Synbiotics Alter Fecal Microbiomes, But Not Liver Fat or Fibrosis, in a Randomized Trial of Patients With Nonalcoholic Fatty Liver Disease.

BACKGROUND & AIMS: Dysbiosis of the intestinal microbiota has been associated with nonalcoholic fatty liver disease (NAFLD). We investigated whether administration of a synbiotic combination of probiotic and prebiotic agents affected liver fat content, biomarkers of liver fibrosis, and the composition of the fecal microbiome in patients with NAFLD. METHODS: We performed a double-blind phase 2 trial of 104 patients with NAFLD in the United Kingdom. Participants (mean age, 50.8 ± 12.6 years; 65% men; 37% with diabetes) were randomly assigned to groups given the synbiotic agents (fructo-oligosaccharides, 4 g twice per day, plus Bifidobacterium animalis subspecies lactis BB-12; n = 55) or placebo (n = 49) for 10-14 months. Liver fat content was measured at the start and end of the study by magnetic resonance spectroscopy, and liver fibrosis was determined from a validated biomarker scoring system and vibration-controlled transient elastography. Fecal samples were collected at the start and end of the study, the fecal microbiome were analyzed by 16S ribosomal DNA sequencing. RESULTS: Mean baseline and end-of-study magnetic resonance spectroscopy liver fat percentage values were 32.3% ± 24.8% and 28.5% ± 20.1% in the synbiotic group and 31.3% ± 22% and 25.2% ± 17.2% in the placebo group. In the unadjusted intention-to-treat analysis, we found no significant difference in liver fat reduction between groups (ß = 2.8; 95% confidence interval, -2.2 to 7.8; P = .30). In a fully adjusted regression model (adjusted for baseline measurement of the outcome plus age, sex, weight difference, and baseline weight), only weight loss was associated with a significant decrease in liver fat (ß = 2; 95% confidence interval, 1.5-2.6; P = .03). Fecal samples from patients who received the synbiotic had higher proportions of Bifidobacterium and Faecalibacterium species, and reductions in Oscillibacter and Alistipes species, compared with baseline; these changes were not observed in the placebo group. Changes in the composition of fecal microbiota were not associated with liver fat or markers of fibrosis. CONCLUSIONS: In a randomized trial of patients with NAFLD, 1 year of administration of a synbiotic combination (probiotic and prebiotic) altered the fecal microbiome but did not reduce liver fat content or markers of liver fibrosis. (ClinicalTrials.gov, Number: NCT01680640).

Multi-domain analysis of microvascular flow motion dynamics in NAFLD.

OBJECTIVE: To determine whether analysis of microvascular network perfusion using complexity-based methods can discriminate between groups of individuals at an increased risk of developing CVD. METHODS: Data were obtained from laser Doppler recordings of skin blood flux at the forearm in 50 participants with non-alcoholic fatty liver disease grouped for absence (n = 28) or presence (n = 14) of type 2 diabetes and use of calcium channel blocker medication (n = 8). Power spectral density was evaluated and Lempel-Ziv complexity determined to quantify signal information content at single and multiple time-scales to account for the different processes modulating network perfusion. RESULTS: Complexity was associated with dilatory capacity and respiration and negatively with baseline blood flux and cardiac band power. The relationship between the modulators of flowmotion and complexity of blood flux is shown to change with time-scale improving discrimination between groups. Multiscale Lempel-Ziv achieved best classification accuracy of 86.1%. CONCLUSIONS: Time and frequency domain measures alone are insufficient to discriminate between groups. As cardiovascular disease risk increases, the degree of complexity of the blood flux signal reduces, indicative of a reduced temporal activity and heterogeneous distribution of blood flow within the microvascular network sampled. Complexity-based methods, particularly multiscale variants, are shown to have good discriminatory capabilities.

Flow motion dynamics of microvascular blood flow and oxygenation: Evidence of adaptive changes in obesity and type 2 diabetes mellitus/insulin resistance.

