Immune regulatory properties of multipotent mesenchymal stromal cells:Where do we stand?

Multipotent mesenchymal stromal cells (MSC) can be isolated and efficiently expanded from almost every single body tissue and have the ability of self-renewal and differentiation into various mesodermal cell lineages. Moreover, these cells are considered immunologically privileged, related to a lack of surface expression of costimulatory molecules required for complete T cell activation. Recently, it has been observed that MSC are capable of suppressing the immune response by inhibiting the maturation of dendritic cells and suppressing the function of T lymphocytes, B lymphocytes and natural killer cells in autoimmune and inflammatory diseases as a new strategy for immunosuppression. The understanding of immune regulation mechanisms by MSC is necessary for their use as immunotherapy in clinical applications for several diseases.

Cytoprotective role of heme oxygenase-1 and heme degradation derived end products in liver injury

The activation of heme oxygenase-1(HO-1) appears to be an endogenous defensive mechanism used by cells to reduce inflammation and tissue damage in a number of injury models. HO-1, a stress-responsive enzyme that catabolizes heme into carbon monoxide(CO), biliverdin and iron, has previously been shown to protect grafts from ischemia/reperfusion and rejection.In addition, the products of the HO-catalyzed reaction, particularly CO and biliverdin/bilirubin, have been shown to exert protective effects in the liver against a number of stimuli, as in chronic hepatitis C and in transplanted liver grafts. Furthermore, the induction of HO-1 expression can protect the liver against damage caused by a number of chemical compounds. More specifically, the CO derived from HO-1-mediated heme catabolism has been shown to be involved in the regulation of inflammation; furthermore, administration of low concentrations of exogenous CO has a protective effect against inflammation. Both murine and human HO-1 deficiencies have systemic manifestations associated with iron metabolism, such as hepatic overload(with signs of a chronic hepatitis) and iron deficiency anemia(with paradoxical increased levels of ferritin).Hypoxia induces HO-1 expression in multiple rodent,bovine and monkey cell lines, but interestingly, hypoxia represses expression of the human HO-1 gene in a variety of human cell types(endothelial cells, epithelial cells, T cells). These data suggest that HO-1 and CO are promising novel therapeutic molecules for patients with inflammatory diseases. In this review, we present what is currently known regarding the role of HO-1 in liver injuries and in particular, we focus on the implications of targeted induction of HO-1 as a potential therapeutic strategy to protect the liver against chemically induced injury.

Use of pre-, pro- and synbiotics in patients with acute pancreatitis:A meta-analysis

AIM: To assess the clinical outcomes of pre-, pro-and synbiotics therapy in patients with acute pancreatitis. METHODS: The databases including Medline, Embase, the Cochrane Library, Web of Science and Chinese Biomedicine Database were searched for all relevant randomized controlled trials that studied the effects of pre-, pro- or synbiotics in patients with acute pancreatitis. Main outcome measures were postoperative infections, pancreatic infections, multiple organ failure (MOF), systemic inflammatory response syndrome (SIRS), length of hospital stay, antibiotic therapy and mortality. RESULTS: Seven randomized studies with 559 acute pancreatic patients were included. Pre-, pro-or synbiot-ics treatment showed no influence on the incidence of postoperative infections [odds ratios (OR) 0.30, 95% conf idence interval (CI): 0.09-1.02, P = 0.05], pancre- atic infection (OR 0.50, 95% CI: 0.12-2.17, P = 0.36), MOF (OR 0.88, 95% CI: 0.35-2.21, P = 0.79) and SIRS (OR 0.78, 95% CI: 0.20-2.98, P = 0.71). There were also no signif icant differences in the length of antibiotic therapy (OR 0.75, 95% CI: 0.50-1.14, P = 0.18) and the mortality (OR 0.75, 95% CI: 0.25-2.24, P = 0.61). However, Pre-, pro-or synbiotics treatment was associ- ated with a reduced length of hospital stay (OR -3.87, 95% CI: -6.20 to -1.54, P = 0.001). When stratifying for the severity of acute pancreatitis, the main results were similar. CONCLUSION: Pre-, pro-or synbiotics treatment shows no significant influence on patients with acute pancreatitis. There is a lack of evidence to support the use of probiotics/synbiotics in this area.

