Mycophenolate mofetil inhibits macrophage infiltration and kidney fibrosis in long-term ischemia-reperfusion injury

Single-Cell transcriptomes of immune cells provide insights into the therapeutic effects of mycophenolate mofetil on autoimmune uveitis

Mycophenolate mofetil (MMF) is an immunosuppressive agent widely applied in various autoimmune diseases, including autoimmune uveitis, a sight-threatening autoimmune disease mainly affecting the eyes. However, the mechanisms of action are not comprehensively understood. To investigate the potential impact of MMF on uveitis, we generated single-cell RNA sequence data from normal, experimental autoimmune uveitis (EAU) and MMF-treated EAU mice. We observed that some EAU-induced transcriptional changes were reversed by MMF treatment. Transcriptional data indicated that MMF may have a general inhibitory effect on the activation of immune cells during EAU. Each immune cell type showed a different response to MMF treatment. Pseudotime analysis showed that MMF treatment partly reversed the increased differentiation tendency from naïve to effector phenotypes of T and B cells in EAU. The reduced proportion of T-helper (Th)1 and T-helper (Th)17 cells after MMF treatment was confirmed using flow cytometry. MMF treatment downregulated the EAU-associated upregulation of several molecules (such as Cebpd, Pim1, Furin, Bhlhe40, and Hif1a) that promote pathogenic cytokine production by T helper (Th)-1 and Th17 cells. Abnormally enhanced immunoglobulin production, antigen processing, and presentation ability of B cells may also be inhibited by MMF treatment. In addition to T and B cells, MMF treatment countered EAU-induced transcriptional changes in other immune cells to different degrees. Overall, our findings provide novel insights into the mechanisms underlying MMF treatment and indicate that the therapeutic effect of MMF is not driven by a single molecule.

Metabolic tissue-resident CD8+ T cells: A key player in obesity-related diseases

Obesity-induced low-grade chronic inflammation in the metabolic tissues, such as adipose tissue (AT) and liver tissue, in individuals with obesity is a major etiological factor for several diseases, such as insulin resistance, type 2 diabetes, fatty liver disease, atherosclerosis and cardiovascular problems, as well as cancer and autoimmune diseases. Previous studies have revealed that tissue-resident macrophages play a crucial role in this process. However, the mechanisms responsible for recruiting and activating macrophages and initiating chronic inflammation in the metabolic tissues have not yet been clearly elucidated. In the most recent decade, there has been a growing emphasis on the critical role of the adaptive CD8⁺ T cells in obesity-induced chronic inflammation and related metabolic diseases. In this review, we will summarize the relevant studies in both mice and human regarding the role of metabolic tissue-resident CD8⁺ T cells in obesity-related inflammation and diseases, as well as the possible mechanisms underlying the regulation of CD8⁺ T cell recruitment, activation and function in the metabolic tissues, and discuss their potential as therapeutic targets for obesity-related diseases.

Long-term Efficacy and Safety of Everolimus Versus Mycophenolate in Kidney Transplant Recipients Receiving Tacrolimus

BACKGROUND

The short-term efficacy and safety of everolimus in combination with tacrolimus have been described in several clinical trials. Yet, detailed long-term data comparing the use of everolimus or mycophenolate in kidney transplant recipients receiving tacrolimus is lacking.

METHODS

This is a 5-year follow-up post hoc analysis of a prospective trial including 288 patients who were randomized to receive a single 3 mg/kg dose of rabbit antithymocyte globulin, tacrolimus, everolimus, and prednisone (r-ATG/EVR, n=85); basiliximab, tacrolimus, everolimus, and prednisone (BAS/EVR, n=102); or basiliximab, tacrolimus, mycophenolate, and prednisone (BAS/MPS, n=101).

RESULTS

There were no differences in the incidence of treatment failure (31.8% vs. 40.2% vs. 34.7%, p=0.468), de novo donor-specific HLA antibodies (6.5 vs. 11.7 vs. 4.0%, p=0.185), patient (92.9% vs. 94.1% vs. 92.1%, p = 0.854) and death-censored graft (87.1% vs. 90.2% vs. 85.1%, p = 0.498) survivals. Using a sensitive analysis, the trajectories of eGFR were comparable in the intention-to-treat (p=0.145) and per protocol (p=0.354) populations. There were no differences in study drug discontinuation rate (22.4% vs. 30.4% vs. 17.8%, p=0.103).

