Influence of Renin-Angiotensin System Inhibitors on Lower-Respiratory Tract Infections in Type 2 Diabetes: The Fremantle Diabetes Study Phase II

Beyond blood pressure, fluid and electrolyte homeostasis - Role of the renin angiotensin aldosterone system in the interplay between metabolic diseases and breast cancer

The classical renin angiotensin aldosterone system (RAAS), as well as the recently described counter-regulatory or non-canonical RAAS have been well characterized for their role in cardiovascular homeostasis. Moreover, extensive research has been conducted over the past decades on both paracrine and the endocrine roles of local RAAS in various metabolic regulations and in chronic diseases. Clinical evidence from patients on RAAS blockers as well as pre-clinical studies using rodent models of genetic manipulations of RAAS genes documented that this system may play important roles in the interplay between metabolic diseases and cancer, namely breast cancer. Some of these studies suggest potential therapeutic applications and repurposing of RAAS inhibitors for these diseases. In this review, we discuss the mechanisms by which RAAS is involved in the pathogenesis of metabolic diseases such as obesity and type-2 diabetes as well as the role of this system in the initiation, expansion and/or progression of breast cancer, especially in the context of metabolic diseases.

Calcitriol attenuates poly(I:C)-induced lung injury in obese mice via modulating toll-like receptor 3- and renin-angiotensin system-associated signal pathways

This study investigated the effects of calcitriol on polyinosinic-polycytidylic acid (poly(I:C))-induced acute lung injury (ALI) and its association with Toll-like receptor 3 (TLR3) and renin-angiotensin system (RAS) signal pathways in obese mice. Normal mice were fed a high-fat diet to induce obesity. Obese mice were divided into four groups: SS group, intratracheally instilled with saline and intravenous (IV) saline injection via tail vein; SD group, instilled with saline and IV calcitriol injection; PS group, instilled with poly(I:C) and IV saline injection; and PD group, instilled with poly(I:C) and IV calcitriol injection. All mice were sacrificed 12 or 24 h after poly(I:C) stimulation. The results showed that poly(I:C) instillation led to increased production of systemic inflammatory cytokines. In the lungs, the population of macrophages decreased, while more neutrophils were recruited. TLR3-associated genes including IRF3, nuclear factor-κB, interferon-β and phosphorylated IRF3 expression levels, were upregulated. The RAS-associated AT1R and ACE2 protein levels increased, whereas AT2R, Ang(1-7), and MasR levels decreased. Also, reduced tight junction (TJ) proteins and elevated lipid peroxide levels were observed 24 h after poly(I:C) stimulation. Compared to the PS group, the PD group exhibited reduced systemic and lung inflammatory cytokine levels, increased macrophage while decreased neutrophil percentages, downregulated TLR3-associated genes and phosphorylated IRF3, and polarized toward the RAS-AT2R/Ang(1-7)/MasR pathway in the lungs. Higher lung TJ levels and lower injury scores were also noted. These findings suggest that calcitriol treatment after poly(I:C) instillation alleviated ALI in obese mice possibly by downregulating TLR3 expression and tending toward the RAS-associated anti-inflammatory pathway.

A Comprehensive Systematic Review of Data Linkage Publications on Diabetes in Australia

Aims

Our study aimed to identify the common themes, knowledge gaps and to evaluate the quality of data linkage research on diabetes in Australia.

Methods

This systematic review was developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (the PRISMA Statement). Six biomedical databases and the Australian Population Health Research Network (PHRN) website were searched. A narrative synthesis was conducted to comprehensively identify the common themes and knowledge gaps. The guidelines for studies involving data linkage were used to appraise methodological quality of included studies.

Results

After screening and hand-searching, 118 studies were included in the final analysis. Data linkage publications confirmed negative health outcomes in people with diabetes, reported risk factors for diabetes and its complications, and found an inverse association between primary care use and hospitalization. Linked data were used to validate data sources and diabetes instruments. There were limited publications investigating healthcare expenditure and adverse drug reactions (ADRs) in people with diabetes. Regarding methodological assessment, important information about the linkage performed was under-reported in included studies.

Conclusions

In the future, more up to date data linkage research addressing costs of diabetes and its complications in a contemporary Australian setting, as well as research assessing ADRs of recently approved antidiabetic medications, are required.

Time-varying risk associations of renin angiotensin system inhibitors with pneumonia and related deaths in a cohort of 252,616 patients with diabetes (2002-2019)

AIMS

To evaluate the time-varying and cumulative risk associations of renin-angiotensin-system-inhibitors (RASi) with pneumonia and related deaths in people with diabetes.

METHODS

This was a prospective analysis with propensity-score overlap-weighting of a territory-wide cohort (n = 252,616, 1.7 million person-years) and a register-based cohort (n = 13,017, 0.1 million person-years) of patients with diabetes in Hong Kong. We compared risk of pneumonia and related death in new-users of angiotensin-converting-enzyme-inhibitor (ACEi) and angiotensin-receptor-blocker (ARBs) with non-RASi users and new-users of calcium-channel-blockers as active comparator.

