Effects of Indocyanine green on cultured retinal ganglion cells in-vitro

Lasing in blood

Indocyanine green (ICG) is the only near-infrared dye approved by the U.S. Food and Drug Administration for clinical use. When injected in blood, ICG binds primarily to plasma proteins and lipoproteins, resulting in enhanced fluorescence. Recently, the optofluidic laser has emerged as a novel tool in bio-analysis. Laser emission has advantages over fluorescence in signal amplification, narrow linewidth, and strong intensity, leading to orders of magnitude increase in detection sensitivity and imaging contrast. Here we successfully demonstrate, to the best of our knowledge, the first ICG lasing in human serum and whole blood with the clinical ICG concentrations and the pump intensity far below the clinically permissible level. Furthermore, we systematically study ICG laser emission within each major serological component (albumins, globulins, and lipoproteins) and reveal the critical elements and conditions responsible for lasing. Our work marks a critical step toward eventual clinical and biomedical applications of optofluidic lasers using FDA approved fluorophores, which may complement or even supersede conventional fluorescence-based sensing and imaging.

Neurotoxic effects of indocyanine green -cerebellar granule cell culture viability study

The aim of this study was to examine neurotoxicity indocyanine green (ICG). We assessed viability of primary cerebellar granule cell culture (CGC) exposed to ICG to test two mechanisms that could be the first triggers causing neuronal toxicity: imbalance in calcium homeostasis and the degree of oligomerization of ICG molecules. We have observed this imbalance in CGC after exposure to 75-125μΜ ICG and dose and application sequence dependent protective effect of Gadovist on surviving neurons in vitro when used with ICG. Spectroscopic studies suggest the major cause of toxicity of the ICG is connected with oligomers formation. ICG at concentration of 25 μM (which is about 4 times higher than the highest concentration of ICG in the brain applied in in-vivo human studies) is not neurotoxic in the cell culture.

Reduction of thickness of ganglion cell complex after internal limiting membrane peeling during vitrectomy for idiopathic macular hole

BACKGROUND/AIM

The aim of this study is to report a reduction in the thickness of the ganglion cell complex (GCC) after vitrectomy with internal limiting membrane (ILM) peeling in eyes with idiopathic macular hole (MH).

METHODS

Twenty-eight consecutive eyes with an idiopathic MH treated by vitrectomy with ILM peeling were studied. All eyes had an intravitreal injection of indocyanine green to make the ILM more visible. The best-corrected visual acuity (BCVA), GCC thickness measured by spectral domain optical coherence tomography, and retinal sensitivity measured by microperimetry were determined before and at 3 and 6 months after the vitrectomy.

RESULTS

The MH in all eyes was closed after the initial surgery. The BCVA was significantly improved at 3 and 6 months (P<0.001 and P<0.001, respectively). The thickness of the GCC was significantly reduced at 3 and 6 months postoperatively (P<0.001 and P<0.001, respectively). The GCC thickness was significantly correlated with the retinal sensitivity in the central 10 degrees at 6 months (r=0.55, P=0.004).

CONCLUSION

A reduction of the GCC thickness was observed after vitrectomy with ILM peeling for idiopathic MH.