Cell death in neurodegeneration occurs at the convergence of diverse metabolic pathways. In the retina, a common underlying mechanism involves mitochondrial dysfunction since photoreceptor ...homeostasis and survival are highly susceptible to altered aerobic energy metabolism. We sought to develop an assay to directly measure oxygen consumption in intact retina with the goal of identifying alterations in respiration during photoreceptor dysfunction and degeneration.
Circular punches of freshly isolated mouse retina, adjacent to the optic nerve head, were used in the microplate-based Seahorse Extracellular Flux Analyzer to measure oxygen consumption. Tissue integrity was evaluated by propidium iodide staining and live imaging. Different substrates were tested for mitochondrial respiration. Basal and maximal respiration were expressed as oxygen consumption rate (OCR) and respectively measured in Ames' medium before and after the addition of mitochondrial uncoupler, BAM15.
We show that glucose is an essential substrate for retinal mitochondria. At baseline, mitochondria respiration in the intact wild-type retina was close to maximal, with limited reserve capacity. Similar OCR and limited mitochondrial reserve capacity was also observed in cone-only Nrl-/- retina. However, the retina of Pde6brd1/rd1, Cep290rd16/rd16 and Rpgrip1-/- mice, all with dysfunctional or no photoreceptors, had reduced OCR and higher mitochondrial reserve capacity.
We have optimized a method to directly measure oxygen consumption in acutely isolated, ex vivo mouse retina and demonstrate that photoreceptors have low mitochondrial reserve capacity. Our data provide a plausible explanation for the high vulnerability of photoreceptors to altered energy homeostasis caused by mutations or metabolic challenges.
Aging-associated functional decline is accompanied by alterations in the epigenome. To explore DNA modifications that could influence visual function with age, we perform whole-genome bisulfite ...sequencing of purified mouse rod photoreceptors at four ages and identify 2,054 differentially methylated regions (DMRs). We detect many DMRs during early stages of aging and in rod regulatory regions, and some of these cluster at chromosomal hotspots, especially on chromosome 10, which includes a longevity interactome. Integration of methylome to age-related transcriptome changes, chromatin signatures, and first-order protein-protein interactions uncover an enrichment of DMRs in altered pathways that are associated with rod function, aging, and energy metabolism. In concordance, we detect reduced basal mitochondrial respiration and increased fatty acid dependency with retinal age in ex vivo assays. Our study reveals age-dependent genomic and chromatin features susceptible to DNA methylation changes in rod photoreceptors and identifies a link between DNA methylation and energy metabolism in aging.
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•WGBS identifies 2,054 differentially methylated regions (DMRs) in aging mouse rods•DMRs are present in regulatory regions and cluster at chromosomal hotspots•DMRs are linked to dysregulation of aging pathways and energy metabolism•Old retinas exhibit lower basal respiration and higher fatty acid dependency
The crosstalk between chromatin modifications and aging hallmarks is poorly understood, especially in neurons. Using purified rod photoreceptors, Corso-Díaz et al. identify aging-associated differentially DNA methylated regions that greatly overlap regulatory elements and are linked to lower mitochondrial basal respiration and higher fatty acid dependency.
Abdominal Aortic Aneurysm (AAA) is a highly morbid condition and is the 11th leading cause of death in the United States. Treatment options are limited to operative interventions, with minimal ...non-operative options. Prior literature has demonstrated a benefit to the use of mesenchymal stem cells (MSCs) in attenuating AAA formation. We demonstrate the utility of MSCs in treating AAA in swine, focusing on the mechanical and structural characteristics of aortic tissue after treatment.
16 Yorkshire pigs underwent retroperitoneal exposure of the infrarenal aorta, with subsequent induction of AAA with peri-adventitial elastase and collagenase. A 1 × 4 cm piece of Gelfoam, an absorbable gelatin-based hemostatic agent, was soaked in media or human MSCs and placed directly on the vessel for control and experimental animals. At postoperative day 21, animals were sacrificed and the infrarenal aorta at this location was harvested for analysis. Tensile strength was measured using a tensiometer, from which Young's modulus and maximum strain were calculated.
