Prevention of renal damage by angiotensin II blockade, accompanied by increased renal hepatocyte growth factor in experimental hypertensive rats

Association of metabolic syndrome and its components with the risk of urologic cancers: a prospective cohort study

OBJECTIVE

To investigate the association between metabolic syndrome (MetS) and its components and the risk of developing urologic cancers.

METHODS

This study included 101,510 observation subjects from May 2006 to December 2007. The subjects received questionnaires and were subjected to clinical and laboratory examinations to collect data on baseline population characteristics, waist circumference (WC), blood pressure (BP), blood glucose, blood lipids, lifestyle, and past disease history. Finally, follow-up was conducted from the date of recruitment to December 31, 2019. Cox proportional hazards modelling was applied to analyze the association between MetS and its components and the risk of developing urologic cancers.

RESULTS

A total of 97,975 observation subjects met the inclusion criteria. The cumulative follow-up period included 1,209,178.65 person-years, and the median follow-up time was 13.03 years. During the follow-up period, 485 cases of urologic cancers (165 cases of kidney cancer, 134 cases of prostate cancer, 158 cases of bladder cancer, and 28 cases of other urologic cancers) were diagnosed. The log-rank test results for the cumulative incidences of urologic cancer, kidney cancer, and prostate cancer indicated significant (P < 0.01) differences between the MetS and non-MetS groups (0.70% vs. 0.48%, 0.27% vs. 0.15%, and 0.22% vs. 0.13%, respectively). Compared to the non-MetS group, the risk of developing urologic [HR (95% CI) = 1.29 (1.08-1.55)], kidney [HR (95% CI) = 1.74 (1.28-2.37)], and prostate [HR (95% CI) = 1.47 (1.04-2.07)] cancers was significantly higher in the MetS group. In the MetS group, elevated BP increased the risk of developing of urologic cancer [HRs (95% CI) = 1.35 (1.10-1.66)] and kidney cancer [HR (95% CI) = 1.74 (1.21-2.51)], while central obesity increased the risk of developing prostate cancer [HR (95% CI) = 1.68 (1.18-2.40)].

CONCLUSIONS

MetS increased the risk of developing urologic, kidney, and prostate cancers but had no association with the development of bladder cancer.

Association of metabolic syndrome and its components with the risk of kidney cancer: A cohort-based case-control study

BACKGROUND

Metabolic syndrome increases the risk of developing several types of cancer in humans; however, its effect on the development of kidney cancer is not uniform.

OBJECTIVE

To investigate the association between metabolic syndrome (MetS) and its components and the risk of developing kidney cancer.

METHODS

We conducted a cohort-based case-control study. The case group included 217 patients with new kidney cancer in the Kailuan cohort. A total of 868 subjects who were matched for age and sex with those in the case group age (± 1 year) at 1:4 as the control group were selected from baseline survey participants without malignant tumours at the same time as the case group. Biennial baseline survey data of the cases and controls were collected, and the baseline data nearest to the onset time of cases were used for statistical analyses. Logistic proportional risk regression models were used to analyse the association between MetS and its components and the risk of developing kidney cancer.

RESULTS

The proportion of MetS patients in the case group was significantly higher than that in the control group (P< 0.01). The risk of developing kidney cancer was significantly higher in the MetS group than in the non-MetS group [odds ratio (OR) (95% confidence interval, CI) = 1.63 (1.20-2.21)], and the risk of kidney cancer increased as the number of MetS components increased compared with subjects without any MetS components (p𝑡𝑟𝑒𝑛𝑑< 0.01). Elevated blood pressure and low high-density lipoprotein cholesterol levels were associated with the risk of kidney cancer [OR (95% CI) = 1.49 (1.02-2.17) and 1.55 (1.13-2.13), respectively].

CONCLUSION

Our findings suggest that the risk of developing kidney cancer is correlated with MetS.

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.

Immune and inflammatory role in renal disease

Chronic and acute renal diseases, irrespective of the initiating cause, have inflammation and immune system activation as a common underlying mechanism. The purpose of this review is to provide a broad overview of immune cells and inflammatory proteins that contribute to the pathogenesis of renal disease, and to discuss some of the physiological changes that occur in the kidney as a result of immune system activation. An overview of common forms of acute and chronic renal disease is provided, followed by a discussion of common therapies that have anti-inflammatory or immunosuppressive effects in the treatment of renal disease.

