COVID-19 Associated Cardiovascular Disease-Risks, Prevention and Management: Heart at Risk Due to COVID-19

The SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus-2) virus and the resulting COVID-19 pandemic have had devastating and lasting impact on the global population. Although the main target of the disease is the respiratory tract, clinical outcomes, and research have also shown significant effects of infection on other organ systems. Of interest in this review is the effect of the virus on the cardiovascular system. Complications, including hyperinflammatory syndrome, myocarditis, and cardiac failure, have been documented in the context of COVID-19 infection. These complications ultimately contribute to worse patient outcomes, especially in patients with pre-existing conditions such as hypertension, diabetes, or cardiovascular disease (CVD). Importantly and interestingly, reports have demonstrated that COVID-19 also causes myocardial injury in adults without pre-existing conditions and contributes to systemic complications in pediatric populations, such as the development of multisystem inflammatory syndrome in children (MIS-C). Although there is still a debate over the exact mechanisms by which such complications arise, understanding the potential paths by which the virus can influence the cardiovascular system to create an inflammatory environment may clarify how SARS-CoV-2 interacts with human physiology. In addition to describing the mechanisms of disease propagation and patient presentation, this review discusses the diagnostic findings and treatment strategies and the evolution of management for patients presenting with cardiovascular complications, focusing on disease treatment and prevention.

Novel approaches to determine the functional role of cardiomyocyte specific E3 ligase, Pellino-1 following myocardial infarction

OBJECTIVES

Ubiquitination plays a vital role in controlling vascular inflammation, cellular protein quality control, and minimizing misfolded protein toxicity. Pellino-1 (Peli1), a type of E3 ubiquitin ligase, has emerged as a critical regulator of the innate immune response; however, its role in the repair and regeneration of ischemic myocardium remains to be elucidated.

METHODS

Mice (8-12 weeks old, male and females) were divided into (i) Wild type (ii) cardiomyocyte-specific Peli1 overexpressed (AMPEL1Tg/+), (iii) cardiomyocyte-specific Peli1 knockout (CP1KO) and were subjected to sham and left anterior descending artery ligation. The tissues were collected at various time points after surgery for Western blot, and immunohistochemical analyses. Echocardiography is performed 30 days after myocardial infarction. Cardiomyocytes isolated from wild-type, Peli1 overexpressed and knockout mice were used to study the interaction between cardiomyocytes and endothelial cells in vitro under oxidative stress and cells were used for Western blot, flow cytometric analysis, and scratch assay.

RESULTS

We observed faster wound closure and increased expression of angiogenic factors with MCECs treated with conditioned media obtained from the AMPEL1Tg/+ cardiomyocytes compared to CPIKO and WT cardiomyocytes. Again, AMPEL1Tg/+MI mice showed preserved systolic function and reduced fibrosis compared to the CPIKOMI and WTMI groups. Capillary and arteriolar density were found to be increased in AMPEL1Tg/+MI compared to CP1KOMI. Increased survival and angiogenic factors such as p-Akt, p-MK2, p-IkBα, VEGF, cIAP2, and Bcl2 were observed in AMPEL1Tg/+ compared to CP1KO and WT mice subjected to MI.

CONCLUSION

The present study uncovers the crucial role of cardiac Peli1 as a regulator of the repair and regeneration of ischemic myocardium by using multiple genetically engineered mouse models.

Biodegradable piezoelectric skin-wound scaffold

Electrical stimulation (ES) induces wound healing and skin regeneration. Combining ES with the tissue-engineering approach, which relies on biomaterials to construct a replacement tissue graft, could offer a self-stimulated scaffold to heal skin-wounds without using potentially toxic growth factors and exogenous cells. Unfortunately, current ES technologies are either ineffective (external stimulations) or unsafe (implanted electrical devices using toxic batteries). Hence, we propose a novel wound-healing strategy that integrates ES with tissue engineering techniques by utilizing a biodegradable self-charged piezoelectric PLLA (Poly (l-lactic acid)) nanofiber matrix. This unique, safe, and stable piezoelectric scaffold can be activated by an external ultrasound (US) to produce well-controlled surface-charges with different polarities, thus serving multiple functions to suppress bacterial growth (negative surface charge) and promote skin regeneration (positive surface charge) at the same time. We demonstrate that the scaffold activated by low intensity/low frequency US can facilitate the proliferation of fibroblast/epithelial cells, enhance expression of genes (collagen I, III, and fibronectin) typical for the wound healing process, and suppress the growth of S. aureus and P. aeruginosa bacteria in vitro simultaneously. This approach induces rapid skin regeneration in a critical-sized skin wound mouse model in vivo. The piezoelectric PLLA skin scaffold thus assumes the role of a multi-tasking, biodegradable, battery-free electrical stimulator which is important for skin-wound healing and bacterial infection prevention simultaneuosly.

Role of Pellino-1 in Inflammation and Cardioprotection following Severe Sepsis: A Novel Mechanism in a Murine Severe Sepsis Model †

OBJECTIVES

Intra-abdominal sepsis is commonly diagnosed in the surgical population and remains the second most common cause of sepsis overall. Sepsis-related mortality remains a significant burden in the intensive care unit despite advances in critical care. Nearly a quarter of the deaths in people with heart failure are caused by sepsis. We have observed that overexpression of mammalian Pellino-1 (Peli1), an E3 ubiquitin ligase, causes inhibition of apoptosis, oxidative stress, and preservation of cardiac function in a myocardial infarction model. Given these manifold applications, we investigated the role of Peli1 in sepsis using transgenic and knockout mouse models specific to this protein. Therefore, we aimed to explore further the myocardial dysfunction seen in sepsis through its relation to the Peli 1 protein by using the loss of function and gain-of-function strategy.

METHODS

A series of genetic animals were created to understand the role of Peli1 in sepsis and the preservation of heart function. Wild-type, global Peli1 knock out (Peli1-/-), cardiomyocyte-specific Peli1 deletion (CP1KO), and cardiomyocyte-specific Peli1 overexpressing (alpha MHC (αMHC) Peli1; AMPEL1Tg/+) animals were divided into sham and cecal ligation and puncture (CLP) surgical procedure groups. Cardiac function was determined by two-dimensional echocardiography pre-surgery and at 6- and 24-h post-surgery. Serum IL-6 and TNF-alpha levels (ELISA) (6 h), cardiac apoptosis (TUNEL assay), and Bax expression (24 h) post-surgery were measured. Results are expressed as mean ± S.E.M.