All animals survived the surgery and post-operative course. Young's elastic modulus for the aneurysm control group was 15.83 ± 1.61 compared to 22.13 ± 2.34 for the stem cell treated segment, p = 0.0316. There was no significant difference in the peak stress between groups.
This is the first study to demonstrate the mechanical effects of stem cell therapy on a model of AAA in swine. Young's modulus, which characterizes the intrinsic capacity of a tissue to withstand stress, was greater in the animals treated with MSCs compared to control animals with aneurysms. This methodology can be utilized in future large animal models to develop cell and drug-based therapies for AAA.
Background
The Asian American, Native Hawaiian, and Pacific Islander (AANHPI) population is among the fastest-growing population in the USA. However, this is not reflected in scientific research, in ...which ethnic groups are often combined. We identified trends in treatment and outcomes for pancreatic cancer in a disaggregated AANHPI population. We hypothesize that patients from different AANHPI groups have differences in survival.
Patients and Methods
A retrospective analysis of the National Cancer Database between 2010 and 2019 identified patients treated for pancreatic cancer. We identified demographic factors for patients of Caucasian, African American, and disaggregated Asian subpopulations. Survival curves were generated and multivariate analysis was performed to help determine which factors impacted overall survival.
Results
A total of 296,448 patients met the inclusion criteria. Of those, 8568 (3%) patients were Asian. Median survival of AANHPI patients was 11.3 months, as compared with Caucasians (8.9 months) and African Americans (8.1 months) (
p
< 0.0001). Asian Indians had the highest median survival (14.3 months), whereas the Japanese subpopulation had the lowest (7.6 months) (
p
< 0.0001). There were significant differences in median survival between the different AANHPI subpopulations irrespective of stage. Multivariate analysis demonstrated that belonging to an AANHPI racial/ethnic group, excluding Japanese and Filipino, was associated with decreased risk of overall mortality.
Discussion
Significant differences were identified in the overall median survival for patients with pancreatic cancer between AANHPI subpopulations. Disparities in socioeconomic factors may have played a role in overall survival. This study highlights the need to include disaggregated data in future studies to subdue disparities in cancer care for patients.
Adoptive cell therapy (ACT) using tumor-infiltrating lymphocytes (TILs) has been gaining promise as a therapeutic option for metastatic melanoma. By harnessing the power of patients’ tumor-resident ...lymphocytes, TIL therapy has shown promise in delivering durable, complete responses for patients who have progressed with other treatments, including checkpoint inhibition. This form of personalized medicine has traditionally been limited to select academic facilities with the infrastructure and resources to generate TIL cells and care for patients during the treatment phase. In this review, the authors discuss the role of TIL therapy for patients with metastatic melanoma, including the current state of therapeutic options, logistics of TIL harvest and infusion, management of infusion-specific toxicities, and foundational steps for surgeons and oncologists to establish cell-based therapies in individual hospitals and cancer centers.
Background
Colostomy reversal is a common procedure. Patients often have baseline comorbidities associated with postoperative morbidity. We utilized a modified frailty index (mFI-5) to predict ...postoperative complications.
Methods
Patients who underwent elective, open Hartmann’s reversal were queried from the National Surgical Quality Improvement Program (NSQIP) database. Patients were stratified to low, medium, or high frailty groups. Statistical analysis was performed using chi-squared, ANOVA, and logistic regression.
Results
There were 9272 patients with Hartmann’s reversal. 48.78%, 30.31%, and 12.89% had low, moderate, or high frailty, respectively. High frailty was associated with cardiac arrest, myocardial infarction, reintubation, prolonged intubation, early reoperation, and mortality. After multivariate analysis, high frailty was associated with prolonged intubation (OR 3.147, P = .001), reintubation (OR 2.548, P = .002), and reoperation (OR 1.67, P < .001).
Conclusions
Frailty was associated with greater risk of postoperative complications in patients undergoing Hartmann’s reversal. Frailty may be a useful adjunct to stratify for patients who are at risk for postoperative complications.
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