Resveratrol Protects Cardiac Tissue in Experimental Malignant Hypertension Due to Antioxidant, Anti-Inflammatory, and Anti-Apoptotic Properties

Hypertension is one of the most prevalent and powerful contributors of cardiovascular diseases. Malignant hypertension is a relatively rare but extremely severe form of hypertension accompanied with heart, brain, and renal impairment. Resveratrol, a recently described grape-derived, polyphenolic antioxidant molecule, has been proposed as an effective agent in the prevention of cardiovascular diseases. This study was designed to examine chronic resveratrol administration on blood pressure, oxidative stress, and inflammation, with special emphasis on cardiac structure and function in two models of experimental hypertension. The experiments were performed in spontaneously (SHRs) and malignantly hypertensive rats (MHRs). The chronic administration of resveratrol significantly decreased blood pressure in both spontaneously and malignant hypertensive animals. The resveratrol treatment ameliorated morphological changes in the heart tissue. The immunohistochemistry of the heart tissue after resveratrol treatment showed that both TGF-β and Bax were not present in the myocytes of SHRs and were present mainly in the myocytes of MHRs. Resveratrol suppressed lipid peroxidation and significantly improved oxidative status and release of NO. These results suggest that resveratrol prevents hypertrophic and apoptotic consequences induced by high blood pressure with more pronounced effects in malignant hypertension.

Malignant hypertension: new aspects of an old clinical entity

Malignant hypertension (MHT), also known as accelerated-malignant hypertension or malignant-phase hypertension, is the most severe form of arterial hypertension. It is defined clinically as high blood pressure (BP) levels associated with lesions of the retinal fundus (flame-shaped hemorrhages, exudates, or cotton wool spots, with or without papilledema). Despite the availability of a vast range of antihypertensive agents, MHT continues to be a significant clinical challenge. Although its prevalence is very low, the absolute number of new cases has not changed over the past decades. While the role of the activation of the renin-angiotensin-aldosterone system and endothelial dysfunction in the pathogenesis of MHT has been well described, recent studies have indicated that the immune system may also play an important role in the development of this condition. Patients with MHT are characterized by pronounced target organ damage, including structural and functional cardiac abnormalities. MHT is frequently complicated by renal insufficiency and end-stage renal disease. The survival rates for patients with MHT have improved considerably with increased availability of antihypertensive treatment. However, renal insufficiency and end-stage renal disease still remain a significant cause of morbidity and mortality in this patient group. In conclusion, MHT is not a "vanishing disease" because there is a relatively stable number of new cases per year. Nonetheless, prognosis and survival rates in these patients have improved significantly owing to earlier detection, stricter BP control, lower BP targets, better choice of antihypertensive drugs, and availability of hemodialysis and renal transplantation.

Successful Treatment with an Antihypertensive Drug Regimen Including Eplerenone in a Patient with Malignant Phase Hypertension with Renal Failure

A 28-year-old man was referred to our hospital for the treatment of congestive heart failure and severe hypertension. The patient was diagnosed with malignant phase hypertension based on the presence of marked hypertension with left ventricular hypertrophy, exudate retinopathy, and renal failure. Intensive therapy for hypertension and heart failure with a combination of antihypertensive drugs including nitroglycerin, nifedipine, eplerenone and candesartan successfully lowered his blood pressure and further improved the renal function. Eplerenone could be one of the choices of antihypertensive drugs in combination therapy in patients with malignant phase hypertension with progressive heart and renal failure.

Angiotensin-converting enzyme is a modifier of hypertensive end organ damage

Severe forms of hypertension are characterized by high blood pressure combined with end organ damage. Through the development and refinement of a transgenic rat model of malignant hypertension incorporating the mouse renin gene, we previously identified a quantitative trait locus on chromosome 10, which affects malignant hypertension severity and morbidity. We next generated an inducible malignant hypertensive model where the timing, severity, and duration of hypertension was placed under the control of the researcher, allowing development of and recovery from end organ damage to be investigated. We have now generated novel consomic Lewis and Fischer rat strains with inducible hypertension and additional strains that are reciprocally congenic for the refined chromosome 10 quantitative trait locus. We have captured a modifier of end organ damage within the congenic region and, using a range of bioinformatic, biochemical and molecular biological techniques, have identified angiotensin-converting enzyme as the modifier of hypertension-induced tissue microvascular injury. Reciprocal differences between angiotensin-converting enzyme and the anti-inflammatory tetrapeptide, N-acetyl-Ser-Asp-Lys-Pro in the kidney, a tissue susceptible to end organ damage, suggest a mechanism for the amelioration of hypertension-dependent damage.

[Clinicopathological analysis of malignant nephrosclerosis]

BACKGROUND

Although pathological changes in the vascular lesions of malignant nephrosclerosis have been quantified, little is understood about interstitial changes. We quantified pathological changes such as glomerular damage (glomerular sclerosis and collapse), vascular patency and interstitial fibrosis to determine statistical correlations with clinical data.

METHODS

We examined 25 patients who were diagnosed with malignant hypertension and investigated correlations among age, urinary protein, SUN, 1/Cre, systolic BP and diastolic BP (from medical charts), interstitial fibrosis, glomerular damage, acute tubular damage (semiquantified by scoring) and arterial and arteriolar patency (from renal biopsies).

RESULTS

Interstitial fibrosis inversely correlated with 1/Cre (p=0.0114), interlobular arterial patency (p= 0.0139) and total vascular patency (p = 0.0499). Glomerular damage tended to correlate with urinary protein, but the values did not reach the level of statistical significance (p=0.0666). On the other hand, glomerular damage correlated with neither interstitial fibrosis nor vascular patency. Acute tubular damage closely correlated with both diastolic (p= 0.0086) and systolic (p = 0.0075) BP.

CONCLUSIONS

Interstitial damage increases with decreasing interlobular arterial patency and renal function decreases with increasing interstitial damage. Since acute tubular damage that can progress to chronic interstitial damage closely correlates with BP, the control of BP might indirectly influence the prognosis of renal function.

