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result(s) for
"Sakurai, Yutaka"
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Association between aqueous humor and vitreous fluid levels of Th17 cell-related cytokines in patients with proliferative diabetic retinopathy
2017
Inflammation is known to be involved in the progression of diabetic retinopathy. We have recently reported that vitreous levels of IL-4, IL-17A, IL-22, IL-31, and TNFα are higher than the respective serum levels in proliferative diabetic retinopathy (PDR) patients, and that vitreous levels of these cytokines are higher in PDR than in other non-inflammatory vitreoretinal diseases or uveitis associated with sarcoidosis. In the present study, we investigated inflammatory cytokines including Th17 cell-related cytokines in aqueous humor samples obtained from eyes with PDR, and analyzed the association between the aqueous humor and vitreous fluid levels of individual cytokines. The study group consisted of 31 consecutive type 2 diabetic patients with PDR who underwent cataract surgery and vitrectomy for vitreous hemorrhage and/or tractional retinal detachment. Undiluted aqueous humor was collected during cataract surgery, and then vitreous fluid was obtained using a 25G vitreous cutter inserted into the mid-vitreous cavity at the beginning of vitrectomy. IL-1β, IL-4, IL-6, IL-10, IL-17A, IL-17F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, IFN-γ, soluble CD40 ligand (sCD40L), and TNFα levels in the aqueous humor and vitreous fluid were measured using a beads-array system. Although IL-17A was detected in the aqueous humor of eyes with PDR and the level correlated with IL-17A level in the vitreous fluid, both percent detectable and level of IL-17A in the aqueous humor were significantly lower than those in the vitreous fluid. Vitreous IL-17A level was related significantly to IL-10, IL-22, and TNFα levels in aqueous humor as well as in vitreous fluid, On the other hand, aqueous IL-17A level was not related significantly to aqueous or vitreous levels of IL-10, IL-22 or TNFα level. The present study demonstrated that IL-17A level and detectable rate in the aqueous humor of patients with PDR are markedly lower than those in the vitreous fluid and aqueous IL-17A does not correlate with vitreous levels of other cytokines, and hence should not be used as a surrogate for IL-17A in the vitreous fluid.
Journal Article
Decreased extra-renal urate excretion is a common cause of hyperuricemia
2012
ABCG2, also known as BCRP, is a high-capacity urate exporter, the dysfunction of which raises gout/hyperuricemia risk. Generally, hyperuricemia has been classified into urate 'overproduction type' and/or 'underexcretion type' based solely on renal urate excretion, without considering an extra-renal pathway. Here we show that decreased extra-renal urate excretion caused by ABCG2 dysfunction is a common mechanism of hyperuricemia. Clinical parameters, including urinary urate excretion, are examined in 644 male outpatients with hyperuricemia. Paradoxically, ABCG2 export dysfunction significantly increases urinary urate excretion and risk ratio of urate overproduction.
Abcg2
-knockout mice show increased serum uric acid levels and renal urate excretion, and decreased intestinal urate excretion. Together with high ABCG2 expression in extra-renal tissues, our data suggest that the 'overproduction type' in the current concept of hyperuricemia be renamed 'renal overload type', which consists of two subtypes—'extra-renal urate underexcretion' and genuine 'urate overproduction'—providing a new concept valuable for the treatment of hyperuricemia and gout.
Hyperuricemia, or gout, is thought to arise either from urate overproduction or from decreased renal excretion of urate. Ichida
et al
. show that the extra-renal excretion of urate also has a role in the pathogenesis of hyperuricemia, and propose a new classification for patients with this disease.
