Apoptosis

Refers to the process of endogenously facilitated cell-death. It co-occurs with signs of cellular stress and is a way for the body to minimise the negative consequence of cellular injury and death, like DNA-damage and leakage of harmful intracellular enzymes onto healthy cells and tissues, and also to promote efficient recycling of resources. It is also a way for the body to eliminate intracellular parasites that is trying to hijack cellular energetic and anabolic systems. However, parasites might also exploit the apoptotic mechanism, both by inhibiting it, which allows for their growth and replication, and by stimulating it, which promotes dissemination once they have consumed enough intracellular resources. Apoptosis is usually associated with hyperplasia, as a natural response to replace lost cells but in chronic disease this cycle may become persistent if the underlying stressor is unrelenting. The degree of apoptosis can simultaneously be up- and down-regulated in the same tissue but in different cell-types.

Supporting Evidence

• Apoptosis is used and modulated by both host and pathogens for their respective benefit in infection.¹⁾https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3241725/²⁾https://www.nature.com/articles/cdd201617
• Apoptosis, autophagy and ROS are closely related in pathology.³⁾https://www.ncbi.nlm.nih.gov/pubmed/32197645

Association with Disease

• Increased apoptotic tendencies in fibroblast cultured from patients with MPS.⁴⁾https://www.sciencedirect.com/science/article/pii/S0925443915000691
• Increased apoptosis of parenchymal cells in TP (including tears), OA, DDD and AS.⁵⁾https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2505234/⁶⁾https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2843163/⁷⁾https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5264298/⁸⁾https://academic.oup.com/bmb/article/122/1/123/3084414⁹⁾https://www.ncbi.nlm.nih.gov/pubmed/18851798¹⁰⁾https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4661802/¹¹⁾https://ard.bmj.com/content/59/12/959¹²⁾https://www.ncbi.nlm.nih.gov/pubmed/17051327¹³⁾https://www.ncbi.nlm.nih.gov/pubmed/23512131¹⁴⁾https://www.ncbi.nlm.nih.gov/pubmed/10728396¹⁵⁾https://www.ncbi.nlm.nih.gov/pubmed/14501585
• Apoptotic pathways are suppressed in cells from synovial tissue in RA, but are increased in cartilage.¹⁶⁾https://www.longdom.org/open-access/apoptosis-resistance-in-rheumatoid-arthritis-synovial-tissue-2155-9899.S3-006.pdf¹⁷⁾https://academic.oup.com/rheumatology/article/49/5/862/1786468¹⁸⁾https://www.ncbi.nlm.nih.gov/pubmed/12707581¹⁹⁾https://www.sciencedirect.com/science/article/pii/S1471489203000377²⁰⁾https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4751576/
• Apoptosis of mainly macrophages and smooth-muscle cells in AS.²¹⁾https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4762053/