Diabetic retinopathy is the most feared complication for those with diabetes. Although visible vascular pathology traditionally defines the management of this condition, it is now recognised that a range of cellular changes occur in the retina from an early stage of diabetes. One of the most significant functional changes that occurs in those with diabetes is a loss of vasoregulation in response to changes in neural activity. There are several retinal cell types that are critical for mediating so-called neurovascular coupling, including Müller cells, microglia and pericytes. Although there is a great deal of evidence that suggests that Müller cells are integral to regulating the vasculature, they only modulate part of the vascular tree, highlighting the complexity of vasoregulation within the retina. Recent studies suggest that retinal immune cells, microglia, play an important role in mediating vasoconstriction. Importantly, retinal microglia contact both the vasculature and neural synapses and induce vasoconstriction in response to neurally expressed chemokines such as fractalkine. This microglial-dependent regulation occurs via the vasomediator angiotensinogen. Diabetes alters the way microglia regulate the retinal vasculature, by increasing angiotensinogen expression, causing capillary vasoconstriction and contributing to a loss of vascular reactivity to physiological signals. This article summarises recent studies showing changes in vascular regulation during diabetes, the potential mechanisms by which this occurs and the significance of these early changes to the progression of diabetic retinopathy.

BACKGROUND: It is thought that genetic factors may play an important role in the development of coronary artery disease (CAD). Several studies report that AGT polymorphism is implicated in CAD susceptibility, but these results contradict those of the other studies with the associations being unclear in the Eastern Asian population. Therefore, meta-analysis was performed to evaluate this relationship.
METHODS: Publication databases were used to search for eligible relevant studies and valid data were extracted from studies meeting the inclusion criteria. Subsequently, odds ratios (ORs) with 95 % confidence intervals (CIs), were used to assess the strength of the association between AGT polymorphism and CAD risk.
RESULTS: Seven eligible studies published only in English were included in the present meta-analysis. In the Eastern Asian population, CAD susceptibility was shown to be related to AGT M235T under the heterozygote model (OR = 0.19). Stratified analysis indicated there was a significant relationship between AGT M235T and CAD risk in China under allelic (OR = 1.34), dominant (OR = 1.43), and heterozygote (OR = 1.62) models. The results showed that the T174M polymorphism was significantly associated with CAD risk in recessive (OR = 2.28) and homozygote (OR = 2.37) models in the Eastern Asian population.
CONCLUSIONS: In the Eastern Asian population, especially the Chinese, the M235T of AGT is associated with CAD susceptibility. The T174M polymorphisms were associated with CAD risk in the Eastern Asian population.

