High Protein Intake Associates with Cardiovascular Events but not with Loss of Renal Function

The long-term effects of higher dietary protein intake on cardiovascular and renal outcomes in the general population are not clear. We analyzed data from 8461 individuals who did not have renal disease and participated in two or three subsequent screenings (6.4-yr follow-up) in a prospective, community-based cohort study (Prevention of Renal and Vascular ENd-stage Disease [PREVEND]). We calculated daily protein intake from 24-h urinary urea excretion (Maroni formula) and used Cox proportional hazard models to analyze the associations between protein intake, cardiovascular events, and mortality. We used mixed-effects models to investigate the association between protein intake and change in renal function over time. The mean ± SD daily protein intake was 1.20 ± 0.27 g/kg. Protein intake was significantly associated with cardiovascular events during follow-up. The associations seemed U-shaped; compared with intermediate protein intake, individuals with either higher or lower protein intake had higher event rates. All-cause mortality and noncardiovascular mortality also were significantly associated with protein intake; individuals with low protein intake had the highest event rates. We found no association between baseline protein intake and rate of renal function decline during follow-up. In summary, in the general population, high protein intake does not promote accelerated decline of renal function but does associate with an increased risk for cardiovascular events

Airway inflammation contributes to health status in COPD:a cross-sectional study

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized by irreversible airflow limitation and airway inflammation, accompanied by decreased health status. It is still unknown which factors are responsible for the impaired health status in COPD. We postulated that airway inflammation negatively contributes to health status in COPD. METHODS: In 114 COPD patients (99 male, age: 62 ± 8 yr, 41 [31–55] pack-years, no inhaled or oral corticosteroids, postbronchodilator FEV(1): 63 ± 9% pred, FEV(1)/IVC: 48 ± 9%) we obtained induced sputum and measured health status (St. George's respiratory questionnaire (SGRQ)), postbronchodilator FEV(1), hyperinflation (RV/TLC), and airway hyperresponsiveness to methacholine (PC(20)). Sputum was induced by hypertonic saline and differential cell counts were obtained in 102 patients. RESULTS: Univariate analysis showed that SGRQ total and symptom score were positively associated with % sputum macrophages (r = 0.20, p = 0.05; and r = 0.20, p = 0.04, respectively). Multiple regression analysis confirmed these relationships, providing significant contributions of % sputum macrophages (B = 0.25, p = 0.021) and RV/TLC (B = 0.60, p = 0.002) to SGRQ total score. Furthermore, SGRQ symptom score was associated with % sputum macrophages (B = 0.30, p = 0.03) and RV/TLC (B = 0.48, p = 0.044), whilst SGRQ activity score was associated with % sputum macrophages (B = 0.46, p = 0.002), RV/TLC (B = 0.61, p = 0.015), and PC(20 )(B = -9.3, p = 0.024). Current smoking and FEV(1 )were not significantly associated with health status in the multiple regression analysis. CONCLUSION: We conclude that worse health status in COPD patients is associated with higher inflammatory cell counts in induced sputum. Our findings suggest that airway inflammation and hyperinflation independently contribute to impaired health status in COPD. This may provide a rationale for anti-inflammatory therapy in this disease

CRISPR interference to evaluate modifiers of C9ORF72-mediated toxicity in FTD

Treatments for neurodegenerative disease, including Frontotemporal dementia (FTD) and Amyotrophic lateral sclerosis (ALS), remain rather limited, underscoring the need for greater mechanistic insight and disease-relevant models. Our ability to develop novel disease models of genetic risk factors, disease modifiers, and other FTD/ALS-relevant targets is impeded by the significant amount of time and capital required to develop conventional knockout and transgenic mice. To overcome these limitations, we have generated a novel CRISPRi interference (CRISPRi) knockin mouse. CRISPRi uses a catalytically dead form of Cas9, fused to a transcriptional repressor to knockdown protein expression, following the introduction of single guide RNA against the gene of interest. To validate the utility of this model we have selected the TAR DNA binding protein (TDP-43) splicing target, stathmin-2 (STMN2). STMN2 RNA is downregulated in FTD/ALS due to loss of TDP-43 activity and STMN2 loss is suggested to play a role in ALS pathogenesis. The involvement of STMN2 loss of function in FTD has yet to be determined. We find that STMN2 protein levels in familial FTD cases are significantly reduced compared to controls, supporting that STMN2 depletion may be involved in the pathogenesis of FTD. Here, we provide proof-of-concept that we can simultaneously knock down Stmn2 and express the expanded repeat in the Chromosome 9 open reading frame 72 (C9ORF72) gene, successfully replicating features of C9-associated pathology. Of interest, depletion of Stmn2 had no effect on expression or deposition of dipeptide repeat proteins (DPRs), but significantly decreased the number of phosphorylated Tdp-43 (pTdp-43) inclusions. We submit that our novel CRISPRi mouse provides a versatile and rapid method to silence gene expression in vivo and propose this model will be useful to understand gene function in isolation or in the context of other neurodegenerative disease models

