Placental Remote Control of Fetal Metabolism: Trophoblast mTOR Signaling Regulates Liver IGFBP-1 Phosphorylation and IGF-1 Bioavailability.

The mechanisms mediating the restricted growth in intrauterine growth restriction (IUGR) remain to be fully established. Mechanistic target of rapamycin (mTOR) signaling functions as a placental nutrient sensor, indirectly influencing fetal growth by regulating placental function. Increased secretion and the phosphorylation of fetal liver IGFBP-1 are known to markedly decrease the bioavailability of IGF-1, a major fetal growth factor. We hypothesized that an inhibition of trophoblast mTOR increases liver IGFBP-1 secretion and phosphorylation. We collected conditioned media (CM) from cultured primary human trophoblast (PHT) cells with a silenced RAPTOR (specific inhibition of mTOR Complex 1), RICTOR (inhibition of mTOR Complex 2), or DEPTOR (activates both mTOR Complexes). Subsequently, HepG2 cells, a well-established model for human fetal hepatocytes, were cultured in CM from PHT cells, and IGFBP-1 secretion and phosphorylation were determined. CM from PHT cells with either mTORC1 or mTORC2 inhibition caused the marked hyperphosphorylation of IGFBP-1 in HepG2 cells as determined by 2D-immunoblotting while Parallel Reaction Monitoring-Mass Spectrometry (PRM-MS) identified increased dually phosphorylated Ser169 + Ser174. Furthermore, using the same samples, PRM-MS identified multiple CK2 peptides coimmunoprecipitated with IGFBP-1 and greater CK2 autophosphorylation, indicating the activation of CK2, a key enzyme mediating IGFBP-1 phosphorylation. Increased IGFBP-1 phosphorylation inhibited IGF-1 function, as determined by the reduced IGF-1R autophosphorylation. Conversely, CM from PHT cells with mTOR activation decreased IGFBP-1 phosphorylation. CM from non-trophoblast cells with mTORC1 or mTORC2 inhibition had no effect on HepG2 IGFBP-1 phosphorylation. Placental mTOR signaling may regulate fetal growth by the remote control of fetal liver IGFBP-1 phosphorylation.

Mechanisms linking hypoxia to phosphorylation of insulin-like growth factor binding protein-1 in baboon fetuses with intrauterine growth restriction and in cell culture.

Hypoxia increases fetal hepatic insulin-like growth factor binding protein-1 (IGFBP-1) phosphorylation mediated by mechanistic target of rapamycin (mTOR) inhibition. Whether maternal nutrient restriction (MNR) causes fetal hypoxia remains unclear. We used fetal liver from a baboon (Papio sp.) model of intrauterine growth restriction due to MNR (70% global diet of Control) and liver hepatocellular carcinoma (HepG2) cells as a model for human fetal hepatocytes and tested the hypothesis that mTOR-mediated IGFBP-1 hyperphosphorylation in response to hypoxia requires hypoxia-inducible factor-1α (HIF-1α) and regulated in development and DNA-damage responses-1 (REDD-1) signaling. Western blotting (n = 6) and immunohistochemistry (n = 3) using fetal liver indicated greater expression of HIF-1α, REDD-1 as well as erythropoietin and its receptor, and vascular endothelial growth factor at GD120 (GD185 term) in MNR versus Control. Moreover, treatment of HepG2 cells with hypoxia (1% pO2 ) (n = 3) induced REDD-1, inhibited mTOR complex-1 (mTORC1) activity and increased IGFBP-1 secretion/phosphorylation (Ser101/Ser119/Ser169). HIF-1α inhibition by echinomycin or small interfering RNA silencing prevented the hypoxia-mediated inhibition of mTORC1 and induction of IGFBP-1 secretion/phosphorylation. dimethyloxaloylglycine (DMOG) induced HIF-1α and also REDD-1 expression, inhibited mTORC1 and increased IGFBP-1 secretion/phosphorylation. Induction of HIF-1α (DMOG) and REDD-1 by Compound 3 inhibited mTORC1, increased IGFBP-1 secretion/ phosphorylation and protein kinase PKCα expression. Together, our data demonstrate that HIF-1α induction, increased REDD-1 expression and mTORC1 inhibition represent the mechanistic link between hypoxia and increased IGFBP-1 secretion/phosphorylation. We propose that maternal undernutrition limits fetal oxygen delivery, as demonstrated by increased fetal liver expression of hypoxia-responsive proteins in baboon MNR. These findings have important implications for our understanding of the pathophysiology of restricted fetal growth.