Early life stress induces renal dysfunction in adult male rats but not female rats

Maternal separation (MatSep) is a model of behavioral stress during early life. We reported that MatSep exacerbates ANG II-induced hypertension in adult male rats. The aims of this study were to determine whether exposure to MatSep in female rats sensitizes blood pressure to ANG II infusion similar to male MatSep rats and to elucidate renal mechanisms involved in the response in MatSep rats. Wistar Kyoto (WKY) pups were exposed to MatSep 3 h/day from days 2 to 14, while control rats remained with their mothers. ANG II-induced mean arterial pressure (MAP; telemetry) was enhanced in female MatSep rats compared with control female rats but delayed compared with male MatSep rats. Creatinine clearance (Ccr) was reduced in male MatSep rats compared with control rats at baseline and after ANG II infusion. ANG II infusion significantly increased T cells in the renal cortex and greater histological damage in the interstitial arteries of male MatSep rats compared with control male rats. Plasma testosterone was greater and estradiol was lower in male MatSep rats compared with control rats with ANG II infusion. ANG II infusion failed to increase blood pressure in orchidectomized male MatSep and control rats. Female MatSep and control rats had similar Ccr, histological renal analysis, and sex hormones at baseline and after ANG II infusion. These data indicate that during ANG II-induced hypertension, MatSep sensitizes the renal phenotype in male but not female rats.

Treatment with valsartan stimulates endothelial progenitor cells and renal label-retaining cells in hypertensive rats

OBJECTIVE

The pathogenesis of hypertension is dependent on tissue angiotensin (Ang) II, which induces cardiovascular and renal remodeling. The presence of label-retaining cells (LRCs) as renal stem cells has been reported in nephrotubulus. We examined effects of treatment with valsartan on endothelial progenitor cells (EPCs) and renal LRCs in stroke-prone spontaneously hypertensive rats (SHR-SP).

METHODS

SHR-SP were salt-loaded and treated with hydralazine or valsartan. Peripheral blood mononuclear cells (MNCs) were cultured to assess EPC colony formation and migration. LRCs were labeled for 1 week with bromodeoxyuridine (BrdU) and were detected after a 2-week chase period. We measured expression of c-kit and Pax-2 mRNAs in renal medulla.

RESULTS

Colony formation and migration of EPCs were suppressed in salt-loaded SHR-SP. Treatment with valsartan markedly stimulated these EPC functions. There was no difference in the number of renal LRCs in normotensive Wistar-Kyoto rats and SHR-SP. Treatment with valsartan significantly improved renal tubular degeneration and increased the number of LRCs in renal medulla from salt-loaded SHR-SP. Treatment with valsartan significantly increased expression of c-kit and Pax-2 mRNAs in renal medulla from salt-loaded SHR-SP.

CONCLUSION

These findings suggest that ARBs have cardiovascular and renal protective effects through an antioxidative action that stimulates ECP function and increases the number of the self-repairing renal LRCs.

Hepatocyte growth factor in lung repair and pulmonary fibrosis

Pulmonary remodeling is characterized by the permanent and progressive loss of the normal alveolar architecture, especially the loss of alveolar epithelial and endothelial cells, persistent proliferation of activated fibroblasts, or myofibroblasts, and alteration of extracellular matrix. Hepatocyte growth factor (HGF) is a pleiotropic factor, which induces cellular motility, survival, proliferation, and morphogenesis, depending upon the cell type. In the adult, HGF has been demonstrated to play a critical role in tissue repair, including in the lung. Administration of HGF protein or ectopic expression of HGF has been demonstrated in animal models of pulmonary fibrosis to induce normal tissue repair and to prevent fibrotic remodeling. HGF-induced inhibition of fibrotic remodeling may occur via multiple direct and indirect mechanisms including the induction of cell survival and proliferation of pulmonary epithelial and endothelial cells, and the reduction of myofibroblast accumulation.

