Risk factors for deliberate self-poisoning among children and adolescents in The Netherlands.

INTRODUCTION: In the past decade, the number of deliberate self-poisonings involving young people has increased strongly worldwide. This study aimed to gain insight into risk factors associated with deliberate self-poisonings among children and adolescents reported to the Dutch Poisons Information Center. METHODS: A study was performed between 1 February 2022 and 31 January 2023 involving those aged 8-17 years of age with deliberate self-poisoning. Data were collected on patient characteristics (age, gender, body mass index and living situation) and exposure characteristics (type of toxicant, way of acquiring toxicant and day of exposure). RESULTS: The Dutch Poisons Information Center was consulted about 1,424 deliberate self-poisonings among children and adolescents (10-17 years old). A high percentage of patients were female (85 percent), had a body mass index classified as overweight/obese (27 percent) and lived in a mental healthcare facility (13 percent). Patients mainly exposed themselves to pharmaceuticals, especially over-the-counter medications such as paracetamol (46 percent) and ibuprofen (15 percent). Young people living with parents/caregivers had higher odds of ingesting prescription pharmaceuticals or over-the-counter medication, while those living in a mental healthcare facility were more likely to ingest household products, personal care products or foreign bodies (predominantly batteries). DISCUSSION: This study sheds light on the pervasive issue of deliberate self-poisoning among children and adolescents, advocating for poisoning prevention strategies and promoting mental health of youth. Limitations include reliance on self-reported data from patients and the absence of clinical outcome data. CONCLUSIONS: Female gender, a high body mass index and living in a mental healthcare facility are associated with in increased risk of deliberate self-poisonings in children and adolescents (10-17 years old). Prevention of deliberate self-poisonings among youth could focus on restricting access to medication and other potentially hazardous non-pharmaceuticals, such as household products and batteries, as well as limiting the sales of over-the-counter medication, especially paracetamol, to this young population.

Significant Increase in Deliberate Self-Poisonings Among Adolescents During the Second Year of the COVID-19 Pandemic.

PURPOSE: The COVID-19 pandemic has been associated with a decline in mental health of adolescents. The aim of this study was to analyze the rate of deliberate self-poisonings (DSPs) among adolescents reported to the Dutch Poisons Information Center before and during the COVID-19 pandemic. METHODS: A retrospective study from 2016 until 2021 was performed to characterize DSPs among adolescents, and to analyze trends in the number of DSPs. All DSPs among adolescents with the age of 13 up to and including 17 years were included. DSP characteristics included: age, gender, bodyweight, used substance, dose, and treatment advice. Trends in the number of DSPs were analyzed using time series decomposition and Seasonal Autoregressive Integrated Moving Average models. RESULTS: Six thousand nine hundred fifteen DSPs in adolescents were recorded from January first 2016 until December 31st 2021. Females were involved in 84% of adolescent DSPs. A strong increase in the number of DSPs was observed in 2021 (45% increase compared to 2020), which deviated from the predicted trend based on previous years. This increase was most prominent in 13-, 14-, and 15-year-old female adolescents. Commonly involved drugs were paracetamol, ibuprofen, methylphenidate, fluoxetine, and quetiapine. The contribution of paracetamol rose from 33% in 2019 to 40% in 2021. DISCUSSION: The strong increase in the number of DSPs during the second year of the COVID-19 pandemic suggests that long-term containment measures such as quarantines, lockdowns, and school closures may enhance self-harm behavior among adolescents, especially among younger females (13-15 years of age), with a preference for paracetamol as DSP substance.

PPARγ lipodystrophy mutants reveal intermolecular interactions required for enhancer activation.