An altered spatial heterogeneity and temporal stability of network perfusion can give rise to a limited adaptive ability to meet metabolic demands. Derangement of local flow motion activity is associated with reduced microvascular blood flow and tissue oxygenation, and it has been suggested that changes in flow motion activity may provide an early indicator of declining, endothelial, neurogenic, and myogenic regulatory mechanisms and signal the onset and progression of microvascular pathophysiology. This short conference review article explores some of the evidence for altered flow motion dynamics of blood flux signals acquired using laser Doppler fluximetry in the skin in individuals at risk of developing or with cardiometabolic disease.

Impaired neurovascular reactivity in the microvasculature of pregnant women with preeclampsia.

INTRODUCTION: PE is associated with maternal vascular dysfunction, leading to serious cardiovascular risk both during and following pregnancy. OBJECTIVE: To assess microvascular reactivity in pregnant women with PE. METHODS: A cross-sectional study was performed in 36 pregnant women with PE and 36 normotensive pregnant women (C) in the third trimester. Skin microvascular blood flow was measured using LDF at rest (RF), during the maximum hyperemic response to brief arterial occlusion (MF) and during the sympathetically mediated constrictor response to deep IBH. RESULTS: In pregnant women with PE, RF was higher [C, 8.1 (4.6); PE, 12.0 (7.6), P<.001; PU perfusion units; median (IQR)] and MF/RF [C, 6.1 (3.7); PE, 3. 9 (4.9) P<.001] and peak CVC lower (P=.009) compared to normotensive controls. The constrictor response to IBH [C, 62.4% (27.9); PE, 33.0% (50.6), P=.008] was reduced in women with PE. In univariate analysis, MF/RF was associated with PE status (r=-.417, P=.0001), systolic (r=-.385, P=.001), and diastolic (r=-.388, P=.001) blood pressure, but not BMI (r=.077, P=.536). CONCLUSIONS: Women with PE are more than three times more likely to exhibit a reduced microvascular reactivity in the third trimester of pregnancy than normotensive pregnant controls. These differences may be attributable in part to an altered sympathetic neural microvascular tone in PE.

Higher body fat percentage is associated with enhanced temperature perception in NAFLD: results from the randomised Wessex Evaluation of fatty Liver and Cardiovascular markers in NAFLD with OMacor thErapy trial (WELCOME) trial.

AIMS/HYPOTHESIS: The effect of n-3 fatty acid treatment on temperature perception as a sensory nerve function modality is uncertain. In patients with non-alcoholic fatty liver disease (NAFLD) both with and without type 2 diabetes, we: (1) tested whether 15-18 months' treatment with 4 g/day of docosahexaenoic plus eicosapentaenoic acid (DHA+EPA) improved hot (HPT) and cold (CPT) temperature perception thresholds and (2) explored factors associated with HPT and CPT, in a randomised, double-blind, placebo-controlled trial. METHODS: The effect of treatment (n = 44) on HPT, CPT and temperature perception index (TPI: difference between HPT and CPT) was measured at the big toe in 90 individuals without neuropathy (type 2 diabetes; n = 30). Participants were randomised 1:1, using sequential numbering, by personnel independent from the trial team. All participants and all members of the research team were blinded to group assignment. Data were collected in the Southampton National Institute for Health Research Biomedical Research Centre. Treatment effects and the independence of associations were testing by regression modelling. RESULTS: Mean ± SD age was 50.9 ± 10.6 years. In men (n = 53) and women (n = 37), HPTs (°C) were 46.1 ± 5.1 and 43.1 ± 6.4 (p = 0.02), CPTs (°C) were 22.7 ± 3.4 and 24.5 ± 3.6 (p = 0.07) and TPIs (°C) were 23.4 ± 7.4 and 18.7 ± 9.5 (p = 0.008), respectively. In univariate analyses, total body fat percentage (measured by dual-energy x-ray absorptiometry [DXA]) was associated with HPT (r = -0.36 p = 0.001), CPT (r = 0.35 p = 0.001) and TPI (r = 0.39 p = 0.0001). In multivariable-adjusted regression models, adjusting for age, sex and other potential confounders, only body fat percentage was independently associated with HPT, CPT or TPI (p = 0.006, p = 0.006 and p = 0.002, respectively). DHA+EPA treatment did not modify HPT, CPT or TPI (p = 0.93, p = 0.44 and p = 0.67, respectively). There were no important adverse effects or side effects reported. CONCLUSIONS/INTERPRETATION: Higher body fat percentage is associated with enhanced temperature perception. There was no benefit of treatment with high-dose n-3 fatty acids on the thresholds to detect hot or cold stimuli. TRIAL REGISTRATION: ClinicalTrials.gov NCT00760513 FUNDING: This work was supported by the National Institute for Health Research through the NIHR Southampton Biomedical Research Unit grant and by a Diabetes UK allied health research training fellowship awarded to KMcC (Diabetes UK. BDA 09/0003937).

