Sequencing of LRP2 Reveals Multiple Rare Variants Associated with Urinary Trefoil Factor-3

Novel biomarkers are being investigated to identify patients with kidney disease. We measured a panel of 13 urinary biomarkers in participants from the Offspring Cohort of the Framingham Heart Study. Using an Affymetrix chip with imputation to 2.5 M single-nucleotide polymorphisms (SNPs), we conducted a GWAS of these biomarkers (n=2640) followed by exonic sequencing and genotyping. Functional studies in zebrafish were used to investigate histologic correlation with renal function. Across all 13 biomarkers, there were 97 significant SNPs at three loci. Lead SNPs at each locus were rs6555820 (P=6.7×10⁻⁴⁹; minor allele frequency [MAF]=0.49) in HAVCR1 (associated with kidney injury molecule-1), rs7565788 (P=2.15×10⁻¹⁶; MAF=0.22) in LRP2 (associated with trefoil factor 3 [TFF3]), and rs11048230 (P=4.77×10⁻⁸; MAF=0.10) in an intergenic region near RASSF8 (associated with vascular endothelial growth factor). Validation in the CKDGen Consortium (n=67,093) showed that only rs7565788 at LRP2, which encodes megalin, was associated with eGFR (P=0.003). Sequencing of exons 16–72 of LRP2 in 200 unrelated individuals at extremes of urinary TFF3 levels identified 197 variants (152 rare; MAF<0.05), 31 of which (27 rare) were nonsynonymous. In aggregate testing, rare variants were associated with urinary TFF3 levels (P=0.003), and the lead GWAS signal was not explained by these variants. Knockdown of LRP2 in zebrafish did not alter the renal phenotype in static or kidney injury models. In conclusion, this study revealed common variants associated with urinary levels of TFF3, kidney injury molecule-1, and vascular endothelial growth factor and identified a cluster of rare variants independently associated with TFF3.Serum creatinine, as used in most GFR estimating equations, is the primary biomarker of CKD.¹ Creatinine has significant limitations as a biomarker. It is insensitive to early declines in kidney function, and there are important extrarenal factors that influence its concentration, thus increasing the potential for misclassification when it is used to diagnose renal disease.² As a result, novel biomarkers are being investigated that could allow earlier and more accurate diagnosis of CKD.³ It is likely, however, that these biomarkers also have non-GFR determinants, including genetic factors. For example, levels of cystatin C, a novel GFR biomarker, are known to be influenced by both nongenetic factors, such as adiposity and the metabolic syndrome,⁴ and the presence of specific genetic variants in the cystatin C-gene cluster.⁵Genome-wide association studies (GWAS) allow for the evaluation of genetic associations of biomarkers in an unbiased manner. These studies could illuminate previously unrecognized pathways for CKD pathogenesis, thus identifying new potential molecular targets for therapeutic intervention. Multiple variants have been identified in association with kidney function through GWAS,⁶ whereas a variant in CUBN encoding cubilin, a proximal tubular transport protein, has been associated with albuminuria.⁷ Recently, a GWAS identified a locus at PTGDS in association with another kidney biomarker, β-trace protein.⁸To gain additional insight into biologic pathways of renal function and kidney injury, we measured a panel of 13 urinary biomarkers in participants from the Framingham Heart Study (FHS) and performed a GWAS of their levels. Here, we report the primary results from these studies as well as follow-up work to identify whether rare variants in LRP2 are associated with levels of trefoil factor 3 (TFF3).     