Treatment of chronic proliferative cholangitis with c-myc shRNA

AIM: To investigate the feasibility and effectiveness of c-myc shRNA in inhibiting the hyperplastic behavior and lithogenic potentiality of chronic proliferative cholangitis (CPC), in order to prevent stone recurrence and biliary restenosis.METHODS: An animal model of CPC was established by giving intralumenally 0.5 mL of c-myc shRNA. Then, the effects of c-myc shRNA on hyperplastic behavior and lithogenic potentiality of CPC were evaluated by histological observation, immunohistochemistry, real-time PCR and Western blotting for c-myc, proliferating cell nuclear antigen (PCNA), procollagen TM mucin5AC, enzymatic histochemistry for β-glucuronidase, and biochemistry for hydroxyproline in the diseased bile duct.RESULTS: Treatment with c-myc shRNA efficiently suppressed the hyperplasia of biliary epithelium, submucosal gland, and collagen fiber by inhibiting mRNA and protein expression of c-myc. More importantly, it decreased the lithogenic potentiality of CPC by inhibiting the expression of mucin 5AC and the secretion of endogenous β-glucuronidase. Further investigation indicated that c-myc shRNA-3 had a better inhibitory effect on CPC.CONCLUSION: Treatment with c-myc shRNA-3 can control CPC and reduce the lithogenic potentiality of CPC.

Human leukocyte antigen compatibility and incidence of donorspecific antibodies in pediatric liver transplant recipients

BACKGROUND Antibody-mediated rejection following liver transplantation(LT)has been increasingly recognized,particularly with respect to the emergence of de novo donor-specific antibodies(DSAs)and their impact on graft longevity.While substantial evidence for adult populations exists,research focusing on pediatric LT outcomes remains limited.AIM To investigate the prevalence of human leukocyte antigen(HLA)mismatches and DSA and evaluate their association with rejection episodes after pediatric LT.METHODS A cohort of pediatric LT recipients underwent HLA testing at Santa Casa de Porto Alegre,Brazil,between December 2013 and December 2023.Only patients who survived for>30 days after LT with at least one DSA analysis were included.DSA classes I and II and cross-matches were analyzed.The presence of de novo DSA(dnDSA)was evaluated at least 3 months after LT using the Luminex®single antigen bead method,with a positive reaction threshold set at 1000 MFI.Rejection episodes were confirmed by liver biopsy.RESULTS Overall,67 transplanted children were analyzed;61 received grafts from living donors,85%of whom were related to recipients.Pre-transplant DSA(class I or II)was detected in 28.3%of patients,and dnDSA was detected in 48.4%.The median time to DSA detection after LT was 19.7[interquartile range(IQR):4.3-35.6]months.Biopsyproven rejection occurred in 13 patients at follow-up,with C4d positivity observed in 5/13 Liver biopsies.The median time to rejection was 7.8(IQR:5.7-12.8)months.The presence of dnDSA was significantly associated with rejection(36%vs 3%,P<0.001).The rejection-free survival rates at 12 and 24 months were 76%vs 100%and 58%vs 95%for patients with dnDSA anti-DQ vs those without,respectively.CONCLUSION Our findings highlight the importance of incorporating DSA assessment into pre-and post-transplantation protocols for pediatric LT recipients.Future implications may include immunosuppression minimization strategies based on this analysis in pediatric LT recipients.

Innate lymphoid cells in tissue homeostasis and diseases

Innate lymphoid cells(ILCs) are the most recently discovered family of innate immune cells. They are a part of the innate immune system, but develop from the lymphoid lineage. They lack pattern-recognition receptors and rearranged receptors, and therefore cannot directly mediate antigen specific responses. The progenitors specifically associated with the ILCs lineage have been uncovered, enabling the distinction between ILCs and natural killer cells. Based on the requirement of specific transcription factors and their patterns of cytokine production, ILCs are categorized into three subsets(ILC1, ILC2 and ILC3). First observed in mucosal surfaces, these cell populations interact with hematopoietic and non-hematopoietic cells throughout the body during homeostasis and diseases, promoting immunity, commensal microbiota tolerance, tissue repair and inflammation. Over the last 8 years, ILCs came into the spotlight as an essential cell type able to integrate diverse host immune responses. Recently, it became known that ILC subsets play a key role in immune responses at barrier surfaces, interacting with the microbiota, nutrients and metabolites. Since the liver receives the venous blood directly from the intestinal vein, the intestine and liver are essential to maintain tolerance and can rapidly respond to infections or tissue damage. Therefore, in this review, we discuss recent findings regarding ILC functions in homeostasis and disease, with a focus on the intestine and liver.

Prostate-specific antigen screening for prostate cancer： benefits for patients with highly aggressive prostate cancer

The US Preventive Services Task Force （USPSTF） analyzed the benefits and harms of prostate specific antigen （PSA）- based screening for prostate cancer （PCa）. The Grade ＇D＇ recommendation of the USPSTF was based mainly on the Prostate, Lung, Colorectal, and Ovarian （PLCO） study in the United States. That result showed only a small reduction in PCa mortality. However, the data from the International Agency for Research on Cancer （IARC） iUustrated the PCa mortality rate （MR） decreased marked. To avoid the over-diagnosis and over-treatment, the American Cancer Society has changed its strategy and updated its guidance. The USPSTF neglected the aggressive PCa accounted for more then 30% of all PCa. Highly aggressive PCa can be diagnosed by PSA screening combined with Gleason grade. We hope that the USPSTF changes the ＇D＇ recommendation for PSA screening.

