Custom-Made Oocytes to Clone Non-human Primates.

In this issue of Cell, Liu et al. (2018) report the birth of two healthy cloned macaque monkeys using fetal fibroblasts. By artificially enhancing the arsenal of epigenetic modifiers in the oocyte, the authors overcome the earliest roadblocks that take place during somatic cell nuclear transfer (SCNT).

Follicular dendritic cells emerge from ubiquitous perivascular precursors.

The differentiation of follicular dendritic cells (FDC) is essential to the remarkable microanatomic plasticity of lymphoid follicles. Here we show that FDC arise from ubiquitous perivascular precursors (preFDC) expressing platelet-derived growth factor receptor ß (PDGFRß). PDGFRß-Cre-driven reporter gene recombination resulted in FDC labeling, whereas conditional ablation of PDGFRß(+)-derived cells abolished FDC, indicating that FDC originate from PDGFRß(+) cells. Lymphotoxin-α-overexpressing prion protein (PrP)(+) kidneys developed PrP(+) FDC after transplantation into PrP(-) mice, confirming that preFDC exist outside lymphoid organs. Adipose tissue-derived PDGFRß(+) stromal-vascular cells responded to FDC maturation factors and, when transplanted into lymphotoxin ß receptor (LTßR)(-) kidney capsules, differentiated into Mfge8(+)CD21/35(+)FcγRIIß(+)PrP(+) FDC capable of trapping immune complexes and recruiting B cells. Spleens of lymphocyte-deficient mice contained perivascular PDGFRß(+) FDC precursors whose expansion required both lymphoid tissue inducer (LTi) cells and lymphotoxin. The ubiquity of preFDC and their strategic location at blood vessels may explain the de novo generation of organized lymphoid tissue at sites of lymphocytic inflammation.

Author Correction: Deconstructive diversification of cyclic amines.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Deconstructive diversification of cyclic amines.

Deconstructive functionalization involves carbon-carbon (C-C) bond cleavage followed by bond construction on one or more of the constituent carbons. For example, ozonolysis1 and olefin metathesis2,3 have allowed each carbon in C=C double bonds to be viewed as a functional group. Despite the substantial advances in deconstructive functionalization involving the scission of C=C double bonds, there are very few methods that achieve C(sp3)-C(sp3) single-bond cleavage and functionalization, especially in relatively unstrained cyclic systems. Here we report a deconstructive strategy to transform saturated nitrogen heterocycles such as piperidines and pyrrolidines, which are important moieties in bioactive molecules, into halogen-containing acyclic amine derivatives through sequential C(sp3)-N and C(sp3)-C(sp3) single-bond cleavage followed by C(sp3)-halogen bond formation. The resulting acyclic haloamines are versatile intermediates that can be transformed into various structural motifs through substitution reactions. In this way we achieve the skeletal remodelling of cyclic amines, an example of scaffold hopping. We demonstrate this deconstructive strategy by the late-stage diversification of proline-containing peptides.

Direct oral anticoagulants versus vitamin K antagonists in patients with atrial fibrillation and stage 5 chronic kidney disease under dialysis: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: In patients with atrial fibrillation (AF) and normal or slightly impaired renal function, the use of direct oral anticoagulants (DOACs) is preferable to vitamin K antagonists (VKAs). However, in patients undergoing hemodialysis, the efficacy, and safety of DOACs compared with VKAs are still unknown. PURPOSE: To review current evidence about the safety and efficacy of DOACs compared to VKAs, in patients with AF and chronic kidney disease under hemodialysis. METHODS: We systematically searched PubMed, Scopus, and Cochrane databases for RCTs comparing DOACs with VKAs for anticoagulation in patients with AF on dialysis therapy. Outcomes of interest were: (1) stroke; (2) major bleeding; (3) cardiovascular mortality; and (4) all-cause mortality. Statistical analysis was performed using RevMan 5.1.7 and heterogeneity was assessed by I2 statistics. RESULTS: Three randomized controlled trials were included, comprising a total of 383 patients. Of these, 218 received DOACs (130 received apixaban; 88 received rivaroxaban), and 165 were treated with VKAs (116 received warfarin; 49 received phenprocoumon). The incidence of stroke was significantly lower in patients treated with DOACs (4.7%) compared with those using VKAs (9.5%) (RR 0.42; 95% CI 0.18-0.97; p = 0.04; I2 = 0%). However, the difference was not statistically significant in the case of ischemic stroke specifically (RR 0.42; 95% CI 0.17-1.04; p = 0.06; I2 = 0%). As for the major bleeding outcome, the DOAC group (11%) had fewer events than the VKA group (13.9%) but without statistical significance (RR 0.75; 95% CI 0.45-1.28; p = 0.29; I2 = 0%). There was no significant difference between groups regarding cardiovascular mortality (RR 1.23; 95% CI 0.66-2.29; p = 0.52; I2 = 13%) and all-cause mortality (RR 0.98; 95% CI 0.77-1.24; p = 0.84; I2 = 16%). CONCLUSION: This meta-analysis suggests that in patients with AF on dialysis, the use of DOACs was associated with a significant reduction in stroke, and a numerical trend of less incidence of major bleeding compared with VKAs, but in this case with no statistical significance. Results may be limited by a small sample size or insufficient statistical power.

