Tacrolimus trough level and oxidative stress in Tunisian kidney transplanted patients

BACKGROUND

The effect of tacrolimus (TAC) on oxidative stress after kidney transplantation (KT) is unclear. This study aimed to evaluate the influence of TAC trough levels of oxidative stress status in Tunisian KT patients during the post-transplantation period (PTP).

METHODS

A prospective study including 90 KT patients was performed. TAC whole-blood concentrations were measured by the microparticle enzyme immunoassay method and adjusted according to the target range. Plasma levels of oxidants (malondialdehyde (MDA) and advanced oxidation protein products (AOPP)) and antioxidants (ascorbic acid, glutathione (GSH), glutathione peroxidase (GPx), and superoxide dismutase (SOD)) were measured using spectrophotometry. The subjects were subdivided according to PTP into three groups: patients with early, intermediate, and late PT. According to the TAC level, they were subdivided into LL-TAC, NL-TAC, and HL-TAC groups.

RESULTS

A decrease in MDA levels, SOD activity, and an increase in GSH levels and GPx activity were observed in patients with late PT compared to those with early and intermediate PT (p < 0.05). Patients with LL-TAC had lower MDA levels and higher GSH levels and GPx activity compared with the NL-TAC and HL-TAC groups (p < 0.05).

CONCLUSION

Our results have shown that in KT patients, despite the recovery of kidney function, the TAC reduced but did not normalize oxidative stress levels in long-term therapy, and the TAC effect significantly depends on the concentration used.

Systemic oxidative stress may be associated with reduced IgG antibody titers against SARS-CoV-2 in vaccinated kidney transplant recipients: A post-hoc analysis of the RECOVAC-IR observational study

BACKGROUND

Coronavirus disease 2019 (COVID-19) poses an increased risk for severe illness and suboptimal vaccination responses in patients with kidney disease, in which oxidative stress may be involved. Oxidative stress can be reliably measured by determining circulating free thiols (R-SH, sulfhydryl groups), since R-SH are rapidly oxidized by reactive species. In this study, we aimed to examine the association between serum free thiols and the ability to mount a humoral immune response to SARS-CoV-2 vaccination in kidney patients.

METHODS

Serum free thiol concentrations were measured in patients with chronic kidney disease stages 4/5 (CKD G4/5) (n = 46), on dialysis (n = 43), kidney transplant recipients (KTR) (n = 73), and controls (n = 50). Baseline serum free thiol and interferon-γ-induced protein-10 (IP-10) - a biomarker of the interferon response - were analyzed for associations with seroconversion rates and SARS-CoV-2 spike (S1)-specific IgG concentrations after two doses of the mRNA-1273 vaccine.

RESULTS

Albumin-adjusted serum free thiol concentrations were significantly lower in patients with CKD G4/5 (P < 0.001), on dialysis (P < 0.001), and KTR (P < 0.001), as compared to controls. Seroconversion rates after full vaccination were markedly reduced in KTR (52.1%) and were significantly associated with albumin-adjusted free thiols (OR = 1.76, P = 0.033). After adjustment for MMF use, hemoglobin, and eGFR, this significance was not sustained (OR = 1.49, P = 0.241).

CONCLUSIONS

KTR show suboptimal serological responses to SARS-CoV-2 vaccination, which is inversely associated with serum R-SH, reflecting systemic oxidative stress. Albeit this association was not robust to relevant confounding factors, it may at least partially be involved in the inability of KTR to generate a positive serological response after SARS-CoV-2 vaccination.

