Pichia kudriavzevii as feed additive in Nile tilapia (Oreochromis niloticus) diet.

Yeasts are unicellular eukaryotic microorganisms extensively employed in various applications, notably as an alternative source of protein in feeds, owing to their nutritional benefits. Despite their potential, marine and mangrove yeast species used in the aquaculture industry have received little attention in the Philippines. Pichia kudriavzevii (A2B R1 ISO 3), sourced from bark samples, was selected and mass-produced due to its high protein content and amino acid profile. The dried biomass of P. kudriavzevii was incorporated into the diets of Nile tilapia (Oreochromis niloticus) juveniles at varying inclusion levels (0, 1, 2, and 4 g/kg diet) and its effect on their growth performance, body composition, and liver and intestinal morphology was assessed after 40 days of feeding. The groups that received P. kudriavzevii at a concentration of 2 g/kg diet exhibited higher final body weight, percent weight gain, and specific growth rate in comparison to the other treatment groups. Whole body proximate composition did not vary among the dietary groups. Intestinal and liver histopathology also indicated no abnormalities. These findings suggest the potential of ascomycetous P. kudriavzevii as a beneficial feed additive in Nile tilapia diets, warranting further investigation into its long-term effects and broader applications in fish culture.

FGF21 Induces Skeletal Muscle Atrophy and Increases Amino Acids in Female Mice: A Potential Role for Glucocorticoids.

Fibroblast growth factor-21 (FGF21) is an intercellular signaling molecule secreted by metabolic organs, including skeletal muscle, in response to intracellular stress. FGF21 crosses the blood-brain barrier and acts via the nervous system to coordinate aspects of the adaptive starvation response, including increased lipolysis, gluconeogenesis, fatty acid oxidation, and activation of the hypothalamic-pituitary-adrenocortical (HPA) axis. Given its beneficial effects for hepatic lipid metabolism, pharmaceutical FGF21 analogues are used in clinical trials treatment of fatty liver disease. We predicted pharmacologic treatment with FGF21 increases HPA axis activity and skeletal muscle glucocorticoid signaling and induces skeletal muscle atrophy in mice. Here we found a short course of systemic FGF21 treatment decreased muscle protein synthesis and reduced tibialis anterior weight; this was driven primarily by its effect in female mice. Similarly, intracerebroventricular FGF21 reduced tibialis anterior muscle fiber cross-sectional area; this was more apparent among female mice than male littermates. In agreement with the reduced muscle mass, the topmost enriched metabolic pathways in plasma collected from FGF21-treated females were related to amino acid metabolism, and the relative abundance of plasma proteinogenic amino acids was increased up to 3-fold. FGF21 treatment increased hypothalamic Crh mRNA, plasma corticosterone, and adrenal weight, and increased expression of glucocorticoid receptor target genes known to reduce muscle protein synthesis and/or promote degradation. Given the proposed use of FGF21 analogues for the treatment of metabolic disease, the study is both physiologically relevant and may have important clinical implications.

[Oculopalpebral trauma in domestic violence]. / Traumatismes oculopalpébraux au cours des violences conjugales.

INTRODUCTION: Oculopalpebral trauma in domestic violence is defined as ophthalmological injuries caused by a spouse. PURPOSE: To describe the epidemiology and management of oculopalpebral injuries caused by domestic violence. PATIENTS AND METHODS: Retrospective descriptive study carried out over a period of 5 years in patients who suffered oculopalpebral trauma from domestic violence. VARIABLES STUDIED: age, sex, profession, visual acuity, blunt instruments, type of injury, treatments. Data processing by Excel 2013 and WPS Office software. RESULTS: We collected 31 patients with a mean age of 34.5±7 years and a sex ratio of 0.3. The most commonly found functional sign was decreased VA in 100% of patients. The mechanism of injury was punching in 71%. Visual acuity was less than 1/20 in 9.7%. Contusion was the most commonly found trauma in 74.19% of cases, and conjunctival hyperemia was seen in 68.2% of cases. Eight patients (25.8%) had undergone surgical treatment. CONCLUSION: Oculopalpebral trauma by domestic violence is serious. Both sexes can be victims. The lesions encountered can affect the functional or even anatomical prognosis of the eye.

