Potentials of Noninvasive Low-Level Laser Therapy for Neonatal Thrombocytopenia

More than 20% of all newborns admitted to the neonatal intensive care unit experience abnormally low platelet counts, called neonatal thrombocytopenia. Neonatal thrombocytopenia could increase a risk of hemorrhage, especially within the brain and adversely affect its development. No drugs or therapies are currently available for these sick newborns besides platelet transfusions. However, too many platelet transfusions could induce anti-platelet autoantibodies and other complications in some cases. One innovative idea for an alternative and non-invasive therapy for thrombocytopenia is low-level laser treatment (LLLT). LLLT is very safe, like blue-light-mediated treatment of newborn jaundice that has been used in clinics for decades with a long record of safety. LLLT stimulates the expression of a group of genes involved in mitochondrial generation in megakaryocytes (MKs) that are the precursor of platelets. This stimulation increases mitochondrial mass in MKs and enlarges the cells, which in turn elevates the rate of platelet production per MK. Our early investigation demonstrated that LLLT could quickly increase the number of circulating platelets and greatly reduce the risk of bleeding in thrombocytopenic adult animals. To explore a potential of this novel modality in management of neonatal thrombocytopenia, we investigated whether LLL could increase the platelet biogenesis in fetal liver and bone marrow MKs that intended to have low polyploidy compared to those MKs in adults. We found that LLL enhanced platelet production in MKs differentiated from fetal bone marrow and livers albeit at a slightly less efficiency. In addition to increased production of platelets from MKs, LLL appeared to increase the number of MKs differentiated from MK precursors in both bone marrow and liver of newborn mice in vivo as well, in contrast to little megakaryocytopoiesis induced by LLLT in adult mice. The ability of LLLT to increase not only platelet generation from MKs but also megakaryocytopoiesis in both livers and bone marrows in newborns suggests a potential for LLLT to manage neonatal thrombocytopenia and reduce the number of transfusions for thrombocytopenia-afflicted newborns.