The development of intestinal failure-related complications in Finnish adults is unknown. This study aimed to investigate the incidence of catheter-related bloodstream infections (CRBSI), and the ...longitudinal changes in biochemical liver and kidney tests in a nationwide cohort.
The search for Finnish adults with intestinal failure (IF) utilized a survey to Finnish health-care providers (n = 111) with the potential to provide long-term parenteral support (PS) for adult IF. Our nationwide, cross-sectional cohort included all IF patients aged ≥ 18 years who had received PS for ≥ 120 d in 2017. Data regarding CRBSI and biochemical liver and kidney tests were collected from patient records at the start of PS up to the latest available measurement in 2017.
In the nationwide cohort of 52 patients, the CRBSI incidence was 1.35/1000 catheter days. Seventy-three percent of CRBSI in a long-term catheter led to catheter replacement. During a median PS duration of 27.5 (interquartile range IQR 11.3-57.3) months, a statistically significant median change occurred in estimated glomerular filtration rate (eGFR; −8.5 ml/min/1.73 m
2
, IQR −30-7, p = .005) and alkaline phosphatase (ALP; 26 U/l, IQR −11-95, p = .019). In a multiple regression model for eGFR at data collection, baseline eGFR and age were strong explanatory variables.
Incidence of CRBSI, but not treatment strategies, in this nationwide adult IF population correspond well to those reported from specialized centers. Decreased kidney function and abnormal liver test results are frequent findings, and even more so over time, emphasizing the importance of regular monitoring.
Weight loss by ketogenic diet (KD) has gained popularity in management of nonalcoholic fatty liver disease (NAFLD). KD rapidly reverses NAFLD and insulin resistance despite increasing circulating ...nonesterified fatty acids (NEFA), the main substrate for synthesis of intrahepatic triglycerides (IHTG). To explore the underlying mechanism, we quantified hepatic mitochondrial fluxes and their regulators in humans by using positional isotopomer NMR tracer analysis. Ten overweight/obese subjects received stable isotope infusions of: D₇glucose, 13C₄β-hydroxybutyrate and 3-13Clactate before and after a 6-d KD. IHTG was determined by proton magnetic resonance spectroscopy (¹H-MRS). The KD diet decreased IHTG by 31% in the face of a 3% decrease in body weight and decreased hepatic insulin resistance (−58%) despite an increase in NEFA concentrations (+35%). These changes were attributed to increased net hydrolysis of IHTG and partitioning of the resulting fatty acids toward ketogenesis (+232%) due to reductions in serum insulin concentrations (−53%) and hepatic citrate synthase flux (−38%), respectively. The former was attributed to decreased hepatic insulin resistance and the latter to increased hepatic mitochondrial redox state (+167%) and decreased plasma leptin (−45%) and triiodothyronine (−21%) concentrations. These data demonstrate heretofore undescribed adaptations underlying the reversal of NAFLD by KD: That is, markedly altered hepatic mitochondrial fluxes and redox state to promote ketogenesis rather than synthesis of IHTG.
Nonalcoholic fatty liver disease (i.e., increased intrahepatic triglyceride IHTG content), predisposes to type 2 diabetes and cardiovascular disease. Adipose tissue lipolysis and hepatic de novo ...lipogenesis (DNL) are the main pathways contributing to IHTG. We hypothesized that dietary macronutrient composition influences the pathways, mediators, and magnitude of weight gain-induced changes in IHTG.
We overfed 38 overweight subjects (age 48 ± 2 years, BMI 31 ± 1 kg/m
, liver fat 4.7 ± 0.9%) 1,000 extra kcal/day of saturated (SAT) or unsaturated (UNSAT) fat or simple sugars (CARB) for 3 weeks. We measured IHTG (
H-MRS), pathways contributing to IHTG (lipolysis (
H
glycerol) and DNL (
H
O) basally and during euglycemic hyperinsulinemia), insulin resistance, endotoxemia, plasma ceramides, and adipose tissue gene expression at 0 and 3 weeks.
Overfeeding SAT increased IHTG more (+55%) than UNSAT (+15%,
< 0.05). CARB increased IHTG (+33%) by stimulating DNL (+98%). SAT significantly increased while UNSAT decreased lipolysis. SAT induced insulin resistance and endotoxemia and significantly increased multiple plasma ceramides. The diets had distinct effects on adipose tissue gene expression.
