Prevalence of arterial stiffness and associated factors in Thai hemodialysis patients: A multicenter cross-sectional study.

BACKGROUND: Hemodialysis (HD) patients have higher risks of cardiovascular morbidity and mortality compared to the general population. Cardio-femoral pulse wave velocity (cfPWV) is associated with cardiovascular morbidity and mortality in HD patients. This study aimed to evaluate the prevalence and associated factors of arterial stiffness in Thai HD patients. MATERIALS AND METHODS: This cross-sectional multicenter study was conducted at 4 HD centers in Bangkok, Thailand. cfPWV and peripheral blood pressure were assessed using SphygmoCor XCEL Model EM4C (AtCor medical Inc., Sydney, Australia). Significant arterial stiffness was defined by cfPWV > 10 m/s. Univariate and multivariable regression models were used to identify factors associated with arterial stiffness. RESULTS: 144 HD patients were assessed for arterial stiffness by cfPWV measurement. The mean age of the patients was 57.8 ± 12.8 years, with 50% male and a mean dialysis vintage of 7.6 years. The mean cfPWV was 11.7 ± 3.0 m/s. The prevalence of increased arterial stiffness was 73.6%. Multivariable analysis showed that older age, hypertension, lower HD adequacy, and higher fasting plasma glucose were independently associated with arterial stiffness. CONCLUSION: There was a high prevalence of arterial stiffness among HD patients. Some modifiable factors found to be independently associated, including dialysis adequacy and glycemic control, should be further investigated to identify approaches to retard vascular stiffness.

Updated management for antibody-mediated rejection: opportunity to prolong kidney allograft survival.

PURPOSE OF REVIEW: Antibody-mediated rejection (ABMR) is an important barrier to achieve long-term kidney allograft survival. Human leukocyte antibody (HLA)-incompatibility and ABO-incompatibility are the two main mechanisms of ABMR. Nevertheless, the advances in managing ABMR have changed the paradigm for kidney transplantation. This review aimed to emphasize the HLA-incompatibility and ABO-incompatibility kidney transplant and update the management of ABMR. RECENT FINDINGS: HLA-incompatibility kidney transplantation is a strong risk factor for ABMR. Donor-specific antibody (DSA) is a surrogate biomarker that prevents long-term allograft survival. The standard treatment for ABMR has unfavorable results. New drugs that target the B cell are a promising approach to treat ABMR. In the past, ABO-incompatibility kidney donor was an absolute contraindication but now, it is widely accepted as an alternative organ resource. The advancement of ABO antibody removal and B-cell depletion therapy has been successfully developed. ABO isoagglutination remains the main biomarker for monitoring ABMR during the transplantation process. C4d staining without inflammation of the kidney allograft is the marker for the accommodation process. SUMMARY: With the shortage of organ donors, transplant experts have expanded the organ resources and learned how to overcome the immunological barriers by using novel biomarkers and developing new treatments that support long-term graft survival.

Long-term kidney outcomes after leptospirosis: a prospective multicentre cohort study in Thailand.

BACKGROUND: Leptospirosis is one of the most important public-health zoonotic diseases in the tropics that can cause severe organ dysfunction and death. Currently there are insufficient data on long-term renal dysfunction in patients after leptospirosis infection. METHODS: A prospective multicentre cohort study was conducted at 15 hospitals in the Sisaket province of Thailand. Confirmed leptospirosis patients admitted from 1 December 2015 to 30 November 2018 were followed between 1 February 2020 and 31 October 2020 (median 4.1 years after hospital discharge). The primary outcome was a composite of major kidney adverse events (MAKEs) including all-cause mortality, dialysis and new-onset chronic kidney disease (CKD). RESULTS: Of the 217 confirmed leptospirosis cases enrolled, 32.7% were classified as having severe leptospirosis. Fifteen cases (6.9%) were deceased at the time of hospital admission. After a median follow-up time of 4.18 years, 30 patients had died and 33 patients developed CKD. Patients with severe leptospirosis had a significantly higher risk of MAKEs {adjusted hazard ratio 2.45 [95% confidence interval (CI) 1.44-4.18]}. Patients with intensive care unit admission, pulmonary haemorrhage and acute kidney injury also had a higher risk of MAKEs and all-cause mortality. Participants with severe leptospirosis in the follow-up cohort showed a higher risk of developing CKD compared with non-severe leptospirosis [adjusted odds ratio 3.22 (95% CI 1.04-9.96)], especially renal magnesium and phosphate wasting. CONCLUSION: Leptospirosis patients, especially severe leptospirosis, are associated with long-term kidney sequelae. Our finding reflects the importance of long-term follow-up and the urgent need for specific interventions.

