis, and management of HTN in CKD with an emphasis on special populations with CKD.

Impact of hypertension and diabetes on the onset of chronic kidney disease in a general Japanese population

Hypertension (HT) and diabetes mellitus (DM) are both major risk factors for chronic kidney disease (CKD); however, few studies have examined the impacts of the combination of HT and DM on CKD development in general populations. We aimed to explore whether HT or DM contributes more to CKD development in a Japanese community. A total of 5823 individuals without a history of CKD who underwent specific health checkups in fiscal year 2013 were monitored until the end of March 2018. Participants were categorized as having neither HT nor DM (none group), either HT or DM, and both (HT + DM). We calculated the hazard ratios (HRs) for developing CKD in each category using Cox proportional hazards models after adjusting for age, dyslipidemia, smoking, and alcohol drinking and with the none group as the reference. We also estimated the population attributable fraction (PAF) for CKD development in populations with either HT or DM or both. During a mean follow-up of 3.0 years, 759 individuals developed CKD, with HRs of 1.56 with a 95% confidence interval (CI) [1.33, 1.83], 1.22 with a 95% CI [0.86, 1.75], and 2.83 with a 95% CI [2.22, 3.63] for the HT only, DM only and HT + DM categories, respectively. Sex-specific analysis showed similar findings. The PAFs for CKD (14.1% and 17.2% for men and women, respectively) were the highest among participants with HT only. We concluded that in this Japanese community, HT contributed more than DM to CKD development; hence, managing hypertension is important to prevent CKD as well as diabetes.

Dapagliflozin protects the kidney in a non-diabetic model of cardiorenal syndrome

Cardiorenal syndrome encompasses a spectrum of disorders involving heart and kidney dysfunction, and sharing common risk factors, such as hypertension and diabetes. Clinical studies have shown that patients with and without diabetes may benefit from using sodium-glucose cotransporter 2 inhibitors to reduce the risk of heart failure and ameliorate renal endpoints. Because the underlying mechanisms remain elusive, we investigated the effects of dapagliflozin on the progression of renal damage, using a model of non-diabetic cardiorenal disease. Dahl salt-sensitive rats were fed a high-salt diet for five weeks and then randomized to dapagliflozin or vehicle for the following six weeks. After treatment with dapagliflozin, renal function resulted ameliorated as shown by decrease of albuminuria and urine albumin-to-creatinine ratio. Functional benefit was accompanied by a decreased accumulation of extracellular matrix and a reduced number of sclerotic glomeruli. Dapagliflozin significantly reduced expression of inflammatory and endothelial activation markers such as NF-κB and e-selectin. Upregulation of pro-oxidant-releasing NADPH oxidases 2 and 4 as well as downregulation of antioxidant enzymes were also counteracted by drug treatment. Our findings also evidenced the modulation of both classic and non-classic renin-angiotensin-aldosterone system (RAAS), and effects of dapagliflozin on gene expression of ion channels/transporters involved in renal homeostasis. Thus, in a non-diabetic model of cardiorenal syndrome, dapagliflozin provides renal protection by modulating inflammatory response, endothelial activation, fibrosis, oxidative stress, local RAAS and ion channels.

Aerobic exercise inhibits renal EMT by promoting irisin expression in SHR

To determine the effect of aerobic exercise in different intensities on renal injury and epithelial-mesenchymal transformation (EMT) in the kidney of spontaneously hypertensive rats (SHR) and explore possible mechanisms, we subjected SHR to different levels of 14-week aerobic treadmill training. We tested the effects of aerobic exercise on irisin level, renal function, and EMT modulators in the kidney. We also treated angiotensin II-induced HK-2 cells with irisin and tested the changes in EMT levels. The data showed low and moderate aerobic exercise improved renal function and inhibited EMT through promoting irisin expression in SHR. However, high-intensity exercise training had no effect on renal injury and EMT in SHR but did significantly activate STAT3 phosphorylation in the kidney. These results clarify the mechanisms of exercise in improving hypertension-related renal injury and suggest that irisin might be a therapeutic target for patients with kidney injury.