OBJECTIVE:  To describe the effects of combined oral contraceptives (COC) on the renin-angiotensin-aldosterone system (RAAS).
METHODS:  This is a systematic review according to the criteria of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), registered in PROSPERO under the ID: CRD42020200019. Searches were performed between August 2020 and December 2021, in the following databases: Medline via Pubmed, Cochrane Central Library, Scientific Electronic Library Online, and Latin American and Caribbean Literature in Health Sciences via Virtual Health Library. The effects of the combined oral contraceptive on plasma renin activity values, plasma renin values, angiotensinogen values- also known as plasma renin substrate- angiotensin, and/or aldosterone values.
METHODS:  A total of 877 studies were selected and, of these, 10 articles met the eligibility criteria and were included in this review.
METHODS:  Data were combined through qualitative synthesis and included in a spreadsheet previously prepared by the authors.
RESULTS:  The collected samples ranged from 18 to 137 participants, totaling 501 women aged between 18 and 49 years throughout all studies. The studies showed increased activity of plasma renin, plasma renin substrate, angiotensin II, and aldosterone in this population.
CONCLUSIONS:  The findings of this study suggest that the COC promotes greater activation of the RAAS. Supporting the idea that its use is related to an increased risk of cardiovascular events, including systemic arterial hypertension.
OBJECTIVE:  Descrever os efeitos do contraceptivo oral combinado (COC) no sistema renina-angiotensina-aldosterona (SRAA).
UNASSIGNED:  Trata-se de uma revisão sistemática de acordo com os critérios do Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), registrada no PROSPERO sob ID: CRD42020200019. As buscas foram realizadas entre agosto de 2020 e dezembro de 2021 nas bases de dados: Medline via Pubmed, Biblioteca Cochrane Central, Scientific Electronic Library Online, e Literatura Latino-americana e do Caribe em Ciências da Saúde via Biblioteca Virtual em Saúde. Consultado os artigos sobre os efeitos do contraceptivo oral combinado nos valores da atividade da renina plasmática, valores plasmáticos da renina, valores do angiotensinogênio – também conhecido como substrato da renina plasmática –, valores da angiotensina e/ou aldosterona. SELEçãO DOS ESTUDOS:  Foram selecionados 877 estudos e, destes, 10 artigos preencheram os critérios de elegibilidade e foram incluídos nesta revisão.
UNASSIGNED:  Os dados foram combinados por meio de síntese qualitativa e inclusos em uma planilha elaborada previamente pelos autores. SíNTESE DOS DADOS:  As amostras coletadas variavam entre 18 e 137 participantes, totalizando 501 mulheres com idade entre 18 e 49 anos em todos os estudos. Os estudos apresentaram aumento da atividade da renina plasmática, do substrato da renina plasmática, da angiotensina II e da aldosterona nessa população. CONCLUSãO:  Os achados deste estudo sugerem que o COC promove maior ativação do SRAA. Apoiando a ideia de que o seu uso esteja relacionado ao aumento do risco de eventos cardiovasculares, incluindo a hipertensão arterial sistêmica.

Chronic kidney disease (CKD) is defined by abnormalities in kidney structure and/or function present for more than 3 months. Worldwide, both the incidence and prevalence rates of CKD are increasing. The renin-angiotensin-aldosterone system (RAAS) regulates fluid and electrolyte balance through the kidney. RAAS activation is associated with hypertension, which is directly implicated in causation and progression of CKD. RAAS blockade, using drugs targeting individual RAAS mediators and receptors, has proven to be renoprotective.
To assess genomic variants present within RAAS genes, ACE, ACE2, AGT, AGTR1, AGTR2 and REN, for association with CKD.
A systematic review and meta-analysis of observational research was performed to evaluate the RAAS gene polymorphisms in CKD using both PubMed and Web of Science databases with publication date between the inception of each database and 31 December 2018. Eligible articles included case-control studies of a defined kidney disease and included genotype counts.
Any paper was removed from the analysis if it was not written in English or Spanish, was a non-human study, was a paediatric study, was not a case-control study, did not have a renal disease phenotype, did not include data for the genes, was a gene expression-based study or had a pharmaceutical drug focus.
A total of 3531 studies were identified, 114 of which met the inclusion criteria. Genetic variants reported in at least three independent publications for populations with the same ethnicity were determined and quantitative analyses performed. Three variants returned significant results in populations with different ethnicities at p<0.05: ACE insertion, AGT rs699-T allele and AGTR1 rs5186-A allele; each variant was associated with a reduced risk of CKD development.
Further biological pathway and functional analyses of the RAAS gene polymorphisms will help define how variation in components of the RAAS pathway contributes to CKD.

Chymase is primarily found in mast cells (MCs), fibroblasts, and vascular endothelial cells. MC chymase is released into the extracellular interstitium in response to inflammatory signals, tissue injury, and cellular stress. Among many functions, chymase is a major extravascular source for angiotensin II (Ang II) generation. Several recent pre-clinical and a few clinical studies point to the relatively unrecognized fact that chymase inhibition may have significant therapeutic advantages over other treatments in halting progression of cardiac and vascular disease.
The present review covers patent literature on chymase inhibitors for the treatment of cardiac diseases registered between 2010 and 2018.
Increase in cardiac MC number in various cardiac diseases has been found in pathological tissues of human and experimental animals. Meta-analysis data from large clinical trials employing angiotensin-converting enzyme (ACE) inhibitors show a relatively small risk reduction of clinical cardiovascular endpoints. The disconnect between the expected benefit associated with Ang II blockade of synthesis or activity underscores a greater participation of chymase compared to ACE in forming Ang II in humans. Emerging literature and a reconsideration of previous studies provide lucid arguments to reconsider chymase as a primary Ang II forming enzyme in human heart and vasculature.

