Genome-wide screening reveals the genetic basis of mammalian embryonic eye development.

BACKGROUND: Microphthalmia, anophthalmia, and coloboma (MAC) spectrum disease encompasses a group of eye malformations which play a role in childhood visual impairment. Although the predominant cause of eye malformations is known to be heritable in nature, with 80% of cases displaying loss-of-function mutations in the ocular developmental genes OTX2 or SOX2, the genetic abnormalities underlying the remaining cases of MAC are incompletely understood. This study intended to identify the novel genes and pathways required for early eye development. Additionally, pathways involved in eye formation during embryogenesis are also incompletely understood. This study aims to identify the novel genes and pathways required for early eye development through systematic forward screening of the mammalian genome. RESULTS: Query of the International Mouse Phenotyping Consortium (IMPC) database (data release 17.0, August 01, 2022) identified 74 unique knockout lines (genes) with genetically associated eye defects in mouse embryos. The vast majority of eye abnormalities were small or absent eyes, findings most relevant to MAC spectrum disease in humans. A literature search showed that 27 of the 74 lines had previously published knockout mouse models, of which only 15 had ocular defects identified in the original publications. These 12 previously published gene knockouts with no reported ocular abnormalities and the 47 unpublished knockouts with ocular abnormalities identified by the IMPC represent 59 genes not previously associated with early eye development in mice. Of these 59, we identified 19 genes with a reported human eye phenotype. Overall, mining of the IMPC data yielded 40 previously unimplicated genes linked to mammalian eye development. Bioinformatic analysis showed that several of the IMPC genes colocalized to several protein anabolic and pluripotency pathways in early eye development. Of note, our analysis suggests that the serine-glycine pathway producing glycine, a mitochondrial one-carbon donator to folate one-carbon metabolism (FOCM), is essential for eye formation. CONCLUSIONS: Using genome-wide phenotype screening of single-gene knockout mouse lines, STRING analysis, and bioinformatic methods, this study identified genes heretofore unassociated with MAC phenotypes providing models to research novel molecular and cellular mechanisms involved in eye development. These findings have the potential to hasten the diagnosis and treatment of this congenital blinding disease.

Transplant outcomes in kidney recipients with lupus nephritis, and systematic review.

BACKGROUND: Despite improved survival of patients with lupus nephritis (LN), some require kidney transplantation because of progression to end-stage renal disease (ESRD). However, the transplant outcomes of these patients and other recipients have not been thoroughly compared. METHODS: In total, 1848 Korean kidney recipients who underwent transplantation from 1998 to 2017 at two tertiary referral centers were evaluated retrospectively. Among them, 28 recipients with LN, and 50 control recipients matched by age, sex, and donor type, were compared with respect to graft and patient survival. We pooled our data with 17 previous cohort studies in which the graft survival of recipients with LN was described in detail. RESULTS: During the median follow-up period of 9.5 years (maximum 21 years), graft failure (GF) occurred in 10.7% and 16.0% of LN and control recipients, respectively. No differences were found in the rates of GF and death-censored graft failure or patient survival between the two groups. The risks of acute T cell-mediated and antibody-mediated rejection were also similar between the two groups. The pooled analysis showed similar 1- and 5-year graft survival rates between LN and control recipients. CONCLUSIONS: Kidney transplantation is an acceptable option in patients with concurrent LN and ESRD.

Low Hemoglobin A1c Increases the Risk of Disability in Community-dwelling Older Non-diabetics Adults.