Exploring Heterogeneous Dynamical Environment around an Ensemble of Aß42 Peptide Monomer Conformations.

Exploring the conformational properties of amyloid ß (Aß) peptides and the role of solvent (water) in guiding the dynamical environment at their interfaces is crucial for microscopic understanding of Aß misfolding, which is involved in causing the most common neurodegenerative disorder, i.e., Alzheimer's disease. While numerous studies in the past have emphasized examining the conformational states of Aß peptides, the role of water has not received much attention. Here, we have performed all-atom molecular dynamics simulations of several full-length Aß42 peptide monomers with different initial configurations. Our efforts are directed toward probing the origin of the heterogeneous dynamics of water around various segments of the Aß peptide, identified as the two terminal segments (N-term and C-term) and the two hydrophobic segments (hp1 and hp2), along with the central turn region interconnecting hp1 and hp2. Our results revealed that water hydrating hp1, hp2, and turn (nonterminal segments) and C-term segments exhibit nonuniformly restricted translational as well as rotational motions. The degree of such restriction has been found to be correlated with the hydrogen bond relaxation time scales at the interface. Importantly, it is revealed that the water molecules around hp1 and, to some extent, around hp2, form relatively rigid hydration layers, compared to that around the other segments. Such rigid hydration layers arise due to relatively more solid-like caging motions resulting in relatively lesser hydration entropy. As hp1 and hp2 have been demonstrated to play a central role in Aß aggregation, we believe that distinct water dynamics in the vicinity of these two segments, as outlined in this study, can provide vital information in understanding the early stages of the onset of the aggregation process of such peptides at higher concentration that can further aid toward advances in AD therapeutics.

Molecular dynamics analysis of the binding of human interleukin-6 with interleukin-6 α-receptor.

Human interleukin-6 (hIL-6) is a multifunctional cytokine that regulates immune and inflammatory responses in addition to metabolic and regenerative processes and cancer. hIL-6 binding to the IL-6 receptor (IL-6Rα) induces homodimerization and recruitment of the glycoprotein (gp130) to form a hexameric signaling complex. Anti-IL-6 and IL-6R antibodies are clinically approved inhibitors of IL-6 signaling pathway for treating rheumatoid arthritis and Castleman's disease, respectively. There is a potential to develop novel small molecule IL-6 antagonists derived from understanding the structural basis for IL-6/IL-6Rα interactions. Here, we combine homology modeling with extensive molecular dynamics (MD) simulations to examine the association of hIL-6 with IL-6Rα. A comparison with MD of apo hIL-6 reveals that the binding of hIL-6 to IL-6Rα induces structural and dynamic rearrangements in the AB loop region of hIL-6, disrupting intraprotein contacts and increasing the flexibility of residues 48 to 58 of the AB loop. In contrast, due to the involvement of residues 59 to 78 in forming contacts with the receptor, these residues of the AB loop are observed to rigidify in the presence of the receptor. The binary complex is primarily stabilized by two pairs of salt bridges, Arg181 (hIL-6)- Glu182 (IL-6Rα) and Arg184 (hIL-6)- Glu183 (IL-6Rα) as well as hydrophobic and aromatic stacking interactions mediated essentially by Phe residues in both proteins. An interplay of electrostatic, hydrophobic, hydrogen bonding, and aromatic stacking interactions facilitates the formation of the hIL-6/IL-6Rα complex.

Hyperphosphorylation of fetal liver IGFBP-1 precedes slowing of fetal growth in nutrient-restricted baboons and may be a mechanism underlying IUGR.

