Intravenous Arginine Administration Promotes Proangiogenic Cells Mobilization and Attenuates Lung Injury in Mice with Polymicrobial Sepsis

Exosomes derived from endothelial progenitor cells ameliorate LPS-induced brain microvascular endothelial cells injury by delivering miR-126a-5p

Endothelial progenitor cells (EPCs) play a crucial role in maintaining vascular health and aiding in the repair of damaged blood vessels. However, the specific impact of EPCs-derived exosomes on vascular endothelial cell injury caused by lipopolysaccharide (LPS) remains inadequately understood. This study aims to explore the potential benefits of EPC-exosomes in mitigating LPS-induced vascular injury and to elucidate the underlying mechanism. Initially, EPCs were isolated from mouse peripheral blood, and their identity was confirmed through flow cytometry and immunocytochemistry. Subsequently, the exosomes derived from EPCs were identified using transmission electron microscopy (TEM) and western blot analysis. A sepsis model was induced by subjecting brain microvascular endothelial cells (BMECs) to LPS-induced injury. Both EPC and their exosomes demonstrated a significant increase in BMECs proliferation, reduced apoptosis, decreased levels of pro-inflammatory factors (TNF-α, IL-6, and caspase-3), and enhanced sprouting and angiogenesis of BMECs. Notable, the Exosomes demonstrated a more pronounced impact on these parameters. Furthermore, both EPCs and Exosomes exhibited significantly increased levels of miR-126a-5p, with the Exosomes showing a more substantial enhancement. These findings suggest that supplementing exosomal miR-126a-5p from EPCs can provide protective effects on BMECs, offering a potential therapeutic option for treating sepsis-induced microvascular endothelial cell injury.

Exploring the mechanism of lung injury induced by lunar dust simulant in rats based on metabolomic analysis

Inflammatory response and oxidative stress are considered to be important mechanisms of lung injury induced by lunar dust. However, the pulmonary toxicological mechanism remains unclear. In the present study, Wistar rats were exposed to CLDS-i 7 days/week, 4 h/day, for 4 weeks in the mouth and nose. Lung tissue samples were collected for histopathological analysis and ultra-performance liquid chromatography-mass spectrometry analysis. Enzyme activities and expression levels of key metabolic enzymes were detected by biochemical analysis and real-time PCR. The pathological features of lung tissue showed that CLDS-i caused congestion and inflammation in the lungs, and the lung structure was severely damaged. Metabolomics analysis showed that 141 metabolites were significantly changed in the lung tissue of the CLDS-i group compared with the control group. Combined with Kegg pathway analysis, it was found that the changes of amino acid metabolites were involved in these pathways, indicating that the simulated lunar dust exposure had the most obvious effect on amino acid metabolism in the lung tissue of rats. Real-time PCR analysis showed that the mRNA expression of six key enzymes related to amino acid metabolism was changed, and the enzyme activities of these key enzymes were also changed, which were consistent with the results of qPCR. These results suggest that changes in amino acid metabolism may be closely related to the pathogenesis of lung injury induced by lunar dust, and amino acid metabolism may be a potential biomarker of lung diseases related to lunar dust exposure.

Multi-Omics Endotypes in ICU Sepsis-Induced Immunosuppression

It is evident that the admission of some patients with sepsis and septic shock to hospitals is occurring late in their illness, which has contributed to the increase in poor outcomes and high fatalities worldwide across age groups. The current diagnostic and monitoring procedure relies on an inaccurate and often delayed identification by the clinician, who then decides the treatment upon interaction with the patient. Initiation of sepsis is accompanied by immune system paralysis following "cytokine storm". The unique immunological response of each patient is important to define in terms of subtyping for therapy. The immune system becomes activated in sepsis to produce interleukins, and endothelial cells express higher levels of adhesion molecules. The proportions of circulating immune cells change, reducing regulatory cells and increasing memory cells and killer cells, having long-term effects on the phenotype of CD8 T cells, HLA-DR, and dysregulation of microRNA. The current narrative review seeks to highlight the potential application of multi-omics data integration and immunological profiling at the single-cell level to define endotypes in sepsis and septic shock. The review will consider the parallels and immunoregulatory axis between cancer and immunosuppression, sepsis-induced cardiomyopathy, and endothelial damage. Second, the added value of transcriptomic-driven endotypes will be assessed through inferring regulatory interactions in recent clinical trials and studies reporting gene modular features that inform continuous metrics measuring clinical response in ICU, which can support the use of immunomodulating agents.

