Diabetes and Cardiovascular Risk in Renal Transplant Patients

Immune response against bacterial infection in organ transplant recipients

This comprehensive review delves into the intricate dynamics between the immune system and bacterial infections in organ transplant recipients. Its primary objective is to fill existing knowledge gaps while critically assessing the strengths and weaknesses of current research. The paper accentuates the delicate balance that must be struck between preventing graft rejection through immunosuppression and maintaining robust immunity against bacterial threats. In this context, personalized medicine emerges as a transformative concept, offering the potential to revolutionize clinical outcomes by tailoring immunosuppressive regimens and vaccination strategies to the unique profiles of transplant recipients. By emphasizing the pivotal role of continuous monitoring, the review underscores the necessity for vigilant surveillance of transplant recipients to detect bacterial infections and associated immune responses early, thereby reducing the risk of severe infections and ultimately improving patient outcomes. Furthermore, the study highlights the significance of the host microbiome in shaping immune responses, suggesting that interventions targeting the microbiome hold promise for enhancing bacterial immunity in transplant recipients, both in research and clinical practice. In terms of future research directions, the review advocates for large-scale, longitudinal studies encompassing diverse patient cohorts to provide more comprehensive insights into post-transplant immune responses. It also advocates integrating multi-omics approaches, including genomics, transcriptomics, proteomics, and microbiome data, to understand immune responses and their underlying mechanisms. In conclusion, this review significantly enriches our understanding of immune responses in transplant recipients. It paves the way for more effective and personalized approaches to managing infections in this complex setting.

Managing Post-Transplant Diabetes Mellitus after Kidney Transplantation: Challenges and Advances in Treatment

Kidney transplantation is the most effective treatment for end-stage renal failure but is associated with complications, including post-transplant diabetes mellitus (PTDM). It affects the quality of life and survival of patients and the transplanted organ. It can cause complications, including infections and episodes of acute rejection, further threatening graft survival. The prevalence of PTDM, depending on the source, can range from 4 to 30% in transplant patients. This article aims to discuss issues related to diabetes in kidney transplant patients and the latest treatments. Knowledge of the mechanisms of action of immunosuppressive drugs used after transplantation and their effect on carbohydrate metabolism is key to the rapid and effective detection of PTDM. Patient therapy should not only include standard management such as lifestyle modification, insulin therapy or pharmacotherapy based on well-known oral and injection drugs. New opportunities are offered by hypoglycemic drugs still in clinical trials, including glucokinase activators, such as dorzagliatin, ADV-1002401, LY2608204, TMG-123, imeglimine, amycretin and pramlintide. Although many therapeutic options are currently available, PTDM often creates uncertainty about the most appropriate treatment strategy. Therefore, more research is needed to individualize therapeutic plans and monitor these patients.

Comparison of Adverse Events Following Immunosuppressant Administration for Pediatric Patients With Renal Transplants Categorized by Two-Year Age Increments Using the U.S. Food and Drug Administration Adverse Event Reporting System

Background Immunosuppressants are frequently administered to prevent transplant rejection in patients with renal transplants but cause various adverse events. The incidence of each adverse event may differ between pediatric and adult patients with renal transplants. Because the development of organs and bodies in pediatric patients varies greatly annually, the incidence of each adverse event following immunosuppressant administration may vary by age. Consequently, the age-specific incidence of each adverse event in pediatric patients represents invaluable information for clinical settings. To clarify trends in the occurrence of adverse events by age, a large sample size for each age is required. However, it is difficult to conduct clinical trials in pediatric patients with renal transplants with a large sample size for each age. One method to address this difficulty is to use a database.  Objectives This study aimed to investigate the trends in the occurrence of each adverse event following immunosuppressant administration in pediatric patients with renal transplants, categorized by two-year age increments. Methods We extracted data on pediatric patients aged 0-17 years who received immunosuppressants after renal transplant between January 2004 and March 2024 from the U.S. Food and Drug Administration Adverse Event Reporting System. Because adverse events were greatly affected by age, the patients were divided into groups by two-year age increments. We analyzed the relationship between the groups and the reporting proportion of each adverse event by using the reporting regression coefficient (RRC) from univariate regression analysis and the adjusted RRC (aRRC), which controlled for differences in patient background. Results Renal tubular necrosis, renal impairment, chronic allograft nephropathy, and headache were the adverse events that required more attention with increasing age because RRC and aRRC were significantly > 0. By contrast, Epstein-Barr virus infection was the adverse event that required attention, especially in younger pediatric patients, because RRC and aRRC were significantly < 0. Additionally, there were various trends among other adverse events, including those that required careful monitoring across all ages 0-17 years. Conclusions This study demonstrated that the types of adverse events requiring attention in pediatric patients with renal transplants differ by age. These findings can help enhance treatment and care in pediatric clinical settings.