In cultured fetal liver cells, insulin-like growth factor (IGF) binding protein (IGFBP)-1 hyperphosphorylation in response to hypoxia and amino acid deprivation is mediated by inhibition of mechanistic target of rapamycin (mTOR) and activation of amino acid response (AAR) signaling and casein kinase (CK)2. We hypothesized that fetal liver mTOR inhibition, activation of AAR and CK2, and IGFBP-1 hyperphosphorylation occur before development of intrauterine growth restriction (IUGR). Pregnant baboons were fed a control (C) or a maternal nutrient restriction (MNR; 70% calories of control) diet starting at gestational day (GD) 30 (term GD 185). Umbilical blood and fetal liver tissue were obtained at GD 120 (C, n = 7; MNR, n = 10) and 165 (C, n = 7; MNR, n = 8). Fetal weights were unchanged at GD 120 but decreased at GD 165 in the MNR group (-13%, P = 0.03). IGFBP-1 phosphorylation, as determined by parallel reaction monitoring mass spectrometry (PRM-MS), immunohistochemistry, and/or Western blot, was enhanced in MNR fetal liver and umbilical plasma at GD 120 and 165. IGF-I receptor autophosphorylationTyr1135 (-64%, P = 0.05) was reduced in MNR fetal liver at GD 120. Furthermore, fetal liver CK2 (α/α'/ß) expression, CK2ß colocalization, proximity with IGFBP-1, and CK2 autophosphorylationTyr182 were greater at GD 120 and 165 in MNR vs. C. Additionally, mTOR complex (mTORC)1 (p-P70S6KThr389, -52%, P = 0.05) and mTORC2 (p-AktSer473, -56%, P < 0.001) activity were decreased and AAR was activated (p-GCN2Thr898, +117%, P = 0.02; p-eIF2αSer51, +294%, P = 0.002; p-ERKThr202, +111%, P = 0.03) in MNR liver at GD 120. Our data suggest that fetal liver IGFBP-1 hyperphosphorylation, mediated by mTOR inhibition and both AAR and CK2 activation, is a key link between restricted nutrient and oxygen availability and the development of IUGR.

Horizontal transfer of a pathway for coumarate catabolism unexpectedly inhibits purine nucleotide biosynthesis.

A microbe's ecological niche and biotechnological utility are determined by its specific set of co-evolved metabolic pathways. The acquisition of new pathways, through horizontal gene transfer or genetic engineering, can have unpredictable consequences. Here we show that two different pathways for coumarate catabolism failed to function when initially transferred into Escherichia coli. Using laboratory evolution, we elucidated the factors limiting activity of the newly acquired pathways and the modifications required to overcome these limitations. Both pathways required host mutations to enable effective growth with coumarate, but the necessary mutations differed. In one case, a pathway intermediate inhibited purine nucleotide biosynthesis, and this inhibition was relieved by single amino acid replacements in IMP dehydrogenase. A strain that natively contains this coumarate catabolism pathway, Acinetobacter baumannii, is resistant to inhibition by the relevant intermediate, suggesting that natural pathway transfers have faced and overcome similar challenges. Molecular dynamics simulation of the wild type and a representative single-residue mutant provide insight into the structural and dynamic changes that relieve inhibition. These results demonstrate how deleterious interactions can limit pathway transfer, that these interactions can be traced to specific molecular interactions between host and pathway, and how evolution or engineering can alleviate these limitations.

Down-regulation of placental Cdc42 and Rac1 links mTORC2 inhibition to decreased trophoblast amino acid transport in human intrauterine growth restriction.

Intrauterine growth restriction (IUGR) increases the risk for perinatal complications and metabolic and cardiovascular disease later in life. The syncytiotrophoblast (ST) is the transporting epithelium of the human placenta, and decreased expression of amino acid transporter isoforms in the ST plasma membranes is believed to contribute to IUGR. Placental mechanistic target of rapamycin Complex 2 (mTORC2) signaling is inhibited in IUGR and regulates the trafficking of key amino acid transporter (AAT) isoforms to the ST plasma membrane; however, the molecular mechanisms are unknown. Cdc42 and Rac1 are Rho-GTPases that regulate actin-binding proteins, thereby modulating the structure and dynamics of the actin cytoskeleton. We hypothesized that inhibition of mTORC2 decreases AAT expression in the plasma membrane and amino acid uptake in primary human trophoblast (PHT) cells mediated by down-regulation of Cdc42 and Rac1. mTORC2, but not mTORC1, inhibition decreased the Cdc42 and Rac1 expression. Silencing of Cdc42 and Rac1 inhibited the activity of the System L and A transporters and markedly decreased the trafficking of LAT1 (System L isoform) and SNAT2 (System A isoform) to the plasma membrane. mTORC2 inhibition by silencing of rictor failed to decrease AAT following activation of Cdc42/Rac1. Placental Cdc42 and Rac1 protein expression was down-regulated in human IUGR and was positively correlated with placental mTORC2 signaling. In conclusion, mTORC2 regulates AAT trafficking in PHT cells by modulating Cdc42 and Rac1. Placental mTORC2 inhibition in human IUGR may contribute to decreased placental amino acid transfer and reduced fetal growth mediated by down-regulation of Cdc42 and Rac1.

