Royal jelly mediates fibrotic signaling, collagen cross-linking and cell proliferation in cardiac fibroblasts.

Royal jelly (RJ) is a multifunctional bee product with a unique composition and wide-ranging biological properties, including antioxidant, anti-inflammatory and antiproliferative activities. Still, little is known about the possible myocardial protective properties of RJ. Considering that sonication could enhance RJ bioactivity, this study aimed to assess the effects of non-sonicated (NS) and sonicated (S) RJ on fibrotic signaling, cell proliferation, and collagen production in cardiac fibroblasts. S-RJ was produced by ultrasonication at 20 kHz. Ventricular fibroblasts isolated from neonatal rats were cultured and treated with different concentrations of NS-RJ or S-RJ (0, 50, 100, 150, 200, and 250 µg/well). S-RJ significantly depressed the expression levels of transglutaminase 2 (TG2) mRNA across all the concentrations tested and was inversely associated with the expression of this profibrotic marker. S-RJ and NS-RJ displayed distinct dose-dependent effects on mRNA expression of several other profibrotic, proliferation, and apoptotic markers. Unlike NS-RJ, S-RJ elicited strong negative dose-dependent relationships with the expression of profibrotic markers (TG2, COL1A1, COL3A1, FN1, CTGF, MMP-2, α-SMA, TGF-ß1, CX43, periostin), as well as proliferation (CCND1) and apoptotic (BAX, BAX/BCL-2) markers, indicating that RJ dose-response effects were significantly modified by sonification. NS-RJ and S-RJ increased the content of soluble collagen, while decreasing collagen cross-linking. Collectively, these findings show that S-RJ has a greater range of action than NS-RJ for downregulating the expression of biomarkers associated with cardiac fibrosis. Reduced biomarker expression and collagen cross-linkages upon cardiac fibroblast treatment with specific concentrations of S-RJ or NS-RJ suggests putative roles and mechanisms by which RJ may confer some protection against cardiac fibrosis.

Inhibition of transglutaminase 2 (TG2) ameliorates ventricular fibrosis in isoproterenol-induced heart failure in rats.

AIMS: Transglutaminase (TG) inhibitors represent promising therapeutic interventions in cardiac fibrosis and related dysfunctions. However, it remains unknown how TG inhibition, TG2 in particular, affects the signaling systems that drive pathological fibrosis. This study aimed to examine the effect TG inhibition by cystamine on the progression of isoproterenol (ISO)-induced cardiac fibrosis and dysfunction in rats. MATERIALS AND METHODS: Cardiac fibrosis was established by intraperitoneal injection of ISO to rats (ISO group), followed by 6 weeks of cystamine injection (ISO + Cys group). The control groups were administered normal saline alone or with cystamine. Hemodynamics, lipid profile, liver enzymes, urea, and creatinine were assessed in conjunction with heart failure markers (serum NT-proANP and cTnI). Left ventricular (LV) and atrial (LA) fibrosis, total collagen content, and mRNA expression of profibrotic markers including TG2 were quantified by Masson's trichrome staining, LC-MS/MS and quantitative PCR, respectively. KEY FINDINGS: Cystamine administration to ISO rats significantly decreased diastolic and mean arterial pressures, total cholesterol, triglycerides, LDL, liver enzymes, urea, and creatinine levels, while increasing HDL. NT-proANP and cTnI serum levels remained unchanged. In LV tissues, significant reductions in ISO-induced fibrosis and elevated total collagen content were achieved after cystamine treatment, together with a reduction in TG2 concentration. Reduced mRNA expression of several profibrotic genes (COL1A1, FN1, MMP-2, CTGF, periostin, CX43) was also evidenced in LV tissues of ISO rats upon cystamine administration, whereas TGF-ß1 expression was depressed in LA tissues. Cystamine decreased TG2 mRNA expression in the LV of control rats, while LV expression of TG2 was relatively low in ISO rats irrespective of cystamine treatment. SIGNIFICANCE: TG2 inhibition by cystamine in vivo exerted cardioprotective effects against ISO-induced cardiac fibrosis in rats decreasing the LV abundance of several profibrotic markers and the content of TG2 and collagen, suggesting that TG2 pharmacological inhibition could be beneficial to alleviate cardiac fibrosis.