Analysis of the Bile Acid Composition in a Fibroblast Growth Factor 19-Expressing Liver-Humanized Mouse Model and Its Use for CYP3A4-Mediated Drug-Drug Interaction Studies.

Numerous biomedical applications have been described for liver-humanized mouse models, such as in drug metabolism or drug-drug interaction (DDI) studies. However, the strong enlargement of the bile acid (BA) pool due to lack of recognition of murine intestine-derived fibroblast growth factor-15 by human hepatocytes and a resulting upregulation in the rate-controlling enzyme for BA synthesis, cytochrome P450 (CYP) 7A1, may pose a challenge in interpreting the results obtained from such mice. To address this challenge, the human fibroblast growth factor-19 (FGF19) gene was inserted into the Fah-/- , Rag2-/- , Il2rg-/- NOD (FRGN) mouse model, allowing repopulation with human hepatocytes capable of responding to FGF19. While a decrease in CYP7A1 expression in human hepatocytes from humanized FRGN19 mice (huFRGN19) and a concomitant reduction in BA production was previously shown, a detailed analysis of the BA pool in these animals has not been elucidated. Furthermore, there are sparse data on the use of this model to assess potential clinical DDI. In the present work, the change in BA composition in huFRGN19 compared with huFRGN control animals was systematically evaluated, and the ability of the model to recapitulate a clinically described CYP3A4-mediated DDI was assessed. In addition to a massive reduction in the total amount of BA, FGF19 expression in huFRGN19 mice resulted in significant changes in the profile of various primary, secondary, and sulfated BAs in serum and feces. Moreover, as observed clinically, administration of the pregnane X receptor agonist rifampicin reduced the oral exposure of the CYP3A4 substrate triazolam. SIGNIFICANCE STATEMENT: Transgenic expression of FGF19 normalizes the unphysiologically high level of bile acids in a chimeric liver-humanized mouse model and leads to massive changes in bile acid composition. These adaptations could overcome one of the potential impediments in the use of these mouse models for drug-drug interaction studies.

FGF21 controls hepatic lipid metabolism via sex-dependent interorgan crosstalk.

The liver regulates energy partitioning and use in a sex-dependent manner, coupling hepatic substrate availability to female reproductive status. Fibroblast growth factor 21 (FGF21) is a hepatokine produced in response to metabolic stress that adaptively directs systemic metabolism and substrate use to reduce hepatic lipid storage. Here we report that FGF21 altered hepatic transcriptional and metabolic responses, and reduced liver triglycerides, in a sex-dependent manner. FGF21 decreased hepatic triglycerides in obese male mice in a weight loss-independent manner; this was abrogated among female littermates. The effect of FGF21 on hepatosteatosis is thought to derive, in part, from increased adiponectin secretion. Accordingly, plasma adiponectin and its upstream adrenergic receptor → cAMP → exchange protein directly activated by cAMP signaling pathway was stimulated by FGF21 in males and inhibited in females. Both ovariectomized and reproductively senescent old females responded to FGF21 treatment by decreasing body weight, but liver triglycerides and adiponectin remained unchanged. Thus, the benefit of FGF21 treatment for improving hepatosteatosis depends on sex but not on a functional female reproductive system. Because FGF21 provides a downstream mechanism contributing to several metabolic interventions, and given its direct clinical importance, these findings may have broad implications for the targeted application of nutritional and pharmacological treatments for metabolic disease.

Fibroblast Growth Factor 21 Facilitates the Homeostatic Control of Feeding Behavior.