Novel roles of mechanistic target of rapamycin signaling in regulating fetal growth†.

Mechanistic target of rapamycin (mTOR) signaling functions as a central regulator of cellular metabolism, growth, and survival in response to hormones, growth factors, nutrients, energy, and stress signals. Mechanistic TOR is therefore critical for the growth of most fetal organs, and global mTOR deletion is embryonic lethal. This review discusses emerging evidence suggesting that mTOR signaling also has a role as a critical hub in the overall homeostatic control of fetal growth, adjusting the fetal growth trajectory according to the ability of the maternal supply line to support fetal growth. In the fetus, liver mTOR governs the secretion and phosphorylation of insulin-like growth factor binding protein 1 (IGFBP-1) thereby controlling the bioavailability of insulin-like growth factors (IGF-I and IGF-II), which function as important growth hormones during fetal life. In the placenta, mTOR responds to a large number of growth-related signals, including amino acids, glucose, oxygen, folate, and growth factors, to regulate trophoblast mitochondrial respiration, nutrient transport, and protein synthesis, thereby influencing fetal growth. In the maternal compartment, mTOR is an integral part of a decidual nutrient sensor which links oxygen and nutrient availability to the phosphorylation of IGFBP-1 with preferential effects on the bioavailability of IGF-I in the maternal-fetal interface and in the maternal circulation. These new roles of mTOR signaling in the regulation fetal growth will help us better understand the molecular underpinnings of abnormal fetal growth, such as intrauterine growth restriction and fetal overgrowth, and may represent novel avenues for diagnostics and intervention in important pregnancy complications.

Co-Localization of Insulin-Like Growth Factor Binding Protein-1, Casein Kinase-2ß, and Mechanistic Target of Rapamycin in Human Hepatocellular Carcinoma Cells as Demonstrated by Dual Immunofluorescence and in Situ Proximity Ligation Assay.

Insulin-like growth factor binding protein (IGFBP)-1 influences fetal growth by modifying insulin-like growth factor-I (IGF-I) bioavailability. IGFBP-1 phosphorylation, which markedly increases its affinity for IGF-I, is regulated by mechanistic target of rapamycin (mTOR) and casein kinase (CSNK)-2. However, the underlying molecular mechanisms remain unknown. We examined the cellular localization and potential interactions of IGFBP-1, CSNK-2ß, and mTOR as a prerequisite for protein-protein interaction. Analysis of dual immunofluorescence images indicated a potential perinuclear co-localization between IGFBP-1 and CSNK-2ß and a nuclear co-localization between CSNK-2ß and mTOR. Proximity ligation assay (PLA) indicated proximity between IGFBP-1 and CSNK-2ß as well as mTOR and CSNK-2ß but not between mTOR and IGFBP-1. Three-dimensional rendering of the PLA images validated that IGFBP-1 and CSNK-2ß interactions were in the perinuclear region and mTOR and CSNK-2ß interactions were also predominantly perinuclear rather than nuclear as indicated by mTOR and CSNK-2ß co-localization. Compared with control, hypoxia and rapamycin treatment showed markedly amplified PLA signals for IGFBP-1 and CSNK-2ß (approximately 18-fold, P = 0.0002). Stable isotope labeling with multiple reaction monitoring-mass spectrometry demonstrated that hypoxia and rapamycin treatment increased IGFBP-1 phosphorylation at Ser98/Ser101/Ser119/Ser174 but most considerably (106-fold) at Ser169. We report interactions between CSNK-2ß and IGFBP-1 as well as mTOR and CSNK-2ß, providing strong evidence of a mechanistic link between mTOR and IGF-I signaling, two critical regulators of cell growth via CSNK-2.

