Hypertension in Page (cellophane-wrapped) kidney is due to interstitial nephritis

Renal functional and cardiovascular outcomes of partial nephrectomy versus radical nephrectomy for renal tumors: a systematic review and meta-analysis

This systematic review and meta-analysis aimed to evaluate the postoperative renal and cardiovascular outcomes of partial nephrectomy (PN) versus radical nephrectomy (RN) for the treatment of renal carcinoma. A systematic literature search was performed on scientific databases including Scopus, Web of Science, MEDLINE, and EMBASE from their inception to September 2021. Studies comparing renal and cardiovascular outcomes between PN and RN in patients with renal cancer were included. The generic inverse variance method with random-effects models was used to determine the pooled hazard ratios and odds ratio for each outcome. Quality Assessment for observational studies was guided by the New-Castle Ottawa Scale. Overall, a total of 31 studies (n=51,866) reported renal outcomes, while 11 studies (n= 101,678) reported cardiovascular outcomes. When compared to PN, RN had a higher rate of new-onset postoperative EGFR <60 mL/min/1.73 m² (HR 3.39; CI 2.45 - 4.70; I²=93%; P=<0.00001) and EGFR <45 mL/min/1.73 m² (HR 4.70; CI 2.26 - 9.79; I²=98%; P=<0.0001). No difference was observed in new-onset advanced kidney disease and end-stage renal disease. A 19% reduction in cardiovascular events was observed in the PN group (HR 0.81; CI 0.70 - 0.93, P=0.002). No protective effect of PN was observed in new-onset or worsening hypertension (HR 0.85; CI 0.64 - 1.14, P=0.28) nor myocardial infarction (HR 0.86; CI 0.71 - 1.04, P=0.13). PN was associated with a decreased risk of postoperative early-stage CKD and cardiovascular events compared with RN. However, no benefit of PN over RN was observed in advanced CKD, new-onset or worsening hypertension, myocardial infarction, and cardiovascular mortality.

Non-dipping pulse rate and chronic changes of the kidney in patients with chronic kidney disease

Introduction

An insufficient decrease in nocturnal pulse rate (PR), non-dipping PR, reflects autonomic imbalance and is associated with cardiovascular events and all-cause mortality. We aimed to investigate the clinical and microanatomical structural findings associated with the non-dipping PR status in patients with chronic kidney disease (CKD).

Methods

This cross-sectional study included 135 patients who underwent ambulatory blood pressure monitoring and kidney biopsy concurrently at our institution between 2016 and 2019. Non-dipping PR status was defined as (daytime PR-nighttime PR)/daytime PR <0.1. We compared clinical parameters and microstructural changes in the kidney between patients with and without non-dipping PR, including 24 h proteinuria, glomerular volume, and Mayo Clinic/Renal Pathology Society Chronicity Score.

Results

The median age was 51 years (interquartile range: 35-63), 54% of which were male, and the median estimated glomerular filtration rate was 53.0 (30.0-75.0) mL/min/1.73 m². Non-dipping PR status was observed in 39 patients. Patients with non-dipping PR were older and had worse kidney function, higher blood pressure, greater prevalence of dyslipidemia, lower hemoglobin levels, and a larger amount of urinary protein excretion than patients with dipping PR. Patients with non-dipping PR had more severe glomerulosclerosis, interstitial fibrosis, tubular atrophy, and arteriosclerosis. In the multivariable analysis, the severe chronic changes of the kidney were associated with non-dipping PR status after adjusting for age, sex, and other clinical parameters (odds ratio = 20.8; 95% confidence interval, 2.82-153; P = 0.003).

Conclusion

This study is the first to indicate that non-dipping PR is significantly associated with chronic microanatomical changes in the kidneys of patients with CKD.

Should Renal Inflammation Be Targeted While Treating Hypertension?

Despite extensive research and a plethora of therapeutic options, hypertension continues to be a global burden. Understanding of the pathological roles of known and underexplored cellular and molecular pathways in the development and maintenance of hypertension is critical to advance the field. Immune system overactivation and inflammation in the kidneys are proposed alternative mechanisms of hypertension, and resistant hypertension. Consideration of the pathophysiology of hypertension in chronic inflammatory conditions such as autoimmune diseases, in which patients present with autoimmune-mediated kidney inflammation as well as hypertension, may reveal possible contributors and novel therapeutic targets. In this review, we 1) summarize current therapies used to control blood pressure and their known effects on inflammation; 2) provide evidence on the need to target renal inflammation, specifically, and especially when first-line and combinatory treatment efforts fail; and 3) discuss the efficacy of therapies used to treat autoimmune diseases with a hypertension/renal component. We aim to elucidate the potential of targeting renal inflammation in certain subsets of patients resistant to current therapies.

Tourette syndrome associated with Page kidney

BACKGROUND

Page kidney is a rare condition leading to secondary hypertension and encountered most frequently due to traumatic subcapsular hematoma. Here, we present a case of a 15-year-old boy with a history of Tourette syndrome, who had Page kidney hypertension secondary to subcapsular hematoma compression due to his self-injury behavior for many years.

Incidence and Risk Factors of Hypertension Following Partial Nephrectomy in Patients With Renal Tumors: A Cross-sectional Study of Postoperative Home Blood Pressure and Antihypertensive Medications

INTRODUCTION

We aimed to evaluate the incidence and risk factors for nephrectomy-related hypertension (NR-HT) in patients with renal tumors who underwent partial nephrectomy (PN) or radical nephrectomy (RN).

PATIENTS AND METHODS

A retrospective cross-sectional follow-up survey of postoperative home blood pressure (BP) and defined daily dose (DDD) of antihypertensive medications was conducted in patients with renal tumors who underwent PN (210 patients) or RN (120 patients), and they were compared. We evaluated the incidence and risk factors for NR-HT, defined as the addition of antihypertensive medications in doses of 1 DDD or more after surgery, or postoperative BP of 140/90 mmHg with an increase of 20 mmHg from preoperative BP with no reduction in dose of antihypertensive medications.