Journal Article
Elevated Levels of Cytokines Associated with Th2 and Th17 Cells in Vitreous Fluid of Proliferative Diabetic Retinopathy Patients
2015
Macrophages are involved in low-grade inflammation in diabetes, and play pathogenic roles in proliferative diabetic retinopathy (PDR) by producing proinflammatory cytokines. T cells as well as other cells are also activated by proinflammatory cytokines, and infiltration into the vitreous of patients with PDR has been shown. In this study, we measured helper T (Th) cell-related cytokines in the vitreous of PDR patients to define the characteristics of Th-mediated immune responses associated with PDR. The study group consisted of 25 type 2 diabetic patients (25 eyes) with PDR. The control group consisted of 27 patients with epiretinal membrane (ERM), 26 patients with idiopathic macular hole (MH), and 26 patients with uveitis associated with sarcoidosis. Vitreous fluid was obtained at the beginning of vitrectomy, and centrifuging for cellular removals was not performed. Serum was also collected from PDR patients. IL-1β, IL-4, IL-6, IL-10, IL-17A, IL-17F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, IFN-γ, soluble sCD40L, and TNFα in the vitreous and serum samples were measured. Both percent detectable and levels of IL-4, IL-6, IL-17A, IL-21, IL-22, and TNFα in the vitreous were significantly higher than those in the serum in PDR patients. Vitreous levels of these cytokines and IL-31 were significantly higher in PDR than in ERM or MH patients. Vitreous levels of IL-4, IL-17A, IL-22, IL-31, and TNFα in PDR patients were also significantly higher than those of sarcoidosis patients. In PDR patients, vitreous IL-17A level correlated significantly with vitreous levels of IL-22 and IL-31, and especially with IL-4 and TNFα. Although it is unclear whether these cytokines play facilitative roles or inhibitory roles for the progression of PDR, the present study indicated that Th2- and Th17-related immune responses are involved in the pathogenesis of PDR.
Journal Article
Age-related differences in the clinical features of ocular sarcoidosis
2018
The distribution of age at diagnosis in ocular sarcoidosis has shifted towards the older age groups in developed countries. In systemic sarcoidosis, age-related differences in the clinical presentation, which reflect the therapeutic strategies, was reported. We retrospectively compared 100 consecutive patients from April 2010 to March 2016 who were initially diagnosed with ocular sarcoidosis by International Workshop on Ocular Sarcoidosis criteria. They were classified into elder (>65 years: 50 patients) and younger (≤65 years: 50 patients) groups by the age at diagnosis of uveitis associated with sarcoidosis. All patients received ophthalmic examination to assess the presence of seven intraocular signs and 4 laboratory parameters. Significantly fewer ocular signs (2.8 ± 1.5 and 3.6 ± 1.5; P = 0.0034) and abnormal laboratory results (1.5 ± 1.2 and 2.0 ± 1.2; P = 0.023) were detected in the elder group than in the younger group; statistical differences were found between the groups regarding the frequencies of mutton-fat keratic precipitates (40% and 64%; P = 0.012), vitreous opacities (60% and 78%; P = 0.0059), bilateral inflammation (64% and 80%; P = 0.012), and bilateral hilar lymphadenopathy between the groups (52% and 78%; P < 0.001). Multiple linear regression analysis showed negative correlations between age and number of detected ocular signs (r = -0.36, P < 0.001) and laboratory results (r = -0.20, P = 0.023). The characteristic ocular signs and abnormal laboratory results had a lower frequency in the elder patients compared with the younger patients. Probable or possible ocular sarcoidosis by the international criteria should increase with increased life expectancy in developed countries.
Journal Article
ABCG2 dysfunction causes hyperuricemia due to both renal urate underexcretion and renal urate overload
2014
Gout is a common disease which results from hyperuricemia. We have reported that the dysfunction of urate exporter ABCG2 is the major cause of renal overload (ROL) hyperuricemia, but its involvement in renal underexcretion (RUE) hyperuricemia, the most prevalent subtype, is not clearly explained so far. In this study, the association analysis with 644 hyperuricemia patients and 1,623 controls in male Japanese revealed that ABCG2 dysfunction significantly increased the risk of RUE hyperuricemia as well as overall and ROL hyperuricemia, according to the severity of impairment. ABCG2 dysfunction caused renal urate underexcretion and induced hyperuricemia even if the renal urate overload was not remarkable. These results show that ABCG2 plays physiologically important roles in both renal and extra-renal urate excretion mechanisms. Our findings indicate the importance of ABCG2 as a promising therapeutic and screening target of hyperuricemia and gout.
