KL and systemic sclerosis: As the expression levels of the anti-angiogenic VEGF165b isoform have been reported to be selectively increased in SSc-MVECs compared with H-MVECs [13], and considering that there are no anti-human α-Klotho antibodies suitable for a co-immunoprecipitation assay, we evaluated the expression of α-Klotho, VEGF165b, VEGFR-2 and TRPC-1 proteins in H-MVECs and SSc-MVECs (Fig. 6a–f).