Fibroblast growth factor 21 (FGF21) is a stress hormone that is released from the liver in response to nutritional and metabolic challenges. In addition to its well-described effects on systemic metabolism, a growing body of literature now supports the notion that FGF21 also acts via the central nervous system to control feeding behavior. Here we review the current understanding of FGF21 as a hormone regulating feeding behavior in rodents, non-human primates, and humans. First, we examine the nutritional contexts that induce FGF21 secretion. Initial reports describing FGF21 as a 'starvation hormone' have now been further refined. FGF21 is now better understood as an endocrine mediator of the intracellular stress response to various nutritional manipulations, including excess sugars and alcohol, caloric deficits, a ketogenic diet, and amino acid restriction. We discuss FGF21's effects on energy intake and macronutrient choice, together with our current understanding of the underlying neural mechanisms. We argue that the behavioral effects of FGF21 function primarily to maintain systemic macronutrient homeostasis, and in particular to maintain an adequate supply of protein and amino acids for use by the cells.

[Causes of visual impairment among people living with HIV at the University Hospital of Libreville]. / Causes de deficience visuelle chez les personnes vivant avec le VIH/SIDA au CHU de Libreville.

INTRODUCTION: Few data exist on the issue of visual impairment (VI) in people living with HIV (PLHIV). OBJECTIVE: To identify the causes of visual impairment among people living with HIV (PLHIV) at the University Hospital of Libreville. POPULATION AND METHODS: This was an observational study of 737 people living with HIV (PLHIV). The parameters studied were age (year), gender, CD4 count, age of infection, use of antiretroviral therapy as well as visual acuity from far and near (CMI-11) and cause of VI. RESULTS: Out of a population of 737 PLHIV, 75 (101 eyes) had VI, representing a hospital prevalence of 10.2% (n = 75/737). VI was bilateral for 34.7% (n = 26/75) of them. The main aetiology were refractive disorders (47.5%). Uveitis affected 16.8% of the number of eyes, of which 12.9% were of toxoplasmic origin. Other causes were cataracts (11.9%) and cytomegalovirus retinitis (10.9%). Two patients experienced early macular degeneration and two others with macular ischemia. Bilateral macular hemorrhage and occlusion of the central artery of the retina were also observed. CONCLUSION: One in 10 PLHIV is visually impaired. In half of the cases, the pathologies that provide this handicap, are opportunistic disease with ocular toxoplasmosis in the foreground. Routine screening may improve visual prognosis.

INTRODUCTION: Peu de données existent sur la question de la déficience visuelle (DV) chez les personnes vivant avec le VIH (PVVIH). OBJECTIF: Recenser les causes d'insuffisance visuelle chez les personnes vivant avec le VIH (PVVIH) au centre hospitalier universitaire de Libreville. POPULATION ET MÉTHODES: Il s'agissait d'une étude observationnelle réalisée auprès de 737 personnes vivant avec le VIH (PVVIH). Les paramètres étudiés étaient l'âge (année), le sexe, le taux de CD4, l'ancienneté de l'infection, la prise du traitement antirétroviral ainsi que l'acuité visuelle de loin et de près (CMI-11) et la cause de la DV. RÉSULTATS: Sur un effectif de 737 PVVIH, 75 (101 yeux) ont présenté une DV, soit une prévalence hospitalière de 10,2% (n = 75/737). La DV était bilatérale pour 34,7% (n = 26/75) d'entre eux. Les principales étiologies étaient les troubles de la réfraction (47,5%). Les uvéites affectaient16,8% de l'effectif d'yeux dont 12,9% étaient d'origine toxoplasmique. Les autres causes étaient la cataracte (11,9%) et la rétinite à CMV (10,9%). Deux patients ont présenté une dégénérescence maculaire précoce et deux autres une ischémie maculaire. Une hémorragie maculaire bilatérale et une occlusion de l'artère centrale de la rétine étaient également observées. CONCLUSION: Une PVVIH sur 10 est déficiente visuelle. Dans la moitié des cas, les pathologies pourvoyeuses de ce handicap sont les affections opportunistes avec au premier plan la toxoplasmose oculaire. Un dépistage systématique pourrait améliorer le pronostic visuel.

