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Elevated plasma homocysteine (Hcy) is associated with cerebrovascular disease and activates matrix metalloproteinases (MMPs), which lead to vascular remodeling that could disrupt the blood-brain barrier. To determine whether Hcy administration can increase brain microvascular leakage secondary to activation of MMPs, we examined pial venules by intravital video micros-copy through a craniotomy in anesthetized mice. Bovine serum albumin labeled with fluorescein isothiocyanate (BSA-FITC) was injected into a carotid artery to measure extravenular leakage. Hcy (30 μM/total blood volume) was injected 10 min after FITC-BSA injection. Four groups of mice were examined: 1) wild type (WT) given vehicle; 2) WT given Hcy (WT + Hcy); 3) MMP-9 gene knockout given Hcy (MMP-9-/- + Hcy); and 4) MMP-9-/- with topical application of histamine (10-4 M) (MMP- 9-/- + histamine). In the WT + Hcy mice, leakage of F1TC-BSA from pial venules was significantly (P < 0.05) greater than in the other groups. There was no significant leakage of pial microvessels in MMP-9-/- + Hcy mice. Increased cerebrovascular leakage in the MMP-9-/- + histamine group showed that microvascular permeability could still increase by a mechanism independent of MMP-9. Treatment of cultured mouse microvascular endothelial cells with 30 μM Hcy resulted in significantly greater F-actin formation than in control cells without Hcy. Treatment with a broad-range MMP inhibitor (GM-6001; 1 μM) ameliorated Hcy-induced F-actin formation. These data suggest that Hcy increases microvascular permeability, in part, through MMP-9 activation. [ABSTRACT FROM AUTHOR]

Age-related macular degeneration (AMD) is a leading cause of blindness and is becoming a global crisis since affected people will increase to 288 million by 2040. Genetics, age, diabetes, gender, obesity, hypertension, race, hyperopia, iris-color, smoking, sun-light and pyroptosis have varying roles in AMD, but oxidative stress-induced inflammation remains a significant driver of pathobiology. Eye is a unique organ as it contains a remarkable oxygen-gradient that generates reactive oxygen species (ROS) which upregulates inflammatory pathways. ROS becomes a source of functional and morphological impairments in retinal pigment epithelium (RPE), endothelial cells and retinal ganglion cells. Reports demonstrated that hydrogen sulfide (H2S) acts as a signaling molecule and that it may treat ailments. Therefore, we propose a novel hypothesis that H2S may restore homeostasis in the eyes thereby reducing damage caused by oxidative injury and inflammation. Since H2S has been shown to be a powerful antioxidant because of its free-radicals’ inhibition properties in addition to its beneficial effects in age-related conditions, therefore, patients may benefit from H2S salubrious effects not only by minimizing their oxidant and inflammatory injuries to retina but also by lowering retinal glutamate excitotoxicity.

Past 25y have witnessed an exponential increase in knowledge and understanding of ocular diseases and their respective genetic underpinnings. As a result, scientists have mapped many genes and their variants that can influence vision and health of our eyes. Based on these findings, it is becoming clear that an early diagnosis employing genetic testing can help evaluate patients’ conditions for instituting treatment plan(s) and follow-up care to avoid vision complications later. For example, knowing family history becomes crucial for inherited eye diseases as it can benefit members in family who may have similar eye diseases or predispositions. Therefore, gathering information from an elaborate examination along with complete assessment of past medical illness by ophthalmologists followed by consultation with geneticists can help create a roadmap for making diagnosis and treatment precise and beneficial. In this review, we present an update on ocular genomic medicine that we believe has tremendous potential towards unraveling genetic implications in ocular diseases and patients’ susceptibilities. We also discuss translational aspects of genetic ophthalmology and genome engineering that may help advance molecular diagnostics and therapeutics.

There are many vision threatening diseases of the eye affecting millions of people worldwide. In this article, we are summarizing potential role of various matrix metalloproteinases (MMPs); the Zn (2+)-dependent endoproteases in eye health along with pathogenesis of prominent ocular diseases such as macular degeneration, diabetic retinopathy, and glaucoma via understanding MMPs regulation in affected patients, interactions of MMPs with their substrate molecules, and key regulatory functions of tissue inhibitor of metalloproteinases (TIMPs) towards maintaining overall homeostasis.

