Renin-angiotensin system, hypertension, and chronic kidney disease: pharmacogenetic implications

The Contribution of the Renin-Angiotensin System to Alzheimer's Disease

The renin-angiotensin system (RAS) is becoming increasingly recognised as a biochemical pathway relevant to the development and progression of Alzheimer's disease (AD). RAS involvement in AD was initially linked to AD via numerous genetic association studies and more recent Genome-Wide Association Studies (GWAS), and in some cases in relation to classical hallmarks of AD pathology. Since these initial findings, which will be summarised here, several complementary areas of research are converging in support of what has been proposed as the Angiotensin Hypothesis for Alzheimer's disease. This hypothesis proposes how the RAS and disease-associated changes to the normal balance between opposing regulatory pathways within RAS warrant careful consideration in the pathogenesis of AD and its pathology. We discuss some of these in relation to RAS-targeting therapeutics, originally developed for the treatment of cardiovascular conditions, and how they might be repurposed as interventions for AD.

Sociocultural perceptions of physical activity and dietary habits for hypertension control: voices from adults in a rural sub-district of South Africa

BACKGROUND

Over half of adults from rural South Africa are hypertensive. Apart from pharmaceutical treatment, lifestyle changes such as increasing physical activity and reducing dietary salt have been strongly advocated for the control of hypertension. However, the control rates of hypertension for adults in rural South Africa are low. In this paper we explore whether this is due to the recommended lifestyle intervention not aligning with the individual's socio-cultural determinants of behaviour change.

AIM

To explore the social and cultural beliefs, perceptions and practices regarding physical activity and diet as a hypertension control intervention on hypertensive adults living in a rural sub-district in South Africa.

METHODS

Nine focus group discussions were conducted with hypertensive adults aged 40 years and above from Bushbuckridge sub-district in Mpumalanga Province of South Africa using a semi-structured interview guide. Each session began with introductions of the discussion theme followed by a short discussion on what the participants know about hypertension and the normal blood pressure readings. Physical activity and dietary habits were then introduced as the main subject of discussion. Probing questions were used to get more insight on a specific topic. A thematic analysis approach was used to generate codes, categories, and themes. A manual approach to data analysis was chosen and data obtained through transcripts were analysed inductively.

FINDINGS

Participants had a lack of knowledge about blood pressure normal values. Perceived causes of hypertension were alluded to psychosocial factors such as family and emotional-related issues. Physical activity practices were influenced by family and community members' attitudes and gender roles. Factors which influenced dietary practices mainly involved affordability and availability of food. To control their hypertension, participants recommend eating certain foods, emotional control, taking medication, exercising, praying, correct food preparation, and performing house chores.

CONCLUSION

Lifestyle interventions to control hypertension for adults in a rural South African setting using physical activity promotion and dietary control must consider the beliefs related to hypertension control of this population.

Nephrectomy and high-salt diet inducing pulmonary hypertension and kidney damage by increasing Ang II concentration in rats

BACKGROUND

Chronic kidney disease (CKD) is a significant risk factor for pulmonary hypertension (PH), a complication that adversely affects patient prognosis. However, the mechanisms underlying this association remain poorly understood. A major obstacle to progress in this field is the lack of a reliable animal model replicating CKD-PH.

METHODS

This study aimed to establish a stable rat model of CKD-PH. We employed a combined approach, inducing CKD through a 5/6 nephrectomy and concurrently exposing the rats to a high-salt diet. The model's hemodynamics were evaluated dynamically, alongside a comprehensive assessment of pathological changes in multiple organs. Lung tissues and serum samples were collected from the CKD-PH rats to analyze the expression of angiotensin-converting enzyme 2 (ACE2), evaluate the activity of key vascular components within the renin-angiotensin-aldosterone system (RAAS), and characterize alterations in the serum metabolic profile.

RESULTS

At 14 weeks post-surgery, the CKD-PH rats displayed significant changes in hemodynamic parameters indicative of pulmonary arterial hypertension. Additionally, right ventricular hypertrophy was observed. Notably, no evidence of pulmonary vascular remodeling was found. Further analysis revealed RAAS dysregulation and downregulated ACE2 expression within the pulmonary vascular endothelium of CKD-PH rats. Moreover, the serum metabolic profile of these animals differed markedly from the sham surgery group.

CONCLUSIONS

Our findings suggest that the development of pulmonary arterial hypertension in CKD-PH rats is likely a consequence of a combined effect: RAAS dysregulation, decreased ACE2 expression in pulmonary vascular endothelial cells, and metabolic disturbances.

Association between tomato consumption and blood pressure in an older population at high cardiovascular risk: observational analysis of PREDIMED trial

AIMS

Clinical studies have produced conflicting evidence on the effects of the consumption of tomatoes on blood pressure, and there are limited data from epidemiologic studies. This study assesses whether tomato consumption (Solanum lycopersicum L.) is associated with systolic and diastolic blood pressure, and the risk of hypertension in a prospective 3-year longitudinal study in older adults at high cardiovascular risk.

METHODS AND RESULTS

The present study was carried out within the PREDIMED (Prevención con Dieta Mediterránea) trial involving 7056 (82.5% hypertensive) participants. The consumption of tomato (g/day) was measured using a validated Food Frequency Questionnaire and categorized into four groups: lowest (<44 g), intermediate (44-82 g), upper-intermediate (82-110 g), and highest (>110 g). Multilevel linear mixed models examined blood pressure and tomato consumption association. Cox proportional-hazards models analysed hypertension risk in 1097 non-hypertensive participants, studying risk reductions vs. the lowest tomato consumers. An inverse association between tomato consumption and diastolic blood pressure was observed between the intermediate group β = -0.65 mmHg [95% confidence interval (CI): -1.20, -0.10] and the lowest consumption group. A significant inverse association was observed for blood pressure in grade 1 hypertension participants in the intermediate tomato consumption group. The risk of hypertension decreased with consumption of >110 g/day tomato (highest vs. lowest consumption; hazard ratio, 0.64 [95% CI, 0.51-0.89]).

CONCLUSION

Tomato consumption, including tomato-based products, is beneficial in preventing and managing hypertension. Higher tomato intake reduces hypertension risk by 36%, and moderate consumption lowers blood pressure, especially in grade 1 hypertension.

The role of innate immunity in diabetic nephropathy and their therapeutic consequences

Diabetic nephropathy (DN) is an enduring condition that leads to inflammation and affects a substantial number of individuals with diabetes worldwide. A gradual reduction in glomerular filtration and emergence of proteins in the urine are typical aspects of DN, ultimately resulting in renal failure. Mounting evidence suggests that immunological and inflammatory factors are crucial for the development of DN. Therefore, the activation of innate immunity by resident renal and immune cells is critical for initiating and perpetuating inflammation. Toll-like receptors (TLRs) are an important group of receptors that identify patterns and activate immune responses and inflammation. Meanwhile, inflammatory responses in the liver, pancreatic islets, and kidneys involve inflammasomes and chemokines that generate pro-inflammatory cytokines. Moreover, the activation of the complement cascade can be triggered by glycated proteins. This review highlights recent findings elucidating how the innate immune system contributes to tissue fibrosis and organ dysfunction, ultimately leading to renal failure. This review also discusses innovative approaches that can be utilized to modulate the innate immune responses in DN for therapeutic purposes.

