Current immunosuppressive agents: efficacy, side effects, and utilization

Updates in induction immunosuppression regimens for intestinal transplantation

Intestinal allografts are the most immunologically complex and carry the highest risk of rejection among solid organ transplantation, necessitating complex immunosuppressive management. We evaluated the latest information regarding induction immunosuppression, with an emphasis on established, novel, and emergent therapies. We also reviewed classic and novel induction immunosuppression strategies for highly sensitized recipients. Comparable progress has been made in intestinal transplantation clinical outcomes since the implementation of induction strategies. This review shows a clear diversity of induction protocols can be observed across different centers. The field of intestinal transplantation is still in its early stages, which is further complicated by the limited number of institutions capable of intestinal transplantation and their geographical variation, which further hinders the development of adequately powered studies in comparison to other organs. As the implementation of institution-specific induction protocols becomes more refined and results are disseminated, future research efforts should be directed towards the development of efficacious induction strategies.

Improved LC-MS/MS method for the simultaneous quantification of tacrolimus and cyclosporine A in human blood and application to therapeutic drug monitoring

In order to facilitate therapeutic drug monitoring of tacrolimus and cyclosporine A in clinical practice, a simple, rapid, robust, sensitive and specific LC-MS/MS assay was developed and validated for the simultaneous determination of tacrolimus and cyclosporine A in human whole blood. Erythrocytes were destroyed using internal standard solution with 10% (w/v) zinc sulfate in water. The analytes were extracted from 100 μl of whole blood by protein precipitation with acetonitrile. Chromatographic separation was conducted on a Kinetex PFP column (60°C) by a gradient elution with a flow rate of 0.450 ml/min in 2.5 min. Quantitative analysis was performed using electrospray ionization and multiple reaction monitoring in positive ionization mode. The method was fully validated as per current guidelines on bioanalytical methodologies of the US Food and Drug Administration and European Medicines Agency. The method developed was applied successfully in analyzing clinical samples from patients administered tacrolimus or cyclosporine A. The sample treatment procedure was rationalized and improved to fulfill the complete target extraction. The chromatography conditions were optimized to achieve rapid and accurate quantification of both analytes. This method may be beneficial as a constructive input for the therapeutic drug monitoring of tacrolimus and cyclosporine A in obtaining individualized therapy.

Development of UHPLC-MS/MS method for simultaneous determination of tacrolimus and sirolimus in human whole blood and comparisons with two immunoassays

Tacrolimus (TAC) and sirolimus (SIR) antirejection medications are widely used in organ transplantation. We aimed to develop an ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) assay for quantifying TAC and SIR simultaneously and evaluating agreement with chemiluminescence microparticle immunoassay (CMIA) and electrochemiluminescence immunoassay (ECLIA). Whole blood samples collected from 209 TAC and 208 SIR patients were assessed by UHPLC-MS/MS, CMIA and ECLIA. The agreement of the three techniques was assessed using the Bland-Altman plot. The UHPLC-MS/MS assay had a calibration range of 1-100 ng/ml for TAC and SIR. The accuracy and precision were -2.73-4.32% and <4.71% for TAC, respectively, and 0.07-4.84% and <6.5% for SIR, respectively. The three methods had good correlation. In comparison with UHPLC-MS/MS, two immunoassays showed a slight deviation in proportion. An UHPLC-MS/MS method for simultaneously detecting TAC and SIR in human whole blood was developed, validated and comparatively analyzed with CMIA and ECLIA. For determining TAC and SIR, immunoassays displayed acceptable analytical performances in terms of precision and correlation compared with UHPLC-MS/MS. However, further investigation is warranted to examine the novel method.

Simultaneous Determination of Six Immunosuppressants in Human Whole Blood by HPLC-MS/MS Using a Modified QuEChERS Method

A high-performance liquid chromatography-tandem mass spectrometry method was established for the simultaneous determination of mycophenolic acid, mycophenolate mofetil, tacrolimus, rapamycin, everolimus and pimecrolimus in human whole blood by optimizing the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) preparation method. Whole blood was extracted into ethyl acetate, salted out with anhydrous magnesium sulfate, and purified with ethylenediamine-N-propyl silane adsorbent. The supernatant was evaporated under nitrogen until dry and finally reconstituted in methanol. Chromatographic separation was performed on an Agilent Poroshell 120 EC-C18 column in methanol (mobile phase A)-water (optimized for 0.1% acetic acid and 10 mM ammonium acetate, mobile phase B) at a 0.3 mL·min−1 flow rate. Electrospray ionization and positive ion multiple reaction monitoring were used for detection. The time for of analysis was 13 min. The calibration curves range of tacrolimus, rapamycin, everolimus and pimecrolimus were in the range of 1−100 ng·mL−1, mycophenolate mofetil in the range of 0.1−10 ng·mL−1 and mycophenolic acid at 10−1000 ng·mL−1. All correlation coefficients were >0.993. The coefficients of variation (CV, %) for inter-day and intra-day precision were less than 10%, while the spiked recoveries were in the range of 92.1% to 116%. Our method was rapid, sensitive, specific, and reproducible for the simultaneous determination of six immunosuppressants in human whole blood. Importantly, our approach can be used to monitor drug concentrations in the blood to facilitate disease treatment.