Etude de la variation de l'épaisseur centrale de la cornée au cours d'une hyperglycémie de novo / Study of the variation of the central thickness of the horn during de novo hyperglycemia

Introduction : L'épaisseur centrale de la cornée peut être modifiée au cours d'une hyperglycémie chronique. En dehors d'une hyperglycémie chronique, nous pensons que les modifications de l'épaisseur cornéenne surviennent également lors des hyperglycémies de novo.Objectif: Déterminer la variation de l'épaisseur centrale de la cornée au cours d'une hyperglycémie de novo.Patients et Méthodes : Il s'agissait d'une étude observationnelle et transversale à visée analytique réalisée de juillet à novembre 2021, auprès de 222 personnes (444 yeux) présentant une hyperglycémie récente. L'ECC a été comparée entre le moment du diagnostic (J0) et 30 jours (J30) après l'initiation du traitement hypoglycémiant (Chi-2). La variation de l'ECC entre J0 et J30 a été corrélée à celle de la glycémie (Spearman ; p<0,05).Résultats : A J0, la moyenne de l'ECC était de 552,5±39,2 µm contre 538,0±34,2 µm à J30 (p=0,001) et celle de la glycémie de 18,1±8,2 mmo/L contre 6,9±3,0 mmol/L (p = 0,001). A J0, 57,0% avaient une ECC > 550µm et à J30, 19,4% avaient diminué cette épaisseur entre 520 et 550 µm et 3,4% à moins de 520 µm. Sur un effectif de 444 yeux, 28,2% (n = 125) ont diminué leur ECC de 25 µm et plus après initiation du traitement hypoglycémiant. Aucune corrélation n'existait entre la variation de l'ECC et celle de la glycémie (r=0,018; p=0,704).Conclusion : Ces résultats montrent qu'il existe une variation de l'ECC en cas de déséquilibre glycémique récent

Introduction : The central thickness of the cornea can be changed during chronic hyperglycemia. Apart from chronic hyperglycemia, we believe that changes in corneal thickness also occur during de novo hyperglycemia.Objective: To determine the variation in the central thickness of the cornea during de novo hyperglycemia.Patients and Methods: This was an observational and cross-sectional analytical study conducted from July to November 2021, involving 222 people (444 eyes) with recent hyperglycemia. ECC was compared between the time of diagnosis (D0) and 30 days (Day 30) after initiation of hypoglycemic (Chi-2) therapy. The change in ECC between J0 and J30 was correlated with that of blood glucose (Spearman ; p<0,05).Results: ON D0, the mean ECC was 552.5±39.2 µm versus 538.0± 34.2 µm on D30 ( p=0.001) and the blood glucose mean was 18.1±8.2 mmo/l versus 6.9±3.0 mmol/l ( p=0.001). On D0, 57.0% had an ECC ˃ 550µm and on D30, 19.4% had decreased this thickness between 520 and 550 µm and 3.4% to less than 520 µm. On a population of 444 eyes, 28.2% ( n=125) decreased their ECC by 25 µm and more after initiation of hypoglycemic therapy. There was no correlation between the change in ECC and the change in blood glucose (r=0.018; p=0.704).Conclusion : These results show that there is a variation in ECC in case of recent glycemic imbalance

PBPK Modeling as a Tool for Predicting and Understanding Intestinal Metabolism of Uridine 5'-Diphospho-glucuronosyltransferase Substrates.