In angiotensin (Ang)-II-dependent hypertension, collecting duct renin synthesis and secretion are stimulated despite suppression of juxtaglomerular (JG) renin. This effect is mediated by Ang II type 1 (AT1) receptor independent of blood pressure. Although the regulation of JG renin is known, the mechanisms by which renin is regulated in the collecting duct are not completely understood. The presence of renin activity in the collecting duct may provide a pathway for intratubular Ang II formation since angiotensinogen substrate and angiotensin converting enzyme are present in the distal nephron. The recently named new member of the renin-angiotensin system (RAS), the (pro)renin receptor [(P)RR], is able to bind renin and the inactive prorenin, thus enhancing renin activity and fully activating prorenin. We have demonstrated that renin and (P)RR are augmented in renal tissues from rats infused with Ang II and during sodium depletion, suggesting a physiological role in intrarenal RAS activation. Importantly, (P)RR activation also causes activation of intracellular pathways associated with increased cyclooxygenase 2 expression and induction of profibrotic genes. In addition, renin and (P)RR are upregulated by Ang II in collecting duct cells. Although the mechanisms involved in their regulation are still under study, they seem to be dependent on the intrarenal RAS activation. The complexities of the mechanisms of stimulation also depend on cyclooxygenase 2 and sodium depletion. Our data suggest that renin and (P)RR can interact to increase intratubular Ang II formation and the activation of profibrotic genes in renal collecting duct cells. Both pathways may have a critical role in the development of hypertension and renal disease.

OBJECTIVE: To evaluate the influence of the angiotensinogen (AGT) gene on the individual predisposition to pre-eclampsia, we screened the AGT gene for pathogenic mutations and an association of identified polymorphisms in German women with pre-eclampsia.
METHODS: The study population consisted of 67 German primi- and multigravid patients with pre-eclampsia or superimposed pre-eclampsia and 100 controls with uncomplicated singleton pregnancies. The initial screening for mutations was carried out in a subgroup of pre-eclampsia patients by single-strand conformation polymorphism analysis and direct sequencing.
RESULTS: Fifteen single nucleotide polymorphisms (SNPs) were detected, of which 14 had been described before. Allelic frequencies of the detected SNPs were estimated in the total study population. Only the promoter polymorphism g.-570C>T was associated with pre-eclampsia (p = 0.038) but after adjustment for multiple testing p was >0.05. The well-known M268T [M235T] polymorphism was not associated with pre-eclampsia.
CONCLUSIONS: Our results do not indicate an association of the AGT gene with pre-eclampsia. Data from previously published studies are conflicting: positive results were reported in at least 4 studies, negative results in 10 studies. A possible influence, if existing at all, is obviously very small. AGT therefore does not play a major role in the etiology of pre-eclampsia.

The extent of blood pressure lowering by anti-hypertensive agents is difficult to predict for individual patients, even when evaluated in the context of biochemical or demographic information. Genetic predictors (mainly single nucleotide polymorphisms, SNPs) have been the focus of several recent studies and are gaining much attention. We have conducted a literature search for studies in which the lowering of ambient blood pressure by specific drugs or drug classes in humans was related to specific genotypes. Twenty-eight studies were identified, of which six had a single-dose design, and the remaining 22 studied drug effects after more than 4 weeks of drug administration. Virtually all were association studies. Prospective trials that compared the prognostic value of genetic methods to routine clinical practice were not identified. Almost all studies used a candidate-gene design, usually with a very small number of SNPs (typically one). Gene-gene and gene-environment interactions were studied only rarely. Only one study targeted genes involved in drug metabolism. Most candidate-genes were part of the renin-angiotensin system. By far the most extensively studied has been the angiotensin-converting enzyme insertion/deletion polymorphism (15 studies) but, to date, no clear picture has emerged for this or other genetic variants. Thus, the potential for utility of genetic characterization of individual patients as a predictor of anti-hypertensive response has yet to be realized.