An Image-Based Model of Fluid Flow Through Lymph Nodes.

The lymphatic system returns fluid to the bloodstream from the tissues to maintain tissue fluid homeostasis. Lymph nodes distributed throughout the system filter the lymphatic fluid. The afferent and efferent lymph flow conditions of lymph nodes can be measured in experiments; however, it is difficult to measure the flow within the nodes. In this paper, we present an image-based modelling approach to investigating how the internal structure of the node affects the fluid flow pathways within the node. Selective plane illumination microscopy images of murine lymph nodes are used to identify the geometry and structure of the tissue within the node and to determine the permeability of the lymph node interstitium to lymphatic fluid. Experimental data are used to determine boundary conditions and optimise the parameters for the model. The numerical simulations conducted within the model are implemented in COMSOL Multiphysics, a commercial finite element analysis software. The parameter fitting resulted in the estimate that the average permeability for lymph node tissue is of the order of magnitude of [Formula: see text]. Our modelling shows that the flow predominantly takes a direct path between the afferent and efferent lymphatics and that fluid is both filtered and absorbed across the blood vessel boundaries. The amount that is absorbed or extravasated in the model is dependent on the efferent lymphatic lumen fluid pressure.

Impact of high dose n-3 polyunsaturated fatty acid treatment on measures of microvascular function and vibration perception in non-alcoholic fatty liver disease: results from the randomised WELCOME trial.

AIMS/HYPOTHESIS: The effect of n-3 fatty acid treatment on vibration perception thresholds (VPTs) and cutaneous microvascular reactivity is not known. We tested whether: (1) a 15-18 month treatment with high dose (4 g/day) docosahexaenoic (DHA) plus eicosapentaenoic (EPA) acid improved VPT and microvascular reactivity in patients with non-alcoholic fatty liver disease; and (2) there are associations between VPT, microvascular reactivity and metabolic variables. METHODS: In the completed single centre, randomised, parallel group, placebo controlled Wessex Evaluation of fatty Liver and Cardiovascular markers in non-alcoholic fatty liver disease with OMacor thErapy (WELCOME) trial, we tested the effect of DHA+EPA on VPT at 125 Hz (big toe) and the cutaneous hyperaemic response (forearm) to arterial occlusion (ratio of maximum to resting blood flux [MF/RF]). Allocation and dispensing was carried out by an independent research pharmacist; all participants and research team members were blinded to group assignment. RESULTS: In all, 51 and 49 patients were randomised to placebo and DHA+EPA, respectively (mean age 51.4 years). Of these, 32 had type 2 diabetes. Forty-six (placebo) and 47 (DHA+EPA) patients completed the study; there were no important adverse (or unexpected) effects or side effects. In multivariable-adjusted regression models (intention-to-treat analyses), DHA+EPA treatment was associated with an increase in VPT (ß coefficient 1.49 [95% CI 0.04, 2.94], p = 0.04). For VPT, the adjusted mean differences (95% CIs) in the placebo and DHA+EPA treatment groups were -0.725 (-1.71, 0.25) and 0.767 (-0.21, 1.75) m/s(2), respectively. With DHA+EPA treatment, there was no change in MF/RF (ß coefficient 0.07 [95% CI -0.56, 0.70], p = 0.84), the adjusted mean differences (95% CIs) in the placebo and DHA+EPA treatment groups were -0.549 (-1.03, -0.07) and -0.295 (-0.77, 0.18) respectively. VPT was independently associated with age (ß coefficient 0.019 [95% CI 0.010, 0.029], p < 0.0001) and MF/RF (ß coefficient -0.074 [95% CI -0.132, -0.016], p = 0.013), but not with diabetes (p = 0.38). CONCLUSIONS/INTERPRETATION: High dose n-3 fatty acid treatment did not improve measures of microvascular function or vibration perception. Ageing and microvascular reactivity are associated with a measure of peripheral nerve function. TRIAL REGISTRATION: ClinicalTrials.gov NCT00760513. FUNDING: The study was funded by the National Institute for Health Research UK and Diabetes UK.