Endothelial cell metabolism in sepsis

BACKGROUND

Endothelial dysfunction in sepsis is a pathophysiological feature of septic organ failure. Endothelial cells (ECs) exhibit specific metabolic traits and release metabolites to adapt to the septic state in the blood to maintain vascular homeostasis.

METHODS

Web of Science and PubMed were searched from inception to October 1, 2022. The search was limited to the English language only. Two reviewers independently identified studies related to EC metabolism in sepsis. The exclusion criteria were duplicate articles according to multiple search criteria.

RESULTS

Sixty articles were included, and most of them were cell and animal studies. These studies reported the role of glycolysis, oxidative phosphorylation, fatty acid metabolism, and amino acid metabolism in EC homeostasis. including glycolysis, oxidative phosphorylation, fatty acid metabolism and amino acid metabolism. However, dysregulation of EC metabolism can contribute to sepsis progression.

CONCLUSION

There are few clinical studies on EC metabolism in sepsis. Related research mainly focuses on basic research, but some scientific problems have also been clarified. Therefore, this review may provide an overall comprehension and novel aspects of EC metabolism in sepsis.

A new perspective on NO pathway in sepsis and ADMA lowering as a potential therapeutic approach

The nitric oxide pathway plays a critical role in vascular homeostasis. Increased levels of systemic nitric oxide (NO) are observed in preclinical models of sepsis and endotoxemia. This has led to the postulation that vasodilation by inducible nitric oxide synthase (iNOS) generated NO may be a mechanism of hypotension in sepsis. However, contrary to the expected pharmacological action of a nitric oxide synthase (NOS) inhibitor, clinical studies with L-NAME produced adverse cardiac and pulmonary events, and higher mortality in sepsis patients. Thus, the potential adverse effects of NO in human sepsis and shock have not been fully established. In recent years, the emerging new understanding of the NO pathway has shown that an endogenously produced inhibitor of NOS, asymmetric dimethylarginine (ADMA), a host response to infection, may play an important role in the pathophysiology of sepsis as well as organ damage during ischemia–reperfusion. ADMA induces microvascular dysfunction, proinflammatory and prothrombotic state in endothelium, release of inflammatory cytokines, oxidative stress and mitochondrial dysfunction. High levels of ADMA exist in sepsis patients, which may produce adverse effects like those observed with L-NAME. Several studies have demonstrated the association of plasma ADMA levels with mortality in sepsis patients. Preclinical studies in sepsis and ischemia–reperfusion animal models have shown that lowering of ADMA reduced organ damage and improved survival. The clinical finding with L-NAME and the preclinical research on ADMA “bed to bench” suggest that ADMA lowering could be a potential therapeutic approach to attenuate progressive organ damage and mortality in sepsis. Testing of this approach is now feasible by using the pharmacological molecules that specifically lower ADMA.

Intravenous Arginine Administration Attenuates the Inflammatory Response and Improves Metabolic Profiles in Diet-Induced Obese Mice after Sleeve Gastrectomy