Peroxisome proliferator-activated receptor γ (PPARγ) is the master regulator of adipocyte differentiation, and mutations that interfere with its function cause lipodystrophy. PPARγ is a highly modular protein, and structural studies indicate that PPARγ domains engage in several intra- and inter-molecular interactions. How these interactions modulate PPARγ's ability to activate target genes in a cellular context is currently poorly understood. Here we take advantage of two previously uncharacterized lipodystrophy mutations, R212Q and E379K, that are predicted to interfere with the interaction of the hinge of PPARγ with DNA and with the interaction of PPARγ ligand binding domain (LBD) with the DNA-binding domain (DBD) of the retinoid X receptor, respectively. Using biochemical and genome-wide approaches we show that these mutations impair PPARγ function on an overlapping subset of target enhancers. The hinge region-DNA interaction appears mostly important for binding and remodelling of target enhancers in inaccessible chromatin, whereas the PPARγ-LBD:RXR-DBD interface stabilizes the PPARγ:RXR:DNA ternary complex. Our data demonstrate how in-depth analyses of lipodystrophy mutants can unravel molecular mechanisms of PPARγ function.

Clinical toxicology of exposures to chemicals from clandestine drug laboratories: a literature review.

INTRODUCTION: The synthesis of clandestine drugs is a widespread worldwide phenomenon, with clandestine drug laboratories occurring both in rural and urban areas. There is considerable unfamiliarity among medical professionals about the health risks that are associated with chemicals used in clandestine drug laboratories. OBJECTIVE: To evaluate the adverse health effects resulting from exposure to chemicals involved in the production of clandestine drugs. METHODS: The US National Library of Medicine PubMed database and the Excerpta Medica database (EMBASE) were searched from their date of inception to October 26, 2021 using combinations of relevant search terms. This yielded 1,558 unique articles, which were subjected to two eligibility criteria: (i) exposure to clandestine drug laboratory chemicals resulting in adverse health effects; (ii) subjects were human. A total of 22 unique articles were retrieved, consisting of 10 reviews, eight case reports/series and four retrospective studies. Further searches among the references cited in these publications yielded another seven case reports/series and six retrospective studies. RESULTS: Inhalation: Surveillance studies reported respiratory symptoms (including cough, throat irritation, nasal irritation, and dyspnea) in 59% (n = 1,657 of 2,803) of those exposed. The case reports/series described respiratory symptoms in 43% of the cases (n = 36 of 84). Lung edema was reported occasionally (n = 2). Eye exposure: Surveillance studies reported eye irritation and burns in 23% (n = 647 of 2,803) of those exposed. The case reports/series described ocular adverse events in 36% of the cases (n = 30 of 84). More severe ocular effects, such as corneal damage and conjunctival necrosis, were reported after direct eye contact with caustic fluids. Skin exposure: Surveillance studies reported dermal effects, ranging from skin irritation to severe burns, in 6% of those exposed (n = 174 of 2,803). The case reports/series described dermal effects in 30% of the cases (n = 25 of 84). Ingestion: Gastrointestinal burns were observed after ingestion of caustic substances in 5% of the patients reported in the case reports/series (n = 4 of 84). Systemic effects: Surveillance studies reported headache and dizziness in 31% (n = 882 of 2,803) and 7% (n = 187 of 2,803) of those exposed, respectively. The case reports/series described sympathomimetic effects, including mydriasis, hypertension, tachycardia, in 4% of the cases (n = 3 of 84). Fatalities: Surveillance studies reported death in 1% of those exposed (n = 29 of 2803). Ten percent of the people reported in the cases report/series died (n = 8 of 84). Death was reported after inhalation of phosphine (n = 5), hydrogen sulfide (n = 1), methanol (n = 1), and after ingestion of sulfuric acid (n = 1). CONCLUSIONS: Exposure to chemicals involved in the production of clandestine drugs mostly resulted in mild to moderate respiratory, ocular or dermal effects, usually caused by caustic chemicals or solvents. Systemic effects were generally mild, but severe symptoms and eight deaths were reported after exposure to phosphine, hydrogen sulfide, methanol and sulfuric acid.

Estimation of the risk of local and systemic effects in infants after ingestion of low-concentrated weak acids from descaling products.