The Role of Erythropoietin Levels in Predicting Long-Term Outcomes following Severe Acute Kidney Injury.

INTRODUCTION: Acute kidney injury (AKI) survivors are at an increased risk of chronic kidney disease, end-stage kidney disease, and mortality. Little is known about the effect of erythropoietin (EPO), a kidney-producing hormone, in post-AKI setting. We aimed to investigate the role of EPO as a predictor of long-term outcomes in post-severe AKI survivors. METHODS: We performed a retrospective analysis of post-AKI cohort conducted between August 2018 and December 2021. Adults who survived severe AKI stages 2-3 were enrolled. Serum EPO was obtained at 1 month after hospital discharge. We explored whether EPO level could predict long-term kidney outcomes at 12 months including mortality, kidney replacement therapy, doubling serum creatinine, and major adverse kidney events at 365 days. RESULTS: One hundred and twelve patients were enrolled. Median EPO level was significantly higher in non-survivors than survivors (28.9 [interquartile range: 16.2-50.7] versus 11.6 mU/mL [7.5-22.3], p = 0.003). The best EPO level cut-off was 16.2 mU/mL (sensitivity 77.8%, specificity 62.1%). Serum EPO predicted 12-month mortality with an area under the curve (AUC) of 0.69. Combining clinical model using age, baseline, and discharge kidney function with serum EPO improved prediction with AUC of 0.74. Multivariable analysis demonstrated that high-level of EPO group had significantly higher mortality compared with low-level EPO group (15.2% vs. 3.0%, p = 0.020). Hematocrit was significantly lower in high-level EPO group compared with low-level EPO group at 12 months (33.4 ± 1.1% vs. 36.0 ± 0.9%, p = 0.038). CONCLUSIONS: Plasma EPO appears to be a useful marker for predicting long-term outcome in post-severe AKI survivors.

Metabolic effects of kidney donation: A Bayesian analysis of matched cohorts.

The kidney is a notable site of glycolysis, gluconeogenesis, and fatty acid oxidation. Loss of a kidney after kidney donation might, therefore, affect the glucose and lipid metabolism of the donors. This matched cohort study investigated the effect of nephrectomy on glucose and lipid metabolisms using Bayesian hypothesis testing. There were 77 pairs of matched donor-control pairs in the present study. Clinical and laboratory data of the participants, at baseline and 1-year, were extracted from electronic medical records. Comparisons between donor and control groups were performed using the Bayesian independent samples t-test or Bayesian Mann-Whitney test. The Bayes Factor for alternative hypothesis over null hypothesis (BF10 ) was used to compare the two competing hypotheses. The BF10 of 3 or more was considered evidence for the alternative hypothesis. Comparing changes from baseline to 1-year between donors and controls, the BF10 of triglycerides, high-density lipoprotein cholesterol (HDL-C), triglyceride-glucose (TyG) index of insulin resistance, and estimated glomerular filtration rate (eGFR) were 7.95, 3.96, 30.13, and 1.32 x 1041 , respectively signifying that the change of these variables in the donors differed from those in the controls (alternative hypothesis). Triglyceride, HDL-C, and TyG index of the donors increased more than those of the controls while eGFR of the donor decreased more than that of the controls. Our data suggest that triglycerides and insulin resistance increase after donor nephrectomy. Kidney donors should be informed about these metabolic changes and should adhere to lifestyle recommendations that may mitigate insulin resistance.

Effects of phosphate binders on bone biomarkers and bone density in haemodialysis patients.