Aldosterone receptor antagonism alleviates proteinuria, but not malignant hypertension, in Cyp1a1-Ren2 transgenic rats

The contribution of elevated aldosterone to the pathogenesis of malignant, ANG II-dependent hypertension remains uncertain. Therefore, we examined whether chronic mineralocorticoid receptor blockade attenuates the development of malignant hypertension in transgenic rats (TGRs) with inducible expression of the Ren2 gene [TGR(Cyp1a1Ren2)]. Systolic blood pressure (SBP) was measured by radiotelemetry in male TGRs in three groups: 1) control (n = 9), 2) hypertensives (HT; n = 8), and 3) hypertensives + spironolactone (11 mg.kg(-1).day(-1) sc; HTS; n = 8). Malignant hypertension was induced with dietary indole-3-carbinol (0.3%) for 10 days. Metabolic measurements were taken at the beginning of the study and at days 2 and 9. HT exhibited elevated SBP (125 +/- 3 vs. 187 +/- 5 mmHg), plasma renin activity (5 +/- 1 vs. 29 +/- 10 ng ANG I.ml(-1).h(-1)), plasma ANG II (175 +/- 39 vs. 611 +/- 74 fmol/ml), and plasma aldosterone (0.31 +/- 0.04 vs. 5.42 +/- 1.02 nmol/l). Urinary aldosterone excretion increased 5.5-fold by day 2 and an additional 90% by day 9. HT was associated with a 1.8-fold increase in proteinuria by day 9 that was alleviated by treatment with spironolactone (25 +/- 5 vs. 13 +/- 3 mg/day), suggesting that aldosterone contributes to the renal damage observed in malignant hypertension. Urinary Na+ excretion was decreased 76% on day 2, despite a sixfold increase in urinary aldosterone excretion. Decrease in urinary Na+ excretion on day 2 in HT suggests that Na+ reabsorption was increased in response to the increase in aldosterone; however, the lack of a change in SBP between HT and HTS suggests that mechanisms independent of aldosterone stimulation make a greater contribution to the maintenance of elevated arterial pressure in malignant hypertension in Cyp1a1-Ren2 transgenic rats.

Renal vascular and tubulointerstitial inflammation and proliferation in Cyp1a1-Ren2 transgenic rats with inducible ANG II-dependent malignant hypertension

Transgenic rats with inducible ANG II-dependent malignant hypertension [TGR(Cyp1a1Ren2)] were generated by inserting the mouse Ren2 renin gene into the genome of the rat. The present study was performed to assess renal morphological changes occurring during the development of ANG II-dependent malignant hypertension in these rats. Male Cyp1a1-Ren2 rats (n = 10) were fed normal rat food containing indole-3-carbinol (I3C; 0.3%) for 10 days to induce malignant hypertension. Rats induced with I3C had higher mean arterial pressures (173 +/- 9 vs. 112 +/- 11 mmHg, P < 0.01) than noninduced normotensive rats (n = 9). Glomerular damage was evaluated by determination of the glomerulosclerosis index (GSI) in tissue sections stained with periodic acid-Schiff. Kidneys of hypertensive rats had a higher GSI than normotensive rats (21.3 +/- 5.6 vs. 3.5 +/- 1.31 units). Quantitative analysis of macrophage ED-1-positive cells and proliferating cell nuclear antigen using immunohistochemistry demonstrated increased macrophage numbers in the renal interstitium (106.4 +/- 11.4 vs. 58.7 +/- 5.0 cells/mm(2)) and increased proliferating cell number in cortical tubules (37.8 +/- 5.7 vs. 24.2 +/- 2.1 cells/mm(2)), renal cortical vessels (2.2 +/- 0.5 vs. 0.13 +/- 0.07 cells/vessel), and the cortical interstitium (33.6 +/- 5.7 vs. 4.2 +/- 1.4 cells/mm(2)) of hypertensive rat kidneys. These findings demonstrate that the renal pathological changes that occur during the development of malignant hypertension in Cyp1a1-Ren2 rats are characterized by inflammation and cellular proliferation in cortical vessels and tubulointerstitium.

Quantification of topological changes in retinal vascular architecture in essential and malignant hypertension

OBJECTIVE

Grading of hypertension severity by fundoscopic appearance is difficult and inaccurate. We investigated whether essential hypertension (EHT) and malignant phase hypertension (MHT) were associated with quantifiable abnormalities of the topology and architecture of the retinal circulation.

METHODS

The topology and architecture of the retinal microvasculature were compared in images from 20 normotensive subjects, 20 patients with EHT and 20 patients with MHT. Digitized retinal photographs were analysed by a novel multiscale image analysis method using a semi-automated program to quantify geometrical and topological properties of arteriolar and venular trees.

RESULTS

EHT was associated with an increase in the arteriolar length-to-diameter ratio (P < 0.01). There were also alterations in arteriolar topology indicative of rarefaction, including a marked reduction in the number of terminal branches in EHT (P < 0.01). These changes in the arteriolar network were exaggerated in MHT and there was also increased venular tortuosity and venular rarefaction in MHT compared with normotensive subjects.

CONCLUSIONS

Hypertension is associated with marked topological alterations in the retinal vasculature, and quantification of these changes may be a useful novel approach to the assessment of target organ damage in hypertension.

Long-term administration of rho-kinase inhibitor ameliorates renal damage in malignant hypertensive rats

We have shown recently that fasudil, a Rho-kinase inhibitor, has renoprotective effects in salt-sensitive hypertensive rats. We hypothesized that activation of Rho-kinase is involved in the pathogenesis of glomerulosclerosis in malignant hypertensive rats. To test this hypothesis, we studied the following 4 groups: control Wistar-Kyoto rats, untreated deoxycorticosterone-acetate salt spontaneously hypertensive rats (DOCA-SHR), low-dose fasudil-treated DOCA-SHR, and high-dose fasudil-treated DOCA-SHR. After 3 weeks of treatment, the effects of fasudil were examined. DOCA-SHR was characterized by increased blood pressure (BP); increased kidney weight; decreased renal function; increased proteinuria; abnormal histological findings; increased monocyte/macrophage infiltration; increased urinary 8-isoprostran levels; increased gene expression of collagen I, collagen III, transforming growth factor-beta, and reduced nicotinamide-adenine dinucleotide phosphate oxidase subunits (p40phox, p47phox, and p67phox); and decreased gene expression of endothelial NO synthase (eNOS) in the renal cortex as compared with Wistar-Kyoto rats. Long-term high-dose fasudil treatment significantly improved renal function and histological findings without changing BP, as compared with untreated DOCA-SHR. Interestingly, long-term fasudil treatment significantly decreased monocyte/macrophage infiltration and urinary 8-isoprostran excretion, in association with decreased mRNA levels of transforming growth factor-beta, collagen I, collagen III, and NADPH oxidase subunits (p40phox, p47phox, and p67phox), and increased mRNA levels of eNOS in the renal cortex. Long-term low-dose fasudil treatment tended to improve these variables slightly but did not affect most of them significantly. Our results suggest that long-term fasudil treatment provides renoprotective effects independent of BP-lowering activity. These renoprotective effects are associated with inhibition of extracellular matrix gene expression, monocyte/macrophage infiltration, oxidative stress, and upregulation of eNOS gene expression.

[Clinical reasoning and decision making in practice. A 39-year-old woman with somnolence, hypertension and haemolysis]

A 39-year-old woman was admitted with somnolence, severe hypertension and thrombotic microangiopathy. Both malignant hypertension and thrombotic thrombocytopenic purpura (TTP) were considered. Immediate therapy was instituted to treat both diseases because of severe clinical deterioration. Eventually, TTP was considered less likely due to the presence of grade IV hypertensive retinopathy (papilloedema and soft exudates) and a normal Von Willebrand factor-cleaving protease level. Differentiating TTP from malignant hypertension can be difficult as both diseases have similar clinical, laboratory and radiological features. In both diseases, hypertension, thrombotic microangiopathy and encephalopathy with white-matter lesions in the posterior regions of the brain may be apparent. Funduscopic abnormalities consistent with grade III and IV hypertensive retinopathy are rare in TTP, as are normal levels ofVon Willebrand factor-cleaving protease. Therefore, the diagnosis TTP was considered less likely and plasmapheresis was stopped. Hereafter, the laboratory values pointing towards haemolysis remained normal with adequate blood pressure control supporting the rejection of TTP as the cause of the symptoms.

