Gender-based heterogeneity of FAHFAs in trained runners.

Fatty acid esters of hydroxy fatty acid (FAHFA) are anti-diabetic and anti-inflammatory lipokines. Recently FAHFAs were also found to predict cardiorespiratory fitness in a cross-sectional study of recreationally trained runners. Here we report the influences of body composition and gender on static FAHFA abundances in circulation. We compared the association between circulating FAHFA concentrations and body composition, determined by dual x-ray absorptiometry, in female recreational runners who were lean (BMI < 25 kg/m2, n = 6), to those who were overweight (BMI ≥ 25 kg/m2, n = 7). To characterize the effect of gender we also compared circulating FAHFAs in lean male recreational runners (n = 8) to recreationally trained lean female (n = 6) runner group. Circulating FAHFAs were increased in females in a manner that was modulated by specific adipose depot sizes, blood glucose, and lean body mass. As expected, circulating FAHFAs were diminished in the overweight group, but strikingly, within the lean cohort, increases in circulating FAHFAs were promoted by increased fat mass, relative to lean mass, while the overweight group showed a significantly attenuated relationship. These studies suggest multimodal regulation of circulating FAHFAs and raise hypotheses to test endogenous FAHFA dynamic sources and sinks in health and disease, which will be essential for therapeutic target development. Baseline circulating FAHFA concentrations could signal sub-clinical metabolic dysfunction in metabolically healthy obesity.

Novel species of Triatoma (Hemiptera: Reduviidae) identified in a case of vectorial transmission of Chagas disease in northern Belize.

Chagas disease is a leading cause of non-ischemic cardiomyopathy in endemic regions of Central and South America. In Belize, Triatoma dimidiata sensu lato has been identified as the predominate taxon but vectorial transmission of Chagas disease is considered to be rare in the country. We recently identified an acute case of vector-borne Chagas disease in the northern region of Belize. Here we present a subsequent investigation of triatomines collected around the case-patient's home. We identified yet undescribed species, closely related to Triatoma huehuetenanguensis vector by molecular systematics methods occurring in the peridomestic environment. The identification of a T. cruzi-positive, novel species of Triatoma in Belize indicates an increased risk of transmission to humans in the region and warrants expanded surveillance and further investigation.

Metabolic Messengers: ketone bodies.

Prospective molecular targets and therapeutic applications for ketone body metabolism have increased exponentially in the past decade. Initially considered to be restricted in scope as liver-derived alternative fuel sources during periods of carbohydrate restriction or as toxic mediators during diabetic ketotic states, ketogenesis and ketone bodies modulate cellular homeostasis in multiple physiological states through a diversity of mechanisms. Selective signalling functions also complement the metabolic fates of the ketone bodies acetoacetate and D-ß-hydroxybutyrate. Here we discuss recent discoveries revealing the pleiotropic roles of ketone bodies, their endogenous sourcing, signalling mechanisms and impact on target organs, and considerations for when they are either stimulated for endogenous production by diets or pharmacological agents or administered as exogenous wellness-promoting agents.

Review of Toxocariasis at a Children's Hospital Prompting Need for Public Health Interventions.

BACKGROUND: Toxocariasis, caused the by dog and cat roundworm, is one of the most common zoonotic helminth infections in the United States and can lead to severe lifelong morbidity in children. Although historical seroprevalence studies have identified a high frequency of toxocariasis regionally in the United States, there are few studies linking epidemiology and clinical disease in children. The study objective was to examine the contemporary epidemiology of pediatric toxocariasis within an endemic US region. METHODS: We conducted an epidemiologic study analyzing children diagnosed with toxocariasis presenting to a tertiary pediatric hospital in Texas from 2010 to 2021. We examined risk factors and performed a geospatial analysis, including a comparative analysis of human cases and locations of surrendered infected stray animals in the same region. RESULTS: Children diagnosed with toxocariasis were most commonly of Hispanic/Latino ethnicity (30/46; 65%), white race (41/45; 91%) and receiving Medicaid (34/44, 77%). Many infected children had contact with dogs or cats. Ocular toxocariasis was associated with a lack of peripheral eosinophilia ( P < 0.001). No other Toxocara syndromes were associated with defined absolute eosinophil count levels. Post-treatment resolution of eosinophilia was variable, ranging from 1 to 172 weeks. A Toxocara hotspot was identified in northeast Houston, comprising one of the lowest median household incomes in the region. CONCLUSIONS: Toxocariasis is a devastating zoonotic infection in children living in the US. As it is not a reportable disease, the true burden remains unknown. It is critical to increase awareness of toxocariasis to direct public health interventions and ultimately reduce Toxocara -induced morbidity in US children.