Glomerular proteomic profiling of kidney biopsies with hypertensive nephropathy reveals a signature of disease progression

Hypertensive nephropathy (HN) requires a kidney biopsy as diagnostic gold-standard but histological findings are unspecific and specific prognostic markers are missing. We aimed at identifying candidate prognostic markers based on glomerular protein signatures. We studied adult patients (n = 17) with eGFR >30 ml/min/1.73m² and proteinuria <3 g/d from the Norwegian Kidney Biopsy Registry, including subjects non progressing (NP, n = 9), or progressing (P, n = 8) to end-stage renal disease (ESRD) within an average follow-up of 22 years. Glomerular cross-sections from archival kidney biopsy sections were microdissected and processed for protein extraction. Proteomic analyses were performed using Q-exactive HF mass spectrometer and relative glomerular protein abundances were compared between P and NP patients. Immunohistochemistry (IHC) was used to validate selected data. Amongst 1870 quality filtered proteins, 58 were differentially expressed in P and NP patients' glomeruli, with absolute fold changes (FC) ≥1.5, p ≤ 0.05. Supervised classifier analysis (K nearest neighbor) identified a set of five proteins, including Gamma-butyrobetaine dioxygenase (BBOX1, O75936) and Cadherin 16 (CDH16, O75309), overexpressed in P, and Eosinophil peroxidase (EPX, P11678), DnaJ homolog subfamily B member 1 (DNAJB1, P25685) and Alpha-1-syntrophin (SNTA1, Q13424), overexpressed in NP glomeruli, correctly classifying 16/17 kidney biopsy samples. Geneset Enrichment Analysis (GSEA), showed that metabolic pathways were generally enriched in P, and structural cell pathways in NP. Pathway analysis identified Epithelial Adherens Junction Signaling as most affected canonical pathway. IHC analysis confirmed overexpression of BBOX1 and Cadherin 16 in glomeruli from P patients. In conclusion, glomerular proteomic profiling can be used to discriminate P from NP HN patients.

Distribution of pathological types and epidemiological characteristics based on kidney biopsy in Northwest China

BACKGROUND

The spectrum of biopsy-confirmed kidney disease varies with regions and periods. We describe the distribution of pathological types and epidemiological characteristics of kidney diseases in Northwest China due to regional differences in geographical environment, social economy, and dietary habits.

METHODS

Kidney biopsy cases from 2005 to 2020 in Xijing Hospital were retrospectively analyzed. Pathological characteristics of patients in different periods were analyzed using the t test or chi-square test. Joinpoint regression was used to analyze trends in pathological types and disease spectrum.

RESULTS

A total of 10,528 eligible patients were included. Primary glomerular disease (PGD) accounted for the majority of the cases and exhibited an obvious downward trend, whereas secondary glomerular disease (SGD) showed an obvious upward trend. Among PGD, immunoglobulin A nephropathy (IgAN) remained the most common pathological type, and the detection rate of membranous nephropathy (MN) was significantly increased. Among SGD, Henoch-Schönlein purpura nephritis (HSPN) was the most common pathological type and may present a significant characteristic of Northwest China. Diabetic nephropathy (DN) exhibited the most obvious upward trend in the whole process, whereas the fastest growth since 2012 was in hypertensive nephropathy.

CONCLUSION

The proportion of SGD increased whereas PGD declined. IgAN remained the most common PGD, and HSPN was the most common SGD. MN and DN showed the most obvious upward trend among PGD and SGD, respectively. Changes in the spectrum of kidney disease, especially the constituent ratio of SGD, pose a great challenge to public health.