RESULTS

Both systolic (mean, 124 vs. 129 mmHg; P < .001) and diastolic BP (mean, 74 vs. 79 mmHg; P < .001) significantly increased after PN compared with RN. Systolic (P < .001) and diastolic (P = .003) BP increased significantly more after PN than after RN, and NR-HT was more frequent after PN than after RN (16% vs. 5%; P = .002). PN (odds ratio [OR], 2.93; P = .022) and higher postoperative peak C-reactive protein (OR, 2.34; P = .017) were independently associated with NR-HT. When limited to only the patients who underwent PN, acute kidney injury (OR, 2.65; P = .036) and higher postoperative peak C-reactive protein (OR, 2.54; P = .016) were independent risk factors for NR-HT.

CONCLUSION

PN may cause postoperative progression of hypertension possibly through renal parenchymal damage.

Models of Intrauterine growth restriction and fetal programming in rabbits

Intrauterine growth restriction (IUGR) affects approximately 10% of human pregnancies globally and has immediate and life-long consequences for offspring health. However, the mechanisms underlying the pathogenesis of IUGR and its association with later health and disease outcomes are poorly understood. To address these knowledge gaps, the use of experimental animals is critically important. Since the 50's different environmental, pharmacological, and surgical manipulations have been performed in the rabbit to improve our knowledge of the control of fetal growth, fetal responses to IUGR, and mechanisms by which offspring may be programmed by an adverse gestational environment. The purpose of this review is therefore to summarize the utility of the rabbit as a model for IUGR research. It first summarizes the knowledge of prenatal and postnatal development in the rabbit and how these events relate to developmental milestones in humans. It then describes the methods used to induce IUGR in rabbits and the knowledge gained about the mechanisms determining prenatal and postnatal outcomes of the offspring. Finally, it discusses the application of state of the art approaches in the rabbit, including high-resolution ultrasound, magnetic resonance imaging, and gene targeting, to gain a deeper integrative understanding of the physiological and molecular events governing the development of IUGR. Overall, we hope to engage and inspire investigators to employ the rabbit as a model organism when studying pregnancy physiology so that we may advance our understanding of mechanisms underlying IUGR and its consequences in humans and other mammalian species.

The bidirectional interaction between the sympathetic nervous system and immune mechanisms in the pathogenesis of hypertension

Over the last few years, evidence has accumulated to suggest that hypertension is, at least in part, an immune-mediated inflammatory disorder. Many links between immunity and hypertension have been established and provide a complex framework of mechanistic interactions contributing to the rise in BP. These include immune-mediated inflammatory processes affecting regulatory brain nuclei and interactions with other mediators of cardiovascular regulation such as the sympathetic nervous system. Sympathoexcitation differentially regulates T-cells based upon activation status of the immune cell as well as the resident organ. Exogenous and endogenous triggers activate signalling pathways in innate and adaptive immune cells resulting in pro-inflammatory cytokine production and activation of T-lymphocytes in the cardiovascular and renal regions, now considered major factors in the development of essential hypertension. The inflammatory cascade is sustained and exacerbated by the immune flow via the brain-bone marrow-spleen-gastrointestinal axis and thereby further aggravating immune-mediated pathways resulting in a vicious cycle of established hypertension and target organ damage. This review summarizes the evidence and recent advances in linking immune-mediated inflammation, sympathetic activation and their bidirectional interactions with the development of hypertension. LINKED ARTICLES: This article is part of a themed section on Immune Targets in Hypertension. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.12/issuetoc.

Protective effect of tetrahydrobiopterin on hepatic and renal damage after acute cadmium exposure in male rats

Cadmium (Cd) has been recognized as one of the most important environmental and industrial pollutants. This study investigated the impact of acute exposure to Cd on oxidative stress and the inflammatory marker interleukin-6 (IL-6) in the plasma of rats and the histological picture of liver and kidney, as well as to examine the potential protective effect of tetrahydrobiopterin (BH4).

METHODS

Rats were divided into control group, Cd group that received a single intraperitoneal (i.p.) dose of 4 mg/kg b.w. of CdCl2 and BH4+ Cd group that received a single dose of BH4 (20 mg/kg, i.p.) and subsequently exposed to a single dose of Cd 24 h after the BH4 treatment.

RESULTS

Cd increased the plasma levels of hepatic enzymes (ALT and AST), urea, creatinine, malondialdehyde (MDA), and IL-6 and decreased the superoxide dismutase (SOD) activity. Also, it induced histopathological alterations in the liver with severe degeneration, especially in centrilobular zones. Renal tubular epithelium showed vacuolated cytoplasm and dense nuclei. VEGF expression was mild. Ultrastuctural changes were seen in some renal tubules. The nuclei appeared distorted with electron dense chromatin. Mitochondria with destructed cristae were observed. BH4 pretreatment had protective effects, since it significantly reduced the levels of IL-6 and ameliorated the alteration in oxidative status biomarkers induced by Cd. Improvement of histopathological alterations was observed in Cd-groups. The nuclei were vesicular euchromatic, intact mitochondria and normal appearance of the filtration membrane. Moderate expression of VEGF was noted.

CONCLUSION

This study has provided clear evidence for the protective efficacy of BH4 against experimental Cd toxicity.

Interplay between the renin-angiotensin system, the canonical WNT/β-catenin pathway and PPARγ in hypertension

PURPOSE OF REVIEW

Heterogeneous causes can determinate hypertension.

RECENT FINDINGS

The renin-angiotensin system (RAS) has a major role in the pathophysiology of blood pressure. Angiotensin II and aldosterone are overexpressed during hypertension and lead to hypertension development and its cardiovascular complications. In several tissues, the overactivation of the canonical WNT/β-catenin pathway leads to inactivation of peroxisome proliferator-activated receptor gamma (PPARγ), while PPARγ stimulation induces a decrease of the canonical WNT/β-catenin pathway. In hypertension, the WNT/β-catenin pathway is upregulated, whereas PPARγ is decreased. The WNT/β-catenin pathway and RAS regulate positively each other during hypertension, whereas PPARγ agonists can decrease the expression of both the WNT/β-catenin pathway and RAS. We focus this review on the hypothesis of an opposite interplay between PPARγ and both the canonical WNT/β-catenin pathway and RAS in regulating the molecular mechanism underlying hypertension. The interactions between PPARγ and the canonical WNT/β-catenin pathway through the regulation of the renin-angiotensin system in hypertension may be an interesting way to better understand the actions and the effects of PPARγ agonists as antihypertensive drugs.