RESULTS

AMPEL1Tg/+ prevents sepsis-induced cardiac dysfunction assessed by echocardiographic analysis, whereas global and cardiomyocyte-specific deletion of Peli1 shows significant deterioration of cardiac functions. Cardiac function was similar across the sham groups in all three genetically modified mice. ELISA assay displayed how Peli 1 overexpression decreased cardo-suppressive circulating inflammatory cytokines (TNF-alpha, IL-6) compared to both the knockout groups. The proportion of TUNEL-positive cells varied according to Peli1 expression, with overexpression (AMPEL1Tg/+) leading to a significant reduction and Peli1 gene knockout (Peli1-/- and CP1KO) leading to a significant increase in their presence. A similar trend was also observed with Bax protein expression. The improved cellular survival associated with Peli1 overexpression was again shown with the reduction of oxidative stress marker 4-Hydroxy-2-Nonenal (4-HNE).

CONCLUSION

Our results indicate that overexpression of Peli1 is a novel approach that not only preserved cardiac function but reduced inflammatory markers and apoptosis following severe sepsis in a murine genetic model.

Driving adult tissue repair via re-engagement of a pathway required for fetal healing

Fetal cutaneous wound closure and repair differ from that in adulthood. In this work, we identify an oxidant stress sensor protein, nonselenocysteine-containing phospholipid hydroperoxide glutathione peroxidase (NPGPx), that is abundantly expressed in normal fetal epidermis (and required for fetal wound closure), though not in adult epidermis, but is variably re-induced upon adult tissue wounding. NPGPx is a direct target of the miR-29 family. Following injury, abundance of miR-29 is lowered, permitting a prompt increase in NPGPx transcripts and protein expression in adult wound-edge tissue. NPGPx expression was required to mediate increased keratinocyte migration induced by miR-29 inhibition in vitro and in vivo. Increased NPGPx expression induced increased SOX2 expression and β-catenin nuclear localization in keratinocytes. Augmenting physiologic NPGPx expression via experimentally induced miR-29 suppression, using cutaneous tissue nanotransfection or targeted lipid nanoparticle delivery of anti-sense oligonucleotides, proved to be sufficient to overcome the deleterious effects of diabetes on this specific pathway to enhance tissue repair.

Gene therapy with Pellino-1 improves perfusion and decreases tissue loss in Flk-1 heterozygous mice but fails in MAPKAP Kinase-2 knockout murine hind limb ischemia model

OBJECTIVES

In the United States, over 8.5 million people suffer from peripheral arterial disease (PAD). Previously we reported that Pellino-1(Peli1) gene therapy reduces ischemic damage in the myocardium and skin flaps in Flk-1 [Fetal Liver kinase receptor-1 (Flk-1)/ Vascular endothelial growth factor receptor-2/VEGFR2] heterozygous (Flk-1^+/-) mice. The present study compares the angiogenic response and perfusion efficiency following hind limb ischemia (HLI) in, Flk-1^+/- and, MAPKAPKINASE2 (MK2^-/-) knockout (KO) mice to their control wild type (WT). We also demonstrated the use of Peli1 gene therapy to improve loss of function following HLI.

STUDY DESIGN AND METHODS

Femoral artery ligation (HLI) was performed in both Flk-1^+/-and MK2^-/-mice along with their corresponding WT. Another set of Flk-1^+/- and MK2^-/- were injected with either Adeno-LacZ (Ad.LacZ) or Adeno-Peli1 (Ad.Peli1) after HLI. Hind limb perfusion was assessed by laser doppler imaging at specific time points. A standardized scoring scale is used to quantify the extent of ischemia. Histology analysis performed includes capillary density, fibrosis, pro-angiogenic and anti-apoptotic proteins.

RESULTS

Flk-1^+/- and MK2^-/- had a slower recovery of perfusion efficiency in the ischemic limbs than controls. Both Flk-1^+/-and MK2^-/-KO mice showed decreased capillary density and capillary myocyte ratios with increased fibrosis than their corresponding wild types. Ad.Peli1 injected ischemic Flk-1^+/- limb showed improved perfusion, increased capillary density, and pro-angiogenic molecules with reduced fibrosis compared to Ad.LacZ group. No significant improvement in perfusion was observed in MK2^-/- ischemic limb after Ad. Peli1 injection.

CONCLUSION

Deletion of Flk-1 and MK2 impairs neovascularization and perfusion following HLI. Treatment with Ad. Peli1 results in increased angiogenesis and improved perfusion in Flk-1^+/- mice but fails to rectify perfusion in MK2 KO mice. Overall, Peli1 gene therapy is a promising candidate for the treatment of PAD.

Disruption of VEGF Mediated Flk-1 Signaling Leads to a Gradual Loss of Vessel Health and Cardiac Function During Myocardial Infarction: Potential Therapy With Pellino-1

Background

The present study demonstrates that the ubiquitin E3 ligase, Pellino‐1 (Peli1), is an important angiogenic molecule under the control of vascular endothelial growth factor (VEGF) receptor 2/Flk‐1. We have previously reported increased survivability of ischemic skin flap tissue by adenovirus carrying Peli1 (Ad‐Peli1) gene therapy in Flk‐1^+/− mice.

Methods and Results

Two separate experimental groups of mice were subjected to myocardial infarction (MI) followed by the immediate intramyocardial injection of adenovirus carrying LacZ (Ad‐LacZ) (1×10⁹ pfu) or Ad‐Peli1 (1×10⁹ pfu). Heart tissues were collected for analyses. Compared with wild‐type (WTMI) mice, analysis revealed decreased expressions of Peli1, phosphorylated (p‐)Flk‐1, p‐Akt, p‐eNOS, p‐MK2, p‐IκBα, and NF‐κB and decreased vessel densities in Flk‐1^+/− mice subjected to MI (Flk‐1^+/−MI). Mice (CD1) treated with Ad‐Peli1 after the induction of MI showed increased β‐catenin translocation to the nucleus, connexin 43 expression, and phosphorylation of Akt, eNOS, MK2, and IκBα, that was followed by increased vessel densities compared with the Ad‐LacZ–treated group. Echocardiography conducted 30 days after surgery showed decreased function in the Flk1^+/−MI group compared with WTMI, which was restored by Ad‐Peli1 gene therapy. In addition, therapy with Ad‐Peli1 stimulated angiogenic and arteriogenic responses in both CD1 and Flk‐1^+/− mice following MI. Ad‐Peli1 treatment attenuated cardiac fibrosis in Flk‐1^+/−MI mice. Similar positive results were observed in CD1 mice subjected to MI after Ad‐Peli1 therapy.

Conclusion

Our results show for the first time that Peli1 plays a unique role in salvaging impaired collateral blood vessel formation, diminishes fibrosis, and improves myocardial function, thereby offering clinical potential for therapies in humans to mend a damaged heart following MI.