Aqueous extract of Salvia miltiorrhiza Bunge reduces blood pressure through inhibiting oxidative stress, inflammation and fibrosis of adventitia in primary hypertension

Background: Hypertension is a major risk factor for cardiovascular diseases and the leading cause of mortality worldwide. Despite the availability of antihypertensive drugs, alternative treatments are needed due to the adverse events associated with their use. Previous studies have shown that SABP, a combination of aqueous active metabolites of Salvia Miltiorrhiza Bunge DSS, Sal-A, Sal-B and PAL, has a significant antihypertensive effect. However, the underlying mechanisms remain unknown. Objective: This study aimed to determine the effects of SABP on vascular inflammation, oxidative stress, and vascular remodeling in spontaneously hypertensive rats (SHRs). Additionally, the response of adventitial fibroblasts in SHRs to SABP treatment was also studied, including their proliferation, differentiation, and migration. Methods: SABP or perindopril (positive control) were administered intraperitoneally to SHRs, and systolic blood pressure was measured using a tail-cuff approach. The effects of SABP on oxidative stress, inflammation, and vascular remodeling were investigated by transmission electron microscopy, histochemical staining, and Western blot. Adventitial fibroblasts were isolated and cultured from the adventitia of thoracic aorta in SHR and WKY rats. CCK8 assay, wound healing method and immunostaining were used to observe the effect of SABP on fibroblasts proliferation, migration and transformation into myofibroblasts. Moreover, Western blot analysis was also performed to detect the proteins related to oxidative stress, inflammation and fibrosis in adventitial fibroblasts. Results: SHRs displayed higher blood pressure with significant vascular remodeling compared to WKY rats. The thoracic aorta and adventitial fibroblasts of SHRs exhibited significant oxidative stress, inflammation and fibrosis. SABP treatment repressed oxidative stress, inflammatory reaction and vascular remodeling of thoracic aorta in SHR through the ROS/TLR4/NF-κB signaling pathway, and inhibited fibrosis of thoracic aorta. Additionally, SABP inhibited the proliferation and migration of adventitial fibroblasts and their transformation to myofibroblasts in vitro through the TGFβ/Smad3 signaling pathway. Conclusion: These findings suggest that SABP have potential as an alternative treatment for hypertension by ameliorating oxidative stress, inflammation and fibrosis. Further research is needed to fully understand the mechanisms underlying the effects of SABP.

The blood pressure targets in sepsis patients with acute kidney injury: An observational cohort study of multiple ICUs

Background

The maintenance of blood pressure is pivotal in preventing sepsis with acute kidney injury (AKI). Especially in sepsis patients treated with vasopressors. The optimal the blood pressure has been controversial to maintain renal perfusion. This study aims to explore the blood pressure target in sepsis with AKI.

Methods

We retrieved patient data from the MIMIC IV and eICU databases. The Lasso regression model was used to identify the relationship between blood pressure and sepsis in patients with AKI and remove collinearity among variables. Generalized additive models were used to estimate the blood pressure range in patients with sepsis with AKI. Statistical methods such as multivariable logistic regression, propensity score analysis, inversion probability-weighting, and doubly robust model estimation were used to verify the target blood pressure for patients with sepsis and AKI.

Results

In total, 17874 patients with sepsis were included in this study. the incidence of AKI may be related to the level of mean article pressure (MAP) and diastolic blood pressure (DBP) in sepsis patients. The range of MAPs and DBPs may be 65-73 mmHg and 50-60 mmHg in AKI patients without hypertension. The range of MAPs and DBPs may be 70-80 mmHg and 54-62 mmHg in AKI patients with hypertension. The prognosis of sepsis with AKI was unaffected by MAP or DBP. Systolic blood pressure is not associated with sepsis in patients with AKI.

Conclusions

To ensure renal perfusion, AKI patients with hypertension may require a higher MAP [70-80] versus (65-73), mmHg] and DBP [(54-62) vs (50-60), mmHg] than patients without hypertension.