Hyperoside mediates protection from diabetes kidney disease by regulating ROS-ERK signaling pathway and pyroptosis

Renal tubular injury is a key factor in the progression of diabetic kidney disease to end-stage renal disease. Hyperoside, a natural flavonol glycoside in various plants, is a potentially effective drug for the clinical treatment of diabetic kidney disease. However, the specific mechanisms remain unknown. Therefore, this study will explore the effect and mechanism of hyperoside on renal tubulointerstitium in diabetic kidney disease. db/db mouse (C57BL/KsJ) is a model of type 2 diabetes resulting from Leptin receptor point mutations, with the appearance of diabetic kidney disease. Therefore, db/db mice were used for in vivo experimental studies. In vitro, human renal tubular epithelial cells were incubated with bovine serum albumin to simulate the injury of renal tubular epithelial cells caused by excessive albumin in primary urine. The experimental results showed that hyperoside could improve kidney function and reduce kidney tissue damage in mice, and could inhibit oxidative stress, extracellularly regulated protein kinases 1/2 signaling activation, and pyroptosis in human renal tubular epithelial cells. Therefore, hyperoside inhibited oxidative stress by regulating the activation of the extracellularly regulated protein kinases 1/2/mitogen-activated protein kinase signaling pathway, thereby alleviating proteinuria-induced pyroptosis in renal tubular epithelial cells. This study provides novel evidence that could facilitate the clinical application of hyperoside in diabetic kidney disease treatment.

Bioactive molecules from terrestrial and seafood resources in hypertension treatment: focus on molecular mechanisms and targeted therapies

Hypertension (HTN), a complex cardiovascular disease (CVD), significantly impacts global health, prompting a growing interest in complementary and alternative therapeutic approaches. This review article seeks to provide an up-to-date and thorough summary of modern therapeutic techniques for treating HTN, with an emphasis on the molecular mechanisms of action found in substances found in plants, herbs, and seafood. Bioactive molecules have been a significant source of novel therapeutics and are crucial in developing and testing new HTN remedies. Recent advances in science have made it possible to understand the complex molecular mechanisms underlying blood pressure (BP)-regulating effects of these natural substances better. Polyphenols, flavonoids, alkaloids, and peptides are examples of bioactive compounds that have demonstrated promise in influencing several pathways involved in regulating vascular tone, reducing oxidative stress (OS), reducing inflammation, and improving endothelial function. The article explains the vasodilatory, diuretic, and renin-angiotensin-aldosterone system (RAAS) modifying properties of vital plants such as garlic and olive leaf. Phytochemicals from plants are the primary in traditional drug development as models for novel antihypertensive drugs, providing diverse strategies to combat HTN due to their biological actions. The review also discusses the functions of calcium channel blockers originating from natural sources, angiotensin-converting enzyme (ACE) inhibitors, and nitric oxide (NO) donors. Including seafood components in this study demonstrates the increased interest in using bioactive chemicals originating from marine sources to treat HTN. Omega-3 fatty acids, peptides, and minerals obtained from seafood sources have anti-inflammatory, vasodilatory, and antioxidant properties that improve vascular health and control BP. Overall, we discussed the multiple functions of bioactive molecules and seafood components in the treatment of HTN.

Risk factors for heart, cerebrovascular, and kidney diseases: evaluation of potential side effects of medications to control hypertension, hyperglycemia, and hypercholesterolemia

Background

Heart disease (HD), cerebrovascular disease (CBD), and kidney disease (KD) are serious diseases worldwide. These diseases constitute the leading causes of death worldwide and are costly to treat. An analysis of risk factors is necessary to prevent these diseases.

Data and Methods

Risk factors were analyzed using data from 2,837,334, 2,864,874, and 2,870,262 medical checkups obtained from the JMDC Claims Database. The side effects of medications used to control hypertension (antihypertensive medications), hyperglycemia (antihyperglycemic medications), and hypercholesterolemia (cholesterol medications), including their interactions, were also evaluated. Logit models were used to calculate the odds ratios and confidence intervals. The sample period was from January 2005 to September 2019.

Results

Age and history of diseases were found to be very important factors, and the risk of having diseases could be almost doubled. Urine protein levels and recent large weight changes were also important factors for all three diseases and made the risks 10%-30% higher, except for KD. For KD, the risk was more than double for individuals with high urine protein levels. Negative side effects were observed with antihypertensive, antihyperglycemic, and cholesterol medications. In particular, when antihypertensive medications were used, the risks were almost doubled for HD and CBD. The risk would be triple for KD when individuals were taking antihypertensive medications. If they did not take antihypertensive medications and took other medications, these values were lower (20%-40% for HD, 50%-70% for CBD, and 60%-90% for KD). The interactions between the different types of medications were not very large. When antihypertensive and cholesterol medications were used simultaneously, the risk increased significantly in cases of HD and KD.

Conclusion

It is very important for individuals with risk factors to improve their physical condition for the prevention of these diseases. Taking antihypertensive, antihyperglycemic, and cholesterol medications, especially antihypertensive medications, may be serious risk factors. Special care and additional studies are necessary to prescribe these medications, particularly antihypertensive medications.

Limitations

No experimental interventions were performed. As the dataset was comprised of the results of health checkups of workers in Japan, individuals aged 76 and above were not included. Since the dataset only contained information obtained in Japan and the Japanese are ethnically homogeneous, potential ethnic effects on the diseases were not evaluated.

Mouse models of preeclampsia with preexisting comorbidities

Preeclampsia is a pregnancy-specific condition and a leading cause of maternal and fetal morbidity and mortality. It is thought to occur due to abnormal placental development or dysfunction, because the only known cure is delivery of the placenta. Several clinical risk factors are associated with an increased incidence of preeclampsia including chronic hypertension, diabetes, autoimmune conditions, kidney disease, and obesity. How these comorbidities intersect with preeclamptic etiology, however, is not well understood. This may be due to the limited number of animal models as well as the paucity of studies investigating the impact of these comorbidities. This review examines the current mouse models of chronic hypertension, pregestational diabetes, and obesity that subsequently develop preeclampsia-like symptoms and discusses how closely these models recapitulate the human condition. Finally, we propose an avenue to expand the development of mouse models of preeclampsia superimposed on chronic comorbidities to provide a strong foundation needed for preclinical testing.

Renin-angiotensin-aldosterone pathway modulators in chronic kidney disease: A comparative review

Chronic kidney disease presents a health challenge that has a complex underlying pathophysiology, both acquired and inherited. The pharmacotherapeutic treatment options available today lower the progression of the disease and improve the quality of life but cannot completely cure it. This poses a challenge to the healthcare provider to choose, from the available options, the best way to manage the disease as per the presentation of the patient. As of now, the recommended first line of treatment to control the blood pressure in chronic kidney disease is the administration of renin-angiotensin-aldosterone system modulators. These are represented mainly by the direct renin inhibitor, angiotensin-converting enzyme inhibitors, and angiotensin II receptor blockers. These modulators are varied in their structure and mechanisms of action, hence showing varying treatment outcomes. The choice of administration of these modulators is determined by the presentation and the co-morbidities of the patient, the availability and affordability of the treatment option, and the expertise of the healthcare provider. A direct head-to-head comparison between these significant renin-angiotensin-aldosterone system modulators is lacking, which can benefit healthcare providers and researchers. In this review, a comparison has been drawn between the direct renin inhibitor (aliskiren), angiotensin-converting enzyme inhibitors, and angiotensin II receptor blockers. This can be of significance for healthcare providers and researchers to find the particular loci of interest, either in structure or mechanism, and to intervene as per the case presentation to obtain the best possible treatment option.

Determinants of renin cell differentiation: a single cell epi-transcriptomics approach

Rationale

Renin cells are essential for survival. They control the morphogenesis of the kidney arterioles, and the composition and volume of our extracellular fluid, arterial blood pressure, tissue perfusion, and oxygen delivery. It is known that renin cells and associated arteriolar cells descend from FoxD1 + progenitor cells, yet renin cells remain challenging to study due in no small part to their rarity within the kidney. As such, the molecular mechanisms underlying the differentiation and maintenance of these cells remain insufficiently understood.

Objective

We sought to comprehensively evaluate the chromatin states and transcription factors (TFs) that drive the differentiation of FoxD1 + progenitor cells into those that compose the kidney vasculature with a focus on renin cells.