Thioredoxin-1 confines T cell alloresponse and pathogenicity in graft-versus-host disease

Oxidative stress is elevated in the recipients of allogeneic hematopoietic transplantation (allo-HCT) and likely contributes to the development of graft-versus-host disease (GVHD). GVHD is characterized by activation, expansion, cytokine production and migration of alloreactive donor T cells, and remains a major cause of morbidity and mortality after allo-HCT. Hence, strategies to limit oxidative stress in GVHD are highly desirable. Thioredoxin1 (Trx1) counteracts oxidative stress by scavenging reactive oxygen species (ROS) and regulating other enzymes that metabolize H2O2. The present study sought to elucidate the role of Trx1 in the pathophysiology of GVHD. Using murine and xenograft models of allogeneic bone marrow transplantation (allo-BMT) and genetic (human Trx1-transgenic, Trx1-Tg) as well as pharmacologic (human recombinant Trx1, RTrx1) strategies; we found that Trx1-Tg donor T cells or administration of the recipients with RTrx1 significantly reduced GVHD severity. Mechanistically, we observed RTrx1 reduced ROS accumulation and cytokine production of mouse and human T cells in response to alloantigen stimulation in vitro. In allo-BMT settings, we found that Trx1-Tg or RTrx1 decreased downstream signaling molecules including NFκB activation and T-bet expression, and reduced proliferation, IFN-γ production and ROS accumulation in donor T cells within GVHD target organs. More importantly, administration of RTrx1 did not impair the graft-versus-leukemia (GVL) effect. Taken together, the current work provides a strong rationale and demonstrates feasibility to target the ROS pathway, which can be readily translated into clinic.

Thioredoxin-1 improves the immunometabolic phenotype of antitumor T cells

Adoptive transfer of tumor epitope-reactive T cells has emerged as a promising strategy to control tumor growth. However, chronically-stimulated T cells expanded for adoptive cell transfer are susceptible to cell death in an oxidative tumor microenvironment. Because oxidation of cell-surface thiols also alters protein functionality, we hypothesized that increasing the levels of thioredoxin (Trx), an antioxidant molecule facilitating reduction of proteins through cysteine thiol-disulfide exchange, in T cells will promote their sustained antitumor function. Using pre-melanosome protein (Pmel)-Trx1 transgenic mouse-derived splenic T cells, flow cytometry, and gene expression analysis, we observed here that higher Trx expression inversely correlated with reactive oxygen species and susceptibility to T-cell receptor restimulation or oxidation-mediated cell death. These Trx1-overexpressing T cells exhibited a cluster of differentiation 62L^hi (CD62L^hi) central memory-like phenotype with reduced glucose uptake (2-NBDG^lo) and decreased effector function (interferon γ^lo). Furthermore, culturing tumor-reactive T cells in the presence of recombinant Trx increased the dependence of T cells on mitochondrial metabolism and improved tumor control. We conclude that strategies for increasing the antioxidant capacity of antitumor T cells modulate their immunometabolic phenotype leading to improved immunotherapeutic control of established tumors.

Graphene-based drug delivery systems in tissue engineering and nanomedicine

The time and dosage form of graphene derivatives have been found to determine therapeutic and toxic windows in several cell lines and preclinical models. The enhanced biological action of graphene derivatives is made possible by altering the chemistry of native materials via surface conjugation, or by changing the oxidation state. The high level of chemical reactivity vested in the planar structure of graphene can be used to load various drugs and biomolecules with maximum radical scavenging effect. The integration of graphene and polymers brings electrical conductivity to scaffolds, making them ideal for cardiac or neuronal tissue engineering. Drawbacks associated with graphene-based materials for biomedical applications include defect-free graphene formation and heteroatom contamination during synthesis process; reduced availability of sp² hybridized carbon centers due to serum proteins masking; and poor availability of data pertaining to in vivo clearance of graphene-based formulations. Personalized medicine is an emerging area of alternative treatments, which in combination with graphene-based nanobiomaterials, has revolutionary potential for the development of individualized nanocarriers to treat highly challenging diseases.

Graphene-based drug delivery systems in tissue engineering and nanomedicine

The time and dosage form of graphene derivatives have been found to determine therapeutic and toxic windows in several cell lines and preclinical models. The enhanced biological action of graphene derivatives is made possible by altering the chemistry of native materials via surface conjugation, or by changing the oxidation state. The high level of chemical reactivity vested in the planar structure of graphene can be used to load various drugs and biomolecules with maximum radical scavenging effect. The integration of graphene and polymers brings electrical conductivity to scaffolds, making them ideal for cardiac or neuronal tissue engineering. Drawbacks associated with graphene-based materials for biomedical applications include defect-free graphene formation and heteroatom contamination during synthesis process; reduced availability of sp² hybridized carbon centers due to serum proteins masking; and poor availability of data pertaining to in vivo clearance of graphene-based formulations. Personalized medicine is an emerging area of alternative treatments, which in combination with graphene-based nanobiomaterials, has revolutionary potential for the development of individualized nanocarriers to treat highly challenging diseases.

Thioredoxin-1 augments wound healing and promote angiogenesis in a murine ischemic full-thickness wound model

BACKGROUND

Nonhealing wounds are a continuing health problem in the United States. Overproduction of reactive oxygen species is a major causative factor behind delayed wound healing. Previously we reported that thioredoxin-1 treatment could alleviate oxidative stress under ischemic conditions, such as myocardial infarction and hindlimb ischemia. In this study, we explored the potential for thioredoxin-1 gene therapy to effectively aid wound healing through improved angiogenesis in a murine ischemic wound model.

METHODS

Full-thickness, cutaneous, ischemic wounds were created in the dorsum skin flap of 8- to 12-week-old CD1 mice. Nonischemic wounds created lateral to the ischemic skin flap served as internal controls. Mice with both ischemic wounds and nonischemic wounds were treated with Adeno-LacZ (1 × 10⁹ pfu) or Adeno-thioredoxin-1 (1 × 10⁹ pfu), injected intradermally around the wound. Digital imaging was performed on days 0, 3, 6, and 9 to assess the rate of wound closure. Tissue samples collected at predetermined time intervals were processed for immunohistochemical analysis.

RESULTS

No significant differences in wound closure were identified among the nonischemic wounds control, nonischemic wounds-LacZ, and nonischemic wounds-thioredoxin-1 groups. Hence, only mice with ischemic wounds were further analyzed. The ischemic wounds-thioredoxin-1 group had significant improvement in wound closure on days 6 and 9 after surgery compared with the ischemic wounds control and ischemic wounds-LacZ groups. Immunohistochemical analysis indicated increased thioredoxin-1, vascular endothelial cell growth factor, and β-catenin levels in the ischemic wounds-thioredoxin-1 group compared with the ischemic wounds control and ischemic wounds-LacZ groups, as well as increased capillary density and cell proliferation, as represented by Ki-67 staining.