INTRODUCTION: The accidental ingestion of diluted household descaling products by infants is a phenomenon that poison control centers regularly encounter. Feeding infants with baby milk prepared with water from electric kettles still containing descaler is a common way of exposure. This study aimed to determine the risks related to ingestion of (diluted) descalers by infants. METHODS: pH measurements were performed using acetic acid and three different commercially available electric kettle descalers. The pH of different dilutions was measured in the absence or presence of baby milk powder. In addition, an overview was made of pH values of different electric kettle descalers as given by the product information of the manufacturer. Finally, a simple pharmacokinetic (PK) model was used to predict changes in blood pH in infants after ingestion of acetic acid, which is the most commonly used descaler. RESULTS: Several commercially available electric kettle descalers have a pH <2. Even after diluting such descalers up to 10 times the pH can remain low. The addition of milk powder increases the pH of descalers containing weaker acids, with a pH >1.5, while descalers with stronger acids and pH <1 show little pH increase after the addition of milk powder. Finally, a simple PBPK model for the ingestion of acetic acid predicted that the ingestion of larger amounts of acetic acid (>1000 mg) by an infant could result in relevant changes in blood pH. CONCLUSIONS: Commercially available electric kettle descaling products may pose a health risk to infants in case of accidental ingestion since the pH of some of these products can be very low, even when diluted 10-times or in the presence of baby milk powder. Oral exposure of infants to the common descaler acetic acid, after accidental preparation of baby milk with cleaning vinegar, will probably not result in serious local effects, but changes in blood pH cannot be excluded when larger amounts of acetic acid are ingested.

Profiling of 3696 Nuclear Receptor-Coregulator Interactions: A Resource for Biological and Clinical Discovery.

Nuclear receptors (NRs) are ligand-inducible transcription factors that play critical roles in metazoan development, reproduction, and physiology and therefore are implicated in a broad range of pathologies. The transcriptional activity of NRs critically depends on their interaction(s) with transcriptional coregulator proteins, including coactivators and corepressors. Short leucine-rich peptide motifs in these proteins (LxxLL in coactivators and LxxxIxxxL in corepressors) are essential and sufficient for NR binding. With 350 different coregulator proteins identified to date and with many coregulators containing multiple interaction motifs, an enormous combinatorial potential is present for selective NR-mediated gene regulation. However, NR-coregulator interactions have often been determined experimentally on a one-to-one basis across diverse experimental conditions. In addition, NR-coregulator interactions are difficult to predict because the molecular determinants that govern specificity are not well established. Therefore, many biologically and clinically relevant NR-coregulator interactions may remain to be discovered. Here, we present a comprehensive overview of 3696 NR-coregulator interactions by systematically characterizing the binding of 24 nuclear receptors with 154 coregulator peptides. We identified unique ligand-dependent NR-coregulator interaction profiles for each NR, confirming many well-established NR-coregulator interactions. Hierarchical clustering based on the NR-coregulator interaction profiles largely recapitulates the classification of NR subfamilies based on the primary amino acid sequences of the ligand-binding domains, indicating that amino acid sequence is an important, although not the only, molecular determinant in directing and fine-tuning NR-coregulator interactions. This NR-coregulator peptide interactome provides an open data resource for future biological and clinical discovery as well as NR-based drug design.

The relation between body iron stores and adipose tissue function in patients with manifest vascular disease.

BACKGROUND: We investigated whether plasma ferritin levels through the pro-inflammatory effects of free iron are associated with adipose tissue dysfunction in a relevant population of patients with manifest vascular disease who would potentially benefit the most from further aetiological insights. MATERIALS AND METHODS: In a cohort of 355 patients with vascular diseases, the association between plasma ferritin and adiponectin levels was quantified using linear regression analysis. Interleukin-6 and adiponectin levels were measured in medium from pre-adipocytes and adipocytes after incubation with increasing concentrations of Fe(III)-citrate and after co-incubation with iron chelators or radical scavengers. RESULTS: Increasing ferritin plasma concentrations were not related to plasma adiponectin levels in patients without (ß -0·13; 95% CI -0·30 to 0·04) or with the metabolic syndrome (ß -0·04; 95% CI -0·17 to 0·10). Similar results were found in patients who developed a new cardiovascular event in the follow-up period. In vitro, incubation with increasing concentrations of Fe(III)-citrate-induced inflammation in pre-adipocyte cultures as witnessed by increased IL-6 secretion at 30 µm Fe(III)-citrate vs. control (500 ± 98 pg/mL vs. 194 ± 31 pg/mL, P = 0·03). Co-incubation of pre-adipocytes with iron chelators or radical scavengers prevented this inflammatory response. Incubation of adipocytes with 30 µm Fe(III)-citrate did not influence adiponectin secretion compared with control. CONCLUSIONS: In patients with vascular disease, there is no association between plasma ferritin and adiponectin levels. In vitro, free iron induces an inflammatory response in pre-adipocytes, but not in adipocytes. This response was blocked by co-incubation with iron chelators or radical scavengers. Adiponectin secretion by adipocytes was not influenced by free iron.

