Effect of N-acetylcysteine on motivation, seeking and relapse to ethanol self-administration.

Alcohol use disorder is a chronic and highly relapsing disorder, characterized by a loss of control over alcohol consumption and craving. Several studies suggest a key role of glutamate in this disorder. In recent years, the modulation of cystine/glutamate exchange via the xc- system has emerged as a new therapeutic alternative for reducing the excitatory glutamatergic transmission observed after ethanol self-administration in both rats and humans. The objective of this study was to determine whether a treatment with N-acetylcysteine (NAC), a cystine prodrug, could reduce ethanol self-administration, ethanol-seeking behavior and reacquisition of ethanol self-administration. Male Long Evans rats were trained to self-administer 20 percent ethanol in operant cages for several weeks. Once the consumption surpassed 1 g of ethanol/kg body weight/15 minutes, the effect of an acute intraperitoneal injection of NAC (0, 25, 50 or 100 mg/kg) 1 hour before the beginning of each test was evaluated on different aspects of the operant self-administration behavior. We demonstrated antimotivational properties of NAC (100 mg/kg), as ethanol-reinforced responding was reduced in a fixed ratio (-35 percent) and in a progressive ratio schedule (-81 percent). NAC also reduced ethanol-seeking behavior (-77 percent) evaluated as extinction responding in a single extinction session. NAC was able to reduce reacquisition in rats that were abstinent for 17 days, while NAC had no effect on ethanol relapse in rats previously exposed to six extinction sessions. Overall, our results demonstrate that NAC limits motivation, seeking behavior and reacquisition in rats, making it a potential new treatment for the maintenance of abstinence.

Frailty in severe COVID-19 survivors after ICU admission. A prospective and multicenter study in Mexico.

OBJECTIVE: To analyze the presence of frailty in survivors of severe COVID-19 admitted in the Intensive Care Unit (ICU) and followed six months after discharge. DESIGN: An observational, prospective and multicenter, nation-wide study. SETTING: Eight adult ICU across eight academic acute care hospitals in Mexico. PATIENTS: All consecutive adult COVID-19 patients admitted in the ICU with acute respiratory failure between March 8, 2020 to February 28, 2021 were included. Frailty was defined according to the FRAIL scale, and was obtained at ICU admission and 6-month after hospital discharge. INTERVENTIONS: None. MAIN VARIABLES OF INTEREST: The primary endpoint was the frailty status 6-months after discharge. A regression model was used to evaluate the predictors during ICU stay associated with frailty. RESULTS: 196 ICU survivors were evaluated for basal frailty at ICU admission and were included in this analysis. After 6-months from discharge, 164 patients were evaluated for frailty: 40 patients (20.4%) were classified as non-frail, 67 patients (34.2%) as pre-frail and 57 patients (29.1%) as frail. After adjustment, the need of invasive mechanical ventilation was the only factor independently associated with frailty at 6 month follow-up (Odds Ratio [OR] 3.70, 95% confidence interval 1.40-9.81, P = .008). CONCLUSIONS: Deterioration of frailty was reported frequently among ICU survivors with severe COVID-19 at 6-months. The need of invasive mechanical ventilation in ICU survivors was the only predictor independently associated with frailty.

Chemosensitivity linked to p73 function.

Most chemotherapeutic agents induce DNA damage, leading to p53 accumulation and apoptosis. The factors that determine chemosensitivity in p53-defective tumor cells are poorly understood. We found that the p53 family member p73 is induced by a wide variety of chemotherapeutic drugs. Blocking p73 function with a dominant-negative mutant, siRNA, or homologous recombination led to chemoresistance of human tumor cells and engineered transformed cells, irrespective of p53 status. Mutant p53 can inactivate p73 and downregulation of mutant p53 enhanced chemosensitivity. These findings indicate that p73 is a determinant of chemotherapeutic efficacy in humans.

Evaluation of N-acetylcysteine on ethanol self-administration in ethanol-dependent rats.