Effect of different levels of whole corn germ on energy values and ileal digestibility in broilers.

This study evaluated the effects of broiler age (A) and levels of replacement (L) of control diet (CD) on the utilization of energy and nutrients of whole corn germ. 720 one-day-old broilers (b) were allocated at completely randomized design to six treatments and six replicates, in three assays: pre-starter (1-8 days, 10 b/cage), starter (15-22 days, 6 b/cage), and grower (28-35 days, 4 b/cage) phases. The treatments were: CD and four test diets (L): 100, 150, 200, 250, or 300 g kg-1 of the CD replaced by WCG levels. The data were adjusted to the response surface model. The stationary points for apparent energy metabolizable (AME) and AME corrected for nitrogen balance (AMEn) were: 4173 and 3591 kcal kg-1, respectively, and coefficients of gross energy (AMCGE), crude protein (AMCCP), dry matter (AMCDM), and ether extract (AMCEE) were: 49.3, 40.4, 72.6, and 61.3%, respectively; and Ileal digestibility coefficient of crude protein (IDCCP), dry matter (IDCDM), digestibility crude protein values (DCP), and digestibility dry matter value (DDM) were: 78.0, 57.96, 8.50, and 56.17%, respectively. The EP for AMEn was at 18 days of age, 28 g kg-1 WCG. There was a correlation between A and L on digestibility and metabolisability of nutrient's WCG.

Performance, nutrient utilization and meat quality traits in Bos indicus cattle: a meta-analysis examining the effect of residual feed intake.

This meta-analysis aims to investigate the effects of residual feed intake (RFI) phenotype on performance, nutrient utilization and meat quality traits in Zebu (Bos indicus) cattle. Twenty-three peer-reviewed publications with 37 treatment means were included in the dataset. Weighted mean difference analysis compared animals categorized into low RFI (more efficient) versus medium or high RFI (less efficient) groups. Data heterogeneity via meta-regression and subgroup analysis, considering variables such as animal age, sex class, experimental duration, RFI group, dietary concentrate, and estimated metabolizable energy intake were also explored. The predominant genetic group of cattle in the dataset was Nellore (89.18%), followed by Brahman (10.81%). More efficient animals (low RFI phenotype) exhibited less dry matter intake (DMI; P < 0.010) than medium or high RFI animals (-0.95 kg vs. -0.42 kg/d). Cattle dietary crude protein and fiber digestibility were consistent across RFI groups (P > 0.05), while dietary ether extract digestibility tended to decrease (P = 0.050) in low RFI animals (-13.20 g/kg DM). Low RFI animals tended to increased (P = 0.065) ribeye area (REA) compared to the high/medium RFI groups, while carcass backfat thickness (BFT) decreased (P = 0.042) compared to high/medium RFI groups. Moreover, there was an increase (P < 0.001) of 0.22 kg in Warner-Bratzler shear force (WBSF) and a reduction (P < 0.001) in the myofibrillar fragmentation index (MFI) in low RFI animals. Meat color parameters (lightness [L*] and yellowness [b*]) and visual marbling scores were consistent (P > 0.05) across RFI groups. In conclusion, Zebu cattle classified as efficient (low RFI) exhibited reduced DMI, which improves their feed efficiency. However, BFT and meat quality parameters such as tenderness (WBSF and MFI) and redness [a*] were compromised by low RFI phenotype, highlighting the challenge of enhancing feed efficiency and meat quality traits in Zebu cattle.

Non-random interactions within and across guilds shape the potential to coexist in multi-trophic ecological communities.

