Defect In Uptake Research Articles

Factors Influencing Success in Endoscopic Treatment of Grade 4-5 Primary Vesicoureteric Reflux (VUR) in Infancy and Childhood.

There is equipoise among pediatric urologists regarding endoscopic versus surgical intervention for symptomatic Grade 4-5 Vesicoureteric Reflux (VUR), particularly in infancy. Our aim was to assess outcomes of first-line endoscopic treatment in all cases of symptomatic Grade 4-5 VUR and we hypothesised that using endoscopic Dx/HA as first line management for primary VUR would obviate the need for ureteric reimplantation in the majority of cases. Retrospective single-surgeon analysis of consecutive patients with primary Grade 4-5 VUR over 15 years. Indication for intervention was breakthrough UTI on prophylaxis. Endoscopic dextranomer/hyaluronic acid co-polymer (Dx/HA; Deflux®) injection was first-line procedure. Primary outcomes were both post-procedure febrile culture positive urinary tract infection (UTI) and VUR recurrence on post-operative VCUG requiring further surgical intervention. We postulated that risk factors influencing outcome are: age under 1 year, female gender, postnatal versus antenatal presentation, duplex anatomy, circumcision status and presence of congenital uptake defects on DMSA. Data analysed using Fisher's Exact Test/Multivariate Analysis. 77 patients with Grade 4-5 VUR were identified, of whom 49 (11 bilateral) underwent a Dx/HA injection at median 12 (3-84) months. Median follow-up post-injection was 32 (2-145) months. There were no reported complications or ureteral obstruction. Sixteen (33%) patients suffered a febrile UTI at follow-up; on further investigation, half (8/16) of these were found to have recurrent VUR. Therefore 67% were symptom free and 84% did not require further intervention after one injection (41/49), and 98% after further injections (48/49). Duplex systems had a similar outcome of 80% not requiring further intervention. On multivariate analysis, males were found to have a significantly better outcome than females (p<0.015) irrespective of circumcision status. Forty-one percent of the children in our cohort had uptake defects on DMSA prior to intervention, but this did not have any difference on outcome. Endoscopic Dx/HA injection is a safe first-line, day-case treatment for Grade 4-5 VUR in children of any age, with a low complication rate. Two-thirds of patients are asymptomatic after one injection; 84% do not require further procedures after one injection, and 98% after 2 injections.

7449 A Genome-wide CRISPR Screen Identifies Drivers of Impaired Glucose Uptake in Human Insulin Resistance

Abstract Disclosure: N. Haider: None. Y. Lee: None. P. Yi: None. C.R. Kahn: None. Insulin resistance is a major risk factor in the development of type 2 diabetes (T2D), and metabolic syndrome. Although 25% of people within the general non-diabetic population are insulin resistant, the primary underlying cause of insulin resistance remains elusive. In this study, we have used induced pluripotent stem cells (iPSC) derived from non-diabetic humans at both ends of the insulin sensitivity spectrum, i.e., the top 20% of insulin resistance vs. the top 20% of insulin sensitive, as well as individuals with T2D to model human insulin resistance. We find that iPSCs differentiated into myoblasts (iMyos) from T2D and non-diabetic individuals in the highest quintile of insulin resistance (I-Res) show impaired insulin signaling and defective insulin-stimulated glucose uptake, as compared to iMyos from the insulin sensitive individuals (I-Sen), indicating that these cells in vitro mirror the alterations seen in vivo in a cell autonomous manner. To uncover the primary upstream drivers that contribute to the impaired glucose uptake associated with insulin resistance, we conducted a genome-wide loss-of-function screen using a CRISPR-based approach to identify genes that positively or negatively regulated glucose uptake in I-Res and T2D iMyos. Knockdown of ∼525 genes show effect to rescue the impaired glucose uptake in both I-Res and T2D iMyos, i.e., were negative regulators of glucose uptake. We hypothesized that important negative regulators of glucose uptake might be over-expressed at the protein level in I-Res and T2D iMyos and crossing the iMyos proteomics data with the CRISPR screen revealed 8 top candidates that are increased at the protein level and whose knockdown rescued glucose uptake in I-Res and T2D iMyos. These included candidates associated with cytoskeleton changes, protein kinases, transmembrane transport, mitochondrial and nuclear proteins. In summary, iPSC derived myoblasts from patients with insulin resistance and T2D mirror defects in glucose uptake observed in vivo. Combining CRISPR screening and global proteomics, we have identified important upstream regulators of insulin resistance in humans. Presentation: 6/2/2024