CONCLUSION

Taken together, thioredoxin-1 gene therapy promotes vascular endothelial cell growth factor signaling and re-epithelialization and activates wound closure in mice with ischemic wounds.

Increased survivability of ischemic skin flap tissue in Flk-1+/- mice by Pellino-1 intervention

OBJECTIVE

Reduced skin flap survival due to ischemia is a serious concern during reconstructive cosmetic surgery. The absence of VEGF and its receptors during ischemia may lead to flap failure. We identified Peli1, a 46-kDa protein, as a proangiogenic molecule and is directly regulated by VEGF. Therefore, we hypothesized that Peli1 acts downstream of Flk-1/VEGFR2 and aids in skin flap survival during ischemia.

METHODS

Scratch and matrigel assays were performed to observe cell proliferation, migration, and tube formation in vitro. Western blot analysis was carried out to detect the phosphorylation of Akt (p-Akt) and MAPKAPK2 (p-MK2) in HUVECs. The translational potential of Peli1 pretreatment in the rescue of skin flap tissue was studied in vivo using Flk-1^+/- mice. Animals underwent dorsal ischemic skin flap surgery, and the tissue was collected on day 12 for analysis.

RESULTS

Western blot analysis revealed a direct relationship between Peli1 and VEGF, as demonstrated by loss-of-function and gain-of-function studies. In addition, pretreatment with Ad.Peli1 restored the phosphorylation of Akt and MK2 and improved the migration potential of Flk-1-knockdown cells. Ad.Peli1 pretreatment salvaged the ischemic skin flap of Flk-1^+/- mice by increasing blood perfusion and reducing the inflammatory response and the extent of necrosis.

CONCLUSION

Our findings reveal that Peli1 is a proangiogenic molecule that acts downstream of VEGF-Flk-1 and restores angiogenesis and enhances skin flap survivability.

Thioredoxin-1 attenuates sepsis-induced cardiomyopathy after cecal ligation and puncture in mice

BACKGROUND

Sepsis is a leading cause of mortality among patients in intensive care units across the USA. Thioredoxin-1 (Trx-1) is an essential 12 kDa cytosolic protein that, apart from maintaining the cellular redox state, possesses multifunctional properties. In this study, we explored the possibility of controlling adverse myocardial depression by overexpression of Trx-1 in a mouse model of severe sepsis.

METHODS

Adult C57BL/6J and Trx-1Tg/+ mice were divided into wild-type sham (WTS), wild-type cecal ligation and puncture (WTCLP), Trx-1Tg/+sham (Trx-1Tg/+S), and Trx-1Tg/+CLP groups. Cardiac function was evaluated before surgery, 6 and 24 hours after CLP surgery. Immunohistochemical and Western blot analysis were performed after 24 hours in heart tissue sections.

RESULTS

Echocardiography analysis showed preserved cardiac function in the Trx-1Tg/+ CLP group compared with the WTCLP group. Similarly, Western blot analysis revealed increased expression of Trx-1, heme oxygenase-1 (HO-1), survivin (an inhibitor of apoptosis [IAP] protein family), and decreased expression of thioredoxin-interacting protein (TXNIP), caspase-3, and 3- nitrotyrosine in the Trx-1Tg/+CLP group compared with the WTCLP group. Immunohistochemical analysis showed reduced 4-hydroxynonenal, apoptosis, and vascular leakage in the cardiac tissue of Trx-1Tg/+CLP mice compared with mice in the WTCLP group.

CONCLUSIONS

Our results indicate that overexpression of Trx-1 attenuates cardiac dysfunction during CLP. The mechanism of action may involve reduction of oxidative stress, apoptosis, and vascular permeability through activation of Trx-1/HO-1 and anti-apoptotic protein survivin.

Trimodal rescue of hind limb ischemia with growth factors, cells, and nanocarriers: fundamentals to clinical trials

Peripheral artery disease is a severe medical condition commonly characterized by critical or acute limb ischemia. Gradual accumulation of thrombotic plaques in peripheral arteries of the lower limb may lead to intermittent claudication or ischemia in muscle tissue. Ischemic muscle tissue with lesions may become infected, resulting in a non-healing wound. Stable progression of the non-healing wound associated with severe ischemia might lead to functional deterioration of the limb, which, depending on the severity, can result in amputation. Immediate rescue of ischemic muscles through revascularization strategies is considered the gold standard to treat critical limb ischemia. Growth factors offer multiple levels of protection in revascularization of ischemic tissue. In this review, the basic mechanism through which growth factors exert their beneficial properties to rescue the ischemic limb is extensively discussed. Moreover, clinical trials based on growth factor and stem cell therapy to treat critical limb ischemia are considered. The clinical utility of stem cell therapy for the treatment of limb ischemia is explained and recent advances in nanocarrier technology for selective growth factor and stem cell supplementation are summarized.

Regulation of A-Kinase-Anchoring Protein 12 by Heat Shock Protein A12B to Prevent Ventricular Dysfunction Following Acute Myocardial Infarction in Diabetic Rats

We examined the effects of overexpressing HSPA12B on angiogenesis and myocardial function by intramyocardial administration of adenovirus encoding HSPA12B (Ad. HSPA12B) in a streptozotocin-induced diabetic rat subjected to myocardial infarction. Rats were divided randomly into six groups: control sham (CS) + Ad.LacZ, control myocardial infarction (CMI) + Ad.LacZ, control MI + Ad.HSPA12B, diabetic sham (DS) + Ad.LacZ, diabetic MI + Ad.LacZ and diabetic MI + Ad.HSPA12B. Following MI or sham surgery, the respective groups received either Ad.LacZ or Ad.HSPA12B via intramyocardial injections. We observed increased capillary and arteriolar density along with reduced fibrosis and preserved heart functions in DMI-AdHSPA12B compared to DMI-AdLacZ group. Western blot analysis demonstrated enhanced HSPA12B, vascular endothelial growth factor (VEGF), thioredoxin-1 (Trx-1) expression along with decreased expression of thioredoxin interacting protein (TXNIP) and A kinase anchoring protein 12 (AKAP12) in the DMI-AdHSPA12B compared to DMI-AdLacZ group. Our findings reveal that HSPA12B overexpression interacts with AKAP12 and downregulate TXNIP in diabetic rats following acute MI.

