In vitro genetically aberrant T-cell clones with continuous growth are associated with atopic dermatitis

Nanocrystals as an emerging nanocarrier for the management of dermatological diseases

Skin conditions are amongst the most prevalent health issues in the world and come with a heavy economic, social, and psychological burden. Incurable and chronic skin conditions like eczema, psoriasis, fungal infections are linked to major morbidity in the manner of physical pain and a reduction in quality life of patients. Several drugs have difficulties for penetrating the skin due to the barrier mechanism of the skin layers and the incompatible physicochemical characteristics of the drugs. This has led to the introduction of innovative drug delivery methods. Currently, formulations depend on nanocrystals have indeed been researched for topical administration of drugs and have resulted in enhanced skin penetration. This review focuses on skin penetration barriers, modern methods to enhance topical distribution, and the use of nanocrystals to overcome these barriers. By means of mechanisms such as adherence to skin, creation of diffusional corona, targeting of hair follicles, and the generation of a greater concentration gradient throughout the skin, nanocrystals could enhance transport across the skin. Scientists working on product formulations incorporating chemicals that are "challenging-to-deliver" topically may find the most current findings to be of relevance.

Emerging Nanomedicines for the Treatment of Atopic Dermatitis

Globally, the prevalence of Atopic dermatitis (AD) is significantly increasing and affecting around 20% of population including children. Complex interactions amongst abnormality in epidermal barrier function, environment, infectious agents and immunological defects are considered as key factors in the pathogenesis of AD. Although the role of oxidative stress has been studied in some skin diseases, investigation of the same in AD is intermittent. Calcineurin inhibitors and/or topical corticosteroids are currently available; however, it causes atrophy of the skin, burning sensation, and systemic side effects which leads to poor patient compliance. These limitations provoke the strong need to develop an innovative approach in managing AD. Nanomaterials for effective drug delivery to skin conditions such as AD have attracted a lot of attention owing to its ability to encapsulate, protect, and release the cargo at the diseased skin site. However, there are lots of unmet challenges especially in terms of development of non-toxic formulations and clinical translation of established nanomedicines in the form of accessible products. Numerous formulations have emerged as carrier for poorly soluble and permeable drugs, viz., lipidic, polymeric, metal, silica, liposomes, hydrocarbon gels and this field is evolving. This review is intended to provide an insight incidences associated with pathophysiology of AD and challenges with existing treatments of AD. Focus is kept on reviewing current development and emerging nanomedicines for effective treatment of AD. The review also inculcates merits of several nanomedicines in overcoming challenges of existing products and its future implications.

Targeting tacrolimus to deeper layers of skin with improved safety for treatment of atopic dermatitis-Part II: in vivo assessment of dermatopharmacokinetics, biodistribution and efficacy

The objective of present investigation was to study in vivo behavior of tacrolimus-loaded lipid-nanoparticles (T-LN) to understand its targeting potential for treatment of atopic-dermatitis-(AD). T-LN have shown significantly improved drug penetration to deeper epidermal and dermal skin-layers than commercial ointment-Protopic(®) and effectively reached target dendritic-immune-cells, responsible for immunopathogenesis of AD. Due to enhanced penetrability of T-LN, it became necessary to evaluate the toxicity of the nanocarrier and the drug at non-target tissues. This paper evaluates dermatopharmacokinetics (DPK), biodistribution, efficacy and safety of T-LN in comparison to Protopic(®) as reference. In vivo DPK in guinea pigs showed 3.02-fold higher bioavailability while γ-scintigraphy in albino-rats demonstrated 1.5-fold rapid penetration of radioactivity in skin for T-LN. Biodistribution in albino-rats revealed restricted localization at the target-skin-area with no general spreading to other body organs suggesting targeting potential of T-LN. In vivo efficacy studies in BALB/c mice showed highly efficient suppression of inflammatory AD-like skin-lesions with T-LN than reference and placebo. Dermal toxicity-studies revealed keratosis and collagenous mass-infiltration with repeated application of reference however interestingly, T-LN treated group showed no evident toxicity demonstrating significantly improved safety. Thus T-LN offered improved penetration to the target site without any toxic-effects and would represent an efficient and commercially viable alternative for AD treatment.