330 Growth performance, incidence of scours, and plasma metabolites in beef × dairy crossbred calves transported at 2, 4, 8 and 14 d of age

Abstract Transportation can compromise health and production performance in young calves. Although widely accepted that the younger calves are, the greater the probability of negative outcomes, there still is a lack of evidence-based recommendations on the minimum age at transportation. Our objective was to evaluate the impact of transport age on growth performance, incidence of scours, and plasma metabolites over the first 28 d post-transport in Charolais × Holstein crossbred calves. Calves (n = 36) ages 2, 4, 8 and 14-d old were transported in summer from a commercial farm to an on-campus calf rearing facility (410 miles). Calf body weight (BW) was recorded before departure, on arrival and d 28 post-transport. Dry matter intake (DMI) and fecal scores were recorded daily. Blood samples collected prior to transportation, on arrival, and d 7 and 28 post-transport were used for targeted metabolomics analysis (Biocrates MxP Quant 500 kit). Growth performance and fecal score data were analyzed using PROC MIXED (SAS) whereas R was used for predictive modeling of metabolomics data. Over the 28-d period post-transport, DMI was greater (P &amp;lt; 0.01) for 14 d than 2 and 4 d old calves; however, it did not differ between 2, 4, and 8 d old calves. Average daily gain (ADG) and feed efficiency (FE) were also greater (P &amp;lt; 0.01) for 14 d than 2, 4, and 8 d old calves. During wk 1 post-transport, the total number of days calves had scours was least (P &amp;lt; 0.01) for 2 and 14 d, intermediate for 4 d, and greatest for 8 d old calves. During wk 2, the total number of days with scours was less (P &amp;lt; 0.01) for 8 and 14 d (average of 2 d) compared with 2 and 4 d old calves (5 d). Additionally, the total number of days calves had scours during the first 2 wk post-transport tended (P = 0.08) to be greater for 2, 4, and 8 d than 14 d old calves. However, during wk 3 and 4 post-transport, there were no differences (P ≥ 0.58) in the total number of days with scours across transport age. Arginine methylation, d 7 of measurements, carnitine uptake defect, phosphatidic acid 16:0:18:2, methylenetetrahydrofolate reductase, sodium, triglyceride 18:2:34:4, threonine, α-aminobutyric acid, and glycolithocholic acid 3-sulfate were the most important features in terms of predicting the occurrence of scours. Overall, DMI, ADG and FE were less for calves transported at 2, 4, and 8 d than at 14 d of age, which could partially be attributed to differences in the incidence rate of scours. In addition, several plasma metabolites could be good predictors of scours in transported calves.

Intra-operative Measurement of Eustachian Tube Orifice, and Its Correlation With Post-operative Surgical Outcome in Chronic Suppurative Otitis Media Patients.

Background Chronic suppurative otitis media (CSOM) is the inflammation of the middle ear mucosa for more than two weeks, resulting in ear discharge. It is associated with hearing loss and the presence of a perforation in the tympanic membrane. Tympanoplasty is performed to place a graft and clear the disease in the middle ear. Despite adequate disease clearance and proper graft placement, graft failure and disease persistence occur due to Eustachian tube (ET) dysfunction. The ET plays a significant role in the ventilation of the middle ear. Hence, this study was conducted to determine the significance of ET size for post-operative graft uptake. Methodology A total of 55 patients with inactive CSOM were included in the study. Their demographic data were recorded. Patients previously operated on for CSOM, cases with traumatic perforation of the tympanic membrane, congenital anomalies (e.g., cleft lip/cleft palate), and atticoantral disease were excluded. Thorough history taking and examination, including otoscopy and examination of the nose, throat, and oropharynx, were conducted. Once the patient was deemed fit for surgery, they underwent tympanoplasty. Intraoperatively, the ET size was measured using the tip of the suction cannulas. They were followed up after three months to assess graft uptake. Results Out of 55 patients included in the study, 42 (76%) had good graft uptake, while 13 (24%) had defects in graft uptake. Graft uptake failed in patients with an ET diameter of <3 mm. Post-operative graft uptake was observed in the majority of patients with a wider ET diameter, ranging between 3 mm and 6 mm, with a statistically significant p-value of 0.00 (0.05), as determined by Pearson's Chi-square test. Conclusion In our study, we found that there is an association between the ET diameter and post-operative graft uptake. Hence, a wider ET may improve middle ear ventilation and play an important role in post-operative graft uptake.

