The failing human heart is characterized by metabolic abnormalities, but these defects remains incompletely understood. In animal models of heart failure there is a switch from a predominance of ...fatty acid utilization to the more oxygen-sparing carbohydrate metabolism. Recent studies have reported decreases in myocardial lipid content, but the inclusion of diabetic and nondiabetic patients obscures the distinction of adaptations to metabolic derangements from adaptations to heart failure per se.
We performed both unbiased and targeted myocardial lipid surveys using liquid chromatography-mass spectroscopy in nondiabetic, lean, predominantly nonischemic, advanced heart failure patients at the time of heart transplantation or left ventricular assist device implantation. We identified significantly decreased concentrations of the majority of myocardial lipid intermediates, including long-chain acylcarnitines, the primary subset of energetic lipid substrate for mitochondrial fatty acid oxidation. We report for the first time significantly reduced levels of intermediate and anaplerotic acyl-coenzyme A (CoA) species incorporated into the Krebs cycle, whereas the myocardial concentration of acetyl-CoA was significantly increased in end-stage heart failure. In contrast, we observed an increased abundance of ketogenic β-hydroxybutyryl-CoA, in association with increased myocardial utilization of β-hydroxybutyrate. We observed a significant increase in the expression of the gene encoding succinyl-CoA:3-oxoacid-CoA transferase, the rate-limiting enzyme for myocardial oxidation of β-hydroxybutyrate and acetoacetate.
These findings indicate increased ketone utilization in the severely failing human heart independent of diabetes mellitus, and they support the role of ketone bodies as an alternative fuel and myocardial ketone oxidation as a key metabolic adaptation in the failing human heart.
Background. Despite the high prevalence of patient-reported antibiotic allergy (so-called antibiotic allergy labels AALs) and their impact on antibiotic prescribing, incorporation of antibiotic ...allergy testing (AAT) into antimicrobial stewardship (AMS) programs (AAT-AMS) is not widespread. We aimed to evaluate the impact of an AAT-AMS program on AAL prevalence, antibiotic usage, and appropriateness of prescribing. Methods. AAT-AMS was implemented at two large Australian hospitals during a 14-month period beginning May 2015. Baseline demographics, AAL history, age-adjusted Charlson comorbidity index, infection history, and antibiotic usage for 12 months prior to testing (pre–AAT-AMS) and 3 months following testing (post–AAT-AMS) were recorded for each participant. Study outcomes included the proportion of patients who were "de-labeled" of their AAL, spectrum of antibiotic courses pre– and post–AAT-AMS, and antibiotic appropriateness (using standard definitions). Results. From the 118 antibiotic allergy—tested patients, 226 AALs were reported (mean, 1.91/patient), with 53.6% involving 1 or more penicillin class drug. AAT-AMS allowed AAL de-labeling in 98 (83%) patients–56% (55/98) with all AALs removed. Post– AAT, prescribing of narrow-spectrum penicillins was more likely (adjusted odds ratio aOR, 2.81, 95% confidence interval CI, 1.45–5.42), as was narrow-spectrum β-lactams (aOR, 3.54; 95% CI, 1.98–6.33), and appropriate antibiotics (aOR, 12.27; 95% CI, 5.00–30.09); and less likely for restricted antibiotics (aOR, 0.16; 95% CI, 09–.29), after adjusting for indication, Charlson comorbidity index, and care setting. Conclusions. An integrated AAT-AMS program was effective in both de-labeling of AALs and promotion of improved antibiotic usage and appropriateness, supporting the routine incorporation of AAT into AMS programs.
Macrophage activation/polarization to distinct functional states is critically supported by metabolic shifts. How polarizing signals coordinate metabolic and functional reprogramming, and the ...potential implications for control of macrophage activation, remains poorly understood. Here we show that IL-4 signaling co-opts the Akt-mTORC1 pathway to regulate Acly, a key enzyme in Ac-CoA synthesis, leading to increased histone acetylation and M2 gene induction. Only a subset of M2 genes is controlled in this way, including those regulating cellular proliferation and chemokine production. Moreover, metabolic signals impinge on the Akt-mTORC1 axis for such control of M2 activation. We propose that Akt-mTORC1 signaling calibrates metabolic state to energetically demanding aspects of M2 activation, which may define a new role for metabolism in supporting macrophage activation.