AIM: To test whether homocysteine (Hcy) can influence the transcriptional profile, we hypothesized that Hcy can lead to the induction of proinflammatory molecules in the retinal cells of aging people. METHODS: An unbiased in vitro inflammatory pathway focused study was designed employing retinal pigment epithelial (RPE) cell line, ARPE-19. Cells were cultured in the presence or absence of Hcy to capture target genes’ expression profile. Three different concentrations of Hcy were added in the culture medium of confluent monolayers. cRNAs were made from the isolated total RNAs and the labeled cRNA probes were hybridized to microarrays specific for human disease pathway inflammatory cytokines, chemokines and their receptor gene micro-array panels as per manufacture’s recommendations. Two Hcy up-regulated molecules: IL6 and CEBPB were further validated via Western blot analysis. Hcy’s effect on ARPE-19 cellular morphology and genomic DNA integrity were also evaluated. RESULTS: Gene microarray analyses of RPE cells in response to Hcy treatment revealed alterations in the expressions of several inflammatory gene transcripts such as CCL5, CEBPB, IL13RA2, IL15RA, IL6, IL8 and CXCL3 that were up-regulated. The transcripts for C3, CCL2, IL11RA and IL18 genes exhibited down-regulation. The IL6 and CEBPB expressions were subsequently validated at the protein levels. Treatment of the retinal cells with increasing Hcy concentration influenced their density in culture however their morphology and DNA integrity remained unaffected. CONCLUSION: These findings suggest that Hcy can potentially mediate the expression of chemokines, cytokines and interleukins receptors in the retinal cells without having any debilitating effects on their morphology and the genomic DNA integrity.

Diabetic patients suffer from a host of physiological abnormalities beyond just those of glucose metabolism. These abnormalities often lead to systemic inflammation via modulation of several inflammation-related genes, their respective gene products, homocysteine metabolism, and pyroptosis. The very nature of this homeostatic disruption re-sets the overall physiology of diabetics via upregulation of immune responses, enhanced retinal neovascularization, upregulation of epigenetic events, and disturbances in cells’ redox regulatory system. This altered pathophysiological milieu can lead to the development of diabetic retinopathy (DR), a debilitating vision-threatening eye condition with microvascular complications. DR is the most prevalent cause of irreversible blindness in the working-age adults throughout the world as it can lead to severe structural and functional remodeling of the retina, decreasing vision and thus diminishing the quality of life. In this manuscript, we attempt to summarize recent developments and new insights to explore the very nature of this intertwined crosstalk between components of the immune system and their metabolic orchestrations to elucidate the pathophysiology of DR. Understanding the multifaceted nature of the cellular and molecular factors that are involved in DR could reveal new targets for effective diagnostics, therapeutics, prognostics, preventive tools, and finally strategies to combat the development and progression of DR in susceptible subjects.

Exogenous hydrogen sulfide (H2S) leads to down-regulation of inflammatory responses and provides myocardial protection during acute ischemia/reperfusion injury; however its role during chronic heart failure (CHF) due to myocardial infarction (MI) is yet to be unveiled. We previously reported that H2S inhibits antiangiogenic factors such, as endostatin and angiostatin, but a little is known about its effect on parstatin (a fragment of proteinase-activated receptor-1, PAR-1). We hypothesize that H2S inhibits parstatin formation and promotes VEGF activation, thus promoting angiogenesis and significantly limiting the extent of MI injury. To verify this hypothesis MI was created in 12 week-old male mice by ligation of left anterior descending artery (LAD). Sham surgery was performed except LAD ligation. After the surgery mice were treated with sodium hydrogen sulfide (30 μmol/l NaHS, a donor for H2S, in drinking water) for 4 weeks. The LV tissue was analyzed for VEGF, flk-1 and flt-1, endostatin, angiostatin and parstatin. The expression of VEGF, flk-1 and flt-1 were significantly increased in treated mice while the level of endostatin, angiostatin and parstatin were decreased compared to in untreated mice. The echocardiography in mice treated with H2S showed the improvement of heart function compared to in untreated mice. The X-ray and Doppler blood flow measurements showed enhancement of cardiac-angiogenesis in mice treated with H2S. This observed cytoprotection was associated with an inhibition of anti-angiogenic proteins and stimulation of angiogenic factors. We established that administration of H2S at the time of MI ameliorated infarct size and preserved LV function during development of MI in mice. These results suggest that H2S is cytoprotective and angioprotective during evolution of MI.