Case Reports1. A Late Presentation of Loeys-Dietz Syndrome: Beware of TGFβ Receptor Mutations in Benign Joint Hypermobility

Background: Thoracic aortic aneurysms (TAA) and dissections are not uncommon causes of sudden death in young adults. Loeys-Dietz syndrome (LDS) is a rare, recently described, autosomal dominant, connective tissue disease characterized by aggressive arterial aneurysms, resulting from mutations in the transforming growth factor beta (TGFβ) receptor genes TGFBR1 and TGFBR2. Mean age at death is 26.1 years, most often due to aortic dissection. We report an unusually late presentation of LDS, diagnosed following elective surgery in a female with a long history of joint hypermobility. Methods: A 51-year-old Caucasian lady complained of chest pain and headache following a dural leak from spinal anaesthesia for an elective ankle arthroscopy. CT scan and echocardiography demonstrated a dilated aortic root and significant aortic regurgitation. MRA demonstrated aortic tortuosity, an infrarenal aortic aneurysm and aneurysms in the left renal and right internal mammary arteries. She underwent aortic root repair and aortic valve replacement. She had a background of long-standing joint pains secondary to hypermobility, easy bruising, unusual fracture susceptibility and mild bronchiectasis. She had one healthy child age 32, after which she suffered a uterine prolapse. Examination revealed mild Marfanoid features. Uvula, skin and ophthalmological examination was normal. Results: Fibrillin-1 testing for Marfan syndrome (MFS) was negative. Detection of a c.1270G > C (p.Gly424Arg) TGFBR2 mutation confirmed the diagnosis of LDS. Losartan was started for vascular protection. Conclusions: LDS is a severe inherited vasculopathy that usually presents in childhood. It is characterized by aortic root dilatation and ascending aneurysms. There is a higher risk of aortic dissection compared with MFS. Clinical features overlap with MFS and Ehlers Danlos syndrome Type IV, but differentiating dysmorphogenic features include ocular hypertelorism, bifid uvula and cleft palate. Echocardiography and MRA or CT scanning from head to pelvis is recommended to establish the extent of vascular involvement. Management involves early surgical intervention, including early valve-sparing aortic root replacement, genetic counselling and close monitoring in pregnancy. Despite being caused by loss of function mutations in either TGFβ receptor, paradoxical activation of TGFβ signalling is seen, suggesting that TGFβ antagonism may confer disease modifying effects similar to those observed in MFS. TGFβ antagonism can be achieved with angiotensin antagonists, such as Losartan, which is able to delay aortic aneurysm development in preclinical models and in patients with MFS. Our case emphasizes the importance of timely recognition of vasculopathy syndromes in patients with hypermobility and the need for early surgical intervention. It also highlights their heterogeneity and the potential for late presentation. Disclosures: The authors have declared no conflicts of interes

Development and validation of a general population renal risk score

Background and objectives There is a need for prediction scores that identify individuals at increased risk for developing progressive chronic kidney disease (CKD). Therefore, this study was performed to develop and validate a "renal risk score" for the general population. Design, setting, participants, & measurements For this study we used data from the PREVEND (Prevention of Renal and Vascular ENdstage Disease) study, a prospective population-based cohort study with a median follow-up of 6.4 years. Participants with two or three consecutive estimated GFR (eGFR) measurements during follow-up were included. Participants within the group who had the most renal function decline (top 20% of the total population) and had an eGFR value <60 ml/min per 1.73 m(2) during follow-up were defined as having progressive CKD. Possible predictors for progressive CKD were selected on the basis of univariable logistic regression analyses. Results A final prediction model was built using backward logistic regression analysis. Besides baseline eGFR, the model contained age, urinary albumin excretion, systolic BP, C-reactive protein, and known hypertension. The area under the receiver operating characteristic (ROC) curve was 0.84. We performed internal validation by using a bootstrapping procedure. As expected, after the regression coefficients were corrected for optimism, the area under the ROC curve was still 0.84. For clinical use we divided all predictors in meaningful clinical categories to develop a score chart. The area under the ROC curve was 0.83, indicating the high discriminative value of this model. Conclusions Given the high internal validity of this renal risk score, this score can be helpful to identify individuals at increased risk for progressive CKD. Clin J Am Soc Nephrol 6: 1731-1738, 2011. doi: 10.2215/CJN.08590910

Gender differences in predictors of the decline of renal function in the general population