Journal Article
Common dysfunctional variants in ABCG2 are a major cause of early-onset gout
2013
Gout is a common disease which mostly occurs after middle age, but more people nowadays develop it before the age of thirty. We investigated whether common dysfunction of ABCG2, a high-capacity urate transporter which regulates serum uric acid levels, causes early-onset gout. 705 Japanese male gout cases with onset age data and 1,887 male controls were genotyped and the ABCG2 functions which are estimated by its genotype combination were determined. The onset age was 6.5 years earlier with severe ABCG2 dysfunction than with normal ABCG2 function (
P
= 6.14 × 10
−3
). Patients with mild to severe ABCG2 dysfunction accounted for 88.2% of early-onset cases (twenties or younger). Severe ABCG2 dysfunction particularly increased the risk of early-onset gout (odds ratio 22.2,
P
= 4.66 × 10
−6
). Our finding that common dysfunction of ABCG2 is a major cause of early-onset gout will serve to improve earlier prevention and therapy for high-risk individuals.
Journal Article
Common dysfunctional variants of ABCG2 have stronger impact on hyperuricemia progression than typical environmental risk factors
2014
Gout/hyperuricemia is a common multifactorial disease having typical environmental risks. Recently, common dysfunctional variants of
ABCG2
, a urate exporter gene also known as
BCRP
, are revealed to be a major cause of gout/hyperuricemia. Here, we compared the influence of ABCG2 dysfunction on serum uric acid (SUA) levels with other typical risk factors in a cohort of 5,005 Japanese participants. ABCG2 dysfunction was observed in 53.3% of the population investigated and its population-attributable risk percent (PAR%) for hyperuricemia was 29.2%, much higher than those of the other typical environmental risks, i.e. overweight/obesity (BMI ≥ 25.0; PAR% = 18.7%), heavy drinking (>196 g/week (male) or >98 g/week (female) of pure alcohol; PAR% = 15.4%) and aging (≥60 years old; PAR% = 5.74%). SUA significantly increased as the ABCG2 function decreased (P = 5.99 × 10
−19
). A regression analysis revealed that ABCG2 dysfunction had a stronger effect than other factors; a 25% decrease in ABCG2 function was equivalent to “an increase of BMI by 1.97-point” or “552.1 g/week alcohol intake as pure ethanol” in terms of ability to increase SUA. Therefore, ABCG2 dysfunction originating from common genetic variants has a much stronger impact on the progression of hyperuricemia than other familiar risks. Our study provides a better understanding of common genetic factors for common diseases.
Journal Article
The effects of URAT1/SLC22A12 nonfunctional variants,R90H and W258X, on serum uric acid levels and gout/hyperuricemia progression
2016
Urate transporter 1 (
URAT1/SLC22A12
), a urate transporter gene, is a causative gene for renal hypouricemia type 1. Among several reported nonsynonymous
URAT1
variants, R90H (rs121907896) and W258X (rs121907892) are frequent causative mutations for renal hypouricemia. However, no case-control study has evaluated the relationship between gout and these two variants. Additionally, the effect size of these two variants on serum uric acid (SUA) levels remains to be clarified. Here, 1,993 primary gout patients and 4,902 health examination participants (3,305 males and 1,597 females) were genotyped with R90H and W258X. These
URAT1
variants were not observed in any gout cases, while 174 subjects had the
URAT1
variant in 2,499 health examination participants, respectively (
P
= 8.3 × 10
−46
). Moreover, in 4,902 health examination participants, the
URAT1
nonfunctional variants significantly reduce the risk of hyperuricemia (
P
= 6.7 × 10
−19
; risk ratio = 0.036 in males). Males, having 1 or 2 nonfunctional variants of
URAT1
, show a marked decrease of 2.19 or 5.42 mg/dl SUA, respectively. Similarly, females, having 1 or 2 nonfunctional variants, also evidence a decrease of 1.08 or 3.89 mg/dl SUA, respectively. We show that
URAT1
nonfunctional variants are protective genetic factors for gout/hyperuricemia and also demonstrated the sex-dependent effect size of these
URAT1
variants on SUA (
P
for interaction = 1.5 × 10
−12
).
