Protective effect of melatonin-supported adipose-derived mesenchymal stem cells against small bowel ischemia-reperfusion injury in rat

Advancements in Antioxidant-Based Therapeutics for Spinal Cord Injury: A Critical Review of Strategies and Combination Approaches

Spinal cord injury (SCI) initiates a cascade of secondary damage driven by oxidative stress, characterized by the excessive production of reactive oxygen species and other reactive molecules, which exacerbate cellular and tissue damage through the activation of deleterious signaling pathways. This review provides a comprehensive and critical evaluation of recent advancements in antioxidant-based therapeutic strategies for SCI, including natural compounds, RNA-based therapies, stem cell interventions, and biomaterial applications. It emphasizes the limitations of single-regimen approaches, particularly their limited efficacy and suboptimal delivery to injured spinal cord tissue, while highlighting the synergistic potential of combination therapies that integrate multiple modalities to address the multifaceted pathophysiology of SCI. By analyzing emerging trends and current limitations, this review identifies key challenges and proposes future directions, including the refinement of antioxidant delivery systems, the development of multi-targeted approaches, and strategies to overcome the structural complexities of the spinal cord. This work underscores the pressing need for innovative and integrative therapeutic approaches to advance the clinical translation of antioxidant-based interventions and improve outcomes for SCI patients.

Synergic effect of combined xenogeneic mesenchymal stem cells and ceftriaxone on acute septic arthritis

BACKGROUND

This study tested the hypothesis that combined ceftriaxone (Cef) and human umbilical cord-derived mesenchymal stem cells (HUCDMSCs) was better than either therapy for alleviating acute septic arthritis (ASA).

METHODS AND RESULTS

Adult-male C57BL/6 mice were categorized into control group (Clt), group A (ASA only), group B [ASA + Cef (5 mg/kg, IM per day, at days 2 to 16 after ASA induction)], group C [ASA + HUCDMSCs (5 × 105 per mice at days 2, 3, 4 after ASA induction)], and group D (ASA + Cef + HUCDMSCs). Animals were euthanized by day 28. The result demonstrated that the body weight was significantly lower, whereas the ratio of kidney or spleen weight to WB, circulatory WBC count, bacterial colony-formation-unit from circulatory/kidney extraction were significantly higher in group A than in other groups (all P < .001). The proinflammatory cytokines (IL-6/TNF-α) of knee joint fluid were lowest in Clt and significantly and progressively reduced from groups A to D, whereas the circulatory levels of these 2 parameters at the time points of days 3/7/28 exhibited an identical pattern as knee joint fluid among the groups (all P-value < .0001). The scores of vertebral-bone destructions/inflamed synovium were lowest in Clt, highest in group A, significantly higher in group C than in groups B/D, and significantly higher in group C than in group D (all P < .0001).

CONCLUSION

Combined antibiotics and Cef and HUCDMSCs was superior to just one therapy for suppressing circulatory and tissue levels of inflammation and knee joint destruction in ASA.

Ameliorative effects of undifferentiated and differentiated BM-MSCs in MIA-induced osteoarthritic Wistar rats: roles of NF-κB and MMPs signaling pathways

OBJECTIVES

Osteoarthritis (OA) is a degenerative joint condition that is persistent. OA affects millions of people throughout the world. Both people and society are heavily economically burdened by osteoarthritis. There is currently no medication that can structurally alter the OA processes or stop the disease from progressing. Stem cells have the potential to revolutionize medicine due to their capacity to differentiate into chondrocytes, capacity to heal tissues and organs including osteoarthritic joints, and immunomodulatory capabilities. Therefore, the goal of the current investigation was to determine how bone marrow-derived mesenchymal stem cells (BM-MSCs) and chondrogenic differentiated mesenchymal stem cells (CD-MSCs) affected the treatment of OA in rats with monosodium iodoacetate (MIA)-induced osteoarthritis.

METHODS

Male Wistar rats were injected three times with MIA (1 mg)/100 µL isotonic saline to induce osteoarthritis in the ankle joint of the right hind leg. Following the MIA injection, the osteoarthritic rats were given weekly treatments of 1 × 106 BM-MSCs and CD-MSCs into the tail vein for three weeks.

RESULTS

The obtained results showed that in osteoarthritic rats, BM-MSCs and CD-MSCs dramatically decreased ankle diameter measurements, decreased oxidized glutathione (GSSG) level, and boosted glutathione peroxidase (GPx) and glutathione reductase (GR) activities. Additionally, in rats with MIA-induced OA, BM-MSCs and CD-MSCs dramatically boosted interleukin-10 (IL-10) serum levels while considerably decreasing serum anticitrullinated protein antibodies (ACPA), tumour necrosis factor-α (TNF-α), and interleukin-17 (IL-17) levels as well as ankle transforming growth factor-β1 (TGF-β1) expression. Analysis of histology, immunohistochemistry, and western blots in osteoarthritic joints showed that cartilage breakdown and joint inflammation gradually decreased over time.

CONCLUSIONS

It is possible to conclude from these results that BM-MSCs and CD-MSCs have anti-arthritic potential in MIA-induced OA, which may be mediated via inhibitory effects on oxidative stress, MMPs and inflammation through suppressing the NF-κB pathway. In osteoarthritis, using CD-MSCs as a treatment is more beneficial therapeutically than using BM-MSCs.

Improved Preservation of Rat Small Intestine Transplantation Graft by Introduction of Mesenchymal Stem Cell-Secreted Fractions

Segmental grafts from living donors have advantages over grafts from deceased donors when used for small intestine transplantation. However, storage time for small intestine grafts can be extremely short and optimal graft preservation conditions for short-term storage remain undetermined. Secreted factors from mesenchymal stem cells (MSCs) that allow direct activation of preserved small intestine grafts. Freshly excised Luc-Tg LEW rat tissues were incubated in preservation solutions containing MSC-conditioned medium (MSC-CM). Preserved Luc-Tg rat-derived grafts were then transplanted to wild-type recipients, after which survival, injury score, and tight junction protein expression were examined. Luminance for each graft was determined using in vivo imaging. The findings indicated that 30-100 and 3-10 kDa fractions of MSC-CM have superior activating effects for small intestine preservation. Expression of the tight-junction proteins claudin-3, and zonula occludens-1 preserved for 24 h in University of Wisconsin (UW) solution containing MSC-CM with 50-100 kDa, as shown by immunostaining, also indicated effectiveness. Reflecting the improved graft preservation, MSC-CM preloading of grafts increased survival rate from 0% to 87%. This is the first report of successful transplantation of small intestine grafts preserved for more than 24 h using a rodent model to evaluate graft preservation conditions that mimic clinical conditions.

Dexmedetomidine against intestinal ischemia/reperfusion injury: A systematic review and meta-analysis of preclinical studies

BACKGROUND

Intestinal ischemia/reperfusion injury (IRI) is a multifactorial, complex pathophysiological process in clinical settings. In recent years, intestinal IRI has received increasing attention due to increased morbidity and mortality. To date, there are no effective treatments. Dexmedetomidine (DEX), a highly selective α2-adrenergic receptor agonist, has been demonstrated to be effective against intestinal IRI. In this systematic review and meta-analysis, we evaluated the efficacy and potential mechanisms of DEX as a treatment for intestinal IRI in animal models.

METHODS

Five databases (PubMed, Embase, Web of Science, Cochrane Library, and Scopus) were searched until March 15, 2023. Using the SYRCLE risk bias tool, we assessed methodological quality. Statistical analysis was conducted using STATA 12 and R 4.2.2. We analyzed the related outcomes (mucosa damage-related indicators; inflammation-relevant markers, oxidative stress markers) relied on the fixed or random-effects models.

RESULTS

There were 15 articles including 18 studies included, and 309 animals were involved in the studies. Compared to the model groups, DEX improved intestinal IRI. DEX decreased Chiu's score and serum diamine oxidase (DAO) level. DEX reduced the level of inflammation-relevant markers (interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α). DEX also improved oxidative stress (decreased malondialdehyde (MDA), increased superoxide dismutase (SOD)).

CONCLUSIONS

DEX's effectiveness in ameliorating intestinal IRI has been demonstrated in animal models. Antioxidation, anti-inflammation, anti-apoptotic, anti-pyroptosis, anti-ferroptosis, enhancing mitophagy, reshaping the gut microbiota, and gut barrier protection are possible mechanisms. However, in light of the heterogeneity and methodological quality of these studies, further well-designed preclinical studies are warranted before clinical implication.

Interplay Between Inflammatory-immune and Interleukin-17 Signalings Plays a Cardinal Role on Liver Ischemia-reperfusion Injury-Synergic Effect of IL-17Ab, Tacrolimus and ADMSCs on Rescuing the Liver Damage

BACKGROUND

This study tested the hypothesis that inflammatory and interleukin (IL)-17 signalings were essential for acute liver ischemia (1 h)-reperfusion (72 h) injury (IRI) that was effectively ameliorated by adipose-derived mesenchymal stem cells (ADMSCs) and tacrolimus.

METHODS

Adult-male SD rats (n = 50) were equally categorized into groups 1 (sham-operated-control), 2 (IRI), 3 [IRI + IL-17-monoclonic antibody (Ab)], 4 (IRI + tacrolimus), 5 (IRI + ADMSCs) and 6 (IRI + tacrolimus-ADMSCs) and liver was harvested at 72 h.

RESULTS

The main findings included: (1) circulatory levels: inflammatory cells, immune cells, and proinflammatory cytokines as well as liver-damage enzyme at the time point of 72 h were highest in group 2, lowest in group 1 and significantly lower in group 6 than in groups 3 to 5 (all p < 0.0001), but they did not differ among these three latter groups; (2) histopathology: the liver injury score, fibrosis, inflammatory and immune cell infiltration in liver immunity displayed an identical pattern of inflammatory cells among the groups (all p < 0.0001); and (3) protein levels: upstream and downstream inflammatory signalings, oxidative-stress, apoptotic and mitochondrial-damaged biomarkers exhibited an identical pattern of inflammatory cells among the groups (all p < 0.0001).

CONCLUSION

Our results obtained from circulatory, pathology and molecular-cellular levels delineated that acute IRI was an intricate syndrome that elicited complex upstream and downstream inflammatory and immune signalings to damage liver parenchyma that greatly suppressed by combined tacrolimus and ADMSCs therapy.