CONCLUSIONS

In summary, this analysis in a cohort of de novo low/moderate immunologic risk kidney transplant recipients suggests that the use of a single 3mg/kg r-ATG dose followed by EVR combined with reduced TAC concentrations was associated with similar efficacy and renal function compared to the standard of care immunosuppressive regimen.Supplemental Visual Abstract; http://links.lww.com/TP/C160.

Toll-like receptor 4: An attractive therapeutic target for acute kidney injury

Acute kidney injury (AKI) is a progressive renal complication which significantly affects the patient's life with huge economic burden. Untreated acute kidney injury eventually progresses to a chronic form and end-stage renal disease. Although significant breakthroughs have been made in recent years, there are still no effective pharmacological therapies for the treatment of acute kidney injury. Toll-like receptor 4 (TLR4) is a well-characterized pattern recognition receptor, and increasing evidence has shown that TLR4 mediated inflammatory response plays a pivotal role in the pathogenesis of acute kidney injury. The expression of TLR4 has been seen in resident renal cells, including podocytes, mesangial cells, tubular epithelial cells and endothelial cells. Activation of TLR4 signaling regulates the transcription of numerous pro-inflammatory cytokines and chemokines, resulting in renal inflammation. Therefore, targeting TLR4 and its downstream effectors could serve as an effective therapeutic intervention to prevent renal inflammation and subsequent kidney damage. For the first time, this review summarizes the literature on acute kidney injury from the perspective of TLR4 from year 2010 to 2020. In the current review, the role of TLR4 signaling pathway in AKI with preclinical evidence is discussed. Furthermore, we have highlighted several compounds of natural and synthetic origin, which have the potential to avert the renal TLR4 signaling in preclinical AKI models and have shown protection against AKI. This scientific review provides new ideas for targeting TLR4 in the treatment of AKI and provides strategies for the drug development against AKI.

Mycophenolate mofetil preconditioning protects mouse liver against ischemia/reperfusion injury in wild type and toll-like receptor 4 knockout mice

BACKGROUND

Mycophenolate mofetil (MMF), an immunosuppressive drug, exerts anti-inflammatory effects on organs during ischemia/reperfusion (I/R) injury. However, the exact function of MMF in hepatic I/R injury remains largely unknown. The purpose of this study was to explore the role and potential mechanism of MMF protection in hepatic I/R injury.

METHODS

Male wild type (WT) and TLR4 knockout (KO) mice were injected intraperitoneally with MMF or normal saline. Animals underwent 90 min of partial hepatic ischemia, followed by 1, 6, or 24 h of reperfusion. Hepatic histology, serum amiotransferase, inflammatory cytokines, hepatocyte apoptosis, and hepatocyte autophagy were examined to assess liver injury.

RESULTS

Treatment with MMF significantly decreased hepatic I/R injury as indicated by a reduction in serum aminotransferase levels, Suzuki scores, and the overall degree of necrosis. MMF treatment inhibited TLR4 activation dramatically. MMF administration also significantly inhibited the activation of the NF-κB pathway and the expression of pro-inflammatory cytokines. In TLR4 KO mice, MMF still exerted protection from hepatic I/R injury. MMF treatment inhibited hepatocyte apoptosis, as indicated by reduced TUNEL staining, and reduced the accumulation of cleaved caspase-3. In addition, MMF may induce autophagy and increase autophagic flux before and after hepatic reperfusion by augmenting the expression of LC3-II, P62, and Beclin-1. The induction of autophagy by MMF treatment may be related to TLR4 activation.

CONCLUSIONS

Our results indicate that MMF treatment ameliorates hepatic I/R injury. The mechanism of action likely involves the ability of MMF to decrease apoptosis and the inflammatory response while inducing autophagy.

The effect of rituximab on encapsulated peritoneal sclerosis in an experimental rat model

Background/aim

 Peritoneal sclerosis may be observed in varied manifestations. However, the most serious form is the encapsulated peritoneal sclerosis. We researched the effect of rituximab on peritoneal fibrosis in an experimental rat model.

Materials and methods

Twenty-four Wistar Albino rats were divided into 4 equal groups. During weeks 0–3; group I received isotonic saline (IS) solution, group II, group III, and group IV received chlorhexidine gluconate (CG) via intraperitoneal (i.p.) route. In the next 3 weeks nothing adminestred to both group I and group II but IS solution was adminestred to group III via i.p. route and 375 mg/m2/week rituximab was applied intravenously on days 21, 28, and 35 to group IV. Fibrosis, peritoneal thickness, and inflammation were evaluated. Immunohistochemical methods used for the detection of matrix MMP-2, TGF-β1, and VGEF expressions.