Methods and Results

We isolated single nuclei of FoxD1 + progenitor cells and their descendants from FoxD1 ^cre/+ ; R26R-mTmG mice at embryonic day 12 (E12) (n _cells =1234), embryonic day 18 (E18) (n _cells =3696), postnatal day 5 (P5) (n _cells =1986), and postnatal day 30 (P30) (n _cells =1196). Using integrated scRNA-seq and scATAC-seq we established the developmental trajectory that leads to the mosaic of cells that compose the kidney arterioles, and specifically identified the factors that determine the elusive, myo-endocrine adult renin-secreting juxtaglomerular (JG) cell. We confirm the role of Nfix in JG cell development and renin expression, and identified the myocyte enhancer factor-2 (MEF2) family of TFs as putative drivers of JG cell differentiation.

Conclusions

We provide the first developmental trajectory of renin cell differentiation as they become JG cells in a single-cell atlas of kidney vascular open chromatin and highlighted novel factors important for their stage-specific differentiation. This improved understanding of the regulatory landscape of renin expressing JG cells is necessary to better learn the control and function of this rare cell population as overactivation or aberrant activity of the RAS is a key factor in cardiovascular and kidney pathologies.

Human Coronavirus Cell Receptors Provide Challenging Therapeutic Targets

Coronaviruses interact with protein or carbohydrate receptors through their spike proteins to infect cells. Even if the known protein receptors for these viruses have no evolutionary relationships, they do share ontological commonalities that the virus might leverage to exacerbate the pathophysiology. ANPEP/CD13, DPP IV/CD26, and ACE2 are the three protein receptors that are known to be exploited by several human coronaviruses. These receptors are moonlighting enzymes involved in several physiological processes such as digestion, metabolism, and blood pressure regulation; moreover, the three proteins are expressed in kidney, intestine, endothelium, and other tissues/cell types. Here, we spot the commonalities between the three enzymes, the physiological functions of the enzymes are outlined, and how blocking either enzyme results in systemic deregulations and multi-organ failures via viral infection or therapeutic interventions is addressed. It can be difficult to pinpoint any coronavirus as the target when creating a medication to fight them, due to the multiple processes that receptors are linked to and their extensive expression.

Acrolein plays a culprit role in the pathogenesis of diabetic nephropathy in vitro and in vivo

OBJECTIVE

Diabetic nephropathy (DN), also known as diabetic kidney disease (DKD), is a major chronic complication of diabetes and is the most frequent cause of kidney failure globally. A better understanding of the pathophysiology of DN would lead to the development of novel therapeutic options. Acrolein, an α,β-unsaturated aldehyde, is a common dietary and environmental pollutant.

DESIGN

The role of acrolein and the potential protective action of acrolein scavengers in DN were investigated using high-fat diet/ streptozotocin-induced DN mice and in vitro DN cellular models.

METHODS

Acrolein-protein conjugates (Acr-PCs) in kidney tissues were examined using immunohistochemistry. Renin-angiotensin system (RAS) and downstream signaling pathways were analyzed using quantitative RT-PCR and Western blot analyses. Acr-PCs in DN patients were analyzed using an established Acr-PC ELISA system.

RESULTS

We found an increase in Acr-PCs in kidney cells using in vivo and in vitro DN models. Hyperglycemia activated the RAS and downstream MAPK pathways, increasing inflammatory cytokines and cellular apoptosis in two human kidney cell lines (HK2 and HEK293). A similar effect was induced by acrolein. Furthermore, acrolein scavengers such as N-acetylcysteine, hydralazine, and carnosine could ameliorate diabetes-induced kidney injury. Clinically, we also found increased Acr-PCs in serum samples or kidney tissues of DKD patients compared to normal volunteers, and the Acr-PCs were negatively correlated with kidney function.

CONCLUSIONS

These results together suggest that acrolein plays a role in the pathogenesis of DN and could be a diagnostic marker and effective therapeutic target to ameliorate the development of DN.

Exploration of ACE-Inhibiting Peptides Encrypted in Artemisia annua Using In Silico Approach

The renin-angiotensin system (RAS) is involved in body fluid regulation, but one of its enzymes, angiotensin-converting enzyme (ACE), indirectly causes hypertension by constricting blood vessels. Autoimmune illness is linked to the increased risk of hypertension and cardiovascular disease. In this study, ACE-inhibiting peptides were studied from Artemisia annua proteins. In silico hydrolysis of proteins was performed by BIOPEP-UWM using proteolytic enzymes from plant, microbial, and digestive sources. The physicochemical properties of 1160 peptides were determined using the peptide package of R studio. Di- and tripeptides were mostly released with a molecular weight of 170 to 350 Da. PeptideRanker was used to select 16 peptides from a pool of 1160 peptides based on their likelihood of being bioactive. Molecular docking was performed by DS 2020 and AutoDock Vina, which revealed that the stability of the ligand-receptor complex is due to hydrogen bonding and electrostatic and hydrophobic interactions. Their binding energies ranged from -31.81 to -20.09 kJ/mol. For drug-likeness evaluation, an online tool SwissADME was used that follows the ADME rule (absorption, distribution, metabolism, and excretion) to check the pharmacokinetics and drug-likeness of the compound. In the future, the released peptides can be used to make functional nutraceutical foods against hypertension.

Lycopene: A Natural Arsenal in the War against Oxidative Stress and Cardiovascular Diseases

Lycopene is a bioactive red pigment found in plants, especially in red fruits and vegetables, including tomato, pink guava, papaya, pink grapefruit, and watermelon. Several research reports have advocated its positive impact on human health and physiology. For humans, lycopene is an essential substance obtained from dietary sources to fulfil the body requirements. The production of reactive oxygen species (ROS) causing oxidative stress and downstream complications include one of the major health concerns worldwide. In recent years, oxidative stress and its counter strategies have attracted biomedical research in order to manage the emerging health issues. Lycopene has been reported to directly interact with ROS, which can help to prevent chronic diseases, including diabetes and neurodegenerative and cardiovascular diseases. In this context, the present review article was written to provide an accumulative account of protective and ameliorative effects of lycopene on coronary artery disease (CAD) and hypertension, which are the leading causes of death worldwide. Lycopene is a potent antioxidant that fights ROS and, subsequently, complications. It reduces blood pressure via inhibiting the angiotensin-converting enzyme and regulating nitrous oxide bioavailability. It plays an important role in lowering of LDL (low-density lipoproteins) and improving HDL (high-density lipoproteins) levels to minimize atherosclerosis, which protects the onset of coronary artery disease and hypertension. Various studies have advocated that lycopene exhibited a combating competence in the treatment of these diseases. Owing to all the antioxidant, anti-diabetic, and anti-hypertensive properties, lycopene provides a potential nutraceutical with a protective and curing ability against coronary artery disease and hypertension.

Potential therapeutic efficacy of pachymic acid in chronic kidney disease induced in rats: role of Wnt/β-catenin/renin-angiotensin axis

OBJECTIVES

Chronic kidney disease (CKD) is a major public health problem associated with high mortality. The therapeutic effects of pachymic in CKD management and its underlying mechanisms have not been studied. Therefore, we aimed to investigate the possible inhibitory effect of PA on renal Wnt/β-catenin signalling in CKD.

METHODS

CKD was induced in rats by doxorubicin (DOX; 3.5 mg/kg i.p., twice weekly for 3 weeks). Rats were treated orally with PA (10 mg/kg/day), LOS (10 mg/kg/day) or their combination (PA + LOS) for 4 weeks starting after the last dose of DOX.

KEY FINDINGS

DOX-induced renal injury was characterized by high serum cystatin-C, and urine albumin/creatinine ratio, renal content of podocin and klotho were decreased. Tumour necrosis factor-α, interleukin-6, interleukin-1β, Wnt1, active β-catenin/total β-catenin ratio and fibronectin along with mRNA expression of RENIN, ACE and AT1 were increased in renal tissues. Treatment with either PA or LOS ameliorated all DOX-induced changes. The combined treatment was more effective in improving all changes than monotherapy.

