Applications of immunohistochemistry in the evaluation of immunosuppressive agents

Systemic Immunomodulatory Effects of Combinatorial Treatment of Thalidomide and Dexamethasone on T Cells and Other Immune Cells

PURPOSE

In organ transplantation, the need for immune modulation rather than immune suppression has been emphasized. In this study, we investigated whether combinatorial treatments of with thalidomide (TM) and dexamethasone (DX) might be new approaches to induce systemic immunomodulation on T cells and other immune cells that regulate the expression of co-inhibitory molecules.

MATERIALS AND METHODS

Naïve splenic T cells from C57BL/6 mice were sort-purified and cultured in vitro for CD4+ T cell proliferation and regulatory T cell (Treg) conversion in the presence of TM or/and DX. Expression of cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and programmed death-1 (PD-1) in proliferated and converted T cells was quantified by flow cytometry. We also quantified in vivo expression of CTLA-4 and PD-1 on splenic CD4+ T cells and other immune cells isolated from TM- or/and DX-treated mice. Mixed lymphocytes reactions (MLR) were performed to evaluate the capacity of immune cells in carrying out immune responses.

RESULTS

CTLA-4 expressions in effector T cells in vivo and in Tregs in vivo/vitro significantly increased upon TM/DX combinatorial treatment. Corresponding to increased CTLA-4 expression in T cells, the expression of ligand molecules for CTLA-4 significantly increased in splenic dendritic cells in TM/DX-treated groups. In addition, MLR results demonstrated that splenocytes isolated from TM/DX-treated mice significantly suppressed the proliferation of T cells isolated from other strains.

CONCLUSION

Based on these results, we suggest that TM/DX combinatorial treatments might be efficient immunomodulatory methods for regulating T cell immunity.

Enhanced immune-modulatory effects of thalidomide and dexamethasone co-treatment on T cell subsets

Thalidomide (TM) has been reported to have anti-cancer and anti-inflammatory properties, and dexamethasone (DX) is known to reduce inflammation and inhibit production of inflammatory cytokines. Many studies have reported that combinatorial therapy with TM and DX is clinically used to treat multiple myeloma and lupus nephritis, but the mechanism responsible for its effects has not been elucidated. In this study, we determined that TM and DX co-treatment had an enhanced immune-modulatory effect on T cells through regulating the expression of co-stimulatory molecules. Splenic naive T cells from C57BL/6 mice were sort-purified and cultured for CD4⁺ T cell proliferation and regulatory T (Treg) cell conversion in the presence of TM and/or DX. Following incubation with the drugs, cells were collected and OX40, 4-1BB, and glucocorticoid-induced tumour necrosis factor receptor-related protein (GITR) expression was quantified by flow cytometry. TM (1 or 10 μm) decreased CD4⁺ T cell proliferation in a dose-dependent manner, whereas TM/DX (0·1 or 1 nm) co-treatment further decreased proliferation. Treg cell populations were preserved following drug treatment. Furthermore, expression of co-stimulatory molecules decreased upon TM/DX co-treatment in effector T (Teff) cells and was preserved in Treg cells. Splenic CD4⁺ T cells isolated from TM- and DX-treated mice exhibited the same patterns of Teff and Treg cell populations as observed in vitro. Considering the selective effect of TM on different T cell subsets, we suggest that TM may play an immunomodulatory role and that TM/DX combinatorial treatment could further enhance these immunomodulatory effects by regulating GITR, OX40, and 4-1BB expression in CD4⁺ T cells.

Liposomal nano-drugs based on amphipathic weak acid steroid prodrugs for treatment of inflammatory diseases

BACKGROUND

Steroids are the most efficacious anti-inflammatory agents. However, their toxicities and side-effects compromise their clinical application. Various strategies and major efforts were dedicated for formulating viable liposomal glucocorticosteroids (GCs), so far none of these were approved.

OBJECTIVES

To evaluate these approaches for formulating GC-delivery systems, especially liposomes, and with focus on the Barenholz Lab experience.

METHODS

We developed PEGylated nano-liposomes (NSSL) remotely loaded with water-soluble amphipathic weak acid GC-prodrugs. Their remote loading results in high, efficient and stable loading to the level that enables human clinical use. We characterized them for their physical chemistry and stability. We demonstrated their therapeutic efficacy in relevant animal models and studied their pharmacokinetics (PK), biodistribution (BD) and pharmacodynamics advantages over the free pro-drugs.