Phosphate availability conditions caspofungin tolerance, capsule attachment and titan cell formation in Cryptococcus neoformans.

There is an urgent need for new antifungal drugs to treat invasive fungal diseases. Unfortunately, the echinocandin drugs that are fungicidal against other important fungal pathogens are ineffective against Cryptococcus neoformans, the causative agent of life-threatening meningoencephalitis in immunocompromised people. Contributing mechanisms for echinocandin tolerance are emerging with connections to calcineurin signaling, the cell wall, and membrane composition. In this context, we discovered that a defect in phosphate uptake impairs the tolerance of C. neoformans to the echinocandin caspofungin. Our previous analysis of mutants lacking three high affinity phosphate transporters revealed reduced elaboration of the polysaccharide capsule and attenuated virulence in mice. We investigated the underlying mechanisms and found that loss of the transporters and altered phosphate availability influences the cell wall and membrane composition. These changes contribute to the shedding of capsule polysaccharide thus explaining the reduced size of capsules on mutants lacking the phosphate transporters. We also found an influence of the calcineurin pathway including calcium sensitivity and an involvement of the endoplasmic reticulum in the response to phosphate limitation. Furthermore, we identified membrane and lipid composition changes consistent with the role of phosphate in phospholipid biosynthesis and with previous studies implicating membrane integrity in caspofungin tolerance. Finally, we discovered a contribution of phosphate to titan cell formation, a cell type that displays modified cell wall and capsule composition. Overall, our analysis reinforces the importance of phosphate as a regulator of cell wall and membrane composition with implications for capsule attachment and antifungal drug susceptibility.

Gd-EOB-DTPA enhanced MRI nomogram model to differentiate hepatocellular carcinoma and focal nodular hyperplasia both showing iso- or hyperintensity in the hepatobiliary phase

BackgroundTo develop and validate a nomogram model based on Gd-EOB-DTPA enhanced MRI for differentiation between hepatocellular carcinoma (HCC) and focal nodular hyperplasia (FNH) showing iso- or hyperintensity in the hepatobiliary phase (HBP).MethodsA total of 75 patients with 49 HCCs and 26 FNHs randomly divided into a training cohort (n = 52: 34 HCC; 18 FNH) and an internal validation cohort (n = 23: 15 HCC; 8 FNH). A total of 37 patients (n = 37: 25 HCC; 12 FNH) acted as an external test cohort. The clinical and imaging characteristics between HCC and FNH groups in the training cohort were compared. The statistically significant parameters were included into the FAE software, and a multivariate logistic regression classifier was used to identify independent predictors and establish a nomogram model. Receiver operating characteristic (ROC) curves were used to evaluate the prediction ability of the model, while the calibration and decision curves were used for model validation. Subanalysis was used to compare qualitative and quantitative characteristics of patients with chronic hepatitis and cirrhosis between the HCC and FNH groups.ResultsIn the training cohort, gender, age, enhancement rate in the arterial phase (AP), focal defects in uptake were significant predictors for HCC showing iso- or hyperintensity in the HBP. In the training cohort, area under the curve (AUC), sensitivity and specificity of the nomogram model were 0.989(95%CI: 0.967-1.000), 97.1% and 94.4%. In the internal validation cohort, the above three indicators were 0.917(95%CI: 0.782-1.000), 93.3% and 87.5%. In the external test cohort, the above three indicators were 0.960(95%CI: 0.905-1.000), 84.0% and 100.0%. The results of subanalysis showed that age was the independent predictor in the patients with chronic hepatitis and cirrhosis between HCC and FNH groups.ConclusionsGd-EOB-DTPA enhanced MRI nomogram model may be useful for discriminating HCC and FNH showing iso- or hyperintensity in the HBP before surgery.

