The Renin-Angiotensin-Aldosterone System (RAAS) Is One of the Effectors by Which Vascular Endothelial Growth Factor (VEGF)/Anti-VEGF Controls the Endothelial Cell Barrier

RAAS in diabetic retinopathy: mechanisms and therapies

Diabetic retinopathy (DR) is a complication of diabetes with a complex pathophysiology and multiple factors involved. Recently, it has been found that the upregulation of the renin-angiotensin-aldosterone system (RAAS) leads to overexpression of angiotensin II (Ang II), which induces oxidative stress, inflammation, and angiogenesis in the retina. Therefore, RAAS may be a promising therapeutic target in DR. Notably, RAAS inhibitors are often used in the treatment of hypertension. Still, the potential role and mechanism of DR must be further studied. In this review, we discuss and summarize the pathology and potential therapeutic goals of RAAS in DR.

Anticancer Potential of ACEIs/ARBs Administration in Colorectal Cancer

BACKGROUND

Colorectal cancer (CC) is the fourth most common type of cancer that causes illness and death. Medicines like ACE inhibitors and ARBs, usually used for heart problems, have shown they might help with the growth and development of CC.

INTRODUCTION

An analysis of ACE inhibitors and colon cancer is conducted in this comprehensive review. The main goal is to see how ACEIs/ARBs affect the chances of getting cancer and dying in patients with CC.

METHODS

A systematic literature search was conducted to identify relevant studies. Inclusion criteria encompassed studies that evaluated the use of ACEIs/ARBs in patients with CC and reported outcomes related to new cancer incidence and mortality. Data from selected studies were extracted and analyzed using appropriate statistical methods.

RESULTS

The study showed that fewer cancer cases occurred in patients who took ACEIs/ARBs compared to those who did not (RR 0.962, 95% CI 0.934-0.991, p = 0.010). Furthermore, patients with CC who utilized ACEIs/ARBs exhibited a decreased mortality rate compared to non-users (HR 0.833, 95% CI 0.640-1.085, p = 0.175).

CONCLUSION

This review suggests that using ACEIs/ARBs medicine could help people with CC live longer and lower their chances of dying. These results highlight the potential benefits of utilizing ACE inhibitors in the management of CC, warranting further investigation and consideration in clinical practice.

RAAS-deficient organoids indicate delayed angiogenesis as a possible cause for autosomal recessive renal tubular dysgenesis

Autosomal Recessive Renal Tubular Dysgenesis (AR-RTD) is a fatal genetic disorder characterized by complete absence or severe depletion of proximal tubules (PT) in patients harboring pathogenic variants in genes involved in the Renin-Angiotensin-Aldosterone System. To uncover the pathomechanism of AR-RTD, differentiation of ACE-/- and AGTR1-/- induced pluripotent stem cells (iPSCs) and AR-RTD patient-derived iPSCs into kidney organoids is leveraged. Comprehensive marker analyses show that both mutant and control organoids generate indistinguishable PT in vitro under normoxic (21% O2) or hypoxic (2% O2) conditions. Fully differentiated (d24) AGTR1-/- and control organoids transplanted under the kidney capsule of immunodeficient mice engraft and mature well, as do renal vesicle stage (d14) control organoids. By contrast, d14 AGTR1-/- organoids fail to engraft due to insufficient pro-angiogenic VEGF-A expression. Notably, growth under hypoxic conditions induces VEGF-A expression and rescues engraftment of AGTR1-/- organoids at d14, as does ectopic expression of VEGF-A. We propose that PT dysgenesis in AR-RTD is primarily a non-autonomous consequence of delayed angiogenesis, starving PT at a critical time in their development.