AIM: The incidences of osteoporosis, fracture and vascular calcification increase concordantly with the progression of chronic kidney disease (CKD). CKD-mineral bone disease (CKD-MBD) induced by hyperphosphatemia is a major pathophysiologic mechanism. The effects of phosphate binders on bone turnover biomarkers and bone mineral density (BMD) in haemodialysis patients are still inconclusive. Our aim is to demonstrate the effects of these phosphate binders on different aspects of CKD-MBD. METHODS: We conducted a prospective cohort of 65 haemodialysis patients to investigate the effect of 12-month monotherapy of phosphate binders composing calcium-based phosphate binders (CPB) or non-calcium-based phosphate binders (NCPB), including sevelamer and lanthanum, on bone turnover biomarkers and BMD changes. The performance of bone turnover biomarkers to predict low BMD was attentively determined. RESULTS: When compared with CPB, NCPB use was associated with higher levels of bone turnover biomarkers. NCPB was also associated with lower BMD at lumbar and distal radius. Total procollagen type 1N-terminal propeptide (P1NP), bone-specific alkaline phosphatase (BALP), and tartrate-resistant acid phosphatase 5b (TRAP5b) provided the best performance for diagnosing low BMD in haemodialysis patients. CONCLUSION: Switching from CPB to NCPB might increase bone biomarkers and prevent the development of adynamic bone disease. On the contrary, NCPB should be cautiously used in haemodialysis patients who already had low BMD. P1NP, BALP and TRAP5b could be used to guide the appropriate management, including anti-resorptive and anabolic medications, and predict low BMD in haemodialysis patients treated with phosphate binders.

A case of successful treatment of severe COVID-19 pneumonia with favipiravir and tocilizumab in post-kidney transplant recipient.

We report a case of COVID-19 in kidney transplant patient in Thailand. A 58-year-old 2 years post-kidney transplant recipient, with maintenance immunosuppression of tacrolimus, mycophenolate mofetil (MMF), and prednisolone, presented with acute diarrhea which followed by fever on day 12. Symptoms of pneumonia together with lymphopenia from complete blood count were developed on day 7 after onset of fever with the x-ray finding of bilateral multifocal patchy infiltration. COVID-19 infection has been confirmed by reverse real-time polymerase chain reaction (PCR) in nasal swab as well as found in stool. Darunavir together with ritonavir, hydroxychloroquine, azithromycin, and favipiravir was initiated on the first day of admission at primary hospital. Patient has been transferred to our hospital on day 2 of admission in which tacrolimus together with MMF was discontinued. High-flow nasal cannula oxygen therapy was required on days 4-5 of hospitalization. Tocilizumab was administered after rising of serum IL-6 level. Symptoms of pneumonia were improved in which no oxygen treatment required from day 10 of hospitalization. Drug interaction between tacrolimus and anti-viral treatment leads to severely high level of tacrolimus which caused reversible acute kidney injury (AKI) after supportive treatment.

Comprehensive versus standard care in post-severe acute kidney injury survivors, a randomized controlled trial.

BACKGROUND: Currently, there is a lack of evidence to guide optimal care for acute kidney injury (AKI) survivors. Therefore, post-discharge care by a multidisciplinary care team (MDCT) may improve these outcomes. This study aimed to demonstrate the outcomes of implementing comprehensive care by a MDCT in severe AKI survivors. METHODS: This study was a randomized controlled trial conducted between August 2018 to January 2021. Patients who survived severe AKI stage 2-3 were enrolled and randomized to be followed up with either comprehensive or standard care for 12 months. The comprehensive post-AKI care involved an MDCT (nephrologists, nurses, nutritionists, and pharmacists). The primary outcome was the feasibility outcomes; comprising of the rates of loss to follow up, 3-d dietary record, drug reconciliation, and drug alert rates at 12 months. Secondary outcomes included major adverse kidney events, estimated glomerular filtration rate (eGFR), and the amount of albuminuria at 12 months. RESULTS: Ninety-eight AKI stage 3 survivors were enrolled and randomized into comprehensive care and standard care groups (49 patients in each group). Compared to the standard care group, the comprehensive care group had significantly better feasibility outcomes; 3-d dietary record, drug reconciliation, and drug alerts (p < 0.001). The mean eGFR at 12 months were comparable between the two groups (66.74 vs. 61.12 mL/min/1.73 m2, p = 0.54). The urine albumin: creatinine ratio (UACR) was significantly lower in the comprehensive care group (36.83 vs. 177.70 mg/g, p = 0.036), while the blood pressure control was also better in the comprehensive care group (87.9% vs. 57.5%, p = 0.006). There were no differences in the other renal outcomes between the two groups. CONCLUSIONS: Comprehensive care by an MDCT is feasible and could be implemented for severe AKI survivors. MDCT involvement also yields better reduction of the UACR and better blood pressure control. Trial registration Clinicaltrial.gov: NCT04012008 (First registered July 9, 2019).

