Hibernating mitochondria, the cool key to cellular protection and transplant optimization:Mitochondrial aspects of hibernators and non-hibernators in hypothermia

Organ transplantation is a lifesaving therapy for patients suffering from end-stage organ failure. However, during the process of transplantation, organs are exposed to prolonged ischemia and subsequent reperfusion injury (I/R), which is detrimental for organ quality. Key to this I/R damage is failure of mitochondrial function resulting in loss of ATP production and the production of reactive oxygen species (ROS). The cornerstone to reduce I/R damage remains the traditional philosophy to induce a forced hypometabolic state by cooling with ice. However, this showed to be suboptimal and new preservation techniques are needed. This thesis suggests hibernation. Hibernating species are able to alternate between states of low body temperature and low oxygen levels and fast rewarming to normal temperature and oxygen levels, without tissue damage. This thesis speculates that cellular protection during hibernation appears to affect cell metabolism through mitochondrial pathways, as mitochondria fulfill an important and well known role in survival via ATP production that fuels cellular processes, but conversely also as ROS producer and apoptosis regulator in I/R. Therefore, in this project we looked into mitochondrial function and malfunction in hibernator and non-hibernator derived cells at different temperatures. With special interest in ROS formation and DNA damage. Additionally, by using an in vitro model of porcine kidney transplantation, we tried to obtain more insights into mitochondrial behavior during organ transplantation, with special focus on temperature effects and induction of a hibernation-like state using the smelling gas H2S

Quadruple junction polymer solar cells with four complementary absorber layers

A monolithic two‐terminal solution‐processed quadruple junction polymer solar cell in an n–i–p (inverted) configuration with four complementary polymer:fullerene active bulk‐heterojunction layers is presented. The subcells possess different optical bandgaps ranging from 1.90 to 1.13 eV. Optical modeling using the transfer matrix formalism enables prediction of the fraction of absorbed photons from sunlight in each subcell and determine the optimal combination of layer thicknesses. The quadruple junction cell features an open‐circuit voltage of 2.45 V and has a power conversion efficiency of 7.6%, only slightly less than the modeled value of 8.2%. The external quantum efficiency spectrum, determined with appropriate light and voltage bias conditions, exhibits in general an excellent agreement with modeled spectrum. The device performance is presently limited by bimolecular recombination, which prevents using thick photoactive layers that could absorb light more efficiently

Evaluation of a collaborative care program for patients with treatment-resistant schizophrenia:Protocol for a multiple case study

Background: Approximately one-third of all patients with schizophrenia are treatment resistant. Worldwide, undertreatment with clozapine and other effective treatment options exist for people with treatment-resistant schizophrenia (TRS). In this respect, it appears that regular health care models do not optimally fit this patient group. The Collaborative Care (CC) model has proven to be effective for patients with severe mental illness, both in primary care and in specialized mental health care facilities. The key principles of the CC model are that both patients and informal caregivers are part of the treatment team, that a structured treatment plan is put in place with planned evaluations by the team, and that the treatment approach is multidisciplinary in nature and uses evidence-based interventions. We developed a tailored CC program for patients with TRS. Objective: In this paper, we provide an overview of the research design for a potential study that seeks to gain insight into both the process of implementation and the preliminary effects of the CC program for patients with TRS. Moreover, we aim to gain insight into the experiences of professionals, patients, and informal caregivers with the program. Methods: This study will be underpinned by a multiple case study design (N=20) that uses a mixed methods approach. These case studies will focus on an Early Psychosis Intervention Team and 2 Flexible Assertive Community treatment teams in the Netherlands. Data will be collected from patient records as well as through questionnaires, individual interviews, and focus groups. Patient recruitment commenced from October 2020. Results: Recruitment of participants commenced from October 2020, with the aim of enrolling 20 patients over 2 years. Data collection will be completed by the end of 2023, and the results will be published once all data are available for reporting. Conclusions: The research design, framed within the process of developing and testing innovative interventions, is discussed in line with the aims of the study. The limitations in clinical practice and specific consequences of this study are explained. International registered Report Identifier(IRRID): DERR1-10.2196/35336

Realization of an Asymmetric Non‐Aqueous Redox Flow Battery through Molecular Design to Minimize Active Species Crossover and Decomposition

