High glucose and homocysteine synergistically affect the metalloproteinases-tissue inhibitors of metalloproteinases pattern, but not TGFB expression, in human fibroblasts

Mild hyperhomocysteinemia induces blood-brain barrier dysfunction but not neuroinflammation in the cerebral cortex and hippocampus of wild-type mice

This study explored the potential effects of mild hyperhomocysteinemia (HHcy) on the blood-brain barrier (BBB) and neuroinflammation. Seven-week-old male wild-type C57BL/6 mice were fed normal mouse chow (the control group) or a methionine-enriched diet (the HHcy group) for 14 weeks. Mice in the HHcy group exhibited a slight increase in serum Hcy levels (13.56 ± 0.61 μmol/L). Activation of the ERK signaling pathway, up-regulation of matrix metalloproteinase-9 (MMP-9), and degradation of tight junction proteins (occludin and claudin-5) were observed in both the cerebral cortex and hippocampus of mice with mild HHcy. However, microglia were not activated and the levels of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were not changed in either the cerebral cortex or hippocampus of mice with mild HHcy. Moreover, the signaling activity of STAT3 also did not differ significantly between the two groups. These findings demonstrate that the BBB is highly vulnerable to homocysteine insult. Even a slight increase in serum homocysteine levels up-regulates MMP-9 expression and disrupts the BBB integrity. Meanwhile, microglia activation or the STAT3 pathway might not contribute to the effects of mild HHcy on the brain.

Homocysteine Disrupts Balance between MMP-9 and Its Tissue Inhibitor in Diabetic Retinopathy: The Role of DNA Methylation

High homocysteine is routinely observed in diabetic patients, and this non-protein amino acid is considered as an independent risk factor for diabetic retinopathy. Homocysteine biosynthesis from methionine forms S-adenosyl methionine (SAM), which is a major methyl donor critical in DNA methylation. Hyperhomocysteinemia is implicated in increased oxidative stress and activation of MMP-9, and in diabetic retinopathy, the activation of MMP-9 facilitates capillary cell apoptosis. Our aim was to investigate the mechanism by which homocysteine activates MMP-9 in diabetic retinopathy. Human retinal endothelial cells, incubated with/without 100 μM homocysteine, were analyzed for MMP-9 and its tissue inhibitor Timp1 expressions and interactions, and ROS levels. Timp1 and MMP-9 promoters were analyzed for methylated and hydroxymethylated cytosine levels (5mC and 5hmC respectively) by the DNA capture method, and DNA- methylating (Dnmt1) and hydroxymethylating enzymes (Tet2) binding by chromatin immunoprecipitation. The results were confirmed in retinal microvessels from diabetic rats receiving homocysteine. Homocysteine supplementation exacerbated hyperglycaemia-induced MMP-9 and ROS levels and decreased Timp1 and its interactions with MMP-9. Homocysteine also aggravated Dnmts and Tets activation, increased 5mC at Timp1 promoter and 5hmC at MMP-9 promoter, and suppressed Timp1 transcription and activated MMP-9 transcription. Similar results were obtained from retinal microvessels from diabetic rats receiving homocysteine. Thus, hyperhomocysteinemia in diabetes activates MMP-9 functionally by reducing Timp1-MMP-9 interactions and transcriptionally by altering DNA methylation-hydroxymethylation of its promoter. The regulation of homocysteine could prevent/slow down the development of retinopathy and prevent their vision loss in diabetic patients.