OBJECTIVE: To describe the health characteristics of individuals with low HbA1c levels and evaluate the association between HbA1c level and disability or all-cause mortality in non-diabetic older adults. DESIGN: Prospective observational cohort study. SETTING: Seongnam, Gyeongi Province, Korea. PARTICIPANTS: Among the 1,000 community-dwelling Koreans ≥ 65 years of age who were followed for 5 years, 760 non-diabetic individuals were analyzed. MEASUREMENTS: Activities of Daily Living (ADL) and Instrumental ADL (IADL) were evaluated and mortality data were obtained from the National Statistics Office of Korea. RESULTS: The mean age was 76.3 (SD 9.0) years, and 319 subjects (42.0%) were male. Lower level of HbA1c was associated with less frequent hypertension and less frequent use of aspirin or statin, and lower values of body mass index, hematocrit, total iron-binding capacity, albumin, and cholesterol level. The participants were categorized into 3 groups according to their HbA1c (group I, < 5.5%; group II, 5.5~5.9%; and group III, 6.0 ~ 6.4%). Although, there was no significant difference in functional status according to baseline HbA1c level, disability was more frequently observed as the HbA1c level decrease (18.3% in group I, 12.5% in group II, and 5.3% in group III, p=0.029) at the 5-year follow-up evaluation. There were 172 deaths (22.6%) during the follow-up period. There was no significant difference in mortality among the groups, however, group I had a 2.071-fold higher risk for the incident disability or mortality over group III after adjusting age, gender, and possible confounder (95% CI: 1.040 ~ 4.124, p=0.038). CONCLUSIONS: Lower level of HbA1c was associated with an increased risk of disability in non-diabetic older adults.

Remission of proteinuria indicates good prognosis in patients with diffuse proliferative lupus nephritis.

Proteinuria is a well-known risk factor for the progression of renal dysfunction in chronic kidney disease; however, its importance for estimating the prognosis of lupus nephritis requires verification. Korean adult patients with renal biopsy-diagnosed diffuse proliferative lupus nephritis who had undergone three or more consecutive urine protein to creatinine ratio or urine dipstick tests within six months after renal biopsy were enrolled. The cumulative risks, predictors, and outcomes of proteinuric remission and flare were evaluated. This study included 26 men and 167 women with a mean age at renal biopsy of 31.2 ± 9.8 years. Eighty-two (42.5%) patients experienced proteinuric remission during the follow-up period. During a mean follow-up of 157.9 ± 69.5 months, among patients who achieved proteinuric remission, one died, one developed end-stage renal disease (ESRD), and two had composite outcomes; among patients without remission, nine died, 24 developed ESRD, and 30 had composite outcomes. Patients who achieved proteinuric remission had a 0.089-fold risk (95% CI: 0.011-0.736) of mortality, 0.110-fold risk (95% CI: 0.013-0.904) of incident ESRD, and 0.210-fold risk (95% CI: 0.048-0.920) of a composite outcome compared to patients without remission. Among the 82 patients who achieved proteinuric remission, 59 (72.0%) experienced at least one proteinuria flare; however, relapse did not correlate with the incidence of outcomes. In conclusion, proteinuric remission is an independent predictive prognostic marker of good renal survival and mortality, regardless of the interval from biopsy to remission, recurrence of proteinuria after remission, renal function status at remission, or hematuria remission.

Determining the Cut-off Values for Sarcopenia in the Korean Elderly Population Using Bioimpedance Analysis.

BACKGROUND: Bioimpedance analysis (BIA) is known to be a useful method for assessing sarcopenia because cost-effective and not involving radiation exposure. However, the cut-off values for sarcopenia using BIA have not yet been determined in the Korean population. OBJECTIVES: To establish the cut-off values for sarcopenia in the Korean elderly population with the use of BIA. METHODS: Body composition assessed by BIA was obtained in 7,641 participants aged 20-34 years and 3,902 participants aged ≥65 years from data routinely collected during health examinations at Seoul National University Gangnam Center. Appendicular skeletal muscle mass was adjusted for height and weight. Gender-specific cut-points for class I and class II sarcopenia were defined as 1 and 2 standard deviations below the mean in the reference group aged 20-34 years, respectively. In addition, the gender-specific, lowest 20th percentile cut-offs for muscle mass in participants aged ≥65 years were determined. RESULTS: The cut-offs for class I and class II sarcopenia in men for height-adjusted appendicular skeletal mass were 6.74 kg/m2 and 5.96 kg/m2 and for weight-adjusted appendicular skeletal mass were 29.4% and 27.4%, respectively; those in women for height-adjusted appendicular skeletal mass were 4.93 kg/m2 and 4.35 kg/m2, and for weight-adjusted appendicular skeletal mass were 25.6% and 23.9%, respectively. The lowest 20th percentile cut-offs for height-adjusted and weight-adjusted appendicular skeletal mass were 6.69 kg/m2 and 28.9% in men, and 5.76 kg/m2 and 24.5% in women, respectively. Based on the derived cut-offs, prevalence of class II sarcopenia in participants ≥65 years of age for height-adjusted and weight-adjusted appendicular skeletal mass was 3.7% and 3.5% in men, and 0.2% and 11.2% in women, respectively. Among the above-mentioned definitions, sarcopenia by height-adjusted appendicular skeletal mass was significantly associated with 2-year mortality in older participants. CONCLUSIONS: Muscle mass deficit in the Korean population can be assessed based on the cut-offs determined in this study using BIA.