Vitamin D Ameliorates the Hepatic Oxidative Damage and Fibrotic Effect Caused by Thioacetamide in Rats.

Vitamin D3 (VD3) is a sunshine hormone that regulates cellular proliferation, differentiation, apoptosis, and angiogenesis related to liver parenchyma. We used a thioacetamide (TAA)-induced hepatic fibrosis rat model in our study to investigate the beneficial roles of VD3 to overcome extensive liver fibrosis. Randomly, four equal groups (eight rats per group) underwent therapy for eight successive weeks: a control group, a group treated with TAA 100 mg/kg BW IP every other day, a group treated with VD3 1000 IU/kg BW IM every day, and a TAA+VD group treated with both therapies. Treatment with VD3 after TAA-induced hepatic fibrosis was found to alleviate elevated liver function measures by decreasing ALT, AST, and ALP activity; decreasing total bilirubin, direct bilirubin, cholesterol, and triglyceride levels; and increasing glucose and 25[OH]D3. Rats treated with VD3 showed marked decreases in MDA and increased SOD, CAT, and GSH levels. In addition, CD34 and FGF23 gene expressions were reduced after dual therapy. Liver sections from the TAA+VD group showed markedly decreased hepatic lesions, and Masson's trichrome stain showed a marked decrease in dense bluish-stained fibrous tissue. The immunohistochemical expression of TGF-ß and α-SMA showed markedly decreased positive brown cytoplasmic expression in a few hepatocytes, clarifying the antifibrotic effect of VD3 in hepatic fibrosis. In conclusion, VD3 alleviates hepatotoxicity and fibrosis caused by TAA.

Novel Preoperative Type IV Collagen to Predict the Risk of Hepatocellular Carcinoma in Patients with Hepatitis B Virus-Related Cirrhotic Portal Hypertension After Laparoscopic Splenectomy and Azygoportal Disconnection.

Purpose: Although laparoscopic splenectomy and azygoportal disconnection (LSD) can significantly decrease portal vein pressure and even the incidence of hepatocellular carcinoma (HCC) in patients with cirrhotic portal hypertension (CPH), postoperative HCC inevitably occurs in certain patients. The purpose of this study was to seek a novel preoperative non-invasive predictive indicator to predict the occurrence of postoperative HCC. Patients and Methods: From April 2012 to April 2022, we collected clinical data of 178 hepatitis B virus (HBV)-related CPH patients. Based on inverse treatment probability weighting, candidate variables for predicting postoperative HCC were determined by means analysis. Then, a novel preoperative non-invasive prediction indicator (ie, type IV collagen-alpha fetoprotein-fibrosis-4 score [IVAF-FIB-4]) was established based on candidate variables, and its predictive ability was explored. Results: Postoperative HCC occurred in 9 (5.1%) patients. Correlation analyses showed that the IVAF-FIB-4 had a significant positive correlation with HCC (r = 0.835, P < 0.001). IVAF-FIB-4 showed a high accuracy (the area under the receiver operating characteristic curve: 0.939, 95% confidence interval [CI]: 0.818-1.000; sensitivity: 88.9%; specificity: 93.5%). At the end of follow-up, the incidence density of HCC in patients with IVAF-FIB-4 (1) was significant higher than that in patients with IVAF-FIB-4 (0) (138.1/1000 vs 1.1/1000 person-years; rate ratio: 130.475, 95% CI: 16.318-1043.227). In logistic regression, IVAF-FIB-4 was an independent risk factor for HCC (odds ratio: 668.000, 95% CI: 53.895-8279.541; P < 0.001). Conclusion: IVAF-FIB-4 is a novel preoperative noninvasive predictive indicator for predicting postoperative HCC in HBV-related CPH patients after LSD, with satisfactory predictive ability.

