Enhanced fatty acid oxidation through metformin and baicalin as therapy for COVID-19 and associated inflammatory states in lung and kidney.

Progressive respiratory failure is the primary cause of death in the coronavirus disease 2019 (COVID-19) pandemic. It is the final outcome of the acute respiratory distress syndrome (ARDS), characterized by an initial exacerbated inflammatory response, metabolic derangement and ultimate tissue scarring. A positive balance of cellular energy may result crucial for the recovery of clinical COVID-19. Hence, we asked if two key pathways involved in cellular energy generation, AMP-activated protein kinase (AMPK)/acetyl-CoA carboxylase (ACC) signaling and fatty acid oxidation (FAO) could be beneficial. We tested the drugs metformin (AMPK activator) and baicalin (CPT1A activator) in different experimental models mimicking COVID-19 associated inflammation in lung and kidney. We also studied two different cohorts of COVID-19 patients that had been previously treated with metformin. These drugs ameliorated lung damage in an ARDS animal model, while activation of AMPK/ACC signaling increased mitochondrial function and decreased TGF-ß-induced fibrosis, apoptosis and inflammation markers in lung epithelial cells. Similar results were observed with two indole derivatives, IND6 and IND8 with AMPK activating capacity. Consistently, a reduced time of hospitalization and need of intensive care was observed in COVID-19 patients previously exposed to metformin. Baicalin also mitigated the activation of pro-inflammatory bone marrow-derived macrophages (BMDMs) and reduced kidney fibrosis in two animal models of kidney injury, another key target of COVID-19. In human epithelial lung and kidney cells, both drugs improved mitochondrial function and prevented TGF-ß-induced renal epithelial cell dedifferentiation. Our results support that favoring cellular energy production through enhanced FAO may prove useful in the prevention of COVID-19-induced lung and renal damage.

Reciprocal regulation between the molecular clock and kidney injury.

Tubulointerstitial fibrosis is the common pathological substrate for many etiologies leading to chronic kidney disease. Although perturbations in the circadian rhythm have been associated with renal disease, the role of the molecular clock in the pathogenesis of fibrosis remains incompletely understood. We investigated the relationship between the molecular clock and renal damage in experimental models of injury and fibrosis (unilateral ureteral obstruction, folic acid, and adenine nephrotoxicity), using genetically modified mice with selective deficiencies of the clock components Bmal1, Clock, and Cry We found that the molecular clock pathway was enriched in damaged tubular epithelial cells with marked metabolic alterations. In human tubular epithelial cells, TGFß significantly altered the expression of clock components. Although Clock played a role in the macrophage-mediated inflammatory response, the combined absence of Cry1 and Cry2 was critical for the recruitment of neutrophils, correlating with a worsening of fibrosis and with a major shift in the expression of metabolism-related genes. These results support that renal damage disrupts the kidney peripheral molecular clock, which in turn promotes metabolic derangement linked to inflammatory and fibrotic responses.

De Novo Malignancy After Liver Transplantation: Risk Assessment, Prevention, and Management-Guidelines From the ILTS-SETH Consensus Conference.

De novo malignancies (DNMs) following liver transplantation (LT) have been reported as 1 of the major causes of late mortality, being the most common cause of death in the second decade after LT. The overall incidence of DNMs is reported to be in the range of 3.1% to 14.4%, and the incidence is 2- to 3-fold higher in transplant recipients than in age- and sex-matched healthy controls. Long-term immunosuppressive therapy, which is the key in maintaining host tolerance and achieving good long-term outcomes, is known to contribute to a higher risk of DNMs. However, the incidence and type of DNM also depends on different risk factors, including patient demographics, cause of the underlying chronic liver disease, behavior (smoking and alcohol abuse), and pre-existing premalignant conditions. The estimated standardized incidence ratio for different DNMs is also variable. The International Liver Transplantation Society-Spanish Society of Liver Transplantation Consensus Conference working group on DNM has summarized and discussed the current available literature on epidemiology, risk factors, management, and survival after DNMs. Recommendations for screening and surveillance for specific tumors, as well as immunosuppression and cancer-specific management in patients with DNM, are summarized.

Renal tubule Cpt1a overexpression protects from kidney fibrosis by restoring mitochondrial homeostasis.