Cutaneous immunological activation elicited by a low-fluence pulsed dye laser

BACKGROUND

Three years ago, the nonablative wrinkle reduction laser (a 585-nm laser, Chromogenex V3; Chromogenex Light Technologies, Llanelli, U.K.) was developed, and there have already been several reports about its clinical effectiveness. The Chromogenex V3 laser has also been reported to be effective in treating acne and atopic dermatitis. These results suggest that the Chromogenex V3 laser has some immunological role. In this study, we investigated immunological changes elicited by laser irradiation at the ultrastructural level and by analysis of interleukin (IL)-2 and IL-4 mRNA in skin homing T lymphocytes.

MATERIALS AND METHODS

Eight healthy adult volunteers (mean age 56.3 years, range 25-66 years) were recruited for this study. Ultrastructural analysis was done 3 h after the laser irradiation, as well as 1 day, 3 days, 1 week, 2 weeks, 4 weeks and 5 weeks later. IL-2 and IL-4 mRNAs in skin homing T cells cultured for 6 weeks were semiquantitatively measured using reverse transcriptase-polymerase chain reaction.

RESULTS

Ultrastructural observations revealed that at 3 h after laser therapy, neutrophils, monocytes and mast cells could already be seen in the extravascular dermis. These dermal acute inflammatory changes were observed also at 1 week after laser treatment. Two weeks after laser treatment, the capillaries showed an almost normal structure. Four weeks after laser treatment, many lymphocytes and fibroblasts were observed. The numbers of these lymphocytes increased further at 5 weeks after the laser treatment. One week after the laser irradiation, all subjects were positive for IL-2 mRNA and for IL-4 mRNA. The level of IL-4 mRNA was larger compared with that of IL-2 mRNA in all subjects.

CONCLUSION

The Chromogenex V3 is a 585-nm visible light laser, and it may affect the skin not only by selective photothermolysis but also by direct cutaneous immunological activation.

Light-emitting Diode Phototherapy at 630.+-.3 nm Increases Local Levels of Skin-homing T-cells in Human Subjects

BACKGROUND AND AIMS

Red light phototherapy with laser sources has been used successfully for a number of indications. A new generation of quasimonochromatic 630 +/- 3 nm light-emitting diode (LED) systems has recently been yielding good results for the same indications, but no study has examined changes in visible red light irradiated skin at an immunological level. This study was thus designed to examine changes in skin-homing T-cell levels induced in normal human skin by visible red LED energy.

SUBJECTS AND METHODS

Six adult male volunteers (35 approximately 48 years old) who satisfied all study criteria had the skin over the lateral aspect of the leg irradiated once per week for 8 weeks with a visible red (630 +/- 3 nm) LED-based system, with irradiance of 105 m/cm2, 15 minutes/session, and a radiant flux of 94 J/cm2. Skin biopsies were performed after the eighth treatment session, and cultures were prepared to assay the type and quantity of skin-homing T-cells using qualitative and quantitative polymerase chain reaction (PCR) techniques. Ultrastructural changes were also assessed with transmission electron microscopy.

RESULTS

Transmission electron microscopy revealed mild fibroplastic changes in fibroblasts, with no acute inflammatory changes throughout the treatment session. Qualitative PCR showed the presence of both Th-1 and Th-2 T-cells, and quantitative PCR showed an increase in the numbers of both types of skin-homing T-cells, much more so for Th-2 than for Th-1.

CONCLUSIONS

Visible red LED irradiation appears to activate the skin-homing immune system.

Thymus is enlarged in children with current atopic dermatitis. A cross-sectional study

Atopic dermatitis is a common skin disorder of unknown aetiology with peak incidence in early childhood. The disease is associated with peripheral T-cell accumulation in the skin. The thymus is a key organ of the cellular immune response early in life. We hypothesized that atopic dermatitis is associated with an unbalanced establishment of the peripheral T-lymphocyte system. This cross-sectional study was performed to compare thymus sizes in patients with atopic dermatitis and healthy controls. Thirty-seven children with current atopic dermatitis were enrolled and compared with 29 healthy controls. An interview and medical examination were performed by one doctor, an ultrasound scan was performed within 3 days of the examination, and the thymus index, a marker of thymus size, was measured. The thymus index was on average 32% higher (95% CI 3%-67%) in children with active atopic dermatitis compared with healthy controls. It declined with age in both children with atopic dermatitis and healthy controls, but the reduction in size was only significant for healthy controls. We demonstrate increased size of thymus among children with active atopic dermatitis compared with healthy controls. The larger size of thymus is compatible with increased thymic activity and emission of T lymphocytes.

