成熟哺乳動物網膜の神経突起再生と神経栄養因子

近年,神経の分化や生存維持などにかかわる種々の因子が同定され,そのなかで特に神経栄養因子と呼ばれる一群の物質が様々な効果を神経に及ぼしていることがわかってきた.私達は視神経の再生を目標としてその一助となる薬剤の評価をするための実験系を組み立て,神経栄養因子の評価を行った.成熟ラットの網膜を用い,コラーゲンゲル中で網膜神経節細胞の組織培養を行った.培養液は無血清培養液を用い,その中に各種神経栄養因子nerve growth factor(NGF),brain-derived neurotrophic factor(BDNF),neurotrophin-3(NT-3),neurotrophin-4(NT-4)およびciliary neurotrophic factor(CNTF)を添加した.その後,再生してくる網膜神経節細胞の神経突起数を経時的に計測,比較することにより,各神経栄養因子が網膜神経節細胞の神経突起再生に与える効果を評価した.その結果,培養2日目から単離した網膜神経節細胞より再生神経突起が伸長するのが観察された.免疫組織染色によりこれらは中枢神経である網膜神経節細胞の再生神経突起であることがわかった.この再生神経突起の本数を比較したところ,BDNFおよびNT-4添加培養液では培養期間を通して神経突起の再生促進効果がみられた.NGF添加培養液では,培養早期には促進効果がみられたが,徐々にその効果は減弱した.NT-3およびCNTF添加培養液では,神経突起再生促進効果はみられなかった.BDNFを培養初期に投与したものと培養中期以降に投与したものを比較検討したところBDNFは培養初期に投与された時に神経突起再生促進効果が比較的大きいことが示唆された.Recent studies identified different factors involved in differentiation or survival of nerve cells. A particular group of substances, I.e., neurotrophic factors, has been found to affect nerve cells in various ways. Targeting the regeneration of optic nerve cells, we developed an assay system to evaluate drugs that support optic nerve regeneration and evaluated the neurotrophic factors. Retinal ganglion cells were removed from mature rats and incubated in collagen gels. A serum-free culture medium was spiked with various nerve growth factors (NGFs) including brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), neurotrophin-4 (NT-4), and ciliary neurotrophic factor (CNTF). Regenerated neurites were counted within retinal ganglion cells and the number was compared with baseline values to evaluate the effect of each nerve growth factor on neurite regeneration in retinal ganglion cells. Regenerated neurites extended from isolated retinal ganglion cells from Day 2 of incubation. Immunohistological staining revealed that these regenerated neurites originated from retinal ganglion cells that are a part of the central nerves. Comparing the number of regenerated neurites, neurite regeneration was stimulated throughout the incubation period in culture media spiked with BDNF or NT-4. In the NGF-added medium, regeneration was promoted soon after the start of incubation, but the effect gradually diminished. In media spiked with NT-3 or CNTF, neurite regeneration was not stimulated. Comparing the effect of BDNF addition between early and intermediate/late stages of incubation, neurite regeneration was more stimulated extent when the medium was spiked with BDNF soon after the start of incubation

Common Variants in the COL4A4 Gene Confer Susceptibility to Lattice Degeneration of the Retina

Lattice degeneration of the retina is a vitreoretinal disorder characterized by a visible fundus lesion predisposing the patient to retinal tears and detachment. The etiology of this degeneration is still uncertain, but it is likely that both genetic and environmental factors play important roles in its development. To identify genetic susceptibility regions for lattice degeneration of the retina, we performed a genome-wide association study (GWAS) using a dense panel of 23,465 microsatellite markers covering the entire human genome. This GWAS in a Japanese cohort (294 patients with lattice degeneration and 294 controls) led to the identification of one microsatellite locus, D2S0276i, in the collagen type IV alpha 4 (COL4A4) gene on chromosome 2q36.3. To validate the significance of this observation, we evaluated the D2S0276i region in the GWAS cohort and in an independent Japanese cohort (280 patients and 314 controls) using D2S0276i and 47 single nucleotide polymorphisms covering the region. The strong associations were observed in D2S0276i and rs7558081 in the COL4A4 gene (Pc = 5.8×10−6, OR = 0.63 and Pc = 1.0×10−5, OR = 0.69 in a total of 574 patients and 608 controls, respectively). Our findings suggest that variants in the COL4A4 gene may contribute to the development of lattice degeneration of the retina