Gender-based heterogeneity of FAHFAs in trained runners.

Fatty acid esters of hydroxy fatty acid (FAHFA) are anti-diabetic and anti-inflammatory lipokines. Recently FAHFAs were also found to predict cardiorespiratory fitness in trained runners. Here we compared the association between circulating FAHFA baseline concentrations and body composition, determined by dual x-ray absorptiometry, in female runners who were lean (BMI < 25 kg/m2, n = 6), to those who were overweight (BMI ≥ 25 kg/m2, n = 7). We also compared circulating FAHFAs in lean male runners (n = 8) to the same trained lean female (n = 6) runner group. Circulating FAHFAs were increased in females in a manner that was modulated by specific adipose depot sizes, blood glucose, and lean body mass. As expected, circulating FAHFAs were diminished in the overweight group, but, strikingly, in both lean and overweight cohorts, increases in circulating FAHFAs were promoted by increased fat mass, relative to lean mass. These studies suggest multimodal regulation of circulating FAHFAs and raise hypotheses to test endogenous FAHFA dynamic sources and sinks in health and disease, which will be essential for therapeutic target development. Baseline circulating FAHFA concentrations could signal sub-clinical metabolic dysfunction in metabolically healthy obesity.

Metformin impairs trophoblast metabolism and differentiation in a dose-dependent manner.

Metformin is a widely prescribed medication whose mechanism of action is not completely defined and whose role in gestational diabetes management remains controversial. In addition to increasing the risk of fetal growth abnormalities and preeclampsia, gestational diabetes is associated with abnormalities in placental development including impairments in trophoblast differentiation. Given that metformin impacts cellular differentiation events in other systems, we assessed metformin's impact on trophoblast metabolism and differentiation. Using established cell culture models of trophoblast differentiation, oxygen consumption rates and relative metabolite abundance were determined following 200 µM (therapeutic range) and 2000 µM (supra-therapeutic range) metformin treatment using Seahorse and mass-spectrometry approaches. While no differences in oxygen consumption rates or relative metabolite abundance were detected between vehicle and 200 µM metformin-treated cells, 2000 µM metformin impaired oxidative metabolism and increased the abundance of lactate and TCA cycle intermediates, α-ketoglutarate, succinate, and malate. Examining differentiation, treatment with 2000 µM, but not 200 µM metformin, impaired HCG production and expression of multiple trophoblast differentiation markers. Overall, this work suggests that supra-therapeutic concentrations of metformin impair trophoblast metabolism and differentiation whereas metformin concentrations in the therapeutic range do not strongly impact these processes.

Mitochondrial citrate metabolism and efflux regulate BeWo differentiation.

Cytotrophoblasts fuse to form and renew syncytiotrophoblasts necessary to maintain placental health throughout gestation. During cytotrophoblast to syncytiotrophoblast differentiation, cells undergo regulated metabolic and transcriptional reprogramming. Mitochondria play a critical role in differentiation events in cellular systems, thus we hypothesized that mitochondrial metabolism played a central role in trophoblast differentiation. In this work, we employed static and stable isotope tracing untargeted metabolomics methods along with gene expression and histone acetylation studies in an established BeWo cell culture model of trophoblast differentiation. Differentiation was associated with increased abundance of the TCA cycle intermediates citrate and α-ketoglutarate. Citrate was preferentially exported from mitochondria in the undifferentiated state but was retained to a larger extent within mitochondria upon differentiation. Correspondingly, differentiation was associated with decreased expression of the mitochondrial citrate transporter (CIC). CRISPR/Cas9 disruption of the mitochondrial citrate carrier showed that CIC is required for biochemical differentiation of trophoblasts. Loss of CIC resulted in broad alterations in gene expression and histone acetylation. These gene expression changes were partially rescued through acetate supplementation. Taken together, these results highlight a central role for mitochondrial citrate metabolism in orchestrating histone acetylation and gene expression during trophoblast differentiation.