CONCLUSIONS

These results suggest a new therapeutic benefit of PA in ameliorating CKD in rats through its up-regulatory effect on renal klotho thereby preventing Wnt/β-catenin reactivation and RAS gene expression. PA/LOS combination provided an additional inhibition of Wnt/β-catenin signalling and its downstream targets.

Elevated Ambulatory Blood Pressure Measurements are Associated with a Progressive Form of Fabry Disease

 INTRODUCTION: Published data on hypertension incidence and management in Anderson-Fabry disease are scant and the contribution of elevated blood pressure to organ damage is not well recognized.

AIM

Therefore, we have assessed blood pressure values and their possible correlations with clinical findings in a well described cohort of Fabry patients.

METHODS

Between January 2015 and May 2019, all adult Fabry patients (n = 24 females, n = 8 males) referred to our institute were prospectively enrolled. During the first examination patient's genotype and clinical characteristics were recorded. Blood pressure data were obtained by standard observed office measurements followed, within 6 months, by ambulatory blood pressure monitoring and home self-recordings. Organ involvement, including kidneys, heart and brain, was monitored over time. Consequently, patients were defined as clinically stable or progressive through the Fabry Stabilization Index.

RESULTS

The standard office measurements have diagnosed hypertension in three (9.37%) patients, but the ambulatory monitoring showed elevated blood pressure in six (18.75%) patients, revealing three cases of masked hypertension. All the hypertensive patients were females and, compared with normotensive subjects, they presented a lower glomerular filtration rate (p < 0.05) and a more advanced cardiac hypertrophy (p < 0.05). Four (66.7%) of them were diagnosed with a progressive form of the disease through the Fabry Stabilization Index while the majority of the normotensive group (84.6%, n = 19) was stable over time. No correlation was found between the prevalence of hypertension and the type of mutations causing Fabry disease.

CONCLUSION

Hypertension can be found in a restricted portion of clinically stable Fabry patients. In contrast, patients presenting with a progressive organ involvement, particularly renal impairment, have a major risk of developing uncontrolled blood pressure, and should be followed carefully. Moreover, the ambulatory blood pressure monitoring proved to be useful to reveal masked hypertension, which can contribute to the progressive worsening of the organ damage. Therefore, a proper diagnosis and therapy of hypertension may improve the outcome of Fabry patients.

Tamarind (Tamarindus indica L.) Seed a Candidate Protein Source with Potential for Combating SARS-CoV-2 Infection in Obesity

Introduction:

Obesity and coronavirus disease (COVID)-19 are overlapping pandemics, and one might worsen the other.

Methods:

This narrative review discusses one of the primary mechanisms to initiate acute respiratory distress syndrome, uncontrolled systemic inflammation in COVID-19, and presents a potential candidate for adjuvant treatment. Blocking the S protein binding to angiotensin-converting enzyme 2 (ACE-2) and the 3C-like protease (3CL ^pro) is an effective strategy against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

Results:

Host proteases such as FURIN, trypsin, and transmembrane serine protease 2 (TMPRSS) act in S protein activation. Tamarind trypsin inhibitor (TTI) shows several beneficial effects on the reduction of inflammatory markers (tumor necrosis factor α [TNF-α], leptin) and biochemical parameters (fasting glycemia, triglycerides, and very low-density lipoprotein [VLDL]), in addition to improving pancreatic function and mucosal integrity in an obesity model. TTI may inhibit the action of proteases that collaborate with SARS-CoV-2 infection and the neutrophil activity characteristic of lung injury promoted by the virus.

Conclusion:

Thus, TTI may contribute to combating two severe overlapping problems with high cost and social complex implications, obesity and COVID-19.

Correlation between bioactive lipids and novel coronavirus: constructive role of biolipids in curbing infectivity by enveloped viruses, centralizing on EPA and DHA

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) belongs to the family coronaviridae. It is spherical and possesses proteins called spikes, which can clamp onto the human cells. Once in close interaction with the human cells, these viruses undergo structural change and can fuse with the cell membrane. The virus enters the host and starts the process of translation and transcription in the cells and uncoated genome, respectively. Due to the rapid transmittable nature of the virus, extant actions should be taken. The fatty acids administrated orally, or intravenously, could help us gear things up in providing resistance and preventing infection. Hence, the multiplication of the virus could be hindered by arachidonic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). In that context, the current review highlights the role of these unsaturated fatty acids and their derivatives such as lipoxins and resolvins in the inactivation of the enveloped coronavirus disease 2019 (COVID-19).

Developmental Programming and Reprogramming of Hypertension and Kidney Disease: Impact of Tryptophan Metabolism

The concept that hypertension and chronic kidney disease (CKD) originate in early life has emerged recently. During pregnancy, tryptophan is crucial for maternal protein synthesis and fetal development. On one hand, impaired tryptophan metabolic pathway in pregnancy impacts fetal programming, resulting in the developmental programming of hypertension and kidney disease in adult offspring. On the other hand, tryptophan-related interventions might serve as reprogramming strategies to prevent a disease from occurring. In the present review, we aim to summarize (1) the three major tryptophan metabolic pathways, (2) the impact of tryptophan metabolism in pregnancy, (3) the interplay occurring between tryptophan metabolites and gut microbiota on the production of uremic toxins, (4) the role of tryptophan-derived metabolites-induced hypertension and CKD of developmental origin, (5) the therapeutic options in pregnancy that could aid in reprogramming adverse effects to protect offspring against hypertension and CKD, and (6) possible mechanisms linking tryptophan metabolism to developmental programming of hypertension and kidney disease.

Severity of Intrarenal Arterial Lesions Can Predict the Clinical Prognosis of Hepatitis B Virus-Associated Glomerulonephritis: A Retrospective Study

Background

Intrarenal arterial lesions (IALs) have been studied in immunoglobulin A nephropathy and lupus nephritis, but this has not been reported in hepatitis B virus-associated glomerulonephritis (HBV-GN). This study aims to investigate the prevalence and the role of IALs in HBV-GN.

Methods

IALs were examined in kidney biopsy specimens from 205 patients with HBV-GN retrospectively. The severity of IALs and tubular interstitial lesions was scored semi-quantitatively. The severity of IALs was divided into 4 groups on the basis of ILA score, which were no IALs (Score 0), mild IALs (Score 1-2), moderate IALs (Score 3-4), and severe IALs (Score 5-10) groups. Survival analysis was performed using the Kaplan-Meier method between the severity of IALs and clinical events (doubling of serum creatinine [SCr], ESRD, and death due to the kidney disease).

Results

Among 205 patients with HBV-GN, 143 (69.8%) had IALs in their kidney biopsy specimens. IALs were mild in 28 (19.6%) patients, moderate in 101 (70.6%) patients, and severe in 14 (9.8%) patients. The severity of IALs was associated with high blood pressure (BP), high SCr, and severe tubulointerstitial injuries. The average follow-up time of these 205 HBV-GN patients was 94.2 ± 47.1 months, in which 46 cases had clinical event. The proportions of clinical events in no IAL, mild IAL, moderate IAL, and severe IAL groups were 9.7, 14.3, 25.7, and 71.4%, respectively. Event-free survival of patient in IAL group was significantly lower than that in the no IAL group (p = 0.000). Multivariate cox regression analysis indicated SCr (1.011, 1.007-1.016), hypertension (1.767, 1.004-3.108), and IAL (2.194, 1.062-4.530) were independent risk factors for clinical events after adjustment for age and gender. Event-free clinical survival in moderate and severe IAL groups was significantly lower than that in the no IAL group (p = 0.0111 and p = 0.0001, respectively). Besides, event-free renal survival in severe IAL group was significantly lower than that in moderate IAL group (p = 0.009). Multivariate cox regression analysis showed that the more severe the IALs, the higher the risk of the clinical event, with a hazard ratio of 2.284 for moderate IALs (1.085-4.907) and 3.315 for severe IALs (1.296-8.482).

