Photobiomodulation with near infrared light mitigates Alzheimer's disease-related pathology in cerebral cortex - evidence from two transgenic mouse models

A safety and feasibility study of the use of 670 nm red light in premature neonates

OBJECTIVE

Retinopathy of prematurity (ROP) is a vasoproliferative disorder of the retina affecting extremely preterm or low birth weight infants The aim of this study was to assess the feasibility and safety of 670 nm red light use in a neonatal intensive care unit.

STUDY DESIGN

Neonates <30 weeks gestation and <1150 g were enrolled within 48 h of birth. Data collected included cause of preterm delivery, Apgar scores and birthweight. 670 nm red light was administered for 15 min per day from a distance of 25 cm, delivering 9 J cm(-)(2), from the time of inclusion in the study until 34 weeks postmenstrual age. Infants were assessed daily for the presence of any skin burns or other adverse signs.

RESULT

Twenty-eight neonates were enrolled, seven 24 to 26 weeks and twenty-one 27 to 29 weeks gestation. The most common cause for preterm delivery was preterm labor (14/28) with five of these having evidence of chorioamnionitis. There were no skin burns or other documented adverse events. Entry into the study was readily achieved and treatment was well accepted by parents and nursing staff.

CONCLUSION

670 nm red light appears to be a safe and feasible treatment for further research in respect to ROP.

Near infrared (NIr) light increases expression of a marker of mitochondrial function in the mouse vestibular sensory epithelium

Strategies for attenuating decline in balance function with increasing age are predominantly focused on physical therapies including balance tasks and exercise. However, these approaches do not address the underlying causes of balance decline. Using mice, the impact of near infrared light (NIr) on the metabolism of cells in the vestibular sensory epithelium was assessed. Data collected shows that this simple and safe intervention may protect these vulnerable cells from the deleterious effects of natural aging. mRNA was extracted from the isolated peripheral vestibular sensory epithelium (crista ampullaris and utricular macula) and subsequently transcribed into a cDNA library. This library was then probed for the expression of ubiquitous antioxidant (SOD-1). Antioxidant gene expression was then used to quantify cellular metabolism. Using transcranial delivery of NIr in young (4 weeks) and older (8-9 months) mice, and a brief treatment regime (90 sec/day for 5 days), this work suggests NIr alone may be sufficient to improve mitochondrial function in the vestibular sensory epithelium. Since there are currently no available, affordable, non-invasive methods of therapy to improve vestibular hair cell function, the application of external NIr radiation provides a potential strategy to counteract the impact of aging on cellular metabolism inthe vestibular sensory epithelium.

Near infrared light mitigates cerebellar pathology in transgenic mouse models of dementia

We previously reported that Alzheimer-related pathology in cerebral cortex of APP/PS1 and K3 tau transgenic mouse strains is mitigated by near infrared light (NIr). Here, we extend these observations to the cerebellum. One month of NIr treatment mitigated the deposition of β-amyloid in cerebellar cortex of APP/PS1 mice, and the formation of neurofibrillary tangles, the hyperphosphorylation of tau, the damage caused by oxidative stress and the downregulation of cytochrome oxidase expression by Purkinje cells in the cerebellar cortex of K3 mice. These findings show the ability of NIr to mitigate degeneration in many - probably all - regions of the mouse brain.