Sleeve gastrectomy (SG) is a bariatric surgery that can effectively reduce weight and improve obesity-associated comorbidities. However, surgical stress intensifies inflammation and imbalanced metabolic profiles. Arginine (Arg) is a nutrient with immunomodulatory and anti-inflammatory properties. This study evaluated the short-term effects of Arg administration on adipocyte inflammation and metabolic alterations in obese mice after SG. Mice were assigned to normal and high-fat diet (HFD) groups. After 16 weeks, the HFD group were divided to sham (SH), SG with saline (SS), or Arg (SA) groups. SS and SA groups were postoperatively injected with saline or Arg via the tail vein and sacrificed at day 1 or 3 after the SG, respectively. Results showed that obesity caused elevated plasma glucose and leptin levels. The SG operation enhanced the expression of inflammatory cytokines and macrophage infiltration in adipose tissues, whereas hepatocyte gene expressions associated with lipid β-oxidation were downregulated. Arg treatment reversed the expressions of β-oxidation-associated genes and reduced lipid peroxide production in the liver. Additionally, adipose tissue expressions of inflammatory chemokines were reduced, while the M2 macrophage marker increased after surgery. The findings suggest that postoperative Arg administration elicited more balanced hepatic lipid metabolism, polarized macrophages toward the anti-inflammatory type, and attenuated adipocyte inflammation shortly after SG.

The effect of exosomes derived from unrestricted somatic stem cells on murine model of sepsis

Sepsis is a systemic infection mainly caused by bacterial infections. Despite all efforts and advances in treatment of sepsis, it's still considered as one of the leading causes of death in the hospitalized patients. Today we have to use novel therapies and one of the most important is cell free therapy. Exosomes have been introduced to have all cell contents without compatible tissue complex proteins which is a good candidate for transplantation. Unrestricted somatic stem cells (USSC) also known as mesenchymal stem cell progenitors due to their high proliferative capacity and low immune response, which is a novel therapy for sepsis. In this study, the effect of USSC-derived exosomes on sepsis was investigated using a mouse model. USSCs were isolated from human cord blood and characterized by flow cytometry and multilineage differentiation. The exosomes were then harvested from USSCs and characterized by transmission electron microscopy, Western blotting, and dynamic light scattering. The harvested exosomes were injected into the mouse model of sepsis. Biochemical, histological, molecular, and survival studies were performed in different groups. Our observation showed that USSC-derived exosomes can reduce inflammation in septic mice. Histopathological and biochemical findings in the sham group obviously showed multiorgan involvement, but these changes disappeared after seven days of exosome administration. Moreover, the expression of IRAK-1 and TRAF-6 (main adapter molecules in signaling pathways of inflammation) was decreased through negative regulation by miR-146a after 72 h of exosome administration; finally, it leads to a 2-fold increase in the level of IL-10 and a 2-fold decrease in the levels of IL-6 and TNF-α . In conclusion, we reported that direct injection of USSC- derived exosomes can be one of the important methods for the treatment of various aspects of sepsis due to their immunomodulatory properties.

The role of miR-199b-3p in regulating Nrf2 pathway by dihydromyricetin to alleviate septic acute kidney injury

The pathophysiology of septic acute kidney injury (AKI) is very complex and the fatality is high. Nrf2 is crucial for septic AKI, and dihydromyricetin (DMY) has a protective effect on LPS-induced AKI. We aimed to explore whether DMY could affect Nrf2 pathway by regulating miR-199b-3p and played a protective role in septic AKI. The mouse model was induced by cecal ligation and puncture (CLP) and the cell model was stimulated by LPS. Enzyme-linked immunosorbent assay was conducted to examine MDA, SOD, LDH, GSH, TNF-α, kidney injury molecule 1 (KIM-1), and IL-6 levels. The pathological changes were observed by hematoxylin-eosin staining. The targeted relationship between miR-199b-3p and Nrf2 was verified by a dual-luciferase reporter assay. Levels of SOD, GSH, NQO-1, Nrf2, and HO-1 were decreased, MDA, LDH, TNF-α, IL-6, and KIM-1, and miR-199b-3p were increased in the CLP group and LPS-induced HK-2 cells, while the effect was reversed after DMY treatment. There existed renal tubule cell edema and necrosis, inflammatory cell infiltration in the CLP group, the situation was partially improved by DMY. MiR-199b-3p bound to Nrf2. Nrf2 levels were increased, TNF-α, IL-6, and KIM-1 were decreased after transfected with miR-199b-3p inhibitor, these effects were reversed when co-transfected with si-Nrf2. TNF-α, IL-6, KIM-1, and miR-199b-3p levels were increased; Nrf2, NQO-1, and HO-1 levels were decreased in the LPS + DMY + mimics-miR group. MiR-199b-3p was increased in septic AKI models, DMY might alleviate septic AKI by regulating miR-199b-3p to affect the Nrf2 pathway.

