Long-term safety of tacrolimus ointment in atopic dermatitis

The impact of the use of immunosuppressive treatment after an embryo transfer in increasing the rate of live birth

The tolerance of the immune system for the semi-allogeneic embryo is promoted by several factors and the cells involved in the immune system and factors in the mother during pregnancy. The dysregulation of the immune responses between the mother and fetus is a risk factor that raises the likelihood of rejection of the embryo and reproductive failure. To safeguard embryos and prevent immunological attacks, it is critical to suppress immunological rejection and encourage immunological tolerance. Based on current medical literature, it seems that immune cell management through immunosuppressive therapies can address reproductive failures. Immunosuppressive treatment has demonstrated encouraging results in terms of enhancing outcomes related to pregnancy and rates of live birth by regulating the immune responses of mothers and positively impacting the reproductive processes of humans. Currently, there is scarcity of high-quality data regarding the safety and efficacy of immunosuppressive therapies for children and mothers. Therefore, it is important to exercise caution while selecting use of any immunosuppressive therapy in pregnancy. This mini review provides a comprehensive overview of the existing literature regarding the impact of Calcineurin Inhibitors and anti-TNF treatment on improving the live birth rate following embryo transfer.

Streptomyces tsukubensis VKM Aс-2618D-an Effective Producer of Tacrolimus

The Streptomyces sp. VKM Ac-2618D strain has been identified, and its morphological and physiological features have been studied in relation to the production of the immunosuppressant tacrolimus. The phenotypic variability of the strain was analyzed, and a dissociant with a high level of tacrolimus production was selected. Based on a comprehensive study of morphological, physiological, and chemotaxonomic properties and on phylogenetic analysis, the strain was named Streptomyces tsukubensis VKM Ac-2618D. The strain genome contains the full version of the tacrolimus biosynthetic gene cluster. The advantages of fed-batch cultivation mode for tacrolimus biosynthesis are shown. The results broaden the understanding of the characteristics of polyketide biosynthesis and can be used in the development of technology for tacrolimus production.

Anti-Inflammatory Activity of a Cyclic Tetrapeptide in Mouse and Human Experimental Models

A cyclic tetrapeptide Pro-Pro-Pheβ³ho-Phe (4B8M) was tested for immunosuppressive activity and potential therapeutic utility in several in vitro and in vivo mouse and human models. The tetrapeptide was less toxic for mouse splenocytes in comparison to cyclosporine A (CsA) and a parent cyclolinopeptide (CLA). The tetrapeptide demonstrated potent anti-inflammatory properties in antigen-specific skin inflammatory reactions to oxazolone and toluene diisocyanate as well to nonspecific irritants such as salicylic acid. It also inhibited inflammatory processes in an air pouch induced by carrageenan. In addition, 4B8M proved effective in amelioration of animal models corresponding to human diseases, such as nonspecific colon inflammation induced by dextran sulfate and allergic pleurisy induced by ovalbumin (OVA) in sensitized mice. The tetrapeptide lowered expression of EP1 and EP3 but not EP2 and EP4 prostaglandin E2 (PGE2) receptors on lipopolysaccharide-stimulated Jurkat T cells and ICAM-1 expression on human peripheral blood mononuclear cells (PBMC). Its anti-inflammatory property in the carrageenan reaction was blocked by EP3 and EP4 antagonists. In addition, 4B8M induced an intracellular level of PGE2 in a human KERTr keratinocyte cell line. In conclusion, 4B8M is a low toxic and effective inhibitor of inflammatory disorders with potential therapeutic use, affecting the metabolism of prostanoid family molecules.

Young children with moderate-to-severe atopic dermatitis can be treated safely and effectively with either topical tacrolimus or mild corticosteroids

AIM

We collected evidence and safety data for topical tacrolimus in small children with atopic dermatitis (AD) and compared the usage with topical corticosteroid.

METHODS

This was an interim analysis of 75 patients (55% female) at 1 year of an ongoing 3-year randomised open-label comparative follow-up study of topical tacrolimus vs corticosteroid treatment. One- to three-year-old children with moderate-to-severe eczema referred to the Skin and Allergy Hospital in Helsinki, Finland, were enrolled.

RESULTS

Efficacy parameters, the Eczema Area and Severity Index (EASI), Investigator's Global Assessment (IGA), transepidermal water loss (TEWL), eczema area, serum total immunoglobulin E (IgE) and the blood eosinophil count, showed improvement in both groups during the study. However, patients with signs of early sensitisation at baseline (elevated serum total IgE, elevated eosinophil count, positive prick tests or specific IgEs to aero or food allergens) had statistically significantly lower TEWL at the eczema site and a smaller eczema area at 12 months in the tacrolimus group. No severe adverse effects were seen during the treatment.