Efficacy of probiotic Streptococcus thermophilus in counteracting TGF-ß1-induced fibrotic response in normal human dermal fibroblasts.

BACKGROUND: Abnormal and deregulated skin wound healing associated with prolonged inflammation may result in dermal fibrosis. Since the current therapeutic strategies revealed unsatisfactory, the investigation of alternative approaches such as those based on the use of specific probiotic strains could provide promising therapeutic options. In this study, we aimed to evaluate whether the lysate from S. thermophilus could antagonize the fibrogenic effects of TGF-ß1 in normal human dermal fibroblasts (NHDF). METHODS: NHDF were exposed to TGF-ß1 to establish a fibrotic phenotype. Proliferation rate and cell number were measured using the IncuCyte® Live Cell Imager system and the trypan blue dye exclusion test. Phenoconversion markers (α-SMA and fibronectin) and collagen I levels were assessed by western blot and immunofluorescence. The mRNA levels of TGF-ß1 were evaluated by RT-PCR. The Smad2/3 phosphorylation level as well as ß-catenin and PPARγ expression, were assessed by western blot. The cell contractility function and migration of NHDF were studied using collagen gel retraction assay, and scratch wound healing assay, respectively. The effects of S. thermophilus lysate, alone or combined with TGF-ß1, were evaluated on all of the above-listed parameters and markers associated with TGF-ß1-induced fibrotic phenotype. RESULTS: Exposure to the S. thermophilus lysate significantly reduced the key mediators and events involved in the abnormal activation of myofibroblasts by TGF-ß1 within the fibrotic profile. The S. thermophilus treatment significantly reduced cell proliferation, migration, and myo-differentiation. In addition, the treatment with probiotic lysate reduced the α-SMA, fibronectin, collagen-I expression levels, and affected the collagen contraction ability of activated dermal fibroblasts. Moreover, the probiotic targeted the TGF-ß1 signaling, reducing Smad2/3 activation, TGF-ß1 mRNA level, and ß-catenin expression through the upregulation of PPARγ. CONCLUSION: This is the first report showing that S. thermophilus lysate had a remarkable anti-fibrotic effect in TGF-ß1-activated NHDF by inhibiting Smad signaling. Notably, the probiotic was able to reduce ß-catenin and increase PPARγ levels. The findings support our point that S. thermophilus may help prevent or treat hypertrophic scarring and keloids.

Cyclo(Val-Pro) and Cyclo(Leu-Hydroxy-Pro) from Pseudomonas sp. (ABS-36) alleviates acute and chronic renal injury under in vitro and in vivo models (Ischemic reperfusion and unilateral ureter obstruction).

The study aimed to identify small molecules having potentiality in alleviating renal injury. Two natural compounds cyclo(Val-Pro) (1) and cyclo(Leu-Hydroxy-Pro) (2) were first evaluated under acute renal injury model of ischemic reperfusion at different doses of 25, 50 and 75 mg/kg body weight. Further, the compounds were subjected to antimycin A-induced ischemic in vitro study (NRK-52E cell lines). Both the compounds significantly decreased plasma IL-1ß levels (P < 0.05). Also, the mRNA expression levels of inflammatory markers (TNF-α, IL-6 and IL-1ß) and renal injury markers (KIM-1, NGAL, α-GST and π-GST) in the renal tissues were significantly alleviated (P < 0.01) along with the improvement in histological damage and control over neutrophil infiltration as a result of ischemic reperfusion. The in vitro study revealed the protective effect against antimycin A-induced cytotoxicity (P < 0.05) and antiapoptotic effect acting through the regulation of Bax, caspase 3 (pro and cleaved) and BCL2 with reduction in Annexin+PI+ cells. Further, the compound cyclo(Val-Pro) (1) was evaluated (50 mg/kg body weight dose) in chronic unilateral ureter obstruction model of renal injury in mice and TGF-ß-induced in vitro fibrotic model (NRK-49F cell lines). Cyclo(Val-Pro) (1) significantly reduced the expression levels of fibrotic markers (collagen-1, α-SMA and TGF-ß) and showed marked alleviation of renal fibrosis (sirius red staining). Also, the proliferation of TGF-ß-induced NRK-49F cells was significantly reduced along with decreased levels of collagen-1 and α-SMA in immunohistochemistry studies. In conclusion, the compounds significantly abrogated ischemic injury by inhibiting renal inflammation and tubular epithelial apoptosis. Further, cyclo (Val-Pro) (1) exhibited significant anti-fibrotic activity through the inhibition of fibroblast activation and proliferation. Thus, these proline-based cyclic dipeptides are recommended as drug leads for treating renal injury.