Healthcare Intensity at Initiation of Chronic Dialysis among Older Adults

Little is known about the circumstances under which older adults initiate chronic dialysis and subsequent outcomes. Using national registry data, we conducted a retrospective analysis of 416,657 Medicare beneficiaries aged ≥67 years who initiated chronic dialysis between January 1995 and December 2008. Our goal was to define the relationship between health care intensity around the time of dialysis initiation and subsequent survival and patterns of hospitalization, use of intensive procedures (mechanical ventilation, feeding tube placement, and cardiopulmonary resuscitation), and discontinuation of dialysis before death. We found that most patients (64.5%) initiated dialysis in the hospital, including 36.6% who were hospitalized for ≥2 weeks and 7.4% who underwent one or more intensive procedures. Compared with patients who initiated dialysis in the outpatient setting, those who received the highest intensity of care at dialysis initiation (those hospitalized ≥2 weeks and receiving at least one intensive procedure) had a shorter median survival (0.7 versus 2.1 years; P<0.001), spent a greater percentage of remaining follow-up time in the hospital (median, 22.9% versus 3.1%; P<0.001), were more likely to undergo subsequent intensive procedures (44.9% versus 26.0%; adjusted hazard ratio, 2.33; 95% confidence interval [CI], 2.27 to 2.39), and were less likely to have discontinued dialysis before death (19.1% versus 26.2%; adjusted odds ratio, 0.68; 95% CI, 0.65 to 0.72). In conclusion, most older adults initiate chronic dialysis in the hospital. Those who have a prolonged hospital stay and receive other forms of life support around the time of dialysis initiation have limited survival and more intensive patterns of subsequent healthcare utilization.Over the last decade, a growing number of older adults are initiating chronic dialysis.¹ Survival among these older patients is extremely limited,^2,3 and many experience functional decline,^4,5 frequent hospitalization,⁶ and a high symptom burden⁷ after initiation of chronic dialysis. In this setting, patients must often make trade-offs between interventions intended to lengthen life and those directed at other treatment goals, such as maximizing quality of life and maintaining independence.Rates of hospitalization and use of intensive procedures, such as mechanical ventilation, feeding tube placement, and cardiopulmonary resuscitation (CPR), at the end of life are exceptionally high in older dialysis patients compared with other older Medicare beneficiaries with life-limiting illness.⁸ Discussions about prognosis, goals, and preferences are often lacking, and patients may have little appreciation of their likelihood of clinical deterioration or knowledge of more conservative alternatives, such as hospice.⁹ Uncertainty about disease trajectory and prognosis can hamper formulation of future plans and treatment preferences.^10–12Prior studies have evaluated the association of patient characteristics (e.g., comorbid conditions and functional status)^5,13,14 and treatment practices (e.g., early nephrology referral and type of vascular access)^15,16 before and at the time of dialysis initiation with subsequent outcomes. However, many of these analyses did not capture information on clinical circumstances around the time of dialysis initiation. In reality, chronic dialysis is often initiated in the context of acute illness^17,18 and rapid or unexpected loss of renal function.¹⁴We hypothesized that illness severity around the time of dialysis initiation—as reflected in measures of health care intensity, such as length of hospitalization and use of intensive procedures—might provide information useful for anticipatory guidance and supporting treatment decisions in older adults newly initiated on chronic dialysis. To evaluate this hypothesis, we used data from the U.S. Renal Data System (USRDS), a national registry of ESRD, to identify 416,657 Medicare beneficiaries aged ≥67 years and describe the intensity of care they experienced around the time of initiation of chronic dialysis and its association with survival and patterns of future healthcare utilization.     

Predictors associated with nonunion and symptomatic malunion following non-operative treatment of displaced midshaft clavicle fractures—a systematic review of the literature

Purpose

The aim of this study was to survey existing literature in order to identify all reported predictors associated with nonunion or symptomatic malunion in adult patients with displaced midshaft clavicle fractures treated non-operatively.

Method

A systematic literature search in Medline was carried out in order to identify publications in English, reporting on predictors for nonunion and malunion in adults with displaced midshaft clavicle fractures. After applying inclusion and exclusion criteria, eight publications were included in this systematic review.

Results

A total of 2,117 midshaft clavicle fractures were included in the eight publications. All publications reported on predictors for nonunion but none were found to report on predictors for malunion. The studies were characterized by different definitions for nonunion and symptomatic malunion if at all present. A total of 13 potential factors associated with nonunion were identified, six of these (displacement, comminution, shortening, age, gender and smoking) were reported as predictors for nonunion. Outcome definitions varied among the studies.

Conclusion

The included publications varied greatly in design, sample size, and quality. Based on the present literature most of the predictors were found to be of limited evidence, however displacement seems to be the most likely factor that can be used to predict for nonunion. Treating all clavicle fractures with displacement surgically would inevitably lead to overtreatment, which is why future studies need to focus on predictive factors in order to differentiate between patients that would benefit from surgery and those who would not.     