Protective and therapeutic potential of melatonin against intestinal diseases: updated review of current data based on molecular mechanisms

INTRODUCTION

Intestinal diseases, a leading global cause of mortality and morbidity, carry a substantial socioeconomic burden. Small and large intestines play pivotal roles in gastrointestinal physiology and food digestion. Pathological conditions, such as gut dysbiosis, inflammation, cancer, therapy-related complications, ulcers, and ischemia, necessitate the urgent exploration of safe and effective complementary therapeutic strategies for optimal intestinal health.

AREAS COVERED

This article evaluates the potential therapeutic effects of melatonin, a molecule with a wide range of physiological actions, on intestinal diseases including inflammatory bowel disease, irritable bowel syndrome, colon cancer, gastric/duodenal ulcers and other intestinal disorders.

EXPERT OPINION

Due to anti-inflammatory and antioxidant properties as well as various biological actions, melatonin could be a therapeutic option for improving digestive disorders. However, more researches are needed to fully understand the potential benefits and risks of using melatonin for digestive disorders.

Adipose-derived mesenchymal stem cells overexpressing prion improve outcomes via the NLRP3 inflammasome/DAMP signalling after spinal cord injury in rat

Traumatic spinal cord injury (SCI) is a highly destructive disease in human neurological functions. Adipose-derived mesenchymal stem cells (ADMSCs) have tissue regenerations and anti-inflammations, especially with prion protein overexpression (PrPc^OE ). Therefore, this study tested whether PrPc^OE -ADMSCs therapy offered benefits in improving outcomes via regulating nod-like-receptor-protein-3 (NLRP3) inflammasome/DAMP signalling after acute SCI in rats. Compared with ADMSCs only, the capabilities of PrPc^OE -ADMSCs were significantly enhanced in cellular viability, anti-oxidative stress and migration against H₂ O₂ and lipopolysaccharide damages. Similarly, PrPc^OE -ADMSCs significantly inhibited the inflammatory patterns of Raw264.7 cells. The SD rats (n = 32) were categorized into group 1 (Sham-operated-control), group 2 (SCI), group 3 (SCI + ADMSCs) and group 4 (SCI + PrPc^OE -ADMSCs). Compared with SCI group 2, both ADMSCs and PrPc^OE -ADMSCs significantly improved neurological functions. Additionally, the circulatory inflammatory cytokines levels (TNF-α/IL-6) and inflammatory cells (CD11b/c+/MPO+/Ly6G+) were highest in group 2, lowest in group 1, and significantly higher in group 3 than in group 4. By Day 3 after SCI induction, the protein expressions of inflammasome signalling (HGMB1/TLR4/MyD88/TRIF/c-caspase8/FADD/p-NF-κB/NEK7/NRLP3/ASC/c-caspase1/IL-ß) and by Day 42 the protein expressions of DAMP-inflammatory signalling (HGMB1/TLR-4/MyD88/TRIF/TRAF6/p-NF-κB/TNF-α/IL-1ß) in spinal cord tissues displayed an identical pattern as the inflammatory patterns. In conclusion, PrPc^OE -ADMSCs significantly attenuated SCI in rodents that could be through suppressing the inflammatory signalling.

Integrin receptor-binding nanofibrous peptide hydrogel for combined mesenchymal stem cell therapy and nitric oxide delivery in renal ischemia/reperfusion injury

Background

Mesenchymal-based therapy has been utilized as a practical approach in the treatment of renal ischemia/reperfusion (I/R) injury. However, low cell retention and survival in the ischemic site have remained challenging issues. To bridge this gap, the integrin receptor-binding RGD peptide-functionalized, s-nitroso-n-acetyl penicillamine (SNAP)-loaded hydrogel was used to transplant Wharton's jelly-mesenchymal stem cells (WJ-MSCs).

Methods

Apart from physicochemical and rheological characterizations that confirmed entangled interlocking β-sheets with nanofibrous morphology, real-time RT-PCR, ROS production, serum biomarker concentrations, and histopathological alterations were explored in a mouse model to assess the therapeutic efficacy of formulations in the treatment of renal I/R injury.

Results

The RGD-functionalized Fmoc-diphenylalanine (Fmoc-FF + Fmoc-RGD) hydrogel supported the spread and proliferation of WJ-MSCs in vivo. Notably, intralesional injection of nitric oxide donor combined with the embedded WJ-MSCs caused superior recovery of renal I/R injury compared to free WJ-MSCs alone in terms of histopathological scores and renal function indices. Compared to the I/R control group, oxidative stress and inducible nitric oxide synthase (iNOS) expression biomarkers showed a significant decline, whereas endothelial nitric oxide synthase (eNOS) and vascular endothelial growth factor (VEGF) expression exhibited a significant increment, indicating regeneration of the injured endothelial tissue.

Conclusion

The findings confirmed that the hydrogels containing WJ-MSCs and nitric oxide donors can promote the regeneration of renal I/R injuries by increasing angiogenic factors and cell engraftment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03045-1.

Mesenchymal stem cells against intestinal ischemia-reperfusion injury: a systematic review and meta-analysis of preclinical studies

Background

Intestinal ischemia–reperfusion injury (IRI) causes localized and distant tissue lesions. Multiple organ failure is a common complication of severe intestinal IRI, leading to its high rates of morbidity and mortality. Thus far, this is poorly treated, and there is an urgent need for new more efficacious treatments. This study evaluated the beneficial effects of mesenchymal stem cells (MSCs) therapy on intestinal IRI using many animal experiments.

Methods

We conducted a comprehensive literature search from 4 databases: Pubmed, Embase, Cochrane library, and Web of science. Primary outcomes included the survival rate, Chiu’s score, intestinal levels of IL-6, TNF-α and MDA, as well as serum levels of DAO, D-Lactate, and TNF-α. Statistical analysis was carried out using Review Manager 5.3.

Results

It included Eighteen eligible researches in the final analysis. We demonstrated that survival rates in animals following intestinal IRI were higher with MSCs treatment compared to vehicle treatment. Besides, MSCs treatment attenuated intestinal injury caused by IRI, characterized by lower Chiu’s score (− 1.96, 95% CI − 2.72 to − 1.19, P < 0.00001), less intestinal inflammation (IL-6 (− 2.73, 95% CI − 4.19 to − 1.27, P = 0.0002), TNF-α (− 3.00, 95% CI − 4.74 to − 1.26, P = 0.0007)) and oxidative stress (MDA (− 2.18, 95% CI − 3.17 to − 1.19, P < 0.0001)), and decreased serum levels of DAO (− 1.39, 95% CI − 2.07 to − 0.72, P < 0.0001), D-Lactate (− 1.54, 95% CI − 2.18 to − 0.90, P < 0.00001) and TNF-α (− 2.42, 95% CI − 3.45 to − 1.40, P < 0.00001). The possible mechanism for MSCs to treat intestinal IRI might be through reducing inflammation, alleviating oxidative stress, as well as inhibiting the apoptosis and pyroptosis of the intestinal epithelial cells.

Conclusions

Taken together, these studies revealed that MSCs as a promising new treatment for intestinal IRI, and the mechanism of which may be associated with inflammation, oxidative stress, apoptosis, and pyroptosis. However, further studies will be required to confirm these findings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02896-y.

Valsartan- and melatonin-supported adipose-derived mesenchymal stem cells preserve renal function in chronic kidney disease rat through upregulation of prion protein participated in promoting PI3K-Akt-mTOR signaling and cell proliferation

This study tested the hypothesis that valsartan (Val) and melatonin (Mel)-assisted adipose-derived mesenchymal stem cells (ADMSCs) preserved the residual renal function in chronic kidney disease (CKD) rat through promoting cellular-prior-protein (PrP^C) to upregulate PI3K/Akt/mTOR signaling and cell proliferation. In vitro study demonstrated that as compared with CKD-derived-ADMSCs, Val/Mel/overexpression of PrP^C-treated CKD derived-ADMSCs significantly upregulated cell proliferation and protein expressions of PrP^C and phosphorylated (p)-PI3K/p-Akt/p-mTOR, and downregulated oxidative stress (all p < 0.001). Rats (n = 42) were categorized into group 1 (sham-operated-control), group 2 (CKD), group 3 (CKD + ADMSCs/1.2 ×10⁶ cells) + Mel/20 mg/kg/day), group 4 (CKD + siRNA-PrP^C-ADMSCs/1.2 ×10⁶ cells), group 5 (CKD + ADMSCs/1.2 ×10⁶ cells + Val/20 mg/kg/day) and group 6 (CKD + Val + Mel). By day 35, the kidney specimens were harvested and the result showed that the protein expression of PrP^C was highest in group 1, lowest in groups 2/4 and significantly lower in group 6 than in groups 3/5, but it was similar in groups 3/5 (all p < 0.0001). The protein expressions of cell-stress-signaling (p-PI3K/p-Akt/p-mTOR) and cell-cycle activity (cyclin-D1/clyclin-E2/Cdk2/Cdk4) exhibited an identical pattern, whereas the protein expressions of oxidative-stress (NOX-1/NOX-2)/mitochondrial fission (PINK1/DRP1)/apoptosis (cleaved-capsase3/cleaved-PARP) and fibrosis (TFG-ß/Smad3) as well as creatinine/BUN levels, ratio of urine-protein to urine-creatine and kidney-injured score exhibited an opposite pattern of PrP^C among the groups (all p < 0.0001). In conclusion, Mel/Val facilitated-ADMSCs preserved renal architecture and function in CKD rat through promoting PrP^C to regulate the cell proliferation/oxidative-stress/cell-stress signalings.

Potentiating the Benefits of Melatonin through Chemical Functionalization: Possible Impact on Multifactorial Neurodegenerative Disorders

Although melatonin is an astonishing molecule, it is possible that chemistry will help in the discovery of new compounds derived from it that may exceed our expectations regarding antioxidant protection and perhaps even neuroprotection. This review briefly summarizes the significant amount of data gathered to date regarding the multiple health benefits of melatonin and related compounds. This review also highlights some of the most recent directions in the discovery of multifunctional pharmaceuticals intended to act as one-molecule multiple-target drugs with potential use in multifactorial diseases, including neurodegenerative disorders. Herein, we discuss the beneficial activities of melatonin derivatives reported to date, in addition to computational strategies to rationally design new derivatives by functionalization of the melatonin molecular framework. It is hoped that this review will promote more investigations on the subject from both experimental and theoretical perspectives.