MDI 301, a synthetic retinoid, depressed levels of matrix metalloproteinases and oxidative stress in diabetic dermal fibroblasts

Diabetic foot ulcerations could result in serious consequences such as amputations. The up-regulation of matrix metalloproteinases and down-regulation of TIMP1 were remarked as distinctive biological characteristics in the diabetic dermal fibroblast. The current study was performed in order to clarify the effect of high glucose on formation of diabetic dermal fibroblast cell. In addition, the effect of MDI 301 on ameliorating diabetic fibroblasts was investigated in this study. The mRNA and protein expression levels of MMPs, TIMP1 and catalase were evaluated against fibroblasts treated with high glucose (30 mM) using qRT-PCR, western blotting and zymography assays. Methods were also employed for investigating the biological effects of MDI 301 on high glucose-induced diabetic fibroblasts. In this study, we found that the unbalance of oxidative stress induced by high glucose concentration play an important role in the formation of diabetic dermal fibroblast from normal cells. In addition, MDI 301, a picolinic acid-substituted ester of 9-cis retinoic acid was employed in this study in order to ameliorate symptoms on diabetic dermal fibroblast induced by high glucose concentration. We found MDI 301 alleviate the effects of high glucose-induced skin damage by balancing the oxidative stress and regulating the MMPs and TIMP1 levels. Our finding indicated that MDI 301 offers the potential for repairing the faulty skin function arising from diabetes.

Myricetin, a potent natural agent for treatment of diabetic skin damage by modulating TIMP/MMPs balance and oxidative stress

Foot ulceration is a major cause of morbidity in patients with diabetes, and abnormal peripheral neuropathy often results in hospitalization. Up-regulation of matrix metalloproteinases and down-regulation of tissue inhibitor of metalloproteinase 1 are noted to be distinctive biological functions of diabetic dermal fibroblasts. The aim of this study was to evaluate the biological effects of modified retinoids on diabetic fibroblasts. Myricetin, a natural compound, balances the TIMP1/MMP ratio and oxidative stress in diabetic fibroblasts. Our results indicate that myricetin significantly ameliorates the effects of diabetes on dermal fibroblasts. In addition, we found that the oxidative stress imbalance induced by a high glucose concentration plays an important role in the changes to dermal fibroblasts that occur in diabetes. Our findings support the hypothesis that myricetin has the potential to repair faulty skin function arising from diabetes.

T2DiACoD: A Gene Atlas of Type 2 Diabetes Mellitus Associated Complex Disorders

We performed integrative analysis of genes associated with type 2 Diabetes Mellitus (T2DM) associated complications by automated text mining with manual curation and also gene expression analysis from Gene Expression Omnibus. They were analysed for pathogenic or protective role, trends, interaction with risk factors, Gene Ontology enrichment and tissue wise differential expression. The database T2DiACoD houses 650 genes, and 34 microRNAs associated with T2DM complications. Seven genes AGER, TNFRSF11B, CRK, PON1, ADIPOQ, CRP and NOS3 are associated with all 5 complications. Several genes are studied in multiple years in all complications with high proportion in cardiovascular (75.8%) and atherosclerosis (51.3%). T2DM Patients' skeletal muscle tissues showed high fold change in differentially expressed genes. Among the differentially expressed genes, VEGFA is associated with several complications of T2DM. A few genes ACE2, ADCYAP1, HDAC4, NCF1, NFE2L2, OSM, SMAD1, TGFB1, BDNF, SYVN1, TXNIP, CD36, CYP2J2, NLRP3 with details of protective role are catalogued. Obesity is clearly a dominant risk factor interacting with the genes of T2DM complications followed by inflammation, diet and stress to variable extents. This information emerging from the integrative approach used in this work could benefit further therapeutic approaches. The T2DiACoD is available at www.http://t2diacod.igib.res.in/ .