Metformin impairs trophoblast metabolism and differentiation in dose dependent manner.

Metformin is a widely prescribed medication whose mechanism of action is not completely defined and whose role in gestational diabetes management remains controversial. In addition to increasing risks of fetal growth abnormalities and preeclampsia, gestational diabetes is associated with abnormalities in placental development including impairments in trophoblast differentiation. Given that metformin impacts cellular differentiation events in other systems, we assessed metformin's impact on trophoblast metabolism and differentiation. Using established cell culture models of trophoblast differentiation, oxygen consumption rates and relative metabolite abundance were determined following 200 µM (therapeutic range) and 2000 µM (supra-therapeutic range) metformin treatment using Seahorse and mass-spectrometry approaches. While no differences in oxygen consumption rates or relative metabolite abundance were detected between vehicle and 200 µM metformin treated cells, 2000 µM metformin impaired oxidative metabolism and increased abundance of lactate and TCA cycle intermediates, α-ketoglutarate, succinate, and malate. Examining differentiation, treatment with 2000 µM, but not 200 µM metformin, impaired HCG production and expression of multiple trophoblast differentiation markers. Overall, this work suggests that supra-therapeutic concentrations of metformin impairs trophoblast metabolism and differentiation whereas metformin concentrations in the therapeutic range do not strongly impact these processes.

Mitochondrial citrate metabolism and efflux regulates trophoblast differentiation.

Cytotrophoblasts fuse to form and renew syncytiotrophoblasts necessary to maintain placental health throughout gestation. During cytotrophoblast to syncytiotrophoblast differentiation, cells undergo regulated metabolic and transcriptional reprogramming. Mitochondria play a critical role in differentiation events in cellular systems, thus we hypothesized that mitochondrial metabolism played a central role in trophoblast differentiation. In this work, we employed static and stable isotope tracing untargeted metabolomics methods along with gene expression and histone acetylation studies in an established cell culture model of trophoblast differentiation. Trophoblast differentiation was associated with increased abundance of the TCA cycle intermediates citrate and α-ketoglutarate. Citrate was preferentially exported from mitochondria in the undifferentiated state but was retained to a larger extent within mitochondria upon differentiation. Correspondingly, differentiation was associated with decreased expression of the mitochondrial citrate transporter (CIC). CRISPR/Cas9 disruption of the mitochondrial citrate carrier showed that CIC is required for biochemical differentiation of trophoblasts. Loss of CIC resulted in broad alterations in gene expression and histone acetylation. These gene expression changes were partially rescued through acetate supplementation. Taken together, these results highlight a central role for mitochondrial citrate metabolism in orchestrating histone acetylation and gene expression during trophoblast differentiation.

Artifactual FA dimers mimic FAHFA signals in untargeted metabolomics pipelines.

FA esters of hydroxy FAs (FAHFAs) are lipokines with extensive structural and regional isomeric diversity that impact multiple physiological functions, including insulin sensitivity and glucose homeostasis. Because of their low molar abundance, FAHFAs are typically quantified using highly sensitive LC-MS/MS methods. Numerous relevant MS databases house in silico-spectra that allow identification and speciation of FAHFAs. These provisional chemical feature assignments provide a useful starting point but could lead to misidentification. To address this possibility, we analyzed human serum with a commonly applied high-resolution LC-MS untargeted metabolomics platform. We found that many chemical features are putatively assigned to the FAHFA lipid class based on exact mass and fragmentation patterns matching spectral databases. Careful validation using authentic standards revealed that many investigated signals provisionally assigned as FAHFAs are in fact FA dimers formed in the LC-MS pipeline. These isobaric FA dimers differ structurally only by the presence of an olefinic bond. Furthermore, stable isotope-labeled oleic acid spiked into human serum at subphysiological concentrations showed concentration-dependent formation of a diverse repertoire of FA dimers that analytically mimicked FAHFAs. Conversely, validated FAHFA species did not form spontaneously in the LC-MS pipeline. Together, these findings underscore that FAHFAs are endogenous lipid species.  However, nonbiological FA dimers forming in the setting of high concentrations of FFAs can be misidentified as FAHFAs. Based on these results, we assembled a FA dimer database to identify nonbiological FA dimers in untargeted metabolomics datasets.

Ketone body oxidation increases cardiac endothelial cell proliferation.