Conclusions

Severity of IALs is associated with high BP, reduced renal function, and poor clinical prognosis in HBV-GN patients.

The Interplay of Renin-Angiotensin System and Toll-Like Receptor 4 in the Inflammation of Diabetic Nephropathy

Diabetic nephropathy (DN) is one of the most serious chronic kidney diseases and the major cause of end-stage renal failure worldwide. The underlying mechanisms of DN are complex and required to be further investigated. Both innate immunity and renin-angiotensin system (RAS) play critical roles in the pathogenesis of DN. Except for traditional functions, abnormally regulated RAS has been proved to be involved in the inflammatory process of DN. Toll-like receptor 4 (TLR4) is the most deeply studied pattern recognition receptor in the innate immune system, and its activation has been reported to mediate the development of DN. In this review, we aim at discussing how dysregulated RAS affects TLR4 activation in the kidney that contributes to the exploration of the pathogenesis of DN. Understanding the interplay of RAS and TLR4 in inducing the progression of DN may provide new insights to develop effective treatments.

A More Oxidized Plasma Albumin Redox State and Lower Plasma HDL Particle Number Reflect Low-Protein Diet Ingestion in Adult Rats

BACKGROUND

Plasma albumin (ALB) redox state reflects protein nutritional status, but how it differs from other protein nutrition biomarkers remains to be fully elucidated.

OBJECTIVE

This study aimed to delineate the characteristics of plasma ALB redox state as a protein nutrition biomarker.

METHODS

Adult male Wistar rats were maintained on an AIN-93 M [14% casein, control (CT)] diet or an AIN-93 M-based 5% casein [low protein (LP)] diet ad libitum for 4 wk. Plasma samples were repeatedly obtained from the same rats at weeks 0-4, ALB redox state was determined by HPLC, and the concentrations of conventional protein nutrition biomarkers, ALB and transthyretin (TTR), were compared between the groups by Student t test. Body mass, relative muscle masses, plasma proteome, and plasma lipids at week 4 were also compared.

RESULTS

Plasma ALB redox state shifted to a more oxidized state in the LP diet group compared with the CT diet group at weeks 1-4. The LP diet group also showed significantly lower plasma ALB concentrations at weeks 1 and 2 (13% and 11% lower, respectively) and significantly lower TTR concentration at week 1 (21% lower) compared with the CT diet group, but these concentrations did not differ significantly at weeks 3 and 4. After 4 wk, body mass and relative soleus and gastrocnemius muscle masses did not differ, but the relative plantaris muscle mass tended to be 4% lower (1.75 compared with 1.68 g/kg body mass) in the LP diet group compared with the CT group (P = 0.06). The LP diet group also had a significantly lower HDL particle number than the CT group (30% lower).

CONCLUSIONS

A more oxidized plasma ALB redox state and lower plasma HDL particle number reflect LP diet ingestion in adult rats, which did not exhibit changes of plasma ALB and TTR concentrations.

Long-term expression of glomerular genes in diabetic nephropathy

Background

Although diabetic nephropathy (DN) is the most common cause for end-stage renal disease in western societies, its pathogenesis still remains largely unclear. A different gene pattern of diabetic and healthy kidney cells is one of the probable explanations. Numerous signalling pathways have emerged as important pathophysiological mechanisms for diabetes-induced renal injury.

Methods

Glomerular cells, as podocytes or mesangial cells, are predominantly involved in the development of diabetic renal lesions. While many gene assays concerning DN are performed with whole kidney or renal cortex tissue, we isolated glomeruli from black and tan, brachyuric (BTBR) obese/obese (ob/ob) and wildtype mice at four different timepoints (4, 8, 16 and 24 weeks) and performed an mRNA microarray to identify differentially expressed genes (DEGs). In contrast to many other diabetic mouse models, these homozygous ob/ob leptin-deficient mice develop not only a severe type 2 diabetes, but also diabetic kidney injury with all the clinical and especially histologic features defining human DN. By functional enrichment analysis we were able to investigate biological processes and pathways enriched by the DEGs at different disease stages. Altered expression of nine randomly selected genes was confirmed by quantitative polymerase chain reaction from glomerular RNA.

Results

Ob/ob type 2 diabetic mice showed up- and downregulation of genes primarily involved in metabolic processes and pathways, including glucose, lipid, fatty acid, retinol and amino acid metabolism. Members of the CYP4A and ApoB family were found among the top abundant genes. But more interestingly, altered gene loci showed enrichment for processes and pathways linked to angioneogenesis, complement cascades, semaphorin pathways, oxidation and reduction processes and renin secretion.

Conclusion

The gene profile of BTBR ob/ob type 2 diabetic mice we conducted in this study can help to identify new key players in molecular pathogenesis of diabetic kidney injury.

The role of pericytes in brain disorders: from the periphery to the brain

It is becoming increasingly apparent that disorders of the brain microvasculature contribute to many neurological disorders. In recent years it has become clear that a major player in these events is the capillary pericyte which, in the brain, is now known to control the blood-brain barrier, regulate blood flow, influence immune cell entry and be crucial for angiogenesis. In this review we consider the under-explored possibility that peripheral diseases which affect the microvasculature, such as hypertension, kidney disease and diabetes, produce central nervous system (CNS) dysfunction by mechanisms affecting capillary pericytes within the CNS. We highlight how cellular messengers produced peripherally can act via signalling pathways within CNS pericytes to reshape blood vessels, restrict blood flow or compromise blood-brain barrier function, thus causing neuronal dysfunction. Increased understanding of how renin-angiotensin, Rho-kinase and PDGFRβ signalling affect CNS pericytes may suggest novel therapeutic approaches to reducing the CNS effects of peripheral disorders.

Focus on 1,25-Dihydroxyvitamin D3 in the Peripheral Nervous System

In this review, we draw attention to the roles of calcitriol (1,25-dihydroxyvitamin D3) in the trophicity of the peripheral nervous system. Calcitriol has long been known to be crucial in phosphocalcium homeostasis. However, recent discoveries concerning its involvement in the immune system, anti-cancer defenses, and central nervous system development suggest a more pleiotropic role than previously thought. Several studies have highlighted the impact of calcitriol deficiency as a promoting factor of various central neurological diseases, such as multiple sclerosis, amyotrophic lateral sclerosis, Parkinson's disease, and Alzheimer's disease. Based on these findings and recent publications, a greater role for calcitriol may be envisioned in the peripheral nervous system. Indeed, calcitriol is involved in myelination, axonal homogeneity of peripheral nerves, and neuronal-cell differentiation. This may have useful clinical consequences, as calcitriol supplementation may be a simple means to avoid the onset and/or development of peripheral nervous-system disorders.

Wnt/β-catenin regulates blood pressure and kidney injury in rats

Activation of the renin-angiotensin system (RAS) plays a pivotal role in mediating hypertension, chronic kidney and cardiovascular diseases. As Wnt/β-catenin regulates multiple RAS genes, we speculated that this developmental signaling pathway might also participate in blood pressure (BP) regulation. To test this, we utilized two rat models of experimental hypertension: chronic angiotensin II infusion and remnant kidney after 5/6 nephrectomy. Inhibition of Wnt/β-catenin by ICG-001 blunted angiotensin II-induced hypertension. Interestingly, angiotensin II was able to induce the expression of multiple Wnt genes in vivo and in vitro, thereby creating a vicious cycle between Wnt/β-catenin and RAS activation. In the remnant kidney model, renal β-catenin was upregulated, and delayed administration of ICG-001 also blunted BP elevation and abolished the induction of angiotensinogen, renin, angiotensin-converting enzyme and angiotensin II type 1 receptor. ICG-001 also reduced albuminuria, serum creatinine and blood urea nitrogen, and inhibited renal expression of fibronectin, collagen I and plasminogen activator inhibitor-1, and suppressed the infiltration of CD3⁺ T cells and CD68⁺ monocytes/macrophages. In vitro, incubation with losartan prevented Wnt/β-catenin-mediated fibronectin, α-smooth muscle actin and Snail1 expression, suggesting that the fibrogenic action of Wnt/β-catenin is dependent on RAS activation. Taken together, these results suggest an intrinsic linkage of Wnt/β-catenin signaling with BP regulation. Our studies also demonstrate that hyperactive Wnt/β-catenin can drive hypertension and kidney damage via RAS activation.