Early adipogenesis is regulated through USP7-mediated deubiquitination of the histone acetyltransferase TIP60.

Transcriptional coregulators, including the acetyltransferase Tip60, have a key role in complex cellular processes such as differentiation. Whereas post-translational modifications have emerged as an important mechanism to regulate transcriptional coregulator activity, the identification of the corresponding demodifying enzymes has remained elusive. Here we show that the expression of the Tip60 protein, which is essential for adipocyte differentiation, is regulated through polyubiquitination on multiple residues. USP7, a dominant deubiquitinating enzyme in 3T3-L1 adipocytes and mouse adipose tissue, deubiquitinates Tip60 both in intact cells and in vitro and increases Tip60 protein levels. Furthermore, inhibition of USP7 expression and activity decreases adipogenesis. Transcriptome analysis reveals several cell cycle genes to be co-regulated by both Tip60 and USP7. Knockdown of either factor results in impaired mitotic clonal expansion, an early step in adipogenesis. These results reveal deubiquitination of a transcriptional coregulator to be a key mechanism in the regulation of early adipogenesis.

Pmch-deficiency in rats is associated with normal adipocyte differentiation and lower sympathetic adipose drive.

The orexigenic neuropeptide melanin-concentrating hormone (MCH), a product of Pmch, is an important mediator of energy homeostasis. Pmch-deficient rodents are lean and smaller, characterized by lower food intake, body-, and fat mass. Pmch is expressed in hypothalamic neurons that ultimately are components in the sympathetic nervous system (SNS) drive to white and interscapular brown adipose tissue (WAT, iBAT, respectively). MCH binds to MCH receptor 1 (MCH1R), which is present on adipocytes. Currently it is unknown if Pmch-ablation changes adipocyte differentiation or sympathetic adipose drive. Using Pmch-deficient and wild-type rats on a standard low-fat diet, we analyzed dorsal subcutaneous and perirenal WAT mass and adipocyte morphology (size and number) throughout development, and indices of sympathetic activation in WAT and iBAT during adulthood. Moreover, using an in vitro approach we investigated the ability of MCH to modulate 3T3-L1 adipocyte differentiation. Pmch-deficiency decreased dorsal subcutaneous and perirenal WAT mass by reducing adipocyte size, but not number. In line with this, in vitro 3T3-L1 adipocyte differentiation was unaffected by MCH. Finally, adult Pmch-deficient rats had lower norepinephrine turnover (an index of sympathetic adipose drive) in WAT and iBAT than wild-type rats. Collectively, our data indicate that MCH/MCH1R-pathway does not modify adipocyte differentiation, whereas Pmch-deficiency in laboratory rats lowers adiposity throughout development and sympathetic adipose drive during adulthood.

The serine/threonine phosphatase PPM1B (PP2Cß) selectively modulates PPARγ activity.

Reversible phosphorylation is a widespread molecular mechanism to regulate the function of cellular proteins, including transcription factors. Phosphorylation of the nuclear receptor PPARγ (peroxisome-proliferator-activated receptor γ) at two conserved serine residue (Ser(112) and Ser(273)) results in an altered transcriptional activity of this transcription factor. So far, only a very limited number of cellular enzymatic activities has been described which can dephosphorylate nuclear receptors. In the present study we used immunoprecipitation assays coupled to tandem MS analysis to identify novel PPARγ-regulating proteins. We identified the serine/threonine phosphatase PPM1B [PP (protein phosphatase), Mg(2+)/Mn(2+) dependent, 1B; also known as PP2Cß] as a novel PPARγ-interacting protein. Endogenous PPM1B protein is localized in the nucleus of mature 3T3-L1 adipocytes where it can bind to PPARγ. Furthermore we show that PPM1B can directly dephosphorylate PPARγ, both in intact cells and in vitro. In addition PPM1B increases PPARγ-mediated transcription via dephosphorylation of Ser(112). Finally, we show that knockdown of PPM1B in 3T3-L1 adipocytes blunts the expression of some PPARγ target genes while leaving others unaltered. These findings qualify the phosphatase PPM1B as a novel selective modulator of PPARγ activity.