Treating liver fat and serum triglyceride levels in NAFLD, effects of PNPLA3 and TM6SF2 genotypes: Results from the WELCOME trial.

BACKGROUND & AIMS: Genetic variation in both patatin-like phospholipase domain-containing protein-3 (PNPLA3) (I148M) and the transmembrane 6 superfamily member 2 protein (TM6SF2) (E167K) influences severity of liver disease, and serum triglyceride concentrations in non-alcoholic fatty liver disease (NAFLD), but whether either genotype influences the responses to treatments is uncertain. METHODS: One hundred three patients with NAFLD were randomised to omega-3 fatty acids (DHA+EPA) or placebo for 15-18months in a double blind placebo controlled trial. Erythrocyte enrichment with DHA and EPA was measured by gas chromatography. PNPLA3 and TM6SF2 genotypes were measured by PCR technologies. Multivariable linear regression and analysis of covariance were undertaken to test the effect of genotypes on omega-3 fatty acid enrichment, end of study liver fat percentage and serum triglyceride concentrations. All models were adjusted for baseline measurements of each respective outcome. RESULTS: Fifty-five men and 40 women (Genotypes PNPLA3 I148M, 148I/I=41, 148I/M=43, 148M/M=11; TM6SF2 E167K 167E/E=78, 167E/K+167K/K=17 participants) (mean ± SD age, 51 ± 11 years) completed the trial. Adjusting for baseline measurement, measured covariates and confounders, PNPLA3 148M/M variant was independently associated with percentage of DHA enrichment (B coefficient -1.02 (95% CI -1.97, -0.07), p=0.036) but not percentage of EPA enrichment (B coefficient -0.31 (95% CI -1.38, 0.75), p=0.56). This genotype was also independently associated with end of study liver fat percentage (B coefficient 9.5 (95% CI 2.53, 16.39), p=0.008), but not end of study triglyceride concentration (B coefficient -0.11 (95% CI -0.64, 0.42), p=0.68). CONCLUSIONS: PNPLA3 148M/M variant influences the changes in liver fat and DHA tissue enrichment during the trial but not the change in serum triglyceride concentration.

Effects of purified eicosapentaenoic and docosahexaenoic acids in nonalcoholic fatty liver disease: results from the Welcome* study.