Factors Affecting the Re-Endothelialization of Endothelial Progenitor Cell

The vascular endothelium, which plays an essential role in maintaining the normal shape and function of blood vessels, is a natural barrier between the circulating blood and the vascular wall tissue. The endothelial damage can cause vascular lesions, such as atherosclerosis and restenosis. After the vascular intima injury, the body starts the endothelial repair (re-endothelialization) to inhibit the neointimal hyperplasia. Endothelial progenitor cell is the precursor of endothelial cells and plays an important role in the vascular re-endothelialization. However, re-endothelialization is inevitably affected in vivo and in vitro by factors, which can be divided into two types, namely, promotion and inhibition, and act on different links of the vascular re-endothelialization. This article reviews these factors and related mechanisms.

Machine learning applied to serum and cerebrospinal fluid metabolomes revealed altered arginine metabolism in neonatal sepsis with meningoencephalitis

Background

Neonatal sepsis with meningoencephalitis is a common complication of sepsis, which is a leading cause of neonatal death and neurological dysfunction. Early identification of neonatal sepsis with meningoencephalitis is particularly important for reducing brain damage. We recruited 70 patients with neonatal sepsis, 42 of which were diagnosed as meningoencephalitis, and collected cerebrospinal fluid (CSF) and serum samples. The purpose of this study was to find neonatal sepsis with meningoencephalitis-related markers using unbiased metabolomics technology and artificial intelligence analysis based on machine learning methods.

Results

We found that the characteristics of neonatal sepsis with meningoencephalitis were manifested mainly as significant decreases in the concentrations of homo-l-arginine, creatinine, and other arginine metabolites in serum and CSF, suggesting possible changes in nitric oxide synthesis. The antioxidants taurine and proline in the serum of the neonatal sepsis with meningoencephalitis increased significantly, suggesting abnormal oxidative stress. Potentially harmful bile salts and aromatic compounds were significantly increased in the serum of the group with meningoencephalitis. We compared different machine learning methods and found that the lasso algorithm performed best. Combining the lasso and XGBoost algorithms was successful in predicting the concentration of homo-l-arginine in CSF per the concentrations of metabolite markers in the serum.

Conclusions

On the basis of machine learning combined with analysis of the serum and CSF metabolomes, we found metabolite markers related to neonatal sepsis with meningoencephalitis. The characteristics of neonatal sepsis with meningoencephalitis were manifested mainly by changes in arginine metabolism and related changes in creatinine metabolism.

Experimental Study on the Effect of Allogeneic Endothelial Progenitor Cells on Wound Healing in Diabetic Mice

Endothelial progenitor cells (EPCs) are involved in the neovascularization in traumatic and ischemic sites, but EPCs are "detained" in bone marrow under diabetic conditions, which results in reduction of the number of EPCs and their biological activity in peripheral blood. Based on our previous study to mobilize autologous bone marrow EPCs by administering AMD3100+G-CSF to realize the optimal effect, our present study is aimed at exploring the effects of transplanting EPCs locally in a wound model of diabetic mice. First, we prepared and identified EPCs, and the biological functions and molecular characteristics were compared between EPCs from DB/+ and DB/DB mice. Then, we performed full-thickness skin resection in DB/DB mice and tested the effect of local transplantation of EPCs on skin wound healing. The wound healing process was recorded using digital photographs. The animals were sacrificed on postoperative days 7, 14, and 17 for histological and molecular analysis. Our results showed that DB/+ EPCs were biologically more active than those of DB/DB EPCs. When compared with the control group, local transplantation of EPCs accelerated wound healing in DB/DB mice by promoting wound granulation tissue formation, angiogenesis, and collagen fiber deposition, but there was no significant difference in wound healing between DB/+ EPCs and DB/DB EPCs transplanted into the wound. Furthermore, local transplantation of EPCs promoted the expression of SDF-1, CXCR4, and VEGF. We speculated that EPC transplantation may promote wound healing through the SDF-1/CXCR4 axis. This point is worth exploring further. Present data are of considerable significance because they raise the possibility of promoting wound healing by isolating autologous EPCs from the patient, which provides a new approach for the clinical treatment of diabetic wounds in the future.