Estradiol-intranasal is a nasal spray formulation containing an aqueous solution of 17beta-estradiol that has a unique pulse-like pharmacokinetic profile. In a well designed, placebo-controlled trial estradiol-intranasal 200 to 400 microg/day significantly reduced the incidence and severity of climacteric symptoms in women with moderate to severe menopausal symptoms after 4 and 12 weeks\' treatment. The efficacy of estradiol-intranasal 300 microg/day was similar to that of oral estradiol 2 mg/day in this and another double-blind placebo-controlled trial. This equivalent efficacy was maintained in a subgroup of women with initially severe symptoms, and in smokers. Reductions in the incidence of atrophic vaginal mucosa and genitourinary symptoms and increases in the karyopyknotic index achieved with estradiol-intranasal 300 microg/day were also similar to those observed with oral estradiol 2 mg/day. Assessments of the effects of estradiol-intranasal on the complications of menopause (increased risk of cardiovascular disease and osteoporosis) are ongoing; however, estradiol-intranasal (sequentially combined with a progestogen) produced significant beneficial effects on some lipid parameters and on markers of bone resorption and formation, and bone mineral density in postmenopausal women. Estradiol-intranasal had no significant effects on serum levels of most of the assessed haemostatic factors, or on angiotensinogen or insulin levels. Estradiol-intranasal 100 to 600 microg/day was generally well tolerated in clinical trials and most adverse events were mild to moderate. The most commonly reported events were nasal symptoms and mastalgia. There was no evidence of endometrial hyperplasia with up to 1 year\'s treatment with estradiol-intranasal 300 microg/day combined with a progestogen. The incidence of mastalgia and withdrawal or breakthrough bleeding was lower with estradiol-intranasal 300 microg/day than with oral estradiol 2 mg/day (both administered with a progestogen) in one trial. In another trial, the incidence of mastalgia was lower with estradiol-intranasal 300 microg/day than with estradiol transdermal 50 microg (both administered with a progestogen). However, the overall incidence of adverse events was similar between the two treatments in this trial.
CONCLUSIONS: Estradiol-intranasal 200 to 400 microg/day (optimal initiating dose 300 microg/day) reduces the incidence and severity of menopausal climacteric symptoms and has a good tolerability profile. Thus, evidence to date suggests that estradiol-intranasal is a useful treatment option for menopausal symptoms.

Extensive animal studies and a growing number of human clinical trials have now definitively demonstrated the central role of the renin-angiotensin-aldosterone system in the expression and modulation of cardiovascular disease. In contrast to the original hypothesis, the benefits of angiotensin antagonism do not emanate from the antihypertensive effect alone. Subsequent extensive investigations of angiotensin blockade suggest that the benefits of this approach may also result from the pharmacologic alteration of endothelial cell function and the ensuing changes in the biology of the vasculature. The more recent availability of direct antagonists of the AT(1) angiotensin receptor has introduced an element of doubt into this realm of clinical decision making. The receptor antagonists and the more widely studied converting-enzyme inhibitors share many endpoint attributes. Nevertheless, the partially overlapping mechanisms of action for the two classes of angiotensin antagonists confer distinct pharmacologic properties, including side effect profiles, mechanisms of action, and theoretic salutary effects upon the expression of cardiovascular disease. The current review will attempt to contrast the biology of angiotensin converting-enzyme inhibition with angiotensin II receptor antagonism. A discussion of the differential effects of these drug classes on endothelial cell function and on the modulation of vascular disease will be utilized to provide a theoretic framework for clinical decision making and therapeutics.