Transcutaneous glomerular filtration rate measurement in a canine animal model of chronic kidney disease

INTRODUCTION

Quantitative assessment of renal function by measurement of glomerular filtration rate (GFR) is an important part of safety and efficacy evaluation in preclinical drug development. Existing methods are often time consuming, imprecise and associated with animal burden. Here we describe the comparison between GFR determinations with sinistrin (PS-GFR) and fluorescence-labelled sinistrin-application and its transcutaneous detection (TD-GFR) in a large animal model of chronic kidney disease (CKD).

METHODS

TD-GFR measurements compared to a standard method using i.v. sinistrin were performed in a canine model. Animals were treated with one-sided renal wrapping (RW) followed by renal artery occlusion (RO). Biomarker and remote hemodynamic measurements were performed. Plasma sinistrin in comparison to transcutaneous derived GFR data were determined during healthy conditions, after RW and RW+RO.

RESULTS

RW alone did not led to any significant changes in renal function, neither with PS-GFR nor TD-GFR. Additional RO showed a rise in blood pressure (+68.0mmHg), plasma urea (+28.8mmol/l), creatinine (+224,4μmol/l) and symmetric dimethylarginine (SDMA™; +12.6μg/dl). Plasma sinistrin derived data confirmed the expected drop (-44.7%, p<0.0001) in GFR. The calculated transcutaneous determined Fluorescein Isothiocyanate (FITC)-sinistrin GFR showed no differences to plasma sinistrin GFR at all times. Both methods were equaly sensitive to diagnose renal dysfunction in the affected animals.

DISCUSSION

Renal function assessment using TD-GFR is a valid method to improve preclinical drug discovery and development. Furthermore, TD-GFR method offers advantages in terms of reduced need for blood sampling and thus decreasing animal burden compared to standard procedures.

Prolonged Delayed Graft Function Due to an Extensive Renal Graft Subcapsular Hematoma: Is Conservative Management Justified?

A 62-year-old male patient with diabetes underwent deceased-donor kidney transplant at our transplant unit. At reperfusion, a small and clinically not significant subcapsular hematoma was noted. The patient's postoperative course was characterized by delayed graft function since the beginning but was further complicated on postoperative day 6 by evidence (shown at daily Doppler ultrasonography) of a wide increase of the hematoma. The hematoma, which was just visible before, was now leading to graft compression because it covered up to two-thirds of the cortical surface. The patient showed no hemo-dynamic instability and showed no significant drop in hemoglobin values. Capsulotomy was not performed because it was deemed too risky. The patient was given strict follow-up with Doppler ultrasonography and high-resolution imaging techniques (magnetic resonance imaging and computed tomography scan). In the following days, spontaneous resolution of the hematoma and progressive improvement of Doppler findings were observed, which preceded full recovery of graft function. Conservative management, in hemodynamically stable patients, seems to be a valid approach of this condition. By avoiding surgery or other interventional procedures, a conservative approach allows reduced risk of further complications. Strict monitoring with Doppler ultrasonography is a valid tool for follow-up, along with high-resolution imaging techniques such as magnetic resonance imaging and computed tomography to confirm diagnosis.

Role of the Immune System in Hypertension

High blood pressure is present in more than one billion adults worldwide and is the most important modifiable risk factor of death resulting from cardiovascular disease. While many factors contribute to the pathogenesis of hypertension, a role of the immune system has been firmly established by a large number of investigations from many laboratories around the world. Immunosuppressive drugs and inhibition of individual cytokines prevent or ameliorate experimental hypertension, and studies in genetically-modified mouse strains have demonstrated that lymphocytes are necessary participants in the development of hypertension and in hypertensive organ injury. Furthermore, immune reactivity may be the driving force of hypertension in autoimmune diseases. Infiltration of immune cells, oxidative stress, and stimulation of the intrarenal angiotensin system are induced by activation of the innate and adaptive immunity. High blood pressure results from the combined effects of inflammation-induced impairment in the pressure natriuresis relationship, dysfunctional vascular relaxation, and overactivity of the sympathetic nervous system. Imbalances between proinflammatory effector responses and anti-inflammatory responses of regulatory T cells to a large extent determine the severity of inflammation. Experimental and human studies have uncovered autoantigens (isoketal-modified proteins and heat shock protein 70) of potential clinical relevance. Further investigations on the immune reactivity in hypertension may result in the identification of new strategies for the treatment of the disease.

Left Atrial Remodeling and Atrioventricular Coupling in a Canine Model of Early Heart Failure With Preserved Ejection Fraction

BACKGROUND

Left atrial (LA) compliance and contractility influence left ventricular stroke volume. We hypothesized that diminished LA compliance and contractile function occur early during the development of heart failure with preserved ejection fraction (HFpEF) and impair overall cardiac performance.

METHODS AND RESULTS

Cardiac magnetic resonance imaging, echocardiography, left ventricular and LA pressure-volume studies, and tissue analyses were performed in a model of early HFpEF (elderly dogs, renal wrap-induced hypertension, exogenous aldosterone; n=9) and young control dogs (sham surgery; n=13). Early HFpEF was associated with LA enlargement, cardiomyocyte hypertrophy, and enhanced LA contractile function (median active emptying fraction 16% [95% confidence interval, 13-24]% versus 12 [10-14]%, P=0.008; end-systolic pressure-volume relationship slope 2.4 [1.9-3.2]mm Hg/mL HFpEF versus 1.5 [1.2-2.2]mm Hg/mL controls, P=0.01). However, atrioventricular coupling was impaired and the curvilinear LA end-reservoir pressure-volume relationship was shifted upward/leftward in HFpEF (LA stiffness constant [β_LA] 0.16 [0.11-0.18]mm Hg/mL versus 0.06 [0.04-0.10]mm Hg/mL controls; P=0.002), indicating reduced LA compliance. Impaired atrioventricular coupling and lower LA compliance correlated with lower left ventricular stroke volume. Total fibrosis and titin isoform composition were similar between groups; however, titin was hyperphosphorylated in HFpEF and correlated with β_LA. LA microvascular reactivity was diminished in HFpEF versus controls. LA microvascular density tended to be lower in HFpEF and inversely correlated with β_LA.

CONCLUSIONS

In early-stage hypertensive HFpEF, LA cardiomyocyte hypertrophy, titin hyperphosphorylation, and microvascular dysfunction occur in association with increased systolic and diastolic LA chamber stiffness, impaired atrioventricular coupling, and decreased left ventricular stroke volume. These data indicate that maladaptive LA remodeling occurs early during HFpEF development, supporting a concept of global myocardial remodeling.