Rapeseed protein-derived peptides, LY, RALP, and GHS, modulates key enzymes and intermediate products of renin-angiotensin system pathway in spontaneously hypertensive rat

Rapeseed proteins are a rich source of bioactive peptides. LY, RALP and GHS were previously identified from rapeseed protein hydrolysates as potent ACE and renin inhibiting peptides. In this study, the rapeseed peptides were individually evaluated for their molecular mechanisms and regulatory effects on components of the renin-angiotensin system in spontaneously hypertensive rats (SHR), including the mRNA and/or protein levels of angiotensin-converting enzyme (ACE), renin, ACE2, angiotensin II and angiotensin-(1-7) in myocardial tissues. Oral administration of 30 mg peptides/kg body weight every 2 days for five weeks significantly decreased the systolic blood pressure and the myocardial mRNA and protein levels of ACE and renin in SHR. LY, RALP and GHS also increased the expression of ACE2, angiotensin-(1-7) and Mas receptor levels, which may have mediated their antihypertensive activity. Dipeptide LY also inhibited angiotensin II protein expression in the heart tissue. Taken together, the finding demonstrates the multi-target physiological effects of the rapeseed peptides, beyond ACE and renin inhibition, which enhances knowledge of the antihypertensive mechanisms of food protein-derived peptides.

Investigating the RAS can be a fishy business: interdisciplinary opportunities using Zebrafish

The renin-angiotensin system (RAS) is highly conserved, and components of the RAS are present in all vertebrates to some degree. Although the RAS has been studied since the discovery of renin, its biological role continues to broaden with the identification and characterization of new peptides. The evolutionarily distant zebrafish is a remarkable model for studying the kidney due to its genetic tractability and accessibility for in vivo imaging. The zebrafish pronephros is an especially useful kidney model due to its structural simplicity yet complex functionality, including capacity for glomerular and tubular filtration. Both the pronephros and mesonephros contain renin-expressing perivascular cells, which respond to RAS inhibition, making the zebrafish an excellent model for studying the RAS. This review summarizes the physiological and genetic tools currently available for studying the zebrafish kidney with regards to functionality of the RAS, using novel imaging techniques such as SPIM microscopy coupled with targeted single cell ablation and synthesis of vasoactive RAS peptides.

Altered Circadian Timing System-Mediated Non-Dipping Pattern of Blood Pressure and Associated Cardiovascular Disorders in Metabolic and Kidney Diseases

The morning surge in blood pressure (BP) coincides with increased cardiovascular (CV) events. This strongly suggests that an altered circadian rhythm of BP plays a crucial role in the development of CV disease (CVD). A disrupted circadian rhythm of BP, such as the non-dipping type of hypertension (i.e., absence of nocturnal BP decline), is frequently observed in metabolic disorders and chronic kidney disease (CKD). The circadian timing system, controlled by the central clock in the suprachiasmatic nucleus of the hypothalamus and/or by peripheral clocks in the heart, vasculature, and kidneys, modulates the 24 h oscillation of BP. However, little information is available regarding the molecular and cellular mechanisms of an altered circadian timing system-mediated disrupted dipping pattern of BP in metabolic disorders and CKD that can lead to the development of CV events. A more thorough understanding of this pathogenesis could provide novel therapeutic strategies for the management of CVD. This short review will address our and others' recent findings on the molecular mechanisms that may affect the dipping pattern of BP in metabolic dysfunction and kidney disease and its association with CV disorders.

Irradiation enhanced risks of hospitalised pneumonopathy in lung cancer patients: a population-based surgical cohort study

OBJECTIVE

Pulmonary radiotherapy has been reported to increase a risk of pneumonopathy, including pneumonitis and secondary pneumonia, however evidence from population-based studies is lacking. The present study intended to explore whether postoperative irradiation increases occurrence of severe pneumonopathy in lung cancer patients.

DESIGN, SETTING AND PARTICIPANTS

The nationwide population-based study analysed the Taiwan National Health Insurance Research Database (covered >99% of Taiwanese) in a real-world setting. From 2000 to 2010, 4335 newly diagnosed lung cancer patients were allocated into two groups: surgery-RT (n=867) and surgery-alone (n=3468). With a ratio of 1:4, propensity score was used to match 11 baseline factors to balance groups.

INTERVENTIONS/EXPOSURES

Irradiation was delivered to bronchial stump and mediastinum according to peer-audited guidelines.

OUTCOMES/MEASURES

Hospitalised pneumonia/pneumonitis-free survival was the primary end point. Risk factors and hazard effects were secondary measures.

RESULTS

Multivariable analysis identified five independent risk factors for hospitalised pneumonopathy: elderly (>65 years), male, irradiation, chronic obstructive pulmonary disease (COPD) and chronic kidney disease (CKD). Compared with surgery-alone, a higher risk of hospitalised pneumonopathy was found in surgery-RT patients (HR, 2.20; 95% CI, 1.93-2.51; 2-year hospitalised pneumonia/pneumonitis-free survival, 85.2% vs 69.0%; both p<0.0001), especially in elderly males with COPD and CKD (HR, 13.74; 95% CI, 6.61-28.53; p<0.0001). Unexpectedly, we observed a higher risk of hospitalised pneumonopathy in younger irradiated-CKD patients (HR, 13.07; 95% CI, 5.71-29.94; p<0.0001) than that of elderly irradiated-CKD patients (HR, 4.82; 95% CI, 2.88-8.08; p<0.0001).

CONCLUSIONS

A high risk of hospitalised pneumonopathy is observed in irradiated patients, especially in elderly males with COPD and CKD. For these patients, close clinical surveillance and aggressive pneumonia/pneumonitis prevention should be considered. Further investigations are required to define underlying biological mechanisms, especially for younger CKD patients.

RAS Genetic Variants in Interaction with ACE Inhibitors Drugs Influences Essential Hypertension Control

BACKGROUNDS AND AIMS

Essential Hypertension (EH) is a common disorder associated with increased cardiovascular morbidity and mortality in Malaysia. To investigate how genetic polymorphisms of the renin-angiotensin-aldosterone system (RAS) influence EH control with angiotensin-converting enzyme inhibitor drugs (ACEI).

METHODS

A case-control, cross-sectional population-based nested study (n = 142) included hypertensive subjects treated with ACEI drugs, either lisinopril or enalapril (20 mg, once daily) as monotherapy for 24 weeks. In total seven possible polymorphisms of RAS genes were genotyped. The association between those polymorphisms and the changes in blood pressure were observed in the 24 week treatment.

RESULTS

Statistically significant associations of I, G, T, M and G alleles of ACE (I/D, G2350A), AGT (M235T, T175M and G-6A) respectively were observed in essential hypertensive subjects. The decrease in systolic blood pressure and diastolic blood pressure after 24 weeks of treatment of the patients carrying II, GG, and TT genotypes were greater than the groups carrying DD, AA, MM, MM and GG of I/D, G2350A, M235T, T174M and G-6A genotypes respectively. In contrast, No significant difference was observed between renin gene polymorphisms (Bg/I and MboI) and hypertensives.

CONCLUSIONS

Although this study shows a possible association of polymorphisms of RAS genes with the risk of non-control of HT in ACEI-treated patients and indicates the importance of all this system's components in regulating HT, it needs to be replicated in other data sources.

