Mechanism of piR-1245/PIWI-like protein-2 regulating Janus kinase-2/signal transducer and activator of transcription-3/vascular endothelial growth factor signaling pathway in retinal neovascularization.

Inhibiting retinal neovascularization is the optimal strategy for the treatment of retina-related diseases, but there is currently no effective treatment for retinal neovascularization. P-element-induced wimpy testis (PIWI)-interacting RNA (piRNA) is a type of small non-coding RNA implicated in a variety of diseases. In this study, we found that the expression of piR-1245 and the interacting protein PIWIL2 were remarkably increased in human retinal endothelial cells cultured in a hypoxic environment, and cell apoptosis, migration, tube formation and proliferation were remarkably enhanced in these cells. Knocking down piR-1245 inhibited the above phenomena. After intervention by a p-JAK2 activator, piR-1245 decreased the expression of hypoxia inducible factor-1α and vascular endothelial growth factor through the JAK2/STAT3 pathway. For in vivo analysis, 7-day-old newborn mice were raised in 75 ± 2% hyperoxia for 5 days and then piR-1245 in the retina was knocked down. In these mice, the number of newly formed vessels in the retina was decreased, the expressions of inflammation-related proteins were reduced, the number of apoptotic cells in the retina was decreased, the JAK2/STAT3 pathway was inhibited, and the expressions of hypoxia inducible factor-1α and vascular endothelial growth factor were decreased. Injection of the JAK2 inhibitor JAK2/TYK2-IN-1 into the vitreous cavity inhibited retinal neovascularization in mice and reduced expression of hypoxia inducible factor-1α and vascular endothelial growth factor. These findings suggest that piR-1245 activates the JAK2/STAT3 pathway, regulates the expression of hypoxia inducible factor-1α and vascular endothelial growth factor, and promotes retinal neovascularization. Therefore, piR-1245 may be a new therapeutic target for retinal neovascularization.

Three-year results of small incision lenticule extraction and wavefront-guided femtosecond laser-assisted laser in situ keratomileusis for correction of high myopia and myopic astigmatism.

AIM: To compare and calculate the 3-year refractive results, higher-order aberrations (HOAs), contrast sensitivity (CS) and dry eye parameters after small incision lenticule extraction (SMILE) and wavefront-guided femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) for correction of high myopia and myopic astigmatism. METHODS: In this prospective, non-randomized comparative study, 78 eyes with spherical equivalent (SE) of -8.11±1.09 diopters (D) received a SMILE surgery, and 65 eyes with SE of -8.05±1.12 D received a wavefront-guided FS-LASIK surgery with the VisuMax femtosecond laser (Carl Zeiss Meditec, Jena, Germany) for flap cutting. Visual acuity, manifest refraction, CS, HOAs, ocular surface disease index (OSDI) and tear break-up time (TBUT) were evaluated during a 3-year follow-up. RESULTS: The difference of uncorrected distance visual acuity (UDVA) postoperatively was achieved at 1mo and at 3mo, whereas the difference of the mean UDVA between two groups at 3y were not statistically significant (t=-1.59, P=0.13). The postoperative change of SE was 0.89 D in the FS-LASIK group (t=5.76, P=0.00), and 0.14 D in the SMILE group (t=0.54, P=0.59) from 1mo to 3y after surgery. At 3-year postoperatively, both HOAs and spherical aberrations in the SMILE group were obviously less than those in the FS-LASIK group (P=0.00), but the coma root mean square (RMS) was higher in the SMILE group (0.59±0.26) than in the FS-LASIK group (0.29±0.14, P=0.00). The mesopic CS values between two groups were not statistically significant at 3y postoperatively. Compared with the FS-LASIK group, lower OSDI scores and longer TBUT values were found in the SMILE group at 1mo and 3mo postoperatively. With regard to safety, no eye lost any line of CDVA in both groups at 3y after surgery. CONCLUSION: Both SMILE and wavefront-guided FS-LASIK procedures provide good visual outcomes. Both procedures are effective and safe, but SMILE surgery achieve more stable long-term refractive outcome and better control of early postoperative dry eye as compared to FS-LASIK.

Efficacy, safety, predictability, aberrations and corneal biomechnical parameters after SMILE and FLEx: Meta-analysis.

