Crucial neuroprotective roles of the metabolite BH4 in dopaminergic neurons.

Dopa-responsive dystonia (DRD) and Parkinson's disease (PD) are movement disorders caused by the dysfunction of nigrostriatal dopaminergic neurons. Identifying druggable pathways and biomarkers for guiding therapies is crucial due to the debilitating nature of these disorders. Recent genetic studies have identified variants of GTP cyclohydrolase-1 (GCH1), the rate-limiting enzyme in tetrahydrobiopterin (BH4) synthesis, as causative for these movement disorders. Here, we show that genetic and pharmacological inhibition of BH4 synthesis in mice and human midbrain-like organoids accurately recapitulates motor, behavioral and biochemical characteristics of these human diseases, with severity of the phenotype correlating with extent of BH4 deficiency. We also show that BH4 deficiency increases sensitivities to several PD-related stressors in mice and PD human cells, resulting in worse behavioral and physiological outcomes. Conversely, genetic and pharmacological augmentation of BH4 protects mice from genetically- and chemically induced PD-related stressors. Importantly, increasing BH4 levels also protects primary cells from PD-affected individuals and human midbrain-like organoids (hMLOs) from these stressors. Mechanistically, BH4 not only serves as an essential cofactor for dopamine synthesis, but also independently regulates tyrosine hydroxylase levels, protects against ferroptosis, scavenges mitochondrial ROS, maintains neuronal excitability and promotes mitochondrial ATP production, thereby enhancing mitochondrial fitness and cellular respiration in multiple preclinical PD animal models, human dopaminergic midbrain-like organoids and primary cells from PD-affected individuals. Our findings pinpoint the BH4 pathway as a key metabolic program at the intersection of multiple protective mechanisms for the health and function of midbrain dopaminergic neurons, identifying it as a potential therapeutic target for PD.

Use of failure-to-rescue after emergency surgery as a dynamic indicator of hospital resilience during the COVID-19 pandemic. A multicenter retrospective propensity score-matched cohort study.

BACKGROUND: Surgical failure-to-rescue (FTR, death rate following complications) is a reliable cross-sectional quality of care marker, but has not been evaluated dynamically. We aimed to study changes in FTR following emergency surgery during the COVID-19 pandemic. MATERIAL AND METHODS: Matched cohort study including all COVID-19-non-infected adult patients undergoing emergency general surgery in 25 Spanish hospitals during COVID-19 pandemic peak (March-April 2020), non-peak (May-June 2020), and 2019 control periods. A propensity score-matched comparative analysis was conducted using a logistic regression model, in which period was regressed on observed baseline characteristics. Subsequently, a mixed effects logistic regression model was constructed for each variable of interest. Main variable was FTR. Secondary variables were post-operative complications, readmissions, reinterventions, and length of stay. RESULTS: 5003 patients were included (948, 1108, and 2947 in the pandemic peak, non-peak, and control periods), with comparable clinical characteristics, prognostic scores, complications, reintervention, rehospitalization rates, and length of stay across periods. FTR was greater during the pandemic peak than during non-peak and pre-pandemic periods (22.5% vs. 17.2% and 12.7%), being this difference confirmed in adjusted analysis (odds ratio [OR] 2.13, 95% confidence interval [95% CI] 1.27-3.66). There was sensible inter-hospital variability in FTR changes during the pandemic peak (median FTR change +8.77%, IQR 0-29.17%) not observed during the pandemic non-peak period (median FTR change 0%, IQR -6.01-6.72%). Greater FTR increase was associated with higher COVID-19 incidence (OR 2.31, 95% CI 1.31-4.16) and some hospital characteristics, including tertiary level (OR 3.07, 95% CI 1.27-8.00), medium-volume (OR 2.79, 95% CI 1.14-7.34), and high basal-adjusted complication risk (OR 2.21, 95% CI 1.07-4.72). CONCLUSION: FTR following emergency surgery experienced a heterogeneous increase during different periods of the COVID-19 pandemic, suggesting it to behave as an indicator of hospital resilience. FTR monitoring could facilitate identification of centres in special needs during ongoing health care challenges.

P-POSSUM as mortality predictor in COVID-19-infected patients submitted to emergency digestive surgery. A retrospective cohort study.