There is no licensed treatment for non-alcoholic fatty liver disease (NAFLD), a condition that increases risk of chronic liver disease, type 2 diabetes and cardiovascular disease. We tested whether 15-18 months treatment with docosahexaenoic acid (DHA) plus eicosapentaenoic acid (EPA) (Omacor/Lovaza) (4 g/day) decreased liver fat and improved two histologically-validated liver fibrosis biomarker scores (primary outcomes). Patients with NAFLD were randomised in a double blind placebo-controlled trial [DHA+EPA(n=51), placebo(n=52)]. We quantified liver fat percentage (%) by magnetic resonance spectroscopy in three liver zones. We measured liver fibrosis using two validated scores. We tested adherence to the intervention (Omacor group) and contamination (with DHA and EPA) (placebo group) by measuring erythrocyte percentage DHA and EPA enrichment (gas chromatography). We undertook multivariable linear regression to test effects of: a) DHA+EPA treatment (ITT analyses) and b) erythrocyte DHA and EPA enrichment (secondary analysis). Median (IQR) baseline and end of study liver fat% were 21.7 (19.3) and 19.7 (18.0) (placebo), and 23.0 (36.2) and 16.3 (22.0), (DHA+EPA). In the fully adjusted regression model there was a trend towards improvement in liver fat% with DHA+EPA treatment (ß=-3.64 (95%CI -8.0,0.8); p=0.1) but there was evidence of contamination in the placebo group and variable adherence to the intervention in the Omacor group. Further regression analysis showed that DHA enrichment was independently associated with a decrease in liver fat% (for each 1% enrichment, ß=-1.70 (95%CI -2.9,-0.5); p=0.007). No improvement in the fibrosis scores occurred. Conclusion. Erythrocyte DHA enrichment with DHA+EPA treatment is linearly associated with decreased liver fat%. Substantial decreases in liver fat% can be achieved with high percentage erythrocyte DHA enrichment in NAFLD. (Hepatology 2014;).

Dynamics of microvascular blood flow and oxygenation measured simultaneously in human skin.

OBJECTIVE: To evaluate the dynamics of skin microvascular blood flow (BF) and tissue oxygenation parameters (OXY) measured simultaneously at the same site using a combined non-invasive BF+OXY+temperature probe. METHODS: Skin BF, oxygenated (oxyHb) and deoxygenated (deoxyHb) haemoglobin and mean oxygen saturation (SO2 ) were measured in 50 healthy volunteers at rest and during perturbation of local blood flow by post-occlusive reactive hyperaemia, sympathetic nervous system-mediated vasoconstriction (deep inspiratory breath-hold) and local skin warming. Signals were analysed in time and frequency domains. RESULTS: The relationship between BF and SO2 over the range of flows investigated was described by a non-linear equation with an asymptote for SO2 of 84% at BF >50 PU. SO2 was independently associated with BF, skin temperature, BMI and age, which together identified 59% of the variance in SO2 (p<0.0001). Fourier analysis revealed periodic low frequency fluctuations in both BF and SO2 , attributable to endothelial (~0.01 Hz), neurogenic (~0.04 Hz) and myogenic (~0.1 Hz) flow motion activity. The frequency coherence between the BF and SO2 signals was greatest in the endothelial and neurogenic frequency bands. CONCLUSIONS: The simultaneous evaluation of microvascular blood flow and oxygenation kinetics in healthy skin provides a platform from which to investigate microvascular impairment in the skin and more generally the pathogenesis of microvascular disease.

Peripheral vascular response to inspiratory breath hold in paediatric homozygous sickle cell disease.

