Dihydroxyacetone suppresses mTOR nutrient signaling and induces mitochondrial stress in liver cells.

Dihydroxyacetone (DHA) is the active ingredient in sunless tanning products and a combustion product from e-juices in electronic cigarettes (e-cigarettes). DHA is rapidly absorbed in cells and tissues and incorporated into several metabolic pathways through its conversion to dihydroxyacetone phosphate (DHAP). Previous studies have shown DHA induces cell cycle arrest, reactive oxygen species, and mitochondrial dysfunction, though the extent of these effects is highly cell-type specific. Here, we investigate DHA exposure effects in the metabolically active, HepG3 (C3A) cell line. Metabolic and mitochondrial changes were evaluated by characterizing the effects of DHA in metabolic pathways and nutrient-sensing mechanisms through mTOR-specific signaling. We also examined cytotoxicity and investigated the cell death mechanism induced by DHA exposure in HepG3 cells. Millimolar doses of DHA were cytotoxic and suppressed glycolysis and oxidative phosphorylation pathways. Nutrient sensing through mTOR was altered at both short and long time points. Increased mitochondrial reactive oxygen species (ROS) and mitochondrial-specific injury induced cell cycle arrest and cell death through a non-classical apoptotic mechanism. Despite its carbohydrate nature, millimolar doses of DHA are toxic to liver cells and may pose a significant health risk when higher concentrations are absorbed through e-cigarettes or spray tanning.

Does intensive interdisciplinary pain treatment improve pediatric headache-related disability?

PURPOSE: To examine the effectiveness of intensive interdisciplinary pain treatment for improving disability in children with chronic headache using the International Classification of Functioning, Disability and Health model as a conceptual framework for disability assessment. MATERIALS AND METHODS: Children with chronic headache (n = 50; ages 10-19 years; 62% female) attended an intensive interdisciplinary pain treatment program 8 h/day, 5 times/week for 2-7 weeks. Disability measures were administered at admission, discharge, and 6-8 week follow-up. Disability outcomes were analyzed retrospectively. Wilcoxon signed rank tests and Friedman's analyses of variance were used to compare scores across two and three longitudinal time points, respectively. RESULTS: After rehabilitation, disability reduced on the Headache Impact Test-6 from severe impact at admission to some impact at follow-up (p < 0.001). Median time on the modified Bruce protocol increased from 13.1 min (interquartile range = 12.6-14.1) to 14.4 min (interquartile range = 12.9-16.3), p < 0.001, with gains maintained at follow-up. Improvements in pain and disability were associated with improvements in school participation. CONCLUSIONS: Findings of this study support the effectiveness of intensive interdisciplinary pain treatment for improving disability in children with chronic headache.Implication for rehabilitationIntensive interdisciplinary pain treatment is effective for improving pain and disability in children with chronic headaches.Application of the ICF model to disability assessment suggests that children with chronic headaches may experience significant disability, even when standardized assessments of physical capacity are normal.The modified Bruce protocol, Pediatric Evaluation of Disability Inventory - Computerized Adaptive Tests, and Headache Impact Test-6 appear particularly valuable in understanding the nature of disability in children with chronic headaches.

Under Pressure to Perform: Impact of Academic Goal Orientation, School Motivational Climate, and School Engagement on Pain and Somatic Symptoms in Adolescents.