Blood vessel formation is dependent on metabolic adaption in endothelial cells. Glucose and fatty acids are essential substrates for ATP and biomass production; however, the metabolism of other substrates remains poorly understood. Ketone bodies are important nutrients for cardiomyocytes during starvation or consumption of carbohydrate-restrictive diets. This raises the question whether cardiac endothelial cells would not only transport ketone bodies but also consume some of these to achieve their metabolic needs. Here, we report that cardiac endothelial cells are able to oxidize ketone bodies and that this enhances cell proliferation, migration, and vessel sprouting. Mechanistically, this requires succinyl-CoA:3-oxoacid-CoA transferase, a key enzyme of ketone body oxidation. Targeted metabolite profiling revealed that carbon from ketone bodies got incorporated into tricarboxylic acid cycle intermediates as well as other metabolites fueling biomass production. Elevation of ketone body levels by a high-fat, low-carbohydrate ketogenic diet transiently increased endothelial cell proliferation in mouse hearts. Notably, in a mouse model of heart hypertrophy, ketogenic diet prevented blood vessel rarefication. This suggests a potential beneficial role of dietary intervention in heart diseases.

Acute aerobic exercise reveals that FAHFAs distinguish the metabolomes of overweight and normal-weight runners.

BackgroundResponses of the metabolome to acute aerobic exercise may predict maximum oxygen consumption (VO2max) and longer-term outcomes, including the development of diabetes and its complications.MethodsSerum samples were collected from overweight/obese trained (OWT) and normal-weight trained (NWT) runners prior to and immediately after a supervised 90-minute treadmill run at 60% VO2max (NWT = 14, OWT = 11) in a cross-sectional study. We applied a liquid chromatography high-resolution-mass spectrometry-based untargeted metabolomics platform to evaluate the effect of acute aerobic exercise on the serum metabolome.ResultsNWT and OWT metabolic profiles shared increased circulating acylcarnitines and free fatty acids (FFAs) with exercise, while intermediates of adenine metabolism, inosine, and hypoxanthine were strongly correlated with body fat percentage and VO2max. Untargeted metabolomics-guided follow-up quantitative lipidomic analysis revealed that baseline levels of fatty acid esters of hydroxy fatty acids (FAHFAs) were generally diminished in the OWT group. FAHFAs negatively correlated with visceral fat mass and HOMA-IR. Strikingly, a 4-fold decrease in FAHFAs was provoked by acute aerobic running in NWT participants, an effect that negatively correlated with circulating IL-6; these effects were not observed in the OWT group. Machine learning models based on a preexercise metabolite profile that included FAHFAs, FFAs, and adenine intermediates predicted VO2max.ConclusionThese findings in overweight human participants and healthy controls indicate that exercise-provoked changes in FAHFAs distinguish normal-weight from overweight participants and could predict VO2max. These results support the notion that FAHFAs could modulate the inflammatory response, fuel utilization, and insulin resistance.Trial registrationClinicalTrials.gov, NCT02150889.FundingNIH DK091538, AG069781, DK098203, TR000114, UL1TR002494.

Diminished ketone interconversion, hepatic TCA cycle flux, and glucose production in D-ß-hydroxybutyrate dehydrogenase hepatocyte-deficient mice.