Chronic kidney disease (CKD) remains a major epidemiological, clinical, and biomedical challenge. During CKD, renal tubular epithelial cells (TECs) present a persistent inflammatory and profibrotic response. Fatty acid oxidation (FAO), the main source of energy for TECs, is reduced in kidney fibrosis and contributes to its pathogenesis. To determine whether gain of function in FAO (FAO-GOF) could protect from fibrosis, we generated a conditional transgenic mouse model with overexpression of the fatty acid shuttling enzyme carnitine palmitoyl-transferase 1A (CPT1A) in TECs. Cpt1a-knockin (CPT1A-KI) mice subjected to 3 models of renal fibrosis (unilateral ureteral obstruction, folic acid nephropathy [FAN], and adenine-induced nephrotoxicity) exhibited decreased expression of fibrotic markers, a blunted proinflammatory response, and reduced epithelial cell damage and macrophage influx. Protection from fibrosis was also observed when Cpt1a overexpression was induced after FAN. FAO-GOF restored oxidative metabolism and mitochondrial number and enhanced bioenergetics, increasing palmitate oxidation and ATP levels, changes that were also recapitulated in TECs exposed to profibrotic stimuli. Studies in patients showed decreased CPT1 levels and increased accumulation of short- and middle-chain acylcarnitines, reflecting impaired FAO in human CKD. We propose that strategies based on FAO-GOF may constitute powerful alternatives to combat fibrosis inherent to CKD.

MiR-9-5p protects from kidney fibrosis by metabolic reprogramming.

MicroRNAs (miRNAs) regulate gene expression posttranscriptionally and control biological processes (BPs), including fibrogenesis. Kidney fibrosis remains a clinical challenge and miRNAs may represent a valid therapeutic avenue. We show that miR-9-5p protected from renal fibrosis in the mouse model of unilateral ureteral obstruction (UUO). This was reflected in reduced expression of pro-fibrotic markers, decreased number of infiltrating monocytes/macrophages, and diminished tubular epithelial cell injury and transforming growth factor-beta 1 (TGF-ß1)-dependent de-differentiation in human kidney proximal tubular (HKC-8) cells. RNA-sequencing (RNA-Seq) studies in the UUO model revealed that treatment with miR-9-5p prevented the downregulation of genes related to key metabolic pathways, including mitochondrial function, oxidative phosphorylation (OXPHOS), fatty acid oxidation (FAO), and glycolysis. Studies in human tubular epithelial cells demonstrated that miR-9-5p impeded TGF-ß1-induced bioenergetics derangement. The expression of the FAO-related axis peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α)-peroxisome proliferator-activated receptor alpha (PPARα) was reduced by UUO, although preserved by the administration of miR-9-5p. We found that in mice null for the mitochondrial master regulator PGC-1α, miR-9-5p was unable to promote a protective effect in the UUO model. We propose that miR-9-5p elicits a protective response to chronic kidney injury and renal fibrosis by inducing reprogramming of the metabolic derangement and mitochondrial dysfunction affecting tubular epithelial cells.

MicroRNA 7 Impairs Insulin Signaling and Regulates Aß Levels through Posttranscriptional Regulation of the Insulin Receptor Substrate 2, Insulin Receptor, Insulin-Degrading Enzyme, and Liver X Receptor Pathway.

Brain insulin resistance is a key pathological feature contributing to obesity, diabetes, and neurodegenerative disorders, including Alzheimer's disease (AD). Besides the classic transcriptional mechanism mediated by hormones, posttranscriptional regulation has recently been shown to regulate a number of signaling pathways that could lead to metabolic diseases. Here, we show that microRNA 7 (miR-7), an abundant microRNA in the brain, targets insulin receptor (INSR), insulin receptor substrate 2 (IRS-2), and insulin-degrading enzyme (IDE), key regulators of insulin homeostatic functions in the central nervous system (CNS) and the pathology of AD. In this study, we found that insulin and liver X receptor (LXR) activators promote the expression of the intronic miR-7-1 in vitro and in vivo, along with its host heterogeneous nuclear ribonucleoprotein K (HNRNPK) gene, encoding an RNA binding protein (RBP) that is involved in insulin action at the posttranscriptional level. Our data show that miR-7 expression is altered in the brains of diet-induced obese mice. Moreover, we found that the levels of miR-7 are also elevated in brains of AD patients; this inversely correlates with the expression of its target genes IRS-2 and IDE. Furthermore, overexpression of miR-7 increased the levels of extracellular Aß in neuronal cells and impaired the clearance of extracellular Aß by microglial cells. Taken together, these results represent a novel branch of insulin action through the HNRNPK-miR-7 axis and highlight the possible implication of these posttranscriptional regulators in a range of diseases underlying metabolic dysregulation in the brain, from diabetes to Alzheimer's disease.

Impact of tacrolimus and mycophenolate mofetil regimen vs. a conventional therapy with steroids on cardiovascular risk in liver transplant patients.