We sought to identify predictors of the decline in renal function, especially those that are modifiable, in the 5488 participants of the prospective, community-based cohort study PREVEND who completed three visits during a mean follow-up of 6.5 years. The change in renal function was used as the outcome and this was calculated as the linear regression of three estimated GFR measurements obtained during follow-up. Risk factors, known to influence renal outcome in patients with primary renal diseases, were used as potential predictors in multivariate regression analyses. High systolic blood pressure and plasma glucose were found to be independent predictors for an accelerated decline in function for both genders. In males, albuminuria was the strongest independent predictor for renal function decline, whereas in females albuminuria was univariately associated only after adjustment for age. The direction of the association between cholesterol/HDL ratio and decline of renal function differed by gender. Surprisingly, in males, waist circumference was an independent predictor and positively associated with renal function outcome. These studies show that there are gender differences in the standard predictors of the decline in renal function

Loss of Infliximab Into Feces Is Associated With Lack of Response to Therapy in Patients With Severe Ulcerative Colitis

It is not clear why some patients with ulcerative colitis (UC) do not respond to treatment with anti-tumor necrosis factor (TNF) agents, such as infliximab. It could be that some patients have high level of inflammation, with large quantities of TNF to be neutralized by the drug. We investigated whether loss of anti-TNF agents through ulcerated intestinal mucosa reduces the efficacy of these drugs in patients with severe UC. We collected fecal samples from 30 consecutive patients with moderate to severely active UC during the first 2 weeks of infliximab therapy at the University of Amsterdam hospital. Infliximab concentrations were measured in serum and supernatants of fecal samples using an enzyme-linked immunosorbent assay (Sanquin Biologicals Laboratory, Amsterdam, The Netherlands). Clinical and endoscopic responses were assessed 2 and 8 weeks and 3 months after treatment began. Infliximab was detected in 129 of 195 fecal samples (66%); the highest concentrations were measured in the first days after the first infusion. Patients that were clinical nonresponders at week 2 had significantly higher fecal concentrations of infliximab after the first day of treatment than patients with clinical responses (median concentration, 5.01 μg/mL in nonresponders vs 0.54 μg/mL in responders; P = .0047). We did not observe a correlation between fecal and serum concentrations of infliximab. Infliximab is lost into stools of patients with UC. High fecal concentrations of infliximab in the first days after therapy begins are associated with primary nonresponse. Additional studies are needed to determine how therapeutic antibodies are lost through the intestinal mucosa and how this process affects treatment response. Clinical trial ID: NL41310.018.1

Pharmacokinetic Features and Presence of Antidrug Antibodies Associate With Response to Infliximab Induction Therapy in Patients With Moderate to Severe Ulcerative Colitis

The pharmacokinetics of infliximab during induction treatment for ulcerative colitis (UC) have not been studied. We investigated serum concentrations of infliximab and the early appearance of antibodies to infliximab (ATI) during induction treatment in patients with moderate-to-severe UC. We performed a prospective analysis of 19 consecutive patients with moderate-severe UC (endoscopic Mayo ≥ 2) receiving induction therapy with infliximab (5 mg/kg at weeks 0, 2, and 6) at 2 centers in Amsterdam, The Netherlands, from July 2012 through March 2014. Serial serum and fecal samples were collected for 6 weeks and concentrations of infliximab, ATI, c-reactive protein (CRP), albumin, and fecal calprotectin were measured. Treatment success was defined as endoscopic response (≥ 1 point reduction in the endoscopic Mayo score) at week 8. Eleven patients (58%) had an endoscopic response. The median serum concentrations of infliximab at week 6 were 8.1 μg/mL in responders (interquartile range, 3.0-13.7 μg/mL) and 2.9 μg/mL in nonresponders (interquartile range, 0.01-5.8 μg/mL) (P = .03). ATIs were detected in 7 patients as early as day 18 (median, 28 d; interquartile range, 18-42 d). Six of the 8 nonresponders tested positive for ATIs vs 1 of 11 responders (P <.01; odds ratio, 30.0; 95% CI, 2.2-406.2). Patients with a baseline concentration of CRP greater than 50 mg/L had lower drug exposure from weeks 0 to 6 (587 mg/L/d in patients with high levels of CRP vs 1361 mg/L/day in patients with low CRP; P = .001). The median area under the curve for serum concentration of infliximab during induction therapy was 1230 mg/L/d in nonresponders vs 1352 mg/L/d in responders (P = .65). There is a significant difference in serum concentration of infliximab at week 6 of treatment between responders and nonresponders. Early development of ATIs during induction therapy reduces the serum concentration of infliximab and is associated with nonresponse to treatment. Patients with high baseline serum levels of CRP had lower serum concentrations of infliximab. NL39626.018.1