Effect of Melatonin for Regulating Mesenchymal Stromal Cells and Derived Extracellular Vesicles

Melatonin is a hormone, synthesized in the pineal gland, which primarily controls the circadian rhythm of the body. In recent years, melatonin has also been shown to regulate metabolism, provide neuroprotection, and act as an anti-inflammatory, free radical scavenger. There has also been a recent research interest in the role of melatonin in regulating mesenchymal stromal cells (MSCs). MSCs are pivotal for their ability to differentiate into a variety of different tissues. There is also increasing evidence for the therapeutic prospects of MSCs via paracrine signaling. In addition to secreting cytokines and chemokines, MSCs can secrete extracellular vesicles (EVs), allowing them to respond to injury and promote tissue regeneration. While there has been a major research interest in the use of MSCs for regenerative medicine, the clinical application is limited by many risks, including tumorigenicity, senescence, and sensitivity to toxic environments. The use of MSC-derived EVs for cell-free therapy can potentially avoid the disadvantages of MSCs, which makes this an exciting prospect for regenerative medicine. Prior research has shown that MSCs, via paracrine mechanisms, can identify receptor-independent responses to melatonin and then activate a series of downstream pathways, which exert a variety of effects, including anti-tumor and anti-inflammatory effects. Here we review the synthesis of melatonin, its mechanisms of action, and the effect of melatonin on MSCs via paracrine signaling. Furthermore, we summarize the current clinical applications of melatonin and discuss future prospects.

Xenogeneic and Allogeneic Mesenchymal Stem Cells Effectively Protect the Lung Against Ischemia-reperfusion Injury Through Downregulating the Inflammatory, Oxidative Stress, and Autophagic Signaling Pathways in Rat

This study tested the hypothesis that both allogenic adipose-derived mesenchymal stem cells (ADMSCs) and human inducible pluripotent stem cell-derived MSCs (iPS-MSCs) offered a comparable effect for protecting the lung against ischemia-reperfusion (IR) injury in rodent through downregulating the inflammatory, oxidative stress, and autophagic signaling pathways. Adult male Sprague–Dawley rats (n = 32) were categorized into group 1 (sham-operated control), group 2 (IRI), group 3 [IRI + ADMSCs (1.0 × 10⁶ cells)/tail-vein administration at 0.5/18/36 h after IR], and group 4 [IRI + iPS-MSCs (1.0 × 10⁶ cells)/tail-vein administration at 0.5/18/36 h after IR], and lungs were harvested at 72 h after IR procedure. In vitro study demonstrated that protein expressions of three signaling pathways in inflammation (TLR4/MyD88/TAK1/IKK/I-κB/NF-κB/Cox-2/TNF-α/IL-1ß), mitochondrial damage/cell apoptosis (cytochrome C/cyclophilin D/DRP1/ASK1/APAF-1/mitochondrial-Bax/caspase3/8/9), and autophagy/cell death (ULK1/beclin-1/Atg5,7,12, ratio of LCB3-II/LC3B-I, p-AKT/m-TOR) were significantly higher in lung epithelial cells + 6h hypoxia as compared with the control, and those were significantly reversed by iPS-MSC treatment (all P < 0.001). Flow cytometric analysis revealed that percentages of the inflammatory cells in bronchioalveolar lavage fluid and circulation, and immune cells in circulation/spleen as well as circulatory early and late apoptotic cells were highest in group 2, lowest in group 1, and significantly higher in group 3 than in group 4 (all P < 0.0001). Microscopy showed the lung injury score and numbers of inflammatory cells and Western blot analysis showed the signaling pathways of inflammation, mitochondrial damage/cell apoptosis, autophagy, and oxidative stress exhibited an identical pattern of flow cytometric results among the four groups (all P < 0.0001). Both xenogeneic and allogenic MSCs protected the lung against IRI via suppressing the inflammatory, oxidative stress, and autophagic signaling.

Effects of different doses of melatonin on rat adipose derived mesenchymal stem cells

OBJECTIVES

Stem cell treatment is based on Melatonin which is crucial for lots of pathological and physiological pathways. Our aim is determining the most appropriate dose of melatonin affecting the rat adipose tissue mesenchymal stem cells.

METHODS

Stem cells were isolated from male rat adipose tissue. Differentiation and characterization experiments were performed. Cell viability analyses in stem cells were used the XTT [2,3-Bis-(2-methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide] assay. After 24 h incubation, different concentrations (0.5, 1, 5, 10, 50 µM) of extract were treated to the stem cells for 24 h, 48 and 72 h considering time and dose dependent manner. Total antioxidant status (TAS) and the total oxidant status (TOS) in control cells and melatonin treated cells (5, 10 µM) were determined Rel Assay commercial kits.

RESULTS

In 24 h, melatonin increased cell viability in all groups. When we evaluate the effect of melatonin in 48 h, the most proliferation increase was seen at 5, 10 µM doses. When the total oxidant activity melatonin was found to be significantly lower in 5 and 10 µM dose groups of melatonin.

CONCLUSIONS

Melatonin increases the survivor of stem cells and the most effective dose is 5 and 10 µM. The reduction of the oxidative stress index as a result of treating melatonin to mesenchymal stem cells showed that melatonin is a powerful antioxidant for stem cells.

Human Umbilical Cord-Derived Mesenchymal Stem Cells for Acute Respiratory Distress Syndrome

OBJECTIVES

To investigate the safety, feasibility, and possible adverse events of single-dose human umbilical cord-derived mesenchymal stem cells in patients with moderate-to-severe acute respiratory distress syndrome.

DESIGN

Prospective phase I clinical trial.

SETTING

Medical center in Kaohsiung, Taiwan.

PATIENTS

Moderate-to-severe acute respiratory distress syndrome with a PaO2/FIO2 ratio less than 200.

INTERVENTIONS

Scaling for doses was required by Taiwan Food and Drug Administration as follows: the first three patients received low-dose human umbilical cord-derived mesenchymal stem cells (1.0 × 10 cells/kg), the next three patients with intermediate dose (5.0 × 10 cells/kg), and the final three patients with high dose (1.0 × 10 cells/kg) between December 2017 and August 2019.

MEASUREMENTS AND MAIN RESULTS

Nine consecutive patients were enrolled into the study. In-hospital mortality was 33.3% (3/9), including two with recurrent septic shock and one with ventilator-induced severe pneumomediastinum and subcutaneous emphysema. No serious prespecified cell infusion-associated or treatment-related adverse events was identified in any patient. Serial flow-cytometric analyses of circulating inflammatory biomarkers (CD14CD33/CD11b+CD16+/CD16+MPO+/CD11b+MPO+/CD14CD33+) and mesenchymal stem cell markers (CD26+CD45-/CD29+CD45-/CD34+CD45-/CD44+CD45-/CD73+CD45-/CD90+CD45-/CD105+CD45-/CD26+CD45-) were notably progressively reduced (p for trend < 0.001), whereas the immune cell markers (Helper-T-cell/Cytotoxity-T-cell/Regulatory-T-cell) were notably increased (p for trend < 0.001) after cell infusion.

CONCLUSIONS

The result of this phase I clinical trial showed that a single-dose IV infusion of human umbilical cord-derived mesenchymal stem cells was safe with favorable outcome in nine acute respiratory distress syndrome patients.

Umbilical cord-derived MSC and hyperbaric oxygen therapy effectively protected the brain in rat after acute intracerebral haemorrhage

This study tested the hypothesis that combined therapy with human umbilical cord‐derived mesenchymal stem cells (HUCDMSCs) and hyperbaric oxygen (HBO) was superior to either one on preserving neurological function and reducing brain haemorrhagic volume (BHV) in rat after acute intracerebral haemorrhage (ICH) induced by intracranial injection of collagenase. Adult male SD rats (n = 30) were equally divided into group 1 (sham‐operated control), group 2 (ICH), group 3 (ICH +HUCDMSCs/1.2 × 10⁶ cells/intravenous injection at 3h and days 1 and 2 after ICH), group 4 (ICH +HBO/at 3 hours and days 1 and 2 after ICH) and group 5 (ICH +HUCDMSCs‐HBO), and killed by day 28 after ICH. By day 1, the neurological function was significantly impaired in groups 2‐5 than in group 1 (P < .001), but it did not differ among groups 2 to 5. By days 7, 14 and 28, the integrity of neurological function was highest in group 1, lowest in group 2 and significantly progressively improved from groups 3 to 5 (all P < .001). By day 28, the BHV was lowest in group 1, highest in group 2 and significantly lower in group 5 than in groups 3/4 (all P < .0001). The protein expressions of inflammation (HMGB1/TLR‐2/TLR‐4/MyD88/TRAF6/p‐NF‐κB/IFN‐γ/IL‐1ß/TNF‐α), oxidative stress/autophagy (NOX‐1/NOX‐2/oxidized protein/ratio of LC3B‐II/LC3B‐I) and apoptosis (cleaved‐capspase3/PARP), and cellular expressions of inflammation (CD14+, F4/80+) in brain tissues exhibited an identical pattern, whereas cellular levels of angiogenesis (CD31+/vWF+/small‐vessel number) and number of neurons (NeuN+) exhibited an opposite pattern of BHV among the groups (all P < .0001). These results indicate that combined HUCDMSC‐HBO therapy offered better outcomes after rat ICH.

Melatonin Attenuates Sepsis-Induced Small-Intestine Injury by Upregulating SIRT3-Mediated Oxidative-Stress Inhibition, Mitochondrial Protection, and Autophagy Induction

Melatonin reportedly alleviates sepsis-induced multi-organ injury by inducing autophagy and activating class III deacetylase Sirtuin family members (SIRT1-7). However, whether melatonin attenuates small-intestine injury along with the precise underlying mechanism remain to be elucidated. To investigate this, we employed cecal ligation and puncture (CLP)- or endotoxemia-induced sepsis mouse models and confirmed that melatonin treatment significantly prolonged the survival time of mice and ameliorated multiple-organ injury (lung/liver/kidney/small intestine) following sepsis. Melatonin partially protected the intestinal barrier function and restored SIRT1 and SIRT3 activity/protein expression in the small intestine. Mechanistically, melatonin treatment enhanced NF-κB deacetylation and subsequently reduced the inflammatory response and decreased the TNF-α, IL-6, and IL-10 serum levels; these effects were abolished by SIRT1 inhibition with the selective blocker, Ex527. Correspondingly, melatonin treatment triggered SOD2 deacetylation and increased SOD2 activity and subsequently reduced oxidative stress; this amelioration of oxidative stress by melatonin was blocked by the SIRT3-selective inhibitor, 3-TYP, and was independent of SIRT1. We confirmed this mechanistic effect in a CLP-induced sepsis model of intestinal SIRT3 conditional-knockout mice, and found that melatonin preserved mitochondrial function and induced autophagy of small-intestine epithelial cells; these effects were dependent on SIRT3 activation. This study has shown, to the best of our knowledge, for the first time that melatonin alleviates sepsis-induced small-intestine injury, at least partially, by upregulating SIRT3-mediated oxidative-stress inhibition, mitochondrial-function protection, and autophagy induction.