Journal Article
Bilateral idiopathic retinal vasculitis following coxsackievirus A4 infection: a case report
2017
Background
Coxsackieviruses are members of a group of viruses called the enteroviruses, which may cause respiratory and gastrointestinal symptoms, erythema, meningoencephalitis, myocarditis, pericarditis, and myositis. Unilateral acute idiopathic maculopathy caused by coxsackievirus A16 has been associated with hand, foot, and mouth disease, but only a few reports describe retinitis associated with coxsackievirus serotype B3 or B4. We report a case of bilateral multifocal obstructive retinal vasculitis that developed after coxsackievirus A4 infection.
Case presentation
A 60-year-old woman was referred to our department with bilateral visual disturbance that developed following flu-like symptoms. At the initial examination, best corrected visual acuity was 20/200 in the right eye and 20/50 in the left eye. The critical flicker frequency (CFF) was 23 Hz in the right eye and 27 Hz in the left eye. Fine white keratic precipitates with infiltrating cells were presented in the anterior chamber of both eyes, and multifocal retinal ischemic lesions were observed in the macula and posterior pole of both eyes. The retinal lesions corresponded with scotomas observed in Goldmann visual field test. On spectral domain-optical coherence tomography (SD-OCT), retinal lesions were depicted as hyper-reflective regions in the inner retina layers in both eyes, and disruption of ellipsoid line in the left eye., Fluorescein angiography exhibited findings indicative of multifocal obstructive retinal vasculitis. The patient had a history of current hypertension treated with oral therapy and glaucoma treated with latanoprost eye drops. Blood test for coxsackievirus antibody titers revealed that A4, A6, A9, B1, B2, B3, and B5 were positive (titers: 8–32). Abdominal skin biopsy of necrotic tissue suggested vascular damage caused by coxsackievirus. The general symptoms improved after 6 weeks, and the multifocal retinal ischemic lesions were partially resolved with residual slightly hard exudates. Only coxsackievirus A4 antibody titer increased from 4 to 32-fold after 14 months. However, hyper-reflective regions and disruption of the inner retinal layers on SD-OCT persisted especially in the right eye, and residual paracentral scotoma was observed in the right eye.
Conclusion
The present case suggests that coxsackievirus A4 causes bilateral multifocal obstructive retinal vasculitis with irreversible inner retinal damage.
Journal Article
Evaluation of mouse experimental autoimmune uveoretinitis by spectral domain optical coherence tomography
by
Harimoto, Kohzou
,
Karasawa, Yoko
,
Sakurai, Yutaka
in
Animals
,
Autoimmune Diseases - diagnosis
,
Disease Models, Animal
2014
Aims To evaluate the efficacy of spectral domain optical coherence tomography (SD-OCT) in monitoring the development of mouse experimental autoimmune uveoretinitis (EAU) as an animal model of endogenous uveitis, and to develop an OCT-based grading system for EAU severity. Methods C57BL/6 mice were immunised with human interphotoreceptor retinoid-binding protein (amino acid sequence 1–20) peptide and complete Freund's adjuvant to induce EAU. The development of EAU was monitored by SD-OCT serially throughout the disease course, and the images were graded from 1 to 4 and compared with the clinical and histopathological grades. Results SD-OCT images depicted retinal lamella structures including the inner segment/outer segment (IS/OS) line in normal mice. Retinal structural changes were observed on SD-OCT images in mice that developed EAU clinically scored as grade 1 or higher, which precisely corresponded to the pathological findings. The SD-OCT images of EAU were graded as follows: grade 1, a few infiltrating cells in the vitreous and retina; grade 2, increased vitreous cells, retinal vasculitis, and granulomatous lesion; grade 3, cell infiltration into the whole retina, disappearance of IS/OS line, and destruction of the retinal layer structure; and grade 4, disappearance of the outer retina. The SD-OCT grade of EAU based on these criteria correlated significantly with both the clinical grade (R2=0.282, p<0.005) and histopathological grade (R2=0.846, p<0.0001). Conclusions SD-OCT is useful for evaluating the development and severity of mouse EAU. The SD-OCT scoring system we developed accurately reflects clinical and histopathological changes.
Journal Article