The effects of cyclophosphamide and mycophenolate on end-stage renal disease and death of lupus nephritis.

Debate continues about the optimal treatment modality of lupus nephritis (LN). We compared the efficacy and safety of intravenous cyclophosphamide (CYC) and mycophenolate mofetil (MMF) for LN treatment in Korea. After searching for systemic lupus erythematosus (SLE) patients diagnosed between 1998 and 2007 with the diagnostic code of ICD10, we selected the 71 patients who were treated with CYC or MMF without any other immunosuppressant except systemic steroid. Composite outcome was defined as progression to end-stage renal disease (ESRD) and/or all-cause mortality. The initial manifestations of the CYC group were more severe than those of the MMF group. The mean daily MMF dose was 980 ± 100 mg for 21.67 ± 18.25 months. The mean monthly dose per CYC pulse therapy was 850 ± 30 mg for 17.04 ± 13.15 months. The incidence of composite outcome was 5/20 (25%) in the MMF group and 4/51 (7.8%) in the CYC group. The relative risk (RR) for composite outcome in the CYC group was 0.249 (95% CI for RR: 0.067-0.934, p = 0.039) compared with the MMF group with Cox's hazard proportional analysis. In Kaplan-Meier analysis, the probability of composite outcome was lower in the CYC group than in the MMF group (Log rank test p-value = 0.026). The results of this retrospective study suggest that intravenous CYC therapy may be more efficacious in averting ESRD and death than MMF. These results need to be confirmed in a larger randomized controlled trial.

Tacrolimus is an alternative therapeutic option for the treatment of refractory lupus nephritis.

We conducted an open-labeled, prospective study to determine the efficacy and safety of tacrolimus as an alternative therapeutic option for those patients with refractory lupus nephritis. The study population comprised one male and eight female patients with diffuse proliferative lupus nephritis. All patients had failed to respond to sufficient intravenous cyclophosphamide therapy with proteinuria of >or=1 g/day and active urinary sediments. Tacrolimus (0.1 mg/kg/day) was administered for 1 year with adjusting drug level (4-10 microg/l). The mean serum creatinine level and spot urine protein creatinine ratio (UPCR) at baseline were 1.39 mg/dl and 2.27, respectively. After the treatment, proteinuria reduced significantly from median UPCR value of 2.19 (range, 1.19-3.34) to 0.44 (range, 0.12-2.13) (p < 0.05). Seven (78%) of the nine patients showed a complete clinical response, which was defined as stabilization in the disease-activity markers and serum creatinine level with reduction of >or=50% in UPCR; two patients showed complete remission with UPCR <0.2. One patient showed treatment failure because of the disease progression. No serious adverse effects were observed during the study. This study demonstrates that tacrolimus can show a significant therapeutic response in cases that are refractory to the standard regimen for diffuse proliferative lupus nephritis.

Depression and health-related quality of life in maintenance hemodialysis patients.