Uridine 5'-diphospho-glucuronosyltransferases (UGTs) are expressed in the small intestines, but prediction of first-pass extraction from the related metabolism is not well studied. This work assesses physiologically based pharmacokinetic (PBPK) modeling as a tool for predicting intestinal metabolism due to UGTs in the human gastrointestinal tract. Available data for intestinal UGT expression levels and in vitro approaches that can be used to predict intestinal metabolism of UGT substrates are reviewed. Human PBPK models for UGT substrates with varying extents of UGT-mediated intestinal metabolism (lorazepam, oxazepam, naloxone, zidovudine, cabotegravir, raltegravir, and dolutegravir) have demonstrated utility for predicting the extent of intestinal metabolism. Drug-drug interactions (DDIs) of UGT1A1 substrates dolutegravir and raltegravir with UGT1A1 inhibitor atazanavir have been simulated, and the role of intestinal metabolism in these clinical DDIs examined. Utility of an in silico tool for predicting substrate specificity for UGTs is discussed. Improved in vitro tools to study metabolism for UGT compounds, such as coculture models for low clearance compounds and better understanding of optimal conditions for in vitro studies, may provide an opportunity for improved in vitro-in vivo extrapolation (IVIVE) and prospective predictions. PBPK modeling shows promise as a useful tool for predicting intestinal metabolism for UGT substrates.

Hydrothermotherapy in prevention and treatment of mild to moderate cases of COVID-19.

COVID-19 is a new contagious disease caused by a new coronavirus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 is a disease that has reached every continent in the world; it has overloaded the medical system worldwide and it has been declared a pandemic by the World Health Organization. Currently there is no definite treatment for COVID-19. We realize that host immunity is a critical factor in the outcome of coronavirus 2 infection. Here, however, we review the pathophysiology of the disease with a focus on searching for what we can do to combat this new disease. From this, we find that coronavirus is sensitive to heat. We have thus focused on this area of vulnerability of the virus. The emphasis of this hypothesis is on the action of body heat-internal (fever) and external (heat treatment)-in activating the immune system and its antiviral activities, and specifically related to the coronavirus. We hypothesize from this review that heat treatments has the potential to prevent COVID-19 and to decrease the severity of mild and moderate cases of Coronavirus. We propose heat treatments for this uncontrolled worldwide coronavirus pandemic while studies are being done to test the effectiveness of heat treatments in the prevention and treatment of COVID-19.

Physiologically based pharmacokinetic modelling of oxycodone drug-drug interactions.

Oxycodone is an opioid analgesic with several pharmacologically active metabolites and relatively narrow therapeutic index. Cytochrome P450 (CYP) 3A4 and CYP2D6 play major roles in the metabolism of oxycodone and its metabolites. Thus, inhibition and induction of these enzymes may result in substantial changes in the exposure of both oxycodone and its metabolites. In this study, a physiologically based pharmacokinetic (PBPK) model was built using GastroPlus™ software for oxycodone, two primary metabolites (noroxycodone, oxymorphone) and one secondary metabolite (noroxymorphone). The model was built based on literature and in house in vitro and in silico data. The model was refined and verified against literature clinical data after oxycodone administration in the absence of drug-drug interactions (DDI). The model was further challenged with simulations of oxycodone DDI with CYP3A4 inhibitors ketoconazole and itraconazole, CYP3A4 inducer rifampicin and CYP2D6 inhibitor quinidine. The magnitude of DDI (AUC ratio) was predicted within 1.5-fold error for oxycodone, within 1.8-fold and 1.3-4.5-fold error for the primary metabolites noroxycodone and oxymorphone, respectively, and within 1.4-4.5-fold error for the secondary metabolite noroxymorphone, when compared to the mean observed AUC ratios. This work demonstrated the capability of PBPK model to simulate DDI of the administered compounds and the formed metabolites of both DDI victim and perpetrator. However, the predictions for the formed metabolites tend to be associated with higher uncertainty than the predictions for the administered compound. The oxycodone model provides a tool for forecasting oxycodone DDI with other CYP3A4 and CYP2D6 DDI perpetrators that may be co-administered with oxycodone.

In vitro glucuronidation of 7-hydroxycoumarin derivatives in intestine and liver microsomes of Beagle dogs.