Immunoregulation mechanism of VEGF signaling pathway inhibitors and its efficacy on the kidney

Angiogenesis and immunosuppression are closely related pathophysiologic processes. Widely prescribed in malignant tumor and proliferative retinal lesions, VEGF signaling pathway inhibitors may cause hypertension and renal injury in some patients, presenting with proteinuria, nephrotic syndrome, renal failure and thrombotic microangiopathy. VEGF signaling pathway inhibitors block the action of both VEGF-A and VEGF-C. However, VEGF-A and VEGF-C produced by podocytes are vital to maintain the physiological function of glomerular endothelial cells and podocytes. There is still no effective treatment for kidney disease associated with VEGF signaling pathway inhibitors and some patients have progressive renal failure even after withdrawal of the drug. Recent studies reveal that blocking of VEGF-A and VEGF-C can activate CD4 +and CD8+ T cells, augment antigen-presenting function of dendritic cells, enhance cytotoxicity of macrophages and initiate complement cascade activation. VEGF and VEGFR are expressed in immune cells, which are involved in the immunosuppression and cross-talk among immune cells. This review summarizes the expression and function of VEGF-A and VEGF-C in the kidney. The current immunoregulation mechanisms of VEGF signaling pathway inhibitors are reviewed. Finally, combinate strategies are summarized to highlight the proposal for VEGF signaling pathway inhibitors.

Renin-angiotensin-aldosterone system inhibitors as a risk factor for chronic subdural hematoma recurrence: A matter of debate

OBJECTIVES

Chronic subdural hematoma (cSDH) is a common central nervous system condition. Recent reports indicate that cSDH affects long-term prognosis; however, its definitive risk factors remain unknown. An antihypertensive drug, renin-angiotensin-aldosterone system inhibitors (RAASi), can affect vascular permeability and cell proliferation processes, which may suppress the recurrence of cSDH. However, several studies have reported negative results to this effect. Therefore, we aimed to evaluate antihypertensive drugs, including RAASi, as risk factors for recurrent cSDH.

MATERIALS AND METHODS

A total of 203 consecutive cases of surgically treated cSDH were retrospectively reviewed. Clinical and radiological parameters were compared between the groups with and without cSDH recurrence to identify risk factors.

RESULTS

Of the included cases, 68 (33.5%) used RAASi and 37 (18.2%) developed recurrence within 60 days of surgery. In the multiple logistic regression analysis adjusted by composite risk score, the odds ratios (95% confidence interval) of RAASi, calcium channel blockers, diuretics, β and α blockers, for the recurrent risk of cSDH after surgery were 2.49 (1.16, 5.42), 1.79 (0.84, 3.82), 1.83 (0.62, 4.87), 0.90 (0.28, 2.44), and 0.96 (0.21, 3.20), respectively. The Cox proportional hazard model also demonstrated that RAASi-use was an independent risk factor for cSDH recurrence.

CONCLUSIONS

Present series suggests RAASi-use as a risk factor for cSDH recurrence, although the role of RAASi-use in cSDH remains debatable. Further studies for deeper understanding of the microenvironment of hematoma and the surroundings are preferable. (235 words).

Lymphatic vessels and the renin-angiotensin-system

The lymphatic system is an integral part of the circulatory system and plays an important role in the fluid homeostasis of the human body. Accumulating evidence has recently suggested the involvement of lymphatic dysfunction in the pathogenesis of cardio-reno-vascular (CRV) disease. However, how the sophisticated contractile machinery of lymphatic vessels is modulated and, possibly impaired in CRV disease, remains largely unknown. In particular, little attention has been paid to the effect of the renin-angiotensin-system (RAS) on lymphatics, despite the high concentration of RAS mediators that these tissue-draining vessels are exposed to and the established role of the RAS in the development of classic microvascular dysfunction and overt CRV disease. We herein review recent studies linking RAS to lymphatic function and/or plasticity and further highlight RAS-specific signaling pathways, previously shown to drive adverse arterial remodeling and CRV organ damage that have potential for direct modulation of the lymphatic system.

Different responses of the MIO‑M1 Mueller cell line to angiotensin II under hyperglycemic or hypoxic conditions

