Neuroangiogenesis

Source: Wikipedia, the free encyclopedia.

Neuroangiogenesis is the coordinated growth of nerves and blood vessels.[1] The nervous and blood vessel systems share guidance cues and cell-surface receptors allowing for this synchronised growth. The term neuroangiogenesis only came into use in 2002[2] and the process was previously known as neurovascular patterning. The combination of neurogenesis and angiogenesis is an essential part of embryonic development and early life.[3] It is thought to have a role in pathologies such as endometriosis,[4] brain tumors,[5] and Alzheimer's disease.[6]

Physiology

Neurovascular patterning

Neurovascular development is the parallel emergence and patterning of the nervous system and the vascular system during embryogenesis and early life.

sema3A (semaphorin 3A) and (neuropilin).[7]

Mechanisms

Neuroangiogenic and axonal guidance molecules act on both

neuronal growth cones and endothelial tip cells in order to guide growth.[5]

Neuronal growth cones are situated on the tips of nerve cells and are responsive to different factors, both positive and negative. Growth of the neuron occurs by an extension of the actin (red in image) and microtubule (green in image) cytoskeleton.[8]

Neuronal growth cone

Tip cells found at the extremity of the developing blood vessel control adjacent endothelial cells to direct growth. Tip cells have receptors and ligands via which they respond to local neuroangiogenic factors.[8]

Neurogenic factors

There are many neuroangiogenic factors, some of which act to promote neuronal growth and vice versa.[5] The table shows examples

Neuroangiogenic factor Effect on neuron Effect on vascular endothelial cells Receptor/Ligand Origin
IGF-1 Promotion of neurogenesis and synaptogenesis EC proliferation, migration, and differentiation Ligand Liver cells
bFGF Proliferation of cortical progenitors and neurogenesis EC proliferation, migration, and differentiation Ligand
Adipocytes
NGF Neuron survival, differentiation Promotion of
ischemic
hindlimbs		 Ligand Multiple
Neuropilin Axon guidance
Synergistic
action of VEGF165 in EC migration and proliferation
Vascular development		 Receptor Target cell
VEGF Neuronal development and patterning, and has
neuroprotective
effects		 Induces angiogenesis, promotes
endothelial cell
survival, proliferation and migration		 Ligand Multiple

Pathology

Neuroangiogenesis is implicated in a number of pathologies, including endometriosis,

dementias, such as Alzheimer's disease.[6] Each of these incurs a significant cost for the healthcare industry, meaning that complete understanding of processes involved – including neuroangiogenesis – is necessary to enable development of functional treatments.[5][9]

Endometriosis

gynaecological disease caused by endometrial tissue implanting outside the uterus, a symptom of which is chronic pelvic pain. The formation, growth and persistence of these implants are dependent upon angiogenesis to increase the supply of blood vessels. The resulting increase in blood flow may correlate directly with pain symptoms.[citation needed] One possible explanation for this is the simultaneous growth of neurons into these areas alongside blood vessels through neuroangiogenesis.[4]

Brain tumors

Brain tumors, such as

glioblastoma multiforme, are characterized by dense vascularity associated with high expression of the proangiogenic factors, VEGF and interleukin 8.[5]

Brain injury

Following

angiopoietin-1.[5]

Alzheimer’s disease

A condition possibly resulting from a reduction in neuroangiogenic factors is Alzheimer’s disease. Without continued neuroangiogenesis during aging, areas of the brain may no longer have the full complement of functional

hypoxia, could be a vascular basis for Alzheimer's disease.[5][6][10]

See also

References

  1. PMID 25051436
    .
  2. ^ Park; et al. (2002). "Delayed Up-regulation of Vascular Endothelial Growth Factor and flk-1 after Global Cerebral Ischemia in Mongolian Gerbil -Possible roles in neuroangiogenesis?" (PDF). Korean Neurological Association. Retrieved 30 September 2015.
  3. ^
    PMID 19363295
    .
  4. ^
    PMID 21054165
    .
  5. ^
    PMID 24760128
    .
  6. ^
    PMID 22850316
    .
  7. PMID 12618135
    .
  8. ^
    PMID 14592405
    .
  9. PMID 24859987
    .
  10. PMID 27392865
    .
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