Superoxide dismutase as a protective factor for microalbuminuria in hypertensive patients

Oxidative stress had been linked to hypertensive renal impairment in previous investigations. Superoxide dismutase (SOD) was a clinically available oxidative stress biomarker. The association between SOD and the microalbuminuria in hypertensive patients has not been established. From January 2017 to December 2018, data on 690 patients with essential hypertension were collected retrospectively at Shandong Provincial Qianfoshan Hospital. Patients were divided into hypertension with microalbuminuria group (HM) and hypertension without microalbuminuria group (NHM). Clinical data from patients were collected and compared between the two groups. Spearman correlation analysis was used to analyze the correlation between UACR and SOD. Univariate and multivariate logistic regression analyses were used to screen for the risk factors for HM. Our research included 556 patients in the NHM group and 134 patients in the HM group. Spearman correlation analysis showed a negative correlation between SOD and UACR (P < 0.001). Multivariate logistic regression analysis showed SOD was an independent protective factor in hypertensive patients with HM. In hypertensive patients, a substantial, negative correlation between SOD and early renal damage was found, suggesting that SOD may protect renal function.

Kidney microbiota dysbiosis contributes to the development of hypertension

Gut microbiota dysbiosis promotes metabolic syndromes (e.g., hypertension); however, the patterns that drive hypertensive pathology and could be targeted for therapeutic intervention are unclear. We hypothesized that gut microbes might translocate to the kidney to trigger hypertension. We aimed to uncover their method of colonization, and thereby how to maintain blood pressure homeostasis. Using combined approaches based on fluorescence in situ hybridization (FISH) and immunofluorescence staining, electron microscopy analysis, bacterial cultures, species identification, and RNA-sequencing-based meta-transcriptomics, we first demonstrated the presence of bacteria within the kidney of spontaneously hypertensive rats (SHRs) and its normotensive counterpart, Wistar-Kyoto rats (WKYs), and patients with hypertension. Translocated renal bacteria were coated with secretory IgA (sIgA) or remained dormant in the L-form. Klebsiella pneumoniae (K.pn) was identified in the kidneys of germ-free (GF) mice following intestinal transplantation, which suggested an influx of gut bacteria into the kidneys. Renal bacterial taxa and their function are associated with hypertension. Hypertensive hosts showed increased richness in the pathobionts of their kidneys, which were partly derived from the gastrointestinal tract. We also demonstrated the indispensable role of bacterial IgA proteases in the translocation of live microbes. Furthermore, Tartary buckwheat dietary intervention reduced blood pressure and modulated the core renal flora-host ecosystem to near-normal states. Taken together, the unique patterns of viable and dormant bacteria in the kidney provide insight into the pathogenesis of non-communicable chronic diseases and cardiometabolic diseases (e.g., hypertension), and may lead to potential novel microbiota-targeted dietary therapies.

Cellular Senescence in Metabolic-Associated Kidney Disease: An Update

Cellular senescence is described as the state where the cell cycle is arrested irreversibly, which occurs in response to various forms of stress factors in cells, leading to the senescence-associated secretory phenotype (SASP). We can assess the accumulation of senescent cells in tissues or organs through biomarkers of cellular senescence such as p16INK4a, p53, p21, and SA-β-GAL. In recent decades, a large number of studies have reported the biomarkers of increased cell senescence in pathogenic tissues, demonstrating the possible connection between cell senescence and various diseases. Kidney damage often occurs in the pathophysiological process of certain metabolic diseases, resulting in metabolic-associated kidney diseases. For example, hypertension causes systemic arteriosclerosis, and the kidney can be seriously affected by abundant blood vessels, which may lead to a decreased glomerular filtration rate (GFR) and proteinuria, resulting in hypertension-related kidney diseases. The accumulation of senescent cells may also be observed in some metabolic-associated kidney diseases (such as obesity-related nephropathy, hypertension-related nephropathy, and diabetic nephropathy). In this paper, we review existing knowledge regarding the influence of cellular senescence on metabolic-associated kidney diseases, providing new ideas for future treatment.