Macronutrient composition of excess energy influences pathways of IHTG: CARB increases DNL, while SAT increases and UNSAT decreases lipolysis. SAT induced the greatest increase in IHTG, insulin resistance, and harmful ceramides. Decreased intakes of SAT could be beneficial in reducing IHTG and the associated risk of diabetes.
NAD+ is a redox-active metabolite, the depletion of which has been proposed to promote aging and degenerative diseases in rodents. However, whether NAD+ depletion occurs in patients with degenerative ...disorders and whether NAD+ repletion improves their symptoms has remained open. Here, we report systemic NAD+ deficiency in adult-onset mitochondrial myopathy patients. We administered an increasing dose of NAD+-booster niacin, a vitamin B3 form (to 750–1,000 mg/day; clinicaltrials.govNCT03973203) for patients and their matched controls for 10 or 4 months, respectively. Blood NAD+ increased in all subjects, up to 8-fold, and muscle NAD+ of patients reached the level of their controls. Some patients showed anemia tendency, while muscle strength and mitochondrial biogenesis increased in all subjects. In patients, muscle metabolome shifted toward controls and liver fat decreased even 50%. Our evidence indicates that blood analysis is useful in identifying NAD+ deficiency and points niacin to be an efficient NAD+ booster for treating mitochondrial myopathy.
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•Mitochondrial myopathy patients have NAD+ deficiency in muscle and blood•Niacin is an efficient NAD+ booster in humans•Niacin improves muscle strength and fatty liver in mitochondrial myopathy•Niacin boosts muscle mitochondrial biogenesis and respiratory chain activity in humans
Pirinen et al. report that niacin, a vitamin B3, can efficiently rescue NAD+ levels in the muscle and blood of patients with mitochondrial myopathy, improving disease signs and muscle strength. NAD+ levels increased also in healthy subjects. The evidence suggests that niacin is an effective NAD+ booster in humans.
A carbohydrate-restricted diet is a widely recommended intervention for non-alcoholic fatty liver disease (NAFLD), but a systematic perspective on the multiple benefits of this diet is lacking. Here, ...we performed a short-term intervention with an isocaloric low-carbohydrate diet with increased protein content in obese subjects with NAFLD and characterized the resulting alterations in metabolism and the gut microbiota using a multi-omics approach. We observed rapid and dramatic reductions of liver fat and other cardiometabolic risk factors paralleled by (1) marked decreases in hepatic de novo lipogenesis; (2) large increases in serum β-hydroxybutyrate concentrations, reflecting increased mitochondrial β-oxidation; and (3) rapid increases in folate-producing Streptococcus and serum folate concentrations. Liver transcriptomic analysis on biopsy samples from a second cohort revealed downregulation of the fatty acid synthesis pathway and upregulation of folate-mediated one-carbon metabolism and fatty acid oxidation pathways. Our results highlight the potential of exploring diet-microbiota interactions for treating NAFLD.
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•A low-carbohydrate diet (LCD) improves liver fat metabolism in NAFLD patients•The LCD promotes rapid shifts in the gut microbiota composition of NAFLD patients•The LCD-induced microbial changes are associated with increased circulating folate•The LCD increases folate-dependent one-carbon metabolism gene expression in liver
Mardinoglu et al. use multi-omics to investigate the effects of a carbohydrate-restricted diet in obese NAFLD patients. They show that the diet improves liver fat metabolism, promotes rapid shifts in the gut microbiota, increases circulating folate, and upregulates expression of genes involved in folate-dependent one-carbon metabolism in the liver.
