The effect of cortisone on the serum lipids and on the development of experimental cholesterol atherosclerosis in the rabbit

Sex as a Biological Variable in Atherosclerosis

Atherosclerosis is a chronic inflammatory vascular disease and the predominant cause of heart attack and ischemic stroke. Despite the well-known sexual dimorphism in the incidence and complications of atherosclerosis, there are relatively limited data in the clinical and preclinical literature to rigorously address mechanisms underlying sex as a biological variable in atherosclerosis. In multiple histological and imaging studies, overall plaque burden and markers of inflammation appear to be greater in men than women and are predictive of cardiovascular events. However, while younger women are relatively protected from cardiovascular disease, by the seventh decade, the incidence of myocardial infarction in women ultimately surpasses that of men, suggesting an interaction between sex and age. Most preclinical studies in animal atherosclerosis models do not examine both sexes, and even in those that do, well-powered direct statistical comparisons for sex as an independent variable remain rare. This article reviews the available data. Overall, male animals appear to have more inflamed yet smaller plaques compared to female animals. Plaque inflammation is often used as a surrogate end point for plaque vulnerability in animals. The available data support the notion that rather than plaque size, plaque inflammation may be more relevant in assessing sex-specific mechanisms since the findings correlate with the sex difference in ischemic events and mortality and thus may be more reflective of the human condition. Overall, the number of preclinical studies directly comparing plaque inflammation between the sexes is extremely limited relative to the vast literature exploring atherosclerosis mechanisms. Failure to include both sexes and to address age in mechanistic atherosclerosis studies are missed opportunities to uncover underlying sex-specific mechanisms. Understanding the mechanisms driving sex as a biological variable in atherosclerotic disease is critical to future precision medicine strategies to mitigate what is still the leading cause of death of men and women worldwide.

Drug delivery to atherosclerotic plaques using superparamagnetic iron oxide nanoparticles

INTRODUCTION

Magnetic drug targeting utilizes superparamagnetic iron oxide nanoparticles (SPIONs) to accumulate drugs in specified vasculature regions.

METHODS

We produced SPIONs conjugated with dexamethasone phosphate (SPION-DEXA). The efficacy of magnetic drug targeting was investigated in a rabbit model of atherosclerosis induced by balloon injury and high cholesterol diet.

RESULTS

In vitro, SPION-DEXA were well-tolerated by endothelial cells. SPION-DEXA were internalized by human peripheral blood mononuclear cells and induced CD163 expression comparable with the free drug. In vivo, magnetic targeting of SPIONs to abdominal aorta was confirmed by histology. Upon vascular injury followed by high-cholesterol diet, early administration of SPION-DEXA enhanced the inflammatory burden in the plaques. Increased macrophage content and larger intima- media thickness were observed in animals treated with SPION-DEXA compared with controls. In advanced atherosclerosis, no beneficial effect of local glucocorticoid therapy was detectable.

CONCLUSION

Magnetic drug targeting represents an efficient platform to deliver drugs to diseased arteries in vivo. However, targeting of vascular injury in the lipid-rich environment using dexamethasone-conjugated SPIONs may cause accelerated inflammatory response.

Impaired Vascular Function in Sarcoidosis Patients

A common feature of sarcoidosis and atherosclerosis is a chronic systemic inflammatory reaction. Our hypothesis was that sarcoidosis may negatively influence the vessel status. We addressed the issue by examining preatherosclerotic vascular alternations using an ultrasound-based speckle-tracking method in 72 sarcoidosis patients and 15 matched controls. To find potential factors which may have a deleterious influence on arterial performance, different subgroups of sarcoidosis, such as sarcoidosis with or without cortisone therapy, pulmonary sarcoidosis in early and advanced stages, pulmonary sarcoidosis alone or combined with extrapulmonary sarcoidosis, and sarcoidosis with or without elevated blood levels of angiotensin converting enzyme (ACE)/soluble interleukin 2 receptor (sIL-2R) were investigated. We found in the general collective of sarcoidosis patients that circumferential strain (2.68 ± 0.19%), circumferential strain rate (0.21 ± 0.01 1/s), and radial displacement (0.10 ± 0.01 mm) were significantly decreased compared to controls (3.77 ± 0.35%, 0.28 ± 0.02 1/s, and 0.14 ± 0.02 mm, respectively). Vascular strains were more impaired in patients with cortisone therapy, pulmonary sarcoidosis in stages III-IV, and in pulmonary sarcoidosis accompanied by extrapulmonary involvement. The level of ACE/sIL-2R had no relevant influence on the angiological parameters. In conclusion, sarcoidosis is associated with increased vascular stiffness. Cortisone therapy and advanced stages of pulmonary sarcoidosis with extrapulmonary manifestations may account for the impaired vascular function in this patient collective.