In vitro culture of skin-homing T lymphocytes from inflammatory skin diseases

We, in this study, describe how T lymphocytes in a skin biopsy can proliferate in vitro for up to 3 months by using T-cell growth factors - interleukin-2 (IL-2) and IL-4 yielding approximately 100-160 million T lymphocytes within 1 month. We established cell lines from three tuberculin skin tests, four positive patch tests, 15 of 16 biopsies from atopic dermatitis (AD), 15 of 19 biopsies from mycosis fungoides (MF), 12 of 24 biopsies from psoriasis vulgaris, which was significantly less than AD (P < 0.05), and with a reduced cumulative number of lymphocytes (P < 0.05). Omitting IL-2 and IL-4 led to immediate halt of proliferation. Blood mononuclear cells from patients and biopsies from healthy persons never gave cell lines. All cells were T lymphocytes expressing CD45RO+, HLA-DR+ and CD150. The CD7 expression was significantly increased in cell lines from AD (P < 0.05). T-cell receptor beta-chain studies by using reverse transcription-polymerase chain reaction showed that all T lymphocytes had access to the skin compartment. Single-stranded conformational analysis showed clonally expanded T cells numbering between 40 and 60 clones. After approximately 2 months of growth, the mean CD4+ : CD8+ ratio was for AD 1.20, MF 0.65 and psoriasis 0.85. Patients with AD treated with cyclosporin-A had almost no growth of CD8+ cells in vitro. Our findings indicate a changed homeostasis among skin-homing lymphocytes for in vitro culture. Our culture system of skin-homing T lymphocytes leads to a prominent cellular expansion allowing for a range of studies of in vivo activated skin T lymphocytes.

The effect of etanercept and infliximab on the production of tumour necrosis factor alpha, interferon-gamma and GM-CSF in in vivo activated intestinal T lymphocyte cultures

BACKGROUND/AIMS

Infliximab (Ifx) is effective in the treatment of Crohn's disease (CD) and rheumatoid arthritis (RA), etanercept (Eta) in RA but not in CD. The mechanisms underlying these clinical differences are not fully understood, but this knowledge could be valuable to identify responders and develop new treatments. This study compares Eta and Ifx in vitro regarding transmembrane tumour necrosis factor alpha (tmb-TNF-alpha) expression and interferon-gamma (IFN-gamma), TNF-alpha and granulocyte macrophage colony stimulating factor (GM-CSF) production in intestinal T lymphocytes.

METHODS

T lymphocyte cultures were established from biopsies from 10 CD patients and three healthy controls. The cytokine production and the expression of tmb-TNF-alpha were measured in the presence of Ifx/Eta.

RESULTS

Eta and Ifx downregulated the production of IFN-gamma and GM-CSF in colonic T lymphocytes from CD patients and healthy controls. Both drugs bound tmb-TNF-alpha on activated T lymphocytes besides neutralising TNF-alpha, Eta less efficiently than Ifx (406 pg/ml (337-475); 133 pg/ml (119-147); p=0.004). TNF-alpha was detectable with the present assay in cell lines cultured in the presence of excess Eta.

CONCLUSIONS

We have established that Eta is just as efficient as Ifx in downregulating IFN-gamma and GM-CSF production in vitro and Eta bound to tmb-TNF-alpha. However, Eta bound the TNF-alpha molecule, important in CD, less efficiently than Ifx.

Infliximab downregulates interferon-gamma production in activated gut T-lymphocytes from patients with Crohn's disease

The tumour necrosis factor-alpha (TNF-alpha) neutralizing antibody, Infliximab (Ifx), reduces disease activity in patients with active steroid-dependent or fistulizing Crohn's disease. The mechanisms underlying the effects of Ifx are not fully understood. This study aims to investigate if and how Ifx regulates the interferon-gamma (IFN-gamma) production in human intestinal T-cells. Colonic T cells were expanded from 25 patients with Crohn's disease and ten healthy controls in an in vitro system, using medium supplemented with interleukin-2 and interleukin-4 but without exogenous antigen. The effect of Ifx was investigated in these in situ activated T cell cultures regarding the IFN-gamma production, proliferation, transmembrane TNF-alpha expression, cytolysis and apoptosis. T cell cultures from patients with Crohn's disease produced significantly higher levels of IFN-gamma (<0.001) and TNF-alpha (P=0.04) than T cell cultures from healthy controls. The production of IFN-gamma was downregulated by Ifx in early T cell cultures (P=0.002). Ifx bound to transmembrane TNF-alpha of activated T cells without inducing complement-mediated cytolysis, apoptosis and without affecting proliferation. Besides its known TNF-alpha neutralizing property, Ifx downregulates INF-gamma production in colonic T cell cultures. Colonic T cells express transmembrane TNF-alpha that binds Ifx. The data suggest that Ifx reduces the level of at least two pro-inflammatory cytokines leading to lower disease activity.