Low mitochondrial number and activity have been suggested as underlying factors in obesity, type 2 diabetes, and metabolic syndrome. However, the stage at which mitochondrial dysfunction manifests in ...adipose tissue after the onset of obesity remains unknown. Here we examined subcutaneous adipose tissue (SAT) samples from healthy monozygotic twin pairs, 22.8-36.2 years of age, who were discordant (ΔBMI >3 kg/m(2), mean length of discordance 6.3 ± 0.3 years, n = 26) and concordant (ΔBMI <3 kg/m(2), n = 14) for body weight, and assessed their detailed mitochondrial metabolic characteristics: mitochondrial-related transcriptomes with dysregulated pathways, mitochondrial DNA (mtDNA) amount, mtDNA-encoded transcripts, and mitochondrial oxidative phosphorylation (OXPHOS) protein levels. We report global expressional downregulation of mitochondrial oxidative pathways with concomitant downregulation of mtDNA amount, mtDNA-dependent translation system, and protein levels of the OXPHOS machinery in the obese compared with the lean co-twins. Pathway analysis indicated downshifting of fatty acid oxidation, ketone body production and breakdown, and the tricarboxylic acid cycle, which inversely correlated with adiposity, insulin resistance, and inflammatory cytokines. Our results suggest that mitochondrial biogenesis, oxidative metabolic pathways, and OXPHOS proteins in SAT are downregulated in acquired obesity, and are associated with metabolic disturbances already at the preclinical stage.
There is substantial inter-individual variability in the risk of non-alcoholic fatty liver disease (NAFLD). Part of which is explained by insulin resistance (IR) (‘MetComp’) and part by common ...modifiers of genetic risk (‘GenComp’). We examined how IR on the one hand and genetic risk on the other contribute to the pathogenesis of NAFLD.
We studied 846 individuals: 492 were obese patients with liver histology and 354 were individuals who underwent intrahepatic triglyceride measurement by proton magnetic resonance spectroscopy. A genetic risk score was calculated using the number of risk alleles in PNPLA3, TM6SF2, MBOAT7, HSD17B13 and MARC1. Substrate concentrations were assessed by serum NMR metabolomics. In subsets of participants, non-esterified fatty acids (NEFAs) and their flux were assessed by D5-glycerol and hyperinsulinemic-euglycemic clamp (n = 41), and hepatic de novo lipogenesis (DNL) was measured by D2O (n = 61).
We found that substrate surplus (increased concentrations of 28 serum metabolites including glucose, glycolytic intermediates, and amino acids; increased NEFAs and their flux; increased DNL) characterized the ‘MetComp’. In contrast, the ‘GenComp’ was not accompanied by any substrate excess but was characterized by an increased hepatic mitochondrial redox state, as determined by serum β-hydroxybutyrate/acetoacetate ratio, and inhibition of hepatic pathways dependent on tricarboxylic acid cycle activity, such as DNL. Serum β-hydroxybutyrate/acetoacetate ratio correlated strongly with all histological features of NAFLD. IR and hepatic mitochondrial redox state conferred additive increases in histological features of NAFLD.
These data show that the mechanisms underlying ‘Metabolic’ and ‘Genetic’ components of NAFLD are fundamentally different. These findings may have implications with respect to the diagnosis and treatment of NAFLD.
The pathogenesis of non-alcoholic fatty liver disease can be explained in part by a metabolic component, including obesity, and in part by a genetic component. Herein, we demonstrate that the mechanisms underlying these components are fundamentally different: the metabolic component is characterized by hepatic oversupply of substrates, such as sugars, lipids and amino acids. In contrast, the genetic component is characterized by impaired hepatic mitochondrial function, making the liver less able to metabolize these substrates.
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•The pathogenesis of NAFLD can be partly explained by a metabolic component and partly by a genetic component.•The mechanisms underlying these components are fundamentally different.•The metabolic component is characterized by a substrate surplus and increased rates of adipose tissue lipolysis and hepatic DNL.•The genetic component is characterized by increased hepatic mitochondrial redox state and inhibition of pathways dependent on TCA cycle activity, such as DNL.•These components additively increase the severity of NAFLD.
