Altered lung metabolism and mitochondrial DAMPs in lung injury due to acute kidney injury.

Acute respiratory distress syndrome (ARDS) is a common cause of mortality in patients with acute kidney injury (AKI). Inflammatory crosstalk from the kidney to the lung has been shown to contribute to lung injury after AKI, but anti-inflammatory therapies have not been proven beneficial in human studies. Recently, AKI was shown to alter mitochondria and related metabolic pathways in the heart, but the impact of AKI on lung metabolism has not been investigated to our knowledge. In this study, we evaluated the metabolomic profile of the lung following renal ischemia and reperfusion to identify novel pathways that may be modifiable. We randomized C57BL/6 mice to 20 minutes of bilateral renal arterial clamping or sham operation under ketamine/xylazine anesthesia. At 4 hours after reperfusion, we found a significant increase in markers of lung injury, as well as significant metabolomic changes across lung, kidney, plasma and bronchoalveolar lavage fluid (BALF) compared to shams. Comparative analyses revealed that the fatty acid oxidation pathway was the most significantly altered metabolic pathway, a finding which is consistent with mitochondrial dysfunction systemically and in the lung. These metabolomic changes correlated with the extracellular accumulation of the mitochondrial damage associated molecular patterns (mtDAMPs), mitochondrial DNA (mtDNA) and transcription factor A, mitochondria (TFAM). Finally, we found that intraperitoneal injection of renal mtDAMPs caused metabolomic changes consistent with mitochondrial dysfunction in the lung in vivo. Mitochondrial function and mtDAMPs warrant further investigation as potential therapeutic targets in preventing lung injury because of AKI.

Neighborhood-level Disparities in Achievement of Social Continence Among School-aged Children With Anorectal Malformations: A Single-center Retrospective Study.

BACKGROUND: Fecal incontinence is a common problem for children with repaired anorectal malformations (ARM) and has significant implications for initiating school. While sex, anatomy, and medical comorbidities are known to influence continence outcomes, the impact of socioeconomic factors and neighborhood-level disadvantage are less well understood. METHODS: We performed a single-center retrospective review of all school-aged (5-18 years) children with ARM at a longitudinal pediatric surgery clinic. Demographic, clinical, and socioeconomic variables were abstracted via chart review and geocoding was performed to obtain Area Deprivation Index (ADI) and Social Vulnerability Index (SVI) scores. Statistical analyses assessed for associations between the primary outcome of social continence (defined as no diaper usage and infrequent fecal accidents at age 5) and these variables. RESULTS: 72 patients were included; of these, 45.8% were socially continent. On bivariate analysis, social continence was significantly associated with state ADI score as well as the SVI Housing characteristics score. These associations remained significant when adjusting for sex and medical comorbidities in separate multiple logistic regression models. CONCLUSION: The relative disadvantage of the neighborhood in which a child with ARM lives may play a role in their ability to achieve continence by school age. Efforts are warranted to identify and develop targeted interventions to for this pediatric population. LEVEL OF EVIDENCE: IV.

Evidence for repeat-induced gene silencing in cultured Mammalian cells: inactivation of tandem repeats of transfected genes.

Foreign DNA can be readily integrated into the genomes of mammalian embryonic cells by retroviral infection, DNA microinjection, and transfection protocols. However, the transgenic DNA is frequently not expressed or is expressed at levels far below expectation. In a number of organisms such as yeast, plants, Drosophila, and nematodes, silencing of transfected genes is triggered by the interaction between adjacent or dispersed copies of genes of identical sequence. We set out to determine whether a mechanism similar to repeat-induced gene silencing (RIGS) is responsible for the silencing of transgenes in murine embryonal carcinoma stem cells. We compared the expression of identical reporter gene constructs in cells carrying single or multiple copies and found that the level of expression per integrated copy was more than 10-fold higher in single-copy integrants. In cells carrying tandem copies of the transgene, many copies were methylated and clones frequently failed to express both copies of near-identical integrated alleles. Addition of extra copies of the reporter gene coding sequence reduced the level of expression from the same reporter driven by a eukaryotic promoter. We also found that inhibitors of histone deacetylase such as trichostatin A forestall the silencing of multicopy transgenes, suggesting that chromatin mediates the silencing of transfected genes. This evidence is consistent with the idea that RIGS does occur in mammalian embryonic stem cells although silencing of single-copy transgenes also occurs, suggesting that RIGS is only one of the mechanisms responsible for triggering transgene silencing.