BACKGROUND: This study was designed to determine the prevalence of depression among hemodialysis (HD) patients from urban hospitals in Korea, to illustrate demographic factors and biomarkers associated with depression and health-related quality of life (HRQOL), and to demonstrate association between depression and HRQOL. PATIENTS AND METHODS: For this multicenter, cross-sectional study, 160 HD patients from 3 university teaching hospitals and 3 local dialysis units in Korea were enrolled. Korean Beck's depression inventory and Korean version of Kidney Disease Quality of Life short form, version 1.3 (KDQOL-SFTM 1.3) were used to evaluate depression and quality of life, respectively. RESULTS: Depression was found in 51 out of 160 (31.9%) patients. Old age (> 60 years old), low hemoglobin level (< 10 g/dl), and low economic status were associated with depression, and old age (OR 6.138, p = 0.001) was the most important risk factor among them. Old age, female gender, presence of diabetes mellitus, high comorbidity index score (modified Charlson comorbidity index > or = 6), hypoalbuminemia (< 4.0 g/dl), and high CRP (> 0.5 mg/dl) were common factors associated with decreased HRQOL. Depression and HRQOL showed inverse linear relationship. CONCLUSIONS: Moderate to severe depression was common in maintenance HD patients in Korea. Among factors associated with depression and decreased HRQOL, some characteristics are potentially modifiable by social and medical intervention. Further prospective studies are warranted to see whether depression and HRQOL can be improved by modifying these factors.

Effective removal of leptin via hemodiafiltration with on-line endogenous reinfusion therapy.

AIMS: Leptin is a middle-molecular weight uremic toxin. Hemodiafiltration with on-line endogenous reinfusion (HFR) is a novel dialytic method combining the processes of diffusion, convection and adsorption. We performed a prospective crossover study of patients with end-stage renal disease to investigate the effect of HFR therapy on the level of leptin as compared to conventional low flux hemodialysis (LHD). METHODS: Eleven stable hemodialysis patients were treated with LHD for 12 weeks and then treated with HFR (SG30 Plus; Sorin Group Italia S.r.1, Mirandola, Italy) for 12 weeks. RESULTS: After 12 weeks of HFR treatment, serum leptin levels significantly decreased (17.1 (2.66 - 39.5) at Week 12 vs. 12.3 (1.80 - 24.3) ng/ml at Week 24, p = 0.014). Although serum adiponectin levels also decreased (1.66 (1.44 - 1.86) at Week 12 vs. 1.12 (0.79 - 1.34) g/ml at Week 24, p = 0.001), the ratio of leptin to adiponectin did not increase after HFR treatment. Serum beta2-microglobulin (beta2M) levels significantly decreased (37.7 (29.8 - 42.6) at Week 12 vs. 28.3 (26.5 - 32.2) mg/dl at Week 24, p = 0.002). Dry weight, Kt/V(urea), normalized protein equivalent of nitrogen appearance, subjective global assessment, and serum albumin levels of the patients were not changed after HFR treatment. There was no difference in the serum levels of C-reactive protein or interleukin-6 between Week 12 and Week 24. CONCLUSIONS: The results of our study indicate that HFR may be a better therapy than LHD for removal of middle-molecular-weight uremic toxins such as leptin and b2M.

The clinical significances of simple renal cyst: Is it related to hypertension or renal dysfunction?

Simple renal cyst has controversy related to hypertension and renal dysfunction. We analyzed the impacts of cyst on hypertension and renal dysfunction, focusing on elimination of the confounding factors. We grouped 436 patients and 436 controls by characteristics of cyst and stratified with clinical parameters among 6603 patients who had routine health check-up in Seoul National University Bundang Hospital, Seongnam, Korea. The presence of cyst was related to hypertension but not to renal dysfunction. The number and the size of cyst were independent risk factors to the prevalence of hypertension. The presence of multiple renal cysts was related to hypertension in males, in persons over the age of 60 years, in persons with glomerular filtration rate (GFR) more than 60 ml/min/1.73 m2, or in persons without proteinuria. The effect of the large cyst and the peripheral cyst on the prevalence of hypertension was similar to that of the multiple cyst. The blood pressure of the multiple-cyst group, the large-cyst group, or the peripheral-cyst group was higher than that of the single-cyst group, the small-cyst group, or the perihilar-cyst group, respectively, regardless of antihypertensive medications. In conclusion, the presence of cysts or characteristics of cyst were not related to the decreased GFR. In conclusion, the presence of simple renal cyst was related to hypertension but not to renal dysfunction. The effect of simple cyst on hypertension was evident in males, aged persons, and persons without the evidence of renal disease. The number, size, and location were important characteristics of cyst related to hypertension.