Vascular reactivity of rabbit isolated renal and femoral resistance arteries in renal wrap hypertension

In rabbits with cellophane renal wrap hypertension, hindquarter and total vascular resistance changes to pressor and depressor agents are amplified compared to those of normotensive rabbits. The aim of the present study was to evaluate the in vitro pharmacodynamics of hypertensive and normotensive rabbit small artery segments isolated from the renal and hindquarter vascular beds. Using wire myography, the full range (Emax) and sensitivity (EC50) to a range of agonists of segments of renal interlobar (≈ 600 µm i.d.), renal arcuate (≈ 250 µm i.d.) and deep femoral branch (≈ 250 µm i.d.) arteries were assessed under normalised conditions of passive tension. Interlobar arteries from hypertensive rabbits were more sensitive (EC50) than those from normotensive rabbits to noradrenaline (6-fold), methoxamine (3-fold) and angiotensin II (3-fold). Arcuate artery reactivity was largely unaffected by hypertension. Deep femoral arteries from hypertensive rabbits had enhanced sensitivity only to noradrenaline (2-fold) and methoxamine (4-fold). Sensitivity to relaxation by acetylcholine was unaffected by hypertension in all arteries. Deep femoral arteries from hypertensive rabbits were more sensitive to sodium nitroprusside than normotensive counterparts. Adenosine caused little relaxation in renal arteries, but full relaxation in deep femoral arteries, unaltered by hypertension. This study found substantial heterogeneity in the pharmacodynamic profile of vessels isolated from different vascular beds and between arterial segments within the kidney. These profiles were differentially affected by hypertension suggesting that hypertension per se is not a resultant of general vascular dysfunction.

Acute renal failure and arterial hypertension due to subcapsular haematoma: is percutaneous drainage a feasible treatment?

Percutaneous drainage proved to be successful in managing a renal subcapsular haematoma that was causing acute renal failure and hypertension in a 74-year-old woman. The patient presented with oliguria, nausea and malaise 2 days after a ureteronephroscopic procedure with biopsies of a suspected urothelial neoplasm in the right renal pelvis. The left kidney had recently been removed due to renal cell carcinoma. At admission, the patient's blood pressure and plasma creatinine levels were massively elevated. Ultrasonography revealed a moderate right-sided renal subcapsular haematoma. When the patient did not respond to antihypertensive treatment, Page kidney was suspected. A pigtail catheter was placed in the haematoma and, shortly after drainage, the diuresis resumed and plasma creatinine together with blood pressure decreased. This condition had previously been managed by open surgery, but recent case reports have described successful management by laparoscopy-assisted and radiology-assisted drainage, as described in this case report.

Ambulatory blood pressure and tubulointerstitial injury in patients with IgA nephropathy

Background

Few studies have been conducted to assess the ambulatory blood pressure (ABP) in IgA nephropathy (IgAN) patients. This study aimed to determine the relationships between ABP and renal histopathological findings assessed using the Oxford classification (OC) and the Japanese classification (JC), which have recently established histopathological criteria for IgAN.

Methods

This cross-sectional study included biopsy-diagnosed IgAN patients, in whom both a renal biopsy and ABP measurement were performed. The histopathological findings were assessed using the OC and the JC and were analyzed in relation to the ABP.

Results

A total of 111 IgAN patients were included. The score of interstitial fibrosis and tubular atrophy (T score) using the OC was a significantly associated factor with both the daytime and nighttime ABP values. In contrast, the other histopathological scores, including mesangial hypercellularity, endocapillary hypercellularity and segmental glomerulosclerosis, did not show significant associations with the ABP. The histological grade (H-grade) using the JC, which was based on the sum of injured glomeruli, was associated with the daytime ABP, but not with the nighttime ABP. The associations between the T score using the OC (%) and the daytime and nighttime ABP values were independent of age, gender, renal function, proteinuria and the use of antihypertensive medications, whereas the H-grade using the JC (%) did not show significant associations after adjusting for these clinical parameters.

Conclusions

These results suggest that the T score using the OC is the most relevant renal histopathological parameter associated with abnormalities of circadian blood pressure in IgAN patients.

Laparoscopic treatment of Page kidney: a report of two cases and review of the literature

Page kidney is defined as the external compression of the kidney, typically by a subcapsular hematoma, that leads to hypertension due to hypoperfusion and ischemia. The treatment options include medical anti-hypertensive treatment, percutaneous drainage, surgical decortication and nephrectomy. Laparoscopic decortication of Page kidney is a newly defined minimally invasive management technique. We describe 2 cases of Page kidney that failed to improve with percutaneous drainage but were successfully treated with the laparoscopic approach.

The immunological basis of hypertension

A large number of investigations have demonstrated the participation of the immune system in the pathogenesis of hypertension. Studies focusing on macrophages and Toll-like receptors have documented involvement of the innate immunity. The requirements of antigen presentation and co-stimulation, the critical importance of T cell-driven inflammation, and the demonstration, in specific conditions, of agonistic antibodies directed to angiotensin II type 1 receptors and adrenergic receptors support the role of acquired immunity. Experimental findings support the concept that the balance between T cell-induced inflammation and T cell suppressor responses is critical for the regulation of blood pressure levels. Expression of neoantigens in response to inflammation, as well as surfacing of intracellular immunogenic proteins, such as heat shock proteins, could be responsible for autoimmune reactivity in the kidney, arteries, and central nervous system. Persisting, low-grade inflammation in these target organs may lead to impaired pressure natriuresis, an increase in sympathetic activity, and vascular endothelial dysfunction that may be the cause of chronic elevation of blood pressure in essential hypertension.