Hepatocyte growth factor in lung repair and pulmonary fibrosis

Pulmonary remodeling is characterized by the permanent and progressive loss of the normal alveolar architecture, especially the loss of alveolar epithelial and endothelial cells, persistent proliferation of activated fibroblasts, or myofibroblasts, and alteration of extracellular matrix. Hepatocyte growth factor (HGF) is a pleiotropic factor, which induces cellular motility, survival, proliferation, and morphogenesis, depending upon the cell type. In the adult, HGF has been demonstrated to play a critical role in tissue repair, including in the lung. Administration of HGF protein or ectopic expression of HGF has been demonstrated in animal models of pulmonary fibrosis to induce normal tissue repair and to prevent fibrotic remodeling. HGF-induced inhibition of fibrotic remodeling may occur via multiple direct and indirect mechanisms including the induction of cell survival and proliferation of pulmonary epithelial and endothelial cells, and the reduction of myofibroblast accumulation.

Hepatocyte growth factor gene therapy for hypertension

Hepatocyte growth factor (HGF) has mitogenic, motogenic, and morphogenic biological activities as well as helps in regenerating various tissues. In cardiovascular organs, HGF was reported to have anti-apoptotic, anti-fibrotic, and vasodilating effects. HGF has close relationships with hypertension, arteriosclerosis, and heart failure. HGF enhances renal regeneration and suppresses the progression of hypertension. Intramuscular electroporation of the therapeutic gene is a simple, economic, and low toxic method compared with systemic administration of the purified proteins or peptides. We outline the technique of intramuscular electroporation of HGF gene as a remedy for hypertension.

Inhibition of Rho-kinase attenuates nephrosclerosis and improves survival in salt-loaded spontaneously hypertensive stroke-prone rats

OBJECTIVES

We examined whether the Rho/Rho-kinase pathway is involved in the pathogenesis of nephrosclerosis in severely hypertensive rats and assessed the effects of long-term treatment with a Rho-kinase inhibitor, fasudil, on kidney function, histological findings, gene expressions, and survival. We also attempted to elucidate the mechanisms involved.

METHODS

We studied the following four groups: control Wistar-Kyoto rats (WKY), untreated salt-loaded spontaneously hypertensive stroke-prone rats (SHR-SP), low-dose fasudil (15 mg/kg per day)-treated SHR-SP, and high-dose fasudil (30 mg/kg per day)-treated SHR-SP. After 8 weeks' treatment, the effects of fasudil were examined.

RESULTS

Untreated SHR-SP were characterized by increased blood pressure without circadian variation, decreased kidney function, abnormal renal morphological findings, and increased messenger RNA expression levels of transforming growth factor beta, collagen I, collagen III, p40phox, p47phox, plasminogen activator inhibitor 1, and intracellular adhesion molecule 1 in the renal cortex, compared with WKY. Long-term high-dose fasudil treatment significantly improved renal function (serum creatinine -32%, creatine clearance +39%), proteinuria (-92%) and histological findings (glomerular injury score -57%, arteriolar injury score -55%, fibrous area -40%, ED-1-positive cells -43%) without changing blood pressure or circadian variation, compared with untreated SHR-SP. In addition, fasudil significantly improved increased mRNA expression levels in the renal cortex. Furthermore, high-dose fasudil significantly prolonged survival time compared with untreated SHR-SP (P < 0.01). Low-dose fasudil treatment improved these variables slightly, but did not affect most significantly.

CONCLUSION

The Rho/Rho-kinase pathway participates in the pathogenesis of nephrosclerosis in SHR-SP independently of blood pressure-lowering activity, partly by upregulation of the gene expressions of extracellular matrix, oxidative stress, adhesion molecules, and antifibrinolysis.

Hepatocyte growth factor has protective effects on crystal-cell interaction and crystal deposits

OBJECTIVES

To investigate whether hepatocyte growth factor (HGF) has a protective role against crystal-cell interaction and crystal deposits in a stone-forming rat model kidney. Crystal-cell interaction is an important step during the early stages of stone formation. High oxalate levels induce cell injuries and increase adhesion of calcium oxalate monohydrate (COM) crystals to renal tubular cells. HGF was initially identified as the most potent growth factor for hepatocytes and is well known as a mesenchyme-derived pleiotropic factor for various types of cells. HGF has mitogenic, morphogenic, and anti-apoptotic effects on renal tubular cells.

