The anti-aging protein alpha-Klotho in systemic sclerosis patients: does a relationship to telangiectasia exist?

Iloprost infusion reduces serological cytokines and hormones of hypoxia and inflammation in systemic sclerosis patients

INTRODUCTION

Systemic sclerosis (SSc) is characterized by microvascular damage of skin and internal organs with chronic hypoxia and release of cytokines and hormones such as neutrophil gelatinase-associated lipocalin (NGAL), fibroblast growth factor-23 (FGF-23) and Klotho. Aim of the study was to evaluate FGF-23, Klotho and NGAL serum levels in SSc patients and healthy controls (HC) and to evaluate serum levels changes of FGF-23, Klotho and NGAL after Iloprost.

METHODS

Twenty-one SSc patients and 20 HC were enrolled. In SSc patients, peripheral venous blood samples were collected at the first day before the autumn Iloprost infusion (t0), 60 min (t1) and 14 days after Iloprost infusion (t2).

RESULTS

SSc patients had higher serum level of FGF-23 [18.7 ± 6.4 pg/ml versus 3.6 ± 2.2 pg/ml, p < 0.001], Klotho [5.1 ± 0.8 pg/ml versus 2.3 ± 0.6 pg/ml, p < 0.001] and NGAL [20.9 ± 2.6 pg/ml versus 14.5 ± 1.7 pg/ml, p < 0.001] than HC. Iloprost infusion reduces serum level of FGF-23 (18.7 ± 6.4 pg/ml versus 10.4 ± 5.5 pg/ml, p < 0.001), Klotho (5.1 ± 0.8 pg/ml versus 2.5 ± 0.6 pg/ml, p < 0.001) and NGAL (20.9 ± 2.6 pg/ml versus 15.1 ± 2.3 pg/ml, p < 0.001) between t0 and t1. The Iloprost infusion reduces serum level of FGF-23 (18.7 ± 6.4 pg/ml versus 6.6 ± 5.1 pg/ml), Klotho (5.1 ± 0.8 pg/ml versus 2.3 ± 0.4 pg/ml) and NGAL (20.9 ± 2.6 pg/ml versus 15.5 ± 1.9 pg/ml) between t0 and t2.

CONCLUSIONS

SSc patients had higher FGF-23, Klotho and NGAL than HC. Iloprost reduces serum levels of FGF-23, Klotho and NGAL.

Retinoic acid induces hyaluronic acid production through the klotho-mediated EGFR signaling pathway in human epidermal keratinocytes

All-trans retinoic acid (RA) is an effective anti-aging chemical substance widely used in skin-care products. RA compromises epidermal differentiation and induces keratinocyte proliferation, causing hyaluronic acid production through mechanisms that are not completely understood. Klotho protein causes the differentiation of human epidermal keratinocytes. Klotho gene expression is mediated by epidermal growth factor (EGF), which inhibits cell apoptosis in aging-related diseases. The klotho gene causes human aging syndrome, including short lifespan, skin atrophy, and osteoporosis. We investigated the relationship between RA and klotho in epidermal keratinocytes for the first time. In human epidermal keratinocytes, RA induced klotho gene expression. Treatment with both RA and recombinant klotho induced hyaluronic acid production in human epidermal keratinocytes. However, in klotho small interfering RNA (siRNA)-transfected keratinocytes, RA produced less hyaluronic acid than in the control group, indicating that RA may partially regulate hyaluronic acid production through a klotho-dependent pathway. Knockdown of klotho gene expression inactivated the EGFR-extracellular signal-regulated kinase (ERK) signaling pathway, which is involved in hyaluronic acid production. We concluded that the effect of RA on hyaluronic acid production is partly regulated through the klothomediated EGFR signaling pathway in human epidermal keratinocytes.