Members of the renin-angiotensin aldosterone system (RAAS) are expressed by various retinal tissues including Mueller glial cells. As the RAAS is hypothesized to play an important role in the pathogenesis of diseases that threaten vision, such as diabetic macular edema or retinal vein occlusion, the possible changes induced by exposure of the human cell line MIO-M1, an established model of Mueller cells, to angiotensin II or aldosterone for 6 h under hypoxic and/or hyperglycemic conditions were investigated. The mRNA expression levels of the members of the RAAS were assessed by reverse transcription-quantitative PCR, and the secretion of cytokines was assessed by ELISA. Under hyperglycemic conditions, the mRNA expression levels of the angiotensin-converting enzyme 2 (ACE2), angiotensin II receptors, AT1 and AT2, and the receptor of angiotensin (1-7) MAS1 were significantly higher after exposure to angiotensin II, and the expression of ACE2, AT2, and IL-6 (a marker of inflammation) was significantly increased after treatment with aldosterone; the expression of the other targets investigated remained unchanged. Significantly more IL-6 was secreted by MIO-M1 cells exposed to hyperglycemia and angiotensin. When cells were cultured in a hypoxic environment, additional treatment with aldosterone significantly increased the mRNA expression levels of ACE, but significantly more ACE2 mRNA was expressed in the presence of angiotensin II. Under hypoxic plus hyperglycemic conditions, significantly less ACE but more AT2 was expressed after treatment with angiotensin II, which also led to strongly elevated expression of IL-6. The mRNA expression levels of the angiogenic growth factor VEGF-A and secretion of the encoded protein were notably increased under hypoxic and hypoxic plus hyperglycemic conditions, irrespective of additional treatment with angiotensin II or aldosterone. These findings suggest that angiotensin II induces a pro-inflammatory response in MIO-M1 cells under hyperglycemic conditions despite activation of the counteracting ACE2/MAS1 signaling cascade. However, hypoxia results in an increased expression of angiogenic VEGF-A by these cells, which is not altered by angiotensin II or aldosterone.

The Multi-Kinase Inhibitor RepSox Enforces Barrier Function in the Face of Both VEGF and Cytokines

The therapeutic benefit provided by anti-vascular endothelial growth factor (VEGF) for patients with vision-threatening conditions such as diabetic retinopathy (DR) demonstrates the important role of VEGF in this affliction. Cytokines, which can be elevated in the vitreous of patients with DR, promote leakage of retinal blood vessels, and may also contribute to pathology, especially in those patients for whom anti-VEGF does not provide adequate benefit. In this in vitro study using primary human retinal endothelial cells, we compared anti-VEGF with the (transforming growth factor beta) TGFβ receptor inhibitor RepSox (RS) for their ability to enforce barrier function in the face of VEGF, cytokines, and the combination of both. RS was superior to anti-VEGF because it prevented permeability in response to VEGF, cytokines, and their combination, whereas anti-VEGF was effective against VEGF alone. The inhibitory effect of RS was associated with suppression of both agonist-induced pore formation and disorganization of adherens junctions. RS-mediated inhibition of the TGFβ pathway and increased expression of claudin-5 did not adequately explain how RS stabilized the endothelial cell barrier. Finally, RS not only prevented barrier relaxation, but also completely or partially reclosed a barrier relaxed with tumor necrosis factor α (TNF α) or VEGF, respectively. These studies demonstrate that RS stabilized the endothelial barrier in the face of both cytokines and VEGF, and thereby identify RS as a therapeutic that has the potential to overcome permeability driven by multiple agonists that play a role in the pathology of DR.

Activin A Limits VEGF-Induced Permeability via VE-PTP

The clinical success of neutralizing vascular endothelial growth factor (VEGF) has unequivocally identified VEGF as a driver of retinal edema that underlies a variety of blinding conditions. VEGF is not the only input that is received and integrated by the endothelium. For instance, the permeability of blood vessels is also regulated by the large and ubiquitously expressed transforming growth factor beta (TGF-β) family. In this project, we tested the hypothesis that members of the TGF-β family influence the VEGF-mediated control of the endothelial cell barrier. To this end, we compared the effect of bone morphogenetic protein-9 (BMP-9), TGF-β1, and activin A on the VEGF-driven permeability of primary human retinal endothelial cells. While BMP-9 and TGF-β1 had no effect on VEGF-induced permeability, activin A limited the extent to which VEGF relaxed the barrier. This activin A effect was associated with the reduced activation of VEGFR2 and its downstream effectors and an increased expression of vascular endothelial tyrosine phosphatase (VE-PTP). Attenuating the expression or activity of VE-PTP overcame the effect of activin A. Taken together, these observations indicate that the TGF-β superfamily governed VEGF-mediated responsiveness in a ligand-specific manner. Furthermore, activin A suppressed the responsiveness of cells to VEGF, and the underlying mechanism involved the VE-PTP-mediated dephosphorylation of VEGFR2.