Tenofovir alafenamide nephrotoxicity: a case report and literature review.

BACKGROUND: Tenofovir alafenamide (TAF), a novel prodrug of tenofovir (TFV), has become the preferred drug for the treatment of HIV-1 and chronic hepatitis B infection in clinical practice. Results from clinical trials showed that it had better renal and bone mineral outcomes compared to tenofovir disoproxil fumarate (TDF). However, as we have seen with TDF, side effects from the new medication can be more prevalent and recognized after extensive use in real world situations. Sporadic cases of acute kidney injury in patients using TAF have started to emerge. CASE PRESENTATION: We report a case of 49-year-old Thai, HIV treatment-experienced female with hypertension presented with worsening renal function after switching her antiretroviral regimen from TDF, emtricitabine (FTC), and lopinavir/ritonavir (LPV/r) to TAF, FTC and dolutegravir (DTG) for 3 months. Kidney biopsy showed distinctive picture of tenofovir nephrotoxicity with acute tubular injury and mitochondrial injury. The possible causes of acute kidney injury and nephrotoxicity from TAF for this patient were discussed. We have extensively reviewed all published case reports of TAF-associated nephrotoxicity and summarized the essential information in this article. CONCLUSION: Although TAF has less nephrotoxicity compared with TDF; renal function should always be monitored after the initiation of both drugs. Future large cohort studies are required to identify the risk factors of TAF-associated nephrotoxicity and to design an effective preventive strategy.

Maximizing anti-HBs seroresponsiveness in kidney transplant waitlist patients: A tertiary-center perspective
.

BACKGROUND: Patients on dialysis are at risk of hepatitis B virus (HBV) infection, and antibodies against the hepatitis B surface antigen (anti-HBs) ≥ 10 IU/L are required. However, a high percentages of HBV vaccine nonresponders have been reported. We aimed to determine the optimal HBV vaccination protocol. MATERIALS AND METHODS: Kidney transplant waitlisted patients were followed for 12 months and categorized into two groups. Group A included patients with sustained anti-HBs ≥ 10 IU/L who did not require vaccination. Group B consisted of patients with anti-HBs < 10 IU/L who were treated with a course of 4 double-dose HBV vaccinations. Without seroconversion after the first course, a second course was initiated. A third course, coadministered with the tetanus-diphtheria (Td) vaccine, was performed upon failure of the second course. RESULTS: A total of 266 patients were included, 140 were categorized into group A and 126 into group B. Higher serum phosphorus, hemoglobin, and antibodies against the hepatitis core antigen (anti-HBc) were associated with sustaining anti-HBs ≥ 10 IU/L without vaccination. Diabetes mellitus (DM) was associated with the need for vaccination. For group B, 107 patients required 1 course of vaccination, 15 patients required 2 courses, and 4 patients required the third course with Td vaccine coadministration. Long dialysis vintage and low hemoglobin level were associated with seroconversion failure after the first course. CONCLUSION: Serum phosphorus, hemoglobin, DM, anti-HBc, and dialysis vintage were associated with the anti-HBs seroresponsiveness and sustainability. Our 3-course of 4 double-dose HBV vaccines regimen (with Td vaccine in the final course) conferred immunity to all patients.

Interferon-Inducible Protein 10 and Disease Activity in Systemic Lupus Erythematosus and Lupus Nephritis: A Systematic Review and Meta-Analysis.

There is increasing evidence of a correlation between interferon-inducible protein 10 (IP-10) and disease activity of systemic lupus erythematosus (SLE) and lupus nephritis (LN). We conducted a comprehensive search on IP-10 using MEDLINE, Scopus, and Cochrane electronic databases from the beginning to the end of December 2017. All studies that compared serum and/or urine IP-10 between active SLE/LN patients and any control groups were identified and included in this systematic review and meta-analysis. The mean difference (MD) of IP-10 level among active SLE and LN patients, as well as the correlation of IP-10 with disease activity, were meta-analyzed using a random-effects model. From 23 eligible studies, 15 provided adequate data for meta-analysis. Serum IP-10 was significantly elevated in patients with active SLE compared to non-active SLE patients (MD 356.5 pg/mL, 95% CI 59.6 to 653.4, p = 0.019). On the other hand, the levels of serum IP-10 was not different between active LN and non-active LN. However, serum IP-10 was positively correlated with disease activity like SLE disease activity index (SLEDAI) (pooled r = 0.29, 95% CI 0.22 to 0.35, p < 0.001). Furthermore, urine IP-10 tended to be higher in patients with active LN compared to non-active LN patients but this did not reach statistical significance (MD 3.47 pg/mgCr × 100, 95% CI -0.18 to 7.12, p = 0.06). Nevertheless, urine IP-10 was positively correlated with renal SLEDAI (pooled r = 0.29, 95% CI 0.05 to 0.50, p = 0.019). In conclusion, serum and urine IP-10 levels may be useful in monitoring the disease activity of SLE and LN. Serum IP-10 was correlated with systemic disease whereas urine IP-10 was a useful biomarker for detecting active LN.