Wnt/β-catenin signaling and renin-angiotensin system in chronic kidney disease

PURPOSE OF REVIEW

Intrarenal activation of the renin-angiotensin system (RAS) plays an essential role in the pathogenesis of hypertension and chronic kidney diseases (CKD). However, how RAS genes are regulated in vivo was poorly understood until recently. This review focuses on recent findings of the transcriptional regulation of RAS components, as well as their implication in developing novel strategies to treat the patients with CKD.

RECENT FINDINGS

Bioinformatics analyses have uncovered the presence of putative binding sites for T-cell factor/β-catenin in the promoter region of all RAS genes. Both in-vitro and in-vivo studies confirm that Wnt/β-catenin is the master upstream regulator that controls the expression of all RAS components tested, such as angiotensinogen, renin, angiotensin converting enzyme and the angiotensin II type I receptor in the kidney. Targeted inhibition of Wnt/β-catenin, by either small molecule ICG-001 or endogenous Wnt antagonist Klotho, represses RAS activation and ameliorates proteinuria and kidney injury. Blockade of Wnt/β-catenin signaling also normalizes blood pressure in a mouse model of CKD.

SUMMARY

These recent studies identify Wnt/β-catenin as the master regulator that controls multiple RAS genes, and suggest that targeting this upstream signaling could be an effective strategy for the treatment of patients with hypertension and CKD.

Homocysteine and hydrogen sulfide in epigenetic, metabolic and microbiota related renovascular hypertension

Over the past several years, hydrogen sulfide (H₂S) has been shown to be an important player in a variety of physiological functions, including neuromodulation, vasodilation, oxidant regulation, inflammation, and angiogenesis. H₂S is synthesized primarily through metabolic processes from the amino acid cysteine and homocysteine in various organ systems including neuronal, cardiovascular, gastrointestinal, and kidney. Derangement of cysteine and homocysteine metabolism and clearance, particularly in the renal vasculature, leads to H₂S biosynthesis deregulation causing or contributing to existing high blood pressure. While a variety of environmental influences, such as diet can have an effect on H₂S regulation and function, genetic factors, and more recently epigenetics, also have a vital role in H₂S regulation and function, and therefore disease initiation and progression. In addition, new research into the role of gut microbiota in the development of hypertension has highlighted the need to further explore these microorganisms and how they influence the levels of H₂S throughout the body and possibly exploiting microbiota for use of hypertension treatment. In this review, we summarize recent advances in the field of hypertension research emphasizing renal contribution and how H₂S physiology can be exploited as a possible therapeutic strategy to ameliorate kidney dysfunction as well as to control blood pressure.

Sonic hedgehog signaling in kidney fibrosis: a master communicator

The hedgehog signaling cascade is an evolutionarily conserved pathway that regulates multiple aspects of embryonic development and plays a decisive role in tissue homeostasis. As the best studied member of three hedgehog ligands, sonic hedgehog (Shh) is known to be associated with kidney development and tissue repair after various insults. Recent studies uncover an intrinsic link between dysregulated Shh signaling and renal fibrogenesis. In various types of chronic kidney disease (CKD), Shh is upregulated specifically in renal tubular epithelium but targets interstitial fibroblasts, thereby mediating a dynamic epithelial- mesenchymal communication (EMC). Tubule-derived Shh acts as a growth factor for interstitial fibroblasts and controls a hierarchy of fibrosis-related genes, which lead to the excessive deposition of extracellular matrix in renal interstitium. In this review, we recapitulate the principle of Shh signaling, its activation and regulation in a variety of kidney diseases. We also discuss the potential mechanisms by which Shh promotes renal fibrosis and assess the efficacy of blocking this signaling in preclinical settings. Continuing these lines of investigations will provide novel opportunities for designing effective therapies to improve CKD prognosis in patients.

N-acetylcysteine alleviates angiotensin II-mediated renal fibrosis in mouse obstructed kidneys

AIM

To investigate the effects of ROS scavenger N-acetylcysteine (NAC) on angiotensin II (Ang II)-mediated renal fibrosis in vivo and in vitro.

METHODS

Mice were subjected to unilateral ureteral obstruction (UUO), and then treated with vehicle or NAC (250 mg/kg, ip) for 7 days. Histological changes of the obstructed kidneys were observed with Masson's trichrome staining. ROS levels were detected with DHE staining. The expression of relevant proteins in the obstructed kidneys was assessed using Western blotting assays. Cultured rat renal fibroblast NRK-49F cells were used for in vitro experiments.

RESULTS

In the obstructed kidneys, Ang II levels were significantly elevated, and collagen I was accumulated in the interstitial spaces. Furthermore, ROS production and the expression of p47 (a key subunit of NADPH oxidase complexes) were increased in a time-dependent manner; the expression of fibronectin, α-SMA and TGF-β were upregulated. Administration of NAC significantly alleviated the fibrotic responses in the obstructed kidneys. In cultured NRK-49F cells, treatment with Ang II (0.001-10 μmol/L) increased the expression of fibronectin, collagen I, α-SMA and TGF-β in dose-dependent and time-dependent manners. Ang II also increased ROS production and the phosphorylation of Smad3. Pretreatment with NAC (5 μmol/L) blocked Ang II-induced oxidative stress and ECM production in the cells.

CONCLUSION

In mouse obstructed kidneys, the fibrotic responses result from Ang II upregulation can be alleviated by the ROS scavenger N-acetylcysteine.

Genomics in CKD: Is This the Path Forward?

Recent advances in genomics and sequencing technology have led to a better understanding of genetic risk in CKD. Genetics could account in part for racial differences in treatment response for medications including antihypertensives and immunosuppressive medications due to its correlation with ancestry. However, there is still a substantial lag between generation of this knowledge and its adoption in routine clinical care. This review summarizes the recent advances in genomics and CKD, discusses potential reasons for its underutilization, and highlights potential avenues for application of genomic information to improve clinical care and outcomes in this particularly vulnerable population.

Klotho Ameliorates Kidney Injury and Fibrosis and Normalizes Blood Pressure by Targeting the Renin-Angiotensin System

Loss of Klotho and activation of the renin-angiotensin system (RAS) are common pathological findings in chronic kidney diseases. However, whether these two events are intricately connected is poorly understood. We hypothesized that Klotho might protect kidneys by targeted inhibition of RAS activation in diseased kidneys. To test this hypothesis, mouse models of remnant kidney, as well as adriamycin nephropathy and unilateral ureteral obstruction, were utilized. At 6 weeks after 5/6 nephrectomy, kidney injury was evident, characterized by elevated albuminuria and serum creatinine levels, and excessive deposition of interstitial matrix proteins. These lesions were accompanied by loss of renal Klotho expression, up-regulation of RAS components, and development of hypertension. In vivo expression of exogenous Klotho through hydrodynamic-based gene delivery abolished the induction of multiple RAS proteins, including angiotensinogen, renin, angiotensin-converting enzyme, and angiotensin II type 1 receptor, and normalized blood pressure. Klotho also inhibited β-catenin activation and ameliorated renal fibrotic lesions. Similar results were obtained in mouse models of adriamycin and obstructive nephropathy. In cultured kidney tubular epithelial cells, Klotho dose-dependently blocked Wnt1-triggered RAS activation. Taken together, these results demonstrate that Klotho exerts its renal protection by targeted inhibition of RAS, a pathogenic pathway known to play a key role in the evolution and progression of hypertension and chronic kidney disorders.

Role of pharmacogenomics in dialysis and transplantation

PURPOSE OF REVIEW

Pharmacogenomics is the study of differences in drug response on the basis of individual genetic background. With rapidly advancing genomic technologies and decreased costs of genotyping, the field of pharmacogenomics continues to develop. Application to patients with kidney disease provides growing opportunities for improving drug therapy.