Molecular mechanisms of AGE/RAGE-mediated fibrosis in the diabetic heart

Chronic hyperglycemia is one of the main characteristics of diabetes. Persistent exposure to elevated glucose levels has been recognized as one of the major causal factors of diabetic complications. In pathologies, like type 2 diabetes mellitus (T2DM), mechanical and biochemical stimuli activate profibrotic signaling cascades resulting in myocardial fibrosis and subsequent impaired cardiac performance due to ventricular stiffness. High levels of glucose nonenzymatically react with long-lived proteins, such as collagen, to form advanced glycation end products (AGEs). AGE-modified collagen increase matrix stiffness making it resistant to hydrolytic turnover, resulting in an accumulation of extracellular matrix (ECM) proteins. AGEs account for many of the diabetic cardiovascular complications through their engagement of the receptor for AGE (RAGE). AGE/RAGE activation stimulates the secretion of numerous profibrotic growth factors, promotes increased collagen deposition leading to tissue fibrosis, as well as increased RAGE expression. To date, the AGE/RAGE cascade is not fully understood. In this review, we will discuss one of the major fibrotic signaling pathways, the AGE/RAGE signaling cascade, as well as propose an alternate pathway via Rap1a that may offer insight into cardiovascular ECM remodeling in T2DM. In a series of studies, we demonstrate a role for Rap1a in the regulation of fibrosis and myofibroblast differentiation in isolated diabetic and non-diabetic fibroblasts. While these studies are still in a preliminary stage, inhibiting Rap1a protein expression appears to down-regulate the molecular switch used to activate the ζ isotype of protein kinase C thereby promote AGE/RAGE-mediated fibrosis.

Changes in biological behaviors of rat dermal fibroblasts induced by high expression of MMP9

BACKGROUND

The high level of matrix metalloproteinase 9 (MMP9) is thought to slow down the healing of diabetic foot ulcers. Whether it can influence the biological behaviors of skin fibroblasts and affect wound healing is still unclear. The present study aimed to observe changes in the biological behaviors of rat dermal fibroblasts induced by high expression of MMP9 and to clarify the possible mechanisms of wound healing for diabetic foot.

METHODS

A cell model of skin fibroblast with high expression of MMP9 was established by co-culture of high glucose (22.0 mmol/L) and homocysteine (100 μmol/L). A control group was incubated with normal glucose (5.5 mmol/L). Realtime PCR, ELISA and gelatin zymography were used to detect the MMP9 mRNA, protein expression and activity of MMP9. Flow cytometry, CCK-8, ELISA assay, scratch test and transwell were used to detect cell proliferation, viability, collagen (hydroxyproline) secretion, horizontal migration and vertical migration of cells. The data were expressed as mean±SD. P value less than 0.05 was considered statistically significant.

RESULTS

The expression of MMP9 mRNA, protein levels and the activity of MMP9 were much higher in the high MMP9 group than in the control group (7.05±1.02 vs. 1.00±0.00, 206.9±33.6 pg/mL vs. 40.4±5.9 pg/mL, and 1.47±0.13 vs. 0.57±0.12, respectively, P<0.01). The proportion of S-phase cells, proliferation index, cell viability, collagen (hydroxyproline) secretion, horizontal migration rate and the number of vertical migration cells were lower in the high MMP9 group than in the control group (P<0.01).

CONCLUSION

Fibroblasts with a high expression of MMP9 decreased proliferation, activity, secretion and migration of collagens, suggesting that MMP9 may inhibit the biological behaviors of fibroblasts.