Theory posits that the persistence of species in ecological communities is shaped by their interactions within and across trophic guilds. However, we lack empirical evaluations of how the structure, strength and sign of biotic interactions drive the potential to coexist in diverse multi-trophic communities. Here, we model community feasibility domains, a theoretically informed measure of multi-species coexistence probability, from grassland communities comprising more than 45 species on average from three trophic guilds (plants, pollinators and herbivores). Contrary to our hypothesis, increasing community complexity, measured either as the number of guilds or community richness, did not decrease community feasibility. Rather, we observed that high degrees of species self-regulation and niche partitioning allow for maintaining larger levels of community feasibility and higher species persistence in more diverse communities. Our results show that biotic interactions within and across guilds are not random in nature and both structures significantly contribute to maintaining multi-trophic diversity.

Photo- and Metal-Mediated Deconstructive Approaches to Cyclic Aliphatic Amine Diversification.

Described herein are studies toward the core modification of cyclic aliphatic amines using either a riboflavin/photo-irradiation approach or Cu(I) and Ag(I) to mediate the process. Structural remodeling of cyclic amines is explored through oxidative C-N and C-C bond cleavage using peroxydisulfate (persulfate) as an oxidant. Ring-opening reactions to access linear aldehydes or carboxylic acids with flavin-derived photocatalysis or Cu salts, respectively, are demonstrated. A complementary ring-opening process mediated by Ag(I) facilitates decarboxylative Csp3-Csp2 coupling in Minisci-type reactions through a key alkyl radical intermediate. Heterocycle interconversion is demonstrated through the transformation of N-acyl cyclic amines to oxazines using Cu(II) oxidation of the alkyl radical. These transformations are investigated by computation to inform the proposed mechanistic pathways. Computational studies indicate that persulfate mediates oxidation of cyclic amines with concomitant reduction of riboflavin. Persulfate is subsequently reduced by formal hydride transfer from the reduced riboflavin catalyst. Oxidation of the cyclic aliphatic amines with a Cu(I) salt is proposed to be initiated by homolysis of the peroxy bond of persulfate followed by α-HAT from the cyclic amine and radical recombination to form an α-sulfate adduct, which is hydrolyzed to the hemiaminal. Investigation of the pathway to form oxazines indicates a kinetic preference for cyclization over more typical elimination pathways to form olefins through Cu(II) oxidation of alkyl radicals.

AMP kinase activation by Omega-3 polyunsaturated fatty acid protects the retina against ischemic insult: An in vitro and in vivo study.

PURPOSE: To investigate the possible beneficial effects of omega-3 polyunsaturated fatty acids (ω3-PUFAs) in ischemic retinal angiogenesis and whether AMP-activated protein kinase (AMPK) is involved. METHODS: Human retinal microvascular endothelial cells (hRMECs) were exposed to dimethyloxalylglycine (DMOG), a hypoxia-inducible factor hydroxylase inhibitor, in the presence or absence of docosahexaenoic acid (DHA) and small interfering RNA (siRNA) for AMPKα for 24 h. Ischemic factors, endothelial mesenchymal transition marker, endothelial barrier integrity, cell migration, and tube formation were evaluated. Neonatal AMPKα2-/- and control wild-type (WT) mice were submitted to an oxygen-induced retinopathy (OIR) protocol; their nursing mother mice were either fed ω3-PUFAs or not. In the end, ischemic markers and endothelial cell proliferation were evaluated in neonatal mouse retinal tissue through immunohistochemical or immunofluorescent assays among all studied groups. RESULTS: Cells exposed to DMOG displayed increased expressions of hypoxic and endothelial mesenchymal transition (vimentin) markers and barrier disarrangement of Zonula Occludens-1 compared to the control, accompanied by increased cellular migration and tube formation (p < 0.05). AMPK activity was significantly decreased. Supplementation with DHA restored the mentioned alterations compared to DMOG (p<0.05). In siRNAAMPKα-treated cells, the beneficial effects observed with DHA were abolished. DHA upregulated G-protein receptor-120 (GPR120), which promptly increased intracellular levels of calcium (p ≤ 0.001), which consequently increased Calcium/calmodulin-dependent protein kinase kinase ß expression (CaMKKß) thus phosphorylating AMPKThr172. AMPKα2-/- and wild-type (WT) OIR mice exhibited similar retinal ischemic changes, and the oral supplementation with ω3-PUFA efficiently prevented the noticed ischemic alterations only in WT mice, suggesting that AMPKα2 is pivotal in the protective effects of ω3-PUFA. CONCLUSIONS: ω3-PUFAs protect the retina from the effects of ischemic conditions, and this effect occurs via the GPR120-CaMKKß-AMPK axis. A better understanding of this mechanism might improve the control of pathological angiogenesis in retinal ischemic diseases.