Combinatory Effects of Bone Marrow-Derived Mesenchymal Stem Cells and Indomethacin on Adjuvant-Induced Arthritis in Wistar Rats: Roles of IL-1β, IL-4, Nrf-2, and Oxidative Stress

Rheumatoid arthritis (RA) is a disorder triggered by autoimmune reactions and related with chronic inflammation and severe disability. Bone Marrow-derived Mesenchymal Stem Cells (BM-MSCs) have shown a hopeful immunomodulatory effect towards repairing cartilage and restoring joint function. Additionally, indomethacin (IMC), a nonsteroidal compound, has been considered as a potent therapeutic agent that exhibits significant antipyretic properties and analgesic effects. The target of the current research is to assess the antiarthritic efficacy of BM-MSCs (10⁶ cells/rat at 1, 6, 12 and 18 days) and IMC (2 mg/kg body weight/day for 3 weeks) either alone or concurrently administered against complete Freund's adjuvant-induced arthritic rats. Changes in paw volume, body weight, gross lesions, and antioxidant defense system, as well as oxidative stress, were assessed. The Th1 cytokine (IL-1β) serum level and Th2 cytokine (IL-4) and Nrf-2 ankle joint expression were detected. In comparison to normal rats, it was found that the CFA-induced arthritic rats exhibited significant leukocytosis and increase in paw volume, LPO level, RF, and IL-1β serum levels. In parallel, arthritic rats that received BM-MSCs and/or IMC efficiently exhibited decrease in paw edema, leukocytosis, and enhancement in the antioxidant enzymatic levels of SOD, GPx, GST, and GSH in serum besides upregulation of Nrf-2 and anti-inflammatory IL-4 expression levels in the ankle articular joint. Likewise, these analyses were more evidenced by the histopathological sections and histological score. The data also revealed that the combined administration of BM-MSC and IMC was more potent in suppressing inflammation and enhancing the anti-inflammatory pathway than each agent alone. Thus, it can be concluded that the combined therapy with BM-MSC and IMC may be used as a promising therapeutic choice after assessing their efficacy and safety in human beings with RA, and the antiarthritic effects may be mediated via modulatory effects on Th1/Th2 cytokines, ozidative stress, and Nrf-2.

circ-PRKCB acts as a ceRNA to regulate p66Shc-mediated oxidative stress in intestinal ischemia/reperfusion

Background: Oxidative stress has emerged as an essential factor in the pathogenesis of intestinal ischemia/reperfusion (I/R) injury. The adaptor protein p66Shc is a key regulator of reactive oxygen species (ROS) generation and a mediator of I/R damage in the intestine, but the upstream mechanisms that directly regulate p66Shc expression during intestinal I/R remain largely unknown. Recent studies have suggested that noncoding RNAs, such as circular RNAs (circRNAs), are important players in physiological and pathological processes based on their versatile regulatory roles in gene expression. The aim of this study was to elucidate the contribution of p66Shc to oxidative damage in intestinal I/R and to investigate the regulation of p66Shc by circRNA sponges.

Methods: Intestinal I/R was induced in mice via superior mesenteric artery (SMA) occlusion. A miR-339-5p agomir or circ-protein kinase C beta (PRKCB) siRNA was injected intravenously before I/R challenge. In addition, Caco-2 cells were subjected to hypoxia/reoxygenation (H/R) in vitro to simulate an in vivo I/R model.

Results:In vitro, p66Shc deficiency significantly reduced H/R-induced ROS overproduction by attenuating mitochondrial superoxide anion (O₂^-) levels, suppressing NADPH oxidase activity and enhancing antioxidant enzyme expression. Moreover, miR-339-5p was identified to directly regulate p66Shc expression in the intestine. Furthermore, we found that a circRNA transcribed from the PRKCB gene, named circ-PRKCB, acted as an endogenous miR-339-5p sponge to regulate p66Shc expression. circ-PRKCB silencing or miR-339-5p overexpression significantly downregulated p66Shc expression and attenuated oxidative stress levels and I/R injury in vivo and in vitro. Notably, the increased circ-PRKCB levels and decreased miR-339-5p levels associated with murine intestinal I/R were consistent with those in patients with intestinal infarction.

Conclusions: Our findings reveal a crucial role for the circ-PRKCB/miR-339-5p/p66Shc signaling pathway in regulating oxidative stress in the I/R intestine. This pathway may be a potential therapeutic target for intestinal I/R injury.

Combination therapy with melatonin, stem cells and extracellular vesicles is effective in limiting renal ischemia-reperfusion injury in a rat model

OBJECTIVE

To evaluate the therapeutic value of melatonin, mesenchymal stem cells and their extracellular vesicles, exosomes, on renal ischemia-reperfusion.

METHODS

Female albino rats (n = 64) were divided into eight groups (n = 8 per group): control, sham (only laparotomy), renal ischemia-reperfusion (renal ischemia-reperfusion + phosphate-buffered saline), melatonin (renal ischemia-reperfusion + melatonin), mesenchymal stem cells (renal ischemia-reperfusion + mesenchymal stem cells), exosomes (renal ischemia-reperfusion + exosomes), melatonin + mesenchymal stem cells (renal ischemia-reperfusion + melatonin + mesenchymal stem cells) and melatonin + exosomes (renal ischemia-reperfusion + melatonin + exosomes). After the establishment of the renal ischemia-reperfusion model, rats in each group were bilaterally injected once with either mesenchymal stem cells or exosomes in both renal arteries during reperfusion.

RESULTS

Notable improvement of renal ischemia-reperfusion was obtained after different treatments, as evidenced by a lower histopathological score of kidney injury; decreased serum levels of urea, creatinine and retinol-binding protein; reduced lipid peroxidation marker malondialdehyde; increased superoxide dismutase and catalase activities; reduced apoptosis (lower DNA damage and B-cell lymphoma 2-associated X protein, and higher B-cell lymphoma 2 genes/proteins); and inhibition of kidney inflammatory and damage markers (tumor necrosis alpha, interleukin-1β, nuclear factor kappa B, kidney injury molecule-1, IL-18, matrix metalloproteinase 9, neutrophil gelatinase-associated lipocalin). The improvement order was (highest to lowest): melatonin + exosomes, melatonin + mesenchymal stem cells, exosomes, mesenchymal stem cells and melatonin group.

CONCLUSIONS

Our data suggest a potential therapeutic effect of combined therapy with melatonin, mesenchymal stem cells and their exosomes to minimize renal ischemia-reperfusion injury in rats.

IL-37 Gene Modification Enhances the Protective Effects of Mesenchymal Stromal Cells on Intestinal Ischemia Reperfusion Injury

Background

Ischemia reperfusion injury (IRI) is the major cause of intestinal damage in clinic. Although either mesenchymal stromal cells (MSCs) or interleukin 37 (IL-37) shows some beneficial roles to ameliorate IRI, their effects are limited. In this study, the preventative effects of IL-37 gene-modified MSCs (IL-37-MSCs) on intestinal IRI are investigated.

Methods

Intestinal IRI model was established by occluding the superior mesenteric artery for 30 minutes and then reperfused for 72 hours in rats. Forty adult male Sprague-Dawley rats were randomly divided into the sham control, IL-37-MSC-treated, MSC-treated, recombinant IL-37- (rIL-37-) treated, and untreated groups. Intestinal damage was assessed by H&E staining. The levels of gut barrier function factors (diamine oxidase and D-Lactate) and inflammation cytokine IL-1β were assayed using ELISA. The synthesis of tissue damage-related NLRP3 inflammasome and downstream cascade reactions including cleaved caspase-1, IL-1β, and IL-18 was detected by western blot. The mRNA levels of proinflammatory mediators IL-6 and TNF-α, which are downstream of IL-1β and IL-18, were determined by qPCR. Data were analyzed by one-way analysis of variance (ANOVA) after the normality test and followed by post hoc analysis with the least significant difference (LSD) test.

Results

IL-37-MSCs were able to migrate to the damaged tissue and significantly inhibit intestinal IRI. As compared with MSCs or the rIL-37 monotherapy group, IL-37-MSC treatment both improved gut barrier function and decreased local and systemic inflammation cytokine IL-1β level in IRI rats. In addition, tissue damage-related NLRP3 and downstream targets (cleaved caspase-1, IL-1β, and IL-18) were significantly decreased in IRI rats treated with IL-37-MSCs. Furthermore, IL-1β- and IL-18-related proinflammatory mediator IL-6 and TNF-α mRNA expressions were all significantly decreased in IRI rats treated with IL-37-MSCs.

Conclusion

The results suggest that IL-37 gene modification significantly enhances the protective effects of MSCs against intestinal IRI. In addition, NLRP3-related signaling pathways could be associated with IL-37-MSC-mediated protection.