Risk Stratification in Cardiac Sarcoidosis With Cardiac Positron Emission Tomography: A Systematic Review and Meta-Analysis

Although positron emission tomography (PET) imaging is well established for its diagnostic role in cardiac sarcoidosis, less is known about the prognostic value of PET and its use in risk stratification for major adverse cardiac events (MACE). The goal of this study was to perform a systematic review and meta-analysis looking at the prognostic value of PET imaging in patients with cardiac sarcoidosis. Study investigators systematically searched EMBASE (Excerpta Medica dataBASE), MEDLINE, PubMed, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, CINAHL (Cumulative Index to Nursing and Allied Health Literature), ClinicalTrials.gov, and the European Union Clinical Trial Registry for cardiac sarcoidosis and PET imaging. The primary outcome of interest was MACE. The search revealed 3,010 records, of which 55 studies were included. This represented 5,250 patients. Factors associated with MACE included the following: the combination of abnormal fluorodeoxyglucose (FDG) uptake and perfusion defect, which had an OR of 2.86 (95%CI: 1.74-4.71; P< 0.0001); abnormal perfusion or FDG uptake, which had an OR of 2.69 (95%CI: 1.67-4.33); abnormal FDG uptake, which had an OR of 2.61 (95%CI: 1.51-4.50); focal abnormal right ventricular uptake, which had an OR of 6.27 (95%CI: 3.19-12.32; P< 0.00001); and a lack of response to immunosuppression on serial PET, which had an OR of 8.43 (95%CI: 3.25-21.85; P< 0.0001). A QUIPS (Quality in Prognostic Studies) tool analysis found a low to moderate risk of bias, particularly given the small sample sizes in the individual studies. Multiple cardiac PET parameters provide risk stratification value in cardiac sarcoidosis. Focal right ventricular uptake and a lack of response to immunosuppressive therapy on serial PET imaging were particularly predictive of MACE.

Depression-related testosterone deficiency is linked to reduced cholesterol levels in Leydig cells of CUMS mice.

Male reproductive problems under psychological stress were widely studied. Using chronically unpredictable mild stress-treated mice, we found that reduced serum testosterone levels were related to the low level of cholesterol in the Leydig cells. Testosterone deficiency in humans can be caused by depressive symptoms; however, the causes of this deficiency are incompletely understood. This study demonstrates that male mice with depression-like symptoms due to chronic unpredictable mild stress (CUMS) show reduced serum testosterone levels and disrupted sexual behaviors. However, the observed testosterone reductions were not caused by apoptosis of Leydig cells. Oil red O staining revealed that lipid droplets were dramatically decreased in Leydig cells, suggesting that defects in cholesterol uptake might be related to testosterone deficiency in depression-like mice. To investigate the potential mechanism, lipid homeostasis was examined by liquid chromatography-tandem mass spectrometry. The results revealed that higher levels of sphingomyelins (SM 8:0;2O/28:1, 18:0;2O/22:2, 33:0;3O, 33:1;2O) were linked to decreased cholesterol levels. Further investigation indicated that testosterone biosynthesis from cholesterol in Leydig cells was impaired by the downregulation of Ldlr, Srb1, Lhr, and P450scc. Elevated levels of interferon signaling-associated pathways in depression-like mice testes may also contribute to decreased testosterone levels. Taken together, these findings provide a novel understanding of male reproductive problems under psychological stress and suggest that cholesterol uptake might be a causal factor in reduced testosterone production in depression-like mice.

Expanded Newborn Screening for Inborn Errors of Metabolism in Hong Kong: Results and Outcome of a 7 Year Journey.

Newborn screening (NBS) is an important public health program that aims to identify pre-symptomatic healthy babies that will develop significant disease if left undiagnosed and untreated. The number of conditions being screened globally is expanding rapidly in parallel with advances in technology, diagnosis, and treatment availability for these conditions. In Hong Kong, NBS for inborn errors of metabolism (NBSIEM) began as a pilot program in October 2015 and was implemented to all birthing hospitals within the public healthcare system in phases, with completion in October 2020. The number of conditions screened for increased from 21 to 24 in April 2016 and then to 26 in October 2019. The overall recruitment rate of the NBS program was 99.5%. In the period between October 2015 and December 2022, 125,688 newborns were screened and 295 were referred back for abnormal results. The recall rate was reduced from 0.26% to 0.12% after the implementation of second-tier testing. An inherited metabolic disorder (IMD) was eventually confirmed in 47 infants, making the prevalence of IMD in Hong Kong 1 in 2674. At the time of the NBS result, 78.7% of the newborns with IMD were asymptomatic. There were two deaths reported: one newborn with methylmalonic acidemia cobalamin B type (MMACblB) died after the initial crisis and another case of carnitine palmitoyltransferase II deficiency (CPTII) died at 18 months of age after metabolic decompensation. The most common IMD noted were disorders of fatty acid oxidation metabolism (40%, 19 cases), closely followed by disorders of amino acid metabolism (38%, 18 cases), with carnitine uptake defect (19.1%, 9 cases) and citrullinemia type II (17%, 8 cases) being the two most common IMD picked up by the NBSIEM in Hong Kong. Out of the all the IMDs identified, 19.1% belonged to diverse ethnic groups. False negative cases were reported for citrullinemia type II and congenital adrenal hyperplasia during this period.