CONCLUSION

Children with AD and signs of early sensitisation appeared to benefit more from early tacrolimus than corticosteroid treatment. Small children may need stronger but nevertheless safe ointment options when treating moderate-to-severe AD.

Tacrolimus ointment for the treatment of adult and pediatric atopic dermatitis: Review on safety and benefits

Atopic dermatitis (AD) requires long-term management, mainly with topical anti-inflammatory agents. Topical corticosteroids (TCS) and tacrolimus ointment (TAC-O) are recommended as first-line treatments for AD. However, the long-term use of TCS is limited by cutaneous adverse events such as skin atrophy. For TAC-O, Japanese and US labelings were updated in 2003 and 2006, respectively, to include a boxed warning about a theoretical risk of skin cancer and lymphoma in patients treated with topical calcineurin inhibitors. However, TAC-O has been used worldwide for longer than 15 years to treat adult and pediatric patients with AD. Available data suggest that TAC-O is effective and well tolerated, and can improve quality of life. TAC-O has successfully been used in the proactive management of AD consisting of long-term intermittent use to prevent, delay or reduce the occurrence of AD flares. Systemic drug absorption after TAC-O application is negligible and unlikely to result in systemic immunosuppression. There is currently no strong evidence of an increased rate of malignancy in treated patients, and observational data from postmarketing surveillance studies have shown no safety concerns. In the absence of robust evidence, the warning about the carcinogenic potential in the Japanese labeling for TAC-O does not appear justified and should be reconsidered. This mitigation of description would allow adult and pediatric patients with AD to receive the effective treatment more appropriately.

Unraveling Nutritional Regulation of Tacrolimus Biosynthesis in Streptomyces tsukubaensis through omic Approaches

Streptomyces tsukubaensis stands out among actinomycetes by its ability to produce the immunosuppressant tacrolimus. Discovered about 30 years ago, this macrolide is widely used as immunosuppressant in current clinics. Other potential applications for the treatment of cancer and as neuroprotective agent have been proposed in the last years. In this review we introduce the discovery of S. tsukubaensis and tacrolimus, its biosynthetic pathway and gene cluster (fkb) regulation. We have focused this work on the omic studies performed in this species in order to understand tacrolimus production. Transcriptomics, proteomics and metabolomics have improved our knowledge about the fkb transcriptional regulation and have given important clues about nutritional regulation of tacrolimus production that can be applied to improve production yields. Finally, we address some points of S. tsukubaensis biology that deserve more attention.

[Ocular involvement in atopic dermatitis : Clinical aspects and therapy]

Patients with atopic dermatitis frequently complain of ocular symptoms. The general dermatitis can directly affect the periocular skin and patients often present with chronic atopic blepharokeratoconjunctivitis. Early diagnosis of the characteristic ophthalmological alterations, such as blepharitis, allergic conjunctivitis, keratoconjunctivitis sicca, conjunctival scarring with formation of symblepharon and lid malpositioning, filiform keratitis, corneal plaques, (persistent) epithelial defects, corneal ulcers and keratoconus as well as appropriate stage-adapted treatment, including lid hygiene with preservative-free lubricants, topical and sometimes systemic anti-inflammatory therapy and surgical treatment are important for patients to prevent long-term damage of the ocular surface leading to severe visual impairment.

dRNA-seq transcriptional profiling of the FK506 biosynthetic gene cluster in Streptomyces tsukubaensis NRRL18488 and general analysis of the transcriptome

FK506 (tacrolimus) is a valuable immunosuppressant produced by several Streptomyces strains. In the genome of the wild type producer Streptomyces tsukubaensis NRRL18488, FK506 biosynthesis is encoded by a gene cluster that spans 83.5 (kb). A whole transcriptome differential shotgun sequencing (dRNA-seq) of S. tsukubaensis was performed to analyze transcription at 2 different time points; before and during active FK506 production. In total, 8,914 transcription start sites were identified in either condition, which enabled precise determination of the 5'-UTR length of the corresponding transcripts as well as the identification of 2 consensus sequence motifs in the promoter regions. The transcription start sites of all gene operons within the FK506 cluster were identified, including 3 examples of leaderless RNA transcripts. These data provide detailed insight into the transcription of the FK506 biosynthetic gene cluster to support future regulatory studies, genetic manipulation, and industrial production.

15 year experience of tacrolimus application in medical practice

The review presents modern literature data on the use of tacrolimus in medical practice. The results of national and international research on the effectiveness and safety of the drug at various dermatoses are presented.