METHODS

Madin-Darby canine kidney cells were exposed to potassium oxalate or COM crystals in the presence or absence of HGF. We measured lactate dehydrogenase activity in the medium and analyzed apoptosis by FACScan. COM crystal formation was induced by administration of 0.5% ethylene glycol in the drinking water and forced feeding of 0.5 microg of 1alpha-OH-D3 every other day to male Sprague-Dawley rats. Plasmid vector encoding HGF was transferred to stone-forming rats on day 1, and the kidneys were excised on day 8.

RESULTS

Exposure of Madin-Darby canine kidney cells to both potassium oxalate (KOX) and COM crystals resulted in an increase in lactate dehydrogenase release and the proportion of apoptotic cells, but these effects were reduced by HGF. HGF had inhibitory activity against the adhesion of COM crystals to Madin-Darby canine kidney cells. HGF gene transfer significantly reduced crystal deposits on the renal tubules in stone-forming rats.

CONCLUSIONS

These findings suggest that HGF might play an important role in stone formation.

Mechanisms of progression and regression of renal lesions of chronic nephropathies and diabetes

The incidence of chronic kidney diseases is increasing worldwide, and these conditions are emerging as a major public health problem. While genetic factors contribute to susceptibility and progression of renal disease, proteinuria has been claimed as an independent predictor of outcome. Reduction of urinary protein levels by various medications and a low-protein diet limits renal function decline in individuals with nondiabetic and diabetic nephropathies to the point that remission of the disease and regression of renal lesions have been observed in experimental animals and even in humans. In animal models, regression of glomerular structural changes is associated with remodeling of the glomerular architecture. Instrumental to this discovery were 3D reconstruction studies of the glomerular capillary tuft, which allowed the quantification of sclerosis volume reduction and capillary regeneration upon treatment. Regeneration of capillary segments might result from the contribution of resident cells, but progenitor cells of renal or extrarenal origin may also have a role. This review describes recent advances in our understanding of the mechanisms and mediators underlying renal tissue repair ultimately responsible for regression of renal injury.

Angiotensin II type 1 receptor antagonist and angiotensin-converting enzyme inhibitor altered the activation of Cu/Zn-containing superoxide dismutase in the heart of stroke-prone spontaneously hypertensive rats

Although angiotensin II type 1 (AT1) receptor antagonists and angiotensin-converting enzyme (ACE) inhibitors are known to reduce both reactive oxygen species (ROS) generated by activated NAD(P)H oxidase and vascular remodeling in hypertension, the effects of AT1 receptor antagonists or ACE inhibitors on ROS-scavenging enzymes remain unclear. We hypothesized that AT1 receptor antagonists or ACE inhibitors may modulate vascular remodeling via superoxide dismutase (SOD) in hypertension. Male stroke-prone spontaneously hypertensive rats (SHRSP) were treated for 6 weeks with a vehicle, an AT1 receptor antagonist (E4177; 30 mg/kg/day), or an ACE inhibitor (cilazapril; 10 mg/kg/day). We evaluated protein expression using immunoblots, determined SOD activities with a spectrophotometric assay, and measured NAD(P)H oxidase activity by a luminescence assay. The two drugs showed equipotent effects on blood pressure, left ventricular hypertrophy and fibrosis, and endothelial NO synthase in the SHRSP hearts. The wall-to-lumen ratio of the intramyocardial arteries and the NAD(P)H oxidase essential subunit p22(phox) and its activity were significantly reduced, whereas Cu/Zu-containing SOD (Cu/ZnSOD) expression and activity were significantly increased in the SHRSP hearts. Furthermore, E4177 reduced vascular remodeling more than did cilazapril not only by reducing p22(phox) expression and NAD(P)H oxidase activity but also by upregulating the Cu/ ZnSOD expression and its activity in the SHRSP hearts. Thus, both the AT1 receptor antagonist and the ACE inhibitor inhibited vascular remodeling and reduced ROS in SHRSP via not only a reduction in NAD(P)H oxidase but also an upregulation of Cu/ZnSOD.