Decreased OxLDL uptake and cholesterol efflux in THP1 cells elicited by cortisol and by cortisone through 11β-hydroxysteroid dehydrogenase type 1

BACKGROUND AND AIMS

Data about glucocorticoids role in the development of atherosclerosis are controversial showing different effects in human than in experimental animal models. Atherosclerosis is the result of a chronic inflammatory response to an injured endothelium where an uncontrolled uptake of OxLDL by macrophages triggers the development of foam cells, the main component of fatty streaks in atherosclerotic plaque. There are few data about the direct effect of glucocorticoids in macrophages of atherosclerotic plaque. The aim of the study was to elucidate the role of glucocorticoids in the development of foam cells in atherosclerosis initiation.

METHODS

For this purpose we used THP1 cells differentiated to macrophages with phorbol esters and incubated with OxLDL alone or with cortisol or cortisone. THP1 cells were also incubated with cortisone plus an inhibitor of 11β-hydroxysteroid dehydrogenase 1 (11βHSD1) activity to determine the role of this enzyme on glucocorticoid action in this process.

RESULTS

Ours results showed that cortisol and cortisone decreased significantly the inflammation promoted by OxLDL, and also diminished the expression of genes involved in influx and efflux of cholesterol resulting in a reduced lipid accumulation. Likewise cortisol and cortisone decreased 11βHSD1 expression in THP1 cells. The presence of the inhibitor of 11βHSD1 abolished all the effects elicited by cortisone.

CONCLUSION

Our results indicate a direct effect of glucocorticoids on macrophages braking atherosclerosis initiation, reducing pro-inflammatory markers and OxLDL uptake and cholesterol re-esterification, but also inhibiting cholesterol output. These effects appear to be mediated, at least in part, by 11βHSD1 activity.

Modulation of 11β-hydroxysteroid dehydrogenase as a strategy to reduce vascular inflammation

Atherosclerosis is a chronic inflammatory disease in which initial vascular damage leads to extensive macrophage and lymphocyte infiltration. Although acutely glucocorticoids suppress inflammation, chronic glucocorticoid excess worsens atherosclerosis, possibly by exacerbating systemic cardiovascular risk factors. However, glucocorticoid action within the lesion may reduce neointimal proliferation and inflammation. Glucocorticoid levels within cells do not necessarily reflect circulating levels due to pre-receptor metabolism by 11β-hydroxysteroid dehydrogenases (11β-HSDs). 11β-HSD2 converts active glucocorticoids into inert 11-keto forms. 11β-HSD1 catalyses the reverse reaction, regenerating active glucocorticoids. 11β-HSD2-deficiency/inhibition causes hypertension, whereas deficiency/inhibition of 11β-HSD1 generates a cardioprotective lipid profile and improves glycemic control. Importantly, 11β-HSD1-deficiency/inhibition is atheroprotective, whereas 11β-HSD2-deficiency accelerates atherosclerosis. These effects are largely independent of systemic risk factors, reflecting modulation of glucocorticoid action and inflammation within the vasculature. Here, we consider whether evidence linking the 11β-HSDs to vascular inflammation suggests these isozymes are potential therapeutic targets in vascular injury and atherosclerosis.

Both transient and continuous corticosterone excess inhibit atherosclerotic plaque formation in APOE*3-leiden.CETP mice

Introduction

The role of glucocorticoids in atherosclerosis development is not clearly established. Human studies show a clear association between glucocorticoid excess and cardiovascular disease, whereas most animal models indicate an inhibitory effect of glucocorticoids on atherosclerosis development. These animal models, however, neither reflect long-term glucocorticoid overexposure nor display human-like lipoprotein metabolism.

Aim

To investigate the effects of transient and continuous glucocorticoid excess on atherosclerosis development in a mouse model with human-like lipoprotein metabolism upon feeding a Western-type diet.