Renal histopathological findings in relation to ambulatory blood pressure in chronic kidney disease patients

Recent studies have demonstrated that ambulatory blood pressure monitoring is useful for predicting the long-term renal prognosis and future cardiovascular events in chronic kidney disease patients. Currently, however, information is limited regarding the relationships between individual renal histopathological findings and abnormalities in ambulatory blood pressure. This retrospective cross-sectional study included a total of 138 patients, in whom both renal biopsies and ambulatory blood pressure monitoring were performed during the same admission period. Renal histopathological findings, including global glomerulosclerosis, interstitial fibrosis/tubular atrophy and the presence of arterial lesions and arteriole lesions, were scored and analyzed in relation to the ambulatory blood pressure values. Among these histopathological characteristics, only the severity of interstitial fibrosis/tubular atrophy exhibited a significant association with an increased mean value of daytime and nighttime blood pressure. However, the remaining histopathological features showed only trends or weak relationships with these values. In addition, a moderately advanced grade of interstitial fibrosis/tubular atrophy was found to be significantly associated with both daytime and nighttime hypertension, independent of the kidney function, overt proteinuria and the use of antihypertensive medications, according to multivariate analyses. Furthermore, the night-to-day ratio of the mean blood pressure displayed a significant increasing trend according to the grade of interstitial fibrosis/tubular atrophy. These results suggest that interstitial fibrosis/tubular atrophy is the most relevant renal histopathological parameter associated with abnormalities in ambulatory blood pressure, including nocturnal hypertension, in this population.

Update on heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFPEF) is the most common form of heart failure (HF) in older adults, and is increasing in prevalence as the population ages. Morbidity and long-term mortality in HFPEF are substantial and can be similar to HF with reduced ejection fraction (HFREF), yet HFPEF therapy remains empirical and treatment guidelines are based primarily on expert consensus. Neurohormonal blockade has revolutionized the management of HFREF, but trials in HFPEF based on this strategy have been disappointing to date. However, many recent studies have increased knowledge about HFPEF. The concept of HFPEF has evolved from a 'cardio-centric' model to a syndrome that may involve multiple cardiovascular and non-cardiovascular mechanisms. Emerging data highlight the importance of non-pharmacological management strategies and assessment of non-cardiovascular comorbidities. Animal models, epidemiological cohorts, and small human studies suggest that oxidative stress and inflammation contribute to HFPEF, potentially leading to development of new therapeutic targets.

Impaired pressure natriuresis is associated with interstitial inflammation in salt-sensitive hypertension

PURPOSE OF REVIEW

Impairment of the pressure natriuresis relationship is a central event in the pathogenesis of hypertension. Renal tubulointerstitial inflammation results in salt-sensitive hypertension and, until recently, the changes in pressure natriuresis induced by renal inflammation received little attention.

RECENT FINDINGS

Oxidative stress and increased intrarenal angiotensin II activity, in association with rarefaction and loss of peritubular vascular network, may be involved in the inflammation-induced blunting of the natriuresis resulting from increments in renal perfusion pressure.

SUMMARY

Here, we review the mechanisms for the impairment in pressure natriuresis resulting from renal tubulointerstitial inflammation in reference to the normal physiologic mechanisms involved in this response.

Impaired pressure natriuresis resulting in salt-sensitive hypertension is caused by tubulointerstitial immune cell infiltration in the kidney

Immune cell infiltration of the kidney is a constant feature in salt-sensitive hypertension (SSHTN). We evaluated the relationship between the renal inflammation and pressure natriuresis in the model of SSHTN that results from transient oral administration of N(ω)-nitro-L-arginine methyl ester (L-NAME). Pressure natriuresis was determined in Wistar rats that received 4 wk of a high-salt (4% NaCl) diet, starting 1 wk after stopping L-NAME, which was administered alone (SSHTN group, n = 17) or in association with mycophenolate mofetil (MMF; MMF group, n = 15). The administration of MMF in association with L-NAME is known to prevent the subsequent development of SSHTN. Control groups received a high (n = 12)- and normal (0.4%)-salt diet (n = 20). Rats with SSHTN had increased expression of inflammatory cytokines and oxidative stress. The severity of hypertension correlated directly (P < 0.0001) with the number of tubulointerstitial immune cells and angiotensin II-expressing cells. Pressure natriuresis was studied at renal arterial pressures (RAPs) of 90, 110, 130, and 150 mmHg. Glomerular filtration rate was similar and stable in all groups, and renal blood flow was decreased in the SSHTN group. Significantly decreased natriuresis (P < 0.05) was found in the SSHTN group at RAPs of 130 and 150 mmHg, and there was an inverse correlation (P < 0.01) between the urinary sodium excretion and the number of tubulointerstitial inflammatory cells (lymphocytes and macrophages) and cells expressing angiotensin II. We conclude that tubulointerstitial inflammation plays a key role in the impairment of pressure natriuresis that results in salt-dependent hypertension in this experimental model.

The role of T cells in the pathogenesis of primary hypertension

Accumulating evidence indicates that T cells play an important role in the pathogenesis of hypertension. Here we review the investigations that have shown that T cells are infiltrating the kidney in hypertension. Interstitial accumulation of immune cells is associated with increments in oxidative stress and renal angiotensin II activity that result in the impairment in pressure natriuresis. The severity of salt-sensitive hypertension is directly correlated with the intensity of immune cell infiltration in the kidney. Reducing the renal infiltration of T cells prevents or ameliorates hypertension and the induction of tubulointerstitial inflammation results in salt-sensitive hypertension. The potential participation of autoimmune mechanisms in the renal infiltration of immune competent cells is discussed.

Overexpression of HGF transgene attenuates renal inflammatory mediators, Na(+)-ATPase activity and hypertension in spontaneously hypertensive rats

Renal inflammation and oxidative stress are constantly present in experimental hypertension. Since the spontaneously hypertensive rat (SHR) has reduced levels of hepatocyte growth factor (HGF), which suppresses the activation of the proinflammatory nuclear transcription factor kappa B (NF-κB), we speculated that HGF deficiency could play a key role in the pathogenesis of hypertension in the SHR. To test this hypothesis we increased HGF in the SHR by HGF gene delivery. We found that kidneys of 15-week-old SHR had an important reduction in HGF mRNA and protein expression. Adult SHRs were randomly assigned to receive weekly hydrodynamic injection (1mg/kg) of a naked plasmid containing human HGF (hHGF) gene associated with a cytomegalovirus promoter (pCMV-HGF) or empty vector (pcDNA3.1) during 6weeks. WKY rats treated with pcDNA3.1 and pCMV-HGF served as controls. The kidneys in the hypertensive SHR untreated and treated with the empty vector had increased NF-κB activation, elevated mRNA and protein expression of RANTES, MCP-1 and IL-6 and increased oxidative stress. Activity of Na(+)-ATPase was increased while activity of Na(+), K(+)-ATPase was normal. hHGF gene therapy normalized renal NF-κB activity, proinflammatory cytokines, antioxidant status (GSH, SOD and CAT), Na(+)-ATPase activity, reduced renal injury and ameliorated hypertension. Our results suggest that reduction in HGF production plays a major role in the pathogenesis of hypertension in the SHR and increasing HGF is a potential therapeutic target in the treatment of hypertension.