Isolation, heterologous expression, and functional determination of an iron regulated transporter (IRT) gene involved in Fe2+ transport and tolerance to Fe2+ deficiency in Vitis vinifera

In plants, iron (Fe) regulated transporters (IRT) play important roles in uptake and transport of Fe that contributes to plant growth and development. However, biological functions of IRT transporters in fruit trees are still unknown. This study isolated 10 VvIRT genes from ‘Marselan’ grape, with varying expression levels across different tissues/organs, particularly enhanced under Fe depletion, especially in roots. Notably, VvIRT7 is the most abundantly expressed IRT gene in grape, beneficially restoring the Fe2+ uptake defect of yeast mutant DEY1453. Furthermore, VvIRT7 showed dominant expression in the roots of irt1/35S::IRT7 complementation lines. Overexpressing of VvIRT7 rescued the retarded growth of irt1 knockout mutant, by increasing the fresh weight, dry weight, total root length, total root surface, lateral root numbers, total leaf chlorophyll, ACO activity, NiR activity, SDH activity, and tissue Fe concentration. This study provides insights for understanding molecular mechanisms of Fe uptake and transport in grape.

Klebsiella pneumoniae DedA family proteins have redundant roles in divalent cation homeostasis and resistance to phagocytosis.

The DedA superfamily is a highly conserved family of membrane proteins. Deletion of Escherichia coli yqjA and yghB, encoding related DedA family proteins, results in sensitivity to elevated temperature, antibiotics, and alkaline pH. The human pathogen Klebsiella pneumoniae possesses genes encoding DedA family proteins with >90% amino acid identity to E. coli YqjA and YghB. We hypothesized that the deletion of K. pneumoniae yqjA and yghB will impact its physiology and may reduce its virulence. The K. pneumoniae ΔyqjA ΔyghB mutant (strain VT101) displayed a growth defect at 42°C and alkaline pH sensitivity, not unlike its E. coli counterpart. However, VT101 retained mostly wild-type resistance to antibiotics. We found VT101 was sensitive to the chelating agent EDTA, the anionic detergent SDS, and agents capable of alkalizing the bacterial cytoplasm such as bicarbonate or chloroquine. We could restore growth at alkaline pH and at elevated temperature by addition of 0.5-2 mM Ca2+ or Mg2+ to the culture media. VT101 displayed a slower uptake of calcium, which was dependent upon calcium channel activity. VT201, with similar deletions as VT101 but derived from a virulent K. pneumoniae strain, was highly susceptible to phagocytosis by alveolar macrophages and displayed a defect in the production of capsule. These findings suggest divalent cation homeostasis and virulence are interlinked by common functions of the DedA family.IMPORTANCEKlebsiella pneumoniae is a dangerous human pathogen. The DedA protein family is found in all bacteria and is a membrane transporter often required for virulence and antibiotic resistance. K. pneumoniae possesses homologs of E. coli YqjA and YghB, with 60% amino acid identity and redundant functions, which we have previously shown to be required for tolerance to biocides and alkaline pH. A K. pneumoniae strain lacking yqjA and yghB was found to be sensitive to alkaline pH, elevated temperature, and EDTA/SDS and displayed a defect in calcium uptake. Sensitivity to these conditions was reversed by addition of calcium or magnesium to the growth medium. Introduction of ΔyqjA and ΔyghB mutations into virulent K. pneumoniae resulted in the loss of capsule, increased phagocytosis by macrophages, and a partial loss of virulence. These results show that targeting the Klebsiella DedA family results in impaired divalent cation transport and, in turn, loss of virulence.