Hepatic 31 P-magnetic resonance spectroscopy identified the impact of melatonin-pretreated mitochondria in acute liver ischaemia-reperfusion injury

Acute liver ischaemia-reperfusion injury (IRI), commonly encountered during liver resection and transplantation surgery, is strongly associated with unfavourable clinical outcome. However, a prompt and accurate diagnosis and the treatment of this entity remain formidable challenges. This study tested the hypothesis that ³¹ P-magnetic resonance spectroscopy (³¹ P-MRS) findings could provide reliable living images to accurately identify the degree of acute liver IRI and melatonin-pretreated mitochondria was an innovative treatment for protecting the liver from IRI in rat. Adult male SD rats were categorized into group 1 (sham-operated control), group 2 (IRI only) and group 3 (IRI + melatonin [ie mitochondrial donor rat received intraperitoneal administration of melatonin] pretreated mitochondria [10 mg/per rat by portal vein]). By the end of study period at 72 hours, ³¹ P-MRS showed that, as compared with group 1, the hepatic levels of ATP and NADH were significantly lower in group 2 than in groups 1 and 3, and significantly lower in group 3 than in group 1. The liver protein expressions of mitochondrial-electron-transport-chain complexes and mitochondrial integrity exhibited an identical pattern to ³¹ P-MRS finding. The protein expressions of oxidative stress, inflammatory, cellular stress signalling and mitochondrial-damaged biomarkers displayed an opposite finding of ³¹ P-MRS, whereas the protein expressions of antioxidants were significantly progressively increased from groups 1 to 3. Microscopic findings showed that the fibrotic area/liver injury score and inflammatory and DNA-damaged biomarkers exhibited an identical pattern of cellular stress signalling. Melatonin-pretreated mitochondria effectively protected liver against IRI and ³¹ P-MRS was a reliable tool for measuring the mitochondrial/ATP consumption in living animals.

The emerging antioxidant paradigm of mesenchymal stem cell therapy

Mesenchymal stem cells (multipotent stromal cells; MSCs) have been under investigation for the treatment of diverse diseases, with many promising outcomes achieved in animal models and clinical trials. The biological activity of MSC therapies has not been fully resolved which is critical to rationalizing their use and developing strategies to enhance treatment efficacy. Different paradigms have been constructed to explain their mechanism of action, including tissue regeneration, trophic/anti-inflammatory secretion, and immunomodulation. MSCs rarely engraft and differentiate into other cell types after in vivo administration. Furthermore, it is equivocal whether MSCs function via the secretion of many peptide/protein ligands as their therapeutic properties are observed across xenogeneic barriers, which is suggestive of mechanisms involving mediators conserved between species. Oxidative stress is concomitant with cellular injury, inflammation, and dysregulated metabolism which are involved in many pathologies. Growing evidence supports that MSCs exert antioxidant properties in a variety of animal models of disease, which may explain their cytoprotective and anti-inflammatory properties. In this review, evidence of the antioxidant effects of MSCs in in vivo and in vitro models is explored and potential mechanisms of these effects are discussed. These include direct scavenging of free radicals, promoting endogenous antioxidant defenses, immunomodulation via reactive oxygen species suppression, altering mitochondrial bioenergetics, and donating functional mitochondria to damaged cells. Modulation of the redox environment and oxidative stress by MSCs can mediate their anti-inflammatory and cytoprotective properties and may offer an explanation to the diversity in disease models treatable by MSCs and how these mechanisms may be conserved between species.

Elucidating the Regulatory Role of Melatonin in Brown, White, and Beige Adipocytes

The high prevalence of obesity and its associated metabolic diseases has heightened the importance of understanding control of adipose tissue development and energy metabolism. In mammals, 3 types of adipocytes with different characteristics and origins have been identified: white, brown, and beige. Beige and brown adipocytes contain numerous mitochondria and have the capability to burn energy and counteract obesity, while white adipocytes store energy and are closely associated with metabolic disorders and obesity. Thus, regulation of the development and function of different adipocytes is important for controlling energy balance and combating obesity and related metabolic disorders. Melatonin is a neurohormone, which plays multiple roles in regulating inflammation, blood pressure, insulin actions, and energy metabolism. This article summarizes and discusses the role of melatonin in white, beige, and brown adipocytes, especially in affecting adipogenesis, inducing beige formation or white adipose tissue browning, enhancing brown adipose tissue mass and activities, improving anti-inflammatory and antioxidative effects, regulating adipokine secretion, and preventing body weight gain. Based on the current findings, melatonin is a potential therapeutic agent to control energy metabolism, adipogenesis, fat deposition, adiposity, and related metabolic diseases.

Combined Adipose-Derived Mesenchymal Stem Cells and Low-Energy Extracorporeal Shock Wave Therapy Protect the Brain From Brain Death-Induced Injury in Rat

This study tested the hypothesis that combined adipose-derived mesenchymal stem cell (ADMSC) and low-energy extracorporeal shock wave (ECSW) therapy could protect brain from brain death (BD)-induced injury. Adult male Sprague Dawley rats were categorized into group 1 (sham control), group 2 (BD), group 3 (BD + ECSW [0.15 mJ/mm2/300 impulses] applied to the skull surface 3 hours after BD induction), group 4 (BD + ADMSC [1.2 × 106 cell] by intravenous injection 3 hours after BD induction) and group 5 (BD + ECSW + ADMSC). By 6 hours after BD induction, circulating/spleen levels of immune cells (CD3/CD4+, CD8/CD4+, Treg+) and circulating levels of inflammatory cells (MPO/Ly6G/CD11a/b) and soluble mediators (TNF-α/IL-6) were lowest in group 1 and significantly progressively reduced from groups 2 to 5 (all p < 0.0001). Brain protein expressions of inflammatory (TNF-α/NF-κB/MMP-9/IL-1β), apoptotic (caspase-3/PARP/mitochondrial-BAX), oxidative stress/DNA-damage (NOX-1/NOX-2/oxidized protein/γ-H2AX) biomarkers exhibited an identical pattern, whereas anti-oxidant (SIRT1/SIRT3) and mitochondrial-integrity (mitochondrial-cytochrome-C) biomarkers exhibited an opposite pattern to inflammatory biomarkers among the 5 groups (all p < 0.0001). The cellular expressions of inflammatory/brain-edema (F4/80/CD14+/GFAP/AQP4) biomarkers exhibited an identical pattern to inflammation among the 5 groups (all p < 0.0001). In conclusion, ECSW-ADMSC therapy is superior to either alone for attenuating brain from BD-induced damage.

The potential therapeutic effect for melatonin and mesenchymal stem cells on hepatocellular carcinoma

BACKGROUND/AIM

Herein, we investigated the potential therapeutic effect of Melatonin (Mel) and/or mesenchymal stem cells (MSCs) on rat model of HCC.

MATERIALS AND METHODS

Female mature rats were divided into 5 groups (n = 10/group): normal (Nor), HCC group intraperitoneally injected with 200 mg/kg DEN, and 3 treated groups; HCC + Mel (Mel) group given Mel intraperitoneally 20 mg/kg, twice a week, HCC + MSCs (MSCs) group intravenously injected by 1 × 10⁶ cells, and HCC + MSCs (Mel +MSCs) group.

RESULTS

Rats in HCC group showed most deteriorated effect in form of increased mortality and relative liver weight, elevated serum levels of ALT, AST, ALP, AFP and GGT in addition to increased pre-neoplastic nodules in liver tissues. Liver tissues of HCC group also exhibited lower level of apoptosis as indicated by decreased DNA fragmentation and expression of p53 caspase 9 and caspase 3 genes and increased PCNA immunoreactivity. Moreover, in this group the expression of IL6 and TGFβ1 genes was significantly upregulated. All these deleterious effects induced by DEN were reversed after administration of Mel and/ or MSCs with best improvement for the combined group (MSCs + Mel).

CONCLUSIONS

These findings reveal a better therapeutic effect for MSCs when given with Mel and we attribute this beneficial effect, at least in part, to triggering apoptosis and targeting inflammation in HCC. Therefore, combined treatment with Mel and MSCs is recommended to enhance the therapeutic potential against HCC.

The HO-1-expressing bone mesenchymal stem cells protects intestine from ischemia and reperfusion injury

BACKGROUND

Bone mesenchymal stromal cells (BMSC) showed protective potential against intestinal ischemia. Oxygenase-1(HO-1) could alleviate oxidative stress. In the present study, we constructed HO-1-expressing BMSC and detected the effects of it on survival, intestinal injury and inflammation following intestinal ischemia and reperfusion injury (I/R).

METHODS

In this experiment, eighty adult male mice were divided into Sham, I/R, I/R + BMSC, I/R + BMSC/HO-1 groups. Mice were anesthetized and intestinal I/R model were established by temporarily occluding the superior mesenteric artery for 60 min with a non-crushing clamp. Following ischemia, the clamp was removed and the intestines were allowed for reperfusion. Prior to abdominal closure, BMSC/ HO-1 (2 × 10⁶ cells) or BMSC (2 × 10⁶ cells) were injected into the peritoneum of I/R mice respectively. Mice were allowed to recover for 24 h and then survival rate, intestinal injury and inflammation were determined. Reactive oxygen species (ROS) was assayed by fluorescent probe. TNFα and IL-6 were assayed by ELISA.

RESULTS

BMSC/HO-1 increased seven day survival rate, improved intestinal injury and down-regulated inflammation after intestinal I/R when compared with sole BMSC (p < 0.05 respectively). Multiple pro-inflammatory media were also decreased following application of BMSC/HO-1, when compared with sole BMSC (p < 0.05) respectively, suggesting that BMSC /HO-1 had a better protection to intestinal I/R than BMSC therapy.

CONCLUSION

Administration of BMSC/HO-1 following intestinal I/R, significantly improved intestinal I/R by limiting intestinal damage and inflammation.

Melatonin Treatment Alleviates Spinal Cord Injury-Induced Gut Dysbiosis in Mice

Spinal cord injury (SCI) disturbs the autonomic nervous system and induces dysfunction in multiple organs/tissues, such as the gastrointestinal (GI) system. The neuroprotective effects of melatonin in SCI models have been reported; however, it is unclear whether the beneficial effects of melatonin are associated with alleviation of gut dysbiosis. In this study, we showed that daily intraperitoneal injection with melatonin following spinal cord contusion at thoracic level 10 in mice improved intestinal barrier integrity and GI motility, reduced expression levels of certain proinflammatory cytokines, improved animal weight gain and metabolic profiling, and promoted locomotor recovery. Analysis of gut microbiome revealed that melatonin treatment decreased the Shannon index and reshaped the composition of intestinal microbiota. Melatonin-treated SCI animals showed decreased relative abundance of Clostridiales and increased relative abundance of Lactobacillales and Lactobacillus, which correlated with alteration of cytokine (monocyte chemotactic protein 1) expression and GI barrier permeability, as well as with locomotor recovery. Experimental induction of gut dysbiosis in mice before SCI (i.e., by oral delivery of broad-spectrum antibiotics) exacerbates neurological impairment after SCI, and melatonin treatment improves locomotor performance and intestinal integrity in antibiotic-treated SCI mice. The results suggest that melatonin treatment restores SCI-induced alteration in gut microbiota composition, which may underlie the ameliorated GI function and behavioral manifestations.