Renal inflammation, autoimmunity and salt-sensitive hypertension

1. The present article reviews the role of immune-competent cells infiltrating the kidney and their association with oxidative stress and renal angiotensin activity in the development of salt-sensitive hypertension. 2. We discuss changes in the pressure-natriuresis relationship resulting from renal inflammation and its improvement resulting from immunosuppressive treatment. 3. The potential role of T-cell-driven reactivity in sustaining the renal inflammation is examined in the light of accumulating evidence of autoimmune mechanisms in experimental and clinical hypertension.

Immunosuppression with mycophenolate mofetil attenuates the development of hypertension and albuminuria in deoxycorticosterone acetate-salt hypertensive rats

1. The interplay between the immune and renin-angiotensin systems is emerging as a crucial factor in the development and progression of hypertension. The aim of the present study was to determine the involvement of immune cells in the hypertension and renal injury produced by a non-angiotensin II-dependent form of hypertension, namely deoxycorticosterone acetate (DOCA)-salt-induced hypertension, in rats. 2. Male Sprague-Dawley rats underwent uninephrectomy and received either a sustained-release pellet of DOCA s.c. and 0.9% NaCl (saline) to drink for 21 days or a placebo pellet and water to drink for 21 days. Additional groups of DOCA-salt- and placebo-treated rats were treated concurrently with the immune suppressant mycophenolate mofetil (MMF; 30 mg/kg per day). Rats were placed in metabolic cages for 24 h urine collection prior to and at weekly intervals during the 21 day experimental period. 3. Mycophenolate mofetil significantly attenuated the development of hypertension in DOCA-salt rats compared with untreated DOCA-salt hypertensive rats (mean arterial pressure by telemetry on Day 18,146 ± 7 vs 180 ± 3 mmHg, respectively; P < 0.001), as well as proteinuria (87 ± 27 vs 305 ± 63 mg/day, respectively, on Day 21) and albuminuria (51 ± 15 vs 247 ± 73 mg/day, respectively, on Day 21). Creatinine clearance was better preserved in MMF-treated DOCA-salt rats compared with untreated DOCA-salt rats (0.74 ± 0.07 vs 0.49 ± 0.09 mL/min, respectively; P < 0.05), but was still significantly reduced compared with that in the placebo group (1.15 ± 0.12 mL/min; P < 0.05). Finally, MMF treatment significantly attenuated the DOCA-salt-induced rise in renal cortical T-lymphocyte and macrophage infiltration (P < 0.05). 4. These data indicate that immune cells play a deleterious role in both the hypertension and renal injury associated with DOCA-salt hypertension.

An unusual presentation of a Page kidney 24 days after transplantation: case report

The Page kidney phenomenon is a well recognized entity where an extrinsically compressed kidney results in hypertension and loss of function. This compression is usually caused by a subcapsular hematoma secondary to blunt abdominal trauma or an invasive procedure such as a renal biopsy. We describe an unusual case involving the spontaneous development of a Page kidney 24 days after renal transplantation without any history of preceding trauma. The subcapsular hematoma was detected by a computerized tomographic scan performed as part of the work-up for acute allograft dysfunction. Prompt recognition and early intervention are essential if renal function is to be restored before irreversible damage occurs.

Prenatal exposure to inflammation induced by zymosan results in activation of intrarenal renin-angiotensin system in adult offspring rats

Prenatal exposure to inflammation produces offspring that are hypertensive in adulthood. The present study was to explore the role of intrarenal renin-angiotensin (Ang) system in the development of hypertension programmed by prenatal exposure to zymosan. Pregnant rats were randomly divided into control group and zymosan group (n = 6). Rats in these two groups were administered intraperitoneally with 0.5 ml vehicle and 2.37 mg/kg zymosan, respectively, on the eighth, tenth, and 12th day during gestation. The results showed the glomerular number and creatinine clearance rate decreased significantly in offspring of zymosan-treated rats. The renal cortex renin mRNA expression, Ang II-positive cells in renal cortex, and Ang II expression in renal medulla increased significantly in offspring of zymosan-treated rats at 7, 16, and 25 weeks of age. The plasma renin activity and Ang II concentration were unchanged. In conclusion, prenatal exposure to zymosan resulted in the activation of intrarenal renin-Ang system in adult offspring rats.

Doxorubicin-induced ovarian toxicity

BACKGROUND

Young cancer patients may occasionally face infertility and premature gonadal failure. Apart from its direct effect on follicles and oocytes, chemotherapy may induce ovarian toxicity via an impact on the entire ovary. The role of doxorubicin in potential ovarian failure remains obscure. Our intention was to elucidate doxorubicin-related toxicity within ovaries.

METHODS

Female mice were injected intraperitoneally with 7.5 or 10 mg/kg doxorubicin and their ovaries were visualized in vivo by high resolution MRI, one day and one month following treatment. Ovaries of other treated mice were excised and weighed at the same post-treatment intervals. Ovarian histological sections were stained for TUNEL or active caspase-3 and follicles were counted and categorized. Ovulation rates were evaluated in superovulated female mice treated with doxorubicin.

RESULTS

A single injection of doxorubicin resulted in a major reduction in both ovarian size and weight that lasted even one month post treatment. A dramatic reduction in ovulation rate was observed one week after treatment, followed by a partial recovery at one month. Histological examination revealed positive staining of TUNEL and active caspase-3. We observed a significant reduction in the population of secondary and primordial follicles one month following treatment.

CONCLUSIONS

Our results may imply a mechanism of chemotherapy-induced ovarian toxicity, manifested by reduced ovulation and accompanied by a reduction in ovarian size, caused probably by an acute insult to the ovary.