Molecular mechanisms by which iNOS uncoupling can induce cardiovascular dysfunction during sepsis: Role of posttranslational modifications (PTMs)

Human sepsis is the result of a multifaceted pathological process causing marked dysregulation of cardiovascular responses. A more sophisticated understanding of the pathogenesis of sepsis is certainly prerequisite. Evidence from studies provide further insight into the role of inducible nitric oxide synthase (iNOS) isoform. Results on inhibition of iNOS in sepsis models remain inconclusive. Concern has been devoted to improving our knowledge and understanding of the role of iNOS. The aim of this review is to define the role of iNOS in redox homeostasis disturbance, the detailed mechanisms linking iNOS and posttranslational modifications (PTMs) to cardiovascular dysfunctions, and their future implications in sepsis settings. Many questions related to the iNOS and PTMs still remain open, and much more work is needed on this.

Intravenous Arginine Administration Downregulates NLRP3 Inflammasome Activity and Attenuates Acute Kidney Injury in Mice with Polymicrobial Sepsis

Acute kidney injury (AKI) is a major complication of sepsis. Nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasomes are multiprotein complexes that mediate septic AKI. L-arginine (Arg) is a conditionally essential amino acid in catabolic conditions and a substrate for nitric oxide (NO) production; however, its use in sepsis is controversial. This study investigated the effect of intravenous Arg supplementation on modulating NLRP3 inflammasome activity in relation to septic AKI. Mice were divided into normal control (NC), sham, sepsis saline (SS), and sepsis Arg (SA) groups. In order to investigate the role of NO, L-N6-(1-iminoethyl)-lysine hydrochloride (L-NIL), an inducible NO synthase inhibitor, was administered to the sepsis groups. Sepsis was induced using cecal ligation and puncture (CLP). The SS and SA groups received saline or Arg via tail vein 1 h after CLP. Mice were sacrificed at 6, 12, and 24 h after sepsis. The results showed that compared to the NC group, septic mice had higher plasma kidney function parameters and lower Arg levels. Also, renal NLRP3 inflammasome protein expression and tubular injury score increased. After Arg treatment, plasma Arg and NO levels increased, kidney function improved, and expressions of renal NLRP3 inflammasome-related proteins were downregulated. Changes in plasma NO and renal NLRP3 inflammasome-related protein expression were abrogated when L-NIL was given to the Arg sepsis groups. Arg plus L-NIL administration also attenuated kidney injury after CLP. The findings suggest that intravenous Arg supplementation immediately after sepsis restores plasma Arg levels and is beneficial for attenuating septic AKI, partly via NO-mediated NLRP3 inflammasome inhibition.

Intravenous Arginine Administration Benefits CD4+ T-Cell Homeostasis and Attenuates Liver Inflammation in Mice with Polymicrobial Sepsis