Results

  The rituximab (group IV) had significantly lower fibrosis and peritoneal thickness scores than the group II and III (P < 0.001). TGF-β1 and VEGF expressions were significantly lower in the rituximab group than in the group II and III (P < 0.001).Conclusion: We found that rituximab had a significant effect on the peritoneal thickness, total fibrosis, TGF-β1 and VGEF scores which were induced by CG.

Mycophenolate mofetil improves renal haemodynamics, microvascular oxygenation, and inflammation in a rat model of supra-renal aortic clamping-mediated renal ischaemia reperfusion injury

Ischaemia/reperfusion (I/R) is one of the main causes of acute kidney injury (AKI), which is characterized by sterile inflammation and oxidative stress. Immune cell activation can provoke overproduction of inflammatory mediators and reactive oxygen species (ROS), leading to perturbation of the microcirculation and tissue oxygenation associated with local and remote tissue injury. This study investigated whether the clinically employed immunosuppressant mycophenolate mofetil (MMF) was able to reduce I/R-induced renal oxygenation defects and oxidative stress by preventing sterile inflammation. Rats were divided into three groups (n=6/group): (1) a sham-operated control group; (2) a group subjected to renal I/R alone (I/R); and (3) a group subjected to I/R and MMF treatment (20 mg/kg prior to I/R) (I/R+MMF). Ischaemia was induced by a vascular occluder placed on the abdominal aorta for 30 minutes, followed by 120 minutes of reperfusion. Renal I/R deteriorated renal oxygenation (P<.001) and oxygen delivery (P<.01), reduced creatinine clearance (P<.01) and tubular sodium reabsorption (P<.001), and increased iNOS, renal tissue injury markers (P<.001), and IL-6 (P<.001). Oral MMF administration prior to insult restored renal cortical oxygenation (P<.05) and iNOS, renal injury markers, and inflammation parameters (P<.001) to near-baseline levels without affecting renal function. MMF exerted a prophylactic effect on renal microvascular oxygenation and abrogated tissue inflammation and renal injury following lower body I/R-induced AKI. These findings may have clinical implications during major vascular or renal transplant surgery.

Longterm Data on Disease Flares in Patients with Proliferative Lupus Nephritis in Recent Years

Objective.

To examine the disease flare rate in lupus nephritis (LN), focusing on renal flares, and the factors associated with relapse risk in recent years.

Methods.

We analyzed data on 139 Chinese patients with class III/IV ± V LN diagnosed from January 1983 to December 2013. We also compared data before and after 1998, when maintenance immunosuppression was changed from azathioprine (AZA) to mycophenolic acid (MPA).

Results.

Over 112.5 ± 88.4 months, 135 episodes of renal flare occurred, giving a flare rate of 0.108 episodes per patient-year. The renal relapse-free survival rate was 96%, 90%, 86%, 80%, 69%, and 57% after 1, 2, 3, 4, 5, and 10 years, respectively, calculated from the start of induction treatment. Reduced risk of flare was associated with MPA maintenance (OR 0.314, 95% CI 0.099–0.994, p = 0.049), complete remission after induction immunosuppression (OR 0.329, 95% CI 0.133–0.810, p = 0.016), and diagnosis after 1998 (OR 0.305, 95% CI 0.133–0.700, p = 0.005). Relapse-free survival was significantly better in patients treated with prednisolone and MPA as maintenance immunosuppression (91% after 5 yrs and 83% after 10 yrs, respectively) compared with prednisolone and AZA (70% and 52%, respectively, p = 0.044). LN diagnosed in 1998–2013 showed 5-year and 10-year relapse-free survival rates of 93% and 86%, respectively, compared with 81% and 66%, respectively (p = 0.017) for LN that presented in 1983–1997.

Conclusion.

Our data show a relatively low flare rate for LN in the more recent era, attributed to effective induction of immunosuppression and MPA as maintenance treatment.