18F]PSMA-1007 PET is comparable to [99mTc]Tc-DMSA SPECT for renal cortical imaging

BackgroundScintigraphy using technetium-99m labelled dimercaptosuccinic acid ([99mTc]Tc-DMSA), taken up in the proximal tubules, is the standard in functional imaging of the renal cortex. Recent guidelines recommend performing [99mTc]Tc-DMSA scintigraphy with single photon emission computed tomography (SPECT). Prostate-specific membrane antigen (PSMA) targeted positron emission tomography (PET) is used for staging and localization of recurrence in prostate cancer. A high renal uptake is often seen on PSMA PET, concordant with known PSMA expression in proximal tubules. This suggests PSMA PET could be used analogous to [99mTc]Tc-DMSA scintigraphy for renal cortical imaging. [18F]PSMA-1007 is a promising radiopharmaceutical for this purpose due to low urinary clearance. In this study, we aimed to compare [18F]PSMA-1007 PET to [99mTc]Tc-DMSA SPECT regarding split renal uptake and presence of renal uptake defects, in patients with prostate cancer. Three readers interpreted PET and SPECT images regarding presence of renal uptake defects, with each kidney split into cranial, mid and caudal segments. Kidneys were segmented in PET and SPECT images, and left renal uptake as a percentage of total renal uptake was measured.ResultsTwenty patients with prostate cancer were included. 2 participants had single kidneys; thus 38 kidneys were evaluated. A total of 29 defects were found on both [99mTc]Tc-DMSA SPECT and [18F]PSMA-1007 PET. Cohen’s kappa for concordance regarding presence of any defect was 0.76 on a per-segment basis and 0.67 on a per-kidney basis. Spearman’s r for left renal uptake percentage between [99mTc]Tc-DMSA SPECT and [18F]PSMA-1007 PET was 0.95.Conclusions[18F]PSMA-1007 PET is comparable to [99mTc]Tc-DMSA SPECT for detection of uptake defects in this setting. Measurements of split renal function made using [18F]PSMA-1007 PET are valid and strongly correlated to measurements made with [99mTc]Tc-DMSA SPECT.

The dysfunctional immune response in renal cell carcinoma correlates with changes in the metabolic landscape of ccRCC during disease progression

Renal cell carcinoma is an immunogenic tumour with a prominent dysfunctional immune cell infiltrate, unable to control tumour growth. Although tyrosine kinase inhibitors and immunotherapy have improved the outlook for some patients, many individuals are non-responders or relapse despite treatment. The hostile metabolic environment in RCC affects the ability of T-cells to maintain their own metabolic programme constraining T-cell immunity in RCC. We investigated the phenotype, function and metabolic capability of RCC TILs correlating this with clinicopathological features of the tumour and metabolic environment at the different disease stages. Flow cytometric analysis of freshly isolated TILs showed the emergence of exhausted T-cells in advanced disease based on their PD-1high and CD39 expression and reduced production of inflammatory cytokines upon in vitro stimulation. Exhausted T-cells from advanced stage disease also displayed an overall phenotype of metabolic insufficiency, characterized by mitochondrial alterations and defects in glucose uptake. Nanostring nCounter cancer metabolism assay on RNA obtained from 30 ccRCC cases revealed significant over-expression of metabolic genes even at early stage disease (pT1-2), while at pT3-4 and the locally advanced thrombi stages, there was an overall decrease in differentially expressed metabolic genes. Notably, the gene PPARGC1A was the most significantly down-regulated gene from pT1-2 to pT3-4 RCC which correlated with loss of mitochondrial function in tumour-infiltrating T-cells evident at this tumour stage. Down-regulation of PPARGC1A into stage pT3-4 may be the ‘tipping-point’ in RCC disease progression, modulating immune activity in ccRCC and potentially reducing the efficacy of immunotherapies in RCC and poorer patient outcomes.

Activation of the integrated stress response rewires cardiac metabolism in Barth syndrome

Barth Syndrome (BTHS) is an inherited cardiomyopathy caused by defects in the mitochondrial transacylase TAFAZZIN (Taz), required for the synthesis of the phospholipid cardiolipin. BTHS is characterized by heart failure, increased propensity for arrhythmias and a blunted inotropic reserve. Defects in Ca2+-induced Krebs cycle activation contribute to these functional defects, but despite oxidation of pyridine nucleotides, no oxidative stress developed in the heart. Here, we investigated how retrograde signaling pathways orchestrate metabolic rewiring to compensate for mitochondrial defects. In mice with an inducible knockdown (KD) of TAFAZZIN, and in induced pluripotent stem cell-derived cardiac myocytes, mitochondrial uptake and oxidation of fatty acids was strongly decreased, while glucose uptake was increased. Unbiased transcriptomic analyses revealed that the activation of the eIF2α/ATF4 axis of the integrated stress response upregulates one-carbon metabolism, which diverts glycolytic intermediates towards the biosynthesis of serine and fuels the biosynthesis of glutathione. In addition, strong upregulation of the glutamate/cystine antiporter xCT increases cardiac cystine import required for glutathione synthesis. Increased glutamate uptake facilitates anaplerotic replenishment of the Krebs cycle, sustaining energy production and antioxidative pathways. These data indicate that ATF4-driven rewiring of metabolism compensates for defects in mitochondrial uptake of fatty acids to sustain energy production and antioxidation.