RESULTS

Amongst 252,616 people with diabetes (99.3% type 2 diabetes) in the population-based cohort with a mean follow-up of 6.7 years, 73,161 were new-ACEi-only users; 20,907 new-ARBs-only users; 38,778 ACEi/ARBs users; and 119,770 never-ACEi/ARBs. Time-varying RASi exposure was associated with reduced risk of pneumonia (HR = 0.78, 95% CI: 0.75-0.82) and pneumonia-related death (HR = 0.49, 0.46-0.53). The respective HRs for ARBs-only were 0.70 (0.62-0.78) and 0.41 (0.33-0.52) and that of ACEi-only were 0.98 (0.91-1.05) and 0.77 (0.68-86). The attenuated risk association of RASi use was time-invariant for pneumonia (P = 0.340) and time-varying for related-death (P < 0.001) with prevention of 0.6 (0.2-0.9) and 1.4 (1.0-1.6) per-1000-person-years events and deaths, respectively.

CONCLUSIONS

Long-term use of RASi, notably ARBs, was associated with reduced risk of pneumonia and related deaths in Chinese people with diabetes.

Pathophysiology of COVID-19: Everywhere You Look You Will See ACE2!

Angiotensin converting enzyme 2 (ACE₂) seems to be a central actor in the pathophysiology of SARS-Cov-2 infection. First, it acts as the receptor for the virus and permits its attachment to cells expressing ACE₂. Second, the relative deficiency of ACE₂ during infection could be linked to several clinical features encountered during the disease, like ARDS and coagulation abnormalities. This study explores the strong link between ACE₂ and the majority of risk factors for the severe evolution of COVID-19. It seems that all these risks factors are linked to an increased level of ACE₂ and/or imbalance in ACE/ACE₂.

Angiotensin Receptor Blockers Are Not Just for Hypertension Anymore

Beyond blood pressure control, angiotensin receptor blockers reduce common injury mechanisms, decreasing excessive inflammation and protecting endothelial and mitochondrial function, insulin sensitivity, the coagulation cascade, immune responses, cerebrovascular flow, and cognition, properties useful to treat inflammatory, age-related, neurodegenerative, and metabolic disorders of many organs including brain and lung.

Candesartan could ameliorate the COVID-19 cytokine storm

BACKGROUND

Angiotensin receptor blockers (ARBs) reducing inflammation and protecting lung and brain function, could be of therapeutic efficacy in COVID-19 patients.

METHODS

Using GSEA, we compared our previous transcriptome analysis of neurons injured by glutamate and treated with the ARB Candesartan (GSE67036) with transcriptional signatures from SARS-CoV-2 infected primary human bronchial epithelial cells (NHBE) and lung postmortem (GSE147507), PBMC and BALF samples (CRA002390) from COVID-19 patients.

RESULTS

Hundreds of genes upregulated in SARS-CoV-2/COVID-19 transcriptomes were similarly upregulated by glutamate and normalized by Candesartan. Gene Ontology analysis revealed expression profiles with greatest significance and enrichment, including proinflammatory cytokine and chemokine activity, the NF-kappa B complex, alterations in innate and adaptive immunity, with many genes participating in the COVID-19 cytokine storm.

CONCLUSIONS

There are similar injury mechanisms in SARS-CoV-2 infection and neuronal injury, equally reduced by ARB treatment. This supports the hypothesis of a therapeutic role for ARBs, ameliorating the COVID-19 cytokine storm.

Renin-Angiotensin System: An Important Player in the Pathogenesis of Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is characterized by massive inflammation, increased vascular permeability and pulmonary edema. Mortality due to ARDS remains very high and even in the case of survival, acute lung injury can lead to pulmonary fibrosis. The renin-angiotensin system (RAS) plays a significant role in these processes. The activities of RAS molecules are subject to dynamic changes in response to an injury. Initially, increased levels of angiotensin (Ang) II and des-Arg⁹-bradykinin (DABK), are necessary for an effective defense. Later, augmented angiotensin converting enzyme (ACE) 2 activity supposedly helps to attenuate inflammation. Appropriate ACE2 activity might be decisive in preventing immune-induced damage and ensuring tissue repair. ACE2 has been identified as a common target for different pathogens. Some Coronaviruses, including SARS-CoV-2, also use ACE2 to infiltrate the cells. A number of questions remain unresolved. The importance of ACE2 shedding, associated with the release of soluble ACE2 and ADAM17-mediated activation of tumor necrosis factor-α (TNF-α)-signaling is unclear. The roles of other non-classical RAS-associated molecules, e.g., alamandine, Ang A or Ang 1-9, also deserve attention. In addition, the impact of established RAS-inhibiting drugs on the pulmonary RAS is to be elucidated. The unfavorable prognosis of ARDS and the lack of effective treatment urge the search for novel therapeutic strategies. In the context of the ongoing SARS-CoV-2 pandemic and considering the involvement of humoral disbalance in the pathogenesis of ARDS, targeting the renin-angiotensin system and reducing the pathogen's cell entry could be a promising therapeutic strategy in the struggle against COVID-19.