OBJECTIVES: Various academic factors are known to influence pain and somatic symptoms in adolescents, but the roles of academic goal orientation, school motivational climate, and school engagement are unknown. This study examined how these understudied academic factors are associated with adolescent pain and somatic symptoms and whether sex moderates the relations. MATERIALS AND METHODS: High school students (n=90) from a high-achieving community completed questionnaires assessing academic variables, various pain characteristics, and somatic symptoms. RESULTS: The majority of adolescents (67%) experienced pain and somatic symptoms in the past month, with 56% reporting multisite pain and 58% reporting at least 1 severe somatic symptom. Headache and abdominal pain were the most frequently reported "most bothersome" pains, and pain was rated, on average, as moderately severe, typically occurring several times per month, and was primarily chronic in nature (duration, ≥3 mo). Higher levels of ego goal orientation and perceived performance motivational climate were associated with more somatic symptoms, and ego goal orientation was also associated with more intense and frequent pain. Alternatively, greater school engagement was associated with fewer somatic symptoms. Task goal orientation and mastery motivational climate were unassociated with all pain and somatic symptom outcomes. DISCUSSION: This study demonstrates that adolescents from a high-achieving community report more somatic symptoms and pain when they are less engaged in school and when their academic focus is on grades and outperforming peers. Results suggest that de-emphasizing competition and performance outcomes may support physical well-being in adolescents.

Dihydroxyacetone Exposure Alters NAD(P)H and Induces Mitochondrial Stress and Autophagy in HEK293T Cells.

Dihydroxyacetone phosphate (DHAP) is the endogenous byproduct of fructose metabolism. Excess DHAP in cells can induce advanced glycation end products and oxidative stress. Dihydroxyacetone (DHA) is the triose precursor to DHAP. DHA is used as the active ingredient in sunless tanning products, including aerosolized spray tans, and is formed by the combustion of solvents found in electronic cigarettes. Human exposure to DHA has been increasing as the popularity of sunless tanning products and electronic cigarettes has grown. Topically applied DHA is absorbed through the viable layers of the skin and into the bloodstream. Exogenous exposure to DHA is cytotoxic in immortalized keratinocytes and melanoma cells with cell cycle arrest induced within 24 h and cell death occurring by apoptosis at consumer-relevant concentrations of DHA within 72 h. Less is known about systemic exposures to DHA that occur following absorption through skin, and now through inhalation of the aerosolized DHA used in spray tanning. In the present study, HEK293T cells were exposed to consumer-relevant concentrations of DHA to examine the cytotoxicity of systemic exposures. HEK293T cells were sensitive to consumer-relevant doses of DHA with an IC50 value of 2.4 ± 0.3 mM. However, cell cycle arrest did not begin until 48 h after DHA exposure. DHA-exposed cells showed altered metabolic activity with decreased mitochondrial function and decreased lactate and ATP production observed within 24 h of exposure. Autofluorescent imaging and NAD+ sensors also revealed an imbalance in the redox cofactors NAD+/NADH within 24 h of exposure. Cell death occurred by autophagy indicated by increases in LC3B and SIRT1. Despite DHA's ability to be converted to DHAP and integrated into metabolic pathways, the metabolic dysfunction and starvation responses observed in the HEK293T cells indicate that DHA does not readily contribute to the energetic pool in these cells.

Back to Living: Long-term Functional Status of Pediatric Patients Who Completed Intensive Interdisciplinary Pain Treatment.

OBJECTIVES: To provide a descriptive account of long-term functioning (≥5 y posttreatment) among youth who completed intensive interdisciplinary pain treatment (IIPT) for pediatric chronic pain conditions. MATERIALS AND METHODS: A total of 95 patients (mean age at follow-up=20.0 y) treated at least 5 years previously at a single IIPT program completed questionnaires assessing pain, functional disability, health care utilization, academic/career achievement, and quality of life. Data analyses focused on pain, functioning, and progress toward developmental goals at long-term follow-up. RESULTS: The majority of respondents report significant reduction in pain compared with preadmission (P<0.001). Five years posttreatment, average functional disability scores were in the minimal range, with statistically significant decrease in functional disability from time of admission (P<0.001). Nearly 80% of respondents characterized themselves as having no functional difficulties at follow-up. Clinically significant improvement was established for both pain and function. Respondents generally reported developmentally appropriate status, with 89% graduating high school on schedule. DISCUSSION: Results show long-term positive functioning among individuals who underwent intensive rehabilitation treatment for chronic pain as children or adolescents. Despite experiencing one or more pain flares at some point after treatment, most former IIPT patients report minimal to no ongoing functional disability, complete or partial resolution of pain symptoms, and developmentally appropriate progress toward goals (eg, school completion, independent living).