RECENT FINDINGS

Pharmacogenomics studies are lacking in patients with chronic kidney disease and dialysis, but are abundant in the kidney transplant field. A potentially clinically actionable genetic variant exists in the CYP3A5 gene, with the initial tacrolimus dose selection being optimized based on CYP3A5 genotype. Although many pharmacogenomics studies have focused on transplant immunosuppression pharmacokinetics, an expanding literature on pharmacodynamic outcomes, such as calcineurin inhibitor toxicity and new onset diabetes, is providing new information on patients at risk.

SUMMARY

Appropriately powered pharmacogenomics studies with well-defined phenotypes are needed to validate existing studies and unearth new findings in patients with kidney disease, especially the chronic kidney disease and dialysis population.

Wnt/β-catenin signalling and podocyte dysfunction in proteinuric kidney disease

Podocytes are unique, highly specialized, terminally differentiated cells that are integral components of the kidney glomerular filtration barrier. Podocytes are vulnerable to a variety of injuries and in response they undergo a series of changes ranging from hypertrophy, autophagy, dedifferentiation, mesenchymal transition and detachment to apoptosis, depending on the nature and extent of the insult. Emerging evidence indicates that Wnt/β-catenin signalling has a central role in mediating podocyte dysfunction and proteinuria. Wnts are induced and β-catenin is activated in podocytes in various proteinuric kidney diseases. Genetic or pharmacologic activation of β-catenin is sufficient to impair podocyte integrity and causes proteinuria in healthy mice, whereas podocyte-specific ablation of β-catenin protects against proteinuria after kidney injury. Mechanistically, Wnt/β-catenin controls the expression of several key mediators implicated in podocytopathies, including Snail1, the renin-angiotensin system and matrix metalloproteinase 7. Wnt/β-catenin also negatively regulates Wilms tumour protein, a crucial transcription factor that safeguards podocyte integrity. Targeted inhibition of Wnt/β-catenin signalling preserves podocyte integrity and ameliorates proteinuria in animal models. This Review highlights advances in our understanding of the pathomechanisms of Wnt/β-catenin signalling in mediating podocyte injury, and describes the therapeutic potential of targeting this pathway for the treatment of proteinuric kidney disease.

Anti-hypertensive and renoprotective effects of berberine in spontaneously hypertensive rats

OBJECTIVES

We aimed to investigate the effects of berberine on renin-angiotensin system (RAS) and pro-inflammatory cytokines, as well as its effects on blood pressure and renal damage in spontaneously hypertensive rats.

METHODS

Berberine was administrated to spontaneously hypertensive rats (SHR rats) between 3 and 20 weeks of age. Blood pressure was monitored in 3-, 6-, 9-, 12-, 16- and 20-week-old SHR rats and age-matched Wistar Kyoto rats (WKY rats). Besides, we measured levels of angiotensin II, aldosterone and pre-inflammatory cytokines (IL-6, IL-17, IL-23) in serum and kidney, as well as levels of collagen III and collagen IV in kidney and urinary markers of renal injury (osteopontin, kidney-injury-molecule (KIM-1) and albumin) in 3-, 6-, 9-, 12-, 16- and 20-week-old SHR rats and WKY rats. Glomerulosclerosis was also assessed with hematoxylin and eosin staining.

RESULTS

SHR rats developed hypertension at the age of 6 weeks and had increased levels of angiotensin II, aldosterone, IL-6, IL-17, IL-23, collagen III, collagen IV, osteopontin, KIM-1 and albumin, as well as more severe glomerulosclerosis, compared to the aged-matched WKY rats. Berberine delayed the onset and attenuated the severity of hypertension, as well as partially inhibited the increases of the above substances in SHR rats.

CONCLUSION

Berberine could delay the onset and attenuate the severity of hypertension, as well as ameliorate hypertension-induced renal damage in SHR rats. Furthermore, berberine could inhibit the activities of RAS and pre-inflammatory cytokines IL-6, IL-17 and IL-23, which are involved in the pathophysiology of hypertension.

Qian Yang Yu Yin Granule-containing serum inhibits angiotensin II-induced proliferation, reactive oxygen species production, and inflammation in human mesangial cells via an NADPH oxidase 4-dependent pathway

Background

Qian Yang Yu Yin Granule (QYYYG), a traditional Chinese herbal medicine, has been indicated for renal damage in hypertension for decades in China, but little remains known regarding its underlying molecular mechanism. Therefore, we performed the current study in order to investigate the underlying molecular mechanism of QYYYG in the treatment of hypertensive renal damage.

Methods

We hypothesize that QYYYG relieves hypertensive renal injury through an angiotensin II (Ang II)-nicotinamide adenine dinucleotide phosphate (NAPDH)-oxidase (NOX)-reactive oxygen species (ROS) pathway. In this study, we investigated the effects of QYYYG-containing serum (QYGS) in human mesangial cells (HMCs) against Ang II-induced cell proliferation, ROS production, and inflammation through the seropharmacological method.

Results

We found that QYGS could inhibit cell proliferation in Ang II-treated HMCs. In addition, QYGS considerably suppressed production of ROS, decreased mRNA and protein expression of NAPDH-oxidase 4 (NOX4), p22^phox, and activated Ras-related C3 botulinum toxin substrate 1 (GTP-Rac1); as well as counteracted the up-regulation of inflammatory markers including tumor necrosis factor-α (TNF-α), nuclear factor-κB (NF-κB) p65, and interleukin 6 (IL-6). These effects were further confirmed in HMCs transfected with specific small interfering RNA (siRNA) targeting NOX4.

Conclusions

Taken together, these results suggest that a NOX4-dependent pathway plays an important role in regulating the inhibitory effect of QYGS. Our findings provide new insights into the molecular mechanisms of QYYYG and their role in the treatment of hypertensive nephropathy.

Chronic stress improves NO- and Ca2+ flux-dependent vascular function: a pharmacological study

Background

Stress is associated with cardiovascular diseases.

Objective

This study aimed at assessing whether chronic stress induces vascular alterations, and whether these modulations are nitric oxide (NO) and Ca2+ dependent.

Methods

Wistar rats, 30 days of age, were separated into 2 groups: control (C) and Stress (St). Chronic stress consisted of immobilization for 1 hour/day, 5 days/week, 15 weeks. Systolic blood pressure was assessed. Vascular studies on aortic rings were performed. Concentration-effect curves were built for noradrenaline, in the presence of L-NAME or prazosin, acetylcholine, sodium nitroprusside and KCl. In addition, Ca²⁺ flux was also evaluated.

Results

Chronic stress induced hypertension, decreased the vascular response to KCl and to noradrenaline, and increased the vascular response to acetylcholine. L-NAME blunted the difference observed in noradrenaline curves. Furthermore, contractile response to Ca²⁺ was decreased in the aorta of stressed rats.

Conclusion

Our data suggest that the vascular response to chronic stress is an adaptation to its deleterious effects, such as hypertension. In addition, this adaptation is NO- and Ca²⁺-dependent. These data help to clarify the contribution of stress to cardiovascular abnormalities. However, further studies are necessary to better elucidate the mechanisms involved in the cardiovascular dysfunction associated with stressors. (Arq Bras Cardiol. 2014; [online].ahead print, PP.0-0)

The evaluation of involvement of angiotensin II, its receptors, and androgen receptor in endometrial cancer

Endometrial cancer (EC) is the most common gynecological malignancy. Alterations of angiogenic factors including angiotensin (AngII) or VEGF are observed in EC. Expression of angiotensin receptor 1 (AT1) is correlated with EC. Moreover, the expression of VEGF is up-regulated by AngII. Androgens are involved in the pathogenesis of EC. Genetic variations in androgen receptor (AR) gene may increase EC risk. This review proved strong correlation among EC, AngII, its receptors and AR, where AT influence on AR and, as a result, induce the expression of genes related to carcinogenesis.