Short-chain fatty acids stimulate angiopoietin-like 4 synthesis in human colon adenocarcinoma cells by activating peroxisome proliferator-activated receptor γ.

Angiopoietin-like protein 4 (ANGPTL4/FIAF) has been proposed as a circulating mediator between the gut microbiota and fat storage. Here, we show that transcription and secretion of ANGPTL4 in human T84 and HT29 colon adenocarcinoma cells is highly induced by physiological concentrations of short-chain fatty acids (SCFA). SCFA induce ANGPTL4 by activating the nuclear receptor peroxisome proliferator activated receptor γ (PPARγ), as demonstrated using PPARγ antagonist, PPARγ knockdown, and transactivation assays, which show activation of PPARγ but not PPARα and PPARδ by SCFA. At concentrations required for PPARγ activation and ANGPTL4 induction in colon adenocarcinoma cells, SCFA do not stimulate PPARγ in mouse 3T3-L1 and human SGBS adipocytes, suggesting that SCFA act as selective PPARγ modulators (SPPARM), which is supported by coactivator peptide recruitment assay and structural modeling. Consistent with the notion that fermentation leads to PPAR activation in vivo, feeding mice a diet rich in inulin induced PPAR target genes and pathways in the colon. We conclude that (i) SCFA potently stimulate ANGPTL4 synthesis in human colon adenocarcinoma cells and (ii) SCFA transactivate and bind to PPARγ. Our data point to activation of PPARs as a novel mechanism of gene regulation by SCFA in the colon, in addition to other mechanisms of action of SCFA.

Natural killer T cells in adipose tissue prevent insulin resistance.

Lipid overload and adipocyte dysfunction are key to the development of insulin resistance and can be induced by a high-fat diet. CD1d-restricted invariant natural killer T (iNKT) cells have been proposed as mediators between lipid overload and insulin resistance, but recent studies found decreased iNKT cell numbers and marginal effects of iNKT cell depletion on insulin resistance under high-fat diet conditions. Here, we focused on the role of iNKT cells under normal conditions. We showed that iNKT cell-deficient mice on a low-fat diet, considered a normal diet for mice, displayed a distinctive insulin resistance phenotype without overt adipose tissue inflammation. Insulin resistance was characterized by adipocyte dysfunction, including adipocyte hypertrophy, increased leptin, and decreased adiponectin levels. The lack of liver abnormalities in CD1d-null mice together with the enrichment of CD1d-restricted iNKT cells in both mouse and human adipose tissue indicated a specific role for adipose tissue-resident iNKT cells in the development of insulin resistance. Strikingly, iNKT cell function was directly modulated by adipocytes, which acted as lipid antigen-presenting cells in a CD1d-mediated fashion. Based on these findings, we propose that, especially under low-fat diet conditions, adipose tissue-resident iNKT cells maintain healthy adipose tissue through direct interplay with adipocytes and prevent insulin resistance.

A novel RNAi lethality rescue screen to identify regulators of adipogenesis.