Folic acid mitigates angiotensin-II-induced blood pressure and renal remodeling

Clinical data suggests an association between systolic hypertension, renal function and hyperhomocysteinemia (HHcy). HHcy is a state of elevated plasma homocysteine (Hcy) levels and is known to cause vascular complications. In this study, we tested the hypothesis whether Ang II-induced hypertension increases plasma Hcy levels and contributes to renovascular remodeling. We also tested whether folic acid (FA) treatment reduces plasma Hcy levels by enhancing Hcy remethylation and thus mitigating renal remodeling. Hypertension was induced in WT mice by infusing Ang II using Alzet mini osmotic pumps. Blood pressure, Hcy level, renal vascular density, oxidative stress, inflammation and fibrosis markers, and angiogenic- and anti-angiogenic factors were measured. Ang II hypertension increased plasma Hcy levels and reduced renal cortical blood flow and microvascular density. Elevated Hcy in Ang II hypertension was associated with decreased 4, 5-Diaminofluorescein (DAF-2DA) staining suggesting impaired endothelial function. Increased expression of Nox-2, -4 and dihydroethidium stain revealed oxidative stress. Excess collagen IV deposition in the peri-glomerular area and increased MMP-2, and -9 expression and activity indicated renal remodeling. The mRNA and protein expression of asymmetric dimethylarginine (ADMA) was increased and eNOS protein was decreased suggesting the involvement of this pathway in Hcy mediated hypertension. Decreased expressions of VEGF and increased anti-angiogenic factors, angiostatin and endostatin indicated impaired vasculogenesis. FA treatment partially reduced hypertension by mitigating HHcy in Ang II-treated animals and alleviated pro-inflammatory, pro-fibrotic and anti-angiogenic factors. These results suggest that renovascular remodeling in Ang II-induced hypertension is, in part, due to HHcy.

Cardiac fibroblast-dependent extracellular matrix accumulation is associated with diastolic stiffness in type 2 diabetes

Cardiovascular complications are a leading cause of death in patients with type 2 diabetes mellitus (T2DM). Diastolic dysfunction is one of the earliest manifestations of diabetes-induced changes in left ventricular (LV) function, and results from a reduced rate of relaxation and increased stiffness. The mechanisms responsible for increased stiffness are not completely understood. Chronic hyperglycemia, advanced glycation endproducts (AGEs), and increased levels of proinflammatory and profibrotic cytokines are molecular pathways known to be involved in regulating extracellular matrix (ECM) synthesis and accumulation resulting in increased LV diastolic stiffness. Experiments were conducted using a genetically-induced mouse model of T2DM generated by a point mutation in the leptin receptor resulting in nonfunctional leptin receptors (db/db murine model). This study correlated changes in LV ECM and stiffness with alterations in basal activation of signaling cascades and expression of profibrotic markers within primary cultures of cardiac fibroblasts from diabetic (db/db) mice with nondiabetic (db/wt) littermates as controls. Primary cultures of cardiac fibrobroblasts were maintained in 25 mM glucose (hyperglycemic-HG; diabetic db/db) media or 5 mM glucose (normoglycemic-NG, nondiabetic db/wt) media. The cells then underwent a 24-hour exposure to their opposite (NG; diabetic db/db) media or 5 mM glucose (HG, nondiabetic db/wt) media. Protein analysis demonstrated significantly increased expression of type I collagen, TIMP-2, TGF-β, PAI-1 and RAGE in diabetic db/db cells as compared to nondiabetic db/wt, independent of glucose media concentration. This pattern of protein expression was associated with increased LV collagen accumulation, myocardial stiffness and LV diastolic dysfunction. Isolated diabetic db/db fibroblasts were phenotypically distinct from nondiabetic db/wt fibroblasts and exhibited a profibrotic phenotype in normoglycemic conditions.

Inhibition of matrix metalloproteinase 9 expression in rat dermal fibroblasts using small interfering RNA

BACKGROUND

Matrix metalloproteinases (MMPs) degrade extracellular matrix components. Increased MMP-9 content in diabetic skin contributes to skin vulnerability and refractory foot ulcers. To identify ways to decrease MMP-9 levels in skin, inhibition of MMP-9 expression in dermal fibroblasts using small interfering RNA was investigated in vitro.

METHODS

A full-thickness wound was created on the midback of streptozotocin-induced diabetic rats; skin biopsies were performed 3 days later. Skin MMP-9 expression was observed by immunohistochemical analysis. Dermal fibroblasts from 1-day-old normal Sprague Dawley rats cultured with high glucose and homocysteine concentrations were transfected with small interfering RNA complexes. Cells were collected 30, 48, and 72 hours after transfection, and reverse transcription-polymerase chain reaction, Western blot analysis, and gelatin zymography for MMP-9 were performed.

