Altered fatty acid distribution in lysosome-associated membrane protein-2 deficient mice.

Lysosome-associated membrane protein-2 (LAMP2) deficiency causes the human Danon disease and represents a lysosomal dysfunction because of its pivotal role in regulating autophagy and lysosome biogenesis. LAMP2-deficient mice exhibit a spectrum of phenotypes, including cardioskeletal myopathy, mental retardation, and retinopathy, similar to those observed in patients with Danon disease. Its pathology is thought to involve altered energy metabolism and lipid dysregulation; however, the lipidomic profiles of LAMP2-deficient animals have not been investigated. In this study, we investigated lipid alterations in LAMP2 KO mice tissues, including those of the liver, plasma, and retina, using liquid chromatography-mass spectrometry. Our results revealed significantly increased free fatty acid (FFA) levels and decreased in triglyceride (TG) levels in LAMP2 KO liver tissues at three and six months. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) species significantly decreased in LAMP2 KO mice livers at six months. Similarly, plasma TG and PC/PE levels decreased in LAMP2 KO mice. In contrast, plasma FFA levels were significantly lower in LAMP2 KO mice. Retina FFA levels were elevated in LAMP2 KO mice, accompanied by a partial decrease in PC/PE at six months. In summary, FFA levels increased in several tissues but not in the LAMP2 KO mice plasma, suggesting the potential consumption of FFA as an energy source in the peripheral tissues. The depletion of TG and PC/PE accelerated with age, suggesting an underlying age-dependent energy crisis condition. Our findings underscore the dysregulated distribution of fatty acids in LAMP2-deficient animals and provide new mechanistic insights into the pathology of Danon disease.

Comparison of Microperimetry and Static Perimetry for Evaluating Macular Function and Progression in Retinitis Pigmentosa.

Purpose: To compare the usefulness of microperimetry and static automated perimetry in patients with retinitis pigmentosa (RP), using macular anatomical metrics as a reference. Design: Prospective observational study. Participants: Forty-eight eyes of 48 patients with RP in Kyushu University Hospital who underwent microperimetry-3 (MP-3) and Humphrey Field Analyzer (HFA) 10-2 testing ≥3 times during ≥2 years were included. Methods: Macular anatomy (ellipsoid zone [EZ] length) was assessed by OCT, and macular function was assessed by MP-3 (mean retinal sensitivity at radii 2°, 4°, and 8°) and HFA10-2 program (mean retinal sensitivity at radii 2°, 4°, and 8°). Correlations between functional and anatomical parameters were analyzed cross sectionally at baseline and longitudinally by comparing the rate of progression. Main Outcome Measures: Correlation coefficients between anatomical and functional metrics. Results: The mean age at baseline was 50.1 ± 12.3 years, and the mean follow-up period was 2.8 ± 0.7 years. At baseline, EZ length was significantly correlated with MP-3 mean retinal sensitivity at radii 2°, 4°, and 8° (Spearman's ρ = 0.65, 0.84, 0.89; all P < 0.005) and HFA10-2 mean retinal sensitivity at radii 2°, 4°, and 8° (Spearman's ρ = 0.61, 0.73, 0.78; all P < 0.005). Longitudinal analysis showed that the slope of EZ length (-88.92 µm/year) was significantly correlated with the slope of MP-3 retinal sensitivity at 8° radius (-0.62 decibels [dB]/year; Spearman's ρ = 0.31, P=0.03) and the slope of HFA retinal sensitivity at 8° radius (-0.60 dB/year; Spearman's ρ = 0.43, P < 0.005). Conclusions: Both MP-3 and HFA values were cross sectionally well-correlated with EZ length in patients with patients; however, these associations became weaker in the longitudinal analysis. This highlights the need for researchers to explore additional or more sensitive parameters to better monitor RP progression. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Ocular and Serum Profiles of Inflammatory Molecules Associated With Retinitis Pigmentosa.