The Escherichia coli MFS-type transporter genes yhjE, ydiM, and yfcJ are required to produce an active bo3 quinol oxidase.

Heme-copper oxygen reductases are membrane-bound oligomeric complexes that are integral to prokaryotic and eukaryotic aerobic respiratory chains. Biogenesis of these enzymes is complex and requires coordinated assembly of the subunits and their cofactors. Some of the components are involved in the acquisition and integration of different heme and copper (Cu) cofactors into these terminal oxygen reductases. As such, MFS-type transporters of the CalT family (e.g., CcoA) are required for Cu import and heme-CuB center biogenesis of the cbb3-type cytochrome c oxidases (cbb3-Cox). However, functionally homologous Cu transporters for similar heme-Cu containing bo3-type quinol oxidases (bo3-Qox) are unknown. Despite the occurrence of multiple MFS-type transporters, orthologs of CcoA are absent in bacteria like Escherichia coli that contain bo3-Qox. In this work, we identified a subset of uncharacterized MFS transporters, based on the presence of putative metal-binding residues, as likely candidates for the missing Cu transporter. Using a genetic approach, we tested whether these transporters are involved in the biogenesis of E. coli bo3-Qox. When respiratory growth is dependent on bo3-Qox, because of deletion of the bd-type Qox enzymes, three candidate genes, yhjE, ydiM, and yfcJ, were found to be critical for E. coli growth. Radioactive metal uptake assays showed that ΔydiM has a slower 64Cu uptake, whereas ΔyhjE accumulates reduced 55Fe in the cell, while no similar uptake defect is associated with ΔycfJ. Phylogenomic analyses suggest plausible roles for the YhjE, YdiM, and YfcJ transporters, and overall findings illustrate the diverse roles that the MFS-type transporters play in cellular metal homeostasis and production of active heme-Cu oxygen reductases.

Neurohumoral Markers of Cardiac Autonomic Denervation after Surgical Ablation of Long-Standing Persistent Atrial Fibrillation.

Although the autonomic nervous system has an evident impact on cardiac electrophysiology and radiofrequency ablation (RFA) is the conventional technique for treating persistent atrial fibrillation, the specific effects of RFA have been insufficiently studied to date. Here, we investigated whether RFA affects neurohumoral transmitter levels and myocardial 123I-metaiodobenzylguanidine (123I-MIBG) uptake. To perform this task, we compared two groups of patients with acquired valvular heart disease: patients who had undergone surgical AF ablation and patients with sinus rhythm. The decrease in norepinephrine (NE) level in the coronary sinus had a direct association with the heart-to-mediastinum ratio (p = 0.02) and a negative correlation with 123I-MIBG uptake defects (p = 0.01). The NE level decreased significantly after the main surgery, both in patients with AF (p = 0.0098) and sinus rhythm (p = 0.0039). Furthermore, the intraoperative difference between the norepinephrine levels in the ascending aorta and coronary sinus (ΔNE) of -400 pg/mL was determined as a cut-off value to evaluate RFA efficacy, as denervation failed in all patients with ΔNE < -400 pg/mL. Hence, ΔNE can be utilized to predict the efficacy of the "MAZE-IV" procedure and to assess the risk of AF recurrence after RFA.