Thioredoxin-1 (Trx1) engineered mesenchymal stem cell therapy increased pro-angiogenic factors, reduced fibrosis and improved heart function in the infarcted rat myocardium

INTRODUCTION

Engraftment of mesenchymal stem cells (MSCs) has emerged as a powerful candidate for mediating myocardial repair. In this study, we genetically modified MSCs with an adenovector encoding thioredoxin-1 (Ad.Trx1). Trx1 has been described as a growth regulator, a transcription factor regulator, a cofactor, and a powerful antioxidant. We explored whether engineered MSCs, when transplanted, are capable of improving cardiac function and angiogenesis in a rat model of myocardial infarction (MI).

METHODS

Rat MSCs were cultured and divided into MSC, MSC+Ad.LacZ, and MSC+Ad.Trx1 groups. The cells were assayed for proliferation, and differentiation potential. In addition, rats were divided into control-sham (CS), control-MI (CMI), MSC+Ad.LacZ-MI (MLZMI), and MSC+Ad.Trx1-MI (MTrxMI) groups. MI was induced by left anterior descending coronary artery (LAD) ligation, and MSCs preconditioned with either Ad.LacZ or Ad.Trx1 were immediately administered to four sites in the peri-infarct zone.

RESULTS

The MSC+Ad.Trx1 cells increased the proliferation capacity and maintained pluripotency, allowing them to divide into cardiomyocytes, smooth muscle, and endothelial cells. Western blot analysis, 4 days after treatment showed increased vascular endothelial growth factor (VEGF), heme oxygenase-1 (HO-1), and C-X-C chemokine receptor type 4 (CXCR4). Also capillary density along with myocardial function as examined by echocardiography was found to be increased. Fibrosis was reduced in the MTrxMI group compared to MLZMI and CMI. Visualization of Connexin-43 by immunohistochemistry confirmed increased intercellular connections in the MTrxMI rats compared to MLZMI.

CONCLUSION

Engineering MSCs to express Trx1 may prove to be a strategic therapeutic modality in the treatment of cardiac failure.

Thioredoxins in cardiovascular disease

Key thioredoxin (Trx) system components are nicotinamide adenine dinucleotide phosphate (NADPH), Trx reductase (TrxR), and Trx. TrxR catalyzes disulfide reduction in Trx with NADPH as cofactor. Because Trx is an antioxidant, oxidative stress results in an increase in Trx, which has a reduced disulfide component. If Trx is suppressed, oxidative stress in higher. In contrast a decrease in oxidative stress is associated with low Trx levels. Trx is involved in inflammation, apoptosis, embryogenesis, and cardiovascular disease (CVD). This review focuses on the Trx system in CVD. Abnormal Trx binding occurs in mouse familial combined hyperlipidemia; however, this has not been confirmed in humans. Congestive heart failure is a manifestation of many CVDs, which may be improved by attenuating oxidative stress through the suppression of Trx and decreased reactive oxygen species. Angiotensin II is associated with hypertension and other CVDs, and its receptor blockade results in decreased oxidative stress with reduced Trx levels. Inflammation is a major causative factor of CVDs, and myocarditis as an example, is associated with increased Trx levels. Vascular endothelial dysfunction has an association with CVD. This dysfunction is alleviated by hormone replacement therapy, which involves decreased oxidative stress and Trx levels. Diabetes mellitus has a major association with CVDs; increase in Trx levels may reflect insulin resistance. Identification of Trx system abnormalities may lead to innovative approaches to treat multiple CVDs and other pathologies.

Increased expression of anti-oxidant molecule Thioredoxin-1 on T cells improves immunotherapeutic control of tumors (VAC7P.1039)

Adoptive transfer of tumor epitope reactive T cells is a promising strategy to control tumor growth. However, chronically stimulated T cells expanded for adoptive cell transfer (ACT) are susceptible to cells death in an oxidative tumor microenvironment. Since oxidation of cell surface thiols (c-SH) also alters functionality of proteins, we hypothesized that increased level of thioredoxin, an anti-oxidant molecule that facilitates reduction of proteins by cysteine thiol-disulfide exchange, in T cells will result in sustained anti-tumor function. We thus crossed Trx1 transgenic mice with gp100 reactive TCR (Pmel) to generate Pmel/Trx mice. The Trx overexpressing transgenic T cells expressed higher thiols that inversely correlated with ROS, and susceptibility to TCR restimulation or H2O2 mediated cell death. These Trx1 expressing T cells showed CD62Lhi central memory-like (TCM) phenotype with reduced effector function (IFNglo2-NBDGlo), and were less effective in controlling tumor upon adoptive transfer. However, adoptive transfer of Pmel cells mixed with Pmel/Trx1 cells in 1:1 ratio markedly improved tumor control as compared to the mice that were transferred Pmel or Pmel/Trx T cells alone. It is likely that Pmel immediate effectors and Pmel/Trx cells with T-stem cell memory phenotype (i.e. CD62LhiCD44loCD122+Sca1hi), contributed to the improved tumor control. Thus, strategies to increase anti-oxidant capacity of anti-tumor T cells could have immunotherapeutic implications.

Cardiomyopathy and Worsened Ischemic Heart Failure in SM22-α Cre-Mediated Neuropilin-1 Null Mice: Dysregulation of PGC1α and Mitochondrial Homeostasis

OBJECTIVE

Neuropilin-1 (NRP-1) is a multidomain membrane receptor involved in angiogenesis and development of neuronal circuits, however, the role of NRP-1 in cardiovascular pathophysiology remains elusive.

APPROACH AND RESULTS

In this study, we first observed that deletion of NRP-1 induced peroxisome proliferator-activated receptor γ coactivator 1α in cardiomyocytes and vascular smooth muscle cells, which was accompanied by dysregulated cardiac mitochondrial accumulation and induction of cardiac hypertrophy- and stress-related markers. To investigate the role of NRP-1 in vivo, we generated mice lacking Nrp-1 in cardiomyocytes and vascular smooth muscle cells (SM22-α-Nrp-1 KO), which exhibited decreased survival rates, developed cardiomyopathy, and aggravated ischemia-induced heart failure. Mechanistically, we found that NRP-1 specifically controls peroxisome proliferator-activated receptor γ coactivator 1 α and peroxisome proliferator-activated receptor γ in cardiomyocytes through crosstalk with Notch1 and Smad2 signaling pathways, respectively. Moreover, SM22-α-Nrp-1 KO mice exhibited impaired physical activities and altered metabolite levels in serum, liver, and adipose tissues, as demonstrated by global metabolic profiling analysis.

CONCLUSIONS

Our findings provide new insights into the cardioprotective role of NRP-1 and its influence on global metabolism.