Prevalence of new-onset diabetes mellitus after kidney transplantation: a systematic review and meta-analysis

AIMS

Post-transplant diabetes is a prevalent and consequential complication following kidney transplantation, which significantly augments the risk of cardiovascular disease, graft loss, infection, and mortality, thereby profoundly impacting both graft and patient survival. However, the early stages of post-transplant diabetes often go unnoticed or receive inadequate management. Consequently, this study systematically assesses the incidence of new-onset diabetes after kidney transplantation with the aim to enhance medical staff awareness regarding post-transplantation diabetes and provide clinical management guidance.

METHODS

We conducted a comprehensive search across multiple databases including PubMed, Web of Science, Embase, The Cochrane Library, CNKI, Wanfang, VIP, and SinoMed until September 21, 2023. Data extraction was performed using standardized tables and meta-analysis was conducted using Stata 16.0 software. A random effects model was employed to estimate the combined prevalence along with its corresponding 95% confidence interval. The source of heterogeneity was explored using subgroup analysis and sensitivity analysis, while publication bias was assessed through funnel plot and Egger's test. This study has been registered with PROSPERO under the registration number CRD42023465768.

RESULTS

This meta-analysis comprised 39 studies with a total sample size of 16,584 patients. The prevalence of new-onset diabetes after transplantation was found to be 20% [95% CI (18.0, 22.0)]. Subgroup analyses were conducted based on age, gender, body mass index, family history of diabetes, type of kidney donor, immunosuppressive regimen, acute rejection episodes, hepatitis C infection status and cytomegalovirus infection.

CONCLUSIONS

The incidence of post-kidney transplantation diabetes is substantial, necessitating early implementation of preventive and control measures to mitigate its occurrence, enhance prognosis, and optimize patients' quality of life.

CLINICAL TRIAL REGISTRATION

PROSPERO: CRD42023465768.

Safety and efficacy of glucagon-like peptide-1 receptor agonists among kidney transplant recipients: a systematic review and meta-analysis

Background

Evidence supporting glucagon-like peptide-1 receptor agonists (GLP-1RAs) in kidney transplant recipients (KTRs) remains scarce. This systematic review and meta-analysis aims to evaluate the safety and efficacy of GLP-1RAs in this population.

Methods

A comprehensive literature search was conducted in the MEDLINE, Embase and Cochrane databases from inception through May 2023. Clinical trials and observational studies that reported on the safety or efficacy outcomes of GLP-1RAs in adult KTRs were included. Kidney graft function, glycaemic and metabolic parameters, weight, cardiovascular outcomes and adverse events were evaluated. Outcome measures used for analysis included pooled odds ratios (ORs) with 95% confidence intervals (CIs) for dichotomous outcomes and standardized mean difference (SMD) or mean difference (MD) with 95% CI for continuous outcomes. The protocol was registered in the International Prospective Register of Systematic Reviews (CRD 42023426190).

Results

Nine cohort studies with a total of 338 KTRs were included. The median follow-up was 12 months (interquartile range 6-23). While treatment with GLP-1RAs did not yield a significant change in estimated glomerular filtration rate [SMD -0.07 ml/min/1.73 m2 (95% CI -0.64-0.50)] or creatinine [SMD -0.08 mg/dl (95% CI -0.44-0.28)], they were associated with a significant decrease in urine protein:creatinine ratio [SMD -0.47 (95% CI -0.77 to -0.18)] and haemoglobin A1c levels [MD -0.85% (95% CI -1.41 to -0.28)]. Total daily insulin dose, weight and body mass index also decreased significantly. Tacrolimus levels remained stable [MD -0.43 ng/ml (95% CI -0.99 to 0.13)]. Side effects were primarily nausea and vomiting (17.6%), diarrhoea (7.6%) and injection site pain (5.4%).

Conclusions

GLP-1RAs are effective in reducing proteinuria, improving glycaemic control and supporting weight loss in KTRs, without altering tacrolimus levels. Gastrointestinal symptoms are the main side effects.