Methods

Pair-housed female APOE*3-Leiden.CETP (E3L.CETP) mice fed a Western-type containing 0.1% cholesterol for 20 weeks were given corticosterone (50 µg/ml) for either 5 (transient group) or 17 weeks (continuous group), or vehicle (control group) in the drinking water. At the end of the study, atherosclerosis severity, lesion area in the aortic root, the number of monocytes adhering to the endothelial wall and macrophage content of the plaque were measured.

Results

Corticosterone treatment increased body weight and food intake for the duration of the treatment and increased gonadal and subcutaneous white adipose tissue weight in transient group by +35% and +31%, and in the continuous group by +140% and 110%. Strikingly, both transient and continuous corticosterone treatment decreased total atherosclerotic lesion area by −39% without lowering plasma cholesterol levels. In addition, there was a decrease of −56% in macrophage content of the plaque with continuous corticosterone treatment, and a similar trend was present with the transient treatment.

Conclusion

Increased corticosterone exposure in mice with human-like lipoprotein metabolism has beneficial, long-lasting effects on atherosclerosis, but negatively affects body fat distribution by promoting fat accumulation in the long-term. This indicates that the increased atherosclerosis observed in humans in states of glucocorticoid excess may not be related to cortisol per se, but might be the result of complex indirect effects of cortisol.

Therapeutic manipulation of glucocorticoid metabolism in cardiovascular disease

The therapeutic potential for manipulation of glucocorticoid metabolism in cardiovascular disease was revolutionized by the recognition that access of glucocorticoids to their receptors is regulated in a tissue-specific manner by the isozymes of 11beta-hydroxysteroid dehydrogenase. Selective inhibitors of 11beta-hydroxysteroid dehydrogenase type 1 have been shown recently to ameliorate cardiovascular risk factors and inhibit the development of atherosclerosis. This article addresses the possibility that inhibition of 11beta-hydroxsteroid dehydrogenase type 1 activity in cells of the cardiovascular system contributes to this beneficial action. The link between glucocorticoids and cardiovascular disease is complex as glucocorticoid excess is linked with increased cardiovascular events but glucocorticoid administration can reduce atherogenesis and restenosis in animal models. There is considerable evidence that glucocorticoids can interact directly with cells of the cardiovascular system to alter their function and structure and the inflammatory response to injury. These actions may be regulated by glucocorticoid and/or mineralocorticoid receptors but are also dependent on the 11beta-hydroxysteroid dehydrogenases which may be expressed in cardiac, vascular (endothelial, smooth muscle) and inflammatory (macrophages, neutrophils) cells. The activity of 11beta-hydroxysteroid dehydrogenases in these cells is dependent upon differentiation state, the action of pro-inflammaotory cytokines and the influence of endogenous inhibitors (oxysterols, bile acids). Further investigations are required to clarify the link between glucocorticoid excess and cardiovascular events and to determine the mechanism through which glucocorticoid treatment inhibits atherosclerosis/restenosis. This will provide greater insights into the potential benefit of selective 11beta-hydroxysteroid dehydrogenase inhibitors in treatment of cardiovascular disease.

Glucocorticoid resistance caused by reduced expression of the glucocorticoid receptor in cells from human vascular lesions

Mechanisms that control the balance between cell proliferation and death are important in the development of vascular lesions. Rat primary smooth muscle cells were 80% inhibited by low microgram doses of hydrocortisone (HC) and 50% inhibited by nanogram concentrations of transforming growth factor-beta1 (TGF-beta1), although some lines acquired resistance in late passage. However, comparable doses of HC, or TGF-beta1, failed to inhibit most human lesion-derived cell (LDC) lines. In sensitive LDC, HC (10 microg/mL) inhibited proliferation by up to 50%, with obvious apoptosis in some lines, and TGF-beta1 inhibited proliferation by more than 90%. Collagen production, as measured by [3H]proline incorporation or RIA for type III pro-collagen, was either unaffected or increased in the LDCs by HC. These divergent responses between LDC lines were partially explained by the absence of the glucocorticoid receptor (GR) and heat shock protein 90 mRNA in 10 of 12 LDC lines, but the presence of the mineralocorticoid receptor and 11beta-hydroxysteroid dehydrogenase type II. Western blot analysis confirmed the absence of the GR protein in cells lacking GR mRNA. Immunohistochemistry of human carotid lesions showed high levels of GR in the tunica media, but large areas lacking GR in the fibrous lesion. Considering the absence of the GR in most lines, the effects of HC may be elicited through the mineralocorticoid receptor. Functional resistance to the antiproliferative and antifibrotic effects of HC may contribute to excessive wound repair in atherosclerosis and restenosis.