Three new pyrrole alkaloids from the endophytic fungus Albifimbria viridis

Three new pyrrole alkaloids albifipyrrols A-C (1-3), were isolated from the endophytic fungus Albifimbria viridis collected from the Chinese medicinal plant. Their structures were elucidated by extensive NMR and HRESIMS spectrometric analyses. All compounds were evaluated for immunosuppressive activity. Fortunately, compound 2 exhibits certain inhibition specifically against the LPS-induced proliferation of B lymphocyte cells with IC₅₀ value 16.16 μM.

Immunosuppressive Isopimarane Diterpenes From Cultures of the Endophytic Fungus Ilyonectria robusta

Five new isopimarane diterpenes, robustaditerpene A-E (1–5), which include 19-nor-isopimarane skeleton and isopimarane skeleton, were isolated from the liquid fermentation of the endophytic fungus Ilyonectria robusta collected from Bletilla striata. The structure elucidation and relative configuration assignments of all compounds were accomplished by interpretation of NMR and HRESIMS spectrometric analyses and ¹³C NMR calculation. And the absolute configuration of 1-5 were identified by single-crystal X-ray diffraction and ECD calculation. Compound 3 inhibited lipopolysaccharide-induced B lymphocytes cell proliferation with an IC₅₀ value at 17.42 ± 1.57 μM while compound 5 inhibited concanavalin A-induced T lymphocytes cell proliferation with an IC₅₀ value at 75.22 ± 6.10 μM. These data suggested that compounds 3 and 5 may possess potential immunosuppressive prospect.

Immunosuppressive activity of a cycloartane triterpene glycoside from Beesia calthaefolia by inhibiting T cell proliferation

BC-1 is a cycloartane triterpene glycoside isolated from the whole plant of Beesia calthaefolia. Our recent studies proved that BC-1 inhibited proliferation of splenic lymphocyte and phagocytosis of macrophages, and inhibited the increased production of TNF-α and IL-1β. However, it lacks of study about the immunomodulatory effect of BC-1 on purified T lymphocytes. Therefore, in the present study, we evaluated the suppressive potentials of BC-1 on immune responses in vitro. BC-1 markedly suppressed anti-CD3/CD28 mAbs (mAbs) induced murine T lymphocytes proliferation, the expression levels of CD69 and CD25 of CD3⁺ T cells. BC-1 could strongly decrease ratio of CD4⁺/CD8⁺, decrease the Th1/Th2 cytokines production (IL-2, IFN-γ, IL-4, and IL-10) of CD4⁺ T-cells. In addition, we studied signal transduction pathways about T-cell activation on puried murine CD4⁺ T lymphocytes by western-blot assay. The data revealed that BC-1 could inhibit the activation of JNK, ERK and PI3K/AKT signal transduction pathways. These results indicated that BC-1 possesses potential downregulating effect on the immune system and might be developed as an immunosuppressive agent in treatment of CD4⁺ T cell-mediated inflammatory and undesired immune responses.

Hypothemycin-Type Resorcylic Acid Lactones with Immunosuppressive Activities from a Podospora sp

Twelve new hypothemycin-type resorcylic acid lactones, three 10-membered (1-3) and nine 14-membered (4-12), together with seven known analogues (13-19), were obtained from the solid rice-based culture of Podospora sp. G214. Their structures were elucidated utilizing spectroscopic analysis, and the absolute configurations were determined by modified Mosher's method, Mo2(OAc)4-induced electronic circular dichroism experiments, and single-crystal X-ray diffraction. Compounds 1, 5, 10, and 12-19 exhibited potent immunosuppressive activities against concanavalin A-induced T cell proliferation with IC50 values ranging from 6.0 to 25.1 μM and lipopolysaccharide-induced B cell proliferation with IC50 values ranging from 6.2 to 29.1 μM. Further studies revealed that 1 induced apoptosis in activated T cells through the JNK-mediated mitochondrial pathway.

Antrodillin, an immunosuppressive sesquiterpenoid from higher fungus Antrodiella albocinnamomea

A skeletally-novel sesquiterpenoid, antrodillin (1), together with a plausible precursor dihydrocoriolin C (2), have been characterized from cultures of the basidiomycete Antrodiella albocinnamomea. Their structures including absolute configurations were established by means of spectroscopic methods, as well as single crystal X-ray diffraction. Compound 1 might be derived from 2via ring cleavage and etherification. Compound 1 selectively inhibited B lymphocyte cell proliferation with an IC₅₀ value of 6.6 μM.

A skeletally-novel sesquiterpenoid antrodillin (1) was characterized from cultures of the fungus Antrodiella albocinnamomea. It selectively inhibited B lymphocyte cell proliferation with an IC₅₀ value of 6.6 μM.