Malignant hypertension in patients with idiopathic IgA nephropathy

BACKGROUND

Idiopathic IgA nephropathy is one of the main causes of secondary malignant hypertension, especially in Chinese population. But little information has been available about malignant hypertension secondary to IgA nephropathy (IgANMHT). The purpose of this study is to evaluate the clinico-pathological features and outcomes of IgANMHT patients.

METHODS

A case control retrospective study was carried out in 45 cases of IgANMHT and 26 cases of primary malignant hypertension (PMHT) diagnosed by renal biopsy. Their clinical features and pathological findings were investigated. Their average follow-up time was 37.4 months. Univariate analysis and multivariate Cox regression analysis were performed to select variables to predict renal survival.

RESULTS

In the study, 1.2% of all the IgA nephropathy patients presented malignant hypertension. The amounts of urine protein excretion and red blood cells in IgANMHT patients were significantly higher, while the levels of serum creatinine were significantly lower than those in PMHT patients. The glomerular injury in IgANMHT patients was more severe than that in PMHT patients. The two characteristic vascular lesions of primary malignant hypertension, proliferative endoarteritis and fibrinoid necrosis were also found in IgANMHT patients but with less severity. Renal survival of IgANMHT patients was significantly higher than that of PMHT patients (p = 0.0043). However, log-rank test showed no significant difference in the renal survival between IgANMHT and PMHT patients with similar SCr levels at admission. Multivariate Cox regression analysis revealed that a high amount of urine protein excretion(> or =1.5 g/24 h), mesangial proliferation and elevated serum creatinine (> or =2 mg/dl) were statistically independent risk factors for renal prognosis (RR = 1.90, 2.72, 2.84, respectively). Conversely, strict blood pressure control had a favorable effect on renal prognosis.

CONCLUSION

The clinico-pathological features and outcomes of IgANMHT patients were different from those of PMHT patients. The renal survival of IgANMHT patients was poor, which was determined by many factors. Early control of proteinuria, early monitoring and strictly controlling blood pressure may contribute to the renal survival.

[Innate and acquired immunity in angiotensin-induced malignant hypertension]

Participation of the immune system in angiotensin (Ang) II-induced endorgan damage is not a conventionally accepted idea. Nevertheless, we have evidence from a double-transgenic rat model of malignant hypertension that Ang II leads not only to activated innate immunity via NF-kB, but also to activated acquired immunity via dendritic cells. By means of surface markers, we observed dendritic cell maturation, migration, and contact with CD4 and CD8 lymphocytes in hearts and kidneys of double-transgenic rats. Treatment with dexamethasone or etanercept provides protection in this model, independent of arterial blood pressure-related effects. Our preliminary data implicate innate immunity and acquired immunity. Both cell-mediated and antibody-mediated effects are involved in the latter in this model.

[Comparative morpho-functional assessment of the impact produced by prolonged infusions of prostaglandins E and F on the course of genetically preconditioned arterial hypertension]

The administration of prolonged intravenous infusions of prostaglandins is defined; the method provided for specifying a long-term impact produced by prostaglandins on a nature of the course of genetically preconditioned arterial hypertension (AHT) in rats. Infusions of PGE-2 bring about a prolonged and stable reduction of mean arterial presser (AP) by 10% versus its original value; they intensify 2-fold the depressor baroreflectory regulation and stimulate the urinary excretion of endogenous renal PGF-2 alpha; besides, they contribute to a better blood supply to organs, i.e. an increased perfusion of the cortical and medullary layers of the kidneys and of the brain substances; and dilatation of the intramural branches of the coronary arteries, due to which the AP becomes milder. Infusions of PGF-2 alpha contribute to a prolonged and stable elevation of mean AP by 12% versus the original value; they inhibit the depressor baroreflectory regulation and intensify the pressor baroreflectory regulation; they, additionally, induce the urinary excretion of endogenous renal PGF-2 alpha and correct the lesions in the blood supply to organs, i.e. pathological microcirculation, anemia and spasm of the renal parenchyma, ischemic foci in the myocardium, spastic contraction of small cerebral arteries, edema and destructive changes (of the local necrosis variation) in the cerebral substance microvessels concomitant with a commencing diapedetic hemorrhages. Finally, all above listed lesions are signs of the malignant AP course.

Focal segmental glomerulosclerosis in malignant hypertension

OBJECTIVE

Focal segmental glomerulosclerosis (FSG) may occur in primary malignant hypertension (MHT) either as a result of glomerular hyperfiltration or fibrinoid necrosis (FN), and may contribute to renal dysfunction. To determine the frequency of occurrence and distribution of FSG in primary MHT we studied renal biopsy specimens from 38 black Africans--30 postmortem and 8 needle-biopsy specimens.

SUBJECTS

There were 31 male subjects and 7 female, with a mean age of 46 (+/- 7) years.

RESULTS

Mean blood pressure (BP) was 206 +/- 15/137 +/- 9 mmHg, median 24-hour proteinuria (interquartile (IQ) range) was 5.1 g (3.3-6.5 g), median serum albumin 3.4 g (3.2-3.8 g) and median serum creatinine 540 mumol/l (425-752 mumol/l). Mucoid intimal proliferation was present in all the sections but FN was seen in 29 (76%). Glomerulosclerosis was present in all the sections, and was axially distributed in 7 (18%), segmentally in 22 (58%), and globally in 9 (24%). Median 24-hour proteinuria was 2.8 g (0.8-3.5 g IQ range), 5.6 g (1.7-8.1 g) and 3.4 g (2.6-4.0 g) respectively, and corresponding values of serum creatinine were 770 mumol/l (106-1,274 mumol/l IQ range), 522 mumol/l (248-991 mumol/l) and 1,230 mumol/l (920-1,558 mumol/l) respectively.

CONCLUSION

The distribution of glomerulosclerosis did not appear to relate to proteinuria or serum creatinine, although cases with segmentally distributed glomerulosclerosis appeared to have the highest proteinuria, and those with global glomerulosclerosis appeared to have the highest serum creatinine levels. FSG therefore occurs prominently in primary MHT and may contribute to renal dysfunction.

Association of the D allele of the angiotensin I converting enzyme polymorphism with malignant vascular injury

AIMS

To determine whether there is an association between the insertion/deletion (I/D) polymorphism of the human angiotensin I converting enzyme (ACE) gene and malignant vascular injury (MVI).

METHODS

The polymerase chain reaction was used to genotype DNA extracted from archival, paraffin wax embedded renal biopsy material from 48 patients with MVI, made up from cases of malignant hypertension (n = 23), scleroderma (n = 10), and haemolytic uraemic syndrome (n = 15), and from whole blood samples from 191 healthy controls.