Corticosteroid agents inhibit proliferation of smooth muscle cells from human atherosclerotic arteries in vitro

We studied the in vitro effect of steroid agents on smooth muscle cells from human atherosclerotic arteries. Recent advances in the understanding of the biology of restenosis indicate that restenosis is predominantly caused by a multifactorial stimulation of smooth muscle cell proliferation. Primary stenosing plaque material of 24 patients (aged 63 +/- 14 years) and restenosing plaque material of 7 patients (aged 65 +/- 9 years) was selectively extracted from femoral arteries by the Simpson atherectomy device. Cells were isolated by enzymatic disaggregation and identified as smooth muscle cells by positive reaction with smooth muscle alpha-actin. The steroid agents prednisolone (0.0075-750 micrograms/ml), hydrocortisone (0.0125-1250 micrograms/ml), and dexamethasone (0.0004-40 micrograms/ml) were added to the cultures. Six days after seeding the cells were trypsinized and the cell number was measured by a cell counter. All three steroid agents exhibited a significant antiproliferative effect on smooth muscle cell proliferation. At high concentrations of hydrocortisone, cytoskeletal elements of smooth muscle cells such as actin, microtubules, and vimentin, were largely altered. Our data indicate that the proliferation of smooth muscle cells from human atherosclerotic arteries in vitro can be inhibited by steroid agents and thus may open the way for local post-angioplasty treatment strategies.

Experimental models of coronary artery restenosis

The study of potentially effective drug therapies and mechanical devices for the prevention of restenosis after percutaneous coronary revascularization has relied heavily on the use of experimental animal models. To date, greater than 50 experimental studies have been reported and have suggested that at least nine different classes of pharmacologic agents inhibit the intimal proliferative response to arterial injury. However, no pharmacologic intervention has yet been shown to reproducibly reduce the incidence of restenosis after coronary balloon angioplasty in humans. To identify the reasons for the apparent nonspecificity of the animal models and to determine which model should most reliably predict the efficacy of individual therapies in humans, the distinguishing characteristics of the experimental models were compared. Particular attention was paid to the size and morphologic structure of the treated artery, the susceptibility of the species to spontaneous and diet-induced arterial disease, the nature of the stimulus to intimal proliferation and several practical and logistic considerations. Finally, the reported efficacies of specific drug therapies in the respective animal models and in humans were compared. This review suggests that significant interspecies and occasionally intraspecies differences do exist among the respective animal models, particularly in the extent and composition of the neointimal thickening.(ABSTRACT TRUNCATED AT 250 WORDS)

A controlled trial of corticosteroids to prevent restenosis after coronary angioplasty. M-HEART Group

A multicenter, double-blind, placebo-controlled trial was conducted to determine if corticosteroids influence the development of restenosis after successful percutaneous transluminal coronary angioplasty (PTCA). Either placebo or 1.0 g methylprednisolone (steroid) was infused intravenously 2-24 hours before planned PTCA in 915 patients. The PTCA patient success rate was 87% (mean) in the eight centers. There were no differences in clinical or angiographic baseline variables between the two groups. End-point analysis (angiographic restenosis, death, recurrent ischemia necessitating early restudy, and coronary artery bypass graft surgery) showed that there was no significant difference comparing placebo- with steroid-treated patients. Angiographic restudy showed the lesion restenosis rate to be 39% (120 of 307 lesions) after placebo and 40% (117 of 291) after steroid treatment (p = NS). We conclude that pulse steroid pretreatment does not influence the overall restenosis rate after successful PTCA.