Neurologic outcome following liver transplantation for methylmalonic aciduria

Liver and liver/kidney transplantation are increasingly used in methylmalonic aciduria, but little is known on their impact on CNS. The effect of transplantation on neurological outcome was prospectively assessed in six patients pre- and post-transplant by clinical evaluation and by measuring disease biomarkers in plasma and CSF, in combination with psychometric tests and brain MRI studies. Primary (methylmalonic- and methylcitric acid) and secondary biomarkers (glycine and glutamine) significantly improved in plasma, while they remained unchanged in CSF. Differently, biomarkers of mitochondrial dysfunction (lactate, alanine, and related ratios) significantly decreased in CSF. Neurocognitive evaluation documented significant higher post-transplant developmental/cognitive scores and maturation of executive functions corresponding to improvement of brain atrophy, cortical thickness, and white matter maturation indexes at MRI. Three patients presented post-transplantation reversible neurological events, which were differentiated, by means of biochemical and neuroradiological evaluations, into calcineurin inhibitor-induced neurotoxicity and metabolic stroke-like episode. Our study shows that transplantation has a beneficial impact on neurological outcome in methylmalonic aciduria. Early transplantation is recommended due to the high risk of long-term complications, high disease burden, and low quality of life.

Child Neurology: Neurodegenerative Encephalomyelopathy Associated With ACOX-1 Gain-of-Function Mutation Partially Responsive to Immunotherapy

Acyl-CoA Oxidase 1 (ACOX1) is a peroxisomal enzyme involved in beta-oxidation of very long chain fatty acids. Although loss of function of ACOX-1 had been previously described, gain-of-function mutation of ACOX-1 gene has only been recently identified, with a paucity of known cases. Gain of function mutation results in over production of reactive oxygen species, resulting in progressive neurodegeneration with discrete relapses.We report a 19-year-old-female with a 5-year history of longitudinally extensive posterior predominant myelopathy, bilateral corneal scars, and white matter lesions presented with first time seizure, progressive sensorineural hearing loss, icthiosyform rash, and cauda equina syndrome. Extensive work-up was unrevealing. The patient had no response to high dose steroids but stabilization and improvement with return to baseline over six months with IVIg and low dose mycophenolate mofetil. WES performed 4 years prior was non-diagnostic, but subsequent reanalysis revealed a heterozygous mutation in the ACOX1 gene (NM_004035.6: c.710A>G, p.Asn237Ser), now considered to be pathogenic.This case reports a rare condition and highlights the importance of reanalysis of previously non-diagnostic genome/exome sequencing data. Further, the patient's clinical stability for over one year on immunotherapy raises the possibility of disease modification in an otherwise universally fatal condition.

Study on alleviate effect of Wuzhi capsule (Schisandra sphenanthera Rehder & E.H. Wilson extract) against mycophenolate mofetil-induced intestinal injury

ETHNOPHARMACOLOGICAL RELEVANCE

Schisandra sphenanthera Rehder & E.H. Wilson (S. sphenanthera) is a botanical medicine included in the 2020 edition of the ChP that has a variety of medicinal activities, including hepatoprotective, anticancer, antioxidant and anti-inflammatory properties. Wuzhi capsule (WZ) is a proprietary Chinese medicine made from an ethanolic extract of S. sphenanthera that is commonly used to treat drug-induced liver injury. However, there are no research reports exploring the effects of WZ on the prevention of mycophenolate mofetil (MMF)-induced intestinal injury and its underlying mechanisms.

AIM OF THE STUDY

This experiment aimed to evaluate the ameliorative effect of WZ on MMF-induced intestinal injury in mice and its underlying mechanisms.

MATERIALS AND METHODS

A mouse model of MMF-induced intestinal injury was established and treated with WZ during the 21-day experimental period. The pathological characteristics of the mouse ileum were observed. Tight junction (TJ) protein changes were observed after immunofluorescence staining and transmission electron microscopy, and ROS levels were measured by using DHE fluorescent dye and the TUNEL assay for apoptosis. The expression of p65, p-p65, IκBα, p-IκBα, the TJ proteins occludin and ZO-1 and the apoptosis-related proteins Bax, Bcl-2, cleaved caspase-3 and caspase-3 were analysed by Western blot. Levels of DAO, ET, TNF-α, IL-1β, IL-6, IFN-γ, MDA and SOD were analysed by using kits.