This communication presents a mechanism‐based approach to identify organic electrolytes for non‐aqueous redox flow batteries (RFBs). Symmetrical flow cell cycling of a pyridinium anolyte and a cyclopropenium catholyte resulted in extensive capacity fade due to competing decomposition of the pyridinium species. Characterization of this decomposition pathway enabled the rational design of next‐generation anolyte/catholyte pairs with dramatically enhanced cycling performance. Three factors were identified as critical for slowing capacity fade: (1) separating the anolyte–catholyte in an asymmetric flow cell using an anion exchange membrane (AEM); (2) moving from monomeric to oligomeric electrolytes to limit crossover through the AEM; and (3) removing the basic carbonyl moiety from the anolyte to slow the protonation‐induced decomposition pathway. Ultimately, these modifications led to a novel anolyte–catholyte pair that can be cycled in an AEM‐separated asymmetric RFB for 96 h with >95 % capacity retention at an open circuit voltage of 1.57 V.Applied molecular design! This study presents a mechanism‐based approach to the molecular design of electrolytes for implementation in an asymmetric non‐aqueous redox flow battery.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154972/1/chem202000749-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154972/2/chem202000749.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154972/3/chem202000749_am.pd

Cooling of Cells and Organs Confers Extensive DNA Strand Breaks Through Oxidative Stress and ATP Depletion

Cooling at 4 degrees C is routinely used to lower metabolism and preserve cell and tissue integrity in laboratory and clinical settings, including organ transplantation. However, cooling and rewarming produce cell damage, attributed primarily to a burst of reactive oxygen species (ROS) upon rewarming. While DNA represents a highly vulnerable target of ROS, it is unknown whether cooling and/or rewarming produces DNA damage. Here, we show that cooling alone suffices to produce extensive DNA damage in cultured primary cells and cell lines, including double-strand breaks (DSBs), as shown by comet assay and pulsed-field gel electrophoresis. Cooling-induced DSB formation is time- and temperature-dependent and coincides with an excess production of ROS, rather than a decrease in ATP levels. Immunohistochemistry confirmed that DNA damage activates the DNA damage response marked by the formation of nuclear foci of proteins involved in DSB repair, gamma-H2Ax, and 53BP1. Subsequent rewarming for 24 h fails to recover ATP levels and only marginally lowers DSB amounts and nuclear foci. Precluding ROS formation by dopamine and the hydroxychromanol, Sul-121, dose-dependently reduces DSBs. Finally, a standard clinical kidney transplant procedure, using cold static storage in UW preservation solution up to 24 h in porcine kidney, lowered ATP, increased ROS, and produced increasing amounts of DSBs with recruitment of 53BP1. Given that DNA repair is erroneous by nature, cooling-inflicted DNA damage may affect cell survival, proliferation, and genomic stability, significantly impacting cellular and organ function, with relevance in stem cell and transplantation procedures

The Effects of 6-Chromanol SUL-138 during Hypothermic Machine Perfusion on Porcine Deceased Donor Kidneys

Diminishing ischemia-reperfusion injury (IRI) by improving kidney preservation techniques offers great beneficial value for kidney transplant recipients. Mitochondria play an important role in the pathogenesis of IRI and are therefore interesting targets for pharmacological interventions. Hypothermic machine perfusion (HMP), as a preservation strategy, offers the possibility to provide mitochondrial–targeted therapies. This study focuses on the addition of a mitochondrial protective agent SUL—138 during HMP and assesses its effect on kidney function and injury during normothermic reperfusion. In this case, 30 min of warm ischemia was applied to porcine slaughterhouse kidneys before 24 h of non–oxygenated HMP with or without the addition of SUL—138. Functional assessment was performed by 4 h normothermic autologous blood reperfusion. No differences in renal function or perfusion parameters were found between both groups. ATP levels were lower after 30 min of warm ischemia in the SUL–138 group (n.s, p = 0.067) but restored significantly during 24 h of HMP in combination with SUL—138. Aspartate aminotransferase (ASAT) levels were significantly lower for the SUL—138 group. SUL—138 does not influence renal function in this model. Restoration of ATP levels during 24 h of HMP with the addition of SUL in combination with lower ASAT levels could be an indication of improved mitochondrial function

Inhibition of Ferroptosis Enables Safe Rewarming of HEK293 Cells following Cooling in University of Wisconsin Cold Storage Solution

