Editing Capillary (section)

== Clinical significance ==
Disorders of capillary formation as a [[congenital|developmental defect]] or acquired disorder are a feature in many common and serious disorders. Within a wide range of cellular factors and cytokines, issues with normal genetic expression and bioactivity of the vascular growth and permeability factor [[vascular endothelial growth factor]] (VEGF) appear to play a major role in many of the disorders. Cellular factors include reduced number and function of bone-marrow derived [[endothelial progenitor cell]]s.<ref>{{cite journal |pages=1056–60 |doi=10.1111/j.1582-4934.2010.01077.x |title=Epicardium derived cells (EPDCs) in development, cardiac disease and repair of ischemia |year=2010 |last1=Gittenberger-De Groot |first1=Adriana C. |last2=Winter |first2=Elizabeth M. |last3=Poelmann |first3=Robert E. |journal=Journal of Cellular and Molecular Medicine |pmid=20646126 |pmc=3822740 |volume=14 |issue=5}}</ref> and reduced ability of those cells to form blood vessels.<ref name="circ.ahajournals.org">{{cite journal |pages=2986–92 |doi=10.1161/01.CIR.0000130639.97284.EC |title=Circulating Humoral Factors and Endothelial Progenitor Cells in Patients with Differing Coronary Collateral Support |year=2004 |last1=Lambiase |first1=P. D. |journal=Circulation |volume=109 |issue=24 |pmid=15184289 |last2=Edwards |first2=RJ |last3=Anthopoulos |first3=P |last4=Rahman |first4=S |last5=Meng |first5=YG |last6=Bucknall |first6=CA |last7=Redwood |first7=SR |last8=Pearson |first8=JD |last9=Marber |first9=MS|s2cid=12041051 |url=http://discovery.ucl.ac.uk/7831/1/7831.pdf |doi-access=free }}</ref>
* Formation of additional capillaries and larger blood vessels (angiogenesis) is a major mechanism by which a cancer may help to enhance its own growth. Disorders of retinal capillaries contribute to the pathogenesis of age-related [[macular degeneration]].
* Reduced capillary density (capillary rarefaction) occurs in association with cardiovascular [[Risk factor (epidemiology)|risk factor]]s<ref>{{cite journal |pages=1873–9 |doi=10.1172/JCI119354 |pmc=508011 |title=Impaired microvascular dilatation and capillary rarefaction in young adults with a predisposition to high blood pressure |year=1997 |last1=Noon |first1=J P |last2=Walker |first2=B R |last3=Webb |first3=D J |last4=Shore |first4=A C |last5=Holton |first5=D W |last6= Edwards |first6=H V |last7=Watt |first7=G C |journal=Journal of Clinical Investigation |volume=99 |issue=8 |pmid=9109431}}</ref> and in patients with [[coronary heart disease]].<ref name="circ.ahajournals.org"/>

=== Therapeutics ===
Major diseases where altering capillary formation could be helpful include conditions where there is excessive or abnormal capillary formation such as cancer and disorders harming eyesight; and medical conditions in which there is reduced capillary formation either for familial or genetic reasons, or as an acquired problem.
* In patients with the retinal disorder, neovascular age-related [[macular degeneration]], local [[anti-VEGF therapy]] to limit the bio-activity of [[vascular endothelial growth factor]] has been shown to protect vision by limiting progression.<ref>{{cite journal |pages=3033–41 |doi=10.1172/JCI42437 |title=Therapeutic targets in age-related macular disease |year=2010 |last1=Bird |first1=Alan C. |journal=Journal of Clinical Investigation |volume=120 |issue=9 |pmid=20811159 |pmc=2929720}}</ref> In a wide range of cancers, treatment approaches have been studied, or are in development, aimed at decreasing tumour growth by reducing angiogenesis.<ref>{{cite journal |pages=3962–73 |doi=10.2741/3504 |title=Tumor angiogenesis and molecular targets for therapy |year=2009 |last1=Cao |first1=Yihai |journal=Frontiers in Bioscience |issue=14 |pmid=19273326 |volume=14|doi-access=free }}</ref>

=== Blood sampling ===
Capillary blood sampling can be used to test for [[blood glucose]] (such as in [[blood glucose monitoring]]), [[hemoglobin]], [[pH]] and [[lactic acid|lactate]].<ref>{{Cite journal|last1=Krleza|first1=Jasna Lenicek|last2=Dorotic|first2=Adrijana|last3=Grzunov|first3=Ana|last4=Maradin|first4=Miljenka|date=15 October 2015|title=Capillary blood sampling: national recommendations on behalf of the Croatian Society of Medical Biochemistry and Laboratory Medicine|pmc=4622200|journal=Biochemia Medica|volume=25|issue=3|pages=335–358|doi=10.11613/BM.2015.034|issn=1330-0962|pmid=26524965}}</ref><ref>{{Cite journal|last1=Moro|first1=Christian|last2=Bass|first2=Jessica|last3=Scott|first3=Anna Mae|last4=Canetti|first4=Elisa F.D.|date=19 January 2017|title=Enhancing capillary blood collection: The influence of nicotinic acid and nonivamide|journal=Journal of Clinical Laboratory Analysis|language=en|volume=31|issue=6|pages=e22142|doi=10.1002/jcla.22142|pmid=28102549|pmc=6817299|issn=0887-8013|doi-access=free}}</ref> It is generally performed by creating a small cut using a [[blood lancet]], followed by [[sampling (medicine)|sampling]] by [[capillary action]] on the cut with a [[Glucose meter|test strip]] or small [[pipette]].<ref name="niddk">{{cite web |title=Managing diabetes:Check your blood glucose levels |url=https://www.niddk.nih.gov/health-information/diabetes/overview/managing-diabetes#bloodGlucose |publisher=National Institute of Diabetes and Digestive and Kidney Diseases,US National Institutes of Health |access-date=9 September 2021 |date=2021}}</ref> It is also used to test for [[sexually transmitted infections]] that are present in the blood stream, such as [[HIV]], [[syphilis]], and [[Hepatitis|hepatitis B and C]], where a finger is lanced and a small amount of blood is sampled into a [[test tube]].<ref>{{Cite web|url=https://fettle.health/help-centre/how-to-take-a-blood-sample|title=Fettle - How to take a blood sample|access-date=16 March 2023|url-status=live|archive-url=https://web.archive.org/web/20230316221208/https://fettle.health/help-centre/how-to-take-a-blood-sample|archive-date=16 March 2023}}</ref>