Alterations in placental long chain polyunsaturated fatty acid metabolism in human intrauterine growth restriction.

Fatty acids (FA) are critical for fetal brain development and are transferred across the placenta by membrane-bound FA transport proteins (FATP), translocases (FAT/CD36), and cytosolic binding proteins (FABP). The cytosolic protein perilipin-2 aids in neutral lipid storage within lipid droplets. Decreased placental nutrient transport is believed to contribute to intrauterine growth restriction (IUGR); however, IUGR placental lipid transport and metabolism are poorly understood. We hypothesized that protein expression of FATPs, FABPs, and perilipin-2 in human placenta is decreased and placental lipid content and incorporation into lipid classes are reduced in IUGR. Placental tissue of idiopathic IUGR (n=25) and gestational age-matched, appropriately grown for gestational age (AGA) fetuses (n=19) was collected. We determined protein expression of FABP4 and perilipin-2 in placental homogenate and FATPs (2, 4, 6, CD36) in syncytiotrophoblast microvillous plasma membrane (MVM) by Western blot. Lipid droplet area (Oil Red O stain) and cellular FA content (GC/MS) were measured in chorionic villous tissue. MVM expression of FATP6 and CD36 was significantly increased in IUGR. The concentrations of seven n-6 and n-3 species long chain polyunsaturated FAs (LCPUFA) were significantly increased in the triglyceride fraction in IUGR vs AGA placenta. In summary, MVM FATP6 and CD36 protein expression is increased and LCPUFA are preferentially routed toward cellular storage in TG in the IUGR placenta, possibly to protect against oxidative stress associated with cellular FA accumulation. We speculate that these changes may be caused by impaired efflux of FA across the fetal-facing syncytiotrophoblast basal plasma membrane in IUGR placenta.

Understanding the Nature of Amino Acid Interactions with Pd(111) or Pd-Au Bimetallic Catalysts in the Aqueous Phase.

The interaction of methionine (Met) with different bimetallic-segregated surfaces comprising a uniform distribution of strips and islands of Au on the Pd(111) surface was examined using molecular dynamics (MD) simulations. Out of all the segregated and uniformly doped surfaces studied, the design of Pd-Au islands showed some reduction in the interaction energy (Eint = -43.7 kJ/mol) as compared to that of the pure Pd(111) surface (Eint = -50 kJ/mol) for a single Met molecule. However, at a higher coverage of 9 Met molecules/simulation cell, none of the Pd-Au alloy surfaces showed any improvement as compared to the Pd(111) surface. In order to develop a comprehensive understanding of the nature of the nonbonded interaction of aqueous biogenic impurities with the Pd catalyst surface, the MD study was extended to include a variety of aliphatic, S-containing, aromatic, and polar amino acids. The potential of mean force (PMF) profiles were observed to be distinct for each class of amino acids with substantial differences among amino acids with acidic and basic side chains. The side chains of all the polar and aromatic amino acids showed direct contact with the surface while aliphatic amino acids had their hydrophobic side chain aligned away from the surface. Interestingly, lysine (Lys) and tyrosine (Tyr) were the only two amino acids which interacted preferentially via the distant backbone nitrogen and backbone oxygen, respectively, despite their side chains being in direct contact with the metal surface. The strength of interaction was correlated with the size of the amino acid; the interaction energies were observed to be the maximum for large molecules such as arginine (Arg, Eint = -87.7 kJ/mol) and tryptophan (Trp, Eint = -73.4 kJ/mol), while it was a minimum for aliphatic amino acids such as alanine (Ala, Eint = -10.9 kJ/mol). The study is focused on examining the sensitivity of the choice of the preferential interaction site, conformational preferences, and interaction energies to the side-chain specificity.

The sensitivity of folding free energy landscapes of trpzips to mutations in the hydrophobic core.