The prolonged cooling of cells results in cell death, in which both apoptosis and ferroptosis have been implicated. Preservation solutions such as the University of Wisconsin Cold Storage Solution (UW) encompass approaches addressing both. The use of UW improves survival and thus extends preservation limits, yet it remains unclear how exactly organ preservation solutions exert their cold protection. Thus, we explored cooling effects on lipid peroxidation and adenosine triphosphate (ATP) levels and the actions of blockers of apoptosis and ferroptosis, and of compounds enhancing mitochondrial function. Cooling and rewarming experiments were performed in a cellular transplantation model using Human Embryonic Kidney (HEK) 293 cells. Cell viability was assessed by neutral red assay. Lipid peroxidation levels were measured by Western blot against 4-Hydroxy-Nonenal (4HNE) and the determination of Malondialdehyde (MDA). ATP was measured by luciferase assay. Cooling beyond 5 h in Dulbecco's Modified Eagle Medium (DMEM) induced complete cell death in HEK293, whereas cooling in UW preserved ~60% of the cells, with a gradual decline afterwards. Cooling-induced cell death was not precluded by inhibiting apoptosis. In contrast, the blocking of ferroptosis by Ferrostatin-1 or maintaining of mitochondrial function by the 6-chromanol SUL150 completely inhibited cell death both in DMEM- and UW-cooled cells. Cooling for 24 h in UW followed by rewarming for 15 min induced a ~50% increase in MDA, while concomitantly lowering ATP by &gt;90%. Treatment with SUL150 of cooled and rewarmed HEK293 effectively precluded the increase in MDA and preserved normal ATP in both DMEM- and UW-cooled cells. Likewise, treatment with Ferrostatin-1 blocked the MDA increase and preserved the ATP of rewarmed UW HEK293 cells. Cooling-induced HEK293 cell death from hypothermia and/or rewarming was caused by ferroptosis rather than apoptosis. UW slowed down ferroptosis during hypothermia, but lipid peroxidation and ATP depletion rapidly ensued upon rewarming, ultimately resulting in complete cell death. Treatment throughout UW cooling with small-molecule Ferrostatin-1 or the 6-chromanol SUL150 effectively prevented ferroptosis, maintained ATP, and limited lipid peroxidation in UW-cooled cells. Counteracting ferroptosis during cooling in UW-based preservation solutions may provide a simple method to improve graft survival following cold static cooling.</p

ZILVERPASS Study: ZILVER PTX Stent versus Prosthetic Above-the-Knee Bypass Surgery in Femoropopliteal Lesions, 5-year Results.

PURPOSE To report the 60-month safety and effectiveness results of a multicenter, prospective, randomized controlled trial comparing the ZILVER PTX paclitaxel-eluting stent to prosthetic above-the-knee bypass for the treatment of symptomatic TransAtlantic Inter-Society Consensus (TASC) C and D femoropopliteal lesions. MATERIALS AND METHODS Patients were enrolled between October 2013 and July 2017. One of the secondary outcomes was primary patency at 60 months, defined as no evidence of binary restenosis or occlusion within the target lesion or bypass graft based on a duplex ultrasound peak systolic velocity ratio < 2.4 and no clinically-driven target lesion revascularization (TLR) in endovascular cases or reintervention to restore flow in the bypass at 60 months. Survival rates after 5 years were also analyzed. RESULTS 220 patients (mean age 68.6 ± 10.5 years; 159 men) were included and randomized to ZILVER PTX (n = 113, 51.40%) or BYPASS group (n = 107, 48.60%). The 60-month primary patency rate was 49.3% for the ZILVER PTX group versus 40.7% for the bypass group (p = 0.6915). Freedom from TLR was 63.8% for the ZILVER PTX group versus 52.8% for the bypass group (p = 0.2637). At 5 years, no significant difference in survival rate could be seen between the ZILVER PTX and the bypass group (69.1% vs. 71% respectively, p = 0.5503). CONCLUSION Even at 5 years, non-inferior safety and effectiveness results of the ZILVER PTX could be seen. These findings confirmed that the use of ZILVER PTX stents can be considered as a valid alternative for bypass surgery when treating long and complex femoropopliteal lesions

Hydrogen sulphide-induced hypometabolism in human-sized porcine kidneys

Background Since the start of organ transplantation, hypothermia-forced hypometabolism has been the cornerstone in organ preservation. Cold preservation showed to protect against ischemia, although post-transplant injury still occurs and further improvement in preservation techniques is needed. We hypothesize that hydrogen sulphide can be used as such a new preservation method, by inducing a reversible hypometabolic state in human sized kidneys during normothermic machine perfusion. Methods Porcine kidneys were connected to an ex-vivo isolated, oxygen supplemented, normothermic blood perfusion set-up. Experimental kidneys (n = 5) received a 85mg NaHS infusion of 100 ppm and were compared to controls (n = 5). As a reflection of the cellular metabolism, oxygen consumption, mitochondrial activity and tissue ATP levels were measured. Kidney function was assessed by creatinine clearance and fractional excretion of sodium. To rule out potential structural and functional deterioration, kidneys were studied for biochemical markers and histology. Results Hydrogen sulphide strongly decreased oxygen consumption by 61%, which was associated with a marked decrease in mitochondrial activity/function, without directly affecting ATP levels. Renal biological markers, renal function and histology did not change after hydrogen sulphide treatment. Conclusion In conclusion, we showed that hydrogen sulphide can induce a controllable hypometabolic state in a human sized organ, without damaging the organ itself and could thereby be a promising therapeutic alternative for cold preservation under normothermic conditions in renal transplantation