Beagle dog is a standard animal model for evaluating nonclinical pharmacokinetics of new drug candidates. Glucuronidation in intestine and liver is an important first-pass drug metabolic pathway, especially for phenolic compounds. This study evaluated the glucuronidation characteristics of several 7-hydroxycoumarin derivatives in beagle dog's intestine and liver in vitro. To this end, glucuronidation rates of 7-hydroxycoumarin (compound 1), 7-hydroxy-4-trifluoromethylcoumarin (2), 6-methoxy-7-hydroxycoumarin (3), 7-hydroxy-3-(4-tolyl)coumarin (4), 3-(4-fluorophenyl)coumarin (5), 7-hydroxy-3-(4-hydroxyphenyl)coumarin (6), 7-hydroxy-3-(4-methoxyphenyl)coumarin (7), and 7-hydroxy-3-(1H-1,2,4-tirazole)coumarin (8) were determined in dog's intestine and liver microsomes, as well as recombinant dog UGT1A enzymes. The glucuronidation rates of 1, 2 and 3 were 3-10 times higher in liver than in small intestine microsomes, whereas glucuronidation rates of 5, 6, 7 and 8 were similar in microsomes from both tissues. In the colon, glucuronidation of 1 and 2 was 3-5 times faster than in small intestine. dUGT1A11 glucuronidated efficiently all the substrates and was more efficient catalyst for 8 than any other dUGT1A. Other active enzymes were dUGT1A2 that glucuronidated efficiently 2, 3, 4, 5, 6 and 7, while dUGT1A10 glucuronidated efficiently 1, 2, 3, 4, 5 and 7. Kinetic analyses revealed that the compounds' Km values varied between 1.1 (dUGT1A10 and 2) and 250 µM (dUGT1A7 and 4). The results further strengthen the concept that dog intestine has high capacity for glucuronidation, and that different dUGT1As mediate glucuronidation with distinct substrates selectivity in dog and human.

Epidémiologie et prise en charge du zona ophtalmique à l'Hôpital d'Instruction des Armées Omar Bongo Ondimba (HIA OBO), à Libreville, au Gabon

Introduction: Le virus de la varicelle et du zonaest à l'origine d'un large spectre d'atteintes systémiques et oculaires.Le but de ce travail est de montrer la place de l'ophtalmologiste dans la prise en charge du zona ophtalmique.Matériel et méthodes : Il s'agit d'une étude rétrospective menée dans le service d'Ophtalmologie de l'HIA OBO entre 2016 et 2018, sur une série de patients, pris en charge pour zona ophtalmique.Résultats: Nous avons recruté 8 patients, dont 6 femmes.L'âge moyen était de 42,5 ans. Quatre patients étaient VIH (+). Tous nos patients avaient une cellulite orbitaire. La motilité oculaire était conservée chez tous les patients.L'acuité visuelle était basse chez la plupart. L'examen à la lampe à fente retrouvait une hyperhémie conjonctivale, un chémosis et une atteinte cornéenne. Tous nos patients ont bénéficié d'une bi-antibiothérapie, des antalgiques et des anti-viraux. L'évolution était marquée par la régression de la cellulite orbitaire, la cicatrisation cutanée, la récupération visuelle.Conclusion: Le zona ophtalmique est plus fréquent chez les sujets atteints de VIH, par rapport à la population générale. Correctement pris en charge, son évolution est favorable. Par contre, en l'absence de traitement antiviral, il s'accompagne de complications oculaires dans 50 à 70 % des cas

Growth and fatty acid profiles of Halophytophthora vesicula and Salispina spinosa from Philippine mangrove leaves.