The non-random assembly of network motifs in plant-pollinator networks.

Ecological processes leave distinct structural imprints on the species interactions that shape the topology of animal-plant mutualistic networks. Detecting how direct and indirect interactions between animals and plants are organised is not trivial since they go beyond pairwise interactions, but may get blurred when considering global network descriptors. Recent work has shown that the meso-scale, the intermediate level of network complexity between the species and the global network, can capture this important information. The meso-scale describes network subgraphs representing patterns of direct and indirect interactions between a small number of species, and when these network subgraphs differ statistically from a benchmark, they are often referred to as 'network motifs'. Although motifs can capture relevant ecological information of species interactions, they remain overlooked in natural plant-pollinator networks. By exploring 60 empirical plant-pollinator networks from 18 different studies with wide geographical coverage, we show that some network subgraphs are consistently under- or over-represented, suggesting the presence of worldwide network motifs in plant-pollinator networks. In addition, we found a higher proportion of densely connected network subgraphs that, based on previous findings, could reflect that species relative abundances are the main driver shaping the structure of the meso-scale on plant-pollinator communities. Moreover, we found that distinct subgraph positions describing species ecological roles (e.g. generalisation and number of indirect interactions) are occupied by different groups of animal and plant species representing their main life-history strategies (i.e. functional groups). For instance, we found that the functional group of 'bees' was over-represented in subgraph positions with a lower number of indirect interactions in contrast to the rest of floral visitors groups. Finally, we show that the observed functional group combinations within a subgraph cannot be retrieved from their expected probabilities (i.e. joint probability distributions), indicating that plant and floral visitor associations within subgraphs are not random either. Our results highlight the presence of common network motifs in plant-pollinator communities that are formed by a non-random association of plants and floral visitors functional groups.

Brain size predicts bees' tolerance to urban environments.

The rapid conversion of natural habitats to anthropogenic landscapes is threatening insect pollinators worldwide, raising concern regarding the negative consequences on their fundamental role as plant pollinators. However, not all pollinators are negatively affected by habitat conversion, as certain species find appropriate resources in anthropogenic landscapes to persist and proliferate. The reason why some species tolerate anthropogenic environments while most find them inhospitable remains poorly understood. The cognitive buffer hypothesis, widely supported in vertebrates but untested in insects, offers a potential explanation. This theory suggests that species with larger brains have enhanced behavioural plasticity, enabling them to confront and adapt to novel challenges. To investigate this hypothesis in insects, we measured brain size for 89 bee species, and evaluated their association with the degree of habitat occupancy. Our analyses revealed that bee species mainly found in urban habitats had larger brains relative to their body size than those that tend to occur in forested or agricultural habitats. Additionally, urban bees exhibited larger body sizes and, consequently, larger absolute brain sizes. Our results provide the first empirical support for the cognitive buffer hypothesis in invertebrates, suggesting that a large brain in bees could confer behavioural advantages to tolerate urban environments.

The overturn of Roe v. Wade beyond abortion: a snapshot of methotrexate accessibility for people with rheumatic and musculoskeletal diseases-a mixed methods study using Twitter data.

In June 2022, the Supreme Court of the United States (US) overturned the right established in Roe v. Wade to terminate a pregnancy. Subsequently, some states passed abortion ban laws prohibiting the use of abortive methods, including methotrexate (MTX), which has been a cornerstone drug in rheumatology. We aimed to explore and analyze Twitter data to comprehend the short-term implications of the overturn on rheumatology care. We conducted a mixed methods study using social media (SoMe) data. Tweets publicly posted using "#Methotrexate or Methotrexate" were tracked. A combination of SoMe performance data with qualitative hashtag co-occurrence analysis and content analysis was conducted. A total of 5180 posts were generated and reached approximately 40 million users. Seventy-three percent of all publications came from the US. Females posted more than males. Additionally, the three pairs of hashtags with higher co-occurrence were: #roevswade, #abortionishealthcare, and #rheumatoidarthritis. From the content analysis, three main themes were generated: (i) violence against women, (ii) health policy without public health intelligence, and (iii) call for strategic alliances in favor of public health. The combination of biological sex and state of residence could condition the use of MTX. Men will be able to continue their treatment; however, women could lose continuity of it. Inequity in access to treatment is a political decision, just as it is to reproduce inequities and vulnerabilities through the actions taken. Not having access to MTX for rheumatic and musculoskeletal diseases (RMDs) is a critical issue that endangers the physical and mental health of people with RMDs.