The aim of this study was to evaluate the impact of a steroid-free regimen with tacrolimus and mycophenolate mofetil (modified therapy) vs. a standard regimen of tacrolimus and steroids on the cardiovascular risk score of liver transplant recipients. Patients who received a liver transplant were randomized to a modified therapy (n = 58) or a standard regimen (n = 59). Both groups were balanced at baseline, except for a higher prevalence of diabetes mellitus (DM) (p < 0.01) and a higher serum creatinine concentration (p < 0.05) in the modified therapy group. After 12 months, the prevalence of new-onset DM, arterial hypertension, hypercholesterolemia, hypertriglyceridemia, and changes in cardiovascular risk factors was similar in both groups. The increase in serum creatinine (mg/dL) compared to baseline at one yr post-transplantation was numerically lower in the modified therapy group (0.22 ± 0.42) than in the standard regimen group (0.41 ± 0.67) (p = 0.068). Although estimated cardiovascular risk score did not vary significantly compared to baseline in either group, there was a slight reduction in the modified regimen (-0.27 ± 2.87) vs. a mild increase (0.17 ± 2.94) in the standard regimen (p = 0.566). In conclusion, a steroid-free regimen with tacrolimus and mycophenolate mofetil was associated with a trend toward better preservation of kidney function and reduction of cardiovascular risk score.

Radioembolization of hepatocellular carcinoma activates liver regeneration, induces inflammation and endothelial stress and activates coagulation.

BACKGROUND & AIMS: Radioembolization may rarely induce liver disease resulting in a syndrome that is similar to veno-occlusive disease complicating bone marrow transplantation where inflammation, endothelial cell activation and thrombosis are likely involved. We hypothesized that similar mechanisms could be implicated in radioembolization-induced liver disease (REILD). Moreover, lobar radioembolization may induce hypertrophy of the non-treated hemiliver most probably by inducing liver regeneration. METHODS: In patients with hepatocellular carcinoma, we prospectively studied serum levels of markers of liver regeneration, oxidative stress, pro-inflammatory pathways, endothelial activation and coagulation parameters over 2 months after radioembolization. RESULTS: Although REILD did not occur among 14 treated patients, a decrease in effective liver blood flow was observed. Radioembolization was followed by a persistent increase in pro-inflammatory (interleukin 6 and 8) and oxidative stress (malondyaldehide) markers, an induction of endothelial injury markers (vW factor and PAI-1) and an activation of the coagulation cascade (factor VIII, PAI-1, D-Dimer) as well as a significant increase in factors related to liver regeneration (FGF-19 and HGF). CONCLUSION: Radioembolization activates liver regeneration, produces oxidative stress, activates inflammatory cytokines and induces endothelial injury with partial activation of the coagulation cascade. These findings may have implications in the pathogenesis, prevention and therapy of REILD and in the development of new therapies to enhance hypertrophy with a surgical perspective.

The impact of the prevention strategies on the indirect effects of CMV infection in solid organ transplant recipients.

Transplant recipients receiving immunosuppressive therapy are at increased risk of active cytomegalovirus (CMV) infection and disease. Without appropriate prophylaxis, as many as 80% of solid organ transplant recipients may experience CMV infection. In addition to the direct effects of CMV, infection may be associated with a range of indirect effects, including an increase in risk of other infections, as well as a higher incidence of rejection, graft loss and death. The indirect effects of CMV infection can vary depending on the transplanted organ. For example, CMV-infected kidney transplant recipients may be at increased risk of cardiovascular disease and diabetes, while CMV infection in liver transplant recipients may potentiate hepatitis C infection and increase the risk of post-transplant lymphoproliferative disease. Indirect effects result from a number of pathological processes, including immune modulation and immunosuppression, generation of cytotoxic, pro-inflammatory responses, and smooth muscle proliferation. Prophylactic treatment with antiviral medication can reduce the risk of CMV disease, thereby improving graft survival and overall outcomes, particularly in kidney and heart transplant recipients. Antiviral prophylaxis should be considered for all patients at risk of CMV infection after solid organ transplantation. In this paper we review the main indirect effects of CMV infection in solid organ transplant recipients, and the impact of CMV prophylaxis on these effects.

Trial of complete weaning from immunosuppression for liver transplant recipients: factors predictive of tolerance.