The pharmacogenetics of tacrolimus in renal transplant patients: association with tremors, new-onset diabetes and other clinical events

Our study is the first study to investigate the effect of SNPs in CYP3A5, CYP3A4, ABCB1 and POR genes on the incidence of tremors, nephrotoxicity, and diabetes mellitus. A total of 223 renal transplant patients receiving tacrolimus and mycophenolate mofetil (MMF) were recruited. Both adults and children patients participated in the study. Genotyping was performed using PROFLEX-PCR followed by RFLP. MPA and tacrolimus plasma concentrations were measured by immunoassay. The AUC0-12h of MMF was estimated by a Bayesian method. We found a statistically significant association between the CYP3A5*3 and CYP3A4*1B genotypes and the tacrolimus exposure. We found a lower occurrence of nephrotoxicity (p = 0.03), tremor (p = 0.01), and new-onset diabetes (p = 0.002) associated with CYP3A5*1 allele. The CYP3A4*1B allele was significantly associated with a lower occurrence of new-onset diabetes (p = 0.026). The CYP3A5*1 allele was significantly associated with an increased risk of acute and chronic rejection (p = 0.03 and p < 0.001, respectively). Our results support the usefulness of tacrolimus pharmacokinetics in pre-kidney transplant assessments.

Effectiveness and safety of immunosuppressive regimens used as maintenance therapy in kidney transplantation: The CESIT study

Maintenance immunosuppressive therapy used in kidney transplantation typically involves calcineurin inhibitors, such as tacrolimus or cyclosporine, in combination with mycophenolate or mechanistic target of rapamycin (mTORi) with or without corticosteroids. An Italian retrospective multicentre observational study was conducted to investigate the risk-benefit profile of different immunosuppressive regimens. We identified all subjects who underwent kidney transplant between 2009 and 2019, using healthcare claims data. Patients on cyclosporine and tacrolimus-based therapies were matched 1:1 based on propensity score, and effectiveness and safety outcomes were compared using Cox models (HR; 95%CI). Analyses were also conducted comparing mTORi versus mycophenolate among tacrolimus-treated patients. Patients treated with cyclosporine had a higher risk of rejection or graft loss (HR:1.69; 95%CI:1.16-2.46) and a higher incidence of severe infections (1.25;1.00-1.55), but a lower risk of diabetes (0.66;0.47-0.91) compared to those treated with tacrolimus. Among tacrolimus users, mTORi showed non-inferiority to MMF in terms of mortality (1.01;0.68-1.62), reject/graft loss (0.61;0.36-1.04) and severe infections (0.76;0.56-1.03). In a real-life setting, tacrolimus-based immunosuppressive therapy appeared to be superior to cyclosporine in reducing rejection and severe infections, albeit with an associated increased risk of diabetes. The combination of tacrolimus and mTORi may represent a valid alternative to the combination with mycophenolate, although further studies are needed to confirm this finding.

Impact of Type 2 Diabetes on the Outcomes of Solid Organ Transplantations in the U.S.: Data From a National Registry

OBJECTIVE

Type 2 diabetes (T2D) is a major driver of chronic diseases around the globe. The aim was to assess the impact of T2D on the outcomes of solid organ transplantations.

RESEARCH DESIGN AND METHODS

We used the Scientific Registry of Transplant Recipients from 2006 to 2021 to collect data for all patients age ≥18 years who received a lung, heart, liver, or kidney transplant in the U.S.

RESULTS

We included 462,692 solid organ transplant recipients: 31,503 lung, 38,004 heart, 106,639 liver, and 286,440 kidney transplantations. The prevalence of pretransplantation T2D was 15% in lung, 26% in heart, 25% in liver, and 30% in kidney transplant recipients, increasing over time. Posttransplantation mortality was significantly higher among transplant recipients with T2D versus those without T2D (lung 32.1% vs. 29.3% [3 years], 46.4% vs. 42.6% [5 years]; P < 0.01; heart 11.2% vs. 9.1% [1 year], 24.4% vs. 20.6% [5 years]; P < 0.0001; liver 10.6% vs. 8.9% [1 year], 26.2% vs. 22.0% [5 years]; P < 0.0001; kidney 5.3% vs. 2.5% [1 year], 20.8% vs. 10.1% [5 years]; P < 0.0001). Independent association of pretransplantation T2D with higher posttransplantation mortality was significant after adjustment for clinicodemographic confounders (adjusted hazard ratio in lung transplant recipients 1.08 [95% CI 1.03-1.13]; heart 1.26 [1.20-1.32]; liver 1.25 [1.21-1.28]; kidney 1.65 [1.62-1.68]; P < 0.01).

