Background/Aims: Acute kidney injury (AKI) during septic shock, which is one of the most common clinical syndromes in the intensive care unit (ICU), has a high mortality rate and poor prognosis, partly because of a poor understanding of the pathogenesis of renal dysfunction during septic shock. Although ischemic injury of the kidney has been reported to result from adenosine triphosphate (ATP) depletion, increasing evidence has demonstrated that AKI occurs in the absence of renal hypoperfusion and even occurs during normal or increased renal blood flow (RBF); nevertheless, whether energy metabolism disorder is involved in septic AKI and whether it changes according to renal hemodynamics have not been established. Moreover, tubular cell apoptosis, which is closely related to ATP depletion, rather than necrosis, has been shown to be the major form of cell injury during AKI. Methods: We used canine endotoxin shock models to investigate the hemodynamics, renal energy metabolism, renal oxygen metabolism, and pathological changes during septic AKI and to explore the underlying mechanisms of septic AKI. Results: The present results revealed that the nicotinamide adenine dinucleotide (NAD+) pool and the ATP/adenosine diphosphate (ADP) ratio were significantly decreased during the early phase of septic AKI, which is accompanied by a decreased renal oxygen extraction ratio (O2ER%) and decreased renal oxygen consumption (VO2). Furthermore, significant apoptosis was observed following renal dysfunction. RBF and renal oxygen delivery were not significantly altered. Conclusion: These results suggest that imbalanced energy metabolism, rather than tubular cell apoptosis, may be the initiator of renal dysfunction during septic shock.
Poly-(ADP-ribose) polymerases (PARPs), a super family of enzymes, play important roles in preserving genomic integrity, regulating transcriptions, protecting telomeres and determining cell fate. PARP overactivation leads to metabolic disorder and cell injury via depletion of energy substance. However, it is still unclear whether PARP overactivation happens during acute kidney injury (AKI) caused by endotoxic shock (ES). Here, we built a canine model of lipopolysaccharide-induced ES to explore the role of PARP during the development AKI. We also used an intravenous injection of 3-aminobenzamide (3-AB) to further explore whether PARP inhibition rescues the kidney from injury. Cell fate and energy metabolism were detected to explore the underlying mechanisms. As a result, Western blot and immunohistochemistry assays showed PARP overactivation in the very early phase of ES. Through PARP inhibition by 3-AB, we observed significant improvement of systemic hemodynamics, renal hemodynamics, renal oxygen metabolism and renal tubular cell apoptosis. These findings indicated that overactivation of PARP plays an important role in septic AKI. Inhibition of PARP overactivation may protect renal function against hemodynamic disorder, renal metabolism disturbance and renal cell apoptosis during endotoxic AKI.
In this paper, the influence of concrete strength, diameter, cover thickness, anchorage length, and stirrups ratio on the bonding performance of the HSCR rebar in concrete are experimentally investigated. A nonlinear FE model for simulating the bond performance between HSCR and concrete is established and validated, and the influencing parameters are parametrically investigated. Moreover, the applicability of the ultimate bond strength model for HSCR-concrete is comparatively discussed, and a new model is proposed and validated to give relatively accurate prediction. Based on the proposed model, the anchorage reliability analysis is conducted, the influencing parameters as well as their variation on the reliability of bond strength are discussed, and the reliable anchorage length is recommended.
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