RESULTS

MMF activated the NF-κB signaling pathway to cause intestinal inflammation, increased intestinal permeability, changed the expression of TJ protein in the intestinal epithelium, and increased oxidative stress and apoptosis levels. WZ significantly downregulated the expression of p-p65 and p-IκBα to relieve the inflammatory response, reduced intestinal permeability, maintained intestinal TJ protein expression, and reduced intestinal oxidative stress and apoptosis.

CONCLUSION

Our research suggested that MMF can cause intestinal injury; by contrast, WZ may exert anti-inflammatory, antioxidant and apoptosis-reducing effects to alleviate MMF-induced intestinal injury.

Schisandrin A alleviates mycophenolic acid-induced intestinal toxicity by regulating cell apoptosis and oxidative damage

The gastrointestinal side effects of mycophenolic acid affect its efficacy in kidney transplant patients, which may be due to its toxicity to the intestinal epithelial mechanical barrier, including intestinal epithelial cell apoptosis and destruction of tight junctions. The toxicity mechanism of mycophenolic acid is related to oxidative stress-mediated the activation of mitogen-activated protein kinases (MAPK). Schisandrin A (Sch A), one of the main active components of the Schisandra chinensis, can protects intestinal epithelial cells from deoxynivalenol-induced cytotoxicity and oxidative damage by antioxidant effects. The aim of this study was to investigate the protective effect and potential mechanism of Sch A on mycophenolic acid-induced damage in intestinal epithelial cell. The results showed that Sch A significantly reversed the mycophenolic acid-induced cell viability reduction, restored the expression of tight junction protein ZO-1, occludin and reduced cell apoptosis. In addition, Sch A inhibited mycophenolic acid-mediated MAPK activation and reactive oxygen species (ROS) increase. Collectively, our study showed that Sch A protected intestinal epithelial cells from mycophenolic acid intestinal toxicity, at least in part, by reducing oxidative stress and inhibiting MAPK signaling pathway.

Protective effects of selenium in tacrolimus-induced lung toxicity: potential role of heme oxygenase 1

The present study aimed to evaluate the protective effects of selenium (Sel) administration against tacrolimus (Tac) - induced lung toxicity and to assess the relation between heme oxygenase 1 (HO-1) and these effects. The study was conducted on 36 Wistar male albino rats equally divided into four groups: (i) normal control; (ii) Sel (0.1 mg/kg per day p.o. for four weeks); (iii) TAC 3 mg/mL as single oral dose on 27th day; and (iv) Tac + Sel. Lung tissues, lung homogenate, and bronchoalveolar lavage of the sacrificed animals were investigated biochemically and histopathologically, by immunohistochemistry or by PCR. The Tac group showed significantly lower expression of HO-1. Administration of Sel was associated with increased HO-1 expression. Oxidative (malondialdehyde, reduced glutathione, superoxide dismutase, myeloperoxidase, and glutathione peroxidase activity) and nitrosative stress (nitric oxide) markers and markers of inflammation (interleukin 1β (IL-1β), IL-6, and IL-10) showed changes corresponding to HO-1 levels in rat groups. Tac group showed the highest expression of caspase-3. Sel exerted a protective role against Tac-induced lung toxicity.

Tacrolimus ameliorates tubulointerstitial inflammation in diabetic nephropathy via inhibiting the NFATc1/TRPC6 pathway