DOUBLE-BLIND PROSPECTIVE RANDOMIZED STUDY COMPARING POLYETHYLENE GLYCOL TO LACTULOSE FOR BOWEL PREPARATION IN COLONOSCOPY

Background

Colonoscopy is the most frequent exam used to evaluate colonic mucosa, allowing the diagnosis and treatment of many diseases. The appropriate bowel preparation is indispensable for the realization of colonoscopy. Therefore, it is necessary the use of laxative medications, preferentially by oral administration.

Aim

To compare two medications used in bowel preparation in adult patients going to ambulatory colonoscopy and to analyze the patients'' profile.

Methods

A double-blind prospective study with 200 patients, randomized in two groups: one that received polyethilene glycol and another that received lactulose. The patients answered to questionnaires to data compilation, as tolerance, symptoms and complications related to preparation. Besides, it was also evaluated the prepare efficacy related to the presence of fecal residue.

Results

Intestinal habit alterations and abdominal pain were the main reasons to realize the exams and hypertension was the most prevalent comorbidity. Ten percent of the ones who received lactulose didn''t get to finish the preparation and 50% considered the taste "bad, but tolerable". The most common subjective symptom after the medication was nausea, especially after lactulose. During the exam, most of the patients who used lactulose had a "light discomfort" and the ones who used polyethilene glycol considered the discomfort as "tolerable". The quality of the preparation was good in 75%, undependable of the medication that was used.

Conclusion

Polyethilene glycol was more tolerable when compared to lactulose, without difference on the quality of the preparation.     

Raman study of the repair of surgical bone defects grafted with biphasic synthetic microgranular HA + β-calcium triphosphate and irradiated or not with λ780 nm laser

The treatment of bone loss due to different etiologic factors is difficult, and many techniques aim to improve repair, including a wide range of biomaterials and, recently, photobioengineering. This work aimed to assess, through Raman spectroscopy, the level of bone mineralization using the intensities of the Raman peaks of both inorganic (～960, ～1,070, and ～1,077 cm^?1) and organic (～1,454 and ～1,666 cm^?1) contents of bone tissue. Forty rats were divided into four groups each subdivided into two subgroups according to the time of killing (15 and 30 days). Surgical bone defects were made on femur of each animal with a trephine drill. On animals of group Clot, the defect was filled only by blood clot; on group Laser, the defect filled with the clot was further irradiated. On animals of groups Biomaterial and Laser?+?Biomaterial, the defect was filled by biomaterial and the last one was further irradiated (λ780 nm, 70 mW, Φ?～?0.4 cm², 20 J/cm² session, 140 J/cm² treatment) in four points around the defect at 48-h intervals and repeated for 2 weeks. At both 15th and 30th day following killing, samples were taken and analyzed by Raman spectroscopy. At the end of the experimental time, the intensities of both inorganic and organic contents were higher on group Laser?+?Biomaterial. It is concluded that the use of laser phototherapy associated to biomaterial was effective in improving bone healing on bone defects as a result of the increasing deposition of calcium hydroxyapatite measured by Raman spectroscopy.     

Membranous glomerulonephritis with crescents

Purpose

The coexistence of membranous glomerulonephritis (MGN) and necrotizing and crescentic glomerulonephritis (NCGN) is an unusual finding in a renal biopsy except in lupus nephritis. Little is known about whether these lesions are causally related in any clinical setting.

Methods

We reviewed the pathology, presentation, and clinical course of 13 non-lupus patients with combined MGN and NCGN in native kidney biopsies (nine females, four males; median age 69 years), with particular attention to evidence of secondary MGN. Additional IgG subclass and phospholipase A2 receptor (PLA2R) immunofluorescence studies were conducted in seven cases.

Results

Eight biopsies were pauci-immune other than the capillary wall deposits of MGN; one patient had a non-lupus immune complex disease, and four had mesangial deposits, including one with rare subendothelial deposits. None had anti-glomerular basement membrane disease. IgG4 was dominant or codominant in the capillary wall deposits in three cases and virtually absent in four; PLA2R was positive in two cases, and negative in five. Seven patients were judged to have secondary MGN, including five of eight ANCA+ patients. Twelve patients were treated with combinations of steroids, cyclophosphamide, rituximab, followed by durable response in seven and relentless progression to end stage renal disease in four.

Conclusions

Secondary MGN occurs with higher frequency in ANCA-positive NCGN than in the general MGN population. A causal relationship between MGN and NCGN was not established in any patient, but circumstances suggest a common cause in several, including immune complex disease, drug reaction and paraneoplastic syndrome.