Levetiracetam induces tyrosine kinase receptor B expression in SH-SY5Y cells

Tyrosine kinase receptor B （TrkB） plays an important role in long-term potentiation and memory formation.The present study used all-trans retinoic acid to induce TrkB expression in SH-SY5Y cells,and observed the effects of levetiracetam （LEV） on TrkB expression.Following exposure to 10,50,and 100 μg/mL LEV,the number of TrkB-positive cells,and average absorbance value were increased.Results demonstrated that LEV can induce TrkB expression in SH-SY5Y cells.

Monitoring of clinical islet transplantation

Islet transplantation has recently emerged as one of the most promising therapeutic approaches to improving glycometabolic control in diabetic patients. The Edmonton trials demonstrated a marked improvement in the short-term rate of success of islet transplantation, with an 80% rate of insulin-independence being at 1 year after transplantation, as reported by several institutions worldwide. Unfortunately, this rate consistently decreases to 10% by 5 years post-transplantation.

Inflammatory diseases modelling in zebrafish

The ingest of diets with high content of fats and carbohydrates, low or no physical exercise and a stressful routine are part of the everyday lifestyle of most people in the western world. These conditions are triggers for different diseases with complex interactions between the host genetics, the metabolism, the immune system and the microbiota, including inflammatory bowel diseases(IBD), obesity and diabetes. The incidence of these disorders is growing worldwide; therefore, new strategies for its study are needed. Nowadays, the majority of researches are in use of murine models for understand the genetics, physiopathology and interaction between cells and signaling pathways to find therapeutic solutions to these diseases. The zebrafish, a little tropical water fish, shares 70% of our genes and conserves anatomic and physiological characteristics, as well as metabolical pathways, with mammals, and is rising as a new complementary model for the study of metabolic and inflammatory diseases. Its high fecundity, fast development, transparency, versatility and low cost of maintenance makes the zebrafish an interesting option for new researches. In this review, we offer a discussion of the existing genetic and induced zebrafish models of two important Western diseases that have a strong inflammatory component, the IBD and the obesity.

Advances and perspectives on cellular therapy in acquired bone marrow failure diseases

Acquired bone marrow failure diseases(ABMFD) are a class of hematopoietic stem cell diseases with a commonality of non-inherited disruption of hematopoiesis that results in pancytopenia. ABMFDs also are a group of heterogeneous diseases with different etiologies and treatment options. The three most common ABMFDs are aplastic anemia, myelodysplastic syndrome, and paroxysmal nocturnal hemoglobinuria. Stem cell transplantation is the only treatment that can cure these diseases. However, due to high therapy-related mortality, stem cell transplantation has rarely been used as a first line treatment in treating ABMFD. With the advance of personalized medicine and precision medicine, various novel cellular therapy strategies are in trial to increase the efficiency and efficacy of ABMFD treatment. This article aims to review current available stem cell transplantation protocols and promising cellular therapy research in treating ABMFD.

Kinin B_2 receptor does not exert renoprotective effects on mice with glycerol-induced rhabdomyolysis

AIM:To investigate a potential protective role of the kinin B2receptor in a glycerol-induced rhabdomyolysis mouse model.METHODS:We separated 28 C57Bl/6 male mice into4 groups:untreated WT animals,untreated B2knockout mice,glycerol-treated WT and glycerol-treated B2knockout mice.Glycerol-treated animals received one intramuscular injections of glycerol solution(50%v/v,7 m L/kg).After 48 h,urine and blood samples were collected to measure creatinine and urea levels.Additionally,kidney samples were extracted for histological evaluation,and the m RNA expression levels of kinin B1 and B2 receptors and inflammatory mediators were measured by real-time polymerase chain reaction.RESULTS:Serum creatinine and urea levels showed differences between untreated wild-type and glyceroltreated wild-type mice(0.66±0.04 vs 2.61±0.53mg/d L,P<0.01;and 33.51±2.08 vs 330.2±77.7mg/d L,P<0.005),and between untreated B2knockout mice and glycerol-treated knockout mice(0.56±0.03 vs 2.23±0.87 mg/d L,P<0.05;and 42.49±3.2vs 327.2±58.4 mg/d L,P<0.01),but there was no difference between the glycerol-treated wild-type and glycerol-treated knockout mice.Glycerol was able to induce a striking increase in kinin B2receptor expression(>30 times,31.34±8.9)in kidney.Animals injected with glycerol had a higher degree of tubular injury than untreated animals.Wild-type and knockout mice treated with glycerol intramuscularly present kidney injury,with impairment in renal function.However,B2knockout mice treated with glycerol did not show a different phenotype regarding kidney injury markers,when compared to the wild-type glycerol-treated group.CONCLUSION:We conclude that the kinin B2receptordoes not have a protective role in renal injury.