RESULTS

The D allele was found more frequently in cases of MVI than in healthy controls, (65% v 52%). Both the DD and I/D genotypes occurred significantly more frequently in patients with MVI than did the II genotype (chi(2) = 7.26, p = 0.007; and chi(2) = 4.06, p = 0.04, respectively).

CONCLUSIONS

Possession of at least one copy of the D allele is associated with an increased risk of developing MVI. Our data support a dominant mode of effect for the D allele. Use of the I/D polymorphism as a genetic marker for MVI may be of value clinically in identifying at risk individuals before the development of target end organ damage. Furthermore, those at risk may benefit from early ACE inhibition.

Chronic treatment with a superoxide dismutase mimetic prevents vascular remodeling and progression of hypertension in salt-loaded stroke-prone spontaneously hypertensive rats

Oxidative stress has been implicated in the pathogenesis of hypertension. The aim of the present study was to determine whether increased generation of vascular superoxide anion (*O2-) contributes to blood pressure elevation by influencing vascular function and structure in severely hypertensive rats. Sixteen-week-old stroke-prone spontaneously hypertensive rats (SHRSP) (n = 12) were randomly divided into two groups to receive the superoxide dismutase mimetic, tempol (4-hydroxy-2,2,6,6-tetramethyl piperidinoxyl) (1 mmol/L in drinking water) or tap water. Both groups were fed a high-salt diet (4% NaCl). Systolic blood pressure (SBP) was measured weekly for 6 weeks by the tail-cuff method. Rats were killed, and vascular structure (media:lumen ratio) and endothelial function (acetylcholine [Ach]-induced vasodilation) were assessed in small mesenteric arteries mounted as pressurized preparations. Vascular *O2- concentration was measured by lucigenin (5 micromol/L) chemiluminescence. Plasma total antioxidant status was assessed spectrophotometrically. The SBP increased significantly (P < .01) in the control group, whereas progression of hypertension was prevented in the tempol-treated group. Tempol reduced (P < .01) the media:lumen ratio (7.2%+/-0.01%) compared with that in controls (12.0%+/-0.01%). Maximal Ach-induced dilation was altered in control rats (40%+/-9%) but was not influenced by tempol (57%+/-17%). Vascular *O2- concentration was lower (P < .01) and plasma total antioxidant concentration was higher (P < .05) in the treated group compared with the control. In conclusion, tempol prevents progression of hypertension. These processes are associated with attenuated vascular remodeling, decreased vascular *O2- concentration, and increased antioxidant status. Our data suggest that oxidative stress plays an important role in vascular damage associated with severe hypertension in salt-loaded SHRSP.

[Malignant hypertension presenting with renal damage: a clinical and pathological analyses]

OBJECTIVE

To evaluate the clinical features and pathological characteristics of malignant hypertension (MHPT) with renal damage.

METHODS

The blood pressure, eye ground, urinalysis, renal function and extrarenal presentations of malignant hypertension patients, who had been hospitalized in recent eleven years, were analyzed retrospectively. There were 27 patients, 21 males and 6 females, aged from 19 to 51 years. At the same time, the clinical and pathological features of primary MHPT were compared with those of renal parenchymal MHPT.

RESULTS

Among these patients, primary hypertension was diagnosed in 10 cases (37%), glomerulonephritis in 10 cases (37%), renovascular hypertension in 1 case (3.7%), and undetermined etiology in 6 cases (22.3%). The common renal presentations were those of rapidly progressive glomerulonephritis (RPGN) and progressive renal failure. Compared with those who were diagnosed as renal parenchymal MHPT, primary MHPT patients had lower urinary protein excretion (P = 0.001) and most of them had family history of hypertension. Renal biopsy was done in 13 cases, revealing primary MHPT in 4 cases and glomerulonephritis in 9. Typical pathological findings for primary MHPT were fibroid necrosis, marked intimal hyperplasia ("onion skin" like change) and ischemic changes of glomeruli. Severe glomerulonephritis, hyalinosis and thickening of renal arterioles were the main changes in MHPT with renal parenchymal diseases. After intensive therapy, the renal functions of some primary MHPT patients improved markedly.

CONCLUSION

Malignant hypertension presenting with renal damage was not very rare. It was usually misdiagnosed. The clinical presentations, pathological findings and prognosis of primary MHPT were different from those of renal parenchymal MHPT.

Control of blood pressure and prevention of end-organ damage in patients with accelerated hypertension by combination with arotinolol and extended release nifedipine

In patients with accelerated (malignant) hypertension, end-organ damage is the determinant factor for prognosis. Although recent advances in antihypertensive therapy have improved the outcome of patients with accelerated hypertension, the effectiveness of antihypertensive therapy still remains less convinced. In this study, we followed 13 patients clinically diagnosed with accelerated hypertension (defined as diastolic blood pressure > 130 mmHg, retinopathy with K-W IV and accelerated renal impairment) for 3 yr. One patient died due to acute myocardial infarction arising from poor compliance with antihypertensive therapy. One patient was maintained on hemodialysis for 3 yr. One patient was introduced for continuous ambulatory peritoneal dialysis (CAPD) for a year and then lived without dialysis therapy. The remaining 10 patients were followed for 3 yr. All patients were initially treated with intravenous administration of calcium antagonist for reduction of blood pressure, followed by hemodialysis therapy if needed. After stabilization of blood pressure, combination therapy with extended release nifedipine (40 to 80 mg daily) and arotinolol (20 mg daily) was started. The targets for blood pressure control were a systolic pressure of 135 mmHg and a diastolic pressure of 80 mmHg. If blood pressure control was unsatisfactory, guanabenz (2 to 4 mg before bedtime), a central acting drug, was added. At presentation, the mean diastolic blood pressure (mDBP) among the 10 remaining patients was 134 +/- 2 mmHg, the mean serum creatinine (mScr) was 4.5 +/- 0.7 mg/dl and the left ventricular mass index (LVMi) as measured by echocardiography was 150 +/- 9 g/m2. At 1 yr, the mDBP was reduced to 90 +/- 3 mmHg, the mScr to 2.9 +/- 0.9 mg/dl and the LVMi to 140 +/- 9 g/m2. At 3 yr, the mDBP was stabilized at 79 +/- 3 mmHg, the mScr maintained at 2.2 +/- 0.4 mg/dl, and the LVMi reduced to 128 +/- 9 g/m2. These results indicate that appropriate blood pressure control is important for improvement of renal impairment and cardiac damage in patients with accelerated hypertension. Moreover, combination therapy with arotinolol and extended release nifedipine may be beneficial for this purpose.