Signaling pathways in vascular function and hypertension: molecular mechanisms and therapeutic interventions

Hypertension is a global public health issue and the leading cause of premature death in humans. Despite more than a century of research, hypertension remains difficult to cure due to its complex mechanisms involving multiple interactive factors and our limited understanding of it. Hypertension is a condition that is named after its clinical features. Vascular function is a factor that affects blood pressure directly, and it is a main strategy for clinically controlling BP to regulate constriction/relaxation function of blood vessels. Vascular elasticity, caliber, and reactivity are all characteristic indicators reflecting vascular function. Blood vessels are composed of three distinct layers, out of which the endothelial cells in intima and the smooth muscle cells in media are the main performers of vascular function. The alterations in signaling pathways in these cells are the key molecular mechanisms underlying vascular dysfunction and hypertension development. In this manuscript, we will comprehensively review the signaling pathways involved in vascular function regulation and hypertension progression, including calcium pathway, NO-NOsGC-cGMP pathway, various vascular remodeling pathways and some important upstream pathways such as renin-angiotensin-aldosterone system, oxidative stress-related signaling pathway, immunity/inflammation pathway, etc. Meanwhile, we will also summarize the treatment methods of hypertension that targets vascular function regulation and discuss the possibility of these signaling pathways being applied to clinical work.

VEGF Induces Expression of Genes That Either Promote or Limit Relaxation of the Retinal Endothelial Barrier

The purpose of this study was to identify genes that mediate VEGF-induced permeability. We performed RNA-Seq analysis on primary human retinal endothelial cells (HRECs) cultured in normal (5 mM) and high glucose (30 mM) conditions that were treated with vehicle, VEGF, or VEGF then anti-VEGF. We filtered our RNA-Seq dataset to identify genes with the following four characteristics: (1) regulated by VEGF, (2) VEGF regulation reversed by anti-VEGF, (3) regulated by VEGF in both normal and high glucose conditions, and (4) known contribution to vascular homeostasis. Of the resultant 18 genes, members of the Notch signaling pathway and ANGPT2 (Ang2) were selected for further study. Permeability assays revealed that while the Notch pathway was dispensable for relaxing the barrier, it contributed to maintaining an open barrier. In contrast, Ang2 limited the extent of barrier relaxation in response to VEGF. These findings indicate that VEGF engages distinct sets of genes to induce and sustain barrier relaxation. Furthermore, VEGF induces expression of genes that limit the extent of barrier relaxation. Together, these observations begin to elucidate the elegance of VEGF-mediated transcriptional regulation of permeability.

The role of aldosterone in the pathogenesis of diabetic retinopathy

Aldosterone, as a mineralocorticoid of adrenal origin, has effects that are not limited to the urinary tract. As an important regulator in Vasoactive hormone pathways, aldosterone may play an effect in the pathogenesis of diabetic retinopathy (DR) through the regulation of oxidative stress, vascular regulation, and inflammatory mechanisms. This implies that mineralocorticoids, including aldosterone, have great potential and value for the diagnosis and treatment of DR. Because early studies did not focus on the intrinsic association between mineralocorticoids and DR, targeted research is still in its infancy and there are still many obstacles to its application in the clinical setting. Recent studies have improved the understanding of the effects of aldosterone on DR, and we review them with the aim of exploring possible mechanisms for the treatment and prevention of DR.

Aldosterone as a Possible Contributor to Eye Diseases

Aldosterone, an effector molecule of the renin-angiotensin-aldosterone system (RAAS), has been receiving more attention in the field of ophthalmology because of its possible role in the pathogenesis of various eye diseases or abnormalities; it may even become a target for their treatment. Primary aldosteronism, a typical model of a systemic aldosterone excess, may cause vision loss due to various ocular diseases, such as retinal vein occlusion, central serous chorioretinopathy, and, possibly glaucoma. RAAS components are present in various parts and types of cells present in the eye. Investigations of the local RAAS in various animal models of diabetic macular edema, retinal vein occlusion, retinopathy of prematurity, central serous chorioretinopathy, and glaucoma have found evidence that aldosterone or mineralocorticoid receptors may exacerbate the pathology of these disorders. Further studies are needed to elucidate whether the modulation of aldosterone or mineralocorticoid receptors is an effective treatment for preventing vision loss in patients with eye diseases.