The antitumor agent lonidamine (LND; 1-(2,4-dichlorobenzyl)-1H-indazole-3-carboxylic acid) is known to interfere with energy-yielding processes in cancer cells. However, the effect of LND on central ...energy metabolism has never been fully characterized. In this study, we report that a significant amount of succinate is accumulated in LND-treated cells. LND inhibits the formation of fumarate and malate and suppresses succinate-induced respiration of isolated mitochondria. Utilizing biochemical assays, we determined that LND inhibits the succinate-ubiquinone reductase activity of respiratory complex II without fully blocking succinate dehydrogenase activity. LND also induces cellular reactive oxygen species through complex II, which reduced the viability of the DB-1 melanoma cell line. The ability of LND to promote cell death was potentiated by its suppression of the pentose phosphate pathway, which resulted in inhibition of NADPH and glutathione generation. Using stable isotope tracers in combination with isotopologue analysis, we showed that LND increased glutaminolysis but decreased reductive carboxylation of glutamine-derived α-ketoglutarate. Our findings on the previously uncharacterized effects of LND may provide potential combinational therapeutic approaches for targeting cancer metabolism.
Histone acetylation plays important roles in gene regulation, DNA replication, and the response to DNA damage, and it is frequently deregulated in tumors. We postulated that tumor cell histone ...acetylation levels are determined in part by changes in acetyl coenzyme A (acetyl-CoA) availability mediated by oncogenic metabolic reprogramming. Here, we demonstrate that acetyl-CoA is dynamically regulated by glucose availability in cancer cells and that the ratio of acetyl-CoA:coenzyme A within the nucleus modulates global histone acetylation levels. In vivo, expression of oncogenic Kras or Akt stimulates histone acetylation changes that precede tumor development. Furthermore, we show that Akt’s effects on histone acetylation are mediated through the metabolic enzyme ATP-citrate lyase and that pAkt(Ser473) levels correlate significantly with histone acetylation marks in human gliomas and prostate tumors. The data implicate acetyl-CoA metabolism as a key determinant of histone acetylation levels in cancer cells.
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•Acetyl-CoA:CoA ratio is glucose sensitive and regulates histone acetylation levels•Oncogenic AKT expression promotes elevated histone acetylation in vitro and in vivo•ACLY phosphorylation by AKT enables sustained histone acetylation in low glucose•Histone acetylation and pAKT(Ser473) levels correlate significantly in human tumors
Lee et al. show that metabolic reprogramming induced by an oncogene affects histone acetylation. Under conditions of low glucose, Akt activates the acetyl-CoA-generating enzyme ATP-citrate lyase, leading to alterations in histone acetylation marks in tumors. In vivo, oncogenic Kras or Akt expression stimulates histone acetylation changes preceding tumor development.
Replication stress induced by nucleotide deficiency plays an important role in cancer initiation. Replication stress in primary cells typically activates the cellular senescence tumor-suppression ...mechanism. Senescence bypass correlates with development of cancer, a disease characterized by metabolic reprogramming. However, the role of metabolic reprogramming in the cellular response to replication stress has been little explored. Here, we report that ataxia telangiectasia mutated (ATM) plays a central role in regulating the cellular response to replication stress by shifting cellular metabolism. ATM inactivation bypasses senescence induced by replication stress triggered by nucleotide deficiency. This was due to restoration of deoxyribonucleotide triphosphate (dNTP) levels through both upregulation of the pentose phosphate pathway via increased glucose-6-phosphate dehydrogenase (G6PD) activity and enhanced glucose and glutamine consumption. These phenotypes were mediated by a coordinated suppression of p53 and upregulation of c-MYC downstream of ATM inactivation. Our data indicate that ATM status couples replication stress and metabolic reprogramming during senescence.
