Mitochondrial-derived reactive oxygen species have been deemed an important contributor in sepsis pathogenesis. We investigated whether two mitochondria-targeted antioxidants (mtAOX; SkQ1 and MitoTEMPO) improved long-term outcome, lessened inflammation, and improved organ homeostasis in polymicrobial murine sepsis. 3-month-old female CD-1 mice (n = 90) underwent cecal ligation and puncture (CLP) and received SkQ1 (5 nmol/kg), MitoTEMPO (50 nmol/kg), or vehicle 5 times post-CLP. Separately, 52 SkQ1-treated CLP mice were sacrificed at 24 h and 48 h for additional endpoints. Neither MitoTEMPO nor SkQ1 exerted any protracted survival benefit. Conversely, SkQ1 exacerbated 28-day mortality by 29%. CLP induced release of 10 circulating cytokines, increased urea, ALT, and LDH, and decreased glucose but irrespectively of treatment. Similar occurred for CLP-induced lymphopenia/neutrophilia and the NO blood release. At 48 h post-CLP, dying mice had approximately 100-fold more CFUs in the spleen than survivors, but this was not SkQ1 related. At 48 h, macrophage and granulocyte counts increased in the peritoneal lavage but irrespectively of SkQ1. Similarly, hepatic mitophagy was not altered by SkQ1 at 24 h. The absence of survival benefit of mtAOX may be due to the extended treatment and/or a relatively moderate-risk-of-death CLP cohort. Long-term effect of mtAOX in abdominal sepsis appears different to sepsis/inflammation models arising from other body compartments.

Purpose: Pancreatic cancer is typically diagnosed in a late stage with limited therapeutic options. For those patients, ultrasound-guided high-intensity focused ultrasound (US-HIFU) can improve local control and alleviate pain. However, MRI-guided HIFU (MR-HIFU) has not yet been studied extensively in this context. To facilitate related research and accelerate clinical translation, we report a workflow for the in vivo HIFU ablation of the porcine pancreas under MRI guidance. Materials and methods: The pancreases of five healthy German landrace pigs (35-58 kg) were sonicated using a clinical MR-HIFU system. Acoustic access to the pancreas was supported by a specialized diet and a hydrogel compression device for bowel displacement. Organ motion was suspended using periods of apnea. The size of the resulting thermal lesions was assessed using the thermal thresholdand dose profiles, non-perfused volume, and gross examination. The effect of the compression device on beam path length was assessed using MRI imaging. Results: Eight of ten treatments resulted in clearly visible damage in the target tissue upon gross examination. Five treatments resulted in coagulative necrosis. Good agreement between the four metrics for lesion size and a clear correlation between the delivered energy dose and the resulting lesion size were found. The compression device notably shortened the intra-abdominal beam path. Conclusions: We demonstrated a workflow for HIFU treatment of the porcine pancreas in-vivo under MRI-guidance. This development bears significance for the development of MR-guided HIFU interventions on the pancreas as the pig is the preferred animal model for the translation of pre-clinical research into clinical application.

Purpose: This article will report results from the in-vivo application of a previously published model-predictive control algorithm for MR-HIFU hyperthermia. The purpose of the investigation was to test the controller's in-vivo performance and behavior in the presence of heterogeneous perfusion. Materials and methods: Hyperthermia at 42 C was induced and maintained for up to 30 min in a circular section of a thermometry slice in the biceps femoris of German landrace pigs (n¼5) using a commercial MR-HIFU system and a recently developed MPC algorithm. The heating power allocation was correlated with heat sink maps and contrast-enhanced MRI images. The temporal change in perfusion was estimated based on the power required to maintain hyperthermia. Results: The controller performed well throughout the treatments with an absolute average tracking error of 0.27 ± 0.15 C and an average difference of 1.25 ± 0.22 C between T 10 and T 90 : The MPC algorithm allocates additional heating power to sub-volumes with elevated heat sink effects, which are colocalized with blood vessels visible on contrast-enhanced MRI. The perfusion appeared to have increased by at least a factor of $1.86 on average. Conclusions: The MPC controller generates temperature distributions with a narrow spectrum of voxel temperatures inside the target ROI despite the presence of spatiotemporally heterogeneous perfusion due to the rapid thermometry feedback available with MR-HIFU and the flexible allocation of heating power. The visualization of spatiotemporally heterogeneous perfusion presents new research opportunities for the investigation of stimulated perfusion in hypoxic tumor regions.

In polytrauma patients, the impact of splenectomy is equivocal, ranging from negative to protective. We investigated the impact of splenectomy on immune responses in the 1st-hit polytrauma alone and on survival in the post-traumatic sepsis (2nd hit). Female BALB/c mice underwent polytrauma (1st hit) consisting of either a) TH: femur fracture, hemorrhagic shock or b) TSH: splenectomy, femur fracture, hemorrhagic shock. Additionally, the polytrauma hit was followed by cecal ligation and puncture (CLP) 48 h later and compared to CLP alone. Splenectomy improved the 28-day survival in secondary sepsis to 92% (from 62%), while TH lowered it to 46% (p < 0.05). The improved survival was concurrent with lower release of inflammatory cytokines (IL-6, CXCL-1, MCP-1) and increase of C5a post-CLP. In the polytrauma hit alone, TSH induced stronger neutrophilia (1.9 fold) and lymphocytosis (1.7 fold) when compared to TH mice. Moreover, TSH resulted in a 41% rise of regulatory T-cells and reduced the median fluorescence intensity of MHC-2 on monocytes by 55% within 48 h (p < 0.05). Conversely, leukocyte phagocytic capacity was significantly increased by 4-fold after TSH despite a similar M1/M2 macrophage profile in both groups. Summarizing, splenectomy provoked both immuno-suppressive and immuno-stimulatory responses but was life-saving in secondary sepsis. Additionally, the polytrauma components in 2-hit models should be tested for their effects on outcome; the presumed end-effect of the 1st hit solely based on the common immuno-inflammatory parameters could be misleading.