AIM: To identify possible differences of efficacy, safety, predictability, higher-order aberrations and corneal biomechnical parameters after small-incision lenticule extraction (SMILE) and femtosecond lenticule extraction (FLEx). METHODS: A systematic literature retrieval was conducted in Medline, Embase and the Cochrane Library, up to October, 2015. The included studies were subject to a Meta-analysis. Comparison between SMILE and FLEx was measured as pooled odds ratio (OR) or weighted mean differences (WMD). Of 95% confidence intervals (CI) were used to analyze data. RESULTS: A total of seven studies were included. Firstly, there were no differences in uncorrected distance visual acuity (UDVA) 20/20 or better (OR, 1.37; 95% CI, 0.69 to 2.69; P=0.37) and logMAR UDVA (WMD, -0.02; 95% CI, -0.05 to 0.01; P=0.17) after SMILE versus FLEx. We found no differences in corrected distance visual acuity (CDVA) unchanged (OR, 0.98; 95% CI, 0.46 to 2.11; P=0.97) and logMAR CDVA (WMD, -0.00; 95% CI, -0.01 to 0.01; P=0.90) either. Secondly, we found no differences in refraction within ±1.00 D (OR, 0.98; 95% CI, 0.13 to 7.28; P=0.99) and ±0.50 D (OR, 1.62; 95% CI, 0.62 to 4.28; P=0.33) of target postoperatively. Thirdly, for higher-order aberrations, we found no differences in the total higher-order aberrations (WMD, -0.04; 95% CI, -0.09 to 0.01; P=0.14), coma (WMD, -0.04; 95% CI, -0.09 to 0.01; P=0.11), spherical (WMD, 0.01; 95% CI, -0.02 to 0.03; P=0.60) and trefoil (WMD, -0.00; 95% CI, -0.04 to 0.03; P=0.76). Furthermore, for corneal biomechanical parameters, we also found no differences (WMD, 0.08; 95% CI, -0.17 to 0.33; P=0.54) after SMILE versus FLEx. CONCLUSION: There are no statistically differences in efficacy, safety, predictability, higher-order aberrations and corneal biomechnical parameters postoperative between SMILE and FLEx.

Comparison of the femtosecond laser and mechanical microkeratome for flap cutting in LASIK.

AIM: To compare refractive results, higher-order aberrations (HOAs), contrast sensitivity and dry eye after laser in situ keratomileusis (LASIK) performed with a femtosecond laser versus a mechanical microkeratome for myopia and astigmatism. METHODS: In this prospective, non-randomized study, 120 eyes with myopia received a LASIK surgery with the VisuMax femtosecond laser for flap cutting, and 120 eyes received a conventional LASIK surgery with a mechanical microkeratome. Flap thickness, visual acuity, manifest refraction, contrast sensitivity function (CSF) curves, HOAs and dry-eye were measured at 1wk; 1, 3, 6mo after surgery. RESULTS: At 6mo postoperatively, the mean central flap thickness in femtosecond laser procedure was 113.05±5.89 µm (attempted thickness 110 µm), and 148.36±21.24 µm (attempted thickness 140 µm) in mechanical microkeratome procedure. An uncorrected distance visual acuity (UDVA) of 4.9 or better was obtained in more than 98% of eyes treated by both methods, a gain in logMAR lines of corrected distance visual acuity (CDVA) occurred in more than 70% of eyes treated by both methods, and no eye lost ≥1 lines of CDVA in both groups. The difference of the mean UDVA and CDVA between two groups at any time post-surgery were not statistically significant (P>0.05). The postoperative changes of spherical equivalent occurred markedly during the first month in both groups. The total root mean square values of HOAs and spherical aberrations in the femtosecond treated eyes were markedly less than those in the microkeratome treated eyes during 6mo visit after surgery (P<0.01). The CSF values of the femtosecond treated eyes were also higher than those of the microkeratome treated eyes at all space frequency (P<0.01). The mean ocular surface disease index scores in both groups were increased at 1wk, and recovered to preoperative level at 1mo after surgery. The mean tear breakup time (TBUT) of the femtosecond treated eyes were markedly longer than those of the microkeratome treated eyes at postoperative 1, 3mo (P<0.01). CONCLUSION: Both the femtosecond laser and the mechanical microkeratome for LASIK flap cutting are safe and effective to correct myopia, with no statistically significant difference in the UDVA, CDVA during 6mo follow-up. Refractive results remained stable after 1mo post-operation for both groups. The femtosecond laser may have advantages over the microkeratome in the flap thickness predictability, fewer induced HOAs, better CSF, and longer TBUT.

