Low-intensity far-red light inhibits early lesions that contribute to diabetic retinopathy: in vivo and in vitro.

PURPOSE: Treatment with light in the far-red to near-infrared region of the spectrum (photobiomodulation [PBM]) has beneficial effects in tissue injury. We investigated the therapeutic efficacy of 670-nm PBM in rodent and cultured cell models of diabetic retinopathy. METHODS: Studies were conducted in streptozotocin-induced diabetic rats and in cultured retinal cells. Diabetes-induced retinal abnormalities were assessed functionally, biochemically, and histologically in vivo and in vitro. RESULTS: We observed beneficial effects of PBM on the neural and vascular elements of retina. Daily 670-nm PBM treatment (6 J/cm(2)) resulted in significant inhibition in the diabetes-induced death of retinal ganglion cells, as well as a 50% improvement of the ERG amplitude (photopic b wave responses) (both P < 0.01). To explore the mechanism for these beneficial effects, we examined physiologic and molecular changes related to cell survival, oxidative stress, and inflammation. PBM did not alter cytochrome oxidase activity in the retina or in cultured retinal cells. PBM inhibited diabetes-induced superoxide production and preserved MnSOD expression in vivo. Diabetes significantly increased both leukostasis and expression of ICAM-1, and PBM essentially prevented both of these abnormalities. In cultured retinal cells, 30-mM glucose exposure increased superoxide production, inflammatory biomarker expression, and cell death. PBM inhibited all of these abnormalities. CONCLUSIONS: PBM ameliorated lesions of diabetic retinopathy in vivo and reduced oxidative stress and cell death in vitro. PBM has been documented to have minimal risk. PBM is noninvasive, inexpensive, and easy to administer. We conclude that PBM is a simple adjunct therapy to attenuate the development of diabetic retinopathy.

Leukapheresis and cranial irradiation in patients with hyperleukocytic acute myeloid leukemia: no impact on early mortality and intracranial hemorrhage.

To assess the role of leukapheresis and cranial irradiation in reducing the incidence of intracranial hemorrhage (ICH) and early death in patients with hyperleukocytic acute myeloid leukemia (AML) and the impact of such treatment on survival. This study retrospectively analyzed the records of 75 patients with hyperleukocytic AML who had a white cell count over 100,000/microL. All patients had de novo AML except for two with therapy-related AML. Various factors were assessed for their impact on morbidity and mortality, particularly the role of pre-induction leukapharesis and cranial irradiation. The most significant risk factors for ICH were the presence of two or more symptoms of leukostasis (odds ratios [OR] 10.6, 95% CI: 2.67-42.02; P = 0.001) and respiratory distress (OR 5.41, 95% CI: 1.44-20.32, P = 0.012). The most significant risk factors for early death were age >or= 65 (OR 4.21, 95% CI: 1.45-12.21, P = 0.008), respiratory failure (OR 3.34, 95% CI: 1.24-9.50, P = 0.018), and two or more symptoms (OR 3.50 95% CI: 1.16-10.52, P = 0.026). Neither leukapheresis nor cranial irradiation were significantly associated with a decreased incidence of ICH (P = 0.349 and 0.378, respectively). Leukapheresis had no significant influence on early death (P = 0.367). The median survival patients receiving no pretreatment was 10.50 months (range 2.58-18.42) and for those receiving pretreatment 1.50 months (range 0.10-3.16; log-rank test, P = 0.062). Leukapheresis and cranial irradiation do not improve survival or decrease the incidence of ICH in adults with hyperleukocytic AML.