There is increasing evidence that autonomic dysfunction in adults with homozygous sickle cell (haemoglobin SS) disease is associated with enhanced autonomic nervous system-mediated control of microvascular perfusion. However, it is unclear whether such differences are detectable in children with SS disease. We studied 65 children with SS disease [38 boys; median age 7.2 (interquartile range 5.1-10.6) years] and 20 control children without symptoms of SS disease [8 boys; 8.7 (5.5-10.8) years] and recorded mean arterial blood pressure (ABP) and daytime haemoglobin oxygen saturation (S(pO(2))). Cutaneous blood flux at rest (RBF) and during the sympathetically activated vasoconstrictor response to inspiratory breath hold (IBH) were measured in the finger pulp of the non-dominant hand using laser Doppler fluximetry. Local factors mediating flow motion were assessed by power spectral density analysis of the oscillatory components of the laser Doppler signal. The RBF measured across the two study groups was negatively associated with age (r = -0.25, P < 0.0001), ABP (r = -0.27, P = 0.02) and daytime S(pO(2)) (r = -0.30, P = 0.005). Children with SS disease had a higher RBF (P = 0.005) and enhanced vasoconstrictor response to IBH (P = 0.002) compared with control children. In children with SS disease, higher RBF was associated with an increase in the sympathetic interval (r = -0.28, P = 0.022). The SS disease status, daytime S(pO(2)) and age explained 22% of the variance in vasoconstrictor response to IBH (P < 0.0001). Our findings suggest that blood flow and blood flow responses in the skin of young African children with SS disease differ from those of healthy control children, with increased resting peripheral blood flow and increased sympathetic stimulation from a young age in SS disease. They further suggest that the laser Doppler flowmetry technique with inspiratory breath hold manoeuvre appears to be robust for use in young children with SS disease, to explore interactions between S(pO(2)), ABP and autonomic function with clinical complications, e.g. skin ulceration.

Laser doppler blood flow imaging using a CMOS imaging sensor with on-chip signal processing.

The first fully integrated 2D CMOS imaging sensor with on-chip signal processing for applications in laser Doppler blood flow (LDBF) imaging has been designed and tested. To obtain a space efficient design over 64 × 64 pixels means that standard processing electronics used off-chip cannot be implemented. Therefore the analog signal processing at each pixel is a tailored design for LDBF signals with balanced optimization for signal-to-noise ratio and silicon area. This custom made sensor offers key advantages over conventional sensors, viz. the analog signal processing at the pixel level carries out signal normalization; the AC amplification in combination with an anti-aliasing filter allows analog-to-digital conversion with a low number of bits; low resource implementation of the digital processor enables on-chip processing and the data bottleneck that exists between the detector and processing electronics has been overcome. The sensor demonstrates good agreement with simulation at each design stage. The measured optical performance of the sensor is demonstrated using modulated light signals and in vivo blood flow experiments. Images showing blood flow changes with arterial occlusion and an inflammatory response to a histamine skin-prick demonstrate that the sensor array is capable of detecting blood flow signals from tissue.

Spotlight issue: MicroRNAs in the microcirculation--from cellular mechanisms to clinical markers.

This spotlight issue of Microcirculation contains four state-of-the-art review articles on the role of microRNAs (miRNAs), a class of endogenous, highly conserved, small, non-coding RNAs that regulate gene expression at the post transcriptional level, and can act as key regulators of cellular mechanisms within the microcirculation. The expert reviews address issues, such as the role of miRNAs in determining endothelial cell differentiation and lineage commitment, the physiological role of miRNAs as critical modulators of endothelial cell proliferation, apoptosis and in angiogenesis, and their aberrant expression in different vascular disorders. The reviews also explore the prognostic value of miRNAs in cardiovascular disease and how they may serve both as a therapeutic target and clinical biomarker in the future. This cutting edge edition of the journal Microcirculation highlights the progress that has been made in this new and challenging research area.

The microcirculation: a target for developmental priming.

There is increasing evidence that the early life environment, of which nutrition is a key component, acts through developmental adaptations to set the capacity of cardiovascular and metabolic pathways, and ultimately the limits to physiological challenges in later life. Suboptimal maternal nutrition and fetal growth result in reduced microvascular perfusion and functional dilator capacity, which are strongly associated with later development of obesity, type 2 diabetes, and hypertension. These conditions are also linked to microvascular rarefaction and remodeling that together limit capillary recruitment, reduce exchange capacity and increase diffusion distances of metabolic substrates, and increase local and overall peripheral resistance. Changes in small vessel structure and function may be seen very early, long before the onset of overt cardiovascular and metabolic disease, and may thus be a target for early therapeutic and lifestyle intervention strategies. This article explores how a disadvantageous microvascular phenotype may result from perinatal priming and how developmental plasticity may become an important and additional risk determinant in susceptibility to cardiometabolic disease in adult life.

