Evaluation of measured and calculated small dense low-density lipoprotein in capillary blood and association with the metabolic syndrome.

BACKGROUND AND AIMS: Small-dense-low-density-lipoprotein cholesterol (sdLDL-C) is proatherogenic and not commonly measured. The aims were to evaluate capillary blood and its stability for sdLDL-C measurement and measure sdLDL-C in patients with metabolic syndrome (MS). METHODS: 182 patients were studied (49 with MS). sdLDL-C was measured by electrophoresis (LipoPrint®), direct measurement (Roche Diagnostics) and Sampson equation. Intima-media thickness (IMT) and presence of atheroma was evaluated. sdLDL-C was compared in paired venous and capillary blood according to CLSI-EP09c (n = 40). sdLDL-C stability was studied after 24 h at room temperature (RT). RESULTS: sdLDL-C in capillary blood and venous blood showed agreement with the direct measurement (bias: 4.17 mg/dL, LOA 95 %:-5.66; 13.99) and estimation (bias:8.12 mg/dL, LOA 95 %:-8.59; 24.82). sdLDL-C is stable in capillary blood for 24 h at RT. The electrophoretic method yielded lower (p < 0.05) sdLDL-C than the equation or direct measurement. Patients with MS had (p < 0.05) higher sdLDL-C (%) than patients without MS. Patients with atheroma plaques had higher sdLDL-C (p < 0.05). Estimated sdLDL-C correlated with IMT (r = 0.259, p < 0.001). CONCLUSIONS: Capillary blood is an alternative to venous blood for sdLDL-C measurement and is stable for 24 h after collection. Estimated and directly measured sdLDL-C associate with the MS being accessible tools for cardiovascular risk assessment.

Uroguanylin prevents hepatic steatosis, mitochondrial dysfunction and fibrosis in obesity-associated NAFLD.

BACKGROUND: The biological mediators supporting the resolution of liver steatosis, inflammation and fibrosis after bariatric surgery in patients with obesity and NAFLD remain unclear. We sought to analyze whether uroguanylin and guanylin, two gut hormones involved in the regulation of satiety, food preference and adiposity, are involved in the amelioration of obesity-associated NAFLD after bariatric surgery. METHODS: Proguanylin (GUCA2A) and prouroguanylin (GUCA2B) were measured in 214 participants undergoing bariatric surgery with biopsy-proven NAFLD diagnosis. Pathways involved in lipid metabolism, mitochondrial network and fibrogenesis were evaluated in liver biopsies (n = 137). The effect of guanylin and uroguanylin on these metabolic functions was assessed in HepG2 hepatocytes and LX-2 hepatic stellate cells (HSC) under lipotoxic and profibrogenic conditions. RESULTS: Plasma and hepatic expression of GUCA2B were decreased in obesity-associated NAFLD. Both GUCA2A and GUCA2B levels were increased after sleeve gastrectomy and Roux-en-Y gastric bypass in parallel to the improved liver function. The liver of patients with type 2 diabetes showed impaired mitochondrial ß-oxidation, biogenesis, dynamics as well as increased fibrosis. Uroguanylin diminished the lipotoxicity in palmitate-treated HepG2 hepatocytes, evidenced by decresased steatosis and lipogenic factors, as well as increased mitochondrial network expression, AMPK-induced ß-oxidation and oxygen consumption rate. Additionally, uroguanylin, but not guanylin, reversed HSC myofibroblast transdifferentiation as well as fibrogenesis after TGF-ß1 stimulation. CONCLUSIONS: Uroguanylin constitutes a protective factor against lipotoxicity, mitochondrial dysfunction and fibrosis. Increased GUCA2B levels might contribute to improve liver injury in patients with obesity-associated NAFLD after bariatric surgery.

Biochemical biomarkers for multiple sclerosis.

INTRODUCTION: Multiple sclerosis (MS) is the most frequent demyelinating disease of the central nervous system. Although there is currently no definite cure for MS, new therapies have recently been developed based on a continuous search for new biomarkers. DEVELOPMENT: MS diagnosis relies on the integration of clinical, imaging and laboratory findings as there is still no singlepathognomonicclinical feature or diagnostic laboratory biomarker. The most commonly laboratory test used is the presence of immunoglobulin G oligoclonal bands (OCB) in cerebrospinal fluid of MS patients. This test is now included in the 2017 McDonald criteria as a biomarker of dissemination in time. Nevertheless, there are other biomarkers currently in use such as kappa free light chain, which has shown higher sensitivity and specificity for MS diagnosis than OCB. In addition, other potential laboratory tests involved in neuronal damage, demyelination and/or inflammation could be used for detecting MS. CONCLUSIONS: CSF and serum biomarkers have been reviewed for their use in MS diagnosis and prognosis to stablish an accurate and prompt MS diagnosis, crucial to implement an adequate treatment and to optimize clinical outcomes over time.

Circulating Concentrations of GDF11 are Positively Associated with TSH Levels in Humans.