RESULTS

Expression of MMP-9 was increased in diabetic rat skin, especially around wounds. After 30-, 48-, and 72-hour transfection with each MMP-9-specific small interfering RNA, reverse transcription-polymerase chain reaction showed markedly decreased MMP-9 messenger RNA expression, protein abundance, and activity. Of four MMP-9 small interfering RNAs, one sequence had a stable high inhibition rate (>70% at 30 and 48 hours after transfection).

CONCLUSIONS

Expression of MMP-9 was increased in diabetic rat skin, especially around wounds, and was markedly inhibited after MMP-9 small interfering RNA transfection in vitro (P < .05). These findings may provide new treatments for diabetic skin wounds.

Hyperhomocysteinemia is detrimental to pregnancy in mice and is associated with preterm birth

Elevated levels of homocysteine produce detrimental effects in humans but its role in preterm birth is not known. Here we used a mouse model of hyperhomocysteinemia to examine the relevance of homocysteine to preterm birth. The mouse carries a heterozygous deletion of cystathionine β-synthase (Cbs(+/-)). Gestational period was monitored in wild type and Cbs(+/-) female mice. Mouse uterine and placental tissues, human primary trophoblast cells, and human myometrial and placental cell lines were used to determine the influence of homocysteine on expression of specific genes in vitro. The activity of BKCa channel in the myometrial cell line was monitored using the patch-clamp technique. We found that hyperhomocysteinemia had detrimental effects on pregnancy and induced preterm birth in mice. Homocysteine increased the expression of oxytocin receptor and Cox-2 as well as PGE2 production in uterus and placenta, and initiated premature uterine contraction. A Cox-2 inhibitor reversed these effects. Gpr109a, a receptor for niacin, induced Cox-2 in uterus. Homocysteine upregulated GPR109A and suppressed BKCa channel activity in human myometrial cells. Deletion of Gpr109a in Cbs(+/-) mice reversed premature birth. We conclude that hyperhomocysteinemia causes preterm birth in mice through upregulation of the Gpr109a/Cox-2/PGE2 axis and that pharmacological blockade of Gpr109a may have potential in prevention of preterm birth.

The biological behaviors of rat dermal fibroblasts can be inhibited by high levels of MMP9

Aims. To explore the effects of the high expression of MMP9 on biological behaviors of fibroblasts. Methods. High glucose and hyperhomocysteine were used to induce MMP9 expression in skin fibroblasts. Cell proliferation was detected by flow cytometry and cell viability by CCK-8. ELISA assay was used to detect collagen (hydroxyproline) secretion. Scratch test was employed to evaluate horizontal migration of cells and transwell method to evaluate vertical migration of cells. Results. The mRNA and protein expressions of MMP9 and its protease activity were significantly higher in cells treated with high glucose and hyperhomocysteine than those in control group. At the same time, the S-phase cell ratio, proliferation index, cell viability, collagen (hydroxyproline) secretion, horizontal migration rate, and the number of vertical migration cells decreased in high-glucose and hyperhomocysteine-treated group. Tissue inhibitor of metalloproteinase 1 (TIMP1), which inhibits the activity of MMP9, recovered the above biological behaviors. Conclusions. High expression of MMP9 in skin fibroblasts could be induced by cultureing in high glucose and hyperhomocysteine medium, which inhibited cell biological behaviors. Inhibitions could be reversed by TIMP1. The findings suggested that MMP9 deters the healing of diabetic foot ulcers by inhibiting the biological behaviors of fibroblasts.

Synergism in hyperhomocysteinemia and diabetes: role of PPAR gamma and tempol

BACKGROUND

Hyperhomocysteinemia (HHcy) and hyperglycemia cause diabetic cardiomyopathy by inducing oxidative stress and attenuating peroxisome proliferator- activated receptor (PPAR) gamma. However, their synergistic contribution is not clear.