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•ATM knockdown rescues dNTP levels to bypass replication-stress-induced senescence•ATM knockdown enhances glucose and glutamine consumption for dNTP biosynthesis•Rescue of dNTP levels correlates with an increase in G6PD activity by ATM knockdown•ATM knockdown coordinately suppresses p53 and upregulates c-MYC to shift metabolism
Replication stress and metabolic reprogramming are hallmarks of cancer. Aird et al. demonstrate that ATM couples replication stress and metabolic reprogramming during senescence. ATM thus inhibits the cancer-associated metabolic program to promote senescence in response to replication stress.
To evaluate the use of a temporary calcaneotibial screw (CTS) to immobilize medial or lateral tarsocrural joint instability (TCI) in dogs.
Retrospective study.
Twelve dogs (including five active ...working farm dogs) with TCI.
Medical records (January 2015-June 2023) were retrospectively reviewed for cases of TCI managed surgically including temporary joint immobilization using a CTS and external coaptation. Clinical data consisted of medical records and an online survey completed by the owner.
Surgical techniques to address TCI included primary ligamentous repair, synthetic ligament reconstruction, or malleolar fracture repair. Immobilization with a CTS was employed for 6-8 weeks postoperatively. The online survey was completed for 10 dogs. All dogs exhibited good-to-excellent functional outcomes at the follow-up (median, 31 months; range, 4-66). All working farm dogs (5) were able to return to normal or substantial levels of their work. Four distinct complications were reported in three dogs including one CTS breakage and three bandage-related soft-tissue injuries.
This retrospective study represents the first report of employing a temporary CTS for TCI in dogs.
A temporary CTS was effective in immobilizing the tarsocrural joint for dogs with TCI and the postoperative complication rate in this study was relatively low. A CTS screw and external coaptation is a viable alternative to previously reported methods of tarsocrural joint stabilization.
Allogeneic hematopoietic stem cell transplantation (HSCT) is used as a therapeutic approach for primary immunodeficiencies (PIDs). The best outcomes have been achieved with HLA-matched donors, but ...when a matched donor is not available, a haploidentical or mismatched unrelated donor (mMUD) can be useful. Various strategies are used to mitigate the risk of graft-versus-host disease (GvHD) and rejection associated with such transplants.
We sought to evaluate the outcomes of haploidentical or mMUD HSCT after depleting GvHD-causing T-cell receptor (TCR) αβ CD3+ cells from the graft.
CD3+TCRαβ+/CD19+ depleted grafts were given in conditioned (except 3) children with PIDs. Treosulfan (busulfan in 1 patient), fludarabine, thiotepa, and anti-thymocyte globulin or alemtuzumab conditioning were used in 77% of cases, and all but 4 received GvHD prophylaxis.
Twenty-five patients with 12 types of PIDs received 26 HSCTs. Three underwent transplantation for refractory GvHD that developed after the first cord transplantation. At a median follow-up of 20.8 months (range, 5 month-3.3 years), 21 of 25 patients survived and were cured of underlying immunodeficiency. Overall and event-free survival at 3 years were 83.9% and 80.4%, respectively. Cumulative incidence of grade II to IV acute GvHD was 22% ± 8.7%. No case of visceral or chronic GvHD was seen. Cumulative incidences of graft failure, cytomegalovirus, and/or adenoviral infections and transplant-related mortality at 1 year were 4.2% ± 4.1%, 58.8% ± 9.8%, and 16.1% ± 7.4%, respectively. Patients undergoing transplantation with systemic viral infections had poor survival in comparison with those with absent or resolved infections (33.3% vs 100%).
CD3+TCRαβ+ and CD19+ cell–depleted haploidentical or mMUD HSCT is a practical and viable alternative for children with a range of PIDs.
We present a theoretical study of intersystem crossing (ISC) in acrolein and ketene with the Ehrenfest method that can describe a superposition of singlet and triplet states. Our simulations ...illustrate a new mechanistic effect of ISC, namely, that a superposition of singlets and triplets yields nonadiabatic dynamics characteristic of that superposition rather than the constituent state potential energy surfaces. This effect is particularly significant in ketene, where mixing of singlet and triplet states along the approach to a singlet/singlet conical intersection occurs, with the spin–orbit coupling (SOC) remaining small throughout. In both cases, the effects require many recrossings of the singlet/triplet state crossing seam, consistent with the textbook treatment of ISC.
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