CONCLUSIONS

The prevalence of T2D in solid organ transplantation candidates is increasing. In all solid organ transplantations, pretransplantation T2D was independently associated with higher posttransplantation mortality, most profoundly in kidney transplantations.

Home-Based Exercise Training and Cardiac Autonomic Neuropathy in Kidney Transplant Recipients with Type-II Diabetes Mellitus

This randomized clinical trial aimed to examine the effects of a 6-month home-based, combined exercise training program on Cardiac Autonomic Neuropathy (CAN) in kidney transplant recipients (KTRs) with diabetes. Twenty-five KTRs (19 men (76.0%), with a mean age of 54.4 ± 11.3 years old, CAN and type II Diabetes Mellitus (DM-II)), were randomly assigned into two groups: A (n₁ = 13 KTRs), who underwent a home-based exercise training program for 6 months, and B (n₂ = 12 KTRs), who were assessed at the end of the study. A cardiopulmonary exercise testing (CPET), sit-to-stand test in 30 s (30-s STS), isokinetic muscle strength dynamometry, and 24-h electrocardiographic monitoring were applied to all participants, both at the baseline and at the end of the clinical trial. At first, there were no statistically significant differences between groups. After 6 months, group A showed higher values in exercise time by 8.7% (p = 0.02), VO₂peak by 7.3% (p < 0.05), 30-s STS by 12.0% (p < 0.05), upper limb strength by 46.1% (p < 0.05), and lower limb strength by 24.6% (p = 0.02), respectively, compared to the B group. Furthermore, inter-group changes at the end of the 6-month study indicated that group A statistically increased the standard deviation of R-R intervals (SDNN) by 30.3% (p = 0.01), root mean square of successive differences between normal heartbeats (rMSSD) by 32.0% (p = 0.03), number of pairs of successive NN (R-R) intervals that differ by more than 50 ms (pNN50) by 29.0% (p = 0.04), high frequency (HF (ms²)) by 21.6% (p < 0.05), HF (n.u.) by 48.5% (p = 0.01), and turbulence slope (TS) by 22.5% (p = 0.02), and decreased the low frequency (LF (ms²)) by 13.2% (p = 0.01), LF (n.u.) by 24.9% (p = 0.04), and LF/HF ratio by 24% (p = 0.01), compared to group B. Linear regression analysis after the 6-month study showed that there was a strong positive correlation between VO₂peak and SDNN (r = 0.701, p < 0.05) in group A. Moreover, multiple regression analysis showed that KTRs' participation in the exercise program showed favorable modifications to sympathovagal balance and aerobic capacity, as measured with SDNN and VO2peak, respectively. To summarize, diabetic KTRs' cardiac autonomic function and functional capacity can be improved after a home-based long-term exercise training program.

The Effect of Voriconazole on Tacrolimus in Kidney Transplantation Recipients: A Real-World Study

Tacrolimus is an immunosuppressant with a narrow therapeutic window. Tacrolimus exposure increased significantly during voriconazole co-therapy. The magnitude of this interaction is highly variable, but it is hard to predict quantitatively. We conducted a study on 91 kidney transplantation recipients with voriconazole co-therapy. Furthermore, 1701 tacrolimus concentration data were collected. Standard concentration adjusted by tacrolimus daily dose (C/D) and weight-adjusted standard concentration (CDW) increased to 6 times higher during voriconazole co-therapy. C/D and CDW increased with voriconazole concentration. Patients with the genotype of CYP3A5 *3/*3 and CYP2C19 *2/*2 or *2/*3 were more variable at the same voriconazole concentration level. The final prediction model could explain 54.27% of the variation in C/D and 51.11% of the variation in CDW. In conclusion, voriconazole was the main factor causing C/D and CDW variation, and the effect intensity should be quantitative by its concentration. Kidney transplant recipients with CYP3A5 genotype of *3/*3 and CYP2C19 genotype of *2/*2 and *2/*3 should be given more attention during voriconazole co-therapy. The prediction model established in this study may help to reduce the occurrence of rejection.

Metabolic and functional effects of exercise training in diabetic kidney transplant recipients

BACKGROUND

Physical activity levels are significantly lower in kidney transplant (KT) recipients compared to the general population. The effects of exercise training in KT recipients with diabetes mellitus remain unclear, and so little is known about the role of increased exercise on cardiovascular risk and metabolic profile of KT patients.