Pars plana vitrectomy combined with penetrating keratoplasty and transscleral-sutured intraocular lens implantation in complex eyes: a case series

Background The aim of this study was to evaluate the clinical outcomes of pars plana vitrectomy (PPV) combined with penetrating keratoplasty (PKP) and transscleral-sutured intraocular lens (IOL) implantation (IOL-suture) in complex eyes. Methods In this prospective, consecutive interventional case series, patients who underwent PKP combined with PPV and IOL implantation from July 2014 to March 2018 at Yokohama Minami Kyosai Hospital were enrolled. The postoperative best corrected visual acuity (BCVA) (converted to logarithm of the minimal angle of resolution [logMAR] units), intraocular pressure (IOP, mmHg), endothelial cell density (ECD, cells/mm(2)), graft survival, complications, astigmatism, and spherical equivalent (dioptres [D]) were evaluated. Results This study included 11 eyes of 11 patients (three females and eight males; mean age, 61.8 +/- 13.9 years) with an injury (n = 6) or bullous keratopathy (n = 5). The BCVA significantly improved from 1.50 +/- 0.66 logMAR preoperatively to 0.78 +/- 0.59 logMAR (p < 0.001) postoperatively. The baseline ECD significantly decreased from 2396 +/- 238 cells/mm(2)preoperatively to 1132 +/- 323 cells/mm(2)(p < 0.001) postoperatively. Despite two rejection episodes, graft survival rates were 100%. The mean follow-up period was 38.0 +/- 20.5 months. Two patients required combined glaucoma surgery, and three patients underwent subsequent glaucoma surgery. Postoperative astigmatism and spherical equivalent were 3.9 +/- 3.2 D and 0.29 +/- 2.18 D, respectively. Conclusion The combination of PKP, PPV, and IOL-suture implantation could be a safe and effective approach for eyes requiring anterior segment surgery; however, these eyes are associated with a higher incidence of glaucoma surgery

RIG-I functions as a dual effector against HBV

Host innate recognition triggers key immune responses for viral elimination. The sensing mechanism of hepatitis B virus (HBV), a DNA virus, and the subsequent downstream signaling events remain to be fully clarified. Here we found that type III but not type I interferons are predominantly induced in human primary hepatocytes in response to HBV infection, through retinoic acid-inducible gene-I (RIG-I)-mediated sensing of the 5'-ε region of HBV pregenomic RNA. In addition, RIG-I could also counteract the interaction of HBV polymerase (P protein) with the 5'-ε region in an RNA-binding dependent manner, which consistently suppressed viral replication. Liposome-mediated delivery and vector-based expression of this ε region-derived RNA in liver abolished the HBV replication in human hepatocyte-chimeric mice. These findings identify an innate recognition mechanism by which RIG-I dually functions as an HBV sensor activating innate signaling and to counteract viral polymerase in human hepatocytes.Supplemental materials are available on the publisher's website

The Role of Endoscopic Ultrasound for Esophageal Varices

Esophageal varices are caused by the development of collateral circulation in the esophagus as a result of portal hypertension. It is important to administer appropriate preventive treatment because bleeding varices can be fatal. Esophageal varices have complex and diverse hemodynamics, and there are various variations for each case. Endoscopic ultrasound (EUS) can estimate the hemodynamics of each case. Therefore, observation by EUS in esophageal varices provides useful information, such as safe and effective treatment selection, prediction of recurrence, and appropriate follow-up after treatment. Although treatment for the esophagogastric varices can be performed without EUS imaging, understanding the local hemodynamics of the varices using EUS prior to treatment will lead to more safe and effective treatment. EUS observation is an indispensable tool for thorough variceal care