Cytoprotection behind heme oxygenase-1 in renal diseases

Renal insults are considered a public health problem and are linked to increased rates of morbidity and mortality worldwide. The heme oxygenase(HO) system consists of evolutionary specialized machinery that degrades free heme and produces carbon monoxide, biliverdin and free iron. In this sense, the inducible isoform HO-1 seems to develop an important role and is widely studied. The reaction involved with the HO-1 molecule provides protection to injured tissue, directly by reducing the toxic heme molecule and indirectly by the release of its byproducts. The up regulation of HO-1 enzyme has largely been described as providing antioxidant, antiapoptotic, anti-inflammatory and immunomodulatory properties. Several works have explored the importance of HO-1 in renal diseases and they have provided consistent evidence that its overexpression has beneficial effects in such injuries. So, in this review we will focus on the role of HO-1 in kidney insults, exploring the protective effects of its up regulation and the enhanced deleterious effects of its inhibition or gene deletion.

Neuroprotective effect of exogenous vascular endothelial growth factor on rat spinal cord neurons in vitro hypoxia

Background Vascular endothelial growth factor （VEGF） is well known as a hypoxia-induced protein. That it markedly increased expression of VEGF and improvement of rat motor function after spinal cord injury suggested that VEGF could play a neuroprotective role in ischaemic tolerance. This study investigated whether vascular endothelial growth factor has direct neuroprotective effects on rat spinal cord neurons. Methods We employed primary cultures of embryonic rat spinal cord neurons, then administrated different concentrations of VEGF164 in the culture medium before hypoxia when the number of neurons was counted and the cell viability was detected by MTT. The neuronal apoptosis and expression of VEGF and its receptor genes were evaluated by terminal deoxynucleotidyl transferase mediated dUTP nick-end labelling （TUNEL） and immunohistochemistry. The VEGFR2/FLK-1 inhibitor, SU1498, was used to confirm whether the neuroprotective effect of VEGF was mediated through VEGFR2/Flk-1 receptors. Result In hypoxic conditions,the number and viability of neurons decreased progressively, while the number of TUNEL-positive cells increased along with the prolongation of hypoxic exposure. When the concentration of VEGF in cell culture medium reached 25 ng/ml, the cell viability increased 11% and neuronal apoptosis reduced to half, this effect was dose dependent and led to an approximately 25% increase in cell viability and about threefold decrease in TUNEL-positive cells at a maximally effective concentration of 100 ng/ml. In normal conditions, VEGF/Flk-1 but not VEGF/Flt-1 gene expressed at a low level： after hypoxia, the expression of VEGF/Flk-1, but not VEGF/Flt-1 was significantly increased. The protective effect of VEGF was blocked by the VEGFR2/Flk-1 receptor tyrosine kinase inhibitor, SU1498. Conclusions VEGF has direct neuroprotective effects on rat spinal cord neurons, which may be mediated in vitro through VEGFR2/Flk-1 receptors.

Indoleamine 2,3-dioxygenase and regulatory dendritic cells contribute to the allograft protection induced by infusion of donor-specific splenic stromal cells

It has been reported that splenic stromal cells(SSCs)are capable of directly supporting the development of CD11c ^(lo)CD45RB^(+) IL-10-producing dendritic cells(DCs)from lineage-negative c-kit^(+) progenitor cells in the absence of exogenous cytokines.In vitro,DCs that differentiate on stromal cells suppress mixed leukocyte reaction responses and induce primary alloreactive CD4^(+) T cells to differentiate into IL-10-producing Tr1 cells.However,the precise mechanisms by which these SSCs exert their regulatory functions in vivo remain undefined.Furthermore,their possible contribution to the development of allograft transplantation tolerance has yet to be examined.Here,we have used both murine skin and cardiac allograft transplantation models to explore whether in vivo alloresponses can be regulated by infusion with donor-derived SSCs and to investigate the possible mechanisms by which SSCs exert regulatory effects to prevent allograft rejection.We show that intravenous SSC infusion prolonged murine skin allograft survival.The prolonged graft survival is associated with augmentation of the generation of regulatory DC subsets and CD4^(+) CD25^(+) Foxp3^(+) regulatory T cells(Tregs),as well as upregulation of the production of suppressive cytokines IL-10 and transforming growth factor(TGF)-b.Moreover,we found that indoleamine 2,3-dioxygenase and SSC-derived regulatory DCs contribute to allograft protection by infusion of donor-specific SSCs.Our data suggest that donor-derived SSCs could be used as a therapeutic target to promote transplantation tolerance.