This study investigated the effects of a single dose of arginine (Arg) administration at the beginning of sepsis on CD4+ T-cell regulation and liver inflammation in C57BL/6J mice. Mice were divided into normal control (NC), sham (SH), sepsis saline (SS), and sepsis Arg (SA) groups. An inducible nitric oxide (NO) synthase (iNOS) inhibitor was administered to additional sepsis groups to evaluate the role of NO during sepsis. Sepsis was induced using cecal ligation and puncture (CLP). The SS and SA groups received saline or Arg (300 mg/kg body weight) via tail vein 1 h after CLP. Mice were euthanized at 12 and 24 h post-CLP. Blood, para-aortic lymph nodes, and liver tissues were collected for further measurement. The findings showed that sepsis resulted in decreases in blood and para-aortic lymph node CD4+ T-cell percentages, whereas percentages of interleukin (IL)-4- and IL-17-expressing CD4+ T cells were upregulated. Compared to the SS group, Arg administration resulted in maintained circulating and para-aortic lymph node CD4+ T cells, an increased Th1/Th2 ratio, and a reduced Th17/Treg ratio post-CLP. In addition, levels of plasma liver injury markers and expression of inflammatory genes in liver decreased. These results suggest that a single dose of Arg administered after CLP increased Arg availability, sustained CD4+ T-cell populations, elicited more-balanced Th1/Th2/Th17/Treg polarization in the circulation and the para-aortic lymph nodes, and attenuated liver inflammation in sepsis. The favorable effects of Arg were abrogated when an iNOS inhibitor was administered, which indicated that NO may be participated in regulating the homeostasis of Th/Treg cells and subsequent liver inflammation during sepsis.

Glycine Attenuates Lipopolysaccharide-Induced Acute Lung Injury by Regulating NLRP3 Inflammasome and NRF2 Signaling

Glycine supplementation has been reported to alleviate lipopolysaccharide (LPS)-induced lung injury in mice. However, the underlying mechanisms responsible for this beneficial effect remain unknown. In the present study, male C57BL/6 mice were treated with aerosolized glycine (1000 mg in 5 mL of 0.9% saline) or vehicle (0.9% saline) once daily for 7 continuous days, and then were exposed to aerosolized LPS (5 mg in 5 mL of 0.9% saline) for 30 min to induce lung injury. Sera and lung tissues were collected 24 h post LPS challenge. Results showed that glycine pretreatment attenuated LPS-induced decreases of mucin at both protein and mRNA levels, reduced LPS-triggered upregulation of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interferons, granulocyte-macrophage colony-stimulating factor (GM-CSF), and interleukins. Further study showed that glycine-reduced LPS challenge resulted in the upregulation of nuclear factor κB (NF-κB), nucleotide binding domain (NOD)-like receptor protein 3 (NLRP3) inflammasome. In addition, LPS exposure led to the downregulation of NRF2 and downstream targets, which were significantly improved by glycine administration in the lung tissues. Our findings indicated that glycine pretreatment prevented LPS-induced lung injury by regulating both NLRP3 inflammasome and NRF2 signaling.

Protective Effects of Functional Amino Acids on Apoptosis, Inflammatory Response, and Pulmonary Fibrosis in Lipopolysaccharide-Challenged Mice

Lung injury is a complicated and lethal condition characterized by alveolar barrier disruption, pulmonary edema, enhanced inflammation, and apoptosis in alveoli. However, therapeutic strategies to ameliorate lung injury without exerting side effects are not available. Functional amino acids have been shown to have anti-inflammatory and anti-apoptotic effects under various conditions. The objective of this study was to test the hypothesis that arginine, glutamine, or glycine supplementation ameliorated lipopolysaccharide (LPS)-induced lung injury in mice. Mice pretreated with aerosolized arginine, glutamine, or glycine were exposed to aerosolized LPS to induce lung injury. Results showed that arginine or glycine pretreatment beneficially reduced LPS-induced collagen deposition, apoptosis of alveolar cells, expression of inflammatory cytokines and chemokines, and accumulation of neutrophils and macrophages in lung tissues of mice, thus contributing to improved alveolar integrity and function. Glutamine administration reduced LPS-induced collagen deposition and inflammatory cytokines without affecting any other parameters examined in the study. Our findings indicated that arginine or glycine pretreatment effectively alleviated LPS-induced lung injury by inhibiting the accumulation of lymphocytes, the release of inflammatory cytokines and chemokines, and the apoptosis of alveolar cells. Supplementation of arginine or glycine may be a novel nutritional strategy to reduce deleterious effects of bacterial infection on alveolar function.