OBJECTIVE: Throughout the last decade, interest has intensified in intermittent fasting, ketogenic diets, and exogenous ketone therapies as prospective health-promoting, therapeutic, and performance-enhancing agents. However, the regulatory roles of ketogenesis and ketone metabolism on liver homeostasis remain unclear. Therefore, we sought to develop a better understanding of the metabolic consequences of hepatic ketone body metabolism by focusing on the redox-dependent interconversion of acetoacetate (AcAc) and D-ß-hydroxybutyrate (D-ßOHB). METHODS: Using targeted and isotope tracing high-resolution liquid chromatography-mass spectrometry, dual stable isotope tracer nuclear magnetic resonance spectroscopy-based metabolic flux modeling, and complementary physiological approaches in novel cell type-specific knockout mice, we quantified the roles of hepatocyte D-ß-hydroxybutyrate dehydrogenase (BDH1), a mitochondrial enzyme required for NAD+/NADH-dependent oxidation/reduction of ketone bodies. RESULTS: Exogenously administered AcAc is reduced to D-ßOHB, which increases hepatic NAD+/NADH ratio and reflects hepatic BDH1 activity. Livers of hepatocyte-specific BDH1-deficient mice did not produce D-ßOHB, but owing to extrahepatic BDH1, these mice nonetheless remained capable of AcAc/D-ßOHB interconversion. Compared to littermate controls, hepatocyte-specific BDH1 deficient mice exhibited diminished liver tricarboxylic acid (TCA) cycle flux and impaired gluconeogenesis, but normal hepatic energy charge overall. Glycemic recovery after acute insulin challenge was impaired in knockout mice, but they were not more susceptible to starvation-induced hypoglycemia. CONCLUSIONS: Ketone bodies influence liver homeostasis. While liver BDH1 is not required for whole body equilibration of AcAc and D-ßOHB, loss of the ability to interconvert these ketone bodies in hepatocytes results in impaired TCA cycle flux and glucose production. Therefore, through oxidation/reduction of ketone bodies, BDH1 is a significant contributor to hepatic mitochondrial redox, liver physiology, and organism-wide ketone body homeostasis.

Determination of ketone bodies in biological samples via rapid UPLC-MS/MS.

Efforts to enhance wellness and ameliorate disease via nutritional, chronobiological, and pharmacological interventions have markedly intensified interest in ketone body metabolism. The two ketone body redox partners, acetoacetate (AcAc) and D-ß-hydroxybutyrate (D-ßOHB) serve distinct metabolic and signaling roles in biological systems. A highly efficient, specific, and reliable approach to simultaneously quantify AcAc and D-ßOHB in biological specimens is lacking, due to challenges of separating the structural isomers and enantiomers of ßOHB, and to the chemical instability of AcAc. Here we present a single UPLC-MS/MS method that simultaneously quantifies both AcAc and ßOHB using independent stable isotope internal standards for both ketones. This method incorporates one sample preparation step requiring only 7 min of analysis per sample. The output is linear over three orders of magnitude, shows very low limits of detection and quantification, is highly specific, and shows favorable recovery yields from mammalian serum and tissue samples. Tandem MS discriminates D-ßOHB from structural isomers 2- or 4-hydroxybutyrate as well as 3-hydroxyisobutyrate (3-HIB). Finally, a simple derivatization distinguishes D- and L-enantiomers of ßOHB, 3-HIB, and 2-OHB, using the same rapid chromatographic platform. Together, this simple, efficient, reproducible, scalable, and all-encompassing method will support basic and clinical research laboratories interrogating ketone metabolism and redox biochemistry.

Cytomegalovirus hepatitis and pancreatitis in the immunocompetent.

BACKGROUND: Cytomegalovirus (CMV) is a double-stranded DNA virus and a member of the Herpesviridae family. It is a lytic virus that causes a cytopathic effect in vitro and in vivo. CMV affects nearly all humans, with a 60%-100% seroprevalence worldwide, and in the immunocompetent it typically manifests as a mild and self-limiting mononucleosis syndrome. In immunocompromised patients, CMV has the ability to cause significant inflammation in many different organ systems. CASE REPORT: We report an unusual case of hepatitis and pancreatitis secondary to CMV in an immunocompetent patient. A 29-year-old male was admitted with elevated lipase, elevated aminotransferases, and epigastric pain after an acute viral prodrome. An initial CMV DNA polymerase chain reaction workup was positive, indicating acute or reactivated infection. Liver histology was consistent with CMV infection. Magnetic resonance cholangiopancreatography, endoscopic ultrasound, and intraoperative cholangiogram were not indicative of other etiologies. CMV viremia was successfully cleared with ganciclovir, and the patient experienced clinical and biochemical improvements. CONCLUSION: Pancreatitis and hepatitis secondary to CMV are rare but should be considered in the workup of immunocompetent patients, especially in the presence of a recent viral-like illness.

Should we Google it? Resource use by internal medicine residents for point-of-care clinical decision making.