RESULTS

Our steroidal nano-drugs demonstrate much superior PK, BD, tolerability and therapeutic efficacies compared to the free pro-drugs and to most drugs currently used to treat these diseases. These nano-drugs act as robust immune-suppressors, affecting cytokines secretion and diminishing hemorrhage and edema.

CONCLUSIONS

The combination of improved physical-chemistry, PK, BD, tolerability and therapeutic efficacy of these steroidal nano-drugs over the pro-drugs "as-is" support their further clinical development as potential therapeutic agents for treating inflammatory diseases.

The globalization of traditional medicine in northern peru: from shamanism to molecules

Northern Peru represents the center of the Andean "health axis," with roots going back to traditional practices of Cupisnique culture (1000 BC). For more than a decade of research, semistructured interviews were conducted with healers, collectors, and sellers of medicinal plants. In addition, bioassays were carried out to evaluate the efficacy and toxicity of plants found. Most of the 510 species encountered were native to Peru (83%). Fifty percent of the plants used in colonial times have disappeared from the pharmacopoeia. Market vendors specialized either on common and exotic plants, plants for common ailments, and plants only used by healers or on plants with magical purposes. Over 974 preparations with up to 29 different ingredients were used to treat 164 health conditions. Almost 65% of the medicinal plants were applied in these mixtures. Antibacterial activity was confirmed in most plants used for infections. Twenty-four percent of the aqueous extracts and 76% of the ethanolic extracts showed toxicity. Traditional preparation methods take this into account when choosing the appropriate solvent for the preparation of a remedy. The increasing demand for medicinal species did not increase the cultivation of medicinal plants. Most species are wild collected, causing doubts about the sustainability of trade.

Successful drug development despite adverse preclinical findings part 1: processes to address issues and most important findings

Unexpected adverse preclinical findings (APFs) are not infrequently encountered during drug development. Such APFs can be functional disturbances such as QT prolongation, morphological toxicity or carcinogenicity. The latter is of particular concern in conjunction with equivocal genotoxicity results. The toxicologic pathologist plays an important role in recognizing these effects, in helping to characterize them, to evaluate their risk for man, and in proposing measures to mitigate the risk particularly in early clinical trials. A careful scientific evaluation is crucial while termination of the development of a potentially useful drug must be avoided. This first part of the review discusses processes to address unexpected APFs and provides an overview over typical APFs in particular classes of drugs. If the mode of action (MoA) by which a drug candidate produces an APF is known, this supports evaluation of its relevance for humans. Tailor-made mechanistic studies, when needed, must be planned carefully to test one or several hypotheses regarding the potential MoA and to provide further data for risk evaluation. Safety considerations are based on exposure at no-observed-adverse-effect levels (NOAEL) of the most sensitive and relevant animal species and guide dose escalation in clinical trials. The availability of early markers of toxicity for monitoring of humans adds further safety to clinical studies. Risk evaluation is concluded by a weight of evidence analysis (WoE) with an array of parameters including drug use, medical need and alternatives on the market. In the second part of this review relevant examples of APFs will be discussed in more detail.

Pharmacological significance of triazole scaffold

The triazole nucleus is one of the most important and well known heterocycles which is a common and integral feature of a variety of natural products and medicinal agents. Triazole nucleus is present as a core structural component in an array of drug categories such as antimicrobial, anti-inflammatory, analgesic, antiepileptic, antiviral, antineoplastic, antihypertensive, antimalarial, local anaesthetic, antianxiety, antidepressant, antihistaminic, antioxidant, antitubercular, anti-Parkinson's, antidiabetic, antiobesity and immunomodulatory agents, etc. The broad and potent activity of triazole and their derivatives has established them as pharmacologically significant scaffolds. The basic heterocyclic rings present in the various medicinal agents are 1,2,3-triazole and 1,2,4-triazole. A large volume of research has been carried out on triazole and their derivatives, which has proved the pharmacological importance of this heterocyclic nucleus. The present paper is an attempt to review the pharmacological activities reported for triazole derivatives in the current literature with an update of recent research findings on this nuclei.