Dihydroxyacetone induces G2/M arrest and apoptotic cell death in A375P melanoma cells.

The active ingredient in sunless tanning products (STPs) is a simple sugar, dihydroxyacetone (DHA). Several studies have demonstrated that DHA is absorbed within the viable layers of skin and not fully contained within the stratum corneum. Additionally, spray tanning and other aerosolized application methods have increased the risk of internal exposure through mucous membranes and inhalation. Beyond its presence in STPs, DHA also occurs as an endogenous by-product of fructose metabolism, and an excess of DHA in cells can induce advanced glycation end (AGE) products and oxidative stress. Therefore, exogenous and endogenous exposures to DHA may be harmful to cells, and it has already been demonstrated that exogenous exposure to DHA is cytotoxic in immortalized keratinocytes. Still, little is known about the exogenous DHA exposure effects on other skin components. In this study, we explore the effects of exogenous DHA exposure in a human melanoma cell line, A375P. Melanoma cells were sensitive to DHA and displayed a transient burst of reactive oxygen species within an hour of exposure. Cell cycle arrest at G2/M was observed within 24 h of exposure, and apoptosis, monitored by the cleavage of PARP-1 and Caspase-3, was detected within 72 h of exposure to DHA. Together, these demonstrate that exogenous exposure to DHA has cytotoxic effects in our selected cell model and indicates the need to further investigate the exogenous exposure effects of DHA in other relevant exposure models.

Feeling the Pressure to Be Perfect: Effect on Pain-Related Distress and Dysfunction in Youth With Chronic Pain.

Despite clinical observation of perfectionistic tendencies among youth with chronic pain and their parents as well as established relationships between perfectionism and functional somatic symptoms in adults and youth, no research in the pediatric pain literature has examined perfectionism. This study explored the role of various types of youth and parent perfectionism on youth and parent pain-related distress and behavior and youth pain-related dysfunction. At admission, 239 parent-child pairs from outpatient and day-treatment rehabilitation settings completed several questionnaires assessing perfectionism, pain-related distress, and pain-related dysfunction. Bivariate correlations indicated that socially prescribed perfectionism in youth and parents was linked to youth pain duration, parent and youth pain-related distress and behavior, and youth somatization. Indirect relations showed that youth socially prescribed perfectionism was the only form of perfectionism directly associated with youth somatization whereas all forms of youth perfectionism were indirectly associated with somatization and functional disability through increases in youth pain-related fear and catastrophizing. Additionally, socially prescribed perfectionism was the only type of parent perfectionism linked to youth pain-related dysfunction (somatization, functional disability) through its association with youth pain-related fear. Findings support clinical observations that parent and youth perfectionism is a psychosocial factor that should be targeted in pediatric chronic pain treatment. PERSPECTIVE: Perfectionism in youth with chronic pain and their parents was indirectly linked to youth pain-related dysfunction through its effect on youth pain-related catastrophizing and fear. Findings support clinical observations that parent and youth perfectionism is a psychosocial factor that should be targeted in pediatric chronic pain treatment.

miR-125b regulates differentiation and metabolic reprogramming of T cell acute lymphoblastic leukemia by directly targeting A20.

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematopoietic malignancy. Although it has been reported that overexpression of miR-125b leads to T-ALL development, the underlying mechanisms of miR-125b action are still unclear. The goal of this study is to delineate the role of miR-125b in T-ALL development. We found that miR-125b is highly expressed in undifferentiated leukemic T cells (CD4-negative) while its expression is low in differentiated T cells (CD4-positive). Overexpression of miR-125b increased the CD4-negative population in T cells, whereas depletion of miR-125b by miR-125b-sponge decreased the CD4-negative cell population. We identified that A20 (TNFAIP3) is a direct target of miR-125b in T cells. Overexpression of miR-125b also increased glucose uptake and oxygen consumption in T cells through targeting A20. Furthermore, restoration of A20 in miR-125b-overexpressing cells decreased the CD4-negative population in T cell leukemia, and decreased glucose uptake and oxygen consumption to the basal level of T cells transfected with vector. In conclusion, our data demonstrate that miR-125b regulates differentiation and reprogramming of T cell glucose metabolism via targeting A20. Since both de-differentiation and dysregulated glucose metabolism contribute to the development of T-cell leukemia, these findings provide novel insights into the understanding and treatment of T-ALL.