Target genes of the Streptomyces tsukubaensis FkbN regulator include most of the tacrolimus biosynthesis genes, a phosphopantetheinyl transferase and other PKS genes

Tacrolimus (FK506) is a 23-membered macrolide immunosuppressant used in current clinics. Understanding how the tacrolimus biosynthetic gene cluster is regulated is important to increase its industrial production. Here, we analysed the effect of the disruption of fkbN (encoding a LAL-type positive transcriptional regulator) on the whole transcriptome of the tacrolimus producer Streptomyces tsukubaensis using microarray technology. Transcription of fkbN in the wild type strain increases from 70 h of cultivation reaching a maximum at 89 h, prior to the onset of tacrolimus biosynthesis. Disruption of fkbN in S. tsukubaensis does not affect growth but prevents tacrolimus biosynthesis. Inactivation of fkbN reduces the transcription of most of the fkb cluster genes, including some all (for allylmalonyl-CoA biosynthesis) genes but does not affect expression of allMNPOS or fkbR (encoding a LysR-type regulator). Disruption of fkbN does not suppress transcription of the cistron tcs6-fkbQ-fkbN; thus, FkbN self-regulates only weakly its own expression. Interestingly, inactivation of FkbN downregulates the transcription of a 4'-phosphopantetheinyl transferase coding gene, which product is involved in tacrolimus biosynthesis, and upregulates the transcription of a gene cluster containing a cpkA orthologous gene, which encodes a PKS involved in coelimycin P1 biosynthesis in Streptomyces coelicolor. We propose an information theory-based model for FkbN binding sequences. The consensus FkbN binding sequence consists of 14 nucleotides with dyad symmetry containing two conserved inverted repeats of 7 nt each. This FkbN target sequence is present in the promoters of FkbN-regulated genes.

Phage p1-derived artificial chromosomes facilitate heterologous expression of the FK506 gene cluster

We describe a procedure for the conjugative transfer of phage P1-derived Artificial Chromosome (PAC) library clones containing large natural product gene clusters (≥70 kilobases) to Streptomyces coelicolor strains that have been engineered for improved heterologous production of natural products. This approach is demonstrated using the gene cluster for FK506 (tacrolimus), a clinically important immunosuppressant of high commercial value. The entire 83.5 kb FK506 gene cluster from Streptomyces tsukubaensis NRRL 18488 present in one 130 kb PAC clone was introduced into four different S. coelicolor derivatives and all produced FK506 and smaller amounts of the related compound FK520. FK506 yields were increased by approximately five-fold (from 1.2 mg L^-1 to 5.5 mg L^-1) in S. coelicolor M1146 containing the FK506 PAC upon over-expression of the FK506 LuxR regulatory gene fkbN. The PAC-based gene cluster conjugation methodology described here provides a tractable means to evaluate and manipulate FK506 biosynthesis and is readily applicable to other large gene clusters encoding natural products of interest to medicine, agriculture and biotechnology.

Topical tacrolimus with custom trays in the treatment of severe oral chronic graft-versus-host disease refractory to a potent topical steroid therapy: a case report

BACKGROUND

The authors present a case demonstrating the success of topical tacrolimus (TAC) therapy with custom trays in the treatment of oral chronic graft-versus-host disease (cGVHD). The 41-year-old male patient initially responded to topical steroid therapy (clobetasol propionate 0.05% ointment) applied both topically and with flexible carrier trays, but later became refractory to this potent topical agent. Topical TAC therapy with flexible carrier trays and systemic prednisone therapy was initiated.

RESULTS

The patient responded favorably with the change to topical TAC therapy with custom trays (and oral prednisone). His oral cGVHD lesions resolved within a period of 4 weeks. The improvement has remained stable at 14 months of follow-up.

CLINICAL IMPLICATIONS

This is the first case reported with regard to the successful resolution of steroid recalcitrant cGVHD successfully treated with topical TAC with custom trays.