The sensitivity of the stability of folded states and free energy landscapes to the differences in the hydrophobic content of the core residues has been studied for the set of 16-residue trpzips, namely, Trpzip4, Trpzip5 and Trpzip6. The combination of principal component analysis and different secondary structure order metrics as reaction coordinates has been used to characterize and identify all the underlying attractive basins corresponding to the folded and the unfolded states for each trpzip at 300 K. Our results reveal that even a single mutation in the hydrophobic core perturbs the stability of the folded peptide and the conformational preferences for the partially folded and unfolded states significantly, leading to concomitant alterations in the free energy landscape of trpzips. Trpzip4 is observed to have the most rugged and variegated free energy landscape with occurrence of four metastable unfolded states in addition to the folded native state. In contrast, Trpzip5 and Trpzip6 are characterized by two such metastable states. The order metrics pertaining to the rigidity of the turn residues and the distances between the side chains of the hydrophobic core residues have been found to be most revealing to understand the degree of discrimination among the folded states of different peptides in addition to the unfolded states. Our results suggest that both turn propensity and hydrophobic interactions influence the thermodynamics of the folding pathways of trpzips. The implications of the sequence dependent response of amino acids, effect of aromatic stacking interactions and packing of protein's interior for shaping the free energy landscape of the peptides have been highlighted.

Comparison of hydration behavior and conformational preferences of the Trp-cage mini-protein in different rigid-body water models.

The secondary structure conformational properties and hydration shell metrics of the Trp-cage mini-protein are examined in the folded and unfolded ensembles in mTIP3P, TIP4P, and TIP4P-Ew water models with the CHARMM22 force-field using molecular dynamics simulations at 250 K. Upon changing the water model, the conformational order metrics of the peptide show significant differences in the unfolded rather than in the folded ensemble. The unfolding temperatures for Trp-cage are observed to be around 460, 470, and 430 K in mTIP3P, TIP4P, and TIP4P-Ew, respectively. Upon comparing the results with a previous study on a 16-residue ß-hairpin fragment of the 2GB1 protein, the same set of conformational order metrics are found to be insufficient in describing the free energy landscape of peptides having a distinct native secondary structure. However, the hydration shell properties of the peptide have been found to be independent of the sequence of the peptide and it changes in conformation upon unfolding. Our calculations reveal that for a particular water model, the secondary structure preferences in the unfolded ensembles of the two peptides are qualitatively different. The unfolded structures of Trp-cage prefer extended and compact structures in TIP4P-Ew and mTIP3P water, respectively, whereas the ß-hairpin peptide prefers extended unfolded structures in mTIP3P. The conformational preferences of the unfolded peptide in a given water model have been found to depend on the peptide sequence, where the binding energies of the water molecules around the polar residues in the unfolded conformations show sensitivity to the multipole moments of the water models. The significance of an accurate description of peptide-solvent interactions in the parametrization of biomolecular force-fields, to obtain an accurate description of conformational preferences, in particular in the unfolded ensembles of proteins, is highlighted.

Increased ubiquitination and reduced plasma membrane trafficking of placental amino acid transporter SNAT-2 in human IUGR.

Placental amino acid transport is decreased in intrauterine growth restriction (IUGR); however, the underlying mechanisms remain largely unknown. We have shown that mechanistic target of rapamycin (mTOR) signalling regulates system A amino acid transport by modulating the ubiquitination and plasma membrane trafficking of sodium-coupled neutral amino acid transporter 2 (SNAT-2) in cultured primary human trophoblast cells. We hypothesize that IUGR is associated with (1) inhibition of placental mTORC1 and mTORC2 signalling pathways, (2) increased amino acid transporter ubiquitination in placental homogenates and (3) decreased protein expression of SNAT-2 in the syncytiotrophoblast microvillous plasma membrane (MVM). To test this hypothesis, we collected placental tissue and isolated MVM from women with pregnancies complicated by IUGR (n=25) and gestational age-matched women with appropriately grown control infants (n=19, birth weights between the twenty-fifth to seventy-fifth percentiles). The activity of mTORC1 and mTORC2 was decreased whereas the protein expression of the ubiquitin ligase NEDD4-2 (neural precursor cell expressed developmentally down-regulated protein 4-2; +72%, P<0.0001) and the ubiquitination of SNAT-2 (+180%, P<0.05) were increased in homogenates of IUGR placentas. Furthermore, IUGR was associated with decreased system A amino acid transport activity (-72%, P<0.0001) and SNAT-1 (-42%, P<0.05) and SNAT-2 (-31%, P<0.05) protein expression in MVM. In summary, these findings are consistent with the possibility that decreased placental mTOR activity causes down-regulation of placental system A activity by shifting SNAT-2 trafficking towards proteasomal degradation, thereby contributing to decreased fetal amino acid availability and restricted fetal growth in IUGR.

