Hyperbaric oxygen treatment increases intestinal stem cell proliferation through the mTORC1/S6K1 signaling pathway in Mus musculus.

BACKGROUND: Hyperbaric oxygen treatment (HBOT) has been reported to modulate the proliferation of neural and mesenchymal stem cell populations, but the molecular mechanisms underlying these effects are not completely understood. In this study, we aimed to assess HBOT somatic stem cell modulation by evaluating the role of the mTOR complex 1 (mTORC1), a key regulator of cell metabolism whose activity is modified depending on oxygen levels, as a potential mediator of HBOT in murine intestinal stem cells (ISCs). RESULTS: We discovered that acute HBOT synchronously increases the proliferation of ISCs without affecting the animal's oxidative metabolism through activation of the mTORC1/S6K1 axis. mTORC1 inhibition by rapamycin administration for 20 days also increases ISCs proliferation, generating a paradoxical response in mice intestines, and has been proposed to mimic a partial starvation state. Interestingly, the combination of HBOT and rapamycin does not have a synergic effect, possibly due to their differential impact on the mTORC1/S6K1 axis. CONCLUSIONS: HBOT can induce an increase in ISCs proliferation along with other cell populations within the crypt through mTORC1/S6K1 modulation without altering the oxidative metabolism of the animal's small intestine. These results shed light on the molecular mechanisms underlying HBOT therapeutic action, laying the groundwork for future studies.

COVID-19: Abdominal and Pelvic Imaging Findings: A Primer for Radiologists.

ABSTRACT: The COVID-19 pandemic presents an ongoing global health threat. The SARS-CoV-2 is known to cause substantial pulmonary disease, and most of the current radiological publications are dedicated to describing and characterizing these findings. However, studies regarding imaging findings in the abdomen and pelvis of infected patients are still very limited. The aim of this review is to discuss the most frequent abdominal manifestations based on the current literature and representative images from our local experience.

Recognizing the Ultrasound Patterns of Mesenteric Panniculitis.

ABSTRACT: Mesenteric panniculitis (MP) is a rare, benign, and nonspecific chronic fibrosing inflammation of the mesenteric adipose tissue. Abdominal pain is the most frequent presentation.The objective was to recognize ultrasound (US) features in MP. A retrospective 9-year review of computed tomography- (CT) or US-diagnosed cases of MP recorded in the radiology department was performed. The inclusion criteria included an US recorded in PACS imaging data base within 10 days before CT, to compare and evaluate the correlation of MP diagnosis.The prevalence of MP on CT was 2.8%. The 120 selected patients had an abdominal US 10 days before CT. Male-to-female ratio was 4:1. Fifty-three percent of MP was suggested by US. The US finding was increased volume with fatty mass in the mesentery root (98%). The fatty mesenteric mass had oval shape or convex anterior border in 94%, central abdominal location in 91%, and focal mesenteric increased echogenicity in 95%. Lateral bowel loop displacement was observed in 59%. Detection of lymph nodes was less frequent (55%).In conclusion, MP is an entity to be considered in the differential diagnosis of abdominal pain. Knowledge and recognition of the US findings of MP and central abdominal compression may improve detection during the abdominal US examination.

The interplay between exposure to PAHs and MTHFR C677T polymorphism on cardiovascular risk biomarkers in Mexican women.

