pericyteissä

Pericytes are contractile cells that wrap around the endothelial cells of capillaries and venules, forming a continuous perivascular layer that is essential for vascular integrity and function. Situated within the basement membrane, pericytes are linked to endothelial cells by peg‑wattle adhesions and gap junctions, allowing direct communication and exchange of signaling molecules. They regulate vascular tone, blood–brain barrier permeability, and capillary blood flow, and they play a crucial role in angiogenesis by releasing growth factors such as VEGF and PDGF.

During development, pericytes originate from mesenchymal progenitors and are recruited to nascent vessels via PDGF‑B/PDGFR‑β signaling. Once attached, they stabilize the blood vessels, promote maturation of the basement membrane, and influence surrounding tissues through extracellular matrix remodeling. In adulthood, pericytes remain dynamic, responding to injury by proliferating and differentiating into fibroblasts, myofibroblasts, or even neural progenitors in certain contexts.

Pericyte dysfunction is implicated in a range of diseases. Loss of pericytes contributes to the breakdown of the blood–brain barrier in Alzheimer’s disease, enhances tumor vascular permeability in cancers, and leads to retinal microvascular abnormalities in diabetic retinopathy. Genetic mutations affecting pericyte regulatory pathways, such as mutations in the ALDH1L1 gene, have also been linked to cerebral small vessel disease. Therapeutic strategies aimed at protecting or restoring pericyte function—through modulation of PDGF signaling, VEGF inhibition, or the use of stem cell-derived pericyte progenitors—are currently under investigation in preclinical models.

Research continues to uncover the complex interactions between pericytes and endothelial cells, as well as their contributions to tissue homeostasis, immune regulation, and organ regeneration. These insights are guiding the development of novel interventions for vascular disorders and highlighting the importance of pericytes in maintaining healthy microcirculation.