Background: Homocysteine (Hcy) is an independent cardiovascular risk factor; however, in diabetes, the role of tissue Hcy leading to cardiac dysfunction is unclear. Aims: To determine whether tissue Hcy caused endothelial-myocyte uncoupling and ventricular dysfunction in diabetes. Methods: Diabetes was created in C57BL/6J male mice by injecting 65 mg/kg alloxan. To reverse diabetic complications, ciglitazone (CZ) was administered in the drinking water. Plasma glucose, Hcy, left ventricular (LV) tissue levels of Hcy and nitric oxide (NO) were measured. Glomerular filtration rate (GFR) was measured by inulin-FITC. Endothelial-myocyte coupling was measured in cardiac rings. In vivo diastolic relaxation and LV diameters were measured by a Millar catheter in LV and by M-mode echocardiography, respectively. Results: Plasma glucose, GFR and LV tissue Hcy were increased in diabetic mice and were normalized after CZ treatment; whereas, elevated plasma Hcy level remained unchanged with or without CZ treatment. NO levels in the LV were found inversely related to tissue Hcy levels. Attenuated endothelial-myocyte function in diabetic mice was ameliorated by CZ treatment. Cardiac relaxation, the ratio of LV wall thickness to LV diameter was decreased in diabetes, and normalized after CZ treatment. Conclusion: CZ normalized LV tissue levels of Hcy and ameliorated endothelial-myocyte coupling; therefore, specifically suggest the association of LV tissue Hcy levels with impair endothelial-myocyte function in diabetes.

Elevated oxidative stress has been characterized in numerous disorders including systemic hypertension, arterial stiffness, left ventricular hypertrophy (LVH) and heart failure. The peroxisome proliferator activated receptor gamma (PPARγ) ameliorates oxidative stress and LVH. To test the hypothesis that PPARγ decreased LVH and cardiac fibrosis in chronic pressure overload, in part, by increasing SOD, eNOS and elastin and decreasing NOX4, MMP and collagen synthesis and degradation, chronic pressure overload analogous to systemic hypertension was created in C57BL/6J mice by occluding the abdominal aorta above the kidneys (aortic stenosis-AS). The sham surgery was used as controls. Ciglitazone (CZ, a PPARγ agonist, 4 µg/ml) was administered in drinking water. LV function was measured by M-Mode Echocardiography. We found that PPARγ protein levels were increased by CZ. NOX-4 expression was increased by pressure-overload and such an increase was attenuated by CZ. SOD expression was not affected by CZ. Expression of iNOS was induced by pressure-overload, and such an increase was inhibited by CZ. Protein levels for MMP2, MMP-9, MMP-13 were induced and TIMP levels were decreased by pressure-overload. The CZ mitigated these levels. Collagen synthesis was increased and elastin levels were decreased by pressure-overload and CZ ameliorated these changes. Histochemistry showed that CZ inhibited interstitial and perivascular fibrosis. Echocardiography showed that CZ attenuated the systolic and diastolic LV dysfunction induced by pressure-overload. These observations suggested that CZ inhibited pressure-overlaod-induced cardiac remodeling, and inhibition of an induction of NOX4, iNOS, MMP-2/MMP-13 expression and collagen synthesis/degradation may play a role in pressure-overload induced cardiac remodeling.

We have previously reported the role of anti-angiogenic factors in inducing the transition from compensatory cardiac hypertrophy to heart failure and the significance of MMP-9 and TIMP-3 in promoting this process during pressure overload hemodynamic stress. Several studies reported the evidence of cardiac autophagy, involving removal of cellular organelles like mitochondria (mitophagy), peroxisomes etc., in the pathogenesis of heart failure. However, little is known regarding the therapeutic role of mitochondrial division inhibitor (Mdivi) in the pressure overload induced heart failure. We hypothesize that treatment with mitochondrial division inhibitor (Mdivi) inhibits abnormal mitophagy in a pressure overload heart and thus ameliorates heart failure condition.To verify this, ascending aortic banding was done in wild type mice to create pressure overload induced heart failure and then treated with Mdivi and compared with vehicle treated controls.Expression of MMP-2, vascular endothelial growth factor, CD31, was increased, while expression of anti angiogenic factors like endostatin and angiostatin along with MMP-9, TIMP-3 was reduced in Mdivi treated AB 8 weeks mice compared to vehicle treated controls. Expression of mitophagy markers like LC3 and p62 was decreased in Mdivi treated mice compared to controls. Cardiac functional status assessed by echocardiography showed improvement and there is also a decrease in the deposition of fibrosis in Mdivi treated mice compared to controls.Above results suggest that Mdivi inhibits the abnormal cardiac mitophagy response during sustained pressure overload stress and propose the novel therapeutic role of Mdivi in ameliorating heart failure.