1. Improved method for surgical induction of chronic hypertension in mice
Tom Skaria, Mostafa A Aboouf, Johannes Vogel Biol Open. 2022 Jul 15;11(7):bio059164. doi: 10.1242/bio.059164. Epub 2022 Jul 5.
Chronic hypertension can be induced in mice by one-kidney one-clip (1K1C) or two-kidney one-clip surgery, transgenic overexpression of angiotensinogen and renin, administration of deoxycorticosterone acetate-salt, supplying Nitro-L-arginine methyl-ester in the drinking water and Angiotensin-II infusion. Although each model has its own pros and cons, selection of a model that mimics human hypertensive disease accurately is essential to ensure rigor and reproducibility in hypertension research. 1K1C mice represent an efficient, budget-friendly, and translationally capable model; however, their use in preclinical research has remained largely hindered due to concerns about potential technical complexity and lack of reported information regarding procedure-related mortality rates. Here, we describe in detail an improved version of the 1K1C surgery in mice that has zero intraoperative mortality and excellent survival rates in a long-term setting and permits the development of stable chronic hypertension and its target organ complications. Key to this outcome is unilateral nephrectomy 1 week after renal artery clipping to decelerate the blood pressure (BP) increase, which allows the organism to adapt better to the BP rise. The technical and animal welfare improvements presented here may promote the acceptance of the 1K1C model.
2. Clinical Phenotypes of Heart Failure With Preserved Ejection Fraction to Select Preclinical Animal Models
Willem B van Ham, et al. JACC Basic Transl Sci. 2022 May 25;7(8):844-857. doi: 10.1016/j.jacbts.2021.12.009. eCollection 2022 Aug.
At least one-half of the growing heart failure population consists of heart failure with preserved ejection fraction (HFpEF). The limited therapeutic options, the complexity of the syndrome, and many related comorbidities emphasize the need for adequate experimental animal models to study the etiology of HFpEF, as well as its comorbidities and pathophysiological changes. The strengths and weaknesses of available animal models have been reviewed extensively with the general consensus that a "1-size-fits-all" model does not exist, because no uniform HFpEF patient exists. In fact, HFpEF patients have been categorized into HFpEF phenogroups based on comorbidities and symptoms. In this review, we therefore study which animal model is best suited to study the different phenogroups-to improve model selection and refinement of animal research. Based on the published data, we extrapolated human HFpEF phenogroups into 3 animal phenogroups (containing small and large animals) based on reports and definitions of the authors: animal models with high (cardiac) age (phenogroup aging); animal models focusing on hypertension and kidney dysfunction (phenogroup hypertension/kidney failure); and models with hypertension, obesity, and type 2 diabetes mellitus (phenogroup cardiometabolic syndrome). We subsequently evaluated characteristics of HFpEF, such as left ventricular diastolic dysfunction parameters, systemic inflammation, cardiac fibrosis, and sex-specificity in the different models. Finally, we scored these parameters concluded how to best apply these models. Based on our findings, we propose an easy-to-use classification for future animal research based on clinical phenogroups of interest.
3. Effect of antihypertensive treatment and N omega-nitro-L-arginine methyl ester on cardiovascular structure in deoxycorticosterone acetate-salt hypertensive rats
J S Li, P Sventek, E L Schiffrin J Hypertens. 1996 Nov;14(11):1331-9. doi: 10.1097/00004872-199611000-00012.
Background: Deoxycorticosterone acetate (DOCA)-salt hypertensive rats exhibit a very severe degree of cardiovascular hypertrophy, which may in part be mediated by overexpression of the endothelin-1 gene. Objective: To examine the effects of the angiotensin I converting enzyme inhibitor cilazapril and of the calcium channel antagonist mibefradil, both of which may affect potential mechanisms responsible for hypertrophy of cardiovascular structures, and that of the nitric oxide synthase inhibitor N omega-nitro-L-arginine methyl ester (L-NAME), which may exert a paradoxical inhibitory effect on cardiovascular growth, on the severe cardiovascular hypertrophy of DOCA-salt hypertensive rats and on arterial expression of the endothelin-1 gene. Methods: Small-artery structure was examined on a wire myograph and endothelin-1 messenger RNA (mRNA) was quantified by Northern blot analysis. Results: Cilazapril did not affect blood pressure, cardiovascular structure or the increased abundance of endothelin mRNA of DOCA-salt hypertensive rats. Mibefradil treatment resulted in lower blood pressure, reduced cardiac hypertrophy, near-normal structure of conduit and small arteries and lower endothelin-1 mRNA abundance. L-NAME treatment resulted in higher blood pressure and increased severity of conduit artery hypertrophy, but reduced cardiac and small artery hypertrophy, and enhanced aortic endothelin-1 mRNA. Conclusion: These results suggest that the renin-angiotensin system does not play a role in cardiovascular hypertrophy in DOCA-salt hypertensive rats, which is not unexpected since plasma renin is suppressed in these rats. Calcium channel blockade may interfere with mechanisms underlying vascular hypertrophy in this model via blockade of calcium entry or by reducing vascular endothelin-1 gene expression when the blood pressure is lowered. L-NAME has been shown to exert a growth-inhibitory effect on small arteries and on the heart despite increasing blood pressure, probably independently from its ability to inhibit nitric oxide synthase, the latter of which is presumably involved in the blood pressure rise induced.