Studies on marine-sourced fatty acids have gathered significant interest recently as an important component of aquaculture feeds and of biofuel production. Of the organisms capable of producing fatty acids, marine oomycetes are promising model organisms. One group of marine oomycetes are the Halophytophthora spp. which is known to have an important role in leaf decomposition, thereby changing the plant debris into exudates which are usable to consumers in the mangrove ecosystems. This study reports the three mangrove oomycetes isolated from Philippine mangrove forests, identified herein as Halophytophthora vesicula AK1YB2 (Aklan), H. vesicula PQ1YB3 (Quezon) and Salispina spinosa ST1YB3 (Davao del Norte). These isolates were subjected to growth analyses using varying incubation parameters (salinity level and pH), and for fatty acid production. Results revealed the presence of different fatty acids such as Arachidonic acid, Linoleic acid and Vaccenic acid when grown on V8S and PYGS media. This study is the first observation of fatty acids from S. spinosa and H. vesicula from the Philippines. SIGNIFICANCE AND IMPACT OF THE STUDY: Tropical Philippines straddling west of the Pacific Ocean and East of South China Sea is rich in marine and estuarine oomycetes. These micro-organisms, hitherto poorly known and unstudied in the country, play an important role in the nutritive cycle of the mangrove ecosystem. Due to the increasing demand for an alternative source of fatty acids, species of Oomycetes isolated from select mangrove forests in Luzon, Visayas and Mindanao were analysed for their fatty acid contents. Prospects for industrially-important fatty acids make these Oomycetes all-important to study in applied microbiology in the Philippine setting where these structurally simple micro-organisms abound.

Sex-dependent effects of MC4R genotype on HPA axis tone: implications for stress-associated cardiometabolic disease.

The melanocortin-4 receptor (MC4R) facilitates hypothalamic-pituitary-adrenocortical (HPA) axis responses to acute stress in male rodents and is a well known to regulator of energy balance. Mutations in the MC4R is the most common monogenic cause of obesity in humans and has been associated with sex-specific effects, but whether stress regulation by the MC4R is sex-dependent, and whether the MC4R facilitates HPA responses to chronic stress, is unknown. We hypothesized that MC4R-signaling contributes to HPA axis dysregulation and metabolic pathophysiology following chronic stress exposure. We measured changes in energy balance, HPA axis tone, and vascular remodeling during chronic variable stress (CVS) in male and female rats with MC4R loss-of-function. Rats were placed into three groups (n = 9-18/genotype/sex) and half of each group was subjected to CVS for 30 days or were non-stressed littermate controls. All rats underwent an acute restraint stress challenge on Day 30. Rats were euthanized on Day 31, adrenals collected for weight, and descending aortas fixed for morphological indices of vascular pathophysiology. We observed a marked interaction between Mc4r genotype and sex for basal HPA axis tone and acute stress responsivity. MC4R loss-of-function blunted both endpoints in males but exaggerated them in females. Contrary to our hypothesis, Mc4r genotype had no effect on either HPA axis responses or metabolic responses to chronic stress. Heightened stress reactivity of females with MC4R mutations suggests a possible mechanism for the sex-dependent effects associated with this mutation in humans and highlights how stress may differentially regulate metabolism in males and females. Lay summary The hypothalamic melanocortin system is an important regulator of energy balance and stress responses. Here, we report a sex-difference in the stress reactivity of rats with a mutation in this system. Our findings highlight how stress may regulate metabolism differently in males and females and may provide insight into sex-differences associated with this mutation in humans.

Fibroblast Growth Factor-21 Controls Dietary Protein Intake in Male Mice.