Malignant hypertension with a rare complication of pulmonary alveolar hemorrhage

A 34-year-old Japanese male was admitted to Okayama University Hospital with severe hypertension, rapidly progressive renal failure, blurred vision, dyspnea and hemoptysis. Clinical diagnosis of malignant hypertension was given and antihypertensive therapy and hemodialysis were immediately started. Renal biopsy was performed on the sixth day in hospital to examine the underlying disease, such as microscopic form of polyarteritis, since the complaint of hemoptysis and pulmonary alveolar hemorrhage was noted by computed tomography of the lungs. Typical pathological changes of malignant hypertension, i.e. fibrinoid necrosis of the afferent arterioles and proliferative endoarteritis at the interlobular arteries were observed. There was no evidence of active necrotizing glomerulonephritis and crescent formation. Renal function was gradually recovered and pulmonary hemorrhage completely disappeared by treatment with antihypertensive agents. The authors report a case of malignant hypertension with a rare complication of pulmonary alveolar hemorrhage and speculate that it may be related to vascular injuries at the alveolar capillary level caused by malignant hypertension.

Nephroprotection by long-term ACE inhibition with ramipril in spontaneously hypertensive stroke prone rats

BACKGROUND

The effect of life-long treatment with the ACE inhibitor ramipril on hypertension-induced histological changes in the kidney was tested in stroke-prone spontaneously hypertensive rats (SHR-SP).

METHODS

One-month-old pre-hypertensive SHR-SP were randomized into three groups of 45 animals each, and exposed via drinking water for their lifetime to a dose of: 1 mg.kg-1.d-1 ramipril (antihypertensive dose, HRA); 10 micrograms.kg-1.d-1 slight dose of ramipril (non-antihypertensive dose, LRA); or placebo. Histological and biochemical assessments were conducted after 15 months in ten rats each, when about 80% of the placebo group had died.

RESULTS

Kidneys from placebo treated SHR-SP showed pronounced arterial wall hypertrophy and sclerosis, arterial fibrinoid necrosis, glomerulopathy and tubular interstitial injury that were, in concert with normalized blood pressure, completely prevented by HRA treatment. LRA treatment did not affect any blood pressure increase, and also attenuated the development of arterial wall hypertrophy, sclerosis and arterial fibrinoid necrosis, though to a minor extent only, but did not change glomerular and tubulointerstitial degeneration. These effects of ramipril were associated with a dose-dependent inhibition of plasma and renal tissue ACE activities as well as lower serum concentrations of creatinine, but there were no changes in serum potassium.

CONCLUSIONS

Life-long HRA-induced ACE inhibition protects against hypertension-induced renal damages in SHR-SP. This is associated with a doubling of the lifespan in these animals.

[Scleroderma renal crisis. 7 cases and review of the literature]

We report a series of seven patients who had scleroderma renal crisis. Their primary clinical and laboratory features along with the details of their management were compared with those of similar cases from the literature. The seven patients died within one to four months of the diagnosis with a pattern of acute renal failure, left ventricular failure and malignant hypertension. Histopathologic examination was performed in four of the patients, in two of whom it revealed thickening of the wall of the interlobular arteries related to the scleroderma, and in the other two patients nonspecific lesions of malignant hypertension. This histopathologic particularity led us to propose, on the basis of multiple renal biopsies performed in patients with scleroderma, a lesion chronology of the kidney in patients with scleroderma. Nevertheless, the triggering factors and pathophysiologic mechanisms of scleroderma renal crisis remain unclear and its prognosis is severe. Early treatment with angiotensin-converting enzyme inhibitors and other vasodilatators administered intravenously can prevent death and dialysis.

Malignant hypertension and hypertensive emergencies

Hypertensive emergencies and urgencies are important causes of morbidity and mortality. Malignant hypertension is a hypertensive urgency characterized by grade III/IV retinopathy and widespread endothelial damage. Control of BP is essential in the treatment of these disorders. The effects of hypertension on target organ function need to be balanced against the risks of excessive BP lowering. In hypertensive emergencies, BP should be lowered within minutes with parenteral agents to prevent critical end-organ damage. In hypertensive urgencies, BP can be lowered more slowly over several hours, often with oral agents, to avoid a detrimental fall in BP. The absolute indications for treatment and the optimal therapy depend on the underlying condition.

Hypertensive arteriolar necrosis revisited

Arteriolar necrosis is the histopathological hallmark of malignant hypertension. In the period from 1940 to 1980, intensive studies of the pathogenesis of hypertensive fibrinoid necrosis were carried out. From studies of mesenteric vessels in animals with experimental hypertension it was discovered that arteriolar necrosis is preceded by an abnormal vascular reaction pattern consisting of alternating constriction and localized dilatations. The development of the abnormal reaction pattern is followed by endothelial hyperpermeability resulting in transsudation of plasma and macromolecules into the wall of the arteriole. The hyperpermeability, and, in turn, arteriolar necrosis, is exclusively found in the dilated segments of the vessel. The abnormal vascular reaction pattern can be induced experimentally by various techniques such as infusion of angiotensin II or stimulation of perivascular nerves, and it can be demonstrated in all target organs. Since 1980 a remarkable falling-off in the research on the pathogenesis of hypertensive arteriolar necrosis has been noted. Recent studies in this area utilizing current knowledge and major advances in microvascular research methods are very few in number. As of today, the chain of pathogenetic processes leading eventually to the all-important lesion of arteriolar fibrinoid necrosis remains poorly understood.

High human renin hypertension in transgenic rats

We developed a model of spontaneously high human renin hypertension in the rat by producing two transgenic strains, one for human angiotensinogen with the endogenous promoter and one for human renin with the endogenous promoter. Neither transgenic strain was hypertensive. These strains were then crossed, producing a double transgenic strain. The double transgenic rats, both males and females, developed severe hypertension (mean systolic pressure, 200 mm Hg) and died after a mean of 55 days if untreated. The rats had a human plasma renin concentration of 269 +/- 381 (+/-SD) ng angiotensin I (Ang I)/mL per hour, plasma renin activity of 177 +/- 176 ng Ang I/mL per hour, rat angiotensinogen concentration of 1.49 +/- 1 microgram Ang I/mL, and human angiotensinogen concentration of 78 +/- 39 micrograms Ang I/mL (n = 49). Control rats had plasma renin activity of 3.7 +/- 3.9 ng Ang I/mL per hour and rat angiotensinogen of 1.32 +/- 0.16 micrograms Ang I/mL. Angiotensinogen transgene expression by RNase protection assay was ubiquitously present but most prominent in liver. Renin transgene expression was high in kidney but absent in liver. The rats featured severe cardiac hypertrophy, with increased cross section of cardiomyocytes but little myocardial fibrosis. The kidneys showed atrophic tubules, thickened vessel walls, and increased interstitium. Both the angiotensin-converting enzyme inhibitor lisinopril and the specific human renin inhibitor remikiren lowered blood pressure to normal values. Double transgenic mice have been developed that exhibit features quite similar to those described here; their gene expressions are similar. The specificity of rodent and human renin is similarly documented. Although many elegant physiological studies can now be done in mice, rats nevertheless offer flexibility, particularly in terms of detailed cardiac and renal physiology and pharmacology. We conclude that this double transgenic strain will facilitate simultaneous investigation of genetic and pathophysiological aspects of renin-induced hypertension. The fact that human renin can be studied in the rat is a unique feature of this model.