Endotoxin recovery using limulus amebocyte lysate (LAL) assay.

A phenomenon initially reported by Chen and Vinther in 2013 [1], and now commonly referred to as low endotoxin recovery (LER), has prompted the Food and Drug Administration (FDA) to request specific data demonstrating the capability of the LAL BET method (i.e., USP <85>) to recover endotoxin from spiked samples over time. The results of these spike/hold recovery studies are expected to be included in the Biologics License Applications (BLA) for review by the Center for Drug Evaluation and Research (CDER) Hughes (2014) and Hughes et al. (2015) [2,3]. Such studies involve spiking a known amount of a surrogate endotoxin, such as purified lipopolysaccharide (LPS), into undiluted biological products and then testing at different time points to determine the recovery over time. We report here the experience and learning gained from conducting spike/hold recovery studies for a monoclonal antibody (Mab) product. Results from initial hold studies spiked with purified LPS showed rapid loss of endotoxin activity in the drug substance (DS) and significant batch-to-batch variation in the drug product (DP). After careful review and examination of the experimental details, it was determined that the study design and execution differed from the routine batch release USP <85> BET method with regard to mixing time and sampling scheme. The hold study design was subsequently revised so that the mixing time and sampling were the same as the verified USP <85> BET method used for routine batch release testing. The spike/hold recovery studies were repeated and the results demonstrated that LPS could be consistently recovered over time. These findings highlight the importance of carefully controlling sample preparation procedures in a spike/hold recovery study in order to demonstrate the suitability of using the LAL BET method for endotoxin detection.

Regulation of mitochondrial functions by protein phosphorylation and dephosphorylation.

The mitochondria are double membrane-bound organelles found in most eukaryotic cells. They generate most of the cell's energy supply of adenosine triphosphate (ATP). Protein phosphorylation and dephosphorylation are critical mechanisms in the regulation of cell signaling networks and are essential for almost all the cellular functions. For many decades, mitochondria were considered autonomous organelles merely functioning to generate energy for cells to survive and proliferate, and were thought to be independent of the cellular signaling networks. Consequently, phosphorylation and dephosphorylation processes of mitochondrial kinases and phosphatases were largely neglected. However, evidence accumulated in recent years on mitochondria-localized kinases/phosphatases has changed this longstanding view. Mitochondria are increasingly recognized as a hub for cell signaling, and many kinases and phosphatases have been reported to localize in mitochondria and play important functions. However, the strength of the evidence on mitochondrial localization and the activities of the reported kinases and phosphatases vary greatly, and the detailed mechanisms on how these kinases/phosphatases translocate to mitochondria, their subsequent function, and the physiological and pathological implications of their localization are still poorly understood. Here, we provide an updated perspective on the recent advancement in this area, with an emphasis on the implications of mitochondrial kinases/phosphatases in cancer and several other diseases.

Evidence against a bacterial endotoxin masking effect in biologic drug products by limulus amebocyte lysate detection.