AIM

To investigate the effects of a 6-mo home-based exercise training program on functional capacity, glucose levels and lipid profile of diabetic KT patients.

METHODS

In total, 21 type II diabetic KT recipients were randomly assigned into two groups: Exercise (n = 11, aged 52.9 ± 10.1 years) and control (n = 10, aged 53.01 ± 9.5 years). All participants at baseline and the end of the study underwent biochemical tests for fasting plasma glucose levels, glycated hemoglobin and lipid profile and cardiopulmonary exercise testing for maximum oxygen uptake [(VO₂)_peak] estimation. The exercise group followed a 6-mo supervised home-based aerobic and progressive resistance exercise program of moderate intensity 3 times per week, while the control group continued to receive usual care.

RESULTS

At the end of the 6-mo study, the exercise group had significantly lower values in fasting plasma glucose by 13.4% (from 120.6 ± 28.9 mg/dL to 104.8 ± 21.9 mg/dL, P = 0.01), glycated hemoglobin by 1.5% (from 6.7% ± 0.4 to 6.6% ± 0.4, P = 0.01) and triglycerides by 8.5% (from 164.7 ± 14.8 mg/dL to 150.8 ± 11.6 mg/dL, P < 0.05) and higher values in high-density lipoprotein by 10.2% (from 51.4 ± 8.8 mg/dL to 57.2 ± 8.7 mg/dL, P < 0.05) and (VO₂)_peak by 4.7% (from 22.7 ± 3.3 to 23.8 ± 4.2, P = 0.02) than the control group. There were statistically significant differences between the two groups at the end of the study for fasting plasma glucose (decreased by 9.6%, P < 0.05), triglycerides (decreased by 4.5%, P = 0.04) and (VO₂)_peak (increased by 4.4%, P = 0.01). Finally, after training, there was a moderate, positive linear relationship between (VO₂)_peak and glycated hemoglobin in the exercise group (r = 0.408, P = 0.03).

CONCLUSION

The results demonstrated that a 6-mo home-based mixed type exercise training program can improve the functional capacity, levels of glucose and lipid profile of diabetic KT recipients.

Rho GTPases in kidney physiology and diseases

Rho family GTPases are molecular switches best known for their pivotal role in dynamic regulation of the actin cytoskeleton, but also of cellular morphology, motility, adhesion and proliferation. The prototypic members of this family (RhoA, Rac1 and Cdc42) also contribute to the normal kidney function and play important roles in the structure and function of various kidney cells including tubular epithelial cells, mesangial cells and podocytes. The kidney's vital filtration function depends on the structural integrity of the glomerulus, the proximal portion of the nephron. Within the glomerulus, the architecturally actin-based cytoskeleton podocyte forms the final cellular barrier to filtration. The glomerulus appears as a highly dynamic signalling hub that is capable of integrating intracellular cues from its individual structural components. Dynamic regulation of the podocyte cytoskeleton is required for efficient barrier function of the kidney. As master regulators of actin cytoskeletal dynamics, Rho GTPases are therefore of critical importance for sustained kidney barrier function. Dysregulated activities of the Rho GTPases and of their effectors are implicated in the pathogenesis of both hereditary and idiopathic forms of kidney diseases. Diabetic nephropathy is a progressive kidney disease that is caused by injury to kidney glomeruli. High glucose activates RhoA/Rho-kinase in mesangial cells, leading to excessive extracellular matrix production (glomerulosclerosis). This RhoA/Rho-kinase pathway also seems involved in the post-transplant hypertension frequently observed during treatment with calcineurin inhibitors, whereas Rac1 activation was observed in post-transplant ischaemic acute kidney injury.

Is Intestinal Dysbiosis-Associated With Immunosuppressive Therapy a Key Factor in the Pathophysiology of Post-Transplant Diabetes Mellitus?