Down-regulation of let-7a and miR-21 in urine exosomes from lupus nephritis patients during disease flare.

BACKGROUND: The contents of exosomes determine their biological functions and represent a new class of epigenetic modulation of renal cells considering as novel class of biomarker. OBJECTIVE: Our study aims to investigate the expression of microRNAs (miRNA), including miR-10a/b, let-7a, and miR-21, in urinary exosomes isolated from patients with active lupus nephritis (LN) compared to inactive LN. METHODS: The exosomes were obtained from long-term follow up LN patients during active and 4 months after treatment (n = 3). The expression of candidate miRNAs was validated in group of LN patients with renal flare (n = 13) and remission stage (n = 18) using qPCR. All exosomes were characterized by NanoSight and western blotting. The correlation between miRNA expressions and kidney functions was studied. RESULTS: We found that let-7a and miR-21, but not miR-10a/b, were significantly down-regulated in LN patients with active disease compared with inactive disease. Long-term follow-up patients also showed down-regulation of let-7a and miR-21 during disease flare while the expressions were elevated after complete course of treatment. Although the miRNA expressions were not significantly correlated with classical kidney injury markers, negative correlations were found in both protein leakages and glomerular filtration rate. CONCLUSION: Our result suggested that urinary exosome-associated miRNA, let-7a and miR-21, could be used to guide the clinical stage of LN patients and possibly plays a role in epigenetic regulation of the kidney during the disease. Its expression might be able to use as liquid biopsy, however, validation in large sample size is required to show it significant in clinical implication.

The Cytochrome P450 3A5 Non-Expressor Kidney Allograft as a Risk Factor for Calcineurin Inhibitor Nephrotoxicity.

BACKGROUND: Tacrolimus is mainly metabolized by cytochrome P450 3A5 (CYP3A5), which is expressed in the liver. However, CYP3A5 is also expressed in the kidney tissue and may contribute to local tacrolimus clearance in the kidney allograft. We aimed to evaluate the association between the allograft CYP3A5 genotype and transplant outcomes. METHODS: We conducted a retrospective cohort study at the King Chulalongkorn Memorial Hospital, Thailand, comparing 2 groups of donor and recipient CYP3A5 genotypes, the expressor (*1/*1 and *1/*3) and the non-expressor (*3/*3). The primary outcomes were allograft complications including calcineurin inhibitor (CNI) nephrotoxicity and acute rejection episode. RESULTS: Of the 50 enrolled patients, 21 donors were expressors and 29 donors were the non-expressors. Tacrolimus trough concentrations were similar between the 2 genotypes. The incidence of CNI nephrotoxicity was higher in recipients with non-expressor donor genotype compared with the expressor donor genotype (72.4 vs. 33.3%, p = 0.006). CNI nephrotoxicity incidence was not different when recipient's genotypes were compared. Multivariate analysis from Cox-regression showed a hazard ratio of 3.18 (p = 0.026) for CNI nephrotoxicity in the non-expressor compared with the expressor donor. The recipient CYP3A5 genotypes did not significantly contribute to CNI nephrotoxicity. Kaplan-Meier analysis demonstrated the lowest CNI nephrotoxicity-free survival in recipients with the expressor genotype who received allograft from the non-expressor donors (p = 0.005). CONCLUSION: In conclusion, our results suggest that donor CYP3A5 non-expressor genotype (*3/*3) is a risk for CNI nephrotoxicity.

B-cell activating factor, a predictor of antibody mediated rejection in kidney transplantation recipients.