Protective effects of tacrolimus on podocytes in early diabetic nephropathy in rats

The aim of the present study was to investigate the protective effect of tacrolimus on early podocyte damage in rats with diabetic nephropathy (DN). A total of 38 normal male Sprague‑Dawley rats were randomly divided into four groups: Normal control group (group N; n=8), DN group (n=10), tacrolimus (FK506) treatment group (group F; n=10), benazepril (Lotensin) treatment group (group L; n=10). The rats in groups DN, F and L were administered with streptozotocin (STZ; 60 mg/kg) by intraperitoneal injection to establish the diabetic rat model. After 4 weeks, the diabetic rat model was established, and rats in the different groups were administered intragrastically with the respective drugs. Blood glucose (BS), body weight (BW) and 24‑h urine protein were detected every 4 weeks, serum creatinine (SCr), blood urea nitrogen (BUN) and kidney weight/body weight (KW/BW) were measured at the end of the 8 weeks of drug treatment. Renal pathological changes were observed under a light microscope and electron microscope. Expression of nephrin, which is a podocyte‑specific marker, was detected using western blot analysis. The results showed that the levels of SCr, BUN, KW/BW and 24‑h urine protein in groups D, F and L were significantly higher, compared with those in group N (P<0.05). No significant differences were found between groups F and L for the above indicators, with the exception of BS. However, all indices were significantly lower, compared with those in group DN (P<0.05). Renal pathological expression was normal in group N under light microscopy. There were significant increases in the glomerular volume, proliferative mesangial cells, width of the mesangial area and thickness of the basement membrane in group DN, however, all the above pathological characteristics were reduced in groups F and L, compared with group DN (P<0.05). No significant difference was found between groups F and L. A widened glomerular basement membrane, and disorder, widening and fusion of podocyte processes were observed under the electron microscope in group DN, however, these were reduced in groups F and L, compared with group DN (P<0.05). The results of the western blot analysis showed that the expression of nephrin decreased by 60.1% in group DN, compared with group N, and significant recovery in the expression of nephrin was observed in groups F and L (P<0.05). Tacrolimus reduced urinary protein and slowed the progression of DN, partially by recovering the protein expression of nephrin in the renal tissue of diabetic rats, and maintaining the integrity of the structure and function of podocytes.

Renal inflammation and injury are associated with lymphangiogenesis in hypertension

Lymphatic vessels are vital for the trafficking of immune cells from the interstitium to draining lymph nodes during inflammation. Hypertension is associated with renal infiltration of activated immune cells and inflammation; however, it is unknown how renal lymphatic vessels change in hypertension. We hypothesized that renal macrophage infiltration and inflammation would cause increased lymphatic vessel density in hypertensive rats. Spontaneously hypertensive rats (SHR) that exhibit hypertension and renal injury (SHR-A3 strain) had significantly increased renal lymphatic vessel density and macrophages at 40 wk of age compared with Wistar-Kyoto (WKY) controls. SHR rats that exhibit hypertension but minimal renal injury (SHR-B2 strain) had significantly less renal lymphatic vessel density compared with WKY rats. The signals for lymphangiogenesis, VEGF-C and its receptor VEGF-R3, and proinflammatory cytokine genes increased significantly in the kidneys of SHR-A3 rats but not in SHR-B2 rats. Fischer 344 rats exhibit normal blood pressure but develop renal injury as they age. Kidneys from 24-mo- and/or 20-mo-old Fischer rats had significantly increased lymphatic vessel density, macrophage infiltration, VEGF-C and VEGF-R3 expression, and proinflammatory cytokine gene expression compared with 4-mo-old controls. These data together demonstrate that renal immune cell infiltration and inflammation cause lymphangiogenesis in hypertension- and aging-associated renal injury.

Abatacept as a therapeutic option in the treatment of encapsulated peritoneal sclerosis: an experimental rat model

PURPOSE

Encapsulated peritoneal sclerosis (EPS) is a rare complication of long-term peritoneal dialysis (PD) and is usually associated with mortality. Inflammation is a leading factor for developing EPS. This study aimed to investigate the effect of abatacept on peritoneal fibrosis and inflammation using the EPS rat model.

METHODS

Twenty-four Wistar albino rats were randomly divided into four equal groups. Group I (control group) was administered isotonic saline (IS) via the intraperitoneal (ip) route during weeks 0-3. Chlorhexidine gluconate (CG) ip was administered to group II (CG group) during weeks 0-3. Group III (CG + IS group) received CG for the first 21 days and IS solution for the following 3 weeks. Group IV (abatacept group) received CG during weeks 0-3, and subsequently, 50 mcg/day abatacept during weeks 4-6. Peritoneal thickness, fibrosis, and inflammation were examined using light microscopy. Expressions of matrix metalloproteinase-2 (MMP-2) and transforming growth factor-beta 1 (TGF-β1) were detected by immunohistochemical staining.