Novel noninvasive liver fibrotic markers to predict postoperative re-bleeding after laparoscopic splenectomy and azygoportal disconnection: a 1-year prospective study.

BACKGROUND: Esophagogastric variceal re-bleeding (EGVR) is a common and potentially lethal complication after open or laparoscopic splenectomy and azygoportal disconnection (LSD) in patients with cirrhosis and portal hypertension. Currently, noninvasive biomarkers for predicting EGVR are lacking. This prospective study focused on developing a noninvasive and convenient clinical model for predicting postoperative EGVR. METHODS: Between September 2014 and March 2017, we enrolled 164 patients with cirrhosis who successfully underwent LSD. Based on the absence or presence of EGVR, patients were divided into EGVR and non-EGVR groups. We used correlation analysis to determine significant candidate variables among the liver fibrotic markers procollagen type III (PC-III), hyaluronidase (HA), laminin (LN), and type IV collagen (C-IV). RESULTS: Postoperative EGVR occurred in 22 (13.41%) patients. Correlation analyses showed that LN (r = 0.375; p < 0.001) and C-IV (r = 0.349; p < 0.001) were significantly positively associated with EGVR. The area under the receiver operating characteristic curve (AUC) of LN was 0.817 (95% confidence interval [CI] 0.722-0.913); that of C-IV was 0.795 (95% CI 0.710-0.881). In logistic multivariate regression, cutoff values LN ≥ 64 µg/L and of C-IV ≥ 65 µg/L were independent risk factors for EGVR. LN ≥ 64 µg/L combined with C-IV ≥ 65 µg/L was the best performing model, with AUC 0.867 (95% CI 0.768-0.967). CONCLUSION: LN and C-IV are potential markers to predict EGVR. Combining the two markers showed satisfactory ability to predict EGVR in patients with cirrhosis and portal hypertension after LSD.

Acetylcholine decreases formation of myofibroblasts and excessive extracellular matrix production in an in vitro human corneal fibrosis model.

Acetylcholine (ACh) has been reported to play various physiological roles, including wound healing in the cornea. Here, we study the role of ACh in the transition of corneal fibroblasts into myofibroblasts, and in consequence its role in the onset of fibrosis, in an in vitro human corneal fibrosis model. Primary human keratocytes were obtained from healthy corneas. Vitamin C (VitC) and transforming growth factor-ß1 (TGF-ß1) were used to induce fibrosis in corneal fibroblasts. qRT-PCR and ELISA analyses showed that gene expression and production of collagen I, collagen III, collagen V, lumican, fibronectin (FN) and alpha-smooth muscle actin (α-SMA) were reduced by ACh in quiescent keratocytes. ACh treatment furthermore decreased gene expression and production of collagen I, collagen III, collagen V, lumican, FN and α-SMA during the transition of corneal fibroblasts into myofibroblasts, after induction of fibrotic process. ACh inhibited corneal fibroblasts from developing contractile activity during the process of fibrosis, as assessed with collagen gel contraction assay. Moreover, the effect of ACh was dependent on activation of muscarinic ACh receptors. These results show that ACh has an anti-fibrotic effect in an in vitro human corneal fibrosis model, as it negatively affects the transition of corneal fibroblasts into myofibroblasts. Therefore, ACh might play a role in the onset of fibrosis in the corneal stroma.