Velvet Antler Mobilizes Endothelial Progenitor Cells to Promote Angiogenesis and Repair Vascular Endothelial Injury in Rats Following Myocardial Infarction

Objective: This investigation examined the effect of velvet antler (VA) on endothelial progenitor cells (EPCs) and the associated effects to promote angiogenesis and repair vascular endothelial injury in rats with myocardial infarction (MI). Methods: VA was analyzed by liquid chromatography-mass spectrometry. Male Sprague Dawley rats were randomly divided into four groups: sham, MI, VA, and VA + DAPT (gamma-secretase inhibitor IX, a specific blocker of the Notch signaling pathway) group. The rats underwent ligation of the left anterior descending coronary artery for the establishment of MI. Sham-operated rats were used as controls. Blood was taken from the orbital plexus on the first and third days after the operation, and all rats were euthanized on the 7th day after surgery. The blood samples were used to detect the contents of circulating endothelial progenitor cells (CEPCs) and vascular endothelial growth factor (VEGF). Echocardiography was used to test the cardiac function. Cardiac tissue was used for immunohistochemistry and electron microscope, and the marginal zone of the MI tissue was used for western blot and reverse transcription-quantitative polymerase chain reaction. Results: The number of basically qualitative metabolites is 445. Among them, there are 74 substances with relative content greater than 0.05%. VA increased the concentration of CEPCs and VEGF in serum, CD133 content and microvessel density (MVD), and protected the morphology of microvascular endothelial cells in the marginal area of MI at 7 days post-MI surgery. CEPCs and MVD in the VA +DAPT group were lower than those of VA group. VA increased the protein expressions of Jagged-1, Notch1, NICD and HES1, and the mRNA expressions of Hes1 and Hey2, while some of the effects could be suppressed by DAPT. Conclusion: These results suggest that VA promotes the mobilization of EPCs to promote angiogenesis and repair vascular endothelial cell damage in post-MI rats, and these effects may be due to activation of the Notch signal pathway.

Arginine administration increases circulating endothelial progenitor cells and attenuates tissue injury in a mouse model of hind limb ischemia/reperfusion

OBJECTIVE

This study investigated whether the administration of L-Arginine, the precursor of nitric oxide, increases the percentages of blood endothelial progenitor cells and protects against ischemia/reperfusion induced inflammatory response in a mouse model of hind-limb IR injury.

METHOD

C57BL/6 mice were randomized to one normal-control and four ischemia/reperfusion groups. The normal-control group did not undergo an ischemia/reperfusion procedure but mice in the ischemia/reperfusion groups were subjected to 150 min of unilateral hind-limb ischemia. The ischemia/reperfusion groups were subjected to either intravenous saline or L-Arginine (300 mg/kg body weight) administration before reperfusion and then sacrificed at either 24 h or 48 h after reperfusion. Blood and muscle tissues were collected for analysis.

RESULTS

Ischemia/reperfusion injury led to a significant decrease in the percentage of blood endothelial progenitor cells and plasma nitric oxide concentration but plasma interleukin-6 levels and gene expression of inflammatory cytokines in injured muscle tissue were elevated. In contrast to the saline groups, those with L-Arginine administration were able to maintain a normal level of blood endothelial progenitor cells. In addition, after reperfusion, concentrations of nitric oxide, matrix metallopeptidase-9, and vascular endothelial growth factor in plasma were upregulated but keratinocyte-derived chemokine and monocyte chemoattractant protein-1 messenger RNA expressions in muscle were attenuated 48 h after reperfusion. Histologic findings also demonstrated a significant reduction of ischemia/reperfusion-induced muscle injury when L-Arginine was administered.

CONCLUSION

A single dose of L-Arginine administration before reperfusion increases the percentage of endothelial progenitor cells and reduces the inflammatory reaction locally and systemically after ischemia/reperfusion injury.

Nutrients, Infectious and Inflammatory Diseases

A balanced diet with sufficient essential nutritional elements is critical for maintaining a healthy body.[...].