Cardiovascular diseases (CVDs) are the leading cause of morbidity and mortality worldwide. Environmental and genetic factors are recognized as risk determinants in the onset and development of CVDs. However, the interaction between both factors on CVDs risk is not still completely clarified. Therefore, the objective of this study was to evaluate the effect of the interaction between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and polycyclic aromatic hydrocarbon (PAH) exposure (gene-environment interaction) on cardiovascular risk biomarkers in Mexican women. A cross-sectional study was completed with the participation of 390 healthy women. For all enrolled women, anthropometric measurements, serum biochemical analyses, atherogenic indexes, and serum concentrations of biomolecules used as CVD risk biomarkers were obtained. 1-Hydroxypyrene (1-OHP) was measured in urine, as an exposure biomarker of PAHs. The mean urinary level of 1-OHP in the assessed population was 1.23 ± 1.40 µmol/mol creatinine. The allelic frequency (MTHFR C677T polymorphism) identified in the registered individuals was 68.0% for the mutant allele (T-allele). Significant positive associations were detected between urinary 1-OHP levels and serum asymmetric dimethylarginine (ADMA) concentrations (p < 0.05) and atherogenic index of plasma (AIP) values (p < 0.05). Also, women with the TT genotype of the MTHFR C677T enzyme have the highest serum ADMA levels (p < 0.05) and AIP values (p < 0.05) compared to women grouped as CC genotype and CT genotype. Besides, the findings in this study suggest an interaction between environmental (PAHs exposure) and genetic (MTHFR C677T polymorphism) factors on cardiovascular risk markers (ADMA and AIP). According to the usefulness of AIP and ADMA, an increased cardiovascular risk is notable in highly exposed individuals to PAHs with the polymorphic genotype (TT) of the MTHFR enzyme. Therefore, intervention programs in the target communities are required to diminish the cardiovascular risk of the assessed individuals.

Acute Pancreatitis Imaging in MDCT: State of the Art of Usual and Unusual Local Complications. 2012 Atlanta Classification Revisited.

Acute pancreatitis is an inflammatory disease in which most common etiologies are biliary lithiasis and alcoholism. Acute pancreatitis can be classified into 2 groups according to its morphologic features: interstitial edematous pancreatitis and necrotizing acute pancreatitis. The prognosis of this group of diseases and its complications varies significantly and contrast-enhanced computed tomography is the imaging study of choice for the diagnosis and detection of complications. . In this review, we aim to summarize the changes introduced in the revised Atlanta classification and describe other usual and unusual local complications of acute pancreatitis that are not analyzed in that classification. We will also describe early detection signs and provide an accurate interpretation of complications on contrast-enhanced computed tomography that will lead to prompt management decisions which can reduce the morbidity and mortality of these patients.

Costs of exploratory behavior: the energy trade-off hypothesis and the allocation model tested under caloric restriction.

In order to maintain the energy balance, animals often exhibit several physiological adjustments when subjected to a decrease in resource availability. Specifically, some rodents show increases in behavioral activity in response to food restriction; a response regarded as a paradox because it would imply an investment in locomotor activity, despite the lack of trophic resources. Here, we aim to explore the possible existence of trade-offs between metabolic variables and behavioral responses when rodents are faced to stochastic deprivation of food and caloric restriction. Adult BALB/c mice were acclimatized for four weeks to four food treatments: two caloric regimens (ad libitum and 60% restriction) and two periodicities (continuous and stochastic). In these mice, we analyzed: exploratory behavior and home-cage behavior, basal metabolic rate, citrate synthase and cytochrome oxidase c enzyme activity (in liver and skeletal muscle), body temperature and non-shivering thermogenesis. Our results support the model of allocation, which indicates commitments between metabolic rates and exploratory behavior, in a caloric restricted environment. Specifically, we identify the role of thermogenesis as a pivotal budget item, modulating the reallocation of energy between behavior and basal metabolic rate. We conclude that brown adipose tissue and liver play a key role in the development of paradoxical responses when facing decreased dietary availability.

Multimodality Imaging of Congenital Variants in the Gallbladder: Pictorial Essay.

Congenital variants of the gallbladder development are infrequent and sometimes represent an asymptomatic imaging finding. In this case series, we want to present multimodality imaging findings that permit the diagnosis. Ultrasound, multidetector computed tomography, and magnetic resonance images are included.The proper recognition of these infrequent congenital benign entities avoids unnecessary complementary examinations and misdiagnosis. Although ultrasound represents the most commonly used initial diagnostic tool, the increased use of magnetic resonance imaging and the wide use of multidetector computed tomography make it crucial to know how these entities are seen.A retrospective review of cases of congenital variants of gallbladder through different imaging modalities was performed in our computer archives. Representative images were selected. Agenesis, hypoplasia, septated, duplicated, intrahepatic, and left-sided gallbladder are described.Better understanding and recognition of congenital anomalies in gallbladder images will avoid misdiagnosis.