Melatonin maximizes the therapeutic potential of non-preconditioned MSCs in a DEN-induced rat model of HCC

Pretreatment of mesenchymal stem cells (MSCs) with melatonin (Mel) improves their potential therapeutic effect on chronic diseases and cancers. However, this preconditioning strategy may direct the effect of Mel toward MSCs alone and deprive cancer cells of the oncostatic effect of Mel. Herein, we hypothesized that Mel given before transplantation of non-preconditioned MSCs may maximize the therapeutic outcome via the oncostatic effect of Mel by preparing a suitable tumor microenvironment for MSCs. Female rats (n = 60) were equally divided into 6 groups; normal control, diethylnitrosamine (DEN), DEN + Mel, DEN + MSCs, DEN + MSCs preconditioned with Mel, and DEN + MSCs + Mel. The obtained data revealed that administration of Mel before MSCs treatment without preconditioning yielded a better ameliorative effect against DEN-induced hepatocellular carcinoma (HCC) as evidenced by: 1) reduced serum levels of alpha fetoprotein and gamma-glutamyl transferase; 2) decreased number and area of glutathione S-transferase placental positive foci; 3) induced apoptosis (as indicated by increased cleaved caspase-3 activity, upregulated expression of proapoptotic genes Bax and caspase 3 and downregulated expression of anti-apoptotic genes Bcl2, survivin); 4) decreased malondialdehyde level and increased activities of superoxide dismutase, catalase, and glutathione peroxidase enzymes; and 5) reduced inflammation, angiogenesis and metastasis as indicated by downregulated expression of interleukin 1 beta, nuclear factor kappa B, vascular endothelial growth factor, and matrix metallopeptidase 9 genes and upregulated expression of metalloproteinase inhibitor 1 gene. Thus, administration of Mel before MSCs (without preconditioning) fostered the survival and therapeutic potential of MSCs in HCC, possibly through induction of apoptosis and inhibition of inflammation and oxidative stress. This new strategy showed better therapeutic outcomes and may improve MSC-based therapies for HCC.

Melatonin plays critical role in mesenchymal stem cell-based regenerative medicine in vitro and in vivo

Although stem cells have emerged as promising sources for regenerative medicine, there are many potential safety hazards for their clinical application, including tumorigenicity, an availability shortage, senescence, and sensitivity to toxic environments. Mesenchymal stem cells (MSCs) have various advantages compared to other stem cells, including embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs); thus, MSCs have been intensely investigated in recent studies. However, they are placed in a harsh environment after isolation and transplantation, and the adverse microenvironment substantially reduces the viability and therapeutic effects of MSCs. Intriguingly, melatonin (MT), which is primarily secreted by the pineal organ, has been found to influence the fate of MSCs during various physiological and pathological processes. In this review, we will focus on the recent progress made regarding the influence of MT on stem cell biology and its implications for regenerative medicine. In addition, several biomaterials have been proven to significantly improve the protective effects of MT on MSCs by controlling the release of MT. Collectively, MT will be a promising agent for enhancing MSC activities and the regenerative capacity via the regulation of reactive oxygen species (ROS) generation and the release of immune factors in regenerative medicine.

Melatonin protects chronic kidney disease mesenchymal stem cells against senescence via PrPC -dependent enhancement of the mitochondrial function

Although mesenchymal stem cell (MSC)-based therapy is a treatment strategy for ischemic diseases associated with chronic kidney disease (CKD), MSCs of CKD patients undergo accelerated senescence, with decreased viability and proliferation upon uremic toxin exposure, inhibiting their utility as a potent stem cell source for transplantation therapy. We investigated the effects of melatonin administration in protecting against cell senescence and decreased viability induced by pathophysiological conditions near the engraftment site. MSCs harvested from CKD mouse models were treated with H₂ O₂ to induce oxidative stress. CKD-derived MSCs exhibited greater oxidative stress-induced senescence than normal-mMSCs, while melatonin protected CKD-mMSCs from H₂ O₂ and associated excessive senescence. The latter was mediated by PrP^C -dependent mitochondrial functional enhancement; melatonin upregulated PrP^C , which bound PINK1, thus promoting mitochondrial dynamics and metabolism. In vivo, melatonin-treated CKD-mMSCs survived longer, with increased secretion of angiogenic cytokines in ischemic disease engraftment sites. CKD-mMSCs are more susceptible to H₂ O₂ -induced senescence than normal-mMSCs, and melatonin administration protects CKD-mMSCs from excessive senescence by upregulating PrP^C and enhancing mitochondrial function. Melatonin showed favorable therapeutic effects by successfully protecting CKD-mMSCs from related ischemic conditions, thereby enhancing angiogenesis and survival. These results elucidate the mechanism underlying senescence inhibition by melatonin in stem cell-based therapies using mouse-derived CKD-mMSCs.

Enhancement of the efficacy of mesenchymal stem cells in the treatment of ischemic diseases

Ischemic diseases refer to a wide range of diseases caused by reduced blood flow and a subsequently deficient oxygen and nutrient supply. The pathogenesis of ischemia is multifaceted and primarily involves inflammation, oxidative stress and an apoptotic response. Over the last decade, mesenchymal stem cells (MSCs) have been widely studied as potential cell therapy agents for ischemic diseases due to their multiple favourable functions. However, the low homing and survival rates of transplanted cells have been concerns limiting for their clinical application. Recently, increasing studies have attempted to enhance the efficacy of MSCs by various strategies including genetic modification, pretreatment, combined application and biomaterial application. The purpose of this review is to summarize these creative strategies and the progress in basic and preclinical studies.

Melatonin protects mesenchymal stem cells from autophagy-mediated death under ischaemic ER-stress conditions by increasing prion protein expression

Object

The purpose of this study was to explore whether melatonin could protect mesenchymal stem cells (MSCs) against ischaemic injury, by inhibiting endoplasmic reticulum (ER) stress and autophagy both in vivo and in vitro.

Materials and Methods

To confirm the protective effect of melatonin against ER stress in MSCs, markers of cell viability, apoptosis and autophagy were analysed. To further investigate the regenerative effect of melatonin‐treated MSCs in ischaemic tissues, a murine hindlimb ischaemic model was established.

Results

Under oxidative stress conditions, treatment with melatonin suppressed the activation of ER stress–associated proteins and autophagy‐associated proteins acting through upregulation of cellular prion protein (PrP^C) expression. Consequently, inhibition of apoptotic cell death occurred. Melatonin also promoted the activation of MnSOD and catalase activities in MSCs. In a murine hindlimb ischaemia model, melatonin‐treated MSCs also enhanced the functional limb recovery as well as neovascularization. These beneficial effects of melatonin were all blocked by knock‐down of PrP^C expression.

Conclusion

Melatonin protects against ER stress/autophagy‐induced apoptotic cell death by augmenting PrP^C expression. Thus, melatonin‐treated MSCs could be a potential cell‐based therapeutic agent for ER stress–induced ischaemic diseases, and melatonin‐induced PrP^C might be a key molecule in ameliorating ER stress and autophagy.

Daily melatonin protects the endothelial lineage and functional integrity against the aging process, oxidative stress, and toxic environment and restores blood flow in critical limb ischemia area in mice

We tested the hypothesis that daily melatonin treatment protects endothelial lineage and functional integrity against the aging process, oxidative stress/endothelial denudation (ED), and toxic environment and restored blood flow in murine critical limb ischemia (CLI). In vitro study using HUVECs, in vivo models (ie, CLI through left femoral artery ligation and ED through carotid artery wire injury), and model of lipopolysaccharide-induced aortic injury in young (3 months old) and aged (8 months old) mice were used to elucidate effects of melatonin treatment on vascular endothelial integrity. In vitro study showed that menadione-induced oxidative stress (NOX-1/NOX-2), inflammation (TNF-α/NF-kB), apoptosis (cleaved caspase-3/PARP), and mitochondrial damage (cytosolic cytochrome c) in HUVECs were suppressed by melatonin but reversed by SIRT3-siRNA (all P < .001). In vivo, reduced numbers of circulating endothelial progenitor cells (EPCs) (C-kit/CD31+/Sca-1/KDR+/CXCR4/CD34+), and angiogenesis (Matrigel assay of bone marrow-derived EPC and ex vivo aortic ring cultures) in older (compared with younger) mice were significantly reversed through daily melatonin administration (20 mg/kg/d, ip) (all P < .001). Aortic vasorelaxation and nitric oxide release were impaired in older mice and reversed in age-match mice receiving melatonin (all P < .01). ED-induced intimal/medial hyperplasia, reduced blood flow to ischemic limb, and angiogenesis (reduced CD31+/vWF+ cells/small vessel number) were improved after daily melatonin treatment (all P < .0001). Lipopolysaccharide-induced aortic endothelial cell detachment, which was more severe in aged mice, was also alleviated after daily melatonin treatment (P < .0001). Daily melatonin treatment protected both structural and functional integrity of vascular endothelium against aging-, oxidative stress-, lipopolysaccharide-, and ischemia-induced damage probably through upregulating the SIRT signaling pathway.

Melatonin and its metabolites vs oxidative stress: From individual actions to collective protection

Oxidative stress (OS) represents a threat to the chemical integrity of biomolecules including lipids, proteins, and DNA. The associated molecular damage frequently results in serious health issues, which justifies our concern about this phenomenon. In addition to enzymatic defense mechanisms, there are compounds (usually referred to as antioxidants) that offer chemical protection against oxidative events. Among them, melatonin and its metabolites constitute a particularly efficient chemical family. They offer protection against OS as individual chemical entities through a wide variety of mechanisms including electron transfer, hydrogen transfer, radical adduct formation, and metal chelation, and by repairing biological targets. In fact, many of them including melatonin can be classified as multipurpose antioxidants. However, what seems to be unique to the melatonin's family is their collective effects. Because the members of this family are metabolically related, most of them are expected to be present in living organisms wherever melatonin is produced. Therefore, the protection exerted by melatonin against OS may be viewed as a result of the combined antioxidant effects of the parent molecule and its metabolites. Melatonin's family is rather exceptional in this regard, offering versatile and collective antioxidant protection against OS. It certainly seems that melatonin is one of the best nature's defenses against oxidative damage.