Targeted gene deletion of prolyl hydroxylase domain protein 3 triggers angiogenesis and preserves cardiac function by stabilizing hypoxia inducible factor 1 alpha following myocardial infarction

The key oxygen sensing molecules, Prolyl-hydroxylase domain 1-3 enzymes (PHD1-3), regulate hypoxia-inducible factor (HIF) under hypoxia. In the settings of cardiomyopathy and ischemia-reperfusion injury, PHD3 expression is elevated, resulting in decreased HIF activation. The role of PHD3 in myocardial injury is poorly understood. Hence, we aimed to determine the effects of PHD3 deletion in mice on HIF-1α and other related pathways following myocardial infarction (MI). Left coronary artery (LAD) in both wild type and prolyl hydroxylase 3 knock out (PHD3⁻/⁻) mice was ligated to induce myocardial infarction. Electrophoretic mobility shift analysis showed significant increase in DNA-binding activity of HIF-1α in PHD3⁻/⁻ mice as compared to wild type (WT) mice post MI. The PHD3⁻/⁻MI group also showed decreased fibrosis. Seven days after MI, enhanced capillary/arteriolar density was observed compared to WTMI group. PHD3⁻/⁻ mice subjected to MI also showed improved cardiac functions (Ejection fraction and Fractional shortening), as assessed by echocardiogram, compared to WT. Western blot analysis showed increased VEGF, Ang-1 & Bcl-2 expression in PHD3⁻/⁻MI group. In conclusion, ablation of the PHD3 gene resulted in increased angiogenesis and cardiac function after infarction thereby offering a potential target for pharmacological management of ischemic myocardial disease.

Deletion of prolyl hydroxylase domain proteins (PHD1, PHD3) stabilizes hypoxia inducible factor-1 alpha, promotes neovascularization, and improves perfusion in a murine model of hind-limb ischemia

BACKGROUND

There is an emerging focus on investigating innovative therapeutic molecules that can potentially augment neovascularization in order to treat peripheral arterial disease (PAD). Although prolyl hydroxylase domain proteins 1 and 3 (PHD1 and PHD3) may modulate angiogenesis via regulation of hypoxia inducible factor-1α (HIF-1α), there has been no study directly addressing their roles in ischemia-induced vascular growth. We hypothesize that PHD1(-/-) or PHD3(-/-) deficiency might promote angiogenesis in the murine hind-limb ischemia (HLI) model.

STUDY DESIGN

Wild type (WT), PHD1(-/-) and PHD3(-/-) male mice aged 8-12weeks underwent right femoral artery ligation. Post-procedurally, motor function assessment and laser Doppler imaging were periodically performed. The mice were euthanized after 28days and muscles were harvested. Immunohistochemical analysis was performed to determine the extent of angiogenesis by measuring capillary and arteriolar density. VEGF expression was quantified by enzyme-linked immunosorbent assay (ELISA). Bcl-2 and HIF-1α were analyzed by immunofluorescence. Fibrosis was measured by picrosirius red staining.

RESULTS

PHD1(-/-) and PHD3(-/-) mice showed significantly improved recovery of perfusion and motor function score when compared to WT after femoral artery ligation. These mice also exhibited increased capillary and arteriolar density, capillary/myocyte ratio along with decreased fibrosis compared to WT. VEGF, Bcl-2 and HIF-1α expression increased in PHD1(-/-) and PHD3(-/-) mice compared to WT.

CONCLUSIONS

Taken together these results suggest that PHD1 and PHD3 deletions promote angiogenesis in ischemia-injured tissue, and may present a promising therapeutic strategy in treating PAD.

Cardioprotective efficacy of a novel antioxidant mix VitaePro against ex vivo myocardial ischemia-reperfusion injury

Circumstantial evidence frequently implicates oxygen-derived free radicals and oxidative stress as mediators of myocardial ischemia/reperfusion (I/R) injury. Therefore, external supplementation of natural antioxidants plays a main role as cardioprotective compounds. This study was designed to evaluate the cardioprotective effect of VitaePro (70 mg/kg body weight, 21 days), a novel antioxidant mix of astaxanthin, lutein and zeaxanthin in a rat ex vivo model of ischemia/reperfusion injury. The cardioprotective effect of VitaePro was also compared with vitamin E (70 mg/kg body weight, 21 days) treatment. Rats were randomized into control I/R (CIR), VitaePro I/R (VPIR) and Vitamin E I/R (VEIR). After 21 days of oral treatment, isolated hearts from each group were subjected to 30 min of ischemia followed by 2 h of reperfusion. In the VPIR group compared to CIR and VEIR groups at 2 h of reperfusion, increased left ventricular functional recovery, such as left ventricular developed pressure (92.7 ± 0.7 vs. 85.3 ± 0.3 and 89.4 ± 1.2 mm Hg), dp/dt max (2518.7 ± 77.9 vs. 1962.5 ± 24 and 2255.7 ± 126.6 mm Hg/s), and aortic flow (21.5 ± 1.36 vs. 4.4 ± 0.6 and 13.2 ± 1.02 ml/min) were observed. The infarct size (27.68 ± 1.7 vs. 45.4 ± 1.8 and 35.4 ± 0.6%), apoptotic cardiomyocytes (61.7 ± 10.6 vs. 194.1 ± 14.8 and 118.7 ± 15.4 counts/100 HPF) and thiobarbituric acid reactive substances levels (80 ± 3 vs. 127 ± 5 and 103 ± 2 nM/mg tissue) also were decreased in VPIR group when compared to CIR and VEIR. As evidenced by the data, administration of vitamin E offered substantial cardioprotection to I/R injury, but VitaePro enhanced cardioprotection significantly more than vitamin E treatment. Taken in concert, the results of this study suggests that the oral ingestion of VitaePro protects myocardium from ischemia/reperfusion injury by decreasing oxidative stress and apoptosis, which may be of therapeutic benefit in the treatment of cardiovascular complications. However, further in vivo animal and human intervention studies are warranted before establishing any recommendations about usage of VitaePro for human cardiovascular complications.

Molecular mechanisms of action and therapeutic uses of pharmacological inhibitors of HIF-prolyl 4-hydroxylases for treatment of ischemic diseases

SIGNIFICANCE

In this review, we have discussed the efficacy and effect of small molecules that act as prolyl hydroxylase domain inhibitors (PHDIs). The use of these compounds causes upregulation of the pro-angiogenic factors and hypoxia inducible factor-1α and -2α (HIF-1α and HIF-2α) to enhance angiogenic, glycolytic, erythropoietic, and anti-apoptotic pathways in the treatment of various ischemic diseases responsible for significant morbidity and mortality in humans.

RECENT ADVANCES

Sprouting of new blood vessels from the existing vasculature and surgical intervention, such as coronary bypass and stent insertion, have been shown to be effective in attenuating ischemia. However, the initial reentry of oxygen leads to the formation of reactive oxygen species that cause oxidative stress and result in ischemia/reperfusion (IR) injury. This apparent "oxygen paradox" must be resolved to combat IR injury. During hypoxia, decreased activity of PHDs initiates the accumulation and activation of HIF-1α, wherein the modulation of both PHD and HIF-1α appears as promising therapeutic targets for the pharmacological treatment of ischemic diseases.

