taurochenodeoxycholic-acid and Retinitis-Pigmentosa

Successful drug therapies for treating ocular diseases require effective concentrations of neuroprotective compounds maintained over time at the site of action. The purpose of this work was to assess the efficacy of intravitreal controlled delivery of tauroursodeoxycholic acid (TUDCA) encapsulated in poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres for the treatment of the retina in a rat model of retinitis pigmentosa. PLGA microspheres (MSs) containing TUDCA were produced by the O/W emulsion-solvent evaporation technique. Particle size and morphology were assessed by light scattering and scanning electronic microscopy, respectively. Homozygous P23H line 3 rats received a treatment of intravitreal injections of TUDCA-PLGA MSs. Retinal function was assessed by electroretinography at P30, P60, P90 and P120. The density, structure and synaptic contacts of retinal neurons were analyzed using immunofluorescence and confocal microscopy at P90 and P120. TUDCA-loaded PLGA MSs were spherical, with a smooth surface. The production yield was 78%, the MSs mean particle size was 23 μm and the drug loading resulted 12.5 ± 0.8 μg TUDCA/mg MSs. MSs were able to deliver the loaded active compound in a gradual and progressive manner over the 28-day in vitro release study. Scotopic electroretinografic responses showed increased ERG a- and b-wave amplitudes in TUDCA-PLGA-MSs-treated eyes as compared to those injected with unloaded PLGA particles. TUDCA-PLGA-MSs-treated eyes showed more photoreceptor rows than controls. The synaptic contacts of photoreceptors with bipolar and horizontal cells were also preserved in P23H rats treated with TUDCA-PLGA MSs. This work indicates that the slow and continuous delivery of TUDCA from PLGA-MSs has potential neuroprotective effects that could constitute a suitable therapy to prevent neurodegeneration and visual loss in retinitis pigmentosa.

Topics: Animals; Blindness; Delayed-Action Preparations; Disease Models, Animal; Electroretinography; Lactic Acid; Microspheres; Neuroprotective Agents; Particle Size; Photoreceptor Cells, Vertebrate; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Rats; Rats, Sprague-Dawley; Retina; Retinal Degeneration; Retinitis Pigmentosa; Taurochenodeoxycholic Acid

We explored the potential protective effects of tauroursodeoxycholic acid (TUDCA) on cone photoreceptor survival in a model of rapid retinal degeneration, the ß-Pde6 (rd1) (rd1) mouse model. We injected two strains of rd1 mice (B6.C3-Pde6b (rd1) Hps4(le)/J and C57BL/6J-Pde6b (rd1-2)/J mice) daily from postnatal day (P) 6 to P21 with TUDCA or vehicle. At P21, retinal function was evaluated with light-adapted electroretinography (ERG) and retinal structure was observed with plastic or frozen sections. TUDCA treatment partially preserved function and structure in B6.C3-Pde6b (rd1) Hps4(le)/J mice but only partially preserved structure in C57BL/6J-Pde6b (rd1-2)/J mice. Our results suggest a possible intervention for patients undergoing rapid retinal degeneration.

Topics: Animals; Cell Count; Disease Models, Animal; Electroretinography; Humans; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Photoreceptor Cells, Vertebrate; Protective Agents; Retina; Retinitis Pigmentosa; Species Specificity; Taurochenodeoxycholic Acid

To evaluate and compare the protective effect of tauroursodeoxycholic acid (TUDCA) on photoreceptor degeneration in different models of retinal degeneration (RD) in mice.. Bbs(M390R/M390R) mice were injected subcutaneously twice a week, from P40 to P120, and rd10 mice were injected every 3 days from P6 to P38 with TUDCA or vehicle (0.15 M NaHCO(3)). Rd1 and rd16 mice were injected daily from P6 to P30 with TUDCA or vehicle. Retinal structure and function were determined at multiple time points by electroretinography (ERG), optical coherence tomography (OCT), and histology.. The amplitude of ERG b-waves was significantly higher in TUDCA-treated Bbs1 and rd10 animals than in controls. Retinal thickness on OCT was slightly greater in treated Bbs1 animals than in the controls. Histologically, outer segments were preserved, and the outer nuclear layer was significantly thicker in the treated Bbs1 and rd10 mice than in the controls. Bbs1(M390R/M390R) mice developed less obesity than the control Bbs1(M390R/M390R) while receiving TUDCA. The Rd1 and rd16 mice showed no improvement with TUDCA treatment, and the rd1 mice did not have normal weight gain during treatment.. TUDCA treatment preserved ERG b-waves and the outer nuclear layer in Bbs1(M390R/M390R) mice, and prevented obesity assessed at P120. TUDCA treatment preserved ERG b-waves and the outer nuclear layer in the rd10 mice to P30. TUDCA is a prime candidate for treatment of humans with retinal degeneration, especially those with Bardet-Biedl syndrome, whom it may help not only with the vision loss, but with the debilitating obesity as well.

Topics: Animals; Bardet-Biedl Syndrome; Cholagogues and Choleretics; Disease Models, Animal; Electroretinography; Injections, Subcutaneous; Mice; Microtubule-Associated Proteins; Obesity; Retina; Retinal Degeneration; Retinitis Pigmentosa; Taurochenodeoxycholic Acid; Tomography, Optical Coherence

Retinitis pigmentosa (RP) is a progressive neurodegenerative disease resulting in blindness for which there is no current treatment. Although the members of the family of RP diseases differ in etiology, their outcomes are the same: apoptosis of rods and then by cones. Recently, the bile acid tauroursodeoxycholic acid (TUDCA) has been shown to have antiapoptotic properties in neurodegenerative diseases, including those of the retina. In this study the authors examined the efficacy of TUDCA on preserving rod and cone function and morphology at postnatal day 30 (P30) in the rd10 mouse, a model of RP.. Wild-type C57BL/6J and rd10 mice were systemically injected with TUDCA (500 mg/kg) every 3 days from P6 to P30 and were compared with vehicle (0.15 M NaHCO(3)). At P30, retinal function was measured with electroretinography, and morphologic preservation of the rods and cones was assessed with immunohistochemistry.. Dark-adapted electroretinographic (ERG) responses were twofold greater in rd10 mice treated with TUDCA than with vehicle, likewise light-adapted responses were twofold larger in TUDCA-treated mice than in controls at the brightest ERG flash intensities. TUDCA-treated rd10 retinas had fivefold more photoreceptors than vehicle-treated retinas. TUDCA treatments did not alter retinal function or morphology of wild-type mice when administered to age-matched mice.. TUDCA is efficacious and safe in preserving vision in the rd10 mouse model of RP when treated between P6 and P30. At P30, a developmental stage at which nearly all rods are absent in the rd10 mouse model of RP, TUDCA treatment preserved rod and cone function and greatly preserved overall photoreceptor numbers.

Topics: Animals; Apoptosis; Cell Count; Cell Nucleus; Cholagogues and Choleretics; Dark Adaptation; Disease Models, Animal; Electroretinography; Female; Fluorescent Antibody Technique, Indirect; In Situ Nick-End Labeling; Male; Mice; Mice, Inbred C57BL; Microscopy, Fluorescence; Photoreceptor Cells, Vertebrate; Retinitis Pigmentosa; Rod Opsins; Taurochenodeoxycholic Acid