Optimizing the treatment of atopic dermatitis in children: a review of the benefit/risk ratio of methylprednisolone aceponate

Atopic dermatitis (AD) is a chronic, recurring, pruritic, inflammatory skin condition which has its onset in early childhood in most cases. A stepped approach to therapy, starting with emollients and adding first mild and then more potent topical medications is recommended. For more than 50 years, topical corticosteroids (TCs) have been the gold standard in AD therapy. Increasingly potent TCs have tended to come with increasing risk of adverse events, however. Calculating the benefit/risk ratio [or therapeutic index (TIX)] for TCs when treating children and infants is more challenging in this population. Not only does their increased surface area to volume ratio as a result of their small size mean that they are likely to absorb a greater proportion of any active agent applied to their skin, but drug metabolism is slower than in adults and the systemic effects of corticosteroids are more pronounced (in particular reduction of serum cortisol levels through suppression of the hypothalamic-pituitary-adrenal axis). Unlike traditional TCs, topical calcineurin inhibitors are not associated with the systemic effects and have shown good efficacy in treating AD in children. Parental/Carer concerns about their long-term use can limit their acceptance for treatment in the paediatric population, however. Modifications to the structure of fourth generation corticosteroids mean that increased potency is not accompanied by increased risk of adverse events and hence they have an improved TIX. Methylprednisolone aceponate is a potent fourth generation corticosteroid which has demonstrated efficacy and safety in acute and maintenance programmes in infants and children. It is licenced for once-daily use, and is available in four formulations - ointment, fatty ointment, cream and milk, which combine with its improved TIX to meet the needs of young patients and their carers.

Alternative therapeutic advantages of catfish bile on atopic dermatitis: protection of T cell-mediated skin disease via antioxidant activities

Objectives

In the present study, we aimed to examine the anti-atopic properties of bile from the cat fish, Silurus asotus, to determine its possible use as a pharmaceutical product.

Methods

The anti-atopic activities of cat fish bile were examined in a non-cell antioxidant, in-vitro assay (splenocytes and mast cells) and a 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis-like mouse model.

Results

The results of these experiments revealed that Silurus asotus bile (SAB) scavenges radicals and protects proteins from superoxide attacks, suggesting that SAB suppresses the T helper (Th) type 2-skewed immune response. Th1/Th2 mRNA cytokines (interleukin (IL)-2, interferon (IFN)-γ and IL-4) from mouse splenocytes were effectively inhibited, and the release of β-hexosaminidase in RBL-2H3 mast cells was significantly suppressed by SAB. These results were supported by screening the Th1/Th2 cytokine mRNAs (IL-2, IFN-γ and IL-4) from lymph nodes in DNCB-treated mice. More dramatic results were observed in the histological changes at higher SAB concentrations (5%) compared to the therapeutic control, visualized using hematoxylin–eosin (H&E) staining.

Conclusions

The results presented in this study suggest that SAB may provide functional advantages with regard to treating atopic dermatitis because of its antioxidant and immune-suppressive effects.

A systematic review of tacrolimus ointment compared with corticosteroids in the treatment of atopic dermatitis

OBJECTIVE

A systematic review and meta-analysis was conducted to determine the efficacy and tolerability of tacrolimus ointment for the treatment of atopic dermatitis (AD) compared with topical corticosteroids.

METHODS

Electronic searches were performed in Medline, Embase and the Cochrane Library, as well as relevant conference proceedings. Two researchers independently selected trials investigating the efficacy and/or safety of tacrolimus ointment in the treatment of AD. No language restrictions were applied. Relevant outcome data from included trials were extracted by two independent reviewers. Direct meta-analysis to calculate relative risks (RR) (95% confidence intervals (CIs)) was conducted on dichotomous efficacy/safety outcomes of interest.

RESULTS

Seventeen trials comparing tacrolimus ointment with topical corticosteroids in both paediatric (n = 2328) and adult (n = 2849) patients were identified. No studies comparing tacrolimus ointment with class IV topical corticosteroids were identified. Tacrolimus 0.1% ointment was found to be of similar efficacy to class I/II and class III topical corticosteroids. In three individual trials (comparing tacrolimus 0.1% ointment to a topical corticosteroid), evaluation of the Physician's Global Evaluation of Clinical Response (PGECR) resulted in RRs of 0.95 (95% CI 0.78-1.16), 3.09 (95% CI 2.14-4.45) and 1.35 (95% CI 0.86-2.12), where values above one favour tacrolimus ointment. With the exception that tacrolimus ointment caused more skin burning than comparator treatments (tacrolimus 0.03% versus a class III topical corticosteroid, the RR was 3.00 (95% CI 1.21-7.43) in favour of the corticosteroid), no significant differences with regards to side-effects and withdrawals due to AEs were found. Quality of life data were reported in two studies. While one study reported greater improvements in tacrolimus-treated adult patients compared with topical steroids, the second reported greater improvements in paediatric patients treated with steroids compared with tacrolimus ointment.

CONCLUSIONS

The current review and meta-analysis showed tacrolimus ointment to be of similar efficacy to corticosteroids. The interpretation of available data is limited by heterogeneity in outcome measures between trials. Further trials are needed to assess the impact of treatments on patient reported outcomes.