Low-intensity pulsed ultrasound partially reversed the deleterious effects of a severe spinal cord injury-induced bone loss and osteoporotic fracture healing in paraplegic rats.

PURPOSE: To evaluate the effects of low-intensity pulsed ultrasound (LIPUS) on the quality of femoral fracture callus formation in rats with severe osteoporosis secondary to spinal cord injury (SCI). METHODS: Forty-five male rats were equally divided into three groups: the Sham group underwent sham surgery for SCI followed by surgery for femoral fracture on day ten post-spine surgery; the SCI group sustained a complete transection of the spinal cord and a femoral fracture ten days post-SCI; and the SCI group treated with ultrasound (SCI + US), which also sustained a femoral fracture on day ten post-SCI, concomitant with daily application of LIPUS at the fracture site. RESULTS: At the non-fractured tibias, LIPUS counteracted the SCI-induced bone loss by normalizing the osteoblastic-related gene expression, decreasing resorptive area, increasing trabecular area, and decreasing RANK and RANK-L-positive areas, which resulted in higher cortical volume and stronger tibias. Likewise, LIPUS was effective at restoring bone fracture healing in SCI rats; by promoting endochondral ossification, increasing collagen deposition and OPG-positive-area, decreasing resorptive area, which led to higher density and improved microarchitecture, ultimately resulting in stronger fracture callus. CONCLUSION: At the tibias, LIPUS counteracted the SCI-induced bone loss effects by simultaneously increasing bone formation and decreasing bone resorption. We also evidenced the osteogenic effects of LIPUS at partially restoring the endochondral ossification during callus formation, leading to a newly formed tissue with improved microarchitecture and mechanical integrity. Therefore, LIPUS may be an efficient and non-invasive approach to prevent bone loss and osteoporotic fracture in SCI individuals.

Temporal dynamics of Apis mellifera (Hymenoptera: Apidae) during flowering in indeterminate soybean (Glycine max).

Soybean varieties with indeterminate growth habit are widely used in the state of Mato Grosso do Sul and are characterized by not having well-defined phenological stages. Due to the importance of bee conservation, studies on the frequency and time of visitation in indeterminate soybean are needed. Samples were collected in a 4-ha plot of soybeans not treated with insecticides. Sampling was carried out at random spots, throughout the flowering period, starting at 08h:00min, during 15 min/hour, successively until 16h:00min. Generalized Linear Models were generated and the Poisson regression model provided the best fit, reflecting the significant differences revealed by the deviance analysis. The association between bees and climatic variables was tested with the Spearman's correlation. The temporal pattern of bee visitation was independently influenced by flowering period and time of day. However climatic variables did not influence significantly bee visitation rate. In the first days of flowering, bees were more abundant, especially between 10h and 15h. These results have practical implications in the maintenance of this species during soybean management practices, contributing to a balanced coexistence between beekeepers and soybean growers, by avoiding applications of phytosanitary products during the periods of high bee visitation.

Statistical Analysis of Methotrexate Degradation by UV-C Photolysis and UV-C/TiO2 Photocatalysis.

Methotrexate (MTX) is a folic acid analog and has been used to treat a wide variety of malignant and non-malignant diseases. The wide use of these substances has led to the continuous discharge of the parent compound and its metabolites in wastewater. In conventional wastewater treatment plants, the removal or degradation of drugs is not complete. In order to study the MTX degradation by photolysis and photocatalysis processes, two reactors were used with TiO2 as a catalyst and UV-C lamps as a radiation source. H2O2 addition was also studied (absence and 3 mM/L), and different initial pHs (3.5, 7, and 9.5) were tested to define the best degradation parameters. Results were analyzed by means of ANOVA and the Tukey test. Results show that photolysis in acidic conditions with 3 mM of H2O2 added is the best condition for MTX degradation in these reactors, with a kinetic constant of 0.028 min-1. According to the ANOVA test, all considered factors (process, pH, H2O2 addition, and experimentation time) caused statistically significant differences in the MTX degradation results.

Aerobic Oxidation of 5-Hydroxymethylfurfural (HMF) in Aqueous Medium over Fe-Doped-Poly(heptazine imide) Photocatalysts: Unveiling the Bad Role of Hydroxyl Radical Generation on the Catalytic Performance.