Background & Aims Our aims were to develop a method to accurately predict non-alcoholic fatty liver disease (NAFLD) and liver fat content based on routinely available clinical and laboratory data and ...to test whether knowledge of the recently discovered genetic variant in the PNPLA3 gene (rs738409) increases accuracy of the prediction. Methods Liver fat content was measured using proton magnetic resonance spectroscopy in 470 subjects, who were randomly divided into estimation (two thirds of the subjects, n = 313) and validation (one third of the subjects, n = 157) groups. Multivariate logistic and linear regression analyses were used to create an NAFLD liver fat score to diagnose NAFLD and liver fat equation to estimate liver fat percentage in each individual. Results The presence of the metabolic syndrome and type 2 diabetes, fasting serum (fS) insulin, fS-aspartate aminotransferase (AST), and the AST/alanine aminotransferase ratio were independent predictors of NAFLD. The score had an area under the receiver operating characteristic curve of 0.87 in the estimation and 0.86 in the validation group. The optimal cut-off point of −0.640 predicted increased liver fat content with sensitivity of 86% and specificity of 71%. Addition of the genetic information to the score improved the accuracy of the prediction by only <1%. Using the same variables, we developed a liver fat equation from which liver fat percentage of each individual could be estimated. Conclusions The NAFLD liver fat score and liver fat equation provide simple and noninvasive tools to predict NAFLD and liver fat content.
To elucidate the molecular mechanisms underlying non‐alcoholic fatty liver disease (NAFLD), we recruited 86 subjects with varying degrees of hepatic steatosis (HS). We obtained experimental data on ...lipoprotein fluxes and used these individual measurements as personalized constraints of a hepatocyte genome‐scale metabolic model to investigate metabolic differences in liver, taking into account its interactions with other tissues. Our systems level analysis predicted an altered demand for NAD+ and glutathione (GSH) in subjects with high HS. Our analysis and metabolomic measurements showed that plasma levels of glycine, serine, and associated metabolites are negatively correlated with HS, suggesting that these GSH metabolism precursors might be limiting. Quantification of the hepatic expression levels of the associated enzymes further pointed to altered de novo GSH synthesis. To assess the effect of GSH and NAD+ repletion on the development of NAFLD, we added precursors for GSH and NAD+ biosynthesis to the Western diet and demonstrated that supplementation prevents HS in mice. In a proof‐of‐concept human study, we found improved liver function and decreased HS after supplementation with serine (a precursor to glycine) and hereby propose a strategy for NAFLD treatment.
Synopsis
Personalized modeling and metabolic measurements identified altered GSH and NAD+ metabolism as a prevailing feature in NAFLD. These findings suggested a potential treatment strategy for NAFLD patients based on increased oxidation of fat and increased synthesis of GSH.
We developed personalized genome‐scale metabolic models for NAFLD patients.
We found that altered GSH and NAD+ metabolism is a prevailing feature in NAFLD.
Plasma and liver levels of glycine and serine were lower in NAFLD patients.
Supplementation of precursors for glutathione and NAD+ decreased HS in mice.
Serine supplementation decreased liver fat and improved markers of liver function in humans.
Personalized modeling and metabolic measurements identified altered GSH and NAD+ metabolism as a prevailing feature in NAFLD. These findings suggested a potential treatment strategy for NAFLD patients based on increased oxidation of fat and increased synthesis of GSH.
Asbestos is a global occupational health hazard, and exposure to it by inhalation predisposes to interstitial as well as malignant pulmonary morbidity. Over time, asbestos fibers embedded in lung ...tissue can become coated with iron-rich proteins and mucopolysaccharides, after which they are called asbestos bodies (ABs) and can be detected in light microscopy (LM). Bronchoalveolar lavage, a cytological sample from the lower airways, is one of the methods for diagnosing lung asbestosis and related morbidity. Search for ABs in these samples is generally laborious and time-consuming. We describe a novel diagnostic method, which implements deep learning neural network technology for the detection of ABs in bronchoalveolar lavage samples (BALs).
BALs with suspicion of asbestos exposure were scanned as whole slide images (WSIs) and uploaded to a cloud-based virtual microscopy platform with a neural network training interface. The images were used for training and testing a neural network model capable of recognizing ABs. To prioritize the model's sensitivity, we allowed it to also make false-positive suggestions. To test the model, we compared its performance to standard LM diagnostic data as well as the ground truth (GT) number of ABs, which we established by a thorough manual search of the WSIs.
We were able to reach overall sensitivity of 93.4% (95% CI: 90.3-95.7%) in the detection of ABs in comparison to their GT number. Compared to standard LM diagnostic data, our model showed equal to or higher sensitivity in most cases.
Our results indicate that deep learning neural network technology offers promising diagnostic tools for routine assessment of BALs. However, at this stage, a human expert is required to confirm the findings.
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