Growth differentiation factor 11 (GDF11) is a member of the transforming growth factor (TGF)-ß superfamily which declines with age and has been proposed as an anti-aging factor with regenerative effects in skeletal muscle in mice. However, recent data in humans and mice are conflicting, casting doubts about its true functional actions. The aim of the present study was to analyze the potential involvement of GFD11 in energy homeostasis in particular in relation with thyroid hormones. Serum concentrations of GDF11 were measured by enzyme-linked immunosorbent assay (ELISA) in 287 subjects. A highly significant positive correlation was found between GDF11 and thyroid-stimulating hormone (TSH) concentrations (r = 0.40, p < 0.001). Neither resting energy expenditure (REE) nor REE per unit of fat-free mass (REE/FFM) were significantly correlated (p > 0.05 for both) with GDF11 levels. In a multiple linear regression analysis, the model that best predicted logGDF11 included logTSH, leptin, body mass index (BMI), age, and C-reactive protein (logCRP). This model explained 37% of the total variability of logGDF11 concentrations (p < 0.001), with only logTSH being a significant predictor of logGDF11. After segregating subjects by TSH levels, those within the low TSH group exhibited significantly decreased (p < 0.05) GDF11 concentrations as compared to the normal TSH group or the high TSH group. A significant correlation of GDF11 levels with logCRP (r = 0.19, p = 0.025) was found. GDF11 levels were not related to the presence of hypertension or cardiopathy. In conclusion, our results show that circulating concentrations of GDF11 are closely associated with TSH concentrations and reduced in subjects with low TSH levels. However, GDF11 is not related to the regulation of energy expenditure. Our data also suggest that GDF11 may be involved in the regulation of inflammation, without relation to cardiac function. Further research is needed to elucidate the role of GDF11 in metabolism and its potential involvement in thyroid pathophysiology.

Ghrelin Reduces TNF-α-Induced Human Hepatocyte Apoptosis, Autophagy, and Pyroptosis: Role in Obesity-Associated NAFLD.

Context: Human obesity is associated with increased circulating TNF-α, a proinflammatory cytokine that induces hepatocyte cell death. Objective: The potential beneficial effects of acylated and desacyl ghrelin in the progression of nonalcoholic fatty liver disease (NAFLD) to nonalcoholic steatohepatitis in obesity via the inhibition of TNF-α-induced hepatocyte apoptosis, autophagic cell death, and pyroptosis were investigated. Design, Settings, and Participants: Plasma ghrelin isoforms and TNF-α were measured in 158 participants, and hepatocyte cell death was evaluated in liver biopsies from 76 patients with morbid obesity undergoing bariatric surgery with available liver echography and pathology analysis. The effect of acylated and desacyl ghrelin on basal and TNF-α-induced cell death was determined in vitro in human HepG2 hepatocytes. Results: Circulating TNF-α and the acylated/desacyl ghrelin ratio were increased, whereas desacyl ghrelin levels were decreased in patients with obesity and NAFLD. Six months after bariatric surgery, decreased acylated/desacyl ghrelin levels, and improved hepatic function were found. Patients with obesity and type 2 diabetes showed increased hepatic ghrelin O-acyltransferase transcripts as well as an increased hepatic apoptosis, pyroptosis, and compromised autophagy. In HepG2 hepatocytes, acylated and desacyl ghrelin treatment reduced TNF-α-induced apoptosis, evidenced by lower caspase-8 and caspase-3 cleavage, as well as TUNEL-positive cells and pyroptosis, revealed by decreased caspase-1 activation and lower high-mobility group box 1 expression. Moreover, acylated ghrelin suppressed TNF-α-activated hepatocyte autophagy, as evidenced by a decreased LC3B-II/I ratio and increased p62 accumulation via AMPK/mTOR. Conclusions: Ghrelin constitutes a protective factor against hepatocyte cell death. The increased acylated/desacyl ghrelin ratio in patients with obesity and NAFLD might constitute a compensatory mechanism to overcome TNF-α-induced hepatocyte apoptosis, autophagy, and pyroptosis.

Factors related to increased resting energy expenditure in men with liver cirrhosis.

OBJECTIVE: Hypermetabolism in cirrhosis is associated with a high risk of complications and mortality. However, studies about underlying mechanisms are usually focussed on isolated potential determinants and specific etiologies, with contradictory results. We aimed at investigating differences in nutrition, metabolic hormones, and hepatic function between hypermetabolic and nonhypermetabolic men with cirrhosis of the liver. PATIENTS AND METHODS: We prospectively enrolled 48 male cirrhotic inpatients. We evaluated their resting energy expenditure (REE) and substrate utilization by indirect calorimetry, body composition by dual-energy X-ray absorptiometry, liver function, and levels of major hormones involved in energy metabolism by serum sample tests. Patients with ascites, specific metabolic disturbances, and hepatocellular carcinoma were excluded. RESULTS: REE and REE adjusted per fat-free mass (FFM) were significantly increased in cirrhotic patients. Overall, 58.3% of cirrhotic patients were classified as hypermetabolic. Groups did not differ significantly in age, etiology of cirrhosis, liver function, presence of ascites, use of diuretics, ß-blockers, or presence of transjugular intrahepatic portosystemic shunts. Hypermetabolic cirrhotic patients had lower weight, BMI (P<0.05), nonprotein respiratory quotient (P<0.01), leptin (P<0.05), and leptin adