Establishment of the culture technique of pulmonary vascular pericytes and its identification in rats

Intermedin: a skin peptide that is downregulated in atopic dermatitis

Intermedin (IMD), also called adrenomedullin-2, is a peptide that belongs to the calcitonin/calcitonin gene-related peptide/amylin peptide family. IMD exerts many effects on the cardiovascular system, gastrointestinal tract, and central nervous system. Here, we analyzed the expression of the IMD peptide in human skin of healthy controls, in biopsies from lesional and non-lesional areas of atopic dermatitis (AD) skin, in cultured human keratinocytes, and in the HaCaT keratinocyte cell line at the transcriptional (quantitative reverse transcription-PCR) and translational (immunohistochemistry) level. IMD messenger RNA (mRNA) and protein could be detected in keratinocytes and human skin. Keratinocytes, nerve fibers, periglandular cells, arterial/arteriolar smooth muscle cells, and pericytes of dermal microvessels were intensely IMD-immunoreactive. The IMD mRNA was, compared to healthy skin, significantly reduced in lesional and non-lesional areas of AD skin. This was accompanied by a reduction of IMD immunoreactivity in pericytes of the upper dermis indicating that skin from AD patients is generally affected, and downregulation of IMD in AD skin is not a secondary phenomenon caused by acute inflammation but is a general characteristic of AD skin. These data further point to a role of IMD expressed by pericytes in conferring higher susceptibility of the skin of AD patients to inflammatory stimuli.

Effects of DDPH on HECCM-induced proliferation and immunophenotypes of the pulmonary vascular pericytes

In order to study the effects of 1-(2, 6-dimethylphenoxy)-2-(3, 4-dimethoxyphenylethylamino) propane hydrochloride (DDPH) on proliferation and immunophenotypes of newborn rat pulmonary vascular pericytes induced by hypoxic endothelial cell conditioned medium (HECCM) from porcine pulmonary arteries, the cultured pericytes were divided into 4 groups according to the endothelial cell conditioned medium (ECCM) used: normoxic ECCM (NECCM) group, NECCM + DDPH group, HECCM group and HECCM + DDPH group. Cell culture, immunocytochemical staining, image analysis and flow cytometric method were used to investigate the effects of HECCM and DDPH on the expression of alpha-smooth muscle actin (alpha-SM-Actin) antigen, CD34 antigen, S-100 antigen and proliferating cell nuclear antigen (PCNA) and cell cycle in pericytes. The results showed that the alpha-SM-Actin antigen in the pericytes in HECCM group was stronger positively expressed than in the other three groups, but CD34 antigen and S-100 antigen were negatively expressed. The expression of alpha-SM-Actin antigen, CD34 antigen and S-100 antigen was positive in the groups of NECCM, NECCM + DDPH and HECCM + DDPH; The expression of alpha-SM-Actin and PCNA in HECCM group was 1.32 times (P < 0.01) and 1.24 times (P < 0.05) that in NECCM group, 1.30 times (P < 0.01) and 1.21 times (P < 0.05) that in HECCM + DDPH group, respectively. The percentage of the cells in the GO-G1 phase in the HECCM group was lower by 11.7% and 9.1%, in S phase higher by 5.6% and 4.2%, in G2-M phase higher by 6.1% and 4.9% than in the groups of NECCM, HECCM + DDPH, respectively. The inhibitory rate of DDPH on the increased alpha-SM-Actin and PCNA syntheses in pericytes induced by HECCM were 23.4% and 17.1% respectively. The inhibitory rate on the increased pericytes from GO-G1 phase to S phase was 8.3%. These results suggest that DDPH can directly inhibit pericytes from proliferation and immunophenotypical transformation of smooth muscle-like cells induced by HECCM.