BM‑MSCs protect against liver ischemia/reperfusion injury via HO‑1 mediated autophagy

Ischemia/reperfusion (I/R) injury is considered to be a contributing factor in liver injury following major hepatic resection or liver transplantation. Bone marrow mesenchymal stem cells (BM‑MSCs) have the potential to protect against liver I/R injury; however, the precise mechanisms have not been completely elucidated. Autophagy serves an important role in protecting against various injuries, including I/R injury. The present study aimed to determine the role of autophagy and its potential regulatory mechanism in BM‑MSC‑mediated protection against liver I/R injury in rats. The results demonstrated that BM‑MSCs mitigated I/R injury and enhanced autophagy in vivo. In addition, inhibition of autophagy by 3‑methyladenine reversed the positive effects of BM‑MSCs. Furthermore, heme oxygenase‑1 (HO‑1) expression was promoted by BM‑MSCs. Using zinc protoporphyrin IX to inhibit HO‑1 demonstrated that HO‑1 was important for the promotion of autophagy. In conclusion, the present study revealed that BM‑MSCs protected against liver I/R injury via the promotion of HO‑1‑mediated autophagy.

Functional Interaction between Melatonin Signaling and Noncoding RNAs

Melatonin was discovered in the pineal gland and first came to be known as a biochemical synchronizer of circadian rhythm. The molecular mechanisms underlying the broad-spectrum actions of melatonin are not restricted to its interaction with proteins but it also has functional effects after influencing RNA species that have no protein-coding potential. In this review we discuss the current understanding of the melatonin-mediated modulation of noncoding RNA (ncRNA) pathways under different physiological and pathological conditions. We also delineate the impact of specific ncRNAs in controlling the synthesis of melatonin. The information compiled herein will serve as a solid foundation to formulate ideas for future mechanistic studies on melatonin and to better explore the emerging functions of the noncoding transcriptome.

Xenogeneic human umbilical cord-derived mesenchymal stem cells reduce mortality in rats with acute respiratory distress syndrome complicated by sepsis

This study tested the hypothesis that xenogeneic human umbilical cord-derived mesenchymal stem cell (HUCDMSC) therapy would improve survival rates in rats with acute respiratory distress-syndrome (ARDS, induction by 48 h inhalation of 100% oxygen) and sepsis-syndrome (SS, induction by cecal-ligation and puncture) (ARDS-SS). Adult-male Sprague-Dawley rats were categorized into group 1 (sham-controls), group 2 (ARDS-SS), group 3 [ARDS-SS+HUCDMSC (1.2 ×106 cells administered 1 h after SS-induction)], and group 4 [ARDS-SS+HUCDMSC (1.2 ×106 cells administered 24 h after SS-induction)]. The mortality rate was higher in groups 2 and 4 than in groups 1 and 3 (all p<0.0001). The blood pressure after 28 h was lower in groups 2, 3 and 4 (p<0.0001) than in group 1. Albumin levels and percentages of inflammatory cells in broncho-alveolar lavage fluid, and the percentages of inflammatory and immune cells in circulation, were lowest in group 1, highest in group 2, and higher in group 3 than group 4 (all p<0.0001). The percentages of inflammatory cells in ascites and kidney parenchyma showed identical patterns, as did kidney injury scores (all p<0.0001). EarlyHUCDMSC therapy reduced rodent mortality after induced ARDS-SS.

Dose-dependent proliferative and cytotoxic effects of melatonin on human epidermoid carcinoma and normal skin fibroblast cells

New in vitro studies have demonstrated that N-acetyl-5-methoxytryptamine (Melatonin) has cytotoxic and apoptotic effects on various cell types although most of the previous investigations document that it is a potent antioxidant. However, the precise molecular mechanism(s) of its effects are not fully elucidated. In this study, we examined dose-dependent cytotoxic, genotoxic, apoptotic and reactive oxygen species (ROS) generating effects of melatonin in human epidermoid carcinoma cells (A-431) and human normal skin fibroblastic cells (CCD-1079Sk). The cells were incubated with different doses of melatonin (0.031-5 mM) for 24 h. Cell viability was assessed based on luminometric ATP cell viability assay. Intracellular ROS was detected using 2,7-dichlorodihydrofluorescein-diacetate (H₂DCF-DA) fluorescent probes. Genotoxicity was evaluated by alkaline single cell gel electrophoresis assay (Comet Assay). Apoptosis was evaluated by western blotting, DAPI staining, acridine orange/ethidium bromide and Annexin V-FITC/propidium iodide double staining methods Mitochondrial membrane potentials were measured by flow cytometry. Although lower doses of melatonin (0.031-0.06 mM) increased cell proliferation and decreased ROS generation, higher doses (0.125-5 mM) markedly inhibited the cell viability, induced DNA damage, apoptosis and ROS generation. Cytotoxic, genotoxic, apoptotic and ROS generating effects were significantly higher in cancer cells than those observed in normal cells. Melatonin-induced cell death, and ROS generating activity were effectively inhibited by N-acetyl-l-cysteine (NAC) In conclusion, at low doses, melatonin has proliferative effects on both cancer and normal cells, whereas high concentrations have cytotoxic effects. Cytotoxic, genotoxic and apoptotic effects at higher doses of melatonin may be due to its ROS production capacity.

Combined Therapy with Extracorporeal Shock Wave and Adipose-Derived Mesenchymal Stem Cells Remarkably Improved Acute Ischemia-Reperfusion Injury of Quadriceps Muscle

Extracorporeal shock wave (ECSW) and adipose-derived mesenchymal stem cells (ADMSCs) have been recognized to have capacities of anti-inflammation and angiogenesis. We tested the hypothesis that ECSW and ADMSC therapy could attenuate ischemia-reperfusion- (IR-) induced thigh injury (femoral artery tightened for 6 h then the tightness was relieved) in rats. Adult male SD rats (n = 30) were divided into group 1 (sham-control), group 2 (IR), group 3 (IR + ECSW/120 impulses at 0.12 mJ/mm² given at 3 h/24 h/72 h after IR), group 4 (allogenic ADMSC/1.2 × 10⁶ cell intramuscular and 1.2 × 10⁶ cell intravenous injections 3 h after IR procedure), and group 5 (ECSW + ADMSC). At day 7 after the IR procedure, the left quadriceps muscle was harvested for studies. At 18 h after the IR procedure, serum myoglobin/creatine phosphokinase (CPK) levels were highest in group 2, lowest in group 1, and with intermediate values significantly progressively reduced in groups 3 to 5 (all p < 0.0001). By day 5 after IR, the mechanical paw-withdrawal threshold displayed an opposite pattern of CPK (all p < 0.0001). The protein expressions of inflammatory, oxidative-stress, apoptotic, fibrotic, DNA-damaged, and mitochondrial-damaged biomarkers and cellular expressions of inflammatory and DNA-damaged biomarkers exhibited an identical pattern of CPK among the five groups (all p < 0.0001). The microscopic findings of endothelial-cell biomarkers and number of arterioles expressed an opposite pattern of CPK, and the angiogenesis marker was significantly progressively increased from groups 1 to 5, whereas the histopathology showed that muscle-damaged/fibrosis/collagen-deposition areas exhibited an identical pattern of CPK among the five groups (all p < 0.0001). In conclusion, ECSW-ADMSC therapy is superior to either one applied individually for protecting against IR-induced thigh injury.

Melatonin alleviates weanling stress in mice: Involvement of intestinal microbiota

Melatonin influences intestinal microbiota and the pathogenesis of various diseases. This study was conducted to explore whether melatonin alleviates weanling stress through intestinal microbiota in a weanling mouse model. Melatonin supplementation in weanling mice (provided in the drinking water at a dosage of 0.2 mg/mL for 2 weeks) significantly improved body weight gain (1.4 ± 0.03 g/day in melatonin group vs 1.2 ± 0.06 g/day in control group) and intestinal morphology (ie, villus length, crypt depth, and villus to crypt ratio), but had little effect on the proliferation or apoptosis of intestinal cells, the numbers of Paneth cells and goblet cells, as well as the expression of makers related to enterocytes (sucrase) and endocrine cells (chromogranin A and peptide YY) in the ileum. Melatonin supplementation had little effect on serum levels of amino acids or stress-related parameters (eg, SOD, TNF-α, and angiotensin I). 16S rRNA sequencing suggested that melatonin supplementation increased the richness indices of intestinal microbiota (observed species, Chao 1, and ACE) and shaped the composition of intestinal microbiota (eg, increase in the abundance of Lactobacillus [19 ± 3% in melatonin group vs 6 ± 2% in control group]), which was demonstrated using an ex vivo proliferation assay and colonic loop proliferation assay. Melatonin supplementation also significantly influenced the metabolism of intestinal microbiota, such as amino acid metabolism and drug metabolism. More importantly, in antibiotic-treated weanling mice and germ-free weanling mice, melatonin failed to affect body weight gain or intestinal morphology. Melatonin significantly reduced (by about 60%) the bacterial load in enterotoxigenic Escherichia coli (ETEC)-infected weanling mice, but had little effect on ETEC load in antibiotic-pretreated animals. In conclusion, melatonin affects body weight gain, intestinal morphology, and intestinal ETEC infection through intestinal microbiota in weanling mice. The findings highlight the importance of intestinal microbiota in mediating the various physiological functions of melatonin in the host.

Pineal Calcification, Melatonin Production, Aging, Associated Health Consequences and Rejuvenation of the Pineal Gland

The pineal gland is a unique organ that synthesizes melatonin as the signaling molecule of natural photoperiodic environment and as a potent neuronal protective antioxidant. An intact and functional pineal gland is necessary for preserving optimal human health. Unfortunately, this gland has the highest calcification rate among all organs and tissues of the human body. Pineal calcification jeopardizes melatonin's synthetic capacity and is associated with a variety of neuronal diseases. In the current review, we summarized the potential mechanisms of how this process may occur under pathological conditions or during aging. We hypothesized that pineal calcification is an active process and resembles in some respects of bone formation. The mesenchymal stem cells and melatonin participate in this process. Finally, we suggest that preservation of pineal health can be achieved by retarding its premature calcification or even rejuvenating the calcified gland.

Human Adipose Stromal Cells Increase Survival and Mesenteric Perfusion Following Intestinal Ischemia and Reperfusion Injury

OBJECTIVE

Intestinal ischemia can quickly escalate to bowel necrosis and perforation. Transplantation of stem cells presents a novel treatment modality for this problem. We hypothesized that: human adipose-derived stromal cells (hASCs) would increase survival and mesenteric perfusion to a greater degree compared with differentiated cellular controls following ischemic intestinal injury, and improved outcomes with hASC therapy would be associated with preservation of intestinal histological and tight junction architecture, and lower levels of systemic inflammation following intestinal injury.