Trichotillomania: Demographic and Clinical Features From a Nationally Representative US Sample.

Trichotillomania (TTM) is a psychodermatologic disorder that is typically first seen in the dermatology clinic. There are no reported studies of TTM from nationally representative samples. The authors examined epidemiologic and clinical characteristics of an estimated 695,588±136,456 (unweighted count = 89) patient visits with physician-diagnosed TTM (using International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] code 312.39) from a nationally representative US sample. An estimated 20.6%±7.4% visits for TTM were by patients 12 years and younger and demonstrated no sex difference (P=.52). Overall, TTM patients were younger (mean age: 24.01±3.09 years) (P<.001) and more likely to be female (80.3%±6.2%) (P=.003). These demographic findings are consistent with standard diagnostic criteria for TTM (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition). There were no racial (white vs nonwhite) differences in TTM frequency. Psychiatric disorders were seen in 75.5%±9.1% of TTM patient visits, with depressive disorder being the most common comorbidity (37.8%±9.5%) and selective serotonin reuptake inhibitor antidepressants the most commonly (50.6%±9.7%) used medication. These findings highlight the importance of psychiatric comorbidity in TTM.

Current concepts in psychodermatology.

Several diagnoses in the new DSM-5 chapter on 'Obsessive-Compulsive and Related Disorders' directly relate to psychodermatology. The new excoriation (skin-picking) disorder (SPD) and trichotillomania (TTM) both manifest as recurrent body-focused repetitive behaviors that have compulsive and dissociative features, the latter being more prevalent in TTM than SPD. The DSM-5 refers to SPD and TTM occurring without full awareness or preceding tension, however does not specifically mention the possible role of dissociation. This has important treatment implications, as patients with high dissociative symptoms are not likely to respond to the standard treatments for obsessive-compulsive disorder. Body dysmorphic disorder (BDD), which is frequently associated with cutaneous body image (CBI) dissatisfaction, is present in 9%-15% of dermatology patients. Treatment guidelines in dermatology are increasingly considering the psychosocial morbidity related to CBI in their treatment outcome measures. The presence of BDD, if unrecognized, may therefore directly affect the dermatologic treatment regimens offered to the patient.

Effects of maternal nutrient restriction, intrauterine growth restriction, and glucocorticoid exposure on phosphoenolpyruvate carboxykinase-1 expression in fetal baboon hepatocytes in vitro.

BACKGROUND: The objective of this study was to develop a cell culture system for fetal baboon hepatocytes and to test the hypotheses that (i) expression of the gluconeogenic enzyme phosphoenolpyruvate carboxykinase-1 (PEPCK-1) is upregulated in hepatocytes isolated from fetuses of nutrient-restricted mothers (MNR) compared with ad libitum-fed controls (CTR), and (ii) glucocorticoids stimulate PEPCK-1 expression. METHODS: Hepatocytes from 0.9G CTR and MNR fetuses were isolated and cultured. PEPCK-1 protein and mRNA levels in hepatocytes were determined by Western blot and quantitative PCR, respectively. RESULTS: Fetuses of MNR mothers were intrauterine growth restricted (IUGR). Feasibility of culturing 0.9G fetal baboon hepatocytes was demonstrated. PEPCK-1 protein levels were increased in hepatocytes isolated from IUGR fetuses, and PEPCK-1 mRNA expression was stimulated by glucocorticoids in fetal hepatocytes. CONCLUSIONS: Cultured fetal baboon hepatocytes that retain their in vivo phenotype provide powerful in vitro tools to investigate mechanisms that regulate normal and programmed hepatic function.

Review of somatic symptoms in post-traumatic stress disorder.