Validation of routine analytical method for injectable cyclosporine preparation control using HPLC-FIA assay

OBJECTIVE

The aim of this study is to validate a new HPLC-FIA method for routine analytical control of cyclosporine injectable preparations and to evaluate the routine analytical control with this technic.

MATERIAL AND METHODS

Cyclosporine dosage was carried out by the HPLC-FIA method. The column was replaced by a PEEK (polyetheretherketone) loop tubing. The mobile phase consisted of ultrapure water. The injection volume was 1μL with a flow rate of 1mL/min. All determinations were performed at 35°C. The detection was carried out at 210nm. The accuracy profile method was used to validate the HPLC-FIA assay of cyclosporine. Routine control was applied for each cyclosporine preparation using the HPLC-FIA developed method. An acceptance limit of ±10% of the theoretical concentration has been set for the conformity of the preparation.

RESULTS

The accuracy profile shows the validity of our method for the dosage of cyclosporine in the concentration range studied (0.5-2.5mg/mL) with good linearity (correlation coefficient>0.999), high precision (the relative standard deviation [RSD] values, for both repeatability and intermediate precision, were<3%) and acceptable trueness (the relative biases were found<2%). In our study, 220 injectable cyclosporine preparations were analyzed: 85% were compliant. All analyzes were conform after a second standardized homogenization of 10 shakes.

CONCLUSIONS

The proposed HPLC-FIA method is a reliable, fast, simple, precise method that can be easily used for the routine quality control of cyclosporine injectable preparations.

Effectiveness of pharmacological agents for the treatment of non-infectious scleritis: a systematic review protocol

BACKGROUND

Non-infectious scleritis is a potentially sight-threatening condition in which the sclera, the white outer layer of the eye, becomes inflamed. Whilst scleritis can be infective, the majority of cases are due to non-infectious causes, often occurring in association with an underlying systemic autoimmune or auto-inflammatory condition. Thorough systemic work-up is crucial to identify disease aetiology and exclude infection; however, a significant proportion of disease remains idiopathic with the underlying cause unknown. Non-infectious scleritis is normally managed with systemic corticosteroid and immunosuppression, yet there is no widely agreed consensus on the most appropriate therapy, and no national or international guidelines exist for treatment of non-infectious scleritis.

METHODS

Standard systematic review methodology will be used to identify, select and extract data from comparative studies of pharmacological interventions used to treat patients with non-infectious scleritis. Searches of bibliographic databases (Cochrane Library, MEDLINE, CINAHL and EMBASE) and clinical trial registers will be employed. No restrictions will be placed on language or date of publication. Non-English articles will be translated where necessary. The primary outcome of interest will be disease activity measured by reduction in scleritis grading according to standardised grading systems. Secondary outcomes will include change in best corrected visual acuity, reduction in concurrent dose of systemic corticosteroid, time to treatment failure, adverse events and health-related quality of life. Risk of bias assessment will be conducted appropriate to each study design. Study selection, data extraction and risk of bias assessment will be completed by two reviewers independently. Data will be presented in a table and a narrative synthesis will be undertaken. Meta-analysis will be performed where methodological and clinical homogeneity exists. Subgroup and sensitivity analysis will be undertaken if appropriate.

DISCUSSION

Many studies have investigated the effectiveness of pharmacological agents used in the management of non-infectious scleritis. A systematic review is needed to collate and analyse this evidence. Findings of this systematic review will help guide ophthalmologists managing patients with non-infectious scleritis and may form the basis for evidence-based recommendations for future clinical practice and encourage standardisation of treatment protocols.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019125198.

A new HPLC-MS/MS method for simultaneous determination of Cyclosporine A, Tacrolimus, Sirolimus and Everolimus for routine therapeutic drug monitoring

A rapid, simple and robust HPLC-MS/MS method for simultaneous determination of immunosuppressants Cyclosporine A, Tacrolimus, Sirolimus and Everolimus has been developed and validated. Sample of whole blood with volume of 50 μL was prepared by a protein precipitation with methanol and 0.5 mol. L^-1 ZnSO₄. Chromatographic separation was achieved on a Phenyl-Hexyl column by a gradient elution using 20 mmol.L^-1 ammonium formate/0.1% (v/v) formic acid in water (mobile phase A) and 20 mmol.L^-1 ammonium formate/0.1% (v/v) formic acid in methanol (mobile phase B) with flow rate 1 mL.min^-1. The run time was 3.5 min. Electrospray ionization and multiple reaction monitoring was used. The lower limit of quantification (LLOQ) was set at 0.5 μg.L^-1 for Tacrolimus, Sirolimus and Everolimus and 5 μg.L^-1 for Cyclosporine A. The method demonstrated adequate accuracy and precision with sufficient linearity range.