Up-regulation of Akt and eNOS induces vascular smooth muscle cell differentiation in hypertension in vivo

Recent studies have shown that angiotensin II type 1 (AT1) receptor-mediated Akt activation induces vascular smooth muscle cell (VSMC) dedifferentiation in vitro. However, the critical signal transductions affecting the VSMC phenotype remain unclear in vivo. We examined whether signal transduction through AT1 receptor-mediated reactive oxygen species (ROS) could regulate the VSMC phenotype in stroke-prone spontaneously hypertensive rats (SHRSPs). Male SHRSPs were randomized and treated for 6 weeks with a vehicle, an ACE inhibitor cilazapril, or an AT1 receptor antagonist E4177. The 2 drugs showed equipotent effects on the blood pressure, aortic morphology, and collagen deposition. Both drugs also significantly reduced aortic NAD(P)H oxidase activity and p38MAPK and ERK expression, whereas p-Akt, eNOS, and SM2 were significantly increased in SHRSP aortas. Furthermore, E4177 was more effective than cilazapril at inducing VSMC differentiation by reducing NAD(P)H oxidase activity, and up-regulating p-Akt, eNOS, and SM2. Thus, an ACE inhibitor and an AT1 receptor antagonist inhibited VSMC dedifferentiation through inhibition of NAD(P)H oxidase activity and up-regulation of eNOS and Akt in SHRSP aortas, suggesting that in contrast to the in vitro experiments, AT1 receptor-mediated NAD(P)H oxidase-generated ROS, eNOS, and Akt might be crucial determinants for the VSMC phenotype in hypertension in vivo.

Hepatocyte growth factor induces an endothelin-mediated decline in glomerular filtration rate

Hepatocyte growth factor (HGF) is a multifunctional cytokine that plays a crucial role in renal development, injury, and repair. HGF also serves a protective role in chronic renal disease by preventing tissue fibrosis. Endothelin-1 (ET-1), produced primarily by endothelial cells, is a potent vasoconstrictor that also acts as a proinflammatory peptide, promoting vascular injury and renal damage. In addition to mediating a variety of epithelial cell responses, HGF also induces hemodynamic changes that are poorly understood. The aim of the present study was to study the acute and chronic effects of HGF on ET-1 production in the kidney. We hypothesized that hemodynamic changes upon HGF treatment are likely mediated by immediate ET-1 release, whereas protection from renal fibrosis in rats chronically treated with HGF is likely due to suppression of ET-1 production. Acute HGF infusion into rats caused a decline in blood pressure that was enhanced by pretreatment with bosentan (an endothelin A and B receptor antagonist). HGF infusion also resulted in a decline in glomerular filtration rate (GFR) that could be entirely prevented by bosentan, suggesting that HGF acutely increases production and/or release of ET-1, which then mediates the observed decline in GFR. In cultured glomerular endothelial cells, HGF induced ET-1 production in a dose-dependent manner. Moreover, although there was an initial increase in ET-1 production upon HGF treatment, longer administration suppressed ET-1 production. This finding was consistent with the observation in vivo of a decrease in ET-1 production in renal parenchyma of rats chronically treated with HGF. Our data suggest both a hemodynamic and biological role for HGF-mediated ET-1 regulation.

Effect of antihypertensive agents on stellate cells during liver regeneration in rats

BACKGROUND: Although most studies have focused on the hepatocytes, all the hepatic cells participate in the regenerative process, among them the stellate cells. The stellate cells are mesenchymal cells involved in local neurotransmission and paracrine regulation of several liver functions. Acute hepatic tissue loss promotes the proliferation and activation of stellate cells from a quiescent state to myofibroblast-like cells. AIM: Investigate the effects of antihypertensive agents on the stellate cell population during the liver regenerative phenomenon in rats. METHODS: Adult male Wistar rats received lisinopril, losartan, bradykinin, or saline solution in a proportional volume, intraperitoneally, before and after 70% partial hepatectomy. Animals from the experimental and saline groups were sacrificed at 36 hours after partial hepatectomy. The alpha-smooth muscle actin labelled stellate cells population was counted in the periportal and pericentral zones of the liver specimen. RESULTS: The labelled stellate cells were more numerous in the control group both in the periportal and pericentral zones at 36 hours after partial hepatectomy than at the other times. The population of stellate cells was significantly lower in the losartan group and higher in the bradykinin and lisinopril groups than in the control group. CONCLUSIONS: These results suggest that losartan can inhibit and bradykinin and lisinopril can stimulate the stellate cell population during liver regeneration in rats. These cells synthesize several substances to stimulate liver regeneration.