Functional dilator capacity is independently associated with insulin sensitivity and age in central obesity and is not improved by high dose statin treatment.

OBJECTIVE: To test the hypothesis that: (i) functional microvascular dilator capacity is independently associated with insulin sensitivity and age in individuals with central adiposity at risk of cardiovascular disease (CVD); and (ii) functional microvascular dilator capacity is improved by high dose statin treatment. METHODS: Functional dilator capacity (measured as change in laser Doppler blood flux from baseline during post occlusive reactive hyperemia [peak flux%resting flux; PF%RF] and flowmotion (power spectral density [PSD] analysis)) were assessed in 40 people with central adiposity and one or more other CVD risk factors. Measurements were made at rest and during acute hyperinsulinaemia before and six months after high dose atorvastatin (40 mg daily) or placebo. RESULTS: Insulin-induced change in PF%RF was independently associated with insulin sensitivity (M/I) (r = 0.46 p = 0.02) and age (r = -0.46 p = 0.02), which together explained almost half of the variance in PF%RF (adjusted r² = 0.37, p = 0.008). Whilst atorvastatin decreased LDL cholesterol by 51% (p < 0.001), PF%RF and flowmotion remained unchanged. CONCLUSIONS: Insulin sensitivity and age are independently associated with an insulin-induced change in functional microvascular dilator capacity in individuals with central adiposity at risk of CVD. Dilator capacity is not improved by six months high dose statin treatment.

Maternal high-fat feeding primes steatohepatitis in adult mice offspring, involving mitochondrial dysfunction and altered lipogenesis gene expression.

UNLABELLED: Nonalcoholic fatty liver disease (NAFLD) describes an increasingly prevalent spectrum of liver disorders associated with obesity and metabolic syndrome. It is uncertain why steatosis occurs in some individuals, whereas nonalcoholic steatohepatitis (NASH) occurs in others. We have generated a novel mouse model to test our hypothesis: that maternal fat intake contributes to the development of NAFLD in adult offspring. Female mice were fed either a high-fat (HF) or control chow (C) diet before and during gestation and lactation. Resulting offspring were fed either a C or a HF diet after weaning, to generate four offspring groups; HF/HF, HF/C, C/HF, C/C. At 15 weeks of age, liver histology was normal in both the C/C and HF/C offspring. Kleiner scoring showed that although the C/HF offspring developed nonalcoholic fatty liver, the HF/HF offspring developed NASH. At 30 weeks, histological analysis and Kleiner scoring showed that both the HF/C and C/HF groups had NAFLD, whereas the HF/HF had a more severe form of NASH. Therefore, exposure to a HF diet in utero and during lactation contributes toward NAFLD progression. We investigated the mechanisms by which this developmental priming is mediated. At 15 weeks of age, hepatic mitochondrial electron transport chain (ETC) enzyme complex activity (I, II/III, and IV) was reduced in both groups of offspring from HF-fed mothers (HF/C and HF/HF). In addition, measurement of hepatic gene expression indicated that lipogenesis, oxidative stress, and inflammatory pathways were up-regulated in the 15-week-old HF/C and HF/HF offspring. CONCLUSION: Maternal fat intake contributes toward the NAFLD progression in adult offspring, which is mediated through impaired hepatic mitochondrial metabolism and up-regulated hepatic lipogenesis.

Dysregulated Neurovascular Control Underlies Declining Microvascular Functionality in People With Non-alcoholic Fatty Liver Disease (NAFLD) at Risk of Liver Fibrosis.