Post-transplant diabetes mellitus (PTDM) is one of the most common and deleterious comorbidities after solid organ transplantation (SOT). Its incidence varies depending on the organs transplanted and can affect up to 40% of patients. Current research indicates that PTDM shares several common features with type 2 diabetes mellitus (T2DM) in non-transplant populations. However, the pathophysiology of PTDM is still poorly characterized. Therefore, ways should be sought to improve its diagnosis and therapeutic management. A clear correlation has been made between PTDM and the use of immunosuppressants. Moreover, immunosuppressants are known to induce gut microbiota alterations, also called intestinal dysbiosis. Whereas the role of intestinal dysbiosis in the development of T2DM has been well documented, little is known about its impacts on PTDM. Functional alterations associated with intestinal dysbiosis, especially defects in pathways generating physiologically active bacterial metabolites (e.g., short-chain fatty acids, trimethylamine N-oxide, indole and kynurenine) are known to favour several metabolic disorders. This publication aims at discussing the potential role of intestinal dysbiosis and dysregulation of bacterial metabolites associated with immunosuppressive therapy in the occurrence of PTDM.

Nursing Care for Kidney Transplant Patients: A Scoping Review

Objectives: Mapping nursing care in kidney transplant patients. Materials and method: A scoping review was conducted according to the recommendations of the Joanna Briggs Institute Reviewers’ Manual. Data were collected through 13 national and international databases from December 2020 to January 2021, following scientific rigor in the selection of the material. The pre-selection was made by reading the title, abstract and introductory text in advance; the materials included in this stage were read in full to define the content for the study. Results: Fifteen studies were included. Of these, 60% are articles; dissertations, manuals, protocols, guidelines and bulletins totaled 40% of the material studied. 86.6% of the material has a quantitative approach. Regarding the methodological design, 73.3% were descriptive/transversal character studies. Regarding the mapping of nursing care, it was possible to divide them into two categories: nursing care after kidney transplantation (immediate, mediated and late) and nursing care after kidney transplantation in primary health/extra-hospital care. Conclusions: It is concluded that the study allowed mapping nursing care to kidney transplant patients in the immediate, late and primary health care periods.

Tacrolimus inhibits insulin release and promotes apoptosis of Min6 cells through the inhibition of the PI3K/Akt/mTOR pathway

As a calcineurin inhibitor, tacrolimus is commonly used as a first‑line immunosuppressant in organ transplant recipients. Post‑transplantation diabetes mellitus (PTDM) is a common complication following kidney transplantation and is associated with immunosuppressant drugs, such as tacrolimus. PTDM caused by tacrolimus may be related to its influence on insulin secretion and insulin resistance. However, the specific mechanism has not been fully elucidated. The aim of the present study was to investigate whether the PI3K/Akt/mTOR signaling pathway served an important role in the pathogenesis of PTDM induced by tacrolimus. In the present study, the Cell Counting Kit‑8 assay was used to measure the effect of tacrolimus on the viability of Min6 mouse insulinoma cells. The effects of tacrolimus on the insulin secretion and the activity of caspase‑3 of Min6 cells stimulated by glucose exposure were measured by ELISA. Superoxide dismutase (SOD) and malondialdehyde (MDA) levels were measured using WST‑8 and thiobarbituric acid assays, respectively. The effects of tacrolimus on the mRNA expression levels of PI3K, Akt and mTOR were detected by reverse transcription‑quantitative PCR (RT‑qPCR), whereas the protein expression levels of PI3K, Akt, mTOR, phosphorylated (p)‑AKT and p‑mTOR in Min6 cells were assessed using western blotting. The present data indicated that, compared with the control group, 5, 25 and 50 ng/ml tacrolimus treatment could inhibit the insulin secretion of Min6 cells stimulated by glucose solution, and 50 ng/ml tacrolimus could notably decrease the stimulation index (P<0.05). Moreover, 50 ng/ml tacrolimus markedly increased the activity of caspase‑3 by 175.1% (P<0.05), it also decreased the SOD activity (P<0.01) and increased MDA levels (P<0.05). The RT‑qPCR results demonstrated that the mRNA expression levels of PI3K, Akt and mTOR were downregulated by 25 and 50 ng/ml tacrolimus (P<0.01). Furthermore, the western blotting results suggested that tacrolimus had no significant effects on the expression levels of total PI3K, Akt and mTOR proteins (P>0.05), but 25 and 50 ng/ml tacrolimus could significantly inhibit the expression levels of p‑Akt and p‑mTOR (P<0.01). In conclusion, tacrolimus decreased the activity and insulin secretion of pancreatic β cells and induced the apoptosis of islet β cells by inhibiting the mRNA expression levels of PI3K, Akt and mTOR and reducing the phosphorylation of Akt and mTOR proteins in the PI3K/Akt/mTOR signaling pathway, which may ultimately lead to the occurrence of diabetes mellitus, and may be considered as one of the specific mechanisms of PTDM caused by tacrolimus.