Substance P induces fibrotic changes through activation of the RhoA/ROCK pathway in an in vitro human corneal fibrosis model.

Fibrosis is characterized by hardening, overgrowth, and development of scars in various tissues as a result of faulty reparative processes, diseases, or chronic inflammation. During the fibrotic process in the corneal stroma of the eye, the resident cells called keratocytes differentiate into myofibroblasts, specialized contractile fibroblastic cells that produce excessive amounts of disorganized extracellular matrix (ECM) and pro-fibrotic components such as alpha-smooth muscle actin (α-SMA) and fibronectin. This study aimed to elucidate the role of substance P (SP), a neuropeptide that has been shown to be involved in corneal wound healing, in ECM production and fibrotic markers expression in quiescent human keratocytes, and during the onset of fibrosis in corneal fibroblasts, in an in vitro human corneal fibrosis model. We report that SP induces keratocyte contraction and upregulates gene expression of collagens I, III, and V, and fibrotic markers: α-SMA and fibronectin, in keratocytes. Using our in vitro human corneal fibrosis model, we show that SP enhances gene expression and secretion of collagens I, III, and V, and lumican. Moreover, SP upregulates gene expression and secretion of α-SMA and fibronectin, and increases contractility of corneal fibroblasts during the onset of fibrosis. Activation of the preferred SP receptor, the neurokinin-1 receptor (NK-1R), is necessary for the SP-induced pro-fibrotic changes. In addition, SP induces the pro-fibrotic changes through activation of the RhoA/ROCK pathway. Taken together, we show that SP has a pro-fibrotic effect in both quiescent human keratocytes and during the onset of fibrosis in an in vitro human corneal fibrosis model.

Chitosan-based scaffold counteracts hypertrophic and fibrotic markers in chondrogenic differentiated mesenchymal stromal cells.

Cartilage tissue engineering remains problematic because no systems are able to induce signals that contribute to native cartilage structure formation. Therefore, we tested the potentiality of gelatin-polyethylene glycol scaffolds containing three different concentrations of chitosan (CH; 0%, 8%, and 16%) on chondrogenic differentiation of human platelet lysate-expanded human bone marrow mesenchymal stromal cells (hBM-MSCs). Typical chondrogenic (SOX9, collagen type 2, and aggrecan), hypertrophic (collagen type 10), and fibrotic (collagen type 1) markers were evaluated at gene and protein level at Days 1, 28, and 48. We demonstrated that 16% CH scaffold had the highest percentage of relaxation with the fastest relaxation rate. In particular, 16% CH scaffold, combined with chondrogenic factor TGFß3, was more efficient in inducing hBM-MSCs chondrogenic differentiation compared with 0% or 8% scaffolds. Collagen type 2, SOX9, and aggrecan showed the same expression in all scaffolds, whereas collagen types 10 and 1 markers were efficiently down-modulated only in 16% CH. We demonstrated that using human platelet lysate chronically during hBM-MSCs chondrogenic differentiation, the chondrogenic, hypertrophic, and fibrotic markers were significantly decreased. Our data demonstrate that only a high concentration of CH, combined with TGFß3, creates an environment capable of guiding in vitro hBM-MSCs towards a phenotypically stable chondrogenesis.

MicroRNA­219 overexpression serves a protective role during liver fibrosis by targeting tumor growth factor ß receptor 2.