[Traumatic subcapsular renal lymphocele: an unusual form of Page kidney]

A 17-year-old boy who received a kick on his right back during the training of karate complained of gross hematuria. Computed tomography revealed slight bleeding at the lower pole of right kidney. His general condition was stable and the gross hematuria was improved immediately. After one month, CT revealed a large right subcapsular renal fluid accumulation with parenchymal compression and his blood pressure became elevated. We diagnosed as Page kidney associated with subcupsular renal lymphocele after trauma. Percutaneous drainage and laparoscopic cyst fenestration were performed. After the procedures, the fluid accumulation was recurred and the blood pressure became elevated again. We disclosed a case of Page kidney associated with subcupsular renal lymphocele and propose that careful management should be needed in a patient like our case.

Page kidney as a rare cause of hypertension: case report and review of the literature

Page kidney occurs by extrinsic compression of the renal parenchyma from a hematoma or a mass, leading to activation of the renin-angiotensin-aldosterone system and resulting in systemic hypertension. There have been about 100 cases of Page phenomenon reported in the literature. A review of cases published prior to 1991 revealed that football and nonsports-related trauma were the most common causes of Page kidney. Thereafter, 28 cases have been reported in the literature, including our case report presented here. These recent cases show that the etiology of Page kidney has shifted, perhaps because of the procedure-oriented current practice of medicine and the increased frequency of kidney transplant biopsies. In addition, management options have evolved, given the more frequent use of medications that block the renin-angiotensin-aldosterone system and the availability of less invasive procedures. Page kidney should be considered in the differential diagnosis of secondary hypertension.

Pathogenesis of essential hypertension: historical paradigms and modern insights

Since its first identification in the late 1800s, a variety of etiologies for essential hypertension have been proposed. In this paper we review the primary proposed hypotheses in the context of both the time in which they were proposed as well as the subsequent studies performed over the years. From these various insights, we propose a current paradigm to explain the renal mechanisms underlying the hypertension epidemic today. Specifically, we propose that hypertension is initiated by agents that cause systemic and intrarenal vasoconstriction. Over time intrarenal injury develops with microvascular disease, interstitial T cell and macrophage recruitment with the induction of an autoimmune response, with local angiotensin II formation and oxidant generation. These changes maintain intrarenal vasoconstriction and hypoxia with a change in local vasoconstrictor-vasodilator balance favoring sodium retention. Both genetic and congenital (nephron number) mechanisms have profound influence on this pathway. As blood pressure rises, renal ischemia is ameliorated and sodium balance restored completely (in salt-resistant) or partially (in salt-sensitive) hypertension, but at the expense of a rightward shift in the pressure natriuresis curve and persistent hypertension.

Mineralocorticoid Signaling in Transition to Heart Failure With Normal Ejection Fraction

Heart failure with normal ejection fraction occurs in elderly patients with hypertensive heart disease. We hypothesized that, in such patients, mineralocorticoid receptor activation accelerates the types of ventricular and vascular remodeling and dysfunction believed important in the transition to heart failure. We tested this hypothesis by administering deoxycorticosterone acetate (DOCA) without salt loading or nephrectomy to elderly dogs with experimental hypertension. Elderly dogs were made hypertensive by renal wrapping. After 5 weeks, dogs were randomly assigned to DOCA (1 mg/kg per day IM; old hypertensive [OH]+DOCA; n=11) or not (OH; n=11) for 3 weeks. At week 8, conscious echocardiography and hemodynamic assessment under anesthesia were performed. DOCA resulted in further increases in conscious blood pressure ( P <0.05) without increases in cardiac output or diastolic volume. In the conscious state, effective arterial elastance ( P <0.05) and systemic vascular resistance ( P =0.06) were increased, and systemic arterial compliance ( P <0.05) was decreased in OH+DOCA animals. After anesthesia, instrumentation, and autonomic blockade, blood pressure was lower, whereas left ventricular (LV) systolic elastance, LV diastolic stiffness, and ex vivo myofiber diastolic stiffness were increased in OH+DOCA animals. LV collagen was increased in OH+DOCA animals ( P <0.05 for all), but LV mass, LV brain natriuretic peptide, and titin isoform profiles were not. Neither aortic stiffness nor aortic structure was altered in OH+DOCA animals. These findings suggest that age and hypertensive heart disease enhance sensitivity to exogenous mineralocorticoid administration and that mineralocorticoid receptor activation could contribute to the transition to heart failure in elderly persons by promoting increases in LV diastolic and systolic stiffness.

Mycophenolate mofetil treatment improves hypertension in patients with psoriasis and rheumatoid arthritis

Evidence that was obtained in several experimental models and in strains of hypertensive rats indicates that infiltration of inflammatory cells and oxidative stress in the kidney play a role in the induction and maintenance of hypertension. Similar evidence is lacking in human hypertension, at least in part, because immunosuppressive treatment is unjustified in patients with hypertension. For addressing this issue, patients who were prescribed by their private physicians mycophenolate mofetil (MMF) for the treatment of psoriasis or rheumatoid arthritis and had, in addition, grade I essential hypertension and normal renal function were studied. Eight patients were studied before MMF was started, during MMF treatment, and 1 mo after MMF treatment had been discontinued. Other treatments and diet were unchanged in the three phases of the study. MMF therapy was associated with a significant reduction in systolic, diastolic, and mean BP. Urinary excretion of TNF-alpha was reduced progressively by MMF treatment and increased after MMF was discontinued. Reduction of urinary malondialdehyde, TNF-alpha, and RANTES excretion during MMF administration did not reach statistical significance but had a direct positive correlation with the BP levels. These data are consistent with the hypothesis that renal immune cell infiltration and oxidative stress play a role in human hypertension.

The intrarenal renin-angiotensin system: from physiology to the pathobiology of hypertension and kidney disease

In recent years, the focus of interest on the role of the renin-angiotensin system (RAS) in the pathophysiology of hypertension and organ injury has changed to a major emphasis on the role of the local RAS in specific tissues. In the kidney, all of the RAS components are present and intrarenal angiotensin II (Ang II) is formed by independent multiple mechanisms. Proximal tubular angiotensinogen, collecting duct renin, and tubular angiotensin II type 1 (AT1) receptors are positively augmented by intrarenal Ang II. In addition to the classic RAS pathways, prorenin receptors and chymase are also involved in local Ang II formation in the kidney. Moreover, circulating Ang II is actively internalized into proximal tubular cells by AT1 receptor-dependent mechanisms. Consequently, Ang II is compartmentalized in the renal interstitial fluid and the proximal tubular compartments with much higher concentrations than those existing in the circulation. Recent evidence has also revealed that inappropriate activation of the intrarenal RAS is an important contributor to the pathogenesis of hypertension and renal injury. Thus, it is necessary to understand the mechanisms responsible for independent regulation of the intrarenal RAS. In this review, we will briefly summarize our current understanding of independent regulation of the intrarenal RAS and discuss how inappropriate activation of this system contributes to the development and maintenance of hypertension and renal injury. We will also discuss the impact of antihypertensive agents in preventing the progressive increases in the intrarenal RAS during the development of hypertension and renal injury.