BACKGROUND/AIMS: Increasing evidence shows that non-alcoholic fatty liver disease (NAFLD) is associated with dysregulation of microvascular perfusion independently of established cardio-metabolic risk factors. We investigated whether hepatic manifestations of NAFLD such as liver fibrosis and liver fat are associated with microvascular hemodynamics through dysregulation of neurovascular control. METHODS: Microvascular dilator (post-occlusive reactive hyperemia) and sympathetically mediated constrictor (deep inspiratory breath-hold) responses were measured at the forearm and finger, respectively, using laser Doppler fluximetry. Non-linear complexity-based analysis was used to assess the information content and variability of the resting blood flux (BF) signals, attributable to oscillatory flow-motion activity, and over multiple sampling frequencies. RESULTS: Measurements were made in 189 adults (113 men) with NAFLD, with (n = 65) and without (n = 124) type 2 diabetes mellitus (T2DM), age = 50.9 ± 11.7 years (mean ± SD). Microvascular dilator and constrictor capacity were both negatively associated with age (r = -0.178, p = 0.014, and r = -0.201, p = 0.007, respectively) and enhanced liver fibrosis (ELF) score (r = -0.155, p = 0.038 and r = -0.418, p < 0.0001, respectively). There was no association with measures of liver fat, obesity or T2DM. Lempel-Ziv complexity (LZC) and sample entropy (SE) of the BF signal measured at the two skin sites were associated negatively with age (p < 0.01 and p < 0.001) and positively with ELF score (p < 0.05 and p < 0.0001). In individuals with an ELF score ≥7.8 the influence of both neurogenic and respiratory flow-motion activity on LZC was up-rated (p < 0.0001). CONCLUSION: Altered microvascular network functionality occurs in adults with NAFLD suggesting a mechanistic role for dysregulated neurovascular control in individuals at risk of severe liver fibrosis.

Age and cigarette smoking are independently associated with the cutaneous vascular response to local warming.

PURPOSE: To investigate the relative impacts of age and cigarette smoking on cutaneous blood flow and flow motion. EXPERIMENTAL DESIGN: Skin blood flux was measured before and during the hyperaemic response to thermal warming of the skin to 43 degrees C using laser Doppler fluximetry (LDF) in 28 habitual smokers (5.4 [11.4] (median [IQR]) pack years; pack years = packs/day x duration of smoking habit), aged between 18 and 63 years and their age, sex and body mass index. Flow motion was assessed using Fourier analysis of the LDF signal. RESULTS: Mean and total hyperaemic (area under the flux curve, AUC(10)) response during warming were reduced in smokers compared with their non-smoking controls (P<0.05). Attenuation of the response to warming in smokers was associated with a reduction in relative spectral power around 0.01 Hz, reflecting a reduced endothelial/metabolic activity (P<0.04). In regression modelling with AUC(10) as the outcome, and smoking (yes/no), age, sex and BMI, as explanatory variables, age (P<0.0001) and smoking (P=0.018) were independently associated with the hyperaemic response and together accounted for 31% of the variance in AUC(10). CONCLUSIONS: Age and smoking are associated with approximately one-third of the variance in the endothelium-associated microvascular vasomotor activity in habitual smokers.

Attractor Reconstruction Analysis for Blood Flow Signals.

Attractor reconstruction analysis has been previously used to determine changes in the shape and variability of fairly periodic signals such as arterial blood pressure signals and electroencephalogram signals, providing a two-dimensional attractor with features like density and symmetry. Since BF signals are fairly periodic and quasi-stationary, we set out to investigate whether attractor reconstruction method could be applied in signals derived from the microvascular perfusion. We describe the basis and the implementation of attractor reconstruction analysis of the microvascular blood flux (BF) signals recorded from the skin of 15 healthy male volunteers, age 29.2 ± 8.1y (mean ± SD). The efficacy of attractor reconstruction analysis (ARA) as a potential method of identifying changes in the microvascular function is evaluated in two haemodynamic steady states, at 33°C, and during warming at 43°C to generate a local thermal hyperaemia (LTH). Our findings show a significant drop of the maximal density derived from the ARA, during increased flow and that there was good discrimination of the blood flow signals between the two haemodynamic steady states, having good classification accuracy (80%). This study shows that ARA of BF signals can identify different microvascular functional states and thus has a potential for the clinical assessment and diagnosis of pathophysiological condition.