Hyperglycemia Promotes Mitophagy and Thereby Mitigates Hyperglycemia-Induced Damage

The observation that diabetic retinopathy (DR) typically takes decades to develop suggests the existence of an endogenous system that protects from diabetes-induced damage. To investigate the existance of such a system, primary human retinal endothelial cells were cultured in either normal glucose (5 mmol/L) or high glucose (30 mmol/L; HG). Prolonged exposure to HG was beneficial instead of detrimental. Although tumor necrosis factor-α-induced expression of vascular cell adhesion molecule 1 and intercellular adhesion molecule 1 was unaffected after 1 day of HG, it waned as the exposure to HG was extended. Similarly, oxidative stress-induced death decreased with prolonged exposure to HG. Furthermore, mitochondrial functionality, which was compromised by 1 day of HG, was improved by 10 days of HG, and this change required increased clearance of damaged mitochondria (mitophagy). Finally, antagonizing mitochondrial dynamics compromised the cells' ability to endure HG: susceptibility to cell death increased, and basal barrier function and responsiveness to vascular endothelial growth factor deteriorated. These observations indicate the existence of an endogenous system that protects human retinal endothelial cells from the deleterious effects of HG. Hyperglycemia-induced mitochondrial adaptation is a plausible contributor to the mechanism responsible for the delayed onset of DR; loss of hyperglycemia-induced mitochondrial adaptation may set the stage for the development of DR.

Risk factor analysis and clinical decision tree model construction for diabetic retinopathy in Western China

BACKGROUND

Diabetic retinopathy (DR) is the driving force of blindness in patients with type 2 diabetes mellitus (T2DM). DR has a high prevalence and lacks effective therapeutic strategies, underscoring the need for early prevention and treatment. Yunnan province, located in the southwest plateau of China, has a high pre-valence of DR and an underdeveloped economy.

AIM

To build a clinical prediction model that will enable early prevention and treatment of DR.

METHODS

In this cross-sectional study, 1654 Han population with T2DM were divided into groups without (n = 826) and with DR (n = 828) based on fundus photography. The DR group was further subdivided into non-proliferative DR (n = 403) and proliferative DR (n = 425) groups. A univariate analysis and logistic regression analysis were conducted and a clinical decision tree model was constructed.

RESULTS

Diabetes duration ≥ 10 years, female sex, standing- or supine systolic blood pressure (SBP) ≥ 140 mmHg, and cholesterol ≥ 6.22 mmol/L were risk factors for DR in logistic regression analysis (odds ratio = 2.118, 1.520, 1.417, 1.881, and 1.591, respectively). A greater severity of chronic kidney disease (CKD) or hemoglobin A 1c increased the risk of DR in patients with T2DM. In the decision tree model, diabetes duration was the primary risk factor affecting the occurrence of DR in patients with T2DM, followed by CKD stage, supine SBP, standing SBP, and body mass index (BMI). DR classification outcomes were obtained by evaluating standing SBP or BMI according to the CKD stage for diabetes duration < 10 years and by evaluating CKD stage according to the supine SBP for diabetes duration ≥ 10 years.

CONCLUSION

Based on the simple and intuitive decision tree model constructed in this study, DR classification outcomes were easily obtained by evaluating diabetes duration, CKD stage, supine or standing SBP, and BMI.

