Abstract

Human Skin Fibrosis: Up-regulation of Collagen type III gene transcription in the fibrotic skin nodules of lower limb lymphoedema

Arun Kumar Karayi1, Vijaya Basavaraj2, Saravu R Narahari3, Madhur Guruprasad Aggithaya3, Terence J Ryan4, and Rajendra Pilankatta1. Trop Med Int Health. 2019 Dec 9.

OBJECTIVES:

To investigate the cellular and molecular pathophysiology involved in the development of fibrotic skin of grade-3 lymphoedema patients with a focus on collagen types.

METHODS:

Fibrotic and normal skin biopsy samples obtained from grade-3 lymphoedema patients and normal individuals respectively were analysed by histopathology, quantitative Real-Time PCR and immunohistochemistry to examine collagen gene expression.

RESULTS:

Histopathologic analysis revealed epidermal changes such as orthokeratosis, hypergranulosis and irregular acanthosis in the skin biopsies. The thickened dermis contained nodules of haphazardly arranged thick collagen bundles. Real-Time PCR data showed significant (P-value 0.0003) up-regulation of Collagen type I and III gene transcripts in the fibrotic skin of patients resulting in 38.94-fold higher transcription of Collagen type III alpha-1 gene than of Collagen type I alpha-1 gene. Semi-quantification of the percent of hematoxylin-DAB-stained area of immunohistochemistry images also showed significant (P <0.0001) enhancement of both collagen proteins in the fibrotic skin of patients vs. normal human skin.

CONCLUSIONS:

Gene transcript analysis revealed significant up-regulation of Collagen type III vs. Collagen type I in fibrotic skin of limb nodules from patient biopsies. Histopathological and immunohistochemical analysis also revealed enhancement of Collagen types I and III in fibrotic vs. normal skin. The findings of this preliminary study indicate the potentially significant involvement of Collagen type III in the development of the fibrotic skin of grade-3 lymphoedema patients

Main findings

• Histopathological examinations revealed several epidermal and dermal alterations in the skin of grade-3 lymphoedema patients: orthokeratosis, hypergranulosis, and irregular acanthosis and a markedly thickened and oedematous dermis. The lymphatics were dilated and filled with eosinophilic proteinaceous material. There was also moderately dense perivascular infiltration by lymphocytes and plasma cells. MT staining highlighted haphazardly arranged thick collagen bundles showing nodular configuration in the thickened dermis.
• The histopathology slides of grade-3 lymphoedema patients’ skin showed thickened dermis with haphazardly arranged thick collagen bundles showing nodular configuration which might be similar to the micro-lobular architecture of thick tracts of fibrous tissue extending into the adipose layer of skin biopsies of nephrogenic fibrosing dermopathy (NFD) patients.
• Histopathology investigations of the fibrotic skin limb nodules of grade-3 lymphoedema patients show thickened dermis with nodules of haphazardly arranged thick collagen bundles. IHC data reveal enhanced and almost equal expression of both human skin collagens (COL-1 and COL-3) in the extracellular matrix of the fibrotic skin. In fibrotic skin tissue, COL-3-alpha-1 gene is increased 38.94-fold higher at gene transcription level than Col-1-alpha-1 gene. In comparison to normal skin, the fibrotic skin of grade-3 lymphoedema patients shows up-regulation of Col-3 gene transcription and its enhanced protein expression. Therefore our findings indicate the potentially significant involvement of Collagen type III in the development of the fibrotic skin of grade-3 lymphoedema patients by its synthesis at gene transcription level along with enhanced turnover at the protein level.