CRITICAL ISSUES

Research on PHDs and HIFs has shown that these molecules can serve as therapeutic targets for ischemic diseases by modulating glycolysis, erythropoiesis, apoptosis, and angiogenesis. Efforts are underway to identify and synthesize safer small-molecule inhibitors of PHDs that can be administered in vivo as therapy against ischemic diseases.

FUTURE DIRECTIONS

This review presents a comprehensive and current account of the existing small-molecule PHDIs and their use in the treatment of ischemic diseases with a focus on the molecular mechanisms of therapeutic action in animal models.

Conundrum of pathogenesis of diabetic cardiomyopathy: role of vascular endothelial dysfunction, reactive oxygen species, and mitochondria

Diabetic cardiomyopathy and heart failure have been recognized as the leading causes of mortality among diabetics. Diabetic cardiomyopathy has been characterized primarily by the manifestation of left ventricular dysfunction that is independent of coronary artery disease and hypertension among the patients affected by diabetes mellitus. A complex array of contributing factors including the hypertrophy of left ventricle, alterations of metabolism, microvascular pathology, insulin resistance, fibrosis, apoptotic cell death, and oxidative stress have been implicated in the pathogenesis of diabetic cardiomyopathy. Nevertheless, the exact mechanisms underlying the pathogenesis of diabetic cardiomyopathy are yet to be established. The critical involvement of multifarious factors including the vascular endothelial dysfunction, microangiopathy, reactive oxygen species (ROS), oxidative stress, mitochondrial dysfunction has been identified in the mechanism of pathogenesis of diabetic cardiomyopathy. Although it is difficult to establish how each factor contributes to disease, the involvement of ROS and mitochondrial dysfunction are emerging as front-runners in the mechanism of pathogenesis of diabetic cardiomyopathy. This review highlights the role of vascular endothelial dysfunction, ROS, oxidative stress, and mitochondriopathy in the pathogenesis of diabetic cardiomyopathy. Furthermore, the review emphasizes that the puzzle has to be solved to firmly establish the mitochondrial and/or ROS mechanism(s) by identifying their most critical molecular players involved at both spatial and temporal levels in diabetic cardiomyopathy as targets for specific and effective pharmacological/therapeutic interventions.

HIF-prolyl hydroxylases and cardiovascular diseases

Prolyl hydroxylases belong to the family of iron- and 2-oxoglutamate-dependent dioxygenase enzyme. Several distinct prolyl hydroxylases have been identified. The hypoxia-inducible factor (HIF) prolyl hydroxylase termed prolyl hydroxylase domain (PHD) enzymes play an important role in oxygen regulation in the physiological network. There are three isoforms that have been identified: PHD1, PHD2 and PHD3. Deletion of PHD enzymes result in stabilization of HIFs and offers potential treatment options for many ischemic disorders such as peripheral arterial occlusive disease, myocardial infarction, and stroke. All three isoforms are oxygen sensors that regulate the stability of HIFs. The degradation of HIF-1α is regulated by hydroxylation of the 402/504 proline residue by PHDs. Under hypoxic conditions, lack of oxygen causes hydroxylation to cease HIF-1α stabilization and subsequent translocation to the nucleus where it heterodimerizes with the constitutively expressed β subunit. Binding of the HIF-heterodimer to specific DNA sequences, named hypoxia-responsive elements, triggers the transactivation of target genes. PHD regulation of HIF-1α-mediated cardioprotection has resulted in considerable interest in these molecules as potential therapeutic targets in cardiovascular and ischemic diseases. In recent years, attention has been directed towards identifying small molecule inhibitors of PHD. It is postulated that such inhibition might lead to a clinically useful strategy for protecting the myocardium against ischemia and reperfusion injury. Recently, it has been reported that the orally absorbed PHD inhibitor GSK360A can modulate HIF-1α signaling and protect the failing heart following myocardial infarction. Furthermore, PHD1 deletion has been found to have beneficial effects through an increase in tolerance to hypoxia of skeletal muscle by reprogramming basal metabolism. In the mouse liver, such deletion has resulted in protection against ischemia and reperfusion. As a result of these preliminary findings, PHDs is attracting increasing interest as potential therapeutic targets in a wide range of diseases.

Nutrition and the healthy heart with an exercise boost

In this era of potent medications and major cardiovascular (CV) procedures, the value of nutrition can be forgotten. A healthy diet is essential, regardless of CV risk. Caloric balance is inherent to a good diet. Despite patients who say they eat little, ideal weight can be maintained if calories are burned. Composition is another component of a healthy diet. The Dietary Approaches to Stop Hypertension (DASH) and Mediterranean diets provide proof of CV benefit from their specific content. Metabolic syndrome (MS) is associated with poor diet and obesity. A healthy diet with good nutrition benefits the MS patient and associated conditions such as obesity and diabetes. Exercise, in conjunction with a healthy diet and good nutrition, helps maintain optimal weight and provides CV benefit such as decreased inflammation and increased vasodilatation. Whether vitamins or other nutritional supplements are important in a healthy diet is unproven. Nevertheless, the most promising data of added benefit to a healthy diet is with vitamin D. Some dietary supplements also have promise. Alcohol, in moderation, especially red wine, has nutritional and heart protective benefits. Antioxidants, endogenous or exogenous, have received increased interest and appear to play a favorable nutritional role. CV health starts with good nutrition.

Factors influencing epigenetic mechanisms and related diseases

It is becoming clear that epigenetic mechanisms are associated with disease. To date, a myriad of epigenetic alterations, including altered DNA methylation and aberrant histone post-translational modifications, have been linked with various conditions. The most widely investigated example is the link between aberrant DNA methylation and malignancy that has lead to the clinical use of the DNA methyltransferase inhibitors, azacitidine and decitabine, for the treatment of myelodysplastic syndromes. Similarly, defective histone acetylation status has been associated with malignancy, providing the basis for the clinical use of the histone deacetylase inhibitors suberoylanilide hydroxamic acid and depsipeptide for the treatment of cutaneous T-cell lymphoma. In addition, there is an emerging association between perturbed fetal epigenetic programming and developmental origins of disease due to both nutritional and environmental factors. In particular, epigenetic events associated with metabolic syndrome have been identified. Related epigenetic mechanisms as well potential pharmacological and dietary interventions at critical periods of development form a large part of the discussion in this Forum. Further, this Forum provides an in-depth account of the association between epigenetic mechanisms and carcinogenesis with a focus on disease prevention with dietary chromatin-modifying compounds. Finally, the association between aberrant epigenetic events and neurodegenerative conditions, such as Alzheimer's disease (AD), is becoming apparent. A research article in this Forum identifies a potential new polymorphism associated with one-carbon metabolism that may contribute to the pathogenesis of AD. Overall, this Forum provides a detailed account of known epigenetic processes in developmental programming and human disease.