Many components of ethanol addiction such as reinforcement, withdrawal, extinction, and relapse are known to involve glutamate transmission. NAC could counteract glutamatergic dysregulation underlying ethanol addiction. We previously demonstrated the efficacy of N-acetylcysteine (NAC) treatment to reduce ethanol consumption, motivation, seeking, and relapse in rats displaying a binge drinking-like phenotype. The current study assessed whether acute NAC could reduce ethanol self-administration, ethanol-seeking behavior, motivation, and reacquisition of ethanol self-administration following abstinence in ethanol-dependent rats. Ethanol dependence was induced by chronic intermittent ethanol (CIE) vapor exposure for 10 weeks in male Wistar rats. Effects of NAC (0, 25, 50 or 100 mg/kg; i.p.) were evaluated during acute withdrawal, 8 h after inhalation chambers were turned off. We evaluated NAC effect on the expression of the xCT protein expression (the target of NAC) and glutamate transporters (GLT-1) in dependent rats. We showed that in dependent rats, the low dose of NAC (25 mg/kg) reduced ethanol self-administration and motivation to consume ethanol, evaluated in a progressive ratio paradigm. At 50 mg/kg, but not 25 mg/kg, NAC reduced extinction responding and reacquisition of self-administration after 1 month abstinence. The xCT protein expression was decreased in the nucleus accumbens in dependent compared with ethanol-naïve rats. Thus, NAC may be effective by decreasing glutamate transmission through presynaptic mechanisms (i.e. the stimulation of xc--mediated increase in extrasynaptic glutamate levels). Our results demonstrate that NAC decreased ethanol self-administration, extinction responding, and relapse in ethanol-dependent animals, and thus strongly support clinical development of NAC for alcohol use disorders.

Gasping generation in developing Swiss-Webster mice in vitro and in vivo.

During hypoxia the respiratory network produces gasping in vivo and in vitro. To understand the mechanisms involved in such response and to validate in vitro findings, correlative studies are necessary. During perinatal age gasping generation is robust and then declines during postnatal development, possibly due to changes in either the rhythm generator (the pre-Bötzinger complex, PBC) and/or its motor outputs. We tested this hypothesis by recording respiratory response to hypoxia in vivo and in vitro during postnatal development. We found that postnatal age influences: (1) The hypoxia-induced pattern change in the PBC bursts, (2) The coupling between the PBC and the XII nucleus during prolonged hypoxia and (3) The ability of mice to gasp and autoresuscitate from hypoxic conditions. We conclude that the inability of mice to gasp during late postnatal development might be determined by a progressive uncoupling between the respiratory rhythm generator and its motor outputs in hypoxia.

Evaluation of alcohol use disorders pharmacotherapies in a new preclinical model of binge drinking.

Binge drinking is defined as a pattern of drinking leading to intoxication in a single short session and is a serious but preventable public health problem. Only few animal models of voluntary binge drinking using an operant paradigm are available in outbred animals and in general they do not display good face validity. We recently set up a new model of binge drinking behavior using an operant self-administration paradigm in which rats drink to intoxication level in 15-min daily session. Here we tested the current pharmacotherapies of alcohol use disorder: Acamprosate, (R)-Baclofen, gamma-hydroxybutyric acid, Nalmefene and Naltrexone. Our results show that all drugs are effective in reducing ethanol drinking. All drugs except Acamprosate also reduced the motivational properties of ethanol (breakpoint). (R)-Baclofen and gamma-hydroxybutyric acid were effective on ethanol intake at doses devoid of side effects. Among the tested drugs only (R)-Baclofen, gamma-hydroxybutyric acid and Naltrexone reduced reacquisition after a period of abstinence. Interestingly, the efficacy of all drugs except Nalmefene to reduce ethanol drinking was slightly and positively correlated with the basal level of drinking thus revealing heavy drinking as a predictive factor. In summary, all current alcohol use disorder pharmacotherapies were effective in our model of binge drinking behavior thus bringing new data regarding its good predictive validity. The tested drugs display some specificity regarding their effect on motivation, reacquisition and also in terms of individual factors such as basal drinking level. Our new model opens promising perspectives about the development of pharmacotherapies targeting binge drinking behavior.