Recipients of liver transplantation (LT) may develop immunological tolerance. Factors predictive of tolerance are not clearly understood. Transplant recipients with normal liver function tests and without active viral hepatitis or autoimmune disease who presented with side effects of immunosuppression or a high risk of de novo malignancies were selected to participate in this prospective study. Twenty-four patients fulfilled the inclusion criteria and, therefore, underwent a gradual reduction of immunosuppression. Tolerance was defined as normal liver function tests after immunosuppression withdrawal. Basal clinical and immunological characteristics, including lymphocyte counts and subpopulations (T, B, natural killer, CD4(+) , CD8(+) , and regulatory T cells) and the phytohemagglutinin stimulation index (SI), were compared for tolerant and nontolerant patients. Fifteen of the 24 patients (62.5%) were tolerant at a median of 14 months (interquartile range = 8.5-22.5 months) after complete immunosuppression withdrawal. Tolerant patients had a longer median interval between transplantation and inclusion in the study (156 for tolerant patients versus 71 months for nontolerant patients, P = 0.003) and a lower median SI (7.49 for tolerant patients versus 41.73 for nontolerant patients, P = 0.01). We identified 3 groups of patients with different probabilities of tolerance: in the first group (n = 7 for an interval > 10 years and an SI < 20), 100% reached tolerance; in the second group (n = 10 for an interval > 10 years and an SI > 20 or an interval < 10 years and an SI < 20), 60% reached tolerance; and in the third group (n = 7 for an interval < 10 years and an SI > 20), 29% reached tolerance. In conclusion, a high proportion of select LT recipients can reach tolerance over the long term. Two simple basal variables-the time from transplantation and the SI-may help to identify these patients.

New concepts and best practices for management of pre- and post-transplantation cancer.

Solid-organ transplant recipients are at increased risk of developing cancer compared with the general population. Tumours can arise de novo, as a recurrence of a preexisting malignancy, or from the donated organ. The ATOS (Aula sobre Trasplantes de Órganos Sólidos; the Solid-Organ Transplantation Working Group) group, integrated by Spanish transplant experts, meets annually to discuss current advances in the field. In 2011, the 11th edition covered a range of new topics on cancer and transplantation. In this review we have highlighted the new concepts and best practices for managing cancer in the pre-transplant and post-transplant settings that were presented at the ATOS meeting. Immunosuppression plays a major role in oncogenesis in the transplant recipient, both through impaired immunosurveillance and through direct oncogenic activity. It is possible to transplant organs obtained from donors with a history of cancer as long as an effective minimization of malignancy transmission strategy is followed. Tumour-specific wait-periods have been proposed for the increased number of transplantation candidates with a history of malignancy; however, the patient's individual risk of death from organ failure must be taken into consideration. It is important to actively prevent tumour recurrence, especially the recurrence of hepatocellular carcinoma in liver transplant recipients. To effectively manage post-transplant malignancies, it is essential to proactively monitor patients, with long-term intensive screening programs showing a reduced incidence of cancer post-transplantation. Proposed management strategies for post-transplantation malignancies include viral monitoring and prophylaxis to decrease infection-related cancer, immunosuppression modulation with lower doses of calcineurin inhibitors, and addition of or conversion to inhibitors of the mammalian target of rapamycin.

Screening of de novo tumors after liver transplantation.

De novo malignancies are frequent complications after liver transplantation. They are one of the leading causes of late death. Some authors have reported promising results following implementation of extensive cancer surveillance programs. Screening protocols might benefit patients by providing a diagnosis at an earlier stage when tumors may be cured. These protocols should be based on the specific risk factors of every patient. Unfortunately, the scientific evidence supporting screening protocols is still very weak both in the general population and in the transplant patients. On this basis, there is not enough evidence to recommend routine screening for all liver transplant recipients, apart from the recommendations accepted for the general population. Multicenter studies in selected groups of patients at high risk for malignancy may be the only way of defining the potential benefit of screening programs post-transplantation.

[III Consensus Meeting of the Spanish Society of Liver Transplantation. Hepatitis C, living-donor liver transplantation, quality of liver grafts and of liver transplantation programs]. / III Reunión de consenso de la Sociedad Española de Trasplante Hepático (SETH). Hepatitis C, trasplante hepático de donante vivo, calidad de los injertos hepáticos y calidad de los programas de trasplante hepático.

The constant updating in the field of liver transplant led to the holding of the III Consensus Meeting of the Spanish Liver Transplant Association. Three current topics of great clinical interest were debated during this meeting; transplant in patients with liver cirrhosis due to hepatitis C, live donor liver transplant and the evaluation of the quality of liver grafts. A subject of great interest to Liver Transplant Units was also discussed: the assessment of their quality.

Risk factors of lung, head and neck, esophageal, and kidney and urinary tract carcinomas after liver transplantation: the effect of smoking withdrawal.