Hepatocyte growth factor gene therapy and angiotensin II blockade synergistically attenuate renal interstitial fibrosis in mice

Tubulointerstitial fibrosis is considered to be common endpoint result of many forms of chronic renal diseases. Except for renal replacement, chronic renal fibrosis is presently incurable. This study demonstrates that the combination of hepatocyte growth factor (HGF) gene therapy with inhibition of the renin-angiotensin system produced synergistic beneficial effects leading to dramatic attenuation of renal tubulointerstitial fibrosis in obstructive nephropathy in mice. The combined treatment with human HGF gene and losartan, an angiotensin II (AngII) type I receptor blocker, preserved renal mass and gross morphology of the obstructed kidneys. Although HGF gene therapy alone inhibited the expression of alpha-smooth muscle actin (alpha SMA) by approximately 54% and 60% at day 7 and day 14 after surgery, respectively, its combination with losartan almost completely abolished alpha SMA induction in the obstructed kidneys. The combined therapy also synergistically inhibited the accumulation of interstitial matrix components, such as fibronectin and collagen I, and suppressed renal expression of transforming growth factor-beta1 (TGF-beta1) and its type I receptor. In vitro studies revealed that AngII by itself did not induce alpha SMA, but it drastically potentiated TGF-beta1-initiated alpha SMA expression in tubular epithelial cells. Furthermore, HGF abrogated de novo alpha SMA expression induced by TGF-beta1 plus AngII. These results suggest that many factors are implicated in the pathogenesis of renal interstitial fibrosis; therefore, a combined therapy aimed at simultaneously targeting multiple pathologic pathways may be necessary for halting the progression of chronic renal diseases. These findings may provide the basis for designing future therapeutic regimens for blocking progressive renal fibrosis in patients.

TCV-116, an angiotensin II type 1 receptor antagonist, reduces hepatic ischemia-reperfusion injury in rats

BACKGROUND

In Pringle's maneuver during liver surgery and liver transplantation, ischemia-reperfusion (I/R) is an unavoidable process, and protection against hepatic I/R injury is a major unresolved problem. Therefore, various pharmacologic approaches to prevent hepatic I/R injury are currently under trial. In this study, we investigated whether TCV-116, an angiotensin II type 1 receptor antagonist, can reduce this injury.

METHODS

The rats were pretreated either with TCV-116 (group 1) or with the vehicle alone (group 2). The rats in group 3 were not pretreated. Thereafter, they were subjected to partial hepatic I/R.

RESULTS

After reperfusion, the mean peak plasma concentrations of aspartate aminotransferase, alanine aminotransferase, lactic dehydrogenase, and creatine kinase were lower in group 1 than in groups 2 and 3. The magnitude of hepatic injury was reduced in group 1 compared with that in groups 2 and 3. The mean peak plasma concentrations of tumor necrosis factor-alpha, cytokine-induced neutrophil chemoattractants-1, and interleukin-6 were lower in group 1 than in groups 2 and 3. The number of neutrophils infiltrating the liver was also lower in group 1 than in groups 2 and 3. The mean peak plasma concentration of hepatocyte growth factor (HGF) was higher in group 1 than in groups 2 and 3.

CONCLUSIONS

TCV-116 reduced the hepatic I/R injury by inhibiting inflammatory cytokine production and by enhancing HGF production.