Acute Kidney Injury in Mechanically Ventilated Patients: The Risk Factor Profile Depends on the Timing of Aki Onset.

BACKGROUND: Acute kidney injury (AKI) is a frequent complication in patients under mechanical ventilation (MV). We aimed to assess the risk factors for AKI with particular emphasis on those potentially preventable. STUDY DESIGN, SETTING, AND PARTICIPANTS: Retrospective analysis of a large, multinational database of MV patients with >24 h of MV and normal renal function at admission. AKI was defined according to creatinine-based KDIGO criteria. Risk factors were analyzed according to the time point at which AKI occurred: early (≤48 h after ICU admission, AKIE) and late (day 3 to day 7 of ICU stay, AKIL). A conditional logistic regression model was used to identify variables independently associated with AKI. RESULTS: Three thousand two hundred six patients were included. Seven hundred patients had AKI (22%), the majority of them AKIE (547/704). The risk factor profile was highly dependent upon the timing of AKI onset. In AKIE risk factors were older age; SAPS II score; postoperative and cardiac arrest as the reasons for MV; worse cardiovascular SOFA, pH, serum creatinine, and platelet count; higher level of peak pressure and Vt/kg; and fluid overload at admission. In contrast, AKIL was linked mostly to events that occurred after admission (lower platelet count and pH; ICU-acquired sepsis; and fluid overload). None ventilation-associated parameters were identify as risk factors for AKIL. CONCLUSIONS: In the first 48 h, risk factors are associated with the primary disease and the patient's condition at admission. Subsequently, emergent events like sepsis and organ dysfunction appear to be predictive factors making prevention a challenge.

Hypoxia-inducible TAp73 supports tumorigenesis by regulating the angiogenic transcriptome.

The functional significance of the overexpression of unmutated TAp73, a homologue of the tumour suppressor p53, in multiple human cancers is unclear, but raises the possibility of unidentified roles in promoting tumorigenesis. We show here that TAp73 is stabilized by hypoxia, a condition highly prevalent in tumours, through HIF-1α-mediated repression of the ubiquitin ligase Siah1, which targets TAp73 for degradation. Consequently, TAp73-deficient tumours are less vascular and reduced in size, and conversely, TAp73 overexpression leads to increased vasculature. Moreover, we show that TAp73 is a critical regulator of the angiogenic transcriptome and is sufficient to directly activate the expression of several angiogenic genes.  Finally, expression of TAp73 positively correlates with these angiogenic genes in several human tumours, and the angiogenic gene signature is sufficient to segregate the TAp73(Hi)- from TAp73(Low)-expressing tumours. These data demonstrate a pro-angiogenic role for TAp73 in supporting tumorigenesis, providing a rationale for its overexpression in cancers.

Involvement of endogenous salicylic acid content, lipoxygenase and antioxidant enzyme activities in the response of tomato cell suspension cultures to NaCl.

• The effects of salt stress and adaptation on salicylic acid (SA) content and on antioxidant and lipoxygenase (LOX) enzyme activities were studied in tomato (Lycopersicon esculentum cv. Pera) cells. • NaCl-adapted cells were obtained from calli adapted to 100 mm NaCl by successive subcultures in medium supplemented with 100 mm NaCl. Salt stress treatments consisted of the addition of 100 mm NaCl to cells. • Adapted cells contained a lower concentration of SA than unadapted cells. The lower manganese-containing superoxide dismutase (Mn-SOD) and LOX activities as well as the higher glutathione reductase (GR) and ascorbate peroxidase (APX) activities in adapted cells than in unadapted cells could be correlated with the development of salt adaptation. Salt stress increased APX and LOX activities as well as lipid peroxidation in unadapted cells and increased Mn-SOD activity in both types of cells. Application of 200 µm SA + 100 mm NaCl inhibited APX activity in both unadapted and adapted cells, induced the Mn-SOD in adapted cells and increased lipid peroxidation in unadapted cells. • Our data indicate that adaptation of tomato cells to NaCl results in a higher tolerance to NaCl-induced oxidative stress and suggest a role for SA in this response.