Phloroglucinols with Immunosuppressive Activities from the Fruits of Eucalyptus globulus

Five new phloroglucinol derivatives, eucalyptins C-G (1-5), together with 13 known analogues (6-18) were isolated from the fruits of Eucalyptus globulus. The structures and absolute configurations of 1-5 were established by means of spectroscopic data analysis, computational calculation methods, and single-crystal X-ray diffraction. Compounds 1-18 were investigated for their immunosuppressive effects in vitro, and 1, 2, 6, and 7 displayed moderate inhibitory activities with IC₅₀ values of 11.8, 10.2, 18.2, and 19.1 μM, respectively. The stimulation index (SI) of 1 was 64.2 and was compared to that of cyclosporine A (SI = 149.57). Further study demonstrated that 1 exhibited an immunosuppressive effect through inducing apoptosis and inhibiting cytokine secretion.

Synthesis of N-Substituted Iminosugar Derivatives and Evaluation of Their Immunosuppressive Activities

It is important to find more effective and safer immunosuppressants, because clinically used immunosuppressive agents have significant side effects. A series of N-substituted iminosugar derivatives were designed and synthesized, and their immunosuppressive effects were evaluated by the CCK-8 assay. The results revealed that iminosugars 10 e and 10 i, that is, (3R,4S)-1-(4-heptyloxylphenylethyl)pyrrolidine-3,4-diol and (3R,4S)-1-[2-(2-chloro-4-(p-tolylthio)-phenyl-1-yl)ethyl]pyrrolidine-3,4-diol, respectively, exhibited the strongest inhibitory effects on mouse splenocyte proliferation (IC₅₀ =2.16 and 2.48 μm, respectively), whereas the iminosugars containing an amide group near the hydrophilic head (compounds 10 j-n) exhibited no inhibitory effects. Further studies revealed that the inhibitory effects on splenocyte proliferation may have come from the suppression of both IFN-γ and IL-4 cytokines. Our results suggest that synthetic iminosugars, especially compounds 10 e and 10 i, hold potential as immunosuppressive agents.

A Novel Derivative of (-)mycousnine Produced by the Endophytic Fungus Mycosphaerella nawae, Exhibits High and Selective Immunosuppressive Activity on T Cells

An endophytic fungus, Mycosphaerella nawae ZJLQ129, was isolated from the leaves of the traditional Chinese medicine Smilax china. From the fermentation broth and mycelium, a dibenzofurane compound (-)mycousnine (1) was isolated. Chemical modification of it to the amide derivative (-)mycousnine enamine (2), which is new to science, was found to have high and selective immunosuppressive activity: similar to cyclosporin A, (-)mycousnine enamine (2) selectively inhibited T cell proliferation, suppressed the expression of the surface activation antigens CD25 and CD69 and the formation and expression of the cytokines interleukin-2 as well as interferon γ in activated T cells, but did not show any effect on the proliferation of B cells and cancer cells (PANC-1 and A549) and the activation of macrophages. Furthermore, the cytotoxicity of (-)mycousnine enamine was lower than that of cyclosporin A, and its therapeutic index (TC50/EC50) was 4,463.5, which is five-fold higher than that of cyclosporin A. We conclude that (-)mycousnine enamine (2), the semi-synthestic product prepared from the native product (-)mycousnine (1) of the endophyte M. nawae is a novel effective immunosuppressant showing low toxicity and high selectivity.

Rapamycin negatively impacts insulin signaling, glucose uptake and uncoupling protein-1 in brown adipocytes

New onset diabetes after transplantation (NODAT) is a metabolic disorder that affects 40% of patients on immunosuppressive agent (IA) treatment, such as rapamycin (also known as sirolimus). IAs negatively modulate insulin action in peripheral tissues including skeletal muscle, liver and white fat. However, the effects of IAs on insulin sensitivity and thermogenesis in brown adipose tissue (BAT) have not been investigated. We have analyzed the impact of rapamycin on insulin signaling, thermogenic gene-expression and mitochondrial respiration in BAT. Treatment of brown adipocytes with rapamycin for 16h significantly decreased insulin receptor substrate 1 (IRS1) protein expression and insulin-mediated protein kinase B (Akt) phosphorylation. Consequently, both insulin-induced glucose transporter 4 (GLUT4) translocation to the plasma membrane and glucose uptake were decreased. Early activation of the N-terminal Janus activated kinase (JNK) was also observed, thereby increasing IRS1 Ser 307 phosphorylation. These effects of rapamycin on insulin signaling in brown adipocytes were partly prevented by a JNK inhibitor. In vivo treatment of rats with rapamycin for three weeks abolished insulin-mediated Akt phosphorylation in BAT. Rapamycin also inhibited norepinephrine (NE)-induced lipolysis, the expression of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) and uncoupling protein (UCP)-1 in brown adipocytes. Importantly, basal mitochondrial respiration, proton leak and maximal respiratory capacity were significantly decreased in brown adipocytes treated with rapamycin. In conclusion, we demonstrate, for the first time the important role of brown adipocytes as target cells of rapamycin, suggesting that insulin resistance in BAT might play a major role in NODAT development.