Purpose: To investigate the profiles and correlations between local and systemic inflammatory molecules in patients with retinitis pigmentosa (RP). Methods: The paired samples of aqueous humor and serum were collected from 36 eyes of 36 typical patients with RP and 25 eyes of age-matched patients with cataracts. The concentration of cytokines/chemokines was evaluated by a multiplexed immunoarray (Q-Plex). The correlations between ocular and serum inflammatory molecules and their association with visual function were analyzed. Results: The aqueous levels of IL-6, Eotaxin, GROα, I-309, IL-8, IP-10, MCP-1, MCP-2, RANTES, and TARC were significantly elevated in patients with RP compared to controls (all P < 0.05). The detection rate of aqueous IL-23 was higher in patients with RP (27.8%) compared with controls (0%). In patients with RP, Spearman correlation test demonstrated positive correlations for IL-23, I-309, IL-8, and RANTES between aqueous and serum expression levels (IL-23: ⍴ = 0.8604, P < 0.0001; I-309: ρ = 0.4172, P = 0.0113; IL-8: ρ = 0.3325, P = 0.0476; RANTES: ρ = 0.6685, P < 0.0001). In addition, higher aqueous IL-23 was associated with faster visual acuity loss in 10 patients with RP with detected aqueous IL-23 (ρ = 0.4119 and P = 0.0264). Multiple factor analysis confirmed that aqueous and serum IL-23 were associated with visual acuity loss in patients with RP. Conclusions: These findings suggest that ocular and systemic inflammatory responses have a close interaction in patients with RP. Further longitudinal studies with larger cohorts are needed to explore the correlation between specific inflammatory pathways and the progression of RP. Translational Relevance: This study demonstrates the local-systemic interaction of immune responses in patients with RP.

Relationships between causative genes and epiretinal membrane formation in Japanese patients with retinitis pigmentosa.

PURPOSE: To investigate the relationships between macular complications and causative genes frequently found in Japanese patients with retinitis pigmentosa (RP). METHODS: In the retrospective and observational study, we analyzed the data of 75 patients with RP (EYS-RP: 42 patients; USH2A-RP: 19 patients; RHO-RP: 14 patients) who were followed-up at Kyushu University Hospital and whose causative genes had been identified. Macular complications including epiretinal membrane (ERM), macular edema (ME), and macular hole (MH) were evaluated using optical coherence tomography and fundus photography. Main outcome was the proportion of macular complications. RESULTS: The proportion of ERM was 35.7% in the EYS group, 10.5% in the USH2A group and 14.3% in the RHO group. The proportion of ME was 7.1% in the EYS group, 5.3% in the USH2A group and 14.3% in the RHO group, and that of MH was 2.4% in the EYS group, 5.3% in the USH2A group and 0% in the RHO group. In the EYS group, the proportion of ERM was relatively higher (p = 0.06), and the presence of EYS was significantly associated with a higher age- and sex-adjusted OR for ERM (OR = 5.67, 95% CI = 1.59-25.20). There was no significant difference in the proportion of MH or ME among causative genes. CONCLUSIONS: EYS causative gene may be associated with higher rate of ERM complication in RP.

Disease-specific variant interpretation highlighted the genetic findings in 2325 Japanese patients with retinitis pigmentosa and allied diseases.

BACKGROUND: As gene-specific therapy for inherited retinal dystrophy (IRD) advances, unified variant interpretation across institutes is becoming increasingly important. This study aims to update the genetic findings of 86 retinitis pigmentosa (RP)-related genes in a large number of Japanese patients with RP by applying the standardised variant interpretation guidelines for Japanese patients with IRD (J-IRD-VI guidelines) built upon the American College of Medical Genetics and Genomics and the Association for Molecular Pathology rules, and assess the contribution of these genes in RP-allied diseases. METHODS: We assessed 2325 probands with RP (n=2155, including n=1204 sequenced previously with the same sequencing panel) and allied diseases (n=170, newly analysed), including Usher syndrome, Leber congenital amaurosis and cone-rod dystrophy (CRD). Target sequencing using a panel of 86 genes was performed. The variants were interpreted according to the J-IRD-VI guidelines. RESULTS: A total of 3564 variants were detected, of which 524 variants were interpreted as pathogenic or likely pathogenic. Among these 524 variants, 280 (53.4%) had been either undetected or interpreted as variants of unknown significance or benign variants in our earlier study of 1204 patients with RP. This led to a genetic diagnostic rate in 38.6% of patients with RP, with EYS accounting for 46.7% of the genetically solved patients, showing a 9% increase in diagnostic rate from our earlier study. The genetic diagnostic rate for patients with CRD was 28.2%, with RP-related genes significantly contributing over other allied diseases. CONCLUSION: A large-scale genetic analysis using the J-IRD-VI guidelines highlighted the population-specific genetic findings for Japanese patients with IRD; these findings serve as a foundation for the clinical application of gene-specific therapies.