Bile acid dysmetabolism in inflammatory bowel diseases

Aim: To summarize the state-of-the-art data on the molecular mechanisms of bile acid (BA) synthesis and absorption, their impaired absorption and receptor-dependent signaling, as well as on the effects of the gut microbiota on BA metabolism in inflammatory bowel diseases (IBD).&#x0D; Key messages: BA malabsorption is one of the relevant mechanisms in the development of diarrhea in IBD. It may occur due to various disorders of the ileum, such as terminal ileitis, ileocolitis or ileocecal resection in Crohn's disease and ileoanal reservoir in ulcerative colitis. Molecular mechanisms of BA malabsorption in IBD are related to a defect in the BA uptake by the apical sodium dependent bile acid transporter (ASBT), as well as to a decrease in the expression of pregnane X receptor (PXR) and farnesoid X receptor (FXR), whose activation by glucocorticoids results in an increase in the BA reabsorption in the ileum and a decrease in hologenic diarrhea. The metabolic profile of luminal BA in IBD is characterized by an increased content of conjugated and 3-OH-sulfated BA and reduced levels of secondary BA. The decrease in the relative abundance of the Lachnospiraceae and Oscillospiraceae spp. in IBD patients leads to a decrease in the efficiency of microbial biotransformation of BA. Changes in the BA metabolic profile in IBD affect the gut microbiota, and impaired interaction with the FXR, PXR, G protein-coupled bile acid receptor (GPBAR1), retinoid-related orphan receptors (RORs) and vitamin D receptor (VDR) results in a pro-inflammatory response and increased intestinal permeability, bacterial translocation, and IBD progression. BA metabolism in IBD-associated primary sclerosing cholangitis (PSC-IBD) is characterized by a significant decrease in the luminal BA pool, and the microbiota composition is remarkable for an increase in the relative abundance of Fusobacterium and Ruminococcus spp., and a decrease in Veillonella, Dorea, Blautia, Lachnospira and Roseburia.&#x0D; Conclusion: Disordered synergistic interplay of BA with intestinal microbiota results in disruption of the ligand-receptor interaction and BA metabolic transformation, which contributes to the activation of the immune system, formation of a vicious circle of chronic inflammation and IBD progression. Further studies into mutual influence of the gut microbiota, BA metabolism and receptor signaling may promote the development of new methods for the diagnosis and treatment of IBD.

Mild carnitine uptake defect due to a novel homozygous mutation in the SLC22A5 gene detected by newborn screening

Mild carnitine uptake defect due to a novel homozygous mutation in the SLC22A5 gene detected by newborn screening

Role of antidiabetic agents in type 2 diabetes patients with chronic kidney disease.

Insulin resistance is a condition in which the target tissues have a decreased response to insulin signaling, resulting in glucose uptake defect, and an increased blood sugar level. Pancreatic beta cells thus enhance insulin production to compensate. This situation may cause further beta cell dysfunction and failure, which can lead diabetes mellitus (DM). Insulin resistance is thus an important cause of the development of type 2 DM. Insulin resistance has also been found to have a strong relationship with cardiovascular disease and is common in chronic kidney disease (CKD) patients. The mechanisms of insulin resistance in CKD are complex and multifactorial. They include physical inactivity, inflammation and oxidative stress, metabolic acidosis, vitamin D deficiency, adipose tissue dysfunction, uremic toxins, and renin-angiotensin-aldosterone system activation. Currently, available anti-diabetic agents, such as biguanides, sulfonylureas, thiazolidinediones, alfa-glucosidase inhibitors, glucagon-like peptide-1-based agents, and sodium-glucose co-transporter-2 inhibitors, have different effects on insulin resistance. In this short review, we describe the potential mechanisms of insulin resistance in CKD patients. We also review the interaction of currently available anti-diabetic medications with insulin resistance.

Maf family transcription factors are required for nutrient uptake in the mouse neonatal gut.

There are fundamental differences in how neonatal and adult intestines absorb nutrients. In adults, macromolecules are broken down into simpler molecular components in the lumen of the small intestine, then absorbed. In contrast, neonates are thought to rely on internalization of whole macromolecules and subsequent degradation in the lysosome. Here, we identify the Maf family transcription factors MAFB and c-MAF as markers of terminally differentiated intestinal enterocytes throughout life. The expression of these factors is regulated by HNF4α and HNF4γ, master regulators of enterocyte cell fate. Loss of Maf factors results in a neonatal-specific failure to thrive and loss of macromolecular nutrient uptake. RNA-Seq and CUT&RUN analyses defined an endo-lysosomal program as being downstream of these transcription factors. We demonstrate major transcriptional changes in metabolic pathways, including fatty acid oxidation and increases in peroxisome number, in response to loss of Maf proteins. Finally, we show that loss of BLIMP1, a repressor of adult enterocyte genes, shows highly overlapping changes in gene expression and similar defects in macromolecular uptake. This work defines transcriptional regulators that are necessary for nutrient uptake in neonatal enterocytes.