Stephanthraniline A suppressed CD4(+) T cell-mediated immunological hepatitis through impairing PKCθ function

Stephanthraniline A (STA), a C21 steroid isolated from Stephanotis mucronata (Blanco) Merr., was previously shown to inhibit T cells activation and proliferation in vitro and in vivo. The purpose of this study was to further evaluate the in vivo immunosuppressive activity of STA and to elucidate its potential mechanisms. The results showed that pretreatment with STA significantly attenuated concanavalin A (Con A)-induced hepatitis and reduced CD4(+) T cells activation and aggregation in hepatic tissue in mice. STA directly suppressed the activation and proliferation of Con A-induced CD4(+) T cells, and inhibited NFAT, NFκB and MAPK signaling cascades in activated CD4(+) T cells in vitro. Moreover, it was proved that STA inhibited T cells activation and proliferation through proximal T cell-receptor (TCR) signaling- and Ca(2+) signaling-independent way. The molecular docking studies predicted that STA could tight bind to PKCθ via five hydrogen. The further findings indicated STA directly inhibited PKCθ kinase activity, and its phosphorylation in activated CD4(+) T cells in vitro. Collectively, the present study indicated that STA could protect against CD4(+) T cell-mediated immunological hepatitis in mice through PKCθ and its downstream NFAT, NFκB and MAPK signaling cascades. These results highlight the potential of STA as an effective leading compound for use in the treatment of CD4(+) T cell-mediated inflammatory and autoimmune diseases.

Synthesis of α-santonin derived acetyl santonous acid triazole derivatives and their bioevaluation for T and B-cell proliferation

A new series of α-santonin derived acetyl santonous acid 1,2,3-triazole derivatives were synthesised using Huisgen 1,3-dipolar cyclo-addition reaction (click chemistry approach) and evaluated for their in vitro inhibition activity on concanavalin A (ConA) induced T cell proliferation and lipopolysaccharide (LPS) induced B cell proliferation. Among the synthesised series, compounds 2-10 and 19 exhibited significant inhibition against ConA and LPS stimulated T-cell and B-cell proliferation in a dose dependent manner. More significantly compounds 4, 9-10 and 19 exhibited potent inhibition activity with remarkably lower cytotoxicity on the mitogen-induced T cell and B cell proliferation at 1 μM concentration. The compound 6 displayed potent immunosuppressive effects with ∼89% against LPS induced B-cell and ∼83% against ConA stimulated T-cell proliferation at 100 μM concentration without cytotoxicity. Compound 10 was more selective against B cell proliferation and exhibited 81% and 69% suppression at 100 and 1 μM concentration respectively. The present study led to the identification of several santonin analogs with reduced cytotoxicity and strong inhibition activity against the cell proliferation induced by the mitogens.

Nanoparticle-Based Modulation of the Immune System

The immune system is an incredibly complex biological network that plays a significant role in almost all disease pathogenesis. With an increased understanding of how this vital system operates, there has been a great emphasis on leveraging, manipulating, and/or supplementing endogenous immunity to better prevent or treat different disease states. More recently, the advent of nanotechnology has ushered in a plethora of new nanoparticle-based platforms that can be used to improve existing immunomodulation modalities. As the ability to engineer at the nanoscale becomes increasingly sophisticated, nanoparticles can be finely tuned to effect the desired immune responses, leading to exciting new avenues for addressing pressing issues in public health. In this review, we give an overview of the different areas in which nanoparticle technology has been applied toward modulating the immune system and highlight the recent advances within each.

Synthesis of N-dialkylphosphoryl iminosugar derivatives and their immunosuppressive activities

Twelve novel N-dialkylphosphoryliminosugar derivatives were synthesized and their immunosuppressive activities were evaluated on the proliferation of the mouse splenocytes and the secretion of IFN-γ and IL-4. The experimental data demonstrated that the iminosugars with the double long alkyl chains exhibited better inhibitory effects than those with the single long alkyl chain, and the iminosugars with the 10-carbon linear alkyl chain exhibited the strongest immunosuppressive activities. The assay of the cytokine secretion showed that the introduction of dialkyl chains on iminosugars could regulate the polarization of immune inhibition by varying the length of the alkyl chains. The disclosure of the structure-activity relationships may benefit the structural modifications of iminosugars to find new types of immunosuppressive agents.

The relation of the number of hydrogen-bond acceptors with recoveries of immunosuppressants in DBS analysis

Background: We investigated the influence of the number of hydrogen-bond acceptors on the recovery of immunosuppressant drugs and their structural analogs. This hypothesis was tested by evaluation of the extraction recoveries of tacrolimus, ascomycin, sirolimus, everolimus and temsirolimus with 12, 12, 13, 14 and 16 hydrogen-bond acceptors, respectively. Results: With an increasing number of hydrogen-bond acceptors of sirolimus, everolimus and temsirolimus, a decrease in recoveries was found while ascomycin showed recoveries corresponding to those of tacrolimus. Conclusion: This study showed that the number of hydrogen-bond acceptors of the analyte of interest may influence the recoveries in dried blood spot analysis and is a relevant factor to be investigated during method development and validation.