BACKGROUND: COVID-19 infection is associated with a higher mortality rate in surgical patients, but surgical risk scores have not been validated in the emergency setting. We aimed to study the capacity for postoperative mortality prediction of the P-POSSUM score in COVID-19-positive patients submitted to emergency general and digestive surgery. MATERIAL AND METHODS: Consecutive patients undergoing emergency general and digestive surgery from March to June 2020, and from March to June 2019 in 25 Spanish hospitals were included in a retrospective cohort study. MAIN OUTCOME: 30-day mortality. P-POSSUM discrimination was quantified by the area under the curve (AUC) of ROC curves; calibration was assessed by linear regression slope (ß estimator); and sensitivity and specificity were expressed as percentage and 95% confidence interval (CI). RESULTS: 4988 patients were included: 177 COVID-19-positive; 2011 intra-pandemic COVID-19-negative; and 2800 pre-pandemic. COVID-19-positive patients were older, with higher surgical risk, more advanced pathologies, and higher P-POSSUM values (1.79% vs. 1.09%, p < 0.001, in both the COVID-19-negative and control cohort). 30-day mortality in the COVID-19-positive, intra-pandemic COVID-19-negative and pre-pandemic cohorts were: 12.9%, 4.6%, and 3.2%. The P-POSSUM predictive values in the three cohorts were, respectively: AUC 0.88 (95% CI 0.81-0.95), 0.89 (95% CI 0.87-0.92), and 0.91 (95% CI 0.88-0.93); ß value 0.97 (95% CI 0.74-1.2), 0.99 (95% CI 0.82-1.16), and 0.78 (95% CI 0.74-0.82); sensitivity 83% (95% CI 61-95), 91% (95% CI 84-96), and 89% (95% CI 80-94); and specificity 81% (95% CI 74-87), 76% (95% CI 74-78), and 80% (95% CI 79-82). CONCLUSION: The P-POSSUM score showed a good predictive capacity for postoperative mortality in COVID-19-positive patients submitted to emergency general and digestive surgery.

The ubiquitin ligase HOIL-1L regulates immune responses by interacting with linear ubiquitin chains.

The Linear Ubiquitin Chain Assembly Complex (LUBAC), composed of HOIP, HOIL-1L, and SHARPIN, promotes tumor necrosis factor (TNF)-dependent NF-κB signaling in diverse cell types. HOIL-1L contains an Npl4 Zinc Finger (NZF) domain that specifically recognizes linear ubiquitin chains, but its physiological role in vivo has remained unclear. Here, we demonstrate that the HOIL-1L NZF domain has important regulatory functions in inflammation and immune responses in mice. We generated knockin mice (Hoil-1l T201A;R208A/T201A;R208A ) expressing a HOIL-1L NZF mutant and observed attenuated responses to TNF- and LPS-induced shock, including prolonged survival, stabilized body temperature, reduced cytokine production, and liver damage markers. Cells derived from Hoil-1l T201A;R208A/T201A;R208A mice show reduced TNF-dependent NF-κB activation and incomplete recruitment of HOIL-1L into TNF Receptor (TNFR) Complex I. We further show that HOIL-1L NZF cooperates with SHARPIN to prevent TNFR-dependent skin inflammation. Collectively, our data suggest that linear ubiquitin-chain binding by HOIL-1L regulates immune responses and inflammation in vivo.

The linear ubiquitin chain assembly complex (LUBAC) generates heterotypic ubiquitin chains.

The linear ubiquitin chain assembly complex (LUBAC) is the only known ubiquitin ligase for linear/Met1-linked ubiquitin chain formation. One of the LUBAC components, heme-oxidized IRP2 ubiquitin ligase 1 (HOIL-1L), was recently shown to catalyse oxyester bond formation between ubiquitin and some substrates. However, oxyester bond formation in the context of LUBAC has not been directly observed. Here, we present the first 3D reconstruction of human LUBAC obtained by electron microscopy and report its generation of heterotypic ubiquitin chains containing linear linkages with oxyester-linked branches. We found that this event depends on HOIL-1L catalytic activity. By cross-linking mass spectrometry showing proximity between the catalytic RING-in-between-RING (RBR) domains, a coordinated ubiquitin relay mechanism between the HOIL-1-interacting protein (HOIP) and HOIL-1L ligases is suggested. In mouse embryonic fibroblasts, these heterotypic chains were induced by TNF, which is reduced in cells expressing an HOIL-1L catalytic inactive mutant. In conclusion, we demonstrate that LUBAC assembles heterotypic ubiquitin chains by the concerted action of HOIP and HOIL-1L.