METHODS

Diabetic Akita (Ins2+/-) and hyperhomocysteinemic cystathionine beta synthase mutant (CBS+/-) were used for M-mode echocardiography at the age of four and twenty four weeks. The cardiac rings from WT, Akita and hybrid (Ins2+/-/CBS+/-) of Akita and CBS+/- were treated with different doses of acetylcholine (an endothelial dependent vasodilator). High performance liquid chromatography (HPLC) was performed for determining plasma homocysteine (Hcy) level in the above groups. Akita was treated with ciglitazone (CZ) - a PPAR gamma agonist and tempol-an anti-oxidant, separately and their effects on cardiac remodeling were assessed.

RESULTS

At twenty four week, Akita mice were hyperglycemic and HHcy. They have increased end diastolic diameter (EDD). In their heart PPAR gamma, tissue inhibitor of metalloproteinase-4 (TIMP-4) and anti-oxidant thioredoxin were attenuated whereas matrix metalloproteinase (MMP)-9, TIMP-3 and NADPH oxidase 4 (NOX4) were induced. Interestingly, they showed synergism between HHcy and hyperglycemia for endothelial-myocyte (E-M) uncoupling. Additionally, treatment with CZ alleviated MMP-9 activity and fibrosis, and improved EDD. On the other hand, treatment with tempol reversed cardiac remodeling in part by restoring the expressions of TIMP-3,-4, thioredoxin and MMP-9.

CONCLUSIONS

Endogenous homocysteine exacerbates diabetic cardiomyopathy by attenuating PPAR gamma and inducing E-M uncoupling leading to diastolic dysfunction. PPAR gamma agonist and tempol mitigates oxidative stress and ameliorates diastolic dysfunction in diabetes.

Diabetes is associated with increased sensitivity of alveolar macrophages to urban particulate matter exposure

Many epidemiological studies and animal experiments have shown that individuals with preexisting diseases, such as asthma, chronic obstructive pulmonary disease (COPD), and diabetes mellitus (DM) are more susceptible to particulate matter (PM)-related health problems. However, the mechanisms underlying this susceptibility are still unclear. PM has been shown to affect macrophage functions. We hypothesized that exposure to PM in the setting of DM and high glucose levels would result in enhanced macrophage activation. Rabbits were rendered diabetic with alloxan administered intravenously. Blood glucose concentration was measured daily for the first several weeks and weekly thereafter using a blood glucose meter. After 9 months of diabetes (blood glucose great than 450mg/dl), rabbits were sacrificed and bronchoalveolar lavage was performed to collect alveolar macrophages. Alveolar macrophages were exposed in vitro to urban particulate matter SRM 1648 (U-PM). Our results showed that U-PM caused dose-dependent cytotoxic effects, and these effects were significantly higher in macrophages obtained from DM rabbits than those from normal rabbits. Reactive oxygen species (ROS) generation in macrophages from DM rabbits with exposure to U-PM was also greater than in macrophages from normal rabbits. Our results also showed that exposure of macrophages to U-PM caused an increase in cytokine mRNA expression level and activity of matrix metalloproteinase 9 (MMP-9), but not MMP-2, and that these effects were greater in macrophages from DM rabbits. These results demonstrate that U-PM caused severe oxidative stress in macrophages from DM rabbits and up-regulation of cytokine expression and MMP-9 activity.