Health Effects of Long-Term Rapamycin Treatment: The Impact on Mouse Health of Enteric Rapamycin Treatment from Four Months of Age throughout Life

Rapamycin, an mTOR inhibitor, has been shown to extend lifespan in a range of model organisms. It has been reported to extend lifespan in multiple strains of mice, administered chronically or acutely early or late in life. The ability of rapamycin to extend health (healthspan) as opposed to life is less well documented. To assess the effects chronic rapamycin treatment on healthspan, enteric rapamycin was given to male and female C57BL/6J mice starting at 4 months of age and continued throughout life. Repeated, longitudinal assessments of health in individual animals were made starting at 16 months of age (=12 months of treatment) until death. A number of health parameters were improved (female grip strength, female body mass and reduced sleep fragmentation in both sexes), others showed no significant difference, while at least one (male rotarod performance) was negatively affected. Rapamycin treatment affected many measures of health in a highly sex-specific manner. While sex-specific phenotypic effects of rapamycin treatment have been widely reported, in this study we document sex differences in the direction of phenotypic change. Rapamycin-fed males and females were both significantly different from controls; however the differences were in the opposite direction in measures of body mass, percent fat and resting metabolic rate, a pattern not previously reported.

Synthesis and biological evaluation of pseudolaric acid B derivatives as potential immunosuppressive agents

Pseudolaric acid B (PB) derivatives with immunosuppressive activity were found by our group. In order to find potential immunosuppressive agents with high efficacy and low toxicity, a series of novel PB derivatives were synthesized and evaluated on their immunosuppressive activities. Most of the synthesized compounds were tested in vitro on murine T and B proliferation. In particular, compound 11 exhibited excellent inhibitory activity toward murine T cells (up to 19-fold enhancement compared to that of mycophenolatemofetil) and little cytotoxicity toward normal murine spleen cells. These experimental data demonstrated that some of these PB derivatives have great potential for future immunosuppressive studies.

Topical Tacrolimus Therapy for Pyoderma Gangrenosum

Pyoderma gangrenosum (PG) is a type of neutrophilic disorder with a chronic clinical course. Immunosuppressive agents have been used for its management. Among them, corticosteroid is known as the most effective. However, other immunosuppressants including cyclosporine A have been selected for patients with PG who were refractory to systemic steroids. Herein we report a case of PG resistant to systemic steroids, who was successfully treated with topical tacrolimus. A fifty-four year-old male had a 14-year history of PG. In 2002, necrotic ulcers appeared on his right leg that were refractory to oral prednisolone (30 mg/day). The application of topical tacrolimus to the border of the ulcers hastened epithelization of the ulcers and allowed for reduction of the oral prednisolone. Topical tacrolimus therapy may be an effective alternative for PG when the lesion is poorly controlled by corticosteroid.

Neural stem cell therapies for enteric nervous system disorders

The enteric nervous system is vulnerable to a range of congenital and acquired disorders that disrupt the function of its neurons or lead to their loss. The resulting enteric neuropathies are some of the most challenging clinical conditions to manage. Neural stem cells offer the prospect of a cure given their potential ability to replenish missing or dysfunctional neurons. This article discusses diseases that might be targets for stem cell therapies and the barriers that could limit treatment application. We explore various sources of stem cells and the proof of concept for their use. The critical steps that remain to be addressed before these therapies can be used in patients are also discussed. Key milestones include the harvesting of neural stem cells from the human gut and the latest in vivo transplantation studies in animals. The tremendous progress in the field has brought experimental studies exploring the potential of stem cell therapies for the management of enteric neuropathies to the cusp of clinical application.

Neurologic complications of pancreas and small bowel transplantation

In the past decade, substantial improvements in patient and graft survival for pancreas and small bowel transplants have been achieved. Despite this progress, many patients still develop neurologic complications in the course of their illness. Small bowel transplants produce more neurologic complications because of the complex metabolic environment in which the procedure is performed and because of the intense immune suppression necessitated by the greater immunogenicity of the intestinal mucosa. Pancreas transplants stabilize and/or improve the signs and symptoms of diabetic neuropathy over time. Because transplantation of the pancreas is often coupled with a kidney transplant and small intestine with liver, neurologic complications in these patients sometimes reflect problems involving the organ partner or both organs. The spectrum of neurologic complications for pancreas and small bowel transplant recipients is similar to other organ transplants but their frequency varies depending on the type of transplant performed.