AIM: Donor-specific antibody (DSA) is a widely-used biomarker for antibody-mediated rejection (ABMR) but correctly indicates only 30-40% of patients with ABMR. Additional biomarkers of ABMR in kidney transplant recipients are needed. METHODS: All 68 kidney transplanted-recipients enrolled in this study were negative for graft rejection as determined by surveillance-biopsy ELISA at day 7 post-transplantation. Allograft biopsy was then performed at 6 months post-transplantation for subclinical-ABMR detection. Recipients were stratified by pre-transplant DSA and BAFF at day 7 into four groups. RESULTS: During the study period, 13.2% of the recipients demonstrated subclinical-ABMR at 6 months, without patient with clinical ABMR presentations. Overall mean BAFF at day 7 was 393 pg/mL (95% CI = 316-471 pg/mL). The optimal cut-off value for low vs. high BAFF level was 573 pg/mL, with sensitivity and specificity at 77.8% and 88.1%, respectively. Fifty percent of recipients with high BAFF at day 7 (14 patients) and only 3.7% of patients with low BAFF demonstrated ABMR (P < 0.05). Indeed, ABMR was more common in patients high BAFF level (hazard ratio = 7.30; 95% CI = 3.77-14.15). The prevalence of ABMR among negative pre-transplant DSA/low BAFF, positive DSA/low BAFF, negative DSA/high BAFF, and positive DSA/ high BAFF recipients were 4.4, 0, 37.5 and 66.7%, respectively (P < 0.05). CONCLUSIONS: Post-transplant ABMR can be predicted by perioperative serum BAFF level. Together with DSA testing, BAFF provides additional predictive value for ABMR.

Meta-analysis of GWAS on two Chinese populations followed by replication identifies novel genetic variants on the X chromosome associated with systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease that affects mainly females. What role the X chromosome plays in the disease has always been an intriguing question. In this study, we examined the genetic variants on the X chromosome through meta-analysis of two genome-wide association studies (GWAS) on SLE on Chinese Han populations. Prominent association signals from the meta-analysis were replicated in 4 additional Asian cohorts, with a total of 5373 cases and 9166 matched controls. We identified a novel variant in PRPS2 on Xp22.3 as associated with SLE with genome-wide significance (rs7062536, OR = 0.84, P = 1.00E-08). Association of the L1CAM-MECP2 region with SLE was reported previously. In this study, we identified independent contributors in this region in NAA10 (rs2071128, OR = 0.81, P = 2.19E-13) and TMEM187 (rs17422, OR = 0.75, P = 1.47E-15), in addition to replicating the association from IRAK1-MECP2 region (rs1059702, OR = 0.71, P = 2.40E-18) in Asian cohorts. The X-linked susceptibility variants showed higher effect size in males than that in females, similar to results from a genome-wide survey of associated SNPs on the autosomes. These results suggest that susceptibility genes identified on the X chromosome, while contributing to disease predisposition, might not contribute significantly to the female predominance of this prototype autoimmune disease.

Rituximab for recurrent IgA nephropathy in kidney transplantation: A report of three cases and proposed mechanisms.

AIM: Recurrent IgA nephropathy (IgAN) is a common recurrent glomerular disease after kidney transplantation. Recurrent IgAN, in particular, with crescent formation or endocapillary proliferation might result in kidney allograft loss. However, the current treatment options of recurrent IgAN are conflicting. METHODS: We have reported three kidney-transplanted recipients with biopsy-proven recurrent IgAN treated with four consecutive months of rituximab at the dose of 375 mg/1.73m2 without corticosteroids. RESULTS: At median follow-up 20 months following rituximab administration, all three recipients demonstrated decrease in proteinuria severity, slow disease progression with a well-tolerated condition. This therapeutic effect is most probably mediated by the B cell depletion. CONCLUSION: Our three case reports suggest that the disease severity of recurrent IgAN with endocapillary proliferation regardless of crescent formation can be minimized by the four doses of monthly rituximab regimen.

Urine neutrophil gelatinase-associated lipocalin to predict renal response after induction therapy in active lupus nephritis.