Progressive liver fibrosis is the primary cause of liver cirrhosis and hepatocellular carcinoma, and leads to considerable morbidity and mortality. Recent studies have demonstrated that microRNAs (miRNAs or miRs) are associated with fibrotic processes in liver disorders, although the exact role of miR­219 remains unclear and the relevant mechanisms remain to be completely understood. To the best of our knowledge, the present study was the first to demonstrate the functional implications of miR­219 expression during liver fibrosis. The present study reported that miR­219 exhibited significantly reduced expression in serum from patients and that its expression was negatively associated with clinical stage. It was also demonstrated that miR­219 attenuated angiotensin II­induced expression of pro­fibrotic markers, including α­smooth muscle actin, atlastin GTPase 1 and collagen. Additionally, a CCl4­induced mouse liver injury model was used to demonstrate that miR­219 strongly suppressed liver fibrosis in vivo. Furthermore, the present study identified tumor growth factor ß receptor 2 (TGFBR2) as a direct target gene of miR­219. In conclusion, the results of the present study revealed that miR­219 may regulate pro­fibrotic markers by directly targeting the TGFBR2 gene and the miR­219/TGFBR2 signaling pathway may be a potential therapeutic target for liver fibrosis.

Clinical significance of fibrotic, haemostatic and endotoxic changes in patients with liver cirrhosis.

BACKGROUND AND STUDY AIMS: To investigate the relationship among fibrotic, haemostatic and endotoxic changes in patients with different degrees of liver cirrhosis. PATIENTS AND METHODS: Liver fibrotic markers, including hyaluronic acid (HA), Ccollagen IV (Col-IV), laminin (LN), and N-terminal pro-peptide of collagen type III (PIIINP), were determined by radioimmunoassay. A series of haemostatic tests, including prothrombin time (PT), international normalized ratio, activated partial thromboplastin time, antithrombin-III, thrombin time, fibrinogen, fibrin(ogen) degradation product and D-dimer were determined using an automatic coagulation analyszer. Plasma levels of endotoxin were detected quantitatively using an endotoxin detection kit. Correlation analysis of the data was performed. RESULTS: Based on Child-Pugh classification, statistically significant differences in fibrotic markers and haemostatic parameters were found in 249 patients with liver cirrhosis, while no significant differences in endotoxin levels were observed. Based on ascites classification, statistically significant differences in fibrotic markers (such as HA, Col-IV and PIIINP, except for LN) and haemostatic parameters were found. As for endotoxin levels, there were significant differences between the ascites, spontaneous bacterial peritonitis (SBP) and no-ascites groups, while no significant differences were observed between the ascites and SBP groups. Correlation analysis demonstrated some correlation among fibrotic markers, haemostatic parameters and endotoxin. CONCLUSIONS: A close relationship exists between the severity of cirrhosis and fibrotic changes, as well as haemostatic changes. Endotoxin may be an important contributing factor to the development of ascites in cirrhosis. Some correlation may exist between fibrosis, haemostatic and endotoxin.

Biochemical and Molecular Mechanisms of Platelet-Rich Plasma in Ameliorating Liver Fibrosis Induced by Dimethylnitrosurea.

BACKGROUND/AIMS: Hepatic fibrosis is a wound-healing process in the chronically injured liver. Clinical application of platelet-rich plasma (PRP) is of considerable interest for wound healing and regeneration. In view of the regeneration effect of PRP, we designed this study to explore the hypothesis that PRP could play a role in improving the biochemical and molecular changes that occur in liver fibrosis induced by dimethylnitrosamine (DMN) in rats. METHODS: Four groups were studied: control, PRP control, DMN (liver fibrosis), and DMN+PRP groups. Serum liver enzymes (alanine amino transferase ALT, aspartate amino transferase AST, gamma glutamyl transferase GGT, and lactate dehydrogenase LDH), and liver hydroxyproline content were measured colorimetrically.Interleukin-8 (IL-8) and B-cell lymphoma (Bcl2) were determined by enzyme-linked immunosorbent assay. And the expression levels of alpha-smooth muscle actin (α-SMA) ,transforming growth factor (TGF-ß), and nuclear factor kappa B1(NF-қB1) were evaluated by quantitative real-time polymerase chain reaction. RESULTS: Our results showed that PRP markedly improved the DMN-induced changes in liver enzymes accompanied by a significant decrease in liver hydroxyproline content and IL-8 level induced by DMN, and an increase in the anti-apoptotic marker Bcl-2. PRP also showed significant down-regulation of fibrosis-related genes α-SMA and TGF-ß and a significant decrease in the inflammatory marker NF-қB1. CONCLUSION: Based on these encouraging results, we consider that PRP could be a promising new agent for liver regeneration and alleviation of fibrosis.