Renal and vascular effects of chronic endothelin receptor antagonism in malignant hypertensive rats

The effect of the combined ETA/ETB endothelin receptor antagonist bosentan on blood pressure, vascular hypertrophy, and pathologic renal changes was investigated in a model of malignant hypertension, severe vascular hypertrophy, and enhanced vascular expression of endothelin-1, the deoxycorticosterone acetate (DOCA), and salt-treated spontaneously hypertensive rat (SHR). DOCA-salt treated SHR received 100 mg bosentan per kilogram weight per day mixed with their food. Systolic blood pressure of untreated DOCA-salt SHR rose to 241 +/- 1.5 mm Hg, whereas that of bosentan-treated rats rose to 221 +/- 5.1 mm Hg (P < .01). Cardiac and conduit artery mass were not affected by treatment. Small arteries from the coronary, renal, and mesenteric circulations showed a smaller media width and cross-sectional area of the media in rats treated with bosentan than in untreated rats. The kidneys showed the presence of fibrinoid necrosis in a high percentage of afferent arterioles and glomeruli of untreated DOCA-SHR. Some kidneys of treated rats exhibited less severe vascular hypertrophy and lesser extent of vascular or glomerular fibrinoid necrosis, but the renal injury score of bosentan-treated DOCA-SHR was only at the limit of significance from that of untreated rats (P = .06). These results suggest a role for endothelin-1 in blood pressure elevation and the severe vascular hypertrophy of small arteries of the coronary, renal, and mesenteric vasculature, but not of the heart or larger conduit vessels in the malignant hypertension that SHR develop after treatment with DOCA and salt. Although some bosentan-treated rats showed fewer renal lesions, a significant effect on renal pathology could not be unambiguously demonstrated. Further studies will be necessary to determine whether endothelin antagonists may indeed offer some degree of renal protection and have therapeutic potential in severe or malignant hypertension.

Long-term therapeutic effects of ace inhibitor and calcium antagonists on hypertensive vascular lesions in M-SHRSP

1. Our results indicate that the drugs used in this study are very effective in malignant hypertension therapy. 2. For M-SHRSP treated with highly effective antihypertensive drugs, if blood pressure remains under 200 mmHg over the long-term, the structures of the small arteries and/or arterioles stay as well preserved as they do in WKY. 3. For M-SHRSP treated with drugs with a lower antihypertensive effect, the occurrence of cerebrovascular lesions and angionecrosis in the various organs are suppressed significantly, even though blood pressure remains over 250 mmHg over the long-term. Based upon effect alone, there is no difference between ACEI and a calcium antagonist. However, inhibition of the proliferation of vascular smooth muscle cells is more potent in the former than in the latter. 4. These results suggest that ACEI might have the potential to suppress smooth muscle cell proliferation independent of high blood pressure.

Electroencephalographic evaluation of the therapeutic efficiency of antihypertensive agents on M-SHRSP

1. In order to evaluate the therapeutic effects of antihypertensive agents on malignant hypertension in M-SHRSP, EEG were performed as a non-invasive, therapeutic index. 2. Under pentobarbital anaesthesia, the EEG pattern of rats with severe hypertension and/or cerebrovascular lesions showed alternate short-active and long-depressive phases with spike and sharp waves. 3. When M-SHRSP were treated with an angiotensin converting enzyme inhibitor (SQ 29,852) or a calcium antagonist (manidipine), the depressive phases became shorter and active phases longer. These changes were more prominent in manidipine treated rats than in SQ 29,852 treated rats. 4. The EEG spike- and sharp-wave complex seems to be a convenient index for evaluating cerebrovascular lesions and cerebral activity in M-SHRSP.

A genetic model of malignant phase hypertension in rats

A genetic model of malignant phase hypertension in rats is described which closely parallels the natural history of untreated human malignant phase hypertension. Although the factors initiating transition from essential hypertension to the accelerated phase in humans remain unknown, we report the characteristics of a genetically determined and reproducible phenotype which was found to result from a cross between hypertensive transgenic Ren-2 rats and normotensive Sprague-Dawley (Edinburgh) rats. Male F1 hybrids developed malignant phase hypertension with a penetrance of 73.5% (95% confidence limits 65.7 to 81.3%) by 100 days of age. Phenotypic features included an accelerated rise in blood pressure, fibrinoid necrosis, activation of the renal renin-angiotensin system and microangiopathic hemolytic anemia. In an analytical cross no significant difference in blood pressure was observed between malignant phase and non-malignant phase animals prior to transition, implying that a factor in addition to hypertension appears necessary for inducing transition to the malignant phase phenotype. Segregation of the malignant phenotype suggested that susceptibility is determined by at most two genetic loci.

Spontaneous development of malignant phase hypertension in transgenic Ren-2 rats

Spontaneous development of malignant phase hypertension in TGR(mREN2)27 heterozygotes occurs as a consequence of crossing TGR(mREN2)27 homozygotes with Edinburgh Sprague-Dawley rats. Similarities to human malignant phase hypertension are seen with an accelerated rise in blood pressure, fibrinoid necrosis of renal afferent arterioles, renal failure and evidence of renin-angiotensin system activation. It appears that introduction of an additional genetic factor or factors into a monogenic model of hypertension results in malignant phase hypertension.

Malignant hypertension in antiphospholipid syndrome without overt lupus nephritis

The antiphospholipid syndrome is usually defined by the association of a clinical manifestation (recurrent venous and/or arterial thrombosis, recurrent spontaneous miscarriages) and a biological abnormality (anticardiolipin antibody, lupus anticoagulant). We retrospectively analyzed the records of 5 patients (4 females, 1 male, aged 30 +/- 12 years) with antiphospholipid syndrome, primary (n = 1) or secondary to systemic lupus erythematosus (n = 4), who developed malignant systemic hypertension with renal insufficiency, in the absence of lupus nephritis. Before the episode of malignant hypertension, all patients had normal systemic blood pressure and renal function. During malignant hypertension the systolic pressure was 206 +/- 39 mmHg and the diastolic pressure 130 +/- 25 mmHg, peak serum creatinine was 204 +/- 95 mumol/l, daily proteinuria was 1.1 +/- 0.8 gr, and complement serum levels were normal in all patients. Renal angiography found normal proximal renal arteries. Renal biopsy showed ischaemic glomeruli without proliferative lesions (n = 5), focal intimal fibrosis either isolated (n = 3) or associated with thrombosis (n = 2) of the intrarenal vessels, and the absence of vasculitis. Immunofluorescence study did not reveal typical lupus deposits. Patients were treated with antihypertensive agents, increasing doses of prednisone (n = 3), and anticoagulant (n = 2) or anti-aggregant therapy (n = 1). After a mean follow-up of 6.8 +/- 5.2 years, 4 patients were still alive with normal blood pressure and renal function, whereas 1 patient died of a probable catastrophic antiphospholipid syndrome. Patients with antiphospholipid syndrome, primary or secondary to systemic lupus erythematosus, may develop malignant hypertension with renal insufficiency and intrarenal vascular lesions, in the absence of lupus nephritis.