Cardiovascular aspects of the (pro)renin receptor: Function and significance

Cardiovascular diseases (CVDs), including all types of disorders related to the heart or blood vessels, are the major public health problems and the leading causes of mortality globally. (Pro)renin receptor (PRR), a single transmembrane protein, is present in cardiomyocytes, vascular smooth muscle cells, and endothelial cells. PRR plays an essential role in cardiovascular homeostasis by regulating the renin-angiotensin system and several intracellular signals such as mitogen-activated protein kinase signaling and wnt/β-catenin signaling in various cardiovascular cells. This review discusses the current evidence for the pathophysiological roles of the cardiac and vascular PRR. Activation of PRR in cardiomyocytes may contribute to myocardial ischemia/reperfusion injury, cardiac hypertrophy, diabetic or alcoholic cardiomyopathy, salt-induced heart damage, and heart failure. Activation of PRR promotes vascular smooth muscle cell proliferation, endothelial cell dysfunction, neovascularization, and the progress of vascular diseases. In addition, phenotypes of animals transgenic for PRR and the hypertensive actions of PRR in the brain and kidney and the soluble PRR are also discussed. Targeting PRR in local tissues may offer benefits for patients with CVDs, including heart injury, atherosclerosis, and hypertension.

Modified Qing' e Pills exerts anti-osteoporosis effects and prevents bone loss by enhancing type H blood vessel formation

OBJECTIVE

To explore whether the modified Qing' e Pills (MQEP) exerts anti-osteoporotic effects and prevents bone loss by enhancing angiogenesis.

METHODS

Network pharmacology was used to assess whether MQEP has a pro-angiogenic capacity and to predict its potential targets. Human umbilical vein endothelial cells were treated with glucocorticoids and MQEP to assess cell viability. The expression of angiotensin II type 1 receptor, angiotensin II type 2 receptor, and angiotensin converting enzyme, which are associated with the activation of the renin-angiotensin-aldosterone system, and the expression of vascular endothelial growth factor and hypoxia-inducible factor 1 alpha, which are associated with the formation of type H blood vessels, were examined by western blot and RT-qPCR. Thereafter, the glucocorticoid-induced osteoporosis model was established and intervened with MQEP. Femur scanning was performed with micro-computed tomography; trabecular spacing, trabecular thickness, and trabecular number were observed and calculated; the expression of nuclear factor-kappa B ligand and osteoprotegerin was detected by ELISA, and the ratio was calculated to evaluate the degree of bone resorption. Finally, type H blood vessels that were highly coupled to osteogenic cells were identified by immunohistochemistry staining and flow cytometry.

RESULTS

This is the first study to reveal and confirm that MQEP could prevent bone loss in glucocorticoid-induced osteoporosis by promoting the expression of hypoxia-inducible factor 1 alpha and vascular endothelial growth factor, which are highly associated with type H blood vessel formation. In vitro experiments confirmed that MQEP could effectively promote the proliferation of vascular endothelial cells and alleviate glucocorticoids-induced activation of the renin-angiotensin-aldosterone system, thereby reducing vascular injury.

CONCLUSION

MQEP exerts anti-osteoporosis effects and prevents bone loss by alleviating vascular injury caused by renin-angiotensin-aldosterone system activation and promoting type H blood vessel formation.

The Role of the Wnt Pathway in VEGF/Anti-VEGF-Dependent Control of the Endothelial Cell Barrier

Purpose

Investigate the contribution of the Wnt pathway to vascular endothelial growth factor (VEGF)/anti-VEGF-mediated control of endothelial cell permeability.

Methods

High glucose-treated primary human retinal endothelial cells (HRECs) were exposed to either VEGF, or VEGF and then anti-VEGF. Changes in gene expression were assayed by RNAseq and qRT-PCR. Permeability was monitored by electrical cell-substrate impedance sensing (ECIS). Approaches to activate the Wnt pathway included treatment with LiCl and overexpression of constitutively activated β-catenin. β-catenin-dependent transcriptional activity was monitored in HRECs stably expressing a TCF/LEF-driven reporter.

Results

VEGF/anti-VEGF altered expression of genes encoding many members of the Wnt pathway. A subset of these genes was regulated in a way that is likely to contribute to control of the endothelial cell barrier. Namely, the VEGF-induced alteration of expression of such genes was reversed by anti-VEGF, and such adjustments occurred at times corresponding to changes in barrier function. While pharmacological and molecular approaches to activate the Wnt pathway had no effect on basal permeability, they suppressed VEGF-induced relaxation. Furthermore, anti-VEGF-mediated restoration of barrier function was unaffected by activation of the Wnt pathway.