Effect of Co-culture of mesenchymal stem cell and glomerulus endothelial cell to promote endothelialization under optimized perfusion flow rate in whole renal ECM scaffold

In recent era, many researches on implantable bio-artificial organs has been increased owing to large gap between donors and receivers. Comprehensive organ based researches on perfusion culture for cell injury using different flow rate have not been conducted at the cellular level. The present study investigated the co-culture of rat glomerulus endothelial cell (rGEC) and rat bone marrow mesenchymal stem cells (rBMSC) to develop micro vascularization in the kidney scaffolds culturing by bioreactor system. To obtain kidney scaffold, extracted rat kidneys were decellularized by 1% sodium dodecyl sulfate (SDS), 1% triton X-100, and distilled water. Expanded rGECs were injected through decellularized kidney scaffold artery and cultured using bioreactor system. Vascular endothelial cells adhered and proliferated on the renal ECM scaffold in the bioreactor system for 3, 7 and 14 days. Static, 1 ​ml/min and 2 ​ml/min flow rates (FR) were tested and among them, 1 ​ml/min flow rate was selected based on cell viability, glomerulus character, inflammation/endothelialization proteins expression level. However, the flow injury was still existed on primary cell cultured at vessel in kidney scaffold. Therefore, co-culture of rGEC ​+ ​rBMSC found suitable to possibly solve this problem and resulted increased cell proliferation and micro-vascularization in the glomerulus, reducing inflammation and cell death which induced by flow injury. The optimized perfusion rate under rGEC ​+ ​rBMSC co-culture conditions resulted in enhanced endocellularization to make ECM derived implantable renal scaffold and might be useful as a way of treatment of the acute renal failure.

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.

Resveratrol improved kidney function and structure in malignantly hypertensive rats by restoration of antioxidant capacity and nitric oxide bioavailability

BACKGROUND

The main cause of death among patients with malignant hypertension is a kidney failure. The promising field in essential and malignant hypertension therapy could be centered on the amelioration of oxidative stress using antioxidant molecules like resveratrol. Resveratrol is a potent antioxidative agent naturally occurred in many plants that possess health-promoting properties.

METHODS

In the present study, we investigated the therapeutic potential of resveratrol, a polyphenol with anti-oxidative activity, in N^G-L-Arginine Methyl Ester (L-NAME) treated spontaneously hypertensive rats (SHR) - malignantly hypertensive rats (MHR).

RESULTS

Resveratrol significantly improves oxidative damages by modulation of antioxidant enzymes and suppression of prooxidant factors in the kidney tissue of MHR. Enhanced antioxidant defense in the kidney improves renal function and ameliorates the morphological changes in this target organ. Besides, protective properties of resveratrol are followed by the restoration of the nitrogen oxide (NO) pathway. 4) Conclusion: Antioxidant therapy with resveratrol could represent promising therapeutical approach in hypertension, especially malignant, against kidney damage.

The independent and interactive effects of phthalates exposure and hypertension on the indicators of early renal injury in US adults: Evidence from NHANES 2001-2004