Whereas carbohydrates and lipids are stored as glycogen and fat, there is no analogous inert storage form of protein. Therefore, continuous adjustments in feeding behavior are needed to match amino acid supply to ongoing physiologic need. Neuroendocrine mechanisms facilitating this behavioral control of protein and amino acid homeostasis remain unclear. The hepatokine fibroblast growth factor-21 (FGF21) is well positioned for such a role, as it is robustly secreted in response to protein and/or amino acid deficit. In this study, we tested the hypothesis that FGF21 feeds back at its receptors in the nervous system to shift macronutrient selection toward protein. In a series of behavioral tests, we isolated the effect of FGF21 to influence consumption of protein, fat, and carbohydrate in male mice. First, we used a three-choice pure macronutrient-diet paradigm. In response to FGF21, mice increased consumption of protein while reducing carbohydrate intake, with no effect on fat intake. Next, to determine whether protein or carbohydrate was the primary-regulated nutrient, we used a sequence of two-choice experiments to isolate the effect of FGF21 on preference for each macronutrient. Sweetness was well controlled by holding sucrose constant across the diets. Under these conditions, FGF21 increased protein intake, and this was offset by reducing the consumption of either carbohydrate or fat. When protein was held constant, FGF21 had no effect on macronutrient intake. Lastly, the effect of FGF21 to increase protein intake required the presence of its co-receptor, ß-klotho, in neurons. Taken together, these findings point to a novel liver→nervous system pathway underlying the regulation of dietary protein intake via FGF21.

Physiologically Based Pharmacokinetic Modelling for First-In-Human Predictions: An Updated Model Building Strategy Illustrated with Challenging Industry Case Studies.

Physiologically based pharmacokinetic modelling is well established in the pharmaceutical industry and is accepted by regulatory agencies for the prediction of drug-drug interactions. However, physiologically based pharmacokinetic modelling is valuable to address a much wider range of pharmaceutical applications, and new regulatory impact is expected as its full power is leveraged. As one example, physiologically based pharmacokinetic modelling is already routinely used during drug discovery for in-vitro to in-vivo translation and pharmacokinetic modelling in preclinical species, and this leads to the application of verified models for first-in-human pharmacokinetic predictions. A consistent cross-industry strategy in this application area would increase confidence in the approach and facilitate further learning. With this in mind, this article aims to enhance a previously published first-in-human physiologically based pharmacokinetic model-building strategy. Based on the experience of scientists from multiple companies participating in the GastroPlus™ User Group Steering Committee, new Absorption, Distribution, Metabolism and Excretion knowledge is integrated and decision trees proposed for each essential component of a first-in-human prediction. We have reviewed many relevant scientific publications to identify new findings and highlight gaps that need to be addressed. Finally, four industry case studies for more challenging compounds illustrate and highlight key components of the strategy.

Metabolism of Scoparone in Experimental Animals and Humans.

Scoparone, a major constituent of the Chinese herbal medicine Yin Chen Hao, expresses beneficial effects in experimental models of various diseases. The intrinsic doses and effects of scoparone are dependent on its metabolism, both in humans and animals. We evaluated in detail the metabolism of scoparone in human, mouse, rat, pig, dog, and rabbit liver microsomes in vitro and in humans in vivo. Oxidation of scoparone to isoscopoletin via 6-O-demethylation was the major metabolic pathway in liver microsomes from humans, mouse, rat, pig and dog, whereas 7-O-demethylation to scopoletin was the main reaction in rabbit. The scoparone oxidation rates in liver microsomes were 0.8 - 1.2 µmol/(min*g protein) in mouse, pig, and rabbit, 0.2 - 0.4 µmol/(min*g protein) in man and dog, and less than 0.1 µmol/(min*g) in rat. In liver microsomes of all species, isoscopoletin was oxidized to 3-[4-methoxy-ρ-(3, 6)-benzoquinone]-2-propenoate and esculetin, which was formed also in the oxidation of scopoletin. Human CYP2A13 exhibited the highest rate of isoscopoletin and scopoletin oxidation, followed by CYP1A1 and CYP1A2. Glucuronidation of isoscopoletin and scopoletin was catalyzed by the human UGT1A1, UGT1A6, UGT1A7, UGT1A8, UGT1A9, UGT1A10, and UGT2B17. Dog was most similar to man in scoparone metabolism. Isoscopoletin glucuronide and sulfate conjugates were the major scoparone in vivo metabolites in humans, and they were completely excreted within 24 h in urine. Scoparone and its metabolites did not activate key nuclear receptors regulating CYP and UGT enzymes. These results outline comprehensively the metabolic pathways of scoparone in man and key preclinical animal species.