Epigenetic manifestation of metabolic syndrome and dietary management

SIGNIFICANCE

Metabolic syndrome constitutes a group of disorders such as insulin resistance, hypertension, and hypertriglyceridemia, predisposing an individual to risk factors such as cardiovascular disease, diabetes, obesity, and dyslipidemia. A majority of these diseases are influenced by the environmental factors, nutrient uptake, and genetic profile of an individual that together dysregulate gene function. These genetic and nongenetic factors are reported to introduce epigenetic cues that modulate the gene function which is inherited by the offspring.

RECENT ADVANCES

Considering the epigenetic modulation of the metabolic disorders, nutrigenomics has been distinctly categorized as a branch that deals with modulatory effect of nutrients on metabolic disorders and disease progression by supplementing the individuals with key nutrient-enriched diets which are derived from plant and animal sources.

CRITICAL ISSUES

Nutritional components of the diet regulate the metabolic health of an individual either by controlling the expression of some key genes related to metabolic pathways or by modulating the epigenetic events on such genes. The present article discusses various metabolic disorders in detail and the effect of nutrients on the specific genes causing those disorders. We also highlight the molecular mechanisms of some metabolic disorders through epigenetic modifications and possible therapeutic interventions.

FUTURE DIRECTIONS

With the advent of high-throughput technologies and epigenetic modulation of the metabolic disorders, an altered epigenetic code that is programmed due to improper nutrients can be reverted back by supplementing the diet with various plant-derived compounds. The implication of small molecular drugs is also of utmost significance for challenging the metabolic disorders.

Glutaredoxin-1 overexpression enhances neovascularization and diminishes ventricular remodeling in chronic myocardial infarction

Oxidative stress plays a critical role in the pathophysiology of cardiac failure, including the modulation of neovascularization following myocardial infarction (MI). Redox molecules thioredoxin (Trx) and glutaredoxin (Grx) superfamilies actively maintain intracellular thiol-redox homeostasis by scavenging reactive oxygen species. Among these two superfamilies, the pro-angiogenic function of Trx-1 has been reported in chronic MI model whereas similar role of Grx-1 remains uncertain. The present study attempts to establish the role of Grx-1 in neovascularization and ventricular remodeling following MI. Wild-type (WT) and Grx-1 transgenic (Grx-1(Tg/+)) mice were randomized into wild-type sham (WTS), Grx-1(Tg/+) Sham (Grx-1(Tg/+)S), WTMI, Grx-1(Tg/+)MI. MI was induced by permanent occlusion of the LAD coronary artery. Sham groups underwent identical time-matched surgical procedures without LAD ligation. Significant increase in arteriolar density was observed 7 days (d) after surgical intervention in the Grx-1(Tg/+)MI group as compared to the WTMI animals. Further, improvement in myocardial functional parameters 30 d after MI was observed including decreased LVIDs, LVIDd, increased ejection fraction and, fractional shortening was also observed in the Grx-1(Tg/+)MI group as compared to the WTMI animals. Moreover, attenuation of oxidative stress and apoptotic cardiomyocytes was observed in the Grx-1(Tg/+)MI group as compared to the WTMI animals. Increased expression of p-Akt, VEGF, Ang-1, Bcl-2, survivin and DNA binding activity of NF-κB were observed in the Grx-1(Tg/+)MI group when compared to WTMI animals as revealed by Western blot analysis and Gel-shift analysis, respectively. These results are the first to demonstrate that Grx-1 induces angiogenesis and diminishes ventricular remodeling apparently through neovascularization mediated by Akt, VEGF, Ang-1 and NF-κB as well as Bcl-2 and survivin-mediated anti-apoptotic pathway in the infarcted myocardium.

Diabetes, oxidative stress, molecular mechanism, and cardiovascular disease--an overview

In recent years, diabetes and its associated complications have come to represent a major public health concern. It is a complex disease characterized by multiple metabolic derangements and is known to impair cardiac function by disrupting the balance between pro-oxidants and antioxidants at the cellular level. The subsequent generation of reactive oxygen species (ROS) and accompanying oxidative stress are hallmarks of the molecular mechanisms responsible for cardiovascular disease. Among several oxidative stress-mediated mechanisms that have been proposed, ROS-mediated oxidative stress has received the most attention. ROS have been shown to interact with proteins, lipids, and DNA, causing damage to the cellular macromolecules and subsequently, deterioration of cellular function. Induction of thioredoxin-1 (Trx1) gene expression has been demonstrated to protect the diabetic myocardium from dysfunction by reducing oxidative stress and enhancing the expression of heme oxygenase-1 (HO-1) and vascular endothelial growth factor (VEGF). The failure of antioxidants to consistently demonstrate clinical benefit necessitates further investigation of the role of oxidative stress in diabetes-mediated cardiovascular disease.

Curcumin heals indomethacin-induced gastric ulceration by stimulation of angiogenesis and restitution of collagen fibers via VEGF and MMP-2 mediated signaling

AIM

We examined the molecular mechanism of curcumin in a preventive and therapeutic model of indomethacin-induced gastric ulceration with regard to angiogenic processes.

RESULTS

Disrupted blood vessels, reduced collagen matrices, and significant (60%) injury to mucosal cells were observed during ulceration. In addition, ulcerated tissues exhibited decreased matrix metalloproteinase (MMP)-2 and vascular endothelial growth factor (VEGF) expression in blood vessels. Interestingly, curcumin blocked ulceration by induction of collagenization and angiogenesis in gastric tissues via upregulation of MMP-2, membrane type (MT) 1-MMP, VEGF, and transforming growth factor (TGF)-β at protein and messenger ribonucleic acid (mRNA) levels. To examine the angiogenic properties of curcumin, we employed a chorioallantoic membrane model and Matrigel assay. During healing, curcumin promoted collagenization and angiogenesis as well as enhanced MMP-2 activity via positive MT1-MMP regulation and negative tissue inhibitor of metalloproteinase-2 regulation.

INNOVATION

Our study demonstrates that curcumin-mediated healing is associated with increased MMP-2, TGF-β, and VEGF expression and that it plays a pivotal role as an angiogenic modulator by stimulating vascular sprout formation and collagen fiber restoration in ulcerated tissues.

CONCLUSION

We conclude that curcumin remodels gastric tissues by restoring the collagen architecture and accelerating angiogenesis.