A case of primary orbital liposarcoma with dedifferentiated transformation from a well-differentiated form.

Purpose: Primary orbital liposarcomas are rare. To the best of our knowledge, only four cases of primary dedifferentiated liposarcomas of the orbit have been reported. Furthermore, there have been no reports of primary orbital liposarcomas transitioning from a highly differentiated to a dedifferentiated form. Here, we report a case of primary orbital liposarcoma that was well-differentiated at the time of initial resection at our hospital but had dedifferentiated on recurrence 10 years after the initial resection. Observations: The patient was diagnosed with an inflammatory mass after an initial tumor resection by a previous physician at age 52. Thereafter, there were four recurrences (first to fourth recurrences), and the patient underwent five surgeries and radiotherapy. For the fifth recurrence, he first visited our hospital at age 64 and was diagnosed with a well-differentiated liposarcoma after undergoing tumor resection. When the tumor recurred 9 years later (the sixth recurrence), it was well-differentiated. When the tumor recurred (the seventh recurrence) six months after surgery at the age of 73 years, the patient underwent orbital exenteration because of rapid tumor growth, and pathological examination showed that the tissue had changed to a dedifferentiated liposarcoma. Conclusions and Importance: Primary well-differentiated orbital liposarcoma may transform to a dedifferentiated form over time. The risk of dedifferentiation at recurrence should be considered in developing a treatment plan, even if the initial pathology is a well-differentiated liposarcoma.

Circulating inflammatory monocytes oppose microglia and contribute to cone cell death in retinitis pigmentosa.

Retinitis pigmentosa (RP) is an intractable inherited disease that primarily affects the rods through gene mutations followed by secondary cone degeneration. This cone-related dysfunction can lead to impairment of daily life activities, and ultimately blindness in patients with RP. Paradoxically, microglial neuroinflammation contributes to both protection against and progression of RP, but it is unclear which population(s) - tissue-resident microglia and/or peripheral monocyte-derived macrophages (mφ) - are implicated in the progression of the disease. Here we show that circulating blood inflammatory monocytes (IMo) are key effector cells that mediate cone cell death in RP. Attenuation of IMo and peripherally engrafted mφ by Ccl2 deficiency or immune modulation via intravenous nano-particle treatment suppressed cone cell death in rd10 mice, an animal model of RP. In contrast, the depletion of resident microglia by a colony-stimulating factor 1 receptor inhibitor exacerbated cone cell death in the same model. In human patients with RP, IMo was increased and correlated with disease progression. These results suggest that peripheral IMo is a potential target to delay cone cell death and prevent blindness in RP.

Genotype and Long-term Clinical Course of Bietti Crystalline Dystrophy in Korean and Japanese Patients.