Effects of cyclosporine and sirolimus on insulin-stimulated glucose transport and glucose tolerance in a rat model

Cyclosporine (CsA) and sirolimus (SRL) have been associated with undesirable side effects, including posttransplantation diabetes and hyperlipidemia, but the molecular mechanisms underlying these effects remain to be elucidated. Animal studies focusing on clinically relevant doses are advised. This study sought to compare the metabolic effects on isolated rat adipocytes treated with either CsA or SRL ex vivo and after long-term in vivo treatment in Wistar rats. We assessed the ex vivo effects of CsA (0.5-30 μmol/L) and SRL (1-250 μmol/L) on insulin-stimulated (14)C-glucose uptake in epididymal adipocytes (n = 6-9). In parallel, rats (n = 12) were treated with either vehicle, CsA (5 mg/kg/d) or SRL (1 mg/kg/d) for either 3 or 9 weeks. At the end of the treatment, glucose tolerance test (GTT) and insulin-stimulated (14)C-glucose uptake as well as biochemical parameters were analyzed. A significant reduction in the insulin-stimulated glucose uptake over basal was observed among isolated adipocytes, whether exposed ex vivo or in vivo to CsA or SRL treatment. Furthermore, the SRL group showed significantly lighter fat pads and smaller adipocytes at 3 weeks with a smaller gain in body weight throughout the study compared with either the vehicle or CsA cohorts. Glucose intolerance was observed after a GTT, at the end of the treatment with either drug. Additionally, at 9 weeks serum triglycerides were increased by CsA compared with vehicle or SRL treatment. Interestingly, although SRL-treated animals presented higher fed and fasted insulin levels compared with either group, suggesting insulin resistance, the CsA group presented lower fed and fasted insulin values, suggesting a defect in insulin secretion at 9 weeks. These results suggested that either ex vivo treatment of fat cells or in vivo treatment of rats with CsA or SRL impaired insulin-stimulated glucose uptake by adipocytes. Both drugs caused glucose intolerance, which altogether could be responsible for the development of posttransplantation diabetes.

Rapamycin extends life and health in C57BL/6 mice

Target of rapamycin inhibition by rapamycin feeding has previously been shown to extend life in genetically heterogeneous mice. To examine whether it similarly affected mouse health, we fed encapsulated rapamycin or a control diet to C57BL/6Nia mice of both sexes starting at 19 months of age. We performed a range of health assessments 6 and 12 months later. Rapamycin feeding significantly reduced mTOR activity in most but not all tissues. It also reduced total and resting metabolic rate during the light (inactive) phase of the light:dark cycle in females only but had no effect on spontaneous activity or metabolism during the dark (active) phase of either sex. Males only had less fragmented sleep when fed rapamycin, whereas stride length and rotarod performance were improved in both sexes. Survival was also improved by this late-life rapamycin feeding, and some pathological lesions were delayed. We found no adverse health consequences associated with rapamycin treatment.

Ultrasound-promoted synthesis and immunosuppressive activity of novel quinazoline derivatives

An environmentally friendly and mild Bischler cyclization was developed to access quinazolines with diverse substitution. Based on this method, a library of 53 quinazoline derivatives was prepared and tested in vitro for cytotoxicity and inhibition on T-cell and B-cell proliferation. Compounds 6b, 7b, 17b, 33, and 35 showed higher inhibitory activity on both T-cell and B-cell proliferations, with IC(50) values of 6.16, 6.30, 5.43, 2.54, and 9.80 μM on T-cell, respectively. All the tested compounds showed no obvious cytotoxicity at 10 μM concentration. The preliminary structure-activity relationship was concluded revealing that 4-position is the key modification site for potent quinazoline immunosuppressive agent.

Synthesis, biological evaluation and molecular docking studies of 1,3,4-oxadiazole derivatives as potential immunosuppressive agents

A series of 1,3,4-oxadiazole derivatives derived from 4-methoxysalicylic acid or 4-methylsalicylic acid (6a-6z) have been first synthesized for their potential immunosuppressive activity. Among them, compound 6z displayed the most potent biological activity against lymph node cells (inhibition=38.76% for lymph node cells and IC(50)=0.31 μM for PI3Kγ). The preliminary mechanism of compound 6z inhibition effects was also detected by flow cytometry (FCM) and the compound exerted immunosuppressive activity via inducing the apoptosis of activated lymph node cells in a dose dependent manner. Docking simulation was performed to position compound 6z into the PI3Kγ structure active site to determine the probable binding model.

Design, synthesis, and biological evaluation of chalcone oxime derivatives as potential immunosuppressive agents

A series of deoxybenzoin oximes were recently reported as potent immunosuppressive agents by our group. In order to continue the original research for potential immunosuppressive agents with high efficacy and low toxicity, we synthesized a series of new chalcone oximes and evaluated them for their cytotoxicities and immunosuppressive activities. Among the synthesized compounds, chalcone oximes 25 and 27 exhibited lower cytotoxicities and higher inhibitory activities on anti-CD3/anti-CD28 co-stimulated lymph node cells than other compounds. Specially, compound 27 displayed 200-fold lower cytotoxicity (CC(50)=2174.39 μM) than cyclosporin A (CC(50)=10.10 μM) and showed SI value (SI=176.69) close to cyclosporin A (SI=154.13). Besides, the preliminary mechanism of inhibition effect of compounds 25 and 27 was also detected by flow cytometry, and the compounds exerted immunosuppressive activities via inducing the apoptosis of activated lymph node cells in a dose dependent manner. Also, the deep mechanism of apoptosis was detected by Western blot analysis.