CD4+ CD8+ (thymocyte-like) T lymphocytes present in blood and skin from patients with atopic dermatitis suggest immune dysregulation

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disease expressed early in life. Disease development is primarily determined by as yet unknown genetic factors, leading to the accumulation of activated T lymphocytes in the skin.

OBJECTIVES

To investigate the nature of these T cells.

METHODS

T-cell lines could be established from AD skin biopsies, but not from normal skin or AD peripheral blood, when placed in RPMI 1640 medium with 10% human AB serum, antibiotics, and the T-lymphocyte growth factors interleukins 2 and 4. The cell lines were subjected to phenotypic analysis using a fluorescence-activated cell sorter and compared with lymphocytes from AD and normal control peripheral blood.

RESULTS

T-cell lines from 22 of 24 consecutive skin biopsies taken from 24 adult patients with AD were established. All cells were T lymphocytes expressing several activation markers. A significant proportion of the lymphocytes had stable expression of a CD4+ CD8+ phenotype (26% +/- 6%; mean +/- SEM). Such double-positive T lymphocytes are normally only seen in the thymus and not in the peripheral immune system. CD4+ CD8+ cells in peripheral blood of the patients (12.5% +/- 3.3%) were also detected.

CONCLUSIONS

We suggest that a basic pathophysiological change in AD may be a faulty maturation of the T-lymphocyte system, leading to skin inflammation with CD4+ CD8+ T lymphocytes resembling immature T cells. This is likely to lead to skewing of many immune reactions in the patients.

Finite lifespans of T cell clones derived from CD34+ human haematopoietic stem cells in vitro

Several studies have documented finite lifespans of at least the vast majority of cultured human T cell lines and clones. However, there is a great deal of variation among the different preparations, ranging from < 25 PD up to > 100 PD. The cultured T cells in all these studies originated from mature T cells isolated from peripheral blood of adult donors. It was, therefore, impossible to assess the contribution of differences in in vivo age to the subsequent differences between clones in in vitro aging. In an attempt to circumvent this difficulty, we have developed a culture system that supports the differentiation of highly purified human CD34+ cells into CD3+ T cells in vitro. This features the use of a serum-free medium supplemented with the cytokines flt-3 ligand, IL 3, stem cell factor (c-kit ligand) and IL 2, together with IL 7 or oncostatin M (OM). In this way it is possible to perform "longitudinal" studies on T cells derived de novo in vitro. We show here that T cell clones derived under these circumstances also manifest variable finite life expectancies, for which the only uncontrolled (nonstochastic) effects of aging must already have occurred at the stem cell level.

Common clonal chromosome aberrations in cytokine-dependent continuous human T-lymphocyte cell lines

Antigen-mediated T-cell proliferation is a transient phenomenon. Like other somatic cells, T lymphocytes generally show replicative senescence in vitro. However, we here show that cytokine-dependent continuous (immortal) T-cell lines can be established from skin biopsy specimens of inflammatory skin diseases. Continuous growth can be obtained by culturing T cells in medium supplemented with interleukin-2 and interleukin-4, but without antigen or antigen-presenting cells added. Loss of the T-cell antigen receptor complex is observed in some of the continuous T-cell lines. Most T-cell lines develop clonal chromosome aberrations during continuous growth. Aberrations for chromosomes 1, 2, 8, 16, and 18 are most commonly observed.

No statistical association between fragile sites and constitutional chromosome breakpoints

Ten thousand four hundred ninety-two constitutional breakpoints available from the cytogenetic literature were analyzed for their coincidence with known fragile sites (FS) at 303-band resolution. In this analysis we have taken into account the stochastic connections of some features of chromosome bands with both the presence of FS and constitutional breakage. Our results suggest that there is no particular association between FS and constitutional chromosome rearrangements.

Appearance of isochromosome 18q can be associated with in vitro immortalization of human T lymphocytes

T lymphocytes cultured from a skin biopsy specimen of a patient with atopic dermatitis developed isochromosome 18q concomitant to escape from replicative senescence. Furthermore, two T-cell lines established from patients with cutaneous T-cell lymphoma also developed isochromosome 18q during continuous growth. The results indicate that a pathway leading to immortalization of human T lymphocytes could involve genes located at chromosome 18.