PURPOSE: To investigate the genotype and long-term clinical phenotype of patients with Bietti crystalline dystrophy (BCD) in Korea and Japan. DESIGN: Retrospective case series. PARTICIPANTS: We analyzed 62 patients with clinical features of BCD who harbor pathogenic biallelic CYP4V2 variants in their homozygote or compound heterozygote. METHODS: Data were collected from patient charts, including age, best-corrected visual acuity (BCVA), Goldmann perimetry results, fundus photography, OCT findings, fundus autofluorescence results, and electroretinography findings. We compared the clinical course of the patients with homozygous c.802-8_810de117insGC [exon7del], the most common mutation in the East Asian population, with those of the patients with other genotypes. MAIN OUTCOME MEASURES: Best-corrected visual acuity, visual field (VF), and their changes during follow-up. RESULTS: The mean age at the first visit was 55.2 years, with a mean follow-up of 7.1 years. The mean BCVAs at the first and last visits were 0.28 logarithm of the minimum angle of resolution (logMAR) and 0.89 logMAR, respectively. In genetic testing, c.802-8_810de117insGC was detected in 86 of 124 alleles of the patients, and 36 patients were homozygous for this mutation. The age, BCVA, VF area, central foveal thickness, and abnormal hypoautofluorescent area at either the first or last visit were not different between the exon7del homozygotes and the others. The mean BCVA changes per year were 0.089 logMAR in the exon7del homozygotes and 0.089 logMAR in the others. An age- and gender-adjusted linear regression analysis showed no association between the exon7del homozygote status and the rate of vision loss. Characteristic crystalline deposits in the posterior pole were generally observed in younger patients and disappeared over time along with progressive retinochoroidal atrophy. CONCLUSIONS: Patients with BCD and a homozygote for c.802-8_810de117insGC accounted for more than 50% of this cohort of Korean and Japanese patients, and the clinical effect of this deleterious variant was not severe in the spectrum of CYP4V2 retinopathy.

Structures of filum terminale and characteristics of ependymal cells of its central canal in rats.

The filum terminale (FT) is a potential source of ependymal cells for transplantation. The present study was performed to clarify the characteristics of ependymal cells of the central canal (CC) of the FT in rats. The FT was a thin strand continuous with the conus medullaris (CM), a caudal end of the main spinal cord, situated at the L3-4 level in adult rats. The border between the CM and FT was not visible, but could be defined as the site where the strand was as thin as its more caudal segment. While the CM contained an appreciable amount of white and grey matter associated with the CC at its center, the FT had no or only a negligible amount of such spinal cord parenchymal tissue. The FT was tracked ca. 4 cm from the site defined above to the level of S4-5 in adult rats. The rostral part of the FT (FTI) included within the cauda equina is exposed to cerebrospinal fluid, whereas the more caudal part (FTE) was surrounded by a dense layer of connective tissue. Almost all ependymal cells were immunostained for Sox2, Sox9, FoxJ1, and CD133, generally recognized immunochemical markers for ependymal cells of the CC in the spinal cord. Ependymal cells of the CC of FT exhibited almost the same structural and immunohistochemical characteristics as those of the CC of the main spinal cord. Ependymal cells of FTI covered by a thin layer of connective tissue are considered appropriate for transplantation.

Effects of Intrathecal Injection of the Conditioned Medium from Bone Marrow Stromal Cells on Spinal Cord Injury in Rats.

Bone marrow stromal cells (BMSCs) have been studied for the treatment of spinal cord injury (SCI). In previous studies, we showed that the transplantation of BMSCs, even though they disappeared from the host spinal cord within 1-3 weeks after transplantation, improved locomotor behaviors and promoted axonal regeneration. This result led to the hypothesis that BMSCs might release some neurotrophic factors effective for the treatment of SCI. The present study examined this by injecting the conditioned medium (CM) of BMSCs to treat SCI in rats. The spinal cord was contusion-injured, followed immediately by continuous injection for 2 weeks of the CM of BMSCs through the cerebrospinal fluid via the 4th ventricle using an Alzet osmotic pump. Locomotor behaviors evaluated by the Basso-Beattie-Bresnahan score were markedly improved in the CM-injection group, compared with the control group, at 1 to 4 weeks post-injection. The contusion-injured site of the spinal cord was identified as an astrocyte-devoid area, which contained no astrocytes but was filled with collagen matrices and empty cavities of various sizes. Collagen matrices contained type I collagen and laminin. Numerous axons extended through the collagen matrices of the astrocyte-devoid area. Axons were surrounded by Schwann cells, exhibiting the same morphological characteristics as peripheral nerve fibers. The density of axons extending through the astrocyte-devoid area was higher in the CM-injection group, compared with the control group. CM injection had beneficial effects on locomotor improvements and tissue repair, including axonal regeneration, meaning that the BMSC-CM stimulated the intrinsic ability of the spinal cord to regenerate. Activation of the intrinsic ability of the spinal cord to regenerate by the injection of neurotrophic factors such as BMSC-CM is considered to be a safe and preferable method for the clinical treatment of SCI.