Conclusions

VEGF/anti-VEGF engages multiple members of the Wnt pathway, and activating this pathway enforces the endothelial barrier by attenuating VEGF-induced relaxation. These data suggest that FDA-approved agents such as LiCl may be an adjuvant to anti-VEGF therapy for patients afflicted with blinding conditions including diabetic retinopathy.

[Bradykinin and angiotensin-converting enzyme in serum of patients with diabetic retinopathy and the prognosis of diabetic macular edema development (pilot study)]

BACKGROUND

Diabetic macular edema (DME) is a microvascular complication of diabetic retinopathy. One of the key roles in the pathogenesis of DME may belong to the components of rennin-angiotensin and kallikrein-kinin systems: bradykinin (Bk) and angiotensin-converting enzyme (ACE).

PURPOSE

To determine the Bk and ACE concentration and ACE activity in serum of patients with proliferative diabetic retinopathy (PDR) and to estimate the significance of these parameters for the early diagnostic and prognosis of DMO.

MATERIALS AND METHODS

Serum was collected from the 2 groups of patients with II type diabetes. Group I (n=9) had DME, group II (n=27) had PDR without DME. Control group (n=14) consisted of adult volonteers without diabetes and ophthalmic diseases. Concentration of Bk and ACE was measured using ELISA kits, ACE activity was determined enzymatically with specific fluorogenic substrate.

RESULTS

Concentration of Bk in serum of patients without DME did not differ from one in controls (12,00 (9,70; 12,40) pg/ml) while all patients with DME had Bk level of 14,69 (13,68; 16,78) pg/ml that was significantly higher (p<0,01). In patients without DME ACE concentration (88,60 (77,30; 97,45) ng/ml) and ACE activity (6,8 (5,1;7,1) nmol/min·ml) were higher than normal (p<0,01) while in the case of DME concentration of ACE increased (77,36 (70,24; 86,29 ng/ml, p<0,01) and activity remained normal. The Bk/ACE concentrations ratio decreased in patients without DME and increased in those having DME.

CONCLUSION

Patients with DME have increased Bk concentration along with nearly normal ACE concentration that indicate predominance of Bk synthesis over its degradation that may lead to the DME development. The Bk/ACE ratio decrease in patients with uncomplicated PDR and increase significantly in ones with DME. It means that determination of Bk in serum of patients with PDR may be used for the prediction of DME development. The Bk/ACE concentrations ratio may be even more informative.

Genetics of Diabetic Retinopathy, a Leading Cause of Irreversible Blindness in the Industrialized World

Diabetic retinopathy (DR) is a chronic complication of diabetes and a leading cause of blindness in the industrialized world. Traditional risk factors, such as glycemic control and duration of diabetes, are unable to explain why some individuals remain protected while others progress to a more severe form of the disease. Differences are also observed in DR heritability as well as the response to anti-vascular endothelial growth factor (VEGF) treatment. This review discusses various aspects of genetics in DR to shed light on DR pathogenesis and treatment. First, we discuss the global burden of DR followed by a discussion on disease pathogenesis as well as the role genetics plays in the prevalence and progression of DR. Subsequently, we provide a review of studies related to DR’s genetic contribution, such as candidate gene studies, linkage studies, and genome-wide association studies (GWAS) as well as other clinical and meta-analysis studies that have identified putative candidate genes. With the advent of newer cutting-edge technologies, identifying the genetic components in DR has played an important role in understanding DR incidence, progression, and response to treatment, thereby developing newer therapeutic targets and therapies.

MiR-195 inhibits the ubiquitination and degradation of YY1 by Smurf2, and induces EMT and cell permeability of retinal pigment epithelial cells