Site-specific ubiquitination of the E3 ligase HOIP regulates apoptosis and immune signaling.

HOIP, the catalytic component of the linear ubiquitin chain assembly complex (LUBAC), is a critical regulator of inflammation. However, how HOIP itself is regulated to control inflammatory responses is unclear. Here, we discover that site-specific ubiquitination of K784 within human HOIP promotes tumor necrosis factor (TNF)-induced inflammatory signaling. A HOIP K784R mutant is catalytically active but shows reduced induction of an NF-κB reporter relative to wild-type HOIP. HOIP K784 is evolutionarily conserved, equivalent to HOIP K778 in mice. We generated HoipK778R/K778R knock-in mice, which show no overt developmental phenotypes; however, in response to TNF, HoipK778R/K778R mouse embryonic fibroblasts display mildly suppressed NF-κB activation and increased apoptotic markers. On the other hand, HOIP K778R enhances the TNF-induced formation of TNFR complex II and an interaction between TNFR complex II and LUBAC. Loss of the LUBAC component SHARPIN leads to embryonic lethality in HoipK778R/K778R mice, which is rescued by knockout of TNFR1. We propose that site-specific ubiquitination of HOIP regulates a LUBAC-dependent switch between survival and apoptosis in TNF signaling.

HACE1 Prevents Lung Carcinogenesis via Inhibition of RAC-Family GTPases.

HACE1 is an E3 ubiquitin ligase with important roles in tumor biology and tissue homeostasis. Loss or mutation of HACE1 has been associated with the occurrence of a variety of neoplasms, but the underlying mechanisms have not been defined yet. Here, we report that HACE1 is frequently mutated in human lung cancer. In mice, loss of Hace1 led to enhanced progression of KRasG12D -driven lung tumors. Additional ablation of the oncogenic GTPase Rac1 partially reduced progression of Hace1-/- lung tumors. RAC2, a novel ubiquitylation target of HACE1, could compensate for the absence of its homolog RAC1 in Hace1-deficient, but not in HACE1-sufficient tumors. Accordingly, ablation of both Rac1 and Rac2 fully averted the increased progression of KRasG12D -driven lung tumors in Hace1-/- mice. In patients with lung cancer, increased expression of HACE1 correlated with reduced levels of RAC1 and RAC2 and prolonged survival, whereas elevated expression of RAC1 and RAC2 was associated with poor prognosis. This work defines HACE1 as a crucial regulator of the oncogenic activity of RAC-family GTPases in lung cancer development. SIGNIFICANCE: These findings reveal that mutation of the tumor suppressor HACE1 disrupts its role as a regulator of the oncogenic activity of RAC-family GTPases in human and murine lung cancer. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/14/3009/F1.large.jpg.

RST1 and RIPR connect the cytosolic RNA exosome to the Ski complex in Arabidopsis.

The RNA exosome is a key 3'-5' exoribonuclease with an evolutionarily conserved structure and function. Its cytosolic functions require the co-factors SKI7 and the Ski complex. Here we demonstrate by co-purification experiments that the ARM-repeat protein RESURRECTION1 (RST1) and RST1 INTERACTING PROTEIN (RIPR) connect the cytosolic Arabidopsis RNA exosome to the Ski complex. rst1 and ripr mutants accumulate RNA quality control siRNAs (rqc-siRNAs) produced by the post-transcriptional gene silencing (PTGS) machinery when mRNA degradation is compromised. The small RNA populations observed in rst1 and ripr mutants are also detected in mutants lacking the RRP45B/CER7 core exosome subunit. Thus, molecular and genetic evidence supports a physical and functional link between RST1, RIPR and the RNA exosome. Our data reveal the existence of additional cytosolic exosome co-factors besides the known Ski subunits. RST1 is not restricted to plants, as homologues with a similar domain architecture but unknown function exist in animals, including humans.