Tubulointerstitial inflammation is crucial for the progression of diabetic nephropathy (DN), and tubular cells act as a driving force in the inflammatory cascade. Emerging data suggested that tacrolimus (TAC) ameliorates podocyte injury and macrophage infiltration in streptozotocin (STZ) mice. However, the effect of TAC on tubulointerstitial inflammation remains unknown. We found that albuminuria and tubulointerstitial damage improved in db/db mice treated with TAC. Macrophage infiltration and expression of IL‐6, TNF‐α, fibronectin, collagen 1 and cleaved caspase 3 were inhibited as well. In addition, the expression of nuclear factor of activated T cell 1 (NFATc1) and transient receptor potential channel 6 (TRPC6) was up‐regulated in the kidneys of DN patients and correlated with tubular injury and inflammation. The expression of NFATc1 and TRPC6 also increased in the kidneys of db/db mice and HK‐2 cells with high glucose (HG), while TAC inhibited these effects. HG‐induced inflammatory markers and apoptosis were reversed by TAC and NFATc1 siRNA in HK‐2 cells, which was abolished by TRPC6 plasmid. Furthermore, HG‐induced TRPC6 expression was inhibited by NFATc1 siRNA, while NFATc1 nuclear translocation was inhibited by TAC, but was restored by TRPC6 plasmid in HK‐2 cells under HG conditions. These findings suggest that TAC ameliorates tubulointerstitial inflammation in DN through NFATc1/TRPC6 feedback loop.

Effect of ultraviolet irradiation on free radical scavenging activity of immunosuppressants used in lung transplantation and comparative electron paramagnetic resonance study of kinetics of their interactions with model free radicals

WHAT IS KNOWN AND OBJECTIVE

The immunosuppressive drugs used in solid organ transplantation or autoimmunological processes were studied by electron paramagnetic resonance (EPR) spectroscopy to estimate their free radical scavenging activity. The interactions of immunosuppressants with free radicals were examined by an X-band (9.3 GHz) EPR spectroscopy and a model of DPPH free radicals.

METHODS

The EPR spectra of DPPH and DPPH interacting with individual drugs were compared. Kinetic studies were performed, and the effect of ultraviolet (UV) irradiation on the free radical scavenging activity of the tested drugs was determined.

RESULTS AND DISCUSSION

The free radical scavenging activity of non-irradiated drugs decreased in the order: rapamycin > mycophenolate mofetil > ciclosporin > tacrolimus. UV irradiation increased the free radical scavenging activity of all the tested immunosuppressive drugs, and the effect was highest for tacrolimus. For the non-irradiated samples, the speed of free radical interactions decreased in the order: ciclosporin > tacrolimus > mycophenolate mofetil > rapamycin. UV irradiation only slightly affected the speed of interactions of the immunosuppressive drugs with the model DPPH free radicals.

WHAT IS NEW AND CONCLUSION

Electron paramagnetic resonance spectroscopy is useful for obtaining information on interactions of immunosuppressive drugs with free radicals. We hypothesized that the long-term immunosuppressive effects of these drugs after transplantation or during autoimmune disorders may be mediated by anti-inflammatory action in addition to the known receptor/cell cycle inhibition.

DNA damage in kidney transplant patients. Role of organ origin

Chronic kidney disease (CKD) patients are characterized by elevated levels of genomic damage. This damage increases when kidney function decreases being maximum in hemodialysis patients. As kidney transplantation improves renal function, and it is related with better survival, the aim of our study was to evaluate potential changes in DNA damage levels after kidney transplantation, and comparing living donor recipients with cadaveric donor recipients. The alkaline comet assay was used to determine DNA breaks and oxidative damaged DNA; and the micronucleus assay was used to determine chromosomal breakage and/or aneuploidy. Fifty CKD patients were followed up after 6 and 12 months of their kidney transplantation. All patients increased their genomic damage levels after 6 and 12 months of renal transplantation, compared with those observed before transplantation, despite of the improvement of their metabolic functions. Donor advanced age correlated positively with higher DNA damage. Genomic damage was lower in living donor transplants with respect to cadaveric donor transplants. Our conclusion is that DNA damage increased in kidney transplantation patients, whereas their renal function improved. Higher levels of DNA damage were found in cadaveric donor transplants when compared to living donor transplants. Environ. Mol. Mutagen. 58:712-718, 2017. © 2017 Wiley Periodicals, Inc.