The inability to detect endotoxin using compendia methods is a potential safety concern for patients due to the lack of endotoxin removal capabilities at the fill-finish stage in typical aseptic biologic drug product manufacturing. We have successfully demonstrated endotoxin challenge study recovery methodology using mammalian cell-produced biologic drug products and drug substances in citrate, histidine, phosphate, and sodium acetate buffer formulations containing polysorbate, challenged with an endotoxin analyte, for up to 6 months of storage. Successful recovery was similarly demonstrated for a preserved, peptide-containing drug product formulation. To isolate a potential masking-or low-endotoxin recovery-source, additional studies were performed to evaluate factors including product manufacturing contact surfaces, drug product matrix with and without polysorbate, individual matrix components, protein concentration, reagent suppliers, an orthogonal test method, and storage conditions. In all cases, acceptable recoveries were observed. Bacterial endotoxin is known to be chemically stable at physiological conditions. Purified endotoxin in aqueous conditions is likely to self-aggregate or bind to surfaces. Neither the nature of, nor the storage conditions of, the studied formulation matrices were shown experimentally to render the challenge endotoxin biologically inactive. The results highlight the importance of appropriate study design in assessing the recovery of endotoxins. LAY ABSTRACT: Bacterial endotoxin is a Gram-negative bacterial cell wall component that is harmful to humans at threshold concentrations, and it is not expected to be in aseptically-produced pharmaceutical medicines. It has been suggested that endotoxin cannot be detected over time in certain biopharmaceutical drug product formulations containing citrate, phosphate, and polysorbate components via an unknown masking mechanism. We have generated and present data here that indicate that endotoxin can be recovered in a variety of matrices, and under various experimental conditions.

Epimacular brachytherapy for neovascular age-related macular degeneration (CABERNET): fluorescein angiography and optical coherence tomography.

PURPOSE: To report the fluorescein angiography (FA) and optical coherence tomography (OCT) results of a clinical trial of epimacular brachytherapy (EMBT) used for the treatment of neovascular age-related macular degeneration (AMD). DESIGN: Pivotal multicenter, active-controlled, randomized clinical trial. PARTICIPANTS: A total of 494 participants with treatment-naïve, neovascular AMD. METHODS: Participants with classic, minimally classic, and occult lesions were randomized to receive (a) EMBT and 2 mandated monthly ranibizumab injections followed by pro re nata (PRN) ranibizumab or (b) 3 mandated monthly ranibizumab injections followed by mandated quarterly plus PRN ranibizumab. Participants underwent FA at screening and at months 1, 6, 12, 18, and 24. Optical coherence tomography scans were undertaken monthly for 24 months. The FA and OCT images were analyzed at respective independent reading centers. MAIN OUTCOME MEASURES: Change at 24 months in mean FA total lesion size and choroidal neovascularization (CNV) size and change in mean OCT centerpoint thickness. RESULTS: The mean (standard deviation) changes in FA total lesion size in the EMBT and control arms were +1.9 (8.7) and -3.0 (7.2) mm(2), respectively, with a mean change in total CNV size of +0.4 (8.4) and -4.7 (6.5) mm(2), respectively. Mean (standard deviation) changes in OCT centerpoint thickness were -144 (246) and -221 (185) µm, respectively. Retrospective subgroup analyses showed no significant difference between treatment arms in mean centerpoint thickness in some subgroups, including eyes with classic lesions. The control arm showed a significantly larger reduction in mean total lesion size and mean CNV size than the EMBT arm in all subgroups analyzed. Nine eyes in the EMBT arm showed features consistent with mild, nonproliferative radiation retinopathy, but with a mean gain of 5.0 Early Treatment Diabetic Retinopathy Study letters. CONCLUSIONS: Both FA and OCT suggest that EMBT with PRN ranibizumab results in an inferior structural outcome than quarterly plus PRN ranibizumab. Some subgroup analyses suggest that classic lesions may be more responsive than occult lesions, although generally both subgroups are inferior to ranibizumab. A non-vision-threatening radiation retinopathy occurs in 2.9% of eyes over 24 months, but longer follow-up is needed. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Early developmental lead exposure increases sensitivity to cocaine in a self-administration paradigm.