METHODS

hASCs and keratinocytes (differentiated cellular control) were cultured on polystyrene flasks at 37°C in 5% CO2 in air. Adult male C57Bl6J mice were anesthetized and a midline laparotomy performed. The intestines were eviscerated, the small bowel mesenteric root identified, and intestinal ischemia was established by temporarily occluding the superior mesenteric artery for 60 min with a noncrushing vascular clamp. Following ischemia, the clamp was removed, and the intestines were returned to the abdominal cavity. Before abdominal closure, 2 million hASCs or keratinocytes in 250 μL of phosphate-buffered saline (carrier for cells and control solution) were infused into the peritoneum. Animals were allowed to recover for 12 or 24 h (perfusion, histology, cytokine, and immunofluoresence studies), or 7 days (survival studies). Intestinal perfusion was assessed by laser Doppler imaging. Intestinal tissue segments were stained with hematoxylin and eosin, as well as antibodies for the tight junction protein claudin-1. Separate aliquots of intestine, liver, and lung tissue were homogenized and assessed for inflammatory cytokines via multiplex beaded assay.

RESULTS

Animals administered hASCs following intestinal ischemia and reperfusion (I/R) injury had significantly greater 7-day survival and better postischemic recovery of mesenteric perfusion compared with vehicle or keratinocyte therapy. hASCs also abated intestinal mucosal destruction, facilitated preservation of intestinal tight junctions, and decreased the systemic inflammatory response to injury.

CONCLUSIONS

Human adipose-derived stromal cells improved survival and mesenteric perfusion and attenuated the mucosal damage associated with intestinal I/R injury. hASCs should be considered as a plausible cell source for novel cellular treatment plans following intestinal ischemia.

Melatonin attenuated brain death tissue extract-induced cardiac damage by suppressing DAMP signaling

We tested the hypothesis that melatonin prevents brain death (BD) tissue extract (BDEX)-induced cardiac damage by suppressing inflammatory damage-associated molecular pattern (DAMP) signaling in rats. Six hours after BD induction, levels of a DAMP component (HMGB1) and inflammatory markers (TLR-2, TLR-4, MYD88, IκB, NF-κB, IL-1β, IFN-γ, TNF-α and IL-6) were higher in brain tissue from BD animals than controls. Levels of HMGB1 and inflammatory markers were higher in BDEX-treated H9C2 cardiac myoblasts than in cells treated with healthy brain tissue extract. These increases were attenuated by melatonin but re-induced with luzindole (all P < 0.001). Additional male rats (n = 30) were divided into groups 1 (negative control), 2 (healthy brain tissue extract implanted in the left ventricular myocardium [LVM]), 3 (BDEX-LVM), 4 (BDEX-LVM + melatonin), and 5 (BDEX-LVM + melatonin + luzindole). Collagen deposition/fibrosis and LVM levels of MTR2, HMGB1, inflammatory markers, oxidative stress, apoptosis, mitochondrial damage and DNA damage were highest in group 3, lowest in groups 1 and 2, and higher in group 5 than in group 4. Heart function and LVM levels of MTR1 and anti-inflammatory, mitochondrial-integrity and anti-oxidative markers exhibited a pattern opposite that of the inflammatory markers in the five groups (all P < 0.0001). These results indicate melatonin inhibits BDEX-induced cardiac damage by suppressing the DAMP inflammatory axis.

Melatonin and mitochondrial function during ischemia/reperfusion injury

Ischemia/reperfusion (IR) injury occurs in many organs and tissues, and contributes to morbidity and mortality worldwide. Melatonin, an endogenously produced indolamine, provides a strong defense against IR injury. Mitochondrion, an organelle for ATP production and a decider for cell fate, has been validated to be a crucial target for melatonin to exert its protection against IR injury. In this review, we first clarify the mechanisms underlying mitochondrial dysfunction during IR and melatonin's protection of mitochondria under this condition. Thereafter, special focus is placed on the protective actions of melatonin against IR injury in brain, heart, liver, and others. Finally, we explore several potential future directions of research in this area. Collectively, the information compiled here will serve as a comprehensive reference for the actions of melatonin in IR injury identified to date and will hopefully aid in the design of future research and increase the potential of melatonin as a therapeutic agent.

Therapeutic effects of adipose-derived mesenchymal stem cells against brain death-induced remote organ damage and post-heart transplant acute rejection

We tested the hypothesis that allogenic adipose-derived mesenchymal stem cells (ADMSCs) alleviated brain death (BD)-induced remote organ damage and events of post heart-transplant acute rejection. To determine the impact of BD on remote organ damage, adult-male F344 rats (n=24) were categorized sham-control (SC), BD and BD^MSC (allogenic ADMSC/1.2 × 10⁶ cells/derived from F344 by intravenous transfusion 3 h after BD procedure). To determine the protective effect of allogenic ADMSCs, animals (n=8/each group in F344/Lewis) were categorized into groups BD-T(F344 heart transplanted into Lewis by 6h after BD), BD-T^MSC(D1/3) (BD induction for 6h then heart transplantation, and allogenic ADMSCs transfusion at days 1 and 5 after heart transplantation), BD-T^MSC(3h) (BD + ADMSC/1.2 × 10⁶ cells at 3h and heart transplantation at 6h after BD) and BD-T^{MSC(3h, D1/3)} [BD + ADMSC/1.2 × 10⁶ cells at 3h and heart transplantation at 6h after BD, then ADMSC therapy by days 1/3]. At day 5 post procedure, liver, kidney and heart specimens showed higher molecular-cellular levels of inflammation, immune reaction, apoptosis and fibrosis in BD than in SC that were reversed in BD^MSC (all P < 0.0001). These molecular-cellular expressions and circulating/splenic levels of innate/adoptive immune cells were higher in BD-T, lowest in BD-T^{MSC(3h, D1/3)} and higher BD-T^MSC(3h) in than BD-T^MSC(D1/3), whereas heart function showed an opposite pattern among the four groups (all P < 0.001). In conclusion, ADMSCs suppressed BD-caused remote organ damage and heart-transplant rejection.

DPP-4 enzyme deficiency protects kidney from acute ischemia-reperfusion injury: role for remote intermittent bowel ischemia-reperfusion preconditioning

We analyzed the effects of acute ischemia-reperfusion (KIR) injury on the status of kidney function and architecture in dipeptidyl peptidase4-difficient (DPP4^D) rats and the effect of remote small bowel ischemia-reperfusion (BIR) preconditioning. DPP4-deficient (DPP4^D) and normal Fischer344 (F344) rats were divided into 6 groups: (1) sham-F344, (2) sham-DPP4^D, (3) KIR-F344 (4) KIR-DPP4^D, (5) DPP4^D-KIR-extendin-9-39 and (6) BIR-KIR-F344. Blood creatinine and urea nitrogen levels and the urinary protein-to-creatinine ratio was higher in KIR-F344 rats than BIR-KIR-F344 or KIR-DPP4^D rats 72 h after acute KIR. Conversely, the circulating glucagon-like peptide 1 (GLP-1) levels were higher in BIR-KIR-F344 and KIR-DPP4^D than KIR-F344 rats after acute KIR. KIR-F344 rats showed greater inflammation, oxidative stress, apoptosis, DNA damage and kidney injury than other rat groups. Damage to the kidney architecture in KIR-F344 rats was greater than in BIR-KIR-F344 or KIR-DPP4^D rats. Expression of antioxidant proteins and GLP-1 receptor was higher in kidneys from KIR-DPP4^D and BIR-KIR-F344 than KIR-F344 rats, which suggests better intrinsic responses. We therefore suggest that elevated circulating GLP-1 levels due to DPP4 deficiency and BIR preconditioning protect kidney function and architecture during acute IR injury.

Mechanism of salutary effects of melatonin-mediated liver protection after trauma-hemorrhage: p38 MAPK-dependent iNOS/HIF-1α pathway

Although melatonin attenuates the increases in inflammatory mediators and reduces organ injury during trauma-hemorrhage, the mechanisms remain unclear. This study explored whether melatonin prevents liver injury after trauma-hemorrhage through the p38 mitogen-activated protein kinase (MAPK)-dependent, inducible nitrite oxide (iNOS)/hypoxia-inducible factor (HIF)-1α pathway. After a 5-cm midline laparotomy, male rats underwent hemorrhagic shock (mean blood pressure ~40 mmHg for 90 min) followed by fluid resuscitation. At the onset of resuscitation, rats were treated with vehicle, melatonin (2 mg/kg), melatonin plus p38 MAPK inhibitor SB203580 (2 mg/kg), or melatonin plus the melatonin receptor antagonist luzindole (2.5 mg/kg). At 2 h after trauma-hemorrhage, histopathology score of liver injury, liver tissue myeloperoxidase activity, malondialdehyde, adenosine triphosphate, serum alanine aminotransferase, and asparate aminotransferase levels were significantly increased compared with sham-operated control. Trauma-hemorrhage resulted in a significant decrease in the p38 MAPK activation compared with that in the sham-treated animals. Administration of melatonin after trauma-hemorrhage normalized liver p38 MAPK phosphorylation and iNOS and HIF-1α expression and attenuated cleaved caspase 3 and receptor interacting protein kinase-1 levels. Coadministration of SB203580 or luzindole abolished the melatonin-mediated attenuation of the trauma-hemorrhage-induced increase of iNOS/HIF-1α protein expression and liver injury markers. Taken together, our results suggest that melatonin prevents trauma-hemorrhage-induced liver injury in rats, at least in part, through melatonin receptor-related, p38 MAPK-dependent iNOS/HIF-1α pathway.NEW & NOTEWORTHY Trauma-hemorrhage resulted in a significant decrease in liver p38 MAPK activation and increase in nitrite oxide synthase (iNOS) and hypoxia-inducible factor (HIF)-1α expression. Administration of melatonin after trauma-hemorrhage normalized liver p38 MAPK phosphorylation and iNOS and HIF-1α expression, which was abolished by coadministration of SB203580 or luzindole. Melatonin prevents trauma-hemorrhage-induced liver injury in rats via the melatonin receptor-related, p38 MAPK-dependent iNOS/HIF-1α pathway.