The association between phthalates and early renal injury is largely unknown in adults. We aim to explore the associations of phthalates and hypertension with early renal injury, and the interactive effects of phthalate and hypertension on the early renal injury. This study enrolled 3283 U.S. adults from NHANES 2001-2004. We detected nine phthalate metabolites in spot urine. We also measured the multiple indicators of early renal injury, including albumin-to-creatinine (Cr) ratio (ACR), β2-microglobulin (B2M), cystatin C (CYST), and calculated the estimated glomerular filtration rate (eGFR), including Cr-based eGFR, CYST-based eGFR, and Cr-CYST-based eGFR. Multiple linear regression and multivariable logistic regression were used to explore the associations among urinary phthalate metabolites, hypertension, and the indicators of early renal injury. The results showed that monobenzyl phthalate (MBzP), mono (3-carboxypropyl) phthalate (MCPP), and mono (2-ethylhexyl) phthalate (MEHP) were positively associated with ACR, B2M, CYST and negatively associated with three eGFR. Mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) was positively associated with ACR, with a β value of 0.099 (95% CI: 0.046, 0.152). Meanwhile, MEHP was associated with a higher risk of ACR abnormality, with an OR value of 1.258 (95% CI: 1.067, 1.482). MBzP, MCPP, and MEOHP increased the risks of ACR, B2M, CYST, and eGFR abnormality. Hypertension was positively associated with ACR, with a β value of 0.460 (95% CI: 0.360, 0.561). We also found interactive effects of monoethyl phthalate (MEP), MCPP, MBzP, monobutyl phthalate (MnBP), and hypertension on B2M, CYST, and three kinds of eGFR. Our results indicated that certain phthalate metabolites might contribute to increased risks of early renal injury. The hypertension population may be more sensitive to the early renal injury caused by phthalates exposure than the non-hypertension population.

Positive Effect of a Pea-Clam Two-Peptide Composite on Hypertension and Organ Protection in Spontaneously Hypertensive Rats

In the present study, we prepared pea peptides with high angiotensin-converting enzyme (ACE) inhibitory activity in vitro using an enzymatic hydrolysis of pea protein and compounded them with clam peptides to obtain a pea-clam double peptide. The effects of the two-peptide composite and pea peptides on hypertension and the damage-repair of corresponding organs were studied in spontaneously hypertensive rats (SHRs). We found that both pea peptides and the two-peptide composite significantly reduced the blood pressure upon a single or long-term intragastric administration, with the two-peptide composite being more effective. Mechanistically, we found that the two-peptide composite could regulate the renal renin-angiotensin system (RAS), rebalance gut microbial dysbiosis, decrease renal and myocardial fibrosis, and improve renal and cardiac function and vascular remodeling. Additionally, hippocampal lesions caused by hypertension were also eliminated after two-peptide composite administration. Our research provides a scientific basis for the use of this two-peptide composite as a safe antihypertension ingredient in functional foods.

Inhibition of MyD88 attenuates angiotensin II-induced hypertensive kidney disease via regulating renal inflammation

BACKGROUND

Kidney damage is a frequent event in the course of hypertension. Recent researches highlighted a critical role of non-hemodynamic activities of angiotensin II (Ang II) in hypertension-associated kidney fibrosis and inflammation. These activities are mediated through toll-like receptors (TLRs) but the mechanisms by which Ang II links TLRs to downstream inflammatory and fibrogenic responses is not fully known. In this study, we investigated the role of TLR adapter protein called myeloid differentiation primary-response protein-88 (MyD88) as the potential link.

METHODS

C57BL/6 mice were administered Ang II by micro-osmotic pump infusion for 4 weeks to develop nephropathy. Mice were treated with small-molecule MyD88 inhibitor LM8. In vitro, MyD88 was blocked using siRNA or LM8 in Ang II-challenged renal tubular epithelial cells.

RESULTS

We show that MyD88 is mainly located in tubular epithelial cells and Ang II increases the interaction between TLR4 and MyD88. This interaction activates MAPKs and nuclear factor-κB (NF-κB), leading to increased production of inflammatory and fibrogenic factors. Inhibition of MyD88 by siRNA or selective inhibitor LM8 supresses MyD88-TLR4 interaction, NF-κB activation, and elaboration of inflammatory cytokines and fibrosis-associated factors. These protective actions resulted in decreased renal pathological changes and preserved renal function in LM8-treated hypertensive mice, without affecting hypertension.

CONCLUSION

These results demonstrate that Ang II induces inflammation and fibrosis in renal tubular epithelial cells through MyD88 and present MyD88 as a potential point of intervention for hypertension-associated kidney disease.