Antagonistic Effect of Oxytocin and Tacrolimus Combination on Adipose Tissue - Derived Mesenchymal Stem Cells: Antagonistic effect of oxytocin and tacrolimus

Tacrolimus (FK506) is a chemotherapeutic agent, which uses calcineurin pathway via inhibiting the stimulation of T cells to prevent the formation of immune response in the recipient individual in organ transplants. FK506 is mainly metabolized in the liver by cytochrome P450 enzyme system and is known that it has high toxic effects on different cells. Mesenchymal stem cells (MSCs) have recently gained importance since their potential to be used in cellular therapy and tissue regeneration. In some clinical cases, MSCs are transferred into the patient after the organ transplantations in order to support the treatment. Because of their immunomodulatory actions and assistance to the regeneration, popularity of MSCs have been increasing recently. However, since immunosuppressive agents have a potential cytotoxic and apoptotic effect on MSCs, researches have attempted to use it as a combination with an agent that alleviates these effects. Oxytocin (OT) is primarily acting as a neuromodulator in humans and is a peptide hormone secreted by the pituitary gland of the neurohypophysis. OT has such effects on cells as to confer resistance against oxidative stress on cells and to increase the proliferation and help regeneration. Studies on the active substance of FK506 were aimed to investigate the cytotoxic effects on human adipose tissue derived MSCs. The purpose of this study was to determine the cytotoxic, apoptotic and morphological effects of FK506, an immunosuppressive agent, on adipose tissue - derived MSC (ADMSC) which has the potential to be used for immune suppression. In addition, it was aimed to determine whether the agent could reduce the cytotoxic, apoptotic, and morphological effects on ADMSCs when used in combination with OT. For this purpose, the cytotoxic effects of the FK506 and OT on ADMSCs were determined by time and dose dependent manner by the WST-1 test. Isobologram analysis was evaluated using the WST-1 test according to IC₅₀ values of FK506 and OT. The apoptotic effects of the agents on the ADMSCs were determined by the Annexin V method. Immunofluorescence staining was performed to determine morphological changes. Changes in the levels of oxidative stress markers were measured by colorimetric and flourometric methods using lipid peroxidation, superoxide dismutase activity, catalase activity and glutathione peroxidase assays. The IC₅₀ values of FK506 and OT on ADMSCs were calculated as 17.44μM and 13.43μM, respectively.FK506 and OT were found to have antagonistic activity on ADMSCs (CI value of the combination was 1.24). The effects of the agents individually and in combination on the levels of apoptosis and oxidative stress markers have been evaluated. When the results obtained from the study are evaluated, the adipose- tissue derived mesenchymal stem cells used with takrolimus and oxytocin combination have a potential for novel treatment approaches.

Protective effect of mycophenolate mofetil against nephrotoxicity and hepatotoxicity induced by tacrolimus in Wistar rats

Tacrolimus (TAC), a calcineurin inhibitor (CNI), is clinically used as an immunosuppressive agent in the transplant recipient; however, the use of TAC is greatly limited by its nephrotoxicity and hepatotoxicity. Mycophenolate mofetil (MMF), an inhibitor of the purine synthesis, has been used in combination with many immunosuppressive drugs such as TAC. The association TAC/MMF was used in organ transplantation to increase the efficiency and reduce acute rejection rates, but the effects of MMF on TAC-induced kidney and liver injuries are still not well investigated. The aims of this study are to explore whether MMF co-administration with TAC has a renoprotective and hepatoprotective effect against TAC-induced renal and hepatic injuries and to check the implication of oxidative stress in the MMF's possible protective effect. Our results showed that MMF (at 50 mg kg(-1) body weight (b.w.)) restored creatinine, in addition to increased AST and ALT levels by TAC (at 60 mg kg(-1) b.w.). Furthermore, MMF decreased DNA damage induced by TAC in the kidney and liver of rats as assessed by comet assay. This renoprotective and hepatoprotective effect of MMF was associated with an antioxidant effect. In fact, MMF co-treatment with TAC decreased oxidative damage induced by TAC. It reduced malondialdehyde (MDA) and protein carbonyl (PC) levels as well as catalase and superoxide dismutase (SOD) activities. We conclude that the co-administration MMF with TAC protect liver and kidney against TAC toxicity via an antioxidant process.