Pathophysiological Mechanisms of Salt-Dependent Hypertension

Changes in salt intake are associated in general with corresponding changes in arterial blood pressure. An exaggerated increment in blood pressure driven by a salt load is characteristic of salt-sensitive hypertension, a condition affecting more than two thirds of individuals with essential hypertension who are older than 60 years. In the last decade, significant insight was gained about the role of the kidney in the increment in blood pressure induced by sodium retention. The present review focuses on the pathophysiological characteristics of the blood pressure increase driven by expansion of extracellular fluid and the increment in plasma sodium concentration. In addition, we discuss systemic and renal conditions that result in decreased urinary sodium excretion and were implicated in the development of salt-sensitive hypertension.

Laparoscopic management of bilateral page kidneys

Hyper-reninemic hypertension as a result of renal compression is often referred to as a "Page" kidney. We present a case of a patient with bilateral Page kidneys from subcapsular hematomas as a complication of extracorporeal shock wave lithotripsy. After several attempts at percutaneous and laparoscopic drainage of the fluid collections, she was referred for definitive management with laparoscopic decortication and capsulotomy. Bilateral laparoscopic surgery was performed in a staged fashion, using a novel technique of radial incision inner capsulotomy, with resolution of the patient's hypertension. We report our technique and factors to consider in the management of Page kidney.

Mycophenolate mofetil administration reduces renal inflammation, oxidative stress, and arterial pressure in rats with lead-induced hypertension

Hypertension is a likely consequence of chronic lead exposure in humans, especially in association with reduced renal function and in high risk populations. Numerous studies have demonstrated that oxidative stress plays an important role in the pathogenesis of experimental lead-induced hypertension and we have shown recently that tubulointerstitial immune cell infiltration is a feature of chronic low-dose lead exposure. Since oxidative stress, renal inflammation, and angiotensin activity are closely linked characteristics in experimental models of hypertension, we decided to investigate whether lead-induced hypertension would be ameliorated by suppressing renal inflammation with the immunosuppressive drug mycophenolate mofetil (MMF). We studied rats exposed for 14 wk to lead acetate (100 ppm in the drinking water) that, in addition, received either MMF, 20 mg.kg(-1).day(-1) by gastric gavage (Pb.MMF group, n = 12) or vehicle (Pb group, n = 12). Control rats received MMF alone (n = 5) or neither lead nor MMF (n = 6). All rats were killed at the end of the experiment. Low-dose lead exposure resulted in mild to moderate tubular cell damage and a progressive increment in blood pressure, oxidative stress, interstitial accumulation of lymphocytes and macrophages, NF-kappaB activation, and increased renal angiotensin II level. The administration of MMF suppressed the tubulointerstitial accumulation of lymphocytes and macrophages and prevented the hypertension, oxidative stress, and NF-kappaB activation and reduced the heightened renal angiotensin content associated with chronic lead exposure. We conclude that interstitial inflammation plays an important role in lead-induced hypertension.

Renal angiotensin II concentration and interstitial infiltration of immune cells are correlated with blood pressure levels in salt-sensitive hypertension

Renal immune cell infiltration and cells expressing angiotensin II (AII) in tubulointerstitial areas of the kidney are features of experimental models of salt-sensitive hypertension (SSHTN). A high-salt intake tends to suppress circulating AII levels, but intrarenal concentrations of AII have not been investigated in SSHTN. This study explored the relationship between these features to gain insight into the pathophysiology of SSHTN. Plasma angiotensin II (AII) and renal interstitial AII (microdialysis technique) and the infiltration of macrophages, lymphocytes, and AII-positive cells were determined in SSHTN induced by 5 wk of a high-salt diet (HSD) after short-term infusion of AII in rats with (n = 10) and without (n = 11) treatment with mycophenolate mofetil (MMF) and in control rats fed a high- (n = 7) and normal (n = 11) salt diet. As in previous studies, MMF did not affect AII-associated hypertension but reduced the interstitial inflammation and the SSHTN in the post-AII-period. During the HSD period, the AII group untreated with MMF had mean +/- SD) low plasma (2.4 +/- 1.4 pg/ml) and high interstitial AII concentration (1,310 +/- 208 pg/ml); MMF treatment resulted in a significantly lower interstitial AII (454 +/- 128 pg/ml). Renal AII concentration and the number of tubulointerstitial AII-positive cells were correlated. Blood pressure correlated positively with interstitial AII and negatively with plasma AII, thus giving compelling evidence of the paramount role of the AII within the kidney in the AII-induced model of salt-driven hypertension.

Mechanisms of disease: oxidative stress and inflammation in the pathogenesis of hypertension

Animal studies have shown that oxidative stress and renal tubulointerstitial inflammation are associated with, and have major roles in, the pathogenesis of hypertension. This view is supported by the observations that alleviation of oxidative stress and renal tubulointerstitial inflammation reduce arterial pressure in animal models. Conversely, hypertension has been shown to cause oxidative stress and inflammation in renal and cardiovascular tissues in experimental animals. Taken together, these observations indicate that oxidative stress, inflammation and arterial hypertension participate in a self-perpetuating cycle which, if not interrupted, can lead to progressive cardiovascular disease and renal complications. These events usually occur in an insidious and asymptomatic manner over an extended period following the onset of hypertension. Severe target organ injury can, however, occasionally occur precipitously in the course of malignant or accelerated hypertension. Given the high degree of heterogeneity of hypertensive disorders, the factor(s) initiating the vicious cycle described vary considerably in different forms of hypertension. For instance, oxidative stress in the kidney and vascular tissue is the primary mediator in the pathogenesis of angiotensin-induced, and perhaps lead-induced, hypertension. By contrast, increased arterial pressure is probably the initiating trigger in salt-sensitive hypertension. Although the initiating factor might vary between hypertensive disorders, according to the proposed model, the three components of the cycle eventually coalesce in all forms of hypertension.