Citations

Senescent cells accumulate in fat with aging. We previously found genetic clearance of senescent cells from progeroid INK-ATTAC mice prevents lipodystrophy. Here we show that primary human senescent fat progenitors secrete activin A and directly inhibit adipogenesis in non-senescent progenitors. Blocking activin A partially restored lipid accumulation and expression of key adipogenic markers in differentiating progenitors exposed to senescent cells. Mouse fat tissue activin A increased with aging. Clearing senescent cells from 18-month-old naturally-aged INK-ATTAC mice reduced circulating activin A, blunted fat loss, and enhanced adipogenic transcription factor expression within 3 weeks. JAK inhibitor suppressed senescent cell activin A production and blunted senescent cell-mediated inhibition of adipogenesis. Eight weeks-treatment with ruxolitinib, an FDA-approved JAK1/2 inhibitor, reduced circulating activin A, preserved fat mass, reduced lipotoxicity, and increased insulin sensitivity in 22-month-old mice. Our study indicates targeting senescent cells or their products may alleviate age-related dysfunction of progenitors, adipose tissue, and metabolism.

Significance A hallmark of aging is chronic sterile inflammation, which is closely associated with frailty and age-related diseases. We found that senescent fat progenitor cells accumulate in adipose tissue with aging and acquire a senescence-associated secretory phenotype (SASP), with increased production of proinflammatory cytokines compared with nonsenescent cells. These cells provoked inflammation in adipose tissue and induced macrophage migration. The JAK pathway is activated in adipose tissue with aging, and the SASP can be suppressed by inhibiting the JAK pathway in senescent cells. JAK1/2 inhibitors reduced inflammation and alleviated frailty in aged mice. One possible mechanism contributing to reduced frailty is SASP inhibition. Our study points to the JAK pathway as a potential target for countering age-related dysfunction.

In complex health care situations, teamwork becomes immensely integral to favorable patient outcomes. This study examines an unusual prolonged resuscitation case to understand elements that contributed to the successful outcome of this patient. Through use of the Shared Mental Model Framework (SMMF), we highlighted the importance of multidisciplinary teamwork during resuscitation efforts by analyzing team members’ perceptions through surveys. An 11-item open-ended questionnaire was administered to clinicians (N=9) involved in the resuscitation effort. A case analysis technique was used to identify four key themes that contributed to the success of this resuscitation effort: (1) clear goals are essential to the team’s functioning; (2) strong and effective communication solidified longitudinally among team members; (3) provider’s expertise was paramount to the case’s success; and (4) resources readily available helped manage the team’s cohesiveness. Identifying key teamwork elements in successful resuscitation efforts further informs the valuable need for team cohesiveness in health care.

Mixed lineage kinase 3 (MLK3) deficiency reduces macrophage‐associated inflammation in a murine model of nonalcoholic steatohepatitis (NASH). However, the mechanistic links between MLK3 activation in hepatocytes and macrophage‐driven inflammation in NASH are uncharted. Herein, we report that MLK3 mediates the release of (C‐X‐C motif) ligand 10 (CXCL10)‐laden extracellular vesicles (EVs) from lipotoxic hepatocytes, which induce macrophage chemotaxis. Primary mouse hepatocytes (PMHs) and Huh7 cells were treated with palmitate or lysophosphatidylcholine (LPC). Released EVs were isolated by differential ultracentrifugation. LPC treatment of PMH or Huh7 cells induced release of EVs, which was prevented by either genetic or pharmacological inhibition of MLK3. Mass spectrometry identified the potent chemokine, CXCL10, in the EVs, which was markedly enriched in EVs isolated from LPC‐treated hepatocytes versus untreated cells. Green fluorescent protein (GFP)‐tagged CXCL10 was present in vesicular structures and colocalized with the red fluorescent protein (RFP)‐tagged EV marker, CD63, after LPC treatment of cotransfected Huh‐7 cells. Either genetic deletion or pharmacological inhibition of MLK3 prevented CXCL10 enrichment in EVs. Treatment of mouse bone‐marrow–derived macrophages with lipotoxic hepatocyte‐derived EVs induced macrophage chemotaxis, an effect blocked by incubation with CXCL10‐neutralizing antisera. MLK3‐deficient mice fed a NASH‐inducing diet had reduced concentrations of total plasma EVs and CXCL10 containing EVs compared to wild‐type mice. Conclusions: During hepatocyte lipotoxicity, activated MLK3 induces the release of CXCL10‐bearing vesicles from hepatocytes, which are chemotactic for macrophages. (Hepatology 2016;63:731–744)

Purpose Given that the clinical course of oxaliplatin-induced neuropathy is not well defined, the current study was performed to better understand clinical parameters associated with its presentation. Methods Acute and chronic neuropathy was evaluated in patients receiving adjuvant FOLFOX (fluorouracil, leucovorin, and oxaliplatin) on study N08CB (North Central Cancer Treatment Group, Alliance). Acute neuropathy was assessed by having patients complete daily questionnaires for 6 days with each cycle of FOLFOX. Before each dose of FOLFOX and as long as 18 months after chemotherapy cessation, chronic neurotoxicity was assessed with use of the 20-item, European Organisation for Research and Treatment of Cancer quality-of-life questionnaire for patients with chemotherapy-induced peripheral neuropathy. Results Three hundred eight (89%) of the 346 patients had at least one symptom of acute neuropathy with the first cycle of FOLFOX; these symptoms included sensitivity to touching cold items (71%), sensitivity to swallowing cold items (71%), throat discomfort (63%), or muscle cramps (42%). Acute symptoms peaked at day 3 and improved, although they did not always resolve completely between treatments. These symptoms were about twice as severe in cycles 2 through 12 as they were in cycle 1. For chronic neurotoxicity, tingling was the most severe symptom, followed by numbness and then pain. During chemotherapy, symptoms in the hands were more prominent than they were in the feet; by 18 months, symptoms were more severe in the feet than they were in the hands. Patients with more severe acute neuropathy during the first cycle of therapy experienced more chronic sensory neurotoxicity (P < .0001). Conclusion Acute oxaliplatin-induced neuropathy symptoms do not always completely resolve between treatment cycles and are only half as severe on the first cycle as compared with subsequent cycles. There is a correlation between the severities of acute and chronic neuropathies.