Liver transplant recipients have an increased risk of malignancy. Smoking is related to some of the most frequent causes of posttransplant malignancy. The incidence and risk factors for the development of neoplasia related to smoking (head and neck, lung, esophageal, and kidney and urinary tract carcinomas) were studied in 339 liver transplant recipients. Risk factors for the development of smoking-related neoplasia were also studied in 135 patients who had a history of smoking so that it could be determined whether smoking withdrawal was associated with a lower risk of malignancy. After a mean follow-up of 7.5 years, 26 patients were diagnosed with 29 smoking-related malignancies. The 5- and 10-year actuarial rates were 5% and 13%, respectively. In multivariate analysis, smoking and older age were independently associated with a higher risk of malignancy. In the smoker subgroup, the variables related to a higher risk of malignancy were active smoking and older age. In conclusion, smoking withdrawal after liver transplantation may have a protective effect against the development of neoplasia.

Analysis of prognostic factors after yttrium-90 radioembolization of advanced hepatocellular carcinoma.

PURPOSE: To analyze which patient-, tumor-, and treatment-related factors may influence outcome after (90)Y radioembolization ((90)Y-RE) for hepatocellular carcinoma (HCC). PATIENTS AND METHODS: Seventy-two consecutive patients with advanced HCC treated with (90)Y-RE were studied to detect which factors may have influenced response to treatment and survival. RESULTS: Median overall survival was 13 months (95% confidence interval, 9.6-16.3 months). In univariate analysis, survival was significantly better in patients with one to five lesions (19 vs. 8 months, p = 0.001) and in patients with alpha-fetoprotein <52 UI/mL (24 vs. 11 months, p = 0.002). The variation in target tumor size and the appearance of new lesions were analyzed among 50 patients with measurable tumors. A decrease in target tumor size was observed in most patients, and the intensity of such decrease was not associated with any of the factors under study. Patients who developed new lesions in the treated liver (and also in the nontargeted liver) at month 3 more frequently had more than five nodules, bilobar disease, and alpha-fetoprotein >52 UI/mL, and their survival in the multivariate analysis was significantly worse (hazard ratio, 4.7; 95% confidence interval, 13-1.73) (p = 0.002). CONCLUSIONS: Yttrium-90 radioembolization results in control of target lesions in the majority of patients with HCC but does not prevent the development of new lesions. Survival of patients treated with (90)Y-RE seems to depend largely on factors related to the aggressiveness of the disease (number of nodules, levels of alpha-fetoprotein, and presence of microscopic disease).

De novo malignancies following liver transplantation: impact and recommendations.

1. De novo malignancy is one of the leading causes of late mortality after liver transplantation. 2. The risks of skin cancers and lymphoma are more than 10-fold greater than the risks in an age-matched and sex-matched general population. 3. Some types of neoplasia, such as lung, head and neck, and colorectal cancer, are more frequent in liver transplant recipients than in an age-matched and sex-matched population. The risks of other frequent malignancies, such as prostate and breast cancer, do not seem to be increased. 4. The most important risks for posttransplant malignancy are Epstein-Barr virus seronegativity (for lymphoma), sun exposure (for skin cancer), smoking, and increasing age. 5. Despite the absence of evidence, general recommendations (such as avoidance of overimmunosuppression, sunlight protection, and cessation of smoking) should be given. Screening protocols may help to detect neoplasia at an early stage of disease.

Usefulness of a program of neoplasia surveillance in liver transplantation. A preliminary report.

De novo malignancies are frequent complications after liver transplantation. Aim of the study is to evaluate whether a surveillance program for malignancy may improve patient survival. We have compared the survival after the diagnosis of malignancy (excluding cutaneous and hepatobiliary carcinomas and lymphoproliferative disease) of patients with symptomatic or incidental malignancies with patients with neoplasia diagnosed on screening. Two hundred and eighty patients with a follow-up greater than three months were followed for a median of 77.5 months (total follow-up: 1515 patient-yr). Thirty-three patients developed 41 malignancies. When compared with general population, the entire cohort of liver transplant recipients had a significantly higher risk of malignancy (relative risk: 2.34), gastrointestinal tract (relative risk: 2.52), urological tract (relative risk: 2.94) and head and neck cancer (relative risk: 4.14), and cancer-related death (relative risk: 2.35). All nine patients diagnosed with cancer with active screening are currently alive and free of malignancy after a median follow-up of 25 months. By contrast, 18/24 patients with diagnosis of cancer prompted by symptoms or incidentally diagnosed died as a consequence of the cancer (median survival: 13.5 months). The difference in survival between both groups was significant (p = 0.002). In conclusion, a close surveillance protocol for the diagnosis of malignancy could be life-saving in liver transplant recipients.