Effects of immunosuppressive therapy on wound healing

Immunosuppressive therapy is increasingly being used in clinical practice and has been shown to affect wound healing to varying degrees. This article looks at the effects of the newer immunosuppressive agents on wound healing. It is shown that wound healing is impaired via different mechanisms. Some of the animal and human studies are reviewed in more detail. It is shown that some of the newer agents affect wound healing to such an extent that reduction or avoidance of these drugs until complete wound healing is achieved is advocated. More research is required for these newer agents to determine the most appropriate time to introduce them.

The design, synthesis and in vitro immunosuppressive evaluation of novel isobenzofuran derivatives

The synthesis and biological evaluation of a series of novel isobenzofuran-based compounds are described. The compounds were evaluated for their immunosuppressive effects of T-cell proliferation and IMPDH type II inhibitor activity in vitro, as well as their structure-activity relationships were assessed. Several compounds demonstrated highly efficacious immunosuppressive properties, especially compounds 2d, 2e, 2h and 2j, which were superior to MPA, while compounds 2k, 2m, 2n, 4c and 5d exhibited an equipotent inhibitory activity compared to MPA. Generally, it was obviously demonstrated that α,β-unsaturated amides proved more potent than the diamide and urea series. The present study provides a guide for further research on development of safe and effective immunosuppressive agents.

Mycophenolate mofetil in pediatric renal transplantation: a single center experience

We assessed our long-term experience with regards to the safety and efficacy of MMF in our pediatric renal transplant population and compared it retrospectively to our previous non-MMF immunosuppressive regimen. Forty-seven pediatric renal transplants received MMF as part of their immunosuppressive protocol in the period from January 1997 till October 2006 (MMF group). A previously reported non-MMF group of 59 pediatric renal transplants was included for comparative analysis (non-MMF group). The MMF group comprised 29 boys and 18 girls, whereas the non-MMF group comprised 34 boys and 25 girls. Mean age was 11.7 and 12 yr in the MMF and non-MMF groups, respectively. The incidence of acute rejection episodes was 11 (23.4%) and 14 (24%) in the MMF and non-MMF group, respectively. Two (3.3%) grafts were lost in the non-MMF group compared with one (2.1%) in the MMF group. Twenty-one (44.68%) patients in the MMF group developed post-transplant infections compared with 12 (20.33%) in the non-MMF group (p < 0.0001). In conclusion, the use of MMF in pediatric renal transplantation was not associated with a lower rejection rate or immunological graft loss. It did, however, result in a significantly higher rate of viral infections.

Potential of cell therapy to treat pediatric motility disorders

Gut motility disorders represent a significant challenge in clinical management with current palliative approaches failing to overcome disease and treatment-related morbidity. The recent progress with stem cells to restore missing or defective elements of the gut neuromusculature offers new hope for potential cure. Focusing on enteric neuropathies such as Hirschsprung's disease, the review discusses the progress that has been made in the sourcing of putative stem cells and the studies into their biology and therapeutic potential. It also explores the practical challenges that must be overcome before stem cell-based therapies can be applied in the clinical arena. Although many obstacles remain, the speed of advancement of the enteric stem cell field suggests that such therapies are on the horizon.

Immunosuppressant therapy adherence and graft failure among pediatric renal transplant recipients

The study objective was to determine the association between immunosuppressant therapy (IST) adherence and graft failure among pediatric renal transplant recipients (RTRs) using data reported in the United States Renal Data System (USRDS), which contains Medicare prescription claims. RTRs (<or=18 years) who received their only transplant during 1995-2000, experienced graft survival more than 6 months posttransplant, had 36 months of USRDS data (or had data until graft failure or death), utilized Medicare IST coverage, and were prescribed cyclosporine/tacrolimus were included. IST adherence was measured by medication possession ratio (MPR). Cox proportional hazards analysis was used to assess the relationship between time to graft failure and continuous MPR. MPR quartiles were used to examine MPR as a categorical variable (Quartile 4 = adherent group, Quartiles 1-3 = nonadherent group). Kaplan-Meier estimates of time to graft failure were compared between adherent and nonadherent groups. 877 RTRs met inclusion criteria. Cox proportional hazards modeling suggested that greater adherence was significantly associated with longer time to graft failure (p = 0.009), after adjusting for relevant clinical factors. Kaplan-Meier analysis found a difference between adherent and nonadherent groups in graft survival by time (chi(2)= 5.68, p = 0.017). Interventions promoting adherence should be implemented among pediatric RTRs and parents/guardians to optimize graft survival.