Evidence for an inverse relation between plasma triglyceride and aortic cholesterol in the coconut oil/cholesterol-fed rabbit

Rabbits fed a commercial chow diet containing 0.5% cholesterol and 14% coconut oil developed more severe hyperlipidemia and atherosclerosis than rabbits fed the same diet containing olive oil in place of coconut oil. Average plasma cholesterol was twice as high in the coconut oil/cholesterol-fed rabbits than in olive oil/cholesterol-fed rabbits. Final plasma triglycerides, although highly variable, were approx. 20-fold higher than basal plasma triglyceride in coconut oil/cholesterol-fed rabbits; plasma triglyceride in olive oil/cholesterol-fed rabbits remained unchanged throughout the study period. In coconut oil/cholesterol-fed rabbits, a direct relationship between plasma triglyceride and aortic cholesterol was not found. Plasma cholesterol and aortic cholesterol were also not correlated at a statistically significant level (r = 0.26, P greater than 0.25). However, when both plasma cholesterol and triglyceride were simultaneously introduced as predictors of aortic cholesterol, the correlation between these plasma lipids and aortic cholesterol became highly significant (r = 0.64, P less than 0.02). Aortic cholesterol increased in proportion to plasma cholesterol concentrations but appeared to be inversely related to plasma triglyceride levels.

Inhibition by methylprednisolone treatment of the aortic mineral accumulation in rabbits with chronic renal failure

The effect of methylprednisolone treatment on the mineral accumulation in the rabbit aorta during chronic renal failure (CRF) was investigated. Groups of rabbits with surgically induced CRF and sham operated controls were treated for 14 weeks with 0.40 mg of methylprednisolone per day and compared to corresponding groups receiving placebo. After sacrifice the thoracic aorta was excised and divided into an inner intima-media and an outer media layer before determination of the content of cholesterol and minerals. The surface area and wet weight of both layers were significantly increased in the CRF groups but methylprednisolone treatment had no effect on these parameters. Neither CRF nor methylprednisolone caused significant changes of the cholesterol content of the intima-media. Methylprednisolone treated CRF rabbits had a significantly decreased mineral content of the intima-media layer compared to CRF rabbits receiving placebo although the treatment caused no significant changes in the serum concentrations of calcium and phosphate. In rabbits with normal renal function a similar effect could not be demonstrated.

Effect of chronic renal failure and methylprednisolone treatment on the uptake of labelled plasma cholesterol into the aorta of normocholesterolemic rabbits

The effects of chronic renal failure (CRF) and corticosteroid treatment on the aortic uptake of labelled free and esterified cholesterol (FC and EC) were investigated in normocholesterolemic rabbits. Methylprednisolone, 0.4 mg/day, or placebo was administered for 14 weeks to rabbits with normal renal function and with CRF. Then [3H]- and [14C]cholesterol were administered intravenously and orally, respectively. The radioactivity levels of FC and EC in plasma were measured at regular intervals. After 48 h the accumulation of 3H and 14C radioactivity of FC and EC in the intima-media of the thoracic aorta was determined. An aortic uptake coefficient was calculated by dividing the tissue radioactivity (dpm/cm2/h) by the mean plasma radioactivity (dpm/ml). The mean uptake coefficient of EC in normal rabbits was 6 nl/cm2/h, the value for FC being 180 nl/cm2/h. In normal rabbits treated with methylprednisolone the uptake coefficients of both FC and EC were significantly decreased to about 50% of the values in normal rabbits receiving placebo. A similar significant decrease in the uptake coefficients was found in the CRF rabbits receiving placebo. No further decrease was observed in the CRF rabbits treated with methylprednisolone. The cholesterol content of the aortic intima-media was significantly decreased only in CRF rabbits on methylprednisolone treatment. The results do not indicate an acceleration of uremic arterial disease by steroid treatment in the rabbit.

Effects of rat adrenal homogenate on induction of atherosclerosis in cholesterol-fed rabbits

Virgin male Sprague-Dawley rats are resistant to atheroma formation. An adrenal homogenate from such rats delayed the increase in serum cholesterol concentrations in cholesterol-fed New Zealand white rabbits. More importantly, aortic atherosclerosis was markedly reduced when compared to a similar population fed cholesterol without adrenal homogenate for 14 weeks. The nature of the active constituent in this homogenate and its mode of action are unknown.