Focal pancreatic infarction in pheochromocytoma

A 21-year-old man presenting with jaundice and hypertension was found to have an extraadrenal pheochromocytoma. Cholangiography demonstrated a cavity in the head of the pancreas that was in communication with both the pancreatic and common bile ducts. Hemorrhage from the cavity led to the patient's death and postmortem examination revealed focal infarction of the pancreatic head. This case adds hemobilia, obstructive jaundice, and focal pancreatic infarction to the list of bizarre remote manifestations of pheochromocytoma.

[Ophthalmological study of the M-strain stroke-prone spontaneously hypertensive rats (2). Retinal arteriolar changes in fluorescein angiogram]

Malignant or precocious stroke-prone spontaneously hypertensive rats show severe hypertensive fundus changes such as generalized narrowing, caliber irregularity, and tortuosity of retinal arterioles or retinal edema. In our previous studies, these changes were classified into four grades from 0 to 3 according to severity. In the present study, hypertensive fundus changes in these rats, such as generalized narrowing or caliber irregularity of retinal arterioles, were studied by comparing fluorescein angiographs with color fundus photographs. Fluorescein leakage was observed from retinal vessels in more than half the retinal arterioles with hypertensive caliber irregularity of grade 2. Pathological studies also showed irreversible changes in the retinal arterioles with hypertensive caliber irregularity.

Kidney histology and clinical correlates in malignant hypertension

In this clinico-pathologic study, post-mortem kidney material from 30 cases with malignant hypertension (MHT) defined as severe hypertension with bilateral retinal haemorrhages and exudates (grade III retinopathy) with (grade IV retinopathy) or without papilloedema, were studied. Mucoid intimal proliferation (MIP) in interlobular artery and ischaemic collapse of the glomerular tufts occurred in all cases, whereas fibrinoid necrosis (FN) was seen in only 24 (80%) of the cases. FN was not correlated nor associated with sex, age, blood pressure, retinopathy or serum creatinine. Tubular atrophy and interstitial fibrosis occurred in 24 (80%) and correlated best (rS = 0.8, p < 0.05) with serum creatinine in comparison to glomerular sclerosis (rS = 0.6, p = n.s), fibrinoid necrosis (rS = 0.49, p = n.s) and epithelial crescents (rS = 0.43, p = n.s). This study provides histologic evidence of lack of difference between grades III and IV retinopathy, shows MIP as the more characteristic vascular lesion in MHT and also, good correlation between renal function and tubulointerstitial involvement.

Peripolar cells, granulated glomerular epithelial cells, and their relationship to the juxtaglomerular apparatus in malignant hypertension

We have examined 12 autopsy kidneys from cases of malignant hypertension and compared them with normal controls. Peripolar cells and other granulated glomerular epithelial cells were counted in serial paraffin sections, and renin-containing cells were quantified using an immunoperoxidase technique and a human renin antiserum. There were significantly more peripolar cells and other granulated glomerular epithelial cells in the cases of malignant hypertension. Most granulated glomerular epithelial cells were podocytes, situated at the periphery of the tuft. Peripolar cells correlated in number with other granulated glomerular epithelial cells and they had a similar distribution within the renal cortex, but there was no correlation between either of these cells and the number of renin-containing cells. There was hyperplasia of renin-containing cells in some juxtaglomerular apparatuses (JGAs), although the proportion of renin-positive JGAs was unaltered. These results suggest that peripolar cells and other glomerular epithelial cells react in a similar way in malignant hypertension, but they do not support the hypothesis that peripolar cells are part of the JGA.

Accelerated secretion of brain natriuretic peptide from the hypertrophied ventricles in experimental malignant hypertension

Plasma concentrations of immunoreactive (ir) atrial (ANP) and brain (BNP) natriuretic peptides were measured in the prehypertensive and hypertensive phases in spontaneously hypertensive rats (SHR) and in the malignant phase of hypertension caused by deoxycorticosterone acetate (DOCA)-salt in SHR. The secretory rate of ANP and BNP were examined in the perfusion of isolated beating heart before and after atrial removal. Plasma irANP and irBNP in mature SHR were higher than those of control Wistar-Kyoto (WKY) rats, whereas ANP and BNP values in young SHR did not differ from those of control WKY rats. DOCA-salt treatment for 8 weeks markedly increased blood pressure, ventricular weight, and plasma irANP and irBNP in SHR. ANP and BNP values were positively correlated with ventricular weight in DOCA-salt SHR. The secretory rate of ANP and BNP from the perfused whole heart were much higher in DOCA-salt SHR than other rat groups. A large amount of BNP was secreted from the hypertrophied ventricles in DOCA-salt SHR. In contrast, ANP was mainly secreted from the atrium in all rat groups. High-performance liquid chromatography profiles of extract in plasma showed that a major component of irANP and irBNP corresponded to synthetic rat ANP-(1-28) and rat BNP-45, respectively. Results suggest that both rat ANP-(1-28) and rat BNP-45 are markedly increased in plasma in DOCA-salt-induced malignant hypertension of SHR and that the major source of circulating BNP is the hypertrophied ventricles in this model.

Chronic treatment with captopril, SQ29,852, hydralazine and a 33% fish meal diet in malignant stroke-prone spontaneously hypertensive rats

Malignant stroke-prone spontaneously hypertensive rats (M-SHRSP) are a useful animal model for studying juvenile malignant hypertension. Using M-SHRSP males, the effects of SQ 29,852 [(S)-1-[6-amino-2-[[hydroxy (4-phenylbutyl) phosphinyl]oxy]-1-oxohexyl]-L-proline; 30-40 mg/kg per day], captopril (30-40 mg/kg per day), hydralazine hydrochloride (10-15 mg/kg per day) and a 33% fish meal diet on the prevention and therapy of malignant hypertension were examined. Drugs and diet were given separately, beginning at weaning, maturity or adulthood. Observed effects included antihypertension, prolonged life span and prevention and/or reversal of angionecrosis. Each treatment resulted in an antihypertensive effect, but some adult rats seemed treatment-resistant. SQ 29,852 was the most effective treatment for reducing blood pressure. The life span of animals in the treated groups was extended significantly beyond that of the controls. In particular, those rats treated with either captopril or SQ 29,852 lived in excess of 500 days. This included not only those in which treatment resulted in a lowering of blood pressure, but also those whose severe hypertension was not so reduced. Angionecrosis was observed in the organs of many of the non-treated animals, including the brain, heart, kidneys and testes. Both hydralazine and the fish meal diet had a limited effect, if any, on the prevention or reversal of angionecrosis. In contrast, almost none of the rats given either captopril or SQ 29,852 showed cerebrovascular lesions or angionecrosis of the brain, heart and kidneys; angionecrosis in adult M-SHRSP kidneys disappeared within 10 or 18 days after the initiation of SQ 29,852 or captopril, respectively. This data seems to support a possible role for these two drugs not only in prevention, but also in repair, of angionecrosis independent of markedly high blood pressure in M-SHRSP. Based on our overall observations, SQ 29,852 was seen as the most effective of the treatments studied.