Angiotensin-converting enzyme inhibition by lisinopril enhances liver regeneration in rats

Bradykinin has been reported to act as a growth factor for fibroblasts, mesangial cells and keratinocytes. Recently, we reported that bradykinin augments liver regeneration after partial hepatectomy in rats. Angiotensin-converting enzyme (ACE) is also a powerful bradykinin-degrading enzyme. We have investigated the effect of ACE inhibition by lisinopril on liver regeneration after partial hepatectomy. Adult male Wistar rats underwent 70% partial hepatectomy (PH). The animals received lisinopril at a dose of 1 mg kg body weight(-1) day(-1), or saline solution, intraperitoneally, for 5 days before hepatectomy, and daily after surgery. Four to six animals from the lisinopril and saline groups were sacrificed at 12, 24, 36, 48, 72, and 120 h after PH. Liver regeneration was evaluated by immunohistochemical staining for proliferating cell nuclear antigen using the PC-10 monoclonal antibody. The value for the lisinopril-treated group was three-fold above the corresponding control at 12 h after PH (P<0.001), remaining elevated at approximately two-fold above control values at 24, 36, 48 (P<0.001), and at 72 h (P<0.01) after PH, but values did not reach statistical difference at 120 h after PH. Plasma ACE activity measured by radioenzymatic assay was significantly higher in the saline group than in the lisinopril-treated group (P<0.001), with 81% ACE inhibition. The present study shows that plasma ACE inhibition enhances liver regeneration after PH in rats. Since it was reported that bradykinin also augments liver regeneration after PH, this may explain the liver growth stimulating effect of ACE inhibitors.

Obesity, hypertension, and the risk of kidney cancer in men

BACKGROUND

Obesity and hypertension have been implicated as risk factors for the development of renal-cell cancer.

METHODS

We examined the health records of 363,992 Swedish men who underwent at least one physical examination from 1971 to 1992 and were followed until death or the end of 1995. Men with cancer (renal-cell cancer in 759 and renal-pelvis cancer in 136) were identified by cross-linkage of data with the nationwide Swedish Cancer Registry. Poisson regression analysis was used to estimate relative risks, with adjustments for age, smoking status, body-mass index, and diastolic blood pressure.

RESULTS

As compared with men in the lowest three eighths of the cohort for body-mass index, men in the middle three eighths had a 30 to 60 percent greater risk of renal-cell cancer, and men in the highest two eighths had nearly double the risk (P for trend, <0.001). There was also a direct association between higher blood pressures and a higher risk of renal-cell cancer (P for trend, <0.001 for diastolic pressure; P for trend, 0.007 for systolic pressure). After the first five years of follow-up had been excluded to reduce possible effects of preclinical disease, the risk of renal-cell cancer was still consistently higher in men with a higher body-mass index or higher blood pressure. At the sixth-year follow-up, the risk rose further with increasing blood pressures and decreased with decreasing blood pressures, after adjustment for base-line measurements. Men who were current or former smokers had a greater risk of both renal-cell cancer and renal-pelvis cancer than men who were not smokers. There was no relation between body-mass index or blood pressure and the risk of renal-pelvis cancer.

CONCLUSIONS

Higher body-mass index and elevated blood pressure independently increase the long-term risk of renal-cell cancer in men. A reduction in blood pressure lowers the risk.

Novel mechanisms linking angiotensin II and early atherogenesis

We propose that Ang II exerts an as yet uncharacterized immunomodulatory effect on monocyte maturation, differentiation, or extravasation, which may depend on the myelomonocytic phenotype. Since the myelopoietic process originating at stem cells and culminating in release to the blood is at least 6 days, it is conceivable that the observation of reduced monocyte CD11b expression two weeks after completion of losartan treatment indicates a suppression of the CD11b phenotype in newly released CD14(+)/CD45(+) monocytes. Other studies employing suppression of AT(1)-receptors with deoxy-oligonucleotides have reported effects on blood pressure that surpass those predicted by the duration of the treatment.(87) These data would suggest that it is possible to interrupt a stimulatory signal by Ang II through a gene-related mechanism that in our experiments may reside in the mechanisms that regulate myelopoiesis. While our knowledge of the role of Ang II in the regulation of monocyte formation and function is incomplete, we have taken a first step in attempting to synthesize the data described above into a comprehensive hypothesis for further evaluation of the factors that initiate atherogenesis. Such effects may crucially contribute to the clinical benefit of AT(1)-receptor antagonists, independent of depressor effects, and may represent a paradigm for novel, anti-inflammatory actions by this class of drugs.