RESULTS

Lesser peritoneal thickness and lower inflammation score were observed in the abatacept group than in the CG and CG + IS groups (p < 0.05). Furthermore, the abatacept group had a lower fibrosis score than the CG + IS group (p < 0.05). MMP-2 and TGF-β1 scores were lower in the abatacept group than in the CG + IS group (p < 0.05).

CONCLUSIONS

The results revealed that abatacept had a histopathological beneficial effect on peritoneal fibrosis, inflammation, MMP-2, and TGF-β1 scores, which were induced by CG. Abatacept could be a new therapeutic option for treating EPS.

Protective effect of mycophenolate mofetil on residual renal function in peritoneal dialysis patients: An open label feasibility study

AIM

This study aims to evaluate the safety of mycophenolate mofetil (MMF) and its effect on residual renal function (RRF) during peritoneal dialysis (PD).

METHODS

This is a prospective, randomized study comprising 60 PD patients. The patients were assigned either to the MMF group (MMF dosage: 1.0-1.5 g/day in two divided doses for 6 months, followed by a dose of 0.5-0.75 g/day for another 6 months) or to the control group. The patients close monitoring for 1 year. Variables related to residual renal function, including urine volume, measured glomerular filtration rate (GFR), and renal Kt/V, were measured at four time points.

RESULTS

There were no significant changes in urinary protein excretion in either group (P > 0.05). The MMF group showed a significantly higher urine volume than the control group (955.38 ± 243.54 vs 786.15 ± 279.62 mL/day, P = 0.024). The renal kt/V was also significantly higher in the MMF group (0.59 ± 0.11 in MMF vs 0.50 ± 0.19 in control group, P = 0.032). There was significant difference in the renal measured GFR between the two groups at 6, 9 and 12 months (MMF vs control at 6 months, 6.14 ± 0.66 vs 5.58 ± 0.65 mL/min per 1.73m² , P = 0.003; at 9 months, 5.68 ± 0.80 vs 4.78 ± 0.75, P < 0.001; at 12 months, 5.44 ± 0.91 vs 4.43 ± 0.93, P < 0.001). MMF was well tolerated without any serious complications.

CONCLUSION

The use of MMF in PD patients tends to better preserve RRF.

Donor-Specific Anti-HLA Antibodies and Endothelial C4d Deposition-Association With Chronic Liver Allograft Failure

BACKGROUND

The significance of humoral immune response for allograft survival after liver transplantation (LT) is still a matter of debate. The aim of this cross-sectional study was to assess immunological and clinical factors associated with advanced fibrosis (F3-F4) and chronic graft failure in LT recipients.

METHODS

Serum samples from 174 patients prospectively enrolled and followed up for 12 months were tested for anti-HLA antibodies and compared against donor HLA types. Immunohistochemical C4d staining was performed on formalin-fixed, paraffin-embedded liver tissue.

RESULTS

Mean time period from LT to enrollment was 66.9 ± 51.9 months. Independent predictive factors for graft failure included donor-positive cytomegalovirus serostatus (P = 0.02), donor-specific antibodies (DSA) against HLA class II (P = 0.03), donor age (P = 0.01), hepatitis C virus allograft reinfection (P = 0.0008), and biliary complications (P = 0.003). HLA class II DSA and HLA class I antibody positivity, hepatitis C virus reinfection, and mycophenolate mofetil-free regimens were significant risk factors for advanced fibrosis after LT. There was a significant association between C4d deposition on allograft endothelial cells and presence of class II DSA (P < 0.0001). Patients with C4d deposits had a 4.3 times higher risk of graft failure than those with negative staining and a significantly lower median time to graft failure (94.6 months [range, 3.6-158.9 months] vs 176.4 months [range, 9.4-217.8 months], P < 0.0001).

CONCLUSIONS

Screening for HLA DSA might be useful for early identification of LT recipients at increased risk of graft failure who could benefit from closer surveillance and tailored immunosuppressive regimens.

Mycophenolate Mofetil Ameliorates Diabetic Nephropathy in db/db Mice

Chronic low-grade inflammation is an important factor in the pathogenesis of diabetic complication. Mycophenolate mofetil (MMF) has an anti-inflammatory effect, inhibiting lymphocyte proliferation. Previous studies showed attenuation of diabetic nephropathy with MMF, but the underlying mechanisms were unclear. This study aimed to identify the effect of MMF on diabetic nephropathy and investigate its action mechanisms in type 2 diabetic mice model. Eight-week-old db/db and control mice (db/m mice) received vehicle or MMF at a dose of 30 mg/kg/day for 12 weeks. MMF-treated diabetic mice showed decreased albuminuria, attenuated mesangial expansion, and profibrotic mRNA expressions despite the high glucose level. The number of infiltrated CD4⁺ and CD8⁺ T cells in the kidney was significantly decreased in MMF-treated db/db mice and it resulted in attenuating elevated intrarenal TNF-α and IL-17. The renal chemokines expression and macrophages infiltration were also attenuated by MMF treatment. The decreased expression of glomerular nephrin and WT1 was recovered with MMF treatment. MMF prevented the progression of diabetic nephropathy in db/db mice independent of glycemic control. These results suggest that the effects of MMF in diabetic nephropathy are mediated by CD4⁺ T cell regulation and related cytokines.

