Background:It is a major clinical challenge to ensure the long-term function of transplanted kidneys. Specifically, the injury associated with cold storage of kidneys compromises the long-term function of the grafts after transplantation. Therefore, the molecular mechanisms underlying cold-storage–related kidney injury are attractive therapeutic targets to prevent injury and improve long-term graft function. Previously, we found that constitutive proteasome function was compromised in rat kidneys after cold storage followed by transplantation. Here, we evaluated the role of the immunoproteasome (iproteasome), a proteasome variant, during cold storage (CS) followed by transplantation. Methods:Established in vivo rat kidney transplant model with or without CS containing vehicle or iproteasome inhibitor (ONX 0914) was used in this study. Theiproteasome function was performed using rat kidney homogenates and fluorescent-based peptide substrate specific to β5i subunit. Western blotting and quantitative RT-PCR were used to assess the subunit expression/level of theiproteasome (β5i) subunit. Results:We demonstrated a decrease in the abundance of the β5i subunit of theiproteasome in kidneys during CS, but β5i levels increased in kidneys after CS and transplant. Despite the increase in β5i levels and its peptidase activity within kidneys, inhibiting β5i during CS did not improve graft function after transplantation. Summary:These results suggest that the pharmacological inhibition of immunoproteasome function during CS does not improve graft function or outcome. In light of these findings, future studies targeting immunoproteasomes during both CS and transplantation may define the role of immunoproteasomes on short- and long-term kidney transplant outcomes. 
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                            Copper deficiency is an independent risk factor for mortality in patients with advanced liver disease
                        
                    
    
            Background and Aim:Copper is an essential trace metal serving as a cofactor in innate immunity, metabolism, and iron transport. We hypothesize that copper deficiency may influence survival in patients with cirrhosis through these pathways. Methods:We performed a retrospective cohort study involving 183 consecutive patients with cirrhosis or portal hypertension. Copper from blood and liver tissues was measured using inductively coupled plasma mass spectrometry. Polar metabolites were measured using nuclear magnetic resonance spectroscopy. Copper deficiency was defined by serum or plasma copper below 80 µg/dL for women or 70 µg/dL for men. Results:The prevalence of copper deficiency was 17% (N=31). Copper deficiency was associated with younger age, race, zinc and selenium deficiency, and higher infection rates (42% vs. 20%,p=0.01). Serum copper correlated positively with albumin, ceruloplasmin, hepatic copper, and negatively with IL-1β. Levels of polar metabolites involved in amino acids catabolism, mitochondrial transport of fatty acids, and gut microbial metabolism differed significantly according to copper deficiency status. During a median follow-up of 396 days, mortality was 22.6% in patients with copper deficiency compared with 10.5% in patients without. Liver transplantation rates were similar (32% vs. 30%). Cause-specific competing risk analysis showed that copper deficiency was associated with a significantly higher risk of death before transplantation after adjusting for age, sex, MELD-Na, and Karnofsky score (HR: 3.40, 95% CI, 1.18–9.82,p=0.023). Conclusions:In advanced cirrhosis, copper deficiency is relatively common and is associated with an increased infection risk, a distinctive metabolic profile, and an increased risk of death before transplantation. 
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                            - Award ID(s):
- 2018388
- PAR ID:
- 10482190
- Publisher / Repository:
- Wolters Kluwer Health, Inc.
- Date Published:
- Journal Name:
- Hepatology Communications
- Volume:
- 7
- Issue:
- 3
- ISSN:
- 2471-254X
- Page Range / eLocation ID:
- e0076 to e0076
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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