Roles of ubiquitin in autophagy and cell death.

The balance between cell survival and cell death is often lost in human pathologies such as inflammation and cancer. Autophagy plays a critical role in cell survival: essential nutrients are generated by autophagy-dependent degradation and recycling of cellular garbage. On the other hand, cell death is induced by different programs, such as apoptosis, pyroptosis, and necroptosis. Emerging evidence is revealing how cell survival and cell death pathways are coordinated to determine cell fate. For instance, posttranslational modification of proteins with ubiquitin regulates many steps of autophagy and cell death pathways. In this review article, we will discuss how the ubiquitin system influences cell death and autophagy.

Surgical electronic logbook: A step forward.

INTRODUCTION: The surgical electronic logbook (surgical e-logbook) aims to: simplify registration of the training activities of surgical residents, and to obtain reliable and detailed reports about these activities for resident evaluation. METHODS: The surgical e-logbook is a unique and shared database. Residents prospectively record their activities in 3 areas: surgical, scientific and teaching. We can access activity reports that are constantly updated. RESULTS: Study period using the surgical e-logbook: Between June 2011 and May 2013. Number of surgeries reported: 4,255. Number of surgical procedures reported: 11,907. Number of surgeries per resident per year reported: 250. Number of surgical procedures per resident per year reported: 700. Surgical activity as a primary surgeon during the first year of residency is primarily in emergency surgery (68,01%) and by laparotomy (97,73%), while during the fifth year of residency 51,27% is performed in elective surgery and laparoscopy is used in 23,10% of cases. During this period, residents participated in a total of 11 scientific publications, 75 conference presentations and 69 continuing education activities. CONCLUSIONS: The surgical e-logbook is a useful tool that simplifies the recording and analysis of data about surgical and scientific activities of the residents. It is a step forward in the evaluation of the training of surgical residents, however, is only an intermediate step towards the development of a larger Spanish registry.

Transanal endoscopic surgery in rectal cancer.

Total mesorectal excision (TME) is the standard treatment for rectal cancer, but complications are frequent and rates of morbidity, mortality and genitourinary alterations are high. Transanal endoscopic microsurgery (TEM) allows preservation of the anal sphincters and, via its vision system through a rectoscope, allows access to rectal tumors located as far as 20 cm from the anal verge. The capacity of local surgery to cure rectal cancer depends on the risk of lymph node invasion. This means that correct preoperative staging of the rectal tumor is necessary. Currently, local surgery is indicated for rectal adenomas and adenocarcinomas invading the submucosa, but not beyond (T1). Here we describe the standard technique for TEM, the different types of equipment used, and the technical limitations of this approach. TEM to remove rectal adenoma should be performed in the same way as if the lesion were an adenocarcinoma, due to the high percentage of infiltrating adenocarcinomas in these lesions. In spite of the generally good results with T1, some authors have published surprisingly high recurrence rates; this is due to the existence of two types of lesions, tumors with good and poor prognosis, divided according to histological and surgical factors. The standard treatment for rectal adenocarcinoma T2N0M0 is TME without adjuvant therapy. In this type of adenocarcinoma, local surgery obtains the best results when complete pathological response has been achieved with previous chemoradiotherapy. The results with chemoradiotherapy and TEM are encouraging, but the scientific evidence remains limited at present.

[Validation of abdominal wound dehiscence's risk model]. / Validación de un modelo de riesgo de evisceración.