BACKGROUND: Tubulointerstitial injury is important to predict the progression of lupus nephritis (LN). Urine neutrophil gelatinase-associated lipocalin (NGAL) has been reported to detect worsening LN disease activity. Thus, urine NGAL may predict renal outcomes among lupus patients. METHODS: We conducted a prospective multi-center study among active LN patients with biopsy-proven. All patients provided urine samples for NGAL measurement by ELISA collected from all patients at baseline and at 6-month follow-up after induction therapy. RESULTS: In all, 68 active LN patients were enrolled (mean age 31.7 ± 10.0 years, median UPCR 4.8 g/g creatinine level with interquartile range (IQR) 2.5 to 6.9 and mean estimated glomerular filtration rate (GFR) 89.6 ± 33.7 mL/min/1.73 m2). At baseline measurement, median urinary NGAL in complete response, partial response and nonresponse groups was 10.86 (IQR; 6.16, 22.4), 19.91 (IQR; 9.05, 41.91) and 65.5 (IQR; 18.3, 103) ng/mL, respectively (p = 0.006). Urinary NGAL (ng/mL) correlated positively with proteinuria and blood pressure, and correlated negatively with serum complement C3 level and estimated GFR. Based on ROC analysis, urinary NGAL (AUC; 0.724, 95%CI 0.491-0.957) outperformed conventional biomarkers (serum creatinine, urine protein, and GFR) in differentiating complete and partial response groups from the nonresponse group. The urine NGAL cut-off value in the ROC curve, 28.08 ng/mL, discriminated nonresponse with 72.7% sensitivity and 68.4% specificity. CONCLUSION: Urine NGAL at baseline performed better than conventional markers in predicting a clinical response to treatment of active LN except serum complement C3 level. It may have the potential to predict poor response after induction therapy.

A machine learning strategy for predicting localization of post-translational modification sites in protein-protein interacting regions.

BACKGROUND: One very important functional domain of proteins is the protein-protein interacting region (PPIR), which forms the binding interface between interacting polypeptide chains. Post-translational modifications (PTMs) that occur in the PPIR can either interfere with or facilitate the interaction between proteins. The ability to predict whether sites of protein modifications are inside or outside of PPIRs would be useful in further elucidating the regulatory mechanisms by which modifications of specific proteins regulate their cellular functions. RESULTS: Using two of the comprehensive databases for protein-protein interaction and protein modification site data (PDB and PhosphoSitePlus, respectively), we created new databases that map PTMs to their locations inside or outside of PPIRs. The mapped PTMs represented only 5 % of all known PTMs. Thus, in order to predict localization within or outside of PPIRs for the vast majority of PTMs, a machine learning strategy was used to generate predictive models from these mapped databases. For the three mapped PTM databases which had sufficient numbers of modification sites for generating models (acetylation, phosphorylation, and ubiquitylation), the resulting models yielded high overall predictive performance as judged by a combined performance score (CPS). Among the multiple properties of amino acids that were used in the classification tasks, hydrophobicity was found to contribute substantially to the performance of the final predictive models. Compared to the other classifiers we also evaluated, the SVM provided the best performance overall. CONCLUSIONS: These models are the first to predict whether PTMs are located inside or outside of PPIRs, as demonstrated by their high predictive performance. The models and data presented here should be useful in prioritizing both known and newly identified PTMs for further studies to determine the functional relationship between specific PTMs and protein-protein interactions. The implemented R package is available online ( http://sysbio.chula.ac.th/PtmPPIR ).

Three SNPs in chromosome 11q23.3 are independently associated with systemic lupus erythematosus in Asians.

Systemic lupus erythematosus (SLE) has a complex etiology and is affected by both genetic and environmental factors. Although more than 40 loci have shown robust association with SLE, the details of these loci, such as the independent contributors and the genes involved, are still unclear. In this study, we performed meta-analysis of two existing genome-wide association studies (GWASs) on Chinese Han populations from Hong Kong and Anhui, China, and followed the findings by further replication on three additional Chinese and Thailand cohorts with a total of 4254 cases and 6262 controls matched geographically and ethnically. We discovered multiple susceptibility variants for SLE in the 11q23.3 region, including variants in/near PHLDB1 (rs11603023, P(_combined) = 1.25E-08, OR = 1.20), DDX6 (rs638893, P(_combined) = 5.19E-07, OR = 1.22) and CXCR5 (rs10892301, P(_combined) = 2.51E-08, OR = 0.85). Genetic contributions from the newly identified variants were all independent of SNP rs4639966, whose association was reported from the previous GWAS. In addition, the three newly identified variants all showed independent association with the disease through modeling by both stepwise and conditional logistic regression. The presence of multiple independent variants in this region emphasizes its role in SLE susceptibility, and also hints the possibility that distinct biological mechanisms might be involved in the disease involving this genomic region.