Cytochrome P450 (CYP) 2J2 gene transfection attenuates MMP-9 via inhibition of NF-kappabeta in hyperhomocysteinemia

Hyperhomocysteinemia (HHcy) is associated with atherosclerotic events involving the modulation of arachidonic acid (AA) metabolism and the activation of matrix metalloproteinase-9 (MMP-9). Cytochrome P450 (CYP) epoxygenase-2J2 (CYP2J2) is abundant in the heart endothelium, and its AA metabolites epoxyeicosatrienoic acids (EETs) mitigates inflammation through NF-kappabeta. However, the underlying molecular mechanisms for MMP-9 regulation by CYP2J2 in HHcy remain obscure. We sought to determine the molecular mechanisms by which P450 epoxygenase gene transfection or EETs supplementation attenuate homocysteine (Hcy)-induced MMP-9 activation. CYP2J2 was over-expressed in mouse aortic endothelial cells (MAECs) by transfection with the pcDNA3.1/CYP2J2 vector. The effects of P450 epoxygenase transfection or exogenous supplementation of EETs on NF-kappabeta-mediated MMP-9 regulation were evaluated using Western blot, in-gel gelatin zymography, electromobility shift assay, immunocytochemistry. The result suggested that Hcy downregulated CYP2J2 protein expression and dephosphorylated PI3K-dependent AKT signal. Hcy induced the nuclear translocation of NF-kappabeta via downregulation of IKbetaalpha (endogenous cytoplasmic inhibitor of NF-kappabeta). Hcy induced MMP-9 activation by increasing NF-kappabeta-DNA binding. Moreover, P450 epoxygenase transfection or exogenous addition of 8,9-EET phosphorylated the AKT and attenuated Hcy-induced MMP-9 activation. This occurred, in part, by the inhibition of NF-kappabeta nuclear translocation, NF-kappabeta-DNA binding and activation of IKbetaalpha. The study unequivocally suggested the pivotal role of EETs in the modulation of Hcy/MMP-9 signal.

Mechanistic exploration of phthalimide neovascular factor 1 using network analysis tools

Neovascularization is essential for the survival and successful integration of most engineering tissues after implantation in vivo. The objective of this study was to elucidate possible mechanisms of phthalimide neovascular factor 1 (PNF1), a new synthetic small molecule proposed for therapeutic induction of angiogenesis. Complementary deoxyribonucleic acid microarray analysis was used to identify 568 transcripts in human microvascular endothelial cells (HMVECs) that were significantly regulated after 24-h stimulation with 30 muM of PNF1, previously known as SC-3-149. Network analysis tools were used to identify genetic networks of the global biological processes involved in PNF1 stimulation and to describe known molecular and cellular functions that the drug regulated most highly. Examination of the most significantly perturbed networks identified gene products associated with transforming growth factor-beta (TGF-beta), which has many known effects on angiogenesis, and related signal transduction pathways. These include molecules integral to the thrombospondin, plasminogen, fibroblast growth factor, epidermal growth factor, ephrin, Rho, and Ras signaling pathways that are essential to endothelial function. Moreover, real-time reverse-transcriptase polymerase chain reaction (RT-PCR) of select genes showed significant increases in TGF-beta-associated receptors endoglin and beta glycan. These experiments provide important insight into the pro-angiogenic mechanism of PNF1, namely, TGF-beta-associated signaling pathways, and may ultimately offer new molecular targets for directed drug discovery.

Cardiac synchronous and dys-synchronous remodeling in diabetes mellitus

Glucose-mediated impairment of homocysteine (Hcy) metabolism and decrease in renal clearance contribute to hyperhomocysteinemia (HHcy) in diabetes. The Hcy induces oxidative stress, inversely relates to the expression of peroxisome proliferators activated receptor (PPAR), and contributes to diabetic complications. Extracellular matrix (ECM) functionally links the endothelium to the myocyte and is important for cardiac synchronization. However, in diabetes and hyperhomocysteinemia, a "disconnection" is caused by activated matrix metalloproteinase with subsequent accumulation of oxidized matrix (fibrosis) between the endothelium and myocyte (E-M). This contributes to "endothelial-myocyte uncoupling," attenuation of cardiac synchrony, leading to diastolic heart failure (DHF), and cardiac dys-synchronizatrion. The decreased levels of thioredoxin and peroxiredoxin and cardiac tissue inhibitor of metalloproteinase are in response to antagonizing PPARgamma.