PURPOSE: To determine which resources residents use at the point-of-care (POC) for decision making, the drivers for selection of these resources, and how residents use Google/Google Scholar to answer clinical questions at the POC. METHOD: In January 2012, 299 residents from three internal medicine residencies were sent an electronic survey regarding resources used for POC decision making. Resource use frequency and factors influencing choice were determined using descriptive statistics. Binary logistic regression analysis was performed to determine relationships between the independent variables. RESULTS: A total of 167 residents (56%) responded; similar numbers responded at each level of training. Residents most frequently reported using UpToDate and Google at the POC at least daily (85% and 63%, respectively), with speed and trust in the quality of information being the primary drivers of selection. Google, used by 68% of residents, was used primarily to locate Web sites and general information about diseases, whereas Google Scholar, used by 30% of residents, tended to be used for treatment and management decisions or locating a journal article. CONCLUSIONS: The findings suggest that internal medicine residents use UpToDate most frequently, followed by consultation with faculty and the search engines Google and Google Scholar; speed, trust, and portability are the biggest drivers for resource selection; and time and information overload appear to be the biggest barriers to resources such as Ovid MEDLINE. Residents frequently used Google and may benefit from further training in information management skills.

Feasibility and acceptability of a structured curriculum in teaching procedural and basic diagnostic ultrasound skills to internal medicine residents.

BACKGROUND: Point-of-care ultrasound has emerged as a powerful diagnostic tool and is also being increasingly used by clinicians to guide procedures. Many current and future internists desire training, yet no formal, multiple-application, program-wide teaching interventions have been described. INTERVENTION: We describe a structured 30-hour ultrasound training course in diagnostic and procedural ultrasound implemented during intern orientation. Internal medicine interns learned basic ultrasound physics and machine skills; focused cardiac, great vessel, pulmonary, and abdominal ultrasound diagnostic examinations; and procedural applications. RESULTS: In postcourse testing, learners demonstrated the ability to acquire images, had significantly increased knowledge scores (P < .001), and demonstrated good performance on practical scenarios designed to test abilities in image acquisition, interpretation, and incorporation into medical decision making. In the postcourse survey, learners strongly agreed (4.6 of 5.0) that ultrasound skills would be valuable during residency and in their careers. CONCLUSIONS: A structured ultrasound course can increase knowledge and can result in learners who have skills in image acquisition, interpretation, and integration in management. Future work will focus on refining and improving these skills to allow these learners to be entrusted with the use of ultrasound independently for patient care decisions.

Point-of-Care Ultrasound in Internal Medicine: A National Survey of Educational Leadership.

BACKGROUND: Ultrasound is a valuable tool in the safe performance of an increasing number of procedures. It has additionally emerged as a powerful instrument for point-of-care assessment by offering internists an opportunity to extend their traditional physical examination. OBJECTIVE: This study explored how internal medicine (IM) educators perceive the use of ultrasound for procedures and point-of-care assessments, the extent to which curricula for teaching IM residents ultrasound skills exist, and perceived barriers to teaching its use. METHODS: In February 2012, we administered a 27-question survey to all members of the Association of Program Directors in Internal Medicine, eliciting their opinions about the use of point-of-care ultrasound. RESULTS: Of 2200 surveys distributed electronically, 234 were returned (a 11% response rate), including 167 by program directors or assistant program directors. Respondents highly rated the usefulness of ultrasound for central-line placement, thoracentesis, paracentesis, and diagnosis of pleural effusions. Evaluation of vena cava and heart, and placement of radial artery catheters received somewhat lower usefulness scores. Forty-five respondents (25%) reported having formal curricula to teach point-of-care ultrasound, and 46 respondents without current ultrasound programs were planning to initiate them in the next 12 months. Potential barriers to teaching and use of ultrasound included the time and cost to train faculty, the cost of ultrasound machines, and the time required to train residents. CONCLUSIONS: Educational leaders in IM view point-of-care ultrasound as a valuable tool in diagnosis and procedures, and many residency programs are teaching these skills to their learners.

Haematological, neurological and electrocardiographic findings in secondary hypothermia.

The association between secondary hypothermia and pancytopaenia is uncommon. A young woman presented with chronic hypothermia (28.8-34.6°C) secondary to surgical hypothalamic injury postcraniopharyingioma resection as a child. Associated findings included pancytopaenia (haemoglobin 8.1 g/dl, leucocytes 3500/mm(3), platelets 63,000/mm(3)), ataxia, upper motor neuron signs, decreased level of consciousness and new ECG changes. An extensive evaluation failed to reveal any cause of pancytopaenia other than chronic hypothermia. The haematological and neurological changes improved after active rewarming.