title: Angiogenesis in gastric mucosa: an important component of gastric erosion and ulcer healing and its impairment in aging.
abstract: Angiogenesis (also referred to as neovascularization-formation of new blood vessels from existing vessels) is a fundamental process essential for healing of tissue injury and ulcers because regeneration of blood microvessels is a critical requirement for oxygen and nutrient delivery to the healing site. This review article updates the current views on angiogenesis in gastric mucosa following injury and during ulcer healing, its sequential events, the underlying mechanisms, and the impairment of angiogenesis in aging gastric mucosa. We focus on the time sequence and ultrastructural features of angiogenesis, hypoxia as a trigger, role of vascular endothelial growth factor signaling (VEGF), serum response factor, Cox2 and prostaglandins, nitric oxide, and importin. Recent reports indicate that gastric mucosa of aging humans and experimental animals exhibits increased susceptibility to injury and delayed healing. Gastric mucosa of aging rats has increased susceptibility to injury by a variety of damaging agents such as ethanol, aspirin, and other non-steroidal anti-inflammatory drugs because of structural and functional abnormalities including: reduced gastric mucosal blood flow, hypoxia, reduced expression of vascular endothelial growth factor and survivin, and increased expression of early growth response protein 1 (egr-1) and phosphatase and tensin homolog (PTEN). Until recently, postnatal neovascularization was assumed to occur solely through angiogenesis sprouting of endothelial cells and formation of new blood vessels from pre-existing blood vessels. New studies in the last decade have challenged this paradigm and indicate that in some tissues, including gastric mucosa, the homing of bone marrow-derived endothelial progenitor cells to the site of injury can also contribute to neovascularization by a process termed vasculogenesis.
authors.affiliation: Veterans Administration Long Beach Healthcare System, 5901 E. Seventh Street, Long Beach, CA, 90822, USA; The University of California, Irvine, CA, USA.
authors.forename: Andrzej S
authors.initials: AS
authors.lastname: Tarnawski
authors.forename: Amrita
authors.initials: A
authors.lastname: Ahluwalia
authors.forename: Michael K
authors.initials: MK
authors.lastname: Jones
mesh_terms: D000375:Aging / Q000473:pathology* / Q000502:physiology*; D001854:Bone Marrow Cells; D051546:Cyclooxygenase 2 / Q000502:physiology; D051766:Early Growth Response Protein 1 / Q000378:metabolism; D066026:Endothelial Progenitor Cells / Q000502:physiology; D005753:Gastric Mucosa / Q000098:blood supply* / Q000473:pathology* / Q000502:physiology*; D006801:Humans; D028884:Karyopherins / Q000502:physiology; D009389:Neovascularization, Pathologic / Q000235:genetics; D009569:Nitric Oxide / Q000502:physiology; D051059:PTEN Phosphohydrolase / Q000378:metabolism; D011453:Prostaglandins / Q000502:physiology; D012038:Regeneration / Q000235:genetics / Q000502:physiology*; D026362:Serum Response Factor / Q000502:physiology; D013276:Stomach Ulcer / Q000473:pathology* / Q000503:physiopathology*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism / Q000502:physiology
chemical_list: C497325:EGR1 protein, human; D051766:Early Growth Response Protein 1; D028884:Karyopherins; D011453:Prostaglandins; D026362:Serum Response Factor; D042461:Vascular Endothelial Growth Factor A; D009569:Nitric Oxide; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human
keywords: aging gastric mucosa; angiogenesis; growth factors; healing; injury; serum response factor