Predicting pulmonary fibrosis in humans after exposure to multi-walled carbon nanotubes (MWCNTs).

The increased production and use of multi-walled carbon nanotubes (MWCNTs) in a diverse array of consumer, medical, and industrial applications have raised concerns about potential human exposure to these materials in the workplace and ambient environments. Inhalation is a primary route of exposure to MWCNTs, and the existing data indicate that they are potentially hazardous to human health. While a 90-day rodent inhalation test (e.g., OECD Test No. 413: subchronic inhalation toxicity: 90-day study or EPA Health Effects Test Guidelines OPPTS 870.3465 90-day inhalation toxicity) is recommended by the U.S. Environmental Protection Agency Office of Pollution Prevention and Toxics for MWCNTs (and other CNTs) if they are to be commercially produced (Godwin et al. in ACS Nano 9:3409-3417, 2015), this test is time and cost-intensive and subject to scientific and ethical concerns. As a result, there has been much interest in transitioning away from studies on animals and moving toward human-based in vitro and in silico models. However, given the multiple mechanisms of toxicity associated with subchronic exposure to inhaled MWCNTs, a battery of non-animal tests will likely be needed to evaluate the key endpoints assessed by the 90-day rodent study. Pulmonary fibrosis is an important adverse outcome related to inhalation exposure to MWCNTs and one that the non-animal approach should be able to assess. This review summarizes the state-of-the-science regarding in vivo and in vitro toxicological methods for predicting MWCNT-induced pulmonary fibrosis.

Expression of the transcriptional regulator snail1 in kidney transplants displaying epithelial-to-mesenchymal transition features.

BACKGROUND: The epithelial response to injury is stereotypical and reminiscent of epithelial-to-mesenchymal transitions (EMTs), such as those observed during embryogenesis and tumour metastasis. In the context of solid organ transplantation, EMT-like features are often acquired by epithelial cells and are predictive of graft fibrosis. Here, we studied the possible involvement of several major transcriptional regulators, including snail1, phospho-Smad 2/3 and zeb1, in EMT induction in human renal grafts. METHODS: We used immunohistochemistry to detect the presence of these EMT transcriptional regulators along with that of two validated EMT markers (intra-cytoplasmic translocation of ß-catenin, de novo expression of vimentin), in 103 renal graft biopsy samples taken for routine surveillance or for a clinical indication. RESULTS: We observed the nuclear accumulation of snail1 and phospho-smad2/3 in tubular cells displaying EMT. The level of snail1 was significantly correlated with the scores of EMT markers (ß-catenin: ρ = 0.94, P < 0.0001; vimentin: ρ = 0.93, P < 0.0001) and with deteriorated graft function and proteinuria at the time of biopsy. Furthermore, intense staining for both snail1 and vimentin in tubular cells (≥10% of tubules) was predictive of graft dysfunction 21 months post-biopsy, independently of the other known risk factor for long-term graft dysfunction. In contrast, in both normal and diseased graft, zeb1 expression was detected exclusively in the endothelial cells of glomeruli and peritubular capillaries. CONCLUSION: This study suggests that snail1 is closely related to the fibrogenic, EMT-like response of the tubular epithelium in human renal grafts and predictive of graft function loss.