Adaptive Physiological and Morphological Adjustments Mediated by Intestinal Stem Cells in Response to Food Availability in Mice.

Several studies have evaluated plastic changes in the morphology of the digestive tract in rodents subjected to caloric restriction or restricted availability. Nevertheless, studies that link these morphological responses to physiological consequences are scarce. In order to investigate short-term plastic responses in the intestine, we acclimated adult Mus musculus (BALB/c) males for 20 days to four distinctive treatments: two caloric regimens (ad libitum and 60% of calorie ingestion) and two levels of periodicity of the regimens (continuous and stochastic treatment). At the end of the treatment we analyzed the cell proliferation and cell death dynamics of small intestinal crypts in these animals. In addition, we measured organ masses and lengths, hydrolytic digestive enzyme activities, and energy output from feces. Finally, in order to explore the metabolic changes generated by these dietary conditions we assessed the catabolic activity (i.e., enzymes) of the liver. Our results show that individuals acclimated to a continuous and 60% regimen presented longer intestines in comparison to the other treatments. Indeed, their intestines grew with a rate of 0.22 cm/day, generating a significant caloric reduction in the content of their feces. Besides, both mass and intestinal lengths were predicted strongly by the stabilization coefficient of BrdU+ proliferating cells per crypt, the latter correlating positively with the activity of n-aminopeptidases. Interestingly, by using pharmacological inhibition of the kinase mammalian target of rapamycin complex 1 (mTORC1) by Rapamycin, we were able to recapitulate similar changes in the proliferation dynamics of intestinal stem cells. Based on our results, we propose that the impact of caloric restriction on macroscopic variation in morphology and functional changes in digestive n-aminopeptidases occurs through synchronization in the proliferation rate of stem and/or progenitor cells located in the small intestinal crypts and requires mTORC1 as a key mediator. Hence, we suggest that an excessive stem and progenitor activity could result in increased crypts branching and might therefore underlie the reported intestinal tissue expansion in response to short-term caloric restriction. Summarizing, we demonstrate for the first time that short-term caloric restriction induces changes in the level of cell proliferation dynamics explaining in part digestive tract plasticity in adaptive performance.

Hyperbaric Oxygen Increases Stem Cell Proliferation, Angiogenesis and Wound-Healing Ability of WJ-MSCs in Diabetic Mice.

Hyperbaric oxygen therapy (HBOT) is effective for the medical treatment of diverse diseases, infections, and tissue injury. In fact, in recent years there is growing evidence on the beneficial effect of HBOT on non-healing ischemic wounds. However, there is still yet discussion on how this treatment could benefit from combination with regenerative medicine strategies. Here we analyzed the effects of HBOT on three specific aspects of tissue growth, maintenance, and regeneration: (i) modulation of adult rodent (Mus musculus) intestinal stem cell turnover rates; (ii) angiogenesis dynamics during the development of the chorio-allantoic membrane (CAM) in Gallus gallus embryos; (iii) and wound-healing in a spontaneous type II diabetic mouse model with a low capacity to regenerate skin. To analyze these aspects of tissue growth, maintenance, and regeneration, we used HBOT alone or in combination with cellular therapy. Specifically, Wharton Jelly Mesenchymal Stem cells (WJ-MSC) were embedded in a commercial collagen-scaffold. HBOT did not affect the metabolic rate of adult mice nor of chicken embryos. Notwithstanding, HBOT modified the proliferation rate of stem cells in the mice small intestinal crypts, increased angiogenesis in the CAM, and improved wound-healing and tissue repair in diabetic mice. Moreover, our study demonstrates that combining stem cell therapy and HBOT has a collaborative effect on wound-healing. In summary, our data underscore the importance of oxygen tension as a regulator of stem cell biology and support the potential use of oxygenation in clinical treatments.