The purpose of this investigation was to determine if lead exposure during pregnancy and nursing alters cocaine sensitivity later in the adult cycle, although lead exposure had been discontinued following early development. Female rats were exposed via gavage to 0 or 16 mg/kg lead daily for 30 days prior to breeding with nonexposed males. The respective daily exposure regimens continued throughout gestation and lactation (perinatal lead exposure). Lead exposure was discontinued on the day of weaning (postnatal day [PND] 21). Beginning on PND 70, male offspring were trained to self-administer cocaine HCl intravenously. Examination of a range of cocaine doses (0.030, 0.060, 0.125, 0.250, and 0.500 mg/kg/infusion) revealed that, as adults, animals exposed to lead during early development self-administered cocaine at significantly greater rates at a low dose of the drug. In addition, self-administration rates were lower among lead-exposed animals at higher doses of cocaine. These findings were observed in metal-exposed animals where blood and brain tissue levels had returned to the levels of controls. Collectively, these data suggest that early developmental lead exposure may increase sensitivity to cocaine later in the life cycle.

Developmental exposure to cadmium alters responsiveness to cocaine in the rat.

The purpose of the present report was to investigate the potential interactive relation between perinatal (gestation/lactation) cadmium exposure and changes in responsiveness to cocaine. In Experiment 1, adult female rats were exposed to a diet containing 50 ppm cadmium (as cadmium chloride) or a diet containing no added cadmium for 30 days prior to breeding with nonexposed males. The metal-exposure regimen continued throughout gestation, and for 15 days of lactation, at which time all animals were placed on standard rat chow diets containing no added cadmium for the remainder of the investigation. Atomic absorption assays confirmed that cadmium concentrations were significantly elevated in metal-exposed dams, littermates, and test animals. Offspring were weaned on postnatal day (PND) 21 and commenced cocaine sensitization testing on PND 70. Testing operations for controls and animals perinatally exposed to cadmium consisted of 21 daily i.p. injections of vehicle (saline) or 10 mg/kg cocaine HCl, and subsequent recording of locomotor activity. Subsequently, across successive days, all animals received 0, 10, and 20 mg/kg cocaine challenges. The results showed that cocaine sensitization was attenuated in animals perinatally exposed to cadmium. A similar pattern of antagonism was observed in Experiment 2 where a higher dose of cocaine was required to produce conditioned place preference (CPP) in cadmium-exposed animals. The implications of these findings with respect to the interactive role of cadmium in the dynamics of cocaine use/abuse remain unclear.

The effects of developmental cadmium exposure on morphine sensitization and challenge with selective D(1) and D(2) antagonists.

The purpose of this investigation was to determine the effects of developmental (perinatal) cadmium exposure on the development and expression of behavioral sensitization to morphine. Adult female rats were maintained ad libitum on diets containing 0, 25, or 50 ppm added cadmium (administered as cadmium chloride) for 30 days prior to breeding with nonexposed males. This exposure regimen continued throughout the gestational period and for 15 days postnatally during lactation, at which time regular rat chow was provided. On postnatal day (PND) 21, male pups from the respective litters were weaned and placed on an unadulterated food supply (no added cadmium) and tap water for the remainder of the study. Beginning on PND 70, animals from each exposure condition (0, 25, 50 ppm exposure conditions) received, for 21 consecutive days, either vehicle (distilled water) or 10 mg/kg morphine sulfate injections (ip) prior to being monitored for locomotor activity during 80-min test sessions. Following this 21-day period of morphine sensitization training, dose-effect profiles were determined for each exposure condition with successive daily challenges of 0, 10, and 20 mg/kg morphine. Subsequently, different doses of the D(1) antagonist SCH 23390 (0.01, 0.056, and 0.10 mg/kg) and the D(2) antagonist eticlopride (0.01 and 0.056 mg/kg) were presented prior to administration of the training dose of morphine (10 mg/kg). The results of the investigation revealed that developmental cadmium exposure attenuated the development/expression of morphine sensitization. Furthermore, it was found that the suppressive effects of the D(2) antagonist eticlopride were decreased by early cadmium exposure.