The dysregulated microRNAs (miRNAs) are involved in diabetic retinopathy progression. Epithelial mesenchymal transition (EMT) and cell permeability are important events in diabetic retinopathy. However, the function and mechanism of miR-195 in EMT and cell permeability in diabetic retinopathy remain largely unclear. Diabetic retinopathy models were established using streptozotocin (STZ)-induced diabetic mice and high glucose (HG)-stimulated ARPE-19 cells. Retina injury was investigated by hematoxylin-eosin (HE) staining. EMT and cell permeability were analyzed by western blotting, immunofluorescence, wound healing, and FITC-dextran assays. MiR-195 expression was detected via qRT-PCR. YY1, VEGFA, Snail1, and Smurf2 levels were detected via western blotting. The interaction relationship was analyzed via ChIP, Co-IP, or dual-luciferase reporter assay. The retina injury, EMT, and cell permeability were induced in STZ-induced diabetic mice. HG induced EMT and cell permeability in ARPE-19 cells. MiR-195, YY1, VEGFA, and Snail1 levels were enhanced, but Smurf2 abundance was reduced in STZ-induced diabetic mice and HG-stimulated ARPE-19 cells. VEGFA knockdown decreased Snail1 expression and attenuated HG-induced EMT and cell permeability. YY1 silence reduced VEGFA and Snail1 expression, and mitigated HG-induced EMT and cell permeability. YY1 could bind with VEGFA and Snail1, and it was degraded via Smurf2-mediated ubiquitination. MiR-195 knockdown upregulated Smurf2 to decrease YY1 expression and inhibited HG-induced EMT and cell permeability. MiR-195 targeted Smurf2, increased expression of YY1, VEGFA, and Snail1, and promoted HG-induced EMT and cell permeability. MiR-195 promotes EMT and cell permeability of HG-stimulated ARPE-19 cells by increasing VEGFA/Snail1 via inhibiting the Smurf2-mediated ubiquitination of YY1.

Perindopril Reduces Arterial Pressure and Does Not Inhibit Exercise-Induced Angiogenesis in Spontaneously Hypertensive Rats

ABSTRACT

Sympathetic activity, arteriolar structure, and angiogenesis are important mechanisms modulating hypertension and this study aimed to analyze the effects of perindopril treatment, associated or not with exercise training, on the mechanisms that control blood pressure (BP) in hypertensive rats. Spontaneously hypertensive rats (SHR) were allocated into 4 groups: 1/sedentary (S); 2/perindopril (P, 3.0 mg/kg/d); 3/trained (T); and 4/trained + perindopril (TP). Wistar rats were used as normotensive sedentary control group. SHR were assigned to undergo a treadmill training (T) or were kept sedentary. Heart rate, BP, sympathetic activity to the vessels (LF-SBP), and skeletal muscle and myocardial morphometric analyses were performed. BP was significantly lower after all 3 strategies, compared with S and was accompanied by lower LF-SBP (-76%, -53%, and -44%, for P, T, and TP, respectively). Arteriolar vessel wall cross-sectional area was lower after treatments (-56%, -52%, and -56%, for P, T, and TP, respectively), and only TP presented higher arteriolar lumen area. Capillary rarefaction was present in soleus muscle and myocardium in S group and both trained groups presented higher vessel density, although perindopril attenuated this increase in soleus muscle. Although myocyte diameter was not different between groups, myocardial collagen deposition area, higher in S group, was lower after 3 strategies. In conclusion, we may suggest that perindopril could be an option for the hypertensive people who practice exercise and need a specific pharmacological treatment to reach a better BP control, mainly because training-induced angiogenesis is an important response to facilitate blood flow perfusion and oxygen uptake and perindopril did not attenuate this response.

Metabolic Dysregulation in Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fibroproliferative disorder limited to the lung. New findings, starting from our proteomics studies on IPF, suggest that systemic involvement with altered molecular mechanisms and metabolic disorder is an underlying cause of fibrosis. The role of metabolic dysregulation in the pathogenesis of IPF has not been extensively studied, despite a recent surge of interest. In particular, our studies on bronchoalveolar lavage fluid have shown that the renin–angiotensin–aldosterone system (RAAS), the hypoxia/oxidative stress response, and changes in iron and lipid metabolism are involved in onset of IPF. These processes appear to interact in an intricate manner and to be related to different fibrosing pathologies not directly linked to the lung environment. The disordered metabolism of carbohydrates, lipids, proteins and hormones has been documented in lung, liver, and kidney fibrosis. Correcting these metabolic alterations may offer a new strategy for treating fibrosis. This paper focuses on the role of metabolic dysregulation in the pathogenesis of IPF and is a continuation of our previous studies, investigating metabolic dysregulation as a new target for fibrosis therapy.