Background: Corneal grafting is by far the most common form of transplantation. Many grafts suffer from immune rejection and current therapies are associated with many side effects, requiring more effective and safe therapies. alpha-Melanocyte stimulating hormone (alpha-MSH) is a neuropeptide that suppresses host inflammatory defense mechanisms. The purpose of this study was to determine the role of local therapy with alpha-MSH on corneal allograft survival, and the mechanisms by which it may influence graft outcome.
Methods: Orthotopic corneal transplantation was performed, with recipients receiving subconjunctival alpha-MSH or sham injections twice weekly. Grafts were followed up for 70 days, and graft inflammation/opacification was compared between the two groups in a masked fashion. Graft infiltration and ocular gene expression of select inflammatory cytokines was evaluated at different timepoints. Additionally, allospecific delayed-type hypersensitivity was compared among the groups 3 weeks posttransplantation.
Results: Results showed a significant increase in corneal graft survival in alpha-MSH-treated recipients compared with controls. Although 75% of allografts in alpha-MSH-treated hosts survived at 70 days, 43% survived in controls (P=0.04). Graft infiltration studies demonstrated a significant decrease in the number of mononuclear and polymorphonuclear cells in alpha-MSH-treated mice compared with controls at days 7 and 14 after transplantation. Furthermore, allospecific delayed-type hypersensitivity and gene expression of interferon-gamma and interleukin-2 showed a significantly reduced expression in alpha-MSH-treated mice compared with controls.
Conclusions: This study provides for the first time, in vivo evidence that treatment with local alpha-MSH may significantly reduce allorejection of orthotopic transplants.
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http://dx.doi.org/10.1097/TP.0b013e3181ac11ea | DOI Listing |
Front Physiol
January 2025
Regenerative Medicine Division, CHU de Quebec - Université Laval Research Centre, Quebec City, QC, Canada.
Introduction: Recent findings show that visible light, particularly blue light, stimulates melanogenesis in human skin, though the underlying mechanisms remain debated. This study aimed to determine the cell damage threshold of non-ionizing blue light on keratinocytes while preserving their ability to stimulate melanogenesis.
Methods: Human keratinocytes (N = 3) and melanocytes (N = 3) were isolated from skin samples of varying Fitzpatrick skin phototypes and irradiated with blue light (λpeak = 457 nm) and UVA light (λpeak = 385 nm).
Eur J Nucl Med Mol Imaging
January 2025
Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8675, Japan.
Purpose: Patients who develop metastatic melanoma have a very poor prognosis, and new treatments are needed to improve the response rates. Melanocortin-1 receptor (MC1R) is a promising target for radionuclide therapy of metastatic melanoma, and alpha-melanocyte stimulating hormone (α-MSH) peptide analogs show high affinities to MC1Rs. Because targeted alpha therapy (TAT) can be a desirable treatment for metastatic melanoma, this study aimed to develop an At-labeled α-MSH peptide analog for TAT of metastatic melanoma.
View Article and Find Full Text PDFBiosci Biotechnol Biochem
January 2025
Department of Genetics & Biotechnology, Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Youngin, Korea.
Eumelanin, a type of skin melanin pigment, possesses the ability to absorb a wide range of wavelengths, providing protection to the skin from ultraviolet radiation. However, excessive production of eumelanin may result in hyperpigmentation. Consequently, the development of skin-brightening products that suppress eumelanin synthesis to achieve a lighter and more even skin tone is necessary.
View Article and Find Full Text PDFJ Dermatol Sci
January 2025
Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan; Department of Frontier Science and Interdisciplinary Research, Faculty of Medicine, Kanazawa University, Ishikawa, Japan. Electronic address:
Background: Melanocytes protect the body from ultraviolet radiation by synthesizing melanin. Tyrosinase, a key enzyme in melanin production, accumulates in the endoplasmic reticulum (ER) during melanin synthesis, potentially causing ER stress. However, regulating ER function for melanin synthesis has been less studied than controlling Tyrosinase activity.
View Article and Find Full Text PDFSex Med
December 2024
Department of Biochemistry, Etlik City Hospital, Ankara, 06170, Turkey.
Background: Sexual dysfunction (SD) due to Selective Serotonin Reuptake Inhibitors (SSRI) use is a common condition encountered by psychiatrists and its etiology has not been fully elucidated.
Aim: To determine the relationship between alpha Melanocyte Stimulating Hormone (α-MSH) and Melanocortin-4 receptor (MCR4) levels and sexual function levels of patients with and without SSRI related SD and control group and to examine whether α-MSH and MCR4 play a role in the etiology of SSRI related SD.
Methods: A total of 92 patients and 49 healthy volunteers who applied to psychiatry outpatient clinic were included in the study.
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