Cell Therapy Using Human Induced Pluripotent Stem Cell-Derived Renal Progenitors Ameliorates Acute Kidney Injury in Mice

Acute kidney injury (AKI) is defined as a rapid loss of renal function resulting from various etiologies, with a mortality rate exceeding 60% among intensive care patients. Because conventional treatments have failed to alleviate this condition, the development of regenerative therapies using human induced pluripotent stem cells (hiPSCs) presents a promising new therapeutic option for AKI. We describe our methodology for generating renal progenitors from hiPSCs that show potential in ameliorating AKI. We established a multistep differentiation protocol for inducing hiPSCs into OSR1+SIX2+ renal progenitors capable of reconstituting three-dimensional proximal renal tubule-like structures in vitro and in vivo. Moreover, we found that renal subcapsular transplantation of hiPSC-derived renal progenitors ameliorated the AKI in mice induced by ischemia/reperfusion injury, significantly suppressing the elevation of blood urea nitrogen and serum creatinine levels and attenuating histopathological changes, such as tubular necrosis, tubule dilatation with casts, and interstitial fibrosis. To our knowledge, few reports demonstrating the therapeutic efficacy of cell therapy with renal lineage cells generated from hiPSCs have been published. Our results suggest that regenerative medicine strategies for kidney diseases could be developed using hiPSC-derived renal cells.

SIGNIFICANCE

This report is the first to demonstrate that the transplantation of renal progenitor cells differentiated from human induced pluripotent stem (iPS) cells has therapeutic effectiveness in mouse models of acute kidney injury induced by ischemia/reperfusion injury. In addition, this report clearly demonstrates that the therapeutic benefits come from trophic effects by the renal progenitor cells, and it identifies the renoprotective factors secreted by the progenitors. The results of this study indicate the feasibility of developing regenerative medicine strategy using iPS cells against renal diseases.

The use of mycophenolate mofetil in experimental encapsulating peritoneal sclerosis

INTRODUCTION

Encapsulated peritoneal sclerosis (EPS) is a rare complication of long-term peritoneal dialysis usually associated with the inadequacy and early termination of dialysis modality. Adequate treatment of peritoneal fibrosis has not been achieved by medical intervention so far. Mycophenolate mofetil (MMF), which inhibits inosine monophosphate dehydrogenase reversibly and highly selectively, is the most widely used drug for maintenance immunosupression in renal transplantation. Recent studies have shown that MMF has also antifibrotic effects. In this study, we evaluated the effects of MMF on EPS model in rats based on antifibrotic effects.

MATERIALS AND METHODS

Twenty-four Wistar albino rat have been randomly divided into four groups. Group I (control group) received isotonic saline intraperitoneally (i.p) 2 ml/day for (0-3rd weeks). Group II (chlorhexidine (CG) group) received CG 2 ml/day i.p. for (0-3rd weeks). Group III (chlorhexidine + MMF group) received CG (2 ml/day) i.p. for (0-3rd weeks) plus MMF 30 mg/kg/day peroral (4th-6th weeks). Group IV (resting group) received CG 2 ml/day) i.p. (0-3rd weeks) plus peritoneal resting without any treatment (4th-6th weeks) At the end of the sixth weeks, all of the rats were killed. All of the groups were analyzed in terms of peritoneal thickness, degree of inflammation, vasculopathy, neovascularization and fibrosis. Also, the parietal peritoneal tissue samples were evaluated for matrix metalloproteinase 2 (MMP-2) by using the immunohistochemical analysis.

RESULTS

When the CG group was compared with the MMF group, the medication resulted in a statistically significant reduction in peritoneal thickness, inflammation and fibrosis score (53.23 ± 16.24 vs. 17.22 ± 3.62, 1 ± 1.225 vs. 1 ± 0, 1.6 ± 0.548 vs. 0.2 ± 0.447, respectively, all p < 0.05). In the resting group, no beneficial effects on morphological abnormality of the peritoneum were observed as compared with MMF group. However, according to immunohistochemical analysis of the expression of MMP-2 on peritoneal samples, the highest expression of MMP-2 was observed in the MMF group.