5-hydroxymethylfurfural (HMF) oxidation in aqueous media using visible photocatalysis is a green and sustainable route for the valorization of lignocellulosic biomass derivatives. Several semiconductors have already been applied for this purpose; however, the use of Poly(heptazine imides), which has high crystallinity and a special cation exchange property that allows the replacement of the cation held between the layers of C3N4 structure by transition metal ions (TM), remains scarce. In this study, PHI(Na) was synthesized using a melamine/NaCl method and used as precursor to prepare metal (Fe, Co, Ni, or Cu)-doped PHI catalysts. The catalysts were tested for selective oxidation of HMF to 2,5-diformylfuran (DFF) in water and O2 atmosphere under blue LED radiation. The catalytic results revealed that the 0.1 wt% PHI(Fe) catalyst is the most efficient photocatalyst while higher Fe loading (1 and 2 wt%) favors the formation of Fe3+ clusters, which are responsible for the drop in HMF oxidation. Moreover, the 0.1 wt% PHI(Fe) photocatalyst has strong oxidative power due to its efficiency in H2O2 production, thus boosting the generation of nonselective hydroxyl radicals (●OH) via different pathways that can destroy HMF. We found that using 50 mM, the highest DFF production rate (393 µmol·h-1·g-1) was obtained in an aqueous medium under visible light radiation.

Detection of potential functional variants based on systems-biology: the case of feed efficiency in beef cattle.

BACKGROUND: Potential functional variants (PFVs) can be defined as genetic variants responsible for a given phenotype. Ultimately, these are the best DNA markers for animal breeding and selection, especially for polygenic and complex phenotypes. Herein, we described the identification of PFVs for complex phenotypes (in this case, Feed Efficiency in beef cattle) using a systems-biology driven approach based on RNA-seq data from physiologically relevant organs. RESULTS: The systems-biology coupled with deep molecular phenotyping by RNA-seq of liver, muscle, hypothalamus, pituitary, and adrenal glands of animals with high and low feed efficiency (FE) measured by residual feed intake (RFI) identified 2,000,936 uniquely variants. Among them, 9986 variants were significantly associated with FE and only 78 had a high impact on protein expression and were considered as PFVs. A set of 169 significant uniquely variants were expressed in all five organs, however, only 27 variants had a moderate impact and none of them a had high impact on protein expression. These results provide evidence of tissue-specific effects of high-impact PFVs. The PFVs were enriched (FDR < 0.05) for processing and presentation of MHC Class I and II mediated antigens, which are an important part of the adaptive immune response. The experimental validation of these PFVs was demonstrated by the increased prediction accuracy for RFI using the weighted G matrix (ssGBLUP+wG; Acc = 0.10 and b = 0.48) obtained in the ssGWAS in comparison to the unweighted G matrix (ssGBLUP; Acc = 0.29 and b = 1.10). CONCLUSION: Here we identified PFVs for FE in beef cattle using a strategy based on systems-biology and deep molecular phenotyping. This approach has great potential to be used in genetic prediction programs, especially for polygenic phenotypes.

A Gene Expression Signature to Select Hepatocellular Carcinoma Patients for Liver Transplantation.

OBJECTIVE: To propose a new decision algorithm combining biomarkers measured in a tumor biopsy with clinical variables, to predict recurrence after liver transplantation (LT). BACKGROUND: Liver cancer is one of the most frequent causes of cancer-related mortality. LT is the best treatment for hepatocellular carcinoma (HCC) patients but the scarcity of organs makes patient selection a critical step. In addition, clinical criteria widely applied in patient eligibility decisions miss potentially curable patients while selecting patients that relapse after transplantation. METHODS: A literature systematic review singled out candidate biomarkers whose RNA levels were assessed by quantitative PCR in tumor tissue from 138 HCC patients submitted to LT (>5 years follow up, 32% beyond Milan criteria). The resulting 4 gene signature was combined with clinical variables to develop a decision algorithm using machine learning approaches. The method was named HepatoPredict. RESULTS: HepatoPredict identifies 99% disease-free patients (>5 year) from a retrospective cohort, including many outside clinical criteria (16%-24%), thus reducing the false negative rate. This increased sensitivity is accompanied by an increased positive predictive value (88.5%-94.4%) without any loss of long-term overall survival or recurrence rates for patients deemed eligible by HepatoPredict; those deemed ineligible display marked reduction of survival and increased recurrence in the short and long term. CONCLUSIONS: HepatoPredict outperforms conventional clinical-pathologic selection criteria (Milan, UCSF), providing superior prognostic information. Accurately identifying which patients most likely benefit from LT enables an objective stratification of waiting lists and information-based allocation of optimal versus suboptimal organs.