The renal histopathology of essential malignant hypertension in black South Africans

The renal histopathology of essential malignant phase hypertension in two groups of black South Africans was studied. The first, an autopsy series, consisted of material obtained in 1956-1961, a period when adequate antihypertensive therapy had not yet become generally available. The second group, a renal biopsy series, was from an era when effective antihypertensive therapy was available (1979-1989). The study showed that the clinical and histopathological changes of malignant hypertension were similar in both the pre-treatment and treatment eras. Fibrinoid necrosis was found in 92% of the autopsy sections and 44% of the biopsies. While mucinous, onion-skin and fibrotic changes of the blood vessels were commonly found, they were not invariably present and could not be considered the histopathological hallmark of malignant nephrosclerosis. It was often impossible on histological examination to distinguish malignant nephrosclerosis arising de novo from that superimposed on long-standing previous benign hypertension. Replication of internal elastic lamina, which has been considered a marker of long-standing previous benign hypertension, was a nonspecific finding and was frequently observed in young hypertensive subjects with a short clinical history. When fibrinoid necrosis is present, diagnosis of malignant nephrosclerosis can be made with confidence in black South Africans.

Arterial disease of the iris predicts visceral arterial necrosis in rabbits with acute one-kidney, one clip hypertension: comparisons with acute one-kidney, one wrapped hypertension

Tortuosity, dilations, aneurysms and satellite hemorrhages consistently develop in the circular arteries of the iris of rabbits with acute one-kidney, one clip (1K1C) malignant hypertension. These lesions are easily visualized, quantitated and monitored during life. Graded iridoarteriopathy correlates directly with visceral arterial necrosis (r15 = 0.843; P less than 0.001), final indirect blood pressure (r15 = 0.591; P less than 0.02) and cardiac hypertrophy (r15 = 0.565; P less than 0.02). Arterial necrosis in the irises and other viscera in acute 1K1C hypertension in rabbits is qualitatively similar to that occurring in rabbits with acute one-kidney, one wrapped (1K1W) hypertension with regard to both the histological features and organ distribution. However, over three times as many arterial lesions occur in rabbits with acute 1K1W hypertension as occur in those with acute 1K1C hypertension (P less than 0.001). Since blood pressure elevation does not correlate with graded iridoarteriopathy or with visceral arterial necrosis in 1K1W rabbits, factors other than blood pressure elevation appear to be especially important in the pathogenesis of arterial necrosis in the 1K1W model. On the other hand, the present study indicates that high grade iridoarteriopathy appears to be indicative of a high risk of cerebral hemorrhage in 1K1C rabbits, as earlier studies have shown for 1K1W rabbits.

Protracted anuria due to active vasoconstriction in primary or secondary malignant hypertension

Anuria complicated the malignant phase of hypertension in twelve patients (ten males and two females). Five were black; five had primary hypertension; one had HBs virus angiitis; the six remaining cases suffered from previously documented renal disease, including two with Berger's disease. Renal angiography showed interruption of renal blood flow as far as the main branches of the renal artery and/or a false impression of 'cortical necrosis' and of 'renal infarcts'. In contrast, renal biopsy did not show irreversible vascular damage. Thus, anuria was mainly functional and due to active renal vasoconstriction. This was confirmed by the subsequent course; diuresis resumed after 1 week to 24 months of dialysis. Repeat angiography in six cases showed recovery of renal circulation and disappearance of 'cortical infarcts', even when plasma renin activity remained elevated and hypertension was not controlled. In one case captopril induced a new reversible episode of anuria. These observations suggest that active vasoconstriction with prolonged anuria might be due to some vasoconstrictive substance other than angiotensin II.

High-renin malignant hypertension secondary to an aldosterone-producing adenoma

Malignant hypertension and high plasma renin activity was found in a 39-year-old woman with an aldosterone-producing adenoma. Only 3 similar cases have been previously reported, and all patients died before or after identification of the adenoma. The present paper documents the first reported case of a successfully managed high-renin malignant hypertension secondary to an aldosterone-producing adenoma. Regardless of its sporadic occurrence and common presence with low plasma renin activity, primary aldosteronism should be considered as a possible underlying cause of high-renin malignant hypertension.

Histopathology of severe renal vascular damage in blacks

During the 1970s renal biopsies were obtained after blood pressure had been controlled in 41 black patients in Memphis who had severe hypertension plus excretory renal failure. An additional 13 binephrectomy specimens were also studied. This material yielded significant information on the state of the renal arteries--arterioles under these circumstances. Fibrinoid necrosis of the afferent glomerular arteriole and proliferative glomerulitis were not noted. Rather, the vascular lesion characterized by the accumulation of smooth muscle cells and mucopolysaccharide in the intima attended by a marked narrowing of the lumen was dominant. This lesion caused pronounced ischemia associated with obsolescence of glomeruli, atrophy, and fibrosis (end-stage kidney). This lesion has been renamed musculomucoid intimal hyperplasia as a result of changes revealed by electron microscopic and histochemical studies. Since this study the incidence of this severe vascular disease of the kidney in the same geographic area has been markedly reduced. There are a number of possible reasons for this change in incidence, but a major one appears to be improved treatment of hypertension and better compliance with antihypertensive therapy. Why such extreme changes occur in a subset of hypertensive blacks is not known. It is apparent that without improved antihypertensive treatment, this type of end-stage renal disease due to severe vascular damage will continue to be encountered.

[Clinical use of magnetic resonance tomography in the assessment of vital organs in malignant arterial hypertension]

Magnetic resonance tomography was performed to examine the kidneys, brain, adrenals, vessels, and heart in 110 patients with malignant arterial hypertension (MAH). The findings were compared with those of the examination of healthy subjects and patients with benign hypertensive disease (BHD). As compared to the controls, all the MAH patients had changes in the target organs, however, their nature and magnitude varied with under underlying MAH disease. Renal alterations were most profound in chronic glomerulonephritis. All the patients displayed signs of concentrated cardiac hypertrophy: its maximum degree being noted in renovascular hypertension, the least, in MAH of adrenal genesis. Examination of the central nervous system in MAH patients revealed that the ventricular system and subdural space were dilated. It was shown that it was feasible to diagnose hypertrophic encephalopathy in the prehospital period by employing magnetic resonance tomography.

Hypertension in black South Africans--new perspectives on old material

Autopsy material was examined from cases diagnosed as malignant nephrosclerosis in the years 1956-1961, a period when adequate antihypertensive therapy had not yet become available, a second group of malignant nephrosclerosis from the years 1970-1980, an era during which effective antihypertensive therapy was available, and a third group of essential benign nephrosclerosis, once more from the early pretreatment period (1956-1961). The observations suggest that malignant and benign hypertension may be two different diseases. Further studies will be pursued to assess whether hypertensive renal changes seen in this study are a spectrum of one disease extending from malignant nephrosclerosis de novo presenting with acute renal failure or chronic renal failure to benign hypertensive nephrosclerosis.