CONCLUSION

MMF was effective for the treatment of encapsulating peritoneal fibrosis in our rat model. Most recently, MMF may be first choice for EPS due to antifibrotic effect.

Qualitative analysis of the deposit of collagen in bladder suture of rats treated with tacrolimus combined with mycophenolate-mofetil

PURPOSE

To evaluate the synthesis of type I (mature) and type III (immature) collagen in bladder suture of rats treated with a combination of tacrolimus and mycophenolate mofetil for 15 days.

MATERIALS AND METHODS

Thirty rats were divided into 3 groups: the sham, control and experimental groups. All the animals underwent laparotomy, cystotomy and bladder suture in two planes with surgical PDS 5-0 thread. The sham group did not receive treatment. The control group received saline solution, and the experimental group received 0.1mg/kg/day of tacrolimus with 20mg/kg/day of mycophenolate mofetil, for 15 days. From then on, the tacrolimus was dosed. The surgical specimens of the bladder suture area were processed so that the total type I and type III collagen could be measured by the picrosirius red technique.

RESULTS

There was a predominance of type I collagen production in the sham and control groups compared to the experimental group, in which type III collagen was predominant. The production of total collagen did not change.

CONCLUSION

The association of tacrolimus and mycophenolate mofetil in animals qualitatively changes the production of collagen after 15 days with a predominance of type III collagen.

Effect of mycophenolate mofetil on progression of interstitial fibrosis and tubular atrophy after kidney transplantation: a retrospective study

OBJECTIVES

Chronic transplant dysfunction after kidney transplantation is a major reason of kidney graft loss and is caused by immunological and non-immunological factors. There is evidence that mycophenolate mofetil (MMF) may exert a positive effect on renal damage in addition to immunosuppression, by its direct antifibrotic properties. The aim of our study was to retrospectively investigate the role of MMF doses on progression of chronic allograft dysfunction and fibrosis and tubular atrophy (IF/TA).

SETTING

Retrospective, cohort study.

PARTICIPANTS

Patients with kidney transplant in a tertiary care institution. This is a retrospective cohort study that included 79 patients with kidney and kidney-pancreas transplantation. Immunosuppression consisted of anti-interleukin 2 antibody induction, MMF, a calcineurin inhibitor±steroids.

PRIMARY OUTCOME MEASURES

An association of average MMF doses over 1 year post-transplant with progression of interstitial fibrosis (Δci), tubular atrophy (Δct) and estimated-creatinine clearance (eCrcl) at 1 year post-transplant was evaluated using univariate and multivariate analyses.

RESULTS

A higher average MMF dose was significantly independently associated with better eCrcl at 1 year post-transplant (b=0.21±0.1, p=0.04). In multiple regression analysis lower Δci (b=-0.2±0.09, p=0.05) and Δct (b=-0.29±0.1, p=0.02) were independently associated with a greater average MMF dose. There was no correlation between average MMF doses and incidence of acute rejection (p=0.68).

CONCLUSIONS

A higher average MMF dose over 1 year is associated with better renal function and slower progression of IF/TA, at least partly independent of its immunosuppressive effects.

Activation of the miR-17 family and miR-21 during murine kidney ischemia-reperfusion injury

BACKGROUND

Ischemia-reperfusion (I/R) is the main cause of acute kidney injury (AKI) in patients. We investigated renal microRNA (miRNA) expression profiles and the time course of changes in selected miRNA expressions after renal I/R to characterize the miRNA network activated during development and recovery from AKI.

METHODS AND RESULTS

One day after lethal (30 minutes) and sublethal (20 minutes) renal ischemia, AKI was verified by renal histology (tubular necrosis, regeneration), blood urea nitrogen (BUN) level, renal mRNA expression, and plasma concentration of neutrophil gelatinase-associated lipocalin (NGAL) in C57BL/6J mice. On the first day after 30-minute, lethal I/R miR-21, miR-17-5p, and miR-106a were elevated out of the 21 miRNAs successfully profiled on the Luminex multiplex assay. After 20-minute, sublethal I/R, renal miR-17-5p and miR-106a expressions were elevated on the first and second days of reperfusion, while miR-21 expression increased later and lasted longer. Renal miR-17-5p and miR-21 expressions correlated with each other. Renal function returned to normal on the fourth day after sublethal I/R.

