The Hypercalcemic Effect of Vitamin D3 in Sarcoidosis Could Be a Side Effect of an Endogenous Program Organizing Cancer Apoptosis

The cause of sarcoidosis is unknown, and vitamin D is contraindicated to treat the condition. We therefore ask what causes sarcoidosis and why vitamin D can be dangerous for those so afflicted. We propose a contrary hypothesis: sarcoidosis is a physiological process of defense against cancer that requires the substrate vitamin D. We tested this hypothesis, finding many case reports involving sarcoidosis and cancer—further cases of cancer mimicry by sarcoidosis. Several reports describe spontaneous healing of cancer in the presence of sarcoidosis. In the context of the granulomas of sarcoidosis, monocytes are the site of vitamin D release. Furthermore, active vitamin D can control cancer cells by using the vitamin D receptors of the nucleus. That granulomas consistently do not caseate is explained as a confrontation with human molecules and the cancer cells’ complete absorption. The striking fact that granulomas of sarcoidosis mostly lack cancerous cells is interpreted as a result of a well-functioning sarcoidosis process. We view the typical sarcoidosis monocytic synthesis of active vitamin D as a successful defense against cancer: a theory we call the “endogenous program organizing cancer apoptosis” (EPOCA).

Developmental regression of hyaloid vasculature is triggered by neurons

Vascular development involves not only vascular growth, but also regression of transient or unnecessary vessels. Hyaloid vasculature is the temporary circulatory system in fetal eyes, which spontaneously degenerates when the retinal blood vessels start to grow. Failure of the hyaloid vessels to regress leads to disease in humans, persistent hyperplastic primary vitreous, which causes severe intraocular hemorrhage and impairs visual function. However, the mechanism underlying the endogenous program that mediates spontaneous regression of the hyaloid vessels is not well understood. In this study, we identify a robust switch triggering this program directed by neurons in mice. Marked up-regulation of vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2) occurs in retinal neurons just after birth via distal-multipotent-mesodermal enhancer, a hemangioblast-specific enhancer of VEGFR2. Genetic deletion of neuronal VEGFR2 interrupts this program, resulting in massive hyaloid vessels that persist even during late postnatal days. This abnormality is caused by excessive VEGF proteins in the vitreous cavity as a result of impairment in the neuronal sequestration of VEGF. Collectively, our data indicate that neurons trigger transition from the fetal to the postnatal circulatory systems in the retina.