[Cytokine expression in murine cornea tissue during recurrent herpetic stromal keratitis].

OBJECTIVE: To investigate the expression of cytokine in CD(4)(+) T helper type 1 (Th1) and T helper type 2 (Th2) cells in murine cornea during recurrent herpetic stromal keratitis (HSK) and its relationship with the HSK. METHODS: Seven weeks after corneal inoculation with HSV-1, the eyes of latently infected BALB/c mice were irradiated by UV-B and examined for the signs of inflammation and viral reactivation. The corneas of six mice with recurrent stromal disease and six controls were examined to detect the content of Th1 type cytokines (IFN-gamma and IL-12) and Th2 type cytokines (IL-4 and IL-10) on days 0, 3, 7, 10, 14, 21 and 28 after irradiation. RESULTS: Peak of the inflammation process of HSK, manifested by stromal opacification, occurred 7-14 days after viral reactivation in latently infected mice. In semi-quantitative RT-PCR analyses, IFN-gamma, IL-12 p40, IL-10 and IL-4 mRNA were expressed before and during the clinical course of recurrent HSK. The highest expression of IFN-gamma and IL-10 was revealed during the occurrence and development of corneal inflammation (3 -14 days after the reactivation of virus) with a decline at the recovering process (after 14 days). The expression of IFN-gamma and IL-10 was co-related with the degree of corneal opacification. Large amounts of IL-12 p40 mRNA were detected in the cornea 3 days after the virus reactivation and maintained over the whole course of observation. IL-4 levels increased at 3-14 days after the reactivation of virus and declined after day 14. CONCLUSIONS: Th1 and Th2 cytokines present together throughout the course of the inflammatory process accompanying recurrent corneal HSV-1 infection, which is likely associated with a memory response to viral antigens. The expression of IL-10 mRNA parallels with the expression of IFN-gamma and is co-related with the degree of corneal inflammation. The damage and repair of corneal tissue in recurrent HSK may depend upon the balance between the destructive cytokines and protective cytokines at the site of virus reactivation.

[Inhibition by CTLA-4Ig on herpetic stromal keratitis in a murine model].

OBJECTIVE: To investigate the inhibition by CTLA-4Ig on herpetic stromal keratitis (HSK). METHODS: BALB/c mice infected with HSV-1 Mckrae strain by corneal scarification were injected intraperitoneally with murine CTLA-4Ig given on days 0, +2, +4 after the infection. The effects of CTLA-4Ig on HSK were evaluated. RESULTS: As measured by flow cytometry, in the mice treated with CTLA-4Ig, 81.6% of CD4(+)T cells and 67.9% of CD8(+)T cells were reduced. CTLA-4Ig halted the onset of HSK, reduced the corneal stromal opacification of HSK, prevented extensive cellular infiltration in cornea, impaired the delayed type hypersensitivity and inhibited splenocytes producing Th1 cytokines. CONCLUSIONS: The results provide evidence that blockade of B7:CD28/CTLA-4 costimulation by CTLA-4Ig can inhibit the proliferation of T cells and Th1 response and impair onset and severity of HSK.

[Suppression effects of interleukin-10 on mouse herpetic stromal keratitis].

OBJECTIVE: To investigate the role of interleukin-10 (IL-10) in herpetic stromal keratitis (HSK). METHODS: Eighty BALB/c mice were divided into two groups and infected with HSV-1 Mckrae strain by corneal scarification. Murine rIL-10 (20 ng/ml) was inoculated intracorneally 6 h before and again on days 0, 2 and 4 after topical HSV-1 corneal infection. rIL-10 (500 ng) was given intraperitoneally in treated mice simultaneously. The same amount of saline was injected into the control mice. The effects of IL-10 on HSK were evaluated. RESULTS: In the IL-10-treated animals, the onset of HSK was delayed, corneal stromal opacification and neovascularization were reduced, extensive cellular infiltrates in the cornea were prevented and delayed type hypersensitivity (DTH) was weakened. Examination of pro-inflammatory cytokine levels in the cornea 10 days after the infection revealed that the amounts of IL-2 and IL-6 were lower than those found in the controls. IL-10 did not suppress the viral replication nor did it eliminate the virus from IL-10-treated eyes, as compared with the controls. CONCLUSIONS: IL-10 treatment can suppress DTH responsiveness and the production of certain cytokines by corneal cells. It delays the onset and decreases the severity of HSK.