CONCLUSIONS

Our results demonstrate that besides miR-21, miR-17-5p, and miR-106a are additionally activated during the maintenance and recovery phases of renal I/R injury. Furthermore, a correlation between renal miR-17-5p and miR-21 expressions warrants further investigation of how they may influence each other and the outcome of renal ischemia-reperfusion injury.

Regulatory myeloid cells in transplantation

Regulatory myeloid cells (RMC) are emerging as novel targets for immunosuppressive (IS) agents and hold considerable promise as cellular therapeutic agents. Herein, we discuss the ability of regulatory macrophages, regulatory dendritic cells, and myeloid-derived suppressor cells to regulate alloimmunity, their potential as cellular therapeutic agents, and the IS agents that target their function. We consider protocols for the generation of RMC and the selection of donor- or recipient-derived cells for adoptive cell therapy. Additionally, the issues of cell trafficking and antigen (Ag) specificity after RMC transfer are discussed. Improved understanding of the immunobiology of these cells has increased the possibility of moving RMC into the clinic to reduce the burden of current IS agents and to promote Ag-specific tolerance. In the second half of this review, we discuss the influence of established and experimental IS agents on myeloid cell populations. IS agents believed historically to act primarily on T cell activation and proliferation are emerging as important regulators of RMC function. Better insights into the influence of IS agents on RMC will enhance our ability to develop cell therapy protocols to promote the function of these cells. Moreover, novel IS agents may be designed to target RMC in situ to promote Ag-specific immune regulation in transplantation and to usher in a new era of immune modulation exploiting cells of myeloid origin.

Chronic renal allograft damage after transplantation: what are the reasons, what can we do?

PURPOSE OF REVIEW

Chronic renal allograft damage is one of the main problems after kidney transplantation. This review enumerates causes, describes available therapeutic options, and discusses options of the future.

RECENT FINDINGS

Alloantigen-dependent and alloantigen-independent factors are responsible for allograft damage. Prevention of renal allograft damage starts with interventions that occur surrounding the explantation in cadaveric organs. These include the use of dopamine or machine perfusion systems.Followed by the critical phase of ischemia/reperfusion injury, the LCN2/lipocalin-2, HAVCR1, and p38 MAPK pathway are new players involved in that process. Innate immunity plays a part, too. Cold ischemia time is associated with genes of apoptosis. Nondonor-specific antibodies like antihuman leukocyte antibodies-Ia or angiotensin type 1 receptor may also play a role. Recent research indicates that genetic polymorphism like the Ficolin-2 Ala258Ser polymorphism and the mannose-binding lectin-2 polymorphism are involved in that process. New therapeutic options are rare and in the future. However, there is some evidence that drugs interfering with metalloproteinases, sexual hormones like dihydroandrosterone, and mesenchymal stem cell therapy may be of importance.

SUMMARY

Taken together, although the understanding of chronic rejection has improved, the available therapeutic options remain scarce.

Aryl hydrocarbon receptor agonist, leflunomide, protects the ischemic-reperfused kidney: role of Tregs and stem cells

The aryl hydrocarbon receptor (AHR) has emerged as a major modulator of inflammatory processes. We tested the hypothesis that AHR activation protects the ischemic-reperfused kidney in association with the suppression of the inflammatory response. Accordingly, male mice were treated with the nondioxin AHR agonist, leflunomide (40 mg/kg ip); vehicle-treated animals served as controls. Thereafter, the right kidney was subjected to an ischemia (45 min)-reperfusion (4 h) insult, while the left kidney served as a sham control. Renal cells prepared from ischemic-reperfused kidneys of leflunomide-treated mice displayed preservation of mitochondrial membrane potential (Ψ(m)) and decreased apoptosis and necrosis compared with vehicle-treated ischemic-reperfused kidneys. Leflunomide treatment increased regulatory T cells (Tregs; forkhead box P3+) and IL-10-positive cells but reduced IL-17- and IL-23-expressing cells in both the peripheral blood and kidney cells, indicative of down-regulation of inflammatory responses. Leflunomide treatment also increased mobilization of stems cells subsets (i.e., mesenchymal and hematopoietic stem cells and endothelial progenitor cells) in the peripheral blood and promoted their recruitment into the ischemic-reperfused kidney. Collectively, the results indicate that AHR stimulation may represent a novel renoprotective mechanism likely involving mobilization and recruitment of Tregs and stem cells into the damaged kidney.