Post-traumatic stress disorder (PTSD) is associated with both (1) 'ill-defined' or 'medically unexplained' somatic syndromes, e.g. unexplained dizziness, tinnitus and blurry vision, and syndromes that can be classified as somatoform disorders (DSM-IV-TR); and (2) a range of medical conditions, with a preponderance of cardiovascular, respiratory, musculoskeletal, neurological, and gastrointestinal disorders, diabetes, chronic pain, sleep disorders and other immune-mediated disorders in various studies. Frequently reported medical co-morbidities with PTSD across various studies include cardiovascular disease, especially hypertension, and immune-mediated disorders. PTSD is associated with limbic instability and alterations in both the hypothalamic- pituitary-adrenal and sympatho-adrenal medullary axes, which affect neuroendocrine and immune functions, have central nervous system effects resulting in pseudo-neurological symptoms and disorders of sleep-wake regulation, and result in autonomic nervous system dysregulation. Hypervigilance, a central feature of PTSD, can lead to 'local sleep' or regional arousal states, when the patient is partially asleep and partially awake, and manifests as complex motor and/or verbal behaviours in a partially conscious state. The few studies of the effects of standard PTSD treatments (medications, CBT) on PTSD-associated somatic syndromes report a reduction in the severity of ill-defined and autonomically mediated somatic symptoms, self-reported physical health problems, and some chronic pain syndromes.

Cutaneous sensory disorder.

Cutaneous sensory disorder (CSD) represents a heterogeneous clinical situation where the patient presents with either disagreeable skin sensations (ie, itching, burning, stinging) or pain (ie, allodynia) and/or negative sensory symptoms (ie, numbness, hypoaesthesia). These patients have no apparent diagnosable dermatologic or medical condition that explains the cutaneous symptom, and typically have negative findings upon medical workup. Skin regions that normally have a greater density of epidermal innervation tend to be more susceptible to the development of CSD. CSDs can affect any body region but generally tend to be confined to the face, scalp and perineum, and have been referred to in the literature with region-specific terms such as burning mouth syndrome, glossodynia and vulvodynia. Symptoms such as pruritus with unexplained hyperhidrosis may occur during sleep, as a result of heightened sympathetic tone. Sleep deprivation and insomnia can play a moderating role in CSD. Somatization and dissociation can play a central role in the pathogenesis of CSDs. A review of the literature suggests that CSDs represent a complex, and often poorly understood interplay between neurobiological factors associated with neuropathic pain, neuropathic itch and neurologic/neuropsychiatric states (eg, radiculopathies, stroke, depression and posttraumatic stress disorder). These neurologic/neuropsychiatric states can modulate pain and itch perception by potentially affecting the pain and itch pathways at a structural and/or functional level.

Polypharmacy in dermatology: analysis of a nationally representative sample of 46,273 dermatology patient visits in the United States from 1995 to 2009.

There are no large-scale studies ofpolypharmacy (PP) in dermatology. The authors examined trends in PP (simultaneous use of > or = 4 medications in our study) and associated clinical factors among a nationally representative sample of 46,273 (weighted count +/- standard error [SE]: 617,970,596 +/- 25,187,959) dermatology-related (International Classification of Diseases, Ninth Revision, Clinical Modification codes 680-709) patient visits from 1995 to 2009. Data from the National Ambulatory Medical Care Survey and the National Hospital Ambulatory Care Survey were examined. The overall frequency (+/- SE) of PP was 8.9% +/- 0.4%. There was almost a doubling in the frequency of PP in dermatology from 1995 to 2009 (odds ratio [OR], 2.02; 95% confidence interval [CI], 1.67-2.44, after controlling for comorbidities and sex). This increase was noted among patients with > 1 diagnoses, and all age groups including the younger than 25 age category (PP frequency +/- SE, 7.4% +/- 0.4%; OR, 1.45; 95% CI, 1.12-1.88), and not just among patients in the geriatric age range with multiple complex dermatologic problems. Some of the most frequent conditions in the PP group included acne, psoriasis, atopic dermatitis, and infections of the skin and subcutaneous tissue, conditions that are known to be affected by psychodermatologic factors. PP among these patients may in part be an indication of their complex presentation caused by psychosocial vs dermatopathologic factors.