INTRODUCTION: The aim of this study is to determine the usefulness of the risk model developed by van Ramshorst et al., and a modification of the same, to predict the abdominal wound dehiscence's risk in patients who underwent midline laparotomy incisions. MATERIALS AND METHODS: Observational longitudinal retrospective study. SAMPLE: Patients who underwent midline laparotomy incisions in the General and Digestive Surgery Department of the Sabadell's Hospital-Parc Taulí's Health and University Corporation-Barcelona, between January 1, 2010 and June 30, 2010. Dependent variable: Abdominal wound dehiscence. INDEPENDENT VARIABLES: Global risk score, preoperative risk score (postoperative variables were excluded), global and preoperative probabilities of developing abdominal wound dehiscence. SAMPLE: 176 patients. Patients with abdominal wound dehiscence: 15 (8.5%). The global risk score of abdominal wound dehiscence group (mean: 4.97; IC 95%: 4.15-5.79) was better than the global risk score of No abdominal wound dehiscence group (mean: 3.41; IC 95%: 3.20-3.62). This difference is statistically significant (P<.001). The preoperative risk score of abdominal wound dehiscence group (mean: 3.27; IC 95%: 2.69-3.84) was better than the preoperative risk score of No abdominal wound dehiscence group (mean: 2.77; IC 95%: 2.64-2.89), also a statistically significant difference (P<.05). The global risk score (area under the ROC curve: 0.79) has better accuracy than the preoperative risk score (area under the ROC curve: 0.64). CONCLUSION: The risk model developed by van Ramshorst et al. to predict the abdominal wound dehiscence's risk in the preoperative phase has a limited usefulness. Additional refinements in the preoperative risk score are needed to improve its accuracy.

[Measurement of lactic acid in multiple injury patients and its usefulness as a predictor of multiorgan failure and mortality]. / Medición del ácido láctico en pacientes politraumatizados y su utilidad como factor predictor de mortalidad y fallo multiorgánico.

INTRODUCTION: The use of lactic acid as marker of occult hyperfusion and its relationship with multiorgan failure (MOF) and/or mortality is a subject of debate. MATERIAL AND METHOD: A prospective study was conducted on multiple injury patients over 16 years of age in critical care areas. The lactic acid was measured at the beginning and at 24 hours of the trauma and associating it with the patient morbidity and mortality. RESULTS: A total of 342 patients, with a mean injury severity score of 24.1, were included. The patients who survived had an initial, and 24 hours after the trauma, lactic acid of 27.8 mg/dl and 17.9 mg/dl, respectively, (normal values less than 22 mg/dl), increasing to 36.5mg/dl and 40.2mg/dl, respectively, in those who died. There were no differences between the initial lactic acid in patients with and without MOF, being increased at 24 hours in those who had MOF (17.8 vs 26.7). The patients with a lactic acid that got worse or remained abnormal at 24 hours had a higher mortality than those in which it remained the same or improved (25% - 17.1% vs 6.3% - 0.8%), with the percentage of patients with MOF also increasing (40.6% - 32.8% vs 14.9% - 11.1%). In haemodynamically stable patients, there was also a higher mortality when the lactic acid got worse or remained abnormal in the first 24 hours (23.8% - 19.2% vs 8.8% - 0%), as well as a higher percentage of MOF (38.1% - 26.9% vs 10.9% - 7.6%). CONCLUSIONS: The lactic acid results in the first 24 hours of the multiple injury patient are associated with mortality and MOF, even when the patient is haemodynamically stable.

[Four years experience with the AEC residents E-Book]. / Cuatro años de experiencia con el libro informático del residente de la AEC.

INTRODUCTION: The introduction of the Spanish Association of Surgeons resident's electronic book (AEC-E-Book), has meant that we can perform particular and overall assessments of each resident. The objective of this article has been to find out the mean health care, scientific and surgical activities according to the speciality program. MATERIAL AND METHOD: A register of the activities of residents in the AEC-E-Book. The overall activity per year and per rotation has been measured. The relationships of assisted interventions performed and their level of complexity have been analysed. The mean scientific and health care activities and the mean on-call periods per month. RESULTS: A total of 8 residents have registered their activity in the AEC-E-Book since the year 2004. They assisted in a mean of 1514 operations, of which 922 were performed as surgeon (62%). They assisted in 185 laparoscopic interventions, of which they performed 72 (39%). As surgeon, 864 (94%) of the 922 procedures 64% were level 1, 75% level 2, and 53% were level 3. They were on-call a mean of 5.75 times per month. They attended a total of 21 courses and congresses during residency. They took part in 24 presentations and posters, as well as in 6 journal publications during residence. CONCLUSIONS: The AEC-E-Book enables the activity of the resident to be continually assessed. We have been able to find out the mean activities carried out by each resident during a particular rotation and year, thus being able to know exactly if they have fulfilled the defined minimums.