Adipogenesis, the differentiation of fibroblast-like mesenchymal stem cells into mature adipocytes, is tightly regulated by a complex cascade of transcription factors, including the nuclear receptor Peroxisome proliferator activator receptor γ (PPARγ). RNAi-mediated knock down libraries may present an attractive method for the identification of additional adipogenic factors. However, using in vitro adipogenesis model systems for high-throughput screening with siRNA libraries is limited since (i) differentiation is not homogeneous, but results in mixed cell populations, and (ii) the expression levels (and activity) of adipogenic regulators is highly dynamic during differentiation, indicating that the timing of RNAi-mediated knock down during differentiation may be extremely critical. Here we report a proof-of-principle for a novel RNAi screening method to identify regulators of adipogenesis that is based on lethality rescue rather than differentiation, using microRNA expression driven by a PPARγ responsive RNA polymerase II promoter. We validated this novel method through screening of a dedicated deubiquitinase knock down library, resulting in the identification of UCHL3 as an essential deubiquitinase in adipogenesis. This system therefore enables the identification of novel genes regulating PPARγ-mediated adipogenesis in a high-throughput setting.

Pref-1 preferentially inhibits heat production in brown adipose tissue.

In mammals there are two types of adipocytes with opposing functions. Brown adipocytes are characterized by a high number of mitochondria and are specialized for heat production (thermogenesis), expressing thermogenic genes such as UCP1 (uncoupling protein 1). White adipocytes, on the other hand, store energy. Although many key regulators in the differentiation of white adipocytes have been established, our current knowledge on the same proteins in brown adipogenesis is lagging behind. One example is Pref-1 (pre-adipocyte factor-1), which maintains white pre-adipocytes in an undifferentiated state, but is only poorly characterized in the brown pre-adipocyte lineage. In this issue of the Biochemical Journal, Armengol et al. now shed new light on the role and regulation of Pref-1 in brown pre-adipocytes. First, Pref-1 specifically inhibits the thermogenic gene programme in brown pre-adipocytes. Secondly, they identified the transcription factor C/EBPδ (CCAAT/enhancer-binding protein δ) as a direct positive regulator of Pref-1 expression, whereas this protein does not fulfil this role in white adipogenesis. Taken together, these findings indicate that specific manipulation of brown adipocyte differentiation and/or function without interfering with their white adipocyte counterparts may be possible, which may open up new therapeutic ways to combat obesity-associated health problems.

Brown vs white adipocytes: the PPARgamma coregulator story.

The development of adipose tissue is a process which involves the concerted cooperation of numerous transcription factors together with their coactivators and corepressors. The peroxisome proliferator-activated receptor gamma (PPARgamma) is considered to be one of the master regulators of adipocyte differentiation. The presence of two functionally distinct types of adipose tissue, white and brown (WAT and BAT), requires an even more complex regulation of adipose tissue development. In this review we will focus on the role of PPARgamma coregulators in adipogenesis and especially on the role of PPARgamma coregulators in white and brown adipose tissue. Specificity in coregulator function in WAT and BAT may form an additional level of regulation of adipose tissue development.

Epidermis-type lipoxygenase 3 regulates adipocyte differentiation and peroxisome proliferator-activated receptor gamma activity.

The nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR gamma) is essential for adipogenesis. Although several fatty acids and their derivatives are known to bind and activate PPAR gamma, the nature of the endogenous ligand(s) promoting the early stages of adipocyte differentiation has remained enigmatic. Previously, we showed that lipoxygenase (LOX) activity is involved in activation of PPAR gamma during the early stages of adipocyte differentiation. Of the seven known murine LOXs, only the unconventional LOX epidermis-type lipoxygenase 3 (eLOX3) is expressed in 3T3-L1 preadipocytes. Here, we show that forced expression of eLOX3 or addition of eLOX3 products stimulated adipogenesis under conditions that normally require an exogenous PPAR gamma ligand for differentiation. Hepoxilins, a group of oxidized arachidonic acid derivatives produced by eLOX3, bound to and activated PPAR gamma. Production of hepoxilins was increased transiently during the initial stages of adipogenesis. Furthermore, small interfering RNA-mediated or retroviral short hairpin RNA-mediated knockdown of eLOX3 expression abolished differentiation of 3T3-L1 preadipocytes. Finally, we demonstrate that xanthine oxidoreductase (XOR) and eLOX3 synergistically enhanced PPAR gamma-mediated transactivation. Collectively, our results indicate that hepoxilins produced by the concerted action of XOR and eLOX3 may function as PPAR gamma activators capable of promoting the early PPAR gamma-dependent steps in the conversion of preadipocytes into adipocytes.