Cortisol and lysosomal stability in normal and atheromatous rats

The effect of cortisol on lysosomal stability has been studied in rats fed atherogenic and normal diets. beta-Glucuronidase has been taken as a lysosomal marker enzyme. Cortisol did not significantly alter total lysosomal enzyme activity in the liver or aorta or the activity present in the hepatic nuclear fraction. However, the hormone significantly increased activity in the intact lysosome and decreased soluble activity. The ratio of soluble activity (released from the lysosomes) to activity present in the intact lysosome showed that hepatic lysosomal stability was significantly increased in rats on cortisol. Cortisol tends to restore the decreased stability observed in atheromatous rats back to that in normal rats. The rate of release of enzyme from hepatic and aortic lysosomes was reduced by cortisol in both normal and atheromatous rats. Activity of serum lysosomal enzyme was also significantly lower in rats receiving cortisol. Cortisol subsequently added in vitro after the animals had been fed a normal or an atherogenic diet caused a significant in vitro decrease in the amount of enzyme released from hepatic lysosomes. The in vitro release of enzyme from lysosomes in normal rat liver progressively fell with increasing concentration of cortisol form 10(-5)--10(-4) M. Further increase in concentration up to 5 X 10(-4) M did not significantly alter enzyme release. Since cortisol was administered as its hemisuccinate the effect of succinate on lysosomal stability was also studied. It stabilized lysosomes, but the effect was much less than with cortisol.

Cell proliferation in the atherosclerotic plaques of cholesterol-fed rabbits. Part 3. Histological and radioautographic observations on glucocorticoids-treated rabbits

Tritiated thymidine radioautography was employed to study the effect of cortisol and other glucocorticoids on cellular proliferation in the aorta and pulmonary artery of rabbits with cholesterol atherosclerosis. Labelled cell counts showed that glucocorticoids, even after one day and at a relatively low dose, decrease sharply the deoxyribonucleic acid synthesis in the intimal plaques. The hormonal influence on [3H]thymidine uptake seems to be a dose-dependent process. The relative potency of these steroids in inhibiting DNA synthesis in the plaques parallels closely their anti-inflammatory effectiveness. Conversely mineralocorticoids, including aldosterone and deoxycorticosterone, increase the rate of DNA synthesis in the plaques. It is concluded that the antiatherogenic effect of glucocorticoids on cholesterol-fed rabbits may be due, at least partly, to the inhibitory effect of these steroids on the DNA synthesis of the cellular components of the intimal plaques.

Effects of methyl prednisolone and colchicine on the development of aortic atherosclerosis in swine

The effect of methyl prednisolone and colchicine on the development of both the early proliferative and advanced atherosclerotic lesion in swine aorta was studied. In order to accelerate the development of atherosclerosis, the abdominal aortic endothelium was partially denuded by a balloon before the animals were placed on either a moderate or severe hypercholesterolemic diet. Neither drug in either dietary group inhibited the development of atherosclerosis. Swine receiving methyl prednisolone and severe hypercholesterolemic diet actually had a significantly greater number of the advanced necrotic lesions and more arterial calcification than the group receiving the atherogenic diet alone. In addition, the thoracic aorta of swine receiving the moderate hypercholesterolemic diet and methyl prednisolone showed larger amounts of lipid than did the non-drug fed control group. In swine receiving the moderate hypercholesterolemic diet, methyl prednisolone significantly raised serum cholesterol levels. Colchicine only slightly worsened the atherosclerosis in swine aorta and had no effect on serum cholesterol levels.

Study of drugs affecting cholesterol-induced atherosclerosis in rabbits

1. Effects of various drugs on cholesterol-induced atherosclerosis in rabbits during the progression phase have been studied. The drugs tested are antimetabolites (mercaptopurine, hydroxyurea), surface active agents (sodiumdodecyl sulfate), inhibitor of adrenocoritcal steroid synthesis (o, p'-DDD), lysosome stablizers (chloroquine, acetylsalicylic acid) with antihistaminic (chlorpheniramine) and cholesterol binder (nystatin). 2. Mercaptopurine treatment showed marekd reduction in both atherosclerotic lesions and cholesterol concentrations of the serum and aorta. 3. Hydroxyurea reduced both the aortic cholesterol concentration and the lesions, but the serum cholesterol concentration remained high. 4. Sodiumdodecyl sulfate and o, o'-DDD showed slight inhibition of the development of atherosclerosis. 5. Pyridinocarbamate showed a slight beneficial effect on the prevention of atherosclerosis only when it was administered prior to the meal. 6. Nystatin, chloroquine and acetylsalicylic acid + chlorpheniramine showed little effect.

The effect of renal hypertension on cholesterol atherosclerosis in cortisone-treated rabbits

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Nodular and fatty glomerular lesions in rabbits on cortisone

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