Glyoxalase 1 Prevents Chronic Hyperglycemia Induced Heart-Explant Derived Cell Dysfunction.

Decades of work have shown that diabetes increases the risk of heart disease and worsens clinical outcomes after myocardial infarction. Because diabetes is an absolute contraindication to heart transplant, cell therapy is increasingly being explored as a means of improving heart function for these patients with very few other options. Given that hyperglycemia promotes the generation of toxic metabolites, the influence of the key detoxification enzyme glyoxalase 1 (Glo1) on chronic hyperglycemia induced heart explant-derived cell (EDC) dysfunction was investigated. Methods: EDCs were cultured from wild type C57Bl/6 or Glo1 over-expressing transgenic mice 2 months after treatment with the pancreatic beta cell toxin streptozotocin or vehicle. The effects of Glo1 overexpression was evaluated using in vitro and in vivo models of myocardial ischemia. Results: Chronic hyperglycemia reduced overall culture yields and increased the reactive dicarbonyl cell burden within EDCs. These intrinsic cell changes reduced the angiogenic potential and production of pro-healing exosomes while promoting senescence and slowing proliferation. Compared to intra-myocardial injection of normoglycemic cells, chronic hyperglycemia attenuated cell-mediated improvements in myocardial function and reduced the ability of transplanted cells to promote new blood vessel and cardiomyocyte growth. In contrast, Glo1 overexpression decreased oxidative damage while restoring both cell culture yields and EDC-mediated repair of ischemic myocardium. The latter was associated with enhanced production of pro-healing extracellular vesicles by Glo1 cells without altering the pro-healing microRNA cargo within. Conclusions: Chronic hyperglycemia decreases the regenerative performance of EDCs. Overexpression of Glo1 reduces dicarbonyl stress and prevents chronic hyperglycemia-induced dysfunction by rejuvenating the production of pro-healing extracellular vesicles.

Early Discharge of Neutropenic Pediatric Oncology Patients Admitted With Fever.

BACKGROUND: Fever and neutropenia (FN) is a common complication of pediatric oncology therapy and accounts for a large number of hospital admissions. Standard therapy for FN includes hospital admission and empiric antibiotics. Strict adherence to this practice leads to prolonged hospitalizations that may be unnecessary for patients at low risk of having an underlying significant infection. PROCEDURE: Children admitted with FN could be discharged after a minimum of 48 hr with no further antibiotic therapy once they had been afebrile for 24 hr with negative blood cultures from initial presentation, regardless of their neutrophil count. We performed a retrospective review with regard to readmissions and subsequent documented infections in FN patients discharged with an ANC of ≤500 cells/mm(3) . RESULTS: There were 299 FN admissions in 188 patients who were discharged prior to achieving an ANC of ≥500 cells/mm(3) . Readmission to the hospital during the same period of neutropenia occurred in 50 cases (16.7%) with 27 infections diagnosed in 21 patients. Patients discharged with an ANC of ≤100 cells/mm(3) (odds ratio 3.7) and patients with acute lymphoblastic leukemia (odds ratio 2.6) were more likely to be readmitted for fever. All patients that developed a significant infection had an ANC of ≤100 cells/mm(3) at admission and discharge. In patients that developed a significant infection, only one required admission to the intensive care unit with no deaths. CONCLUSIONS: The practice of discharging patients with persistent neutropenia who are afebrile with negative blood cultures produces acceptable rates of readmission and subsequent infection and does not lead to increased morbidity and mortality.

The impact of patient co-morbidities on the regenerative capacity of cardiac explant-derived stem cells.

BACKGROUND: Although patient-sourced cardiac stem cells repair damaged myocardium, the extent to which medical co-morbidities influence cardiac-derived cell products is uncertain. Therefore, we investigated the influence of atherosclerotic risk factors on the regenerative performance of human cardiac explant-derived cells (EDCs). METHODS: In this study, the Long Term Stratification for survivors of acute coronary syndromes model was used to quantify the burden of cardiovascular risk factors within a group of patients with established atherosclerosis. EDCs were cultured from human atrial appendages and injected into immunodeficient mice 7 days post-left coronary ligation. Cytokine arrays and enzyme linked immunoassays were used to determine the release of cytokines by EDCs in vitro, and echocardiography was used to determine regenerative capabilities in vivo. RESULTS: EDCs sourced from patients with more cardiovascular risk factors demonstrated a negative correlation with production of pro-healing cytokines (such as stromal cell derived factor 1α) and exosomes which had negative effects on the promotion of angiogenesis and chemotaxis. Reductions in exosomes and pro-healing cytokines with accumulating medical co-morbidities were associated with increases in production of the pro-inflammatory cytokine interleukin-6 (IL-6) by EDCs. Increased patient co-morbidities were also correlated with significant attenuation in improvements of left ventricular ejection fraction. CONCLUSIONS: The regenerative performance of the earliest precursor cell population cultured from human explant tissue declines with accumulating medical co-morbidities. This effect is associated with diminished production of pro-cardiogenic cytokines and exosomes while IL-6 is markedly increased. Predictors of cardiac events demonstrated a lower capacity to support angiogenesis and repair injured myocardium in a mouse model of myocardial infarction.