Utero-tubal transfer of mouse embryos.

A successful embryo transfer depends on the quality of the transferred embryos, recipients, and the transfer techniques. Among these, transfer techniques are often the limiting factor because transfer methodologies and personal skills vary. Suboptimal embryo transfer procedures can compromise transgenic experiments (pronuclear microinjection and gene targeting) and critical steps of mouse colony maintenance (embryo cryopreservation and mouse line rederivation). Here we present an efficient and simple procedure utilizing specific designs to improve the transfer quality. A 100% implantation rate is observed after the utero-tubal embryo transfer, which indicates that the modified method successfully prevents the embryos from flowing out of the punctured hole during embryo transfer. We believe this alternative methodology is able to fulfill the need of high efficiency of animal production.

Clinical implications of antineutrophil cytoplasmic antibody test in lupus nephritis.

To elucidate the prevalence and clinical implications of antineutrophil cytoplasmic antibody (ANCA) in lupus nephritis (LN), we examined ANCA by indirect immunofluorescence and by ELISA against antilactoferrin (anti-LF) and antimyeloperoxidase (anti-MPO) antibody. To discriminate perinuclear ANCA (pANCA) with antinuclear antibody (ANA), all the ANCA-positive sera were tested again after incubating patients' sera with single-stranded (SS) and double-stranded (ds) DNA. These results were compared with clinicopathologic manifestations and clinical courses of LN. ANCA was positive in 19 (37.3%) of 51 LN patients. Among these LN patients, 3 had cytoplasmic ANCA (cANCA) and 16 had pANCA. ANCA was not found in 8 SLE patients without nephritis and 30 normal controls. The presence of ANCA, particularly pANCA, was associated with the presence of nephritis (18/51 cases vs. 0/8 cases, p < 0.05), especially with diffuse proliferative lupus nephritis, WHO class IV (17/18 cases vs. 21/31 cases, p < 0.05) as well as the presence of anti-dsDNA antibody (17/19 cases vs. 18/30 cases, p < 0.05). Patients with ANCA frequently had deterioration of renal function (3/16 vs. 0/26 cases). Anti-LF antibody was positive in 13 patients. Among those, 12 patients had nephritis. Five patients with anti-LF antibody did not have ANCA, but 7 had pANCA, and 1 had cANCA. Patients with anti-LF antibody had lower initial creatinine levels than those without it [serum creatinine (mg/dl): 0.78 (0.6-1.0) vs. 1.43 (0.5-5.0), p < 0.05]. Anti-MPO antibody was positive in only 1 patient, suggesting that MPO is a rare antigen for ANCA in LN.

Prognostic factors of diffuse proliferative lupus nephritis.

BACKGROUND: Diffuse proliferative lupus nephritis (DPLN) is the most severe form in lupus nephritis. PATIENTS AND METHODS: We retrospectively analyzed 90 DPLN patients who were confirmed by kidney biopsy and treated at least for 12 months to compare the effectiveness of treatment modalities and to investigate the prognostic factors of DPLN. The patients were categorized to intravenous cyclophosphamide pulse (CY) group and oral corticosteroid (with/without cytotoxic drug, PO) group. RESULTS: When the CY group (69 patients) and PO group (21 patients) were compared, there were no differences between two groups in sex, age, histologic chronicity index (CI, 4.55 vs 3.76; CY vs PO, respectively), mortality rate (4.3% vs 0%), remission rate of nephritis (at 3-year 59. 1 % vs 75.5%), renal survival rate (at 5-year 88.0% vs 91.7%) and complications of treatment, but significant differences in the frequency of nephrotic syndrome (66.7% vs 33.3%) and initial azotemia (30.4% vs 0%). histologic activity index (7.14 vs 4.33) and relapse rate (2.9% vs 42.9%). When the remission group (49 patients) and non-remission group (41 patients) were compared, CI, initial renal insufficiency, male sex and the duration of nephritis were the prognostic factors for remission in univariate analysis, and male sex (OR 10.99) and CI (OR 9.89) in multivariate analysis. When the remission group (35 patients) and non-remission (34 patients) group were compared in the CY group, CI was the prognostic factor in univariate analysis, and CI (OR 8.63) and male sex (OR 5.54) in multivariate analysis. The initial renal insufficiency (OR 12.74) and male sex (OR 7.99) were the prognostic factors for renal survival. The renal survival rate was 100% in remission-induced patients. CONCLUSION: We conclude that CI, male sex, initial renal insufficiency were the prognostic factors of DPLN, and treatment with oral corticosteroid could induce remission in patients who had mild histologic and clinical features. Therefore it would be necessary to evaluate the prognostic factors before the selection of treatment modality.

Temporal changes and reversibility of carbamylated hemoglobin in renal failure.

The detection of carbamylated hemoglobin (CarHb) is known to be useful in determination of the chronicity of uremia. However, the time course of the in vivo reaction between isocyanic acid and terminal valine residues of the hemoglobin chain is not clearly defined. To assess the temporal relationship and reversibility of carbamylation, we prospectively measured CarHb as micrograms of valine hydantoin per gram of hemoglobin (microg VH/g Hb) by high-performance liquid chromatography in 37 patients with acute renal failure (ARF), 53 patients with chronic renal failure (CRF), and six patients with successful kidney transplant. Patients with ARF had a lower median CarHb concentration (53.2 microg VH/g Hb; range, 24.6 to 97.1 microg VH/g Hb) than those with CRF (115.0 microg VH/g Hb; range, 34.6 to 286.5 microg VH/g Hb; P < 0.01), but had a higher value (53.2 microg VH/g Hb; range, 24.6 to 97.1 microg VH/g Hb) than 31 normal controls (36.6 microg VH/g Hb; range, 19.9 to 62.9 microg VH/g Hb; P < 0.05). In patients with ARF, the CarHb concentration positively correlated with the number of days of illness (r = 0.74; P < 0.01). The patients with ARF of 10 or more days' duration had a higher CarHb concentration (68.7 microg VH/g Hb; range, 36.0 to 93.9 microg VH/g Hb) than those with a shorter duration of ARF (33.7 microg VH/g Hb; range, 24.6 to 55.8 microg VH/g Hb; P < 0.01) despite similar blood urea nitrogen and serum creatinine values. However, they had a lower concentration of CarHb (68.7 microg VH/g Hb; range, 36.0 to 93.9 microg VH/g Hb) than CRF patients with comparable serum creatinine values (112.5 microg VH/g Hb; range, 34.6 to 286.5 microg VH/g Hb; P < 0.01). In patients with a kidney transplant, CarHb concentration declined by 19.7% (range, 12.3% to 35.6%) within 2 to 3 weeks after receiving the graft, while the level of hemoglobin increased by 25% (range, 4.0% to 46.6%) during the same period. Therefore, the total blood CarHb (CarHb x hemoglobin concentration) was not significantly changed. We concluded that the in vivo reaction of carbamylation of hemoglobin progressed during the period of uremia, and there might exist some irreversible preformed CarHb in advanced stages of CRF.

Idiopathic retroperitoneal fibrosis presented as an abdominal mass and nephrotic syndrome.

We present a 30-year-old male patient who was initially diagnosed as minimal change nephrotic syndrome, 5 years later, the patient developed a localized form of idiopathic retroperitoneal fibrosis (IRF). An elevated ESR and concomitant nephrotic syndrome in the patient suggested the immunologic nature of IRF, IRF has been reported in association with collagen diseases and rarely with proliferative and nonproliferative glomerulopathies. To our knowledge, the association between minimal change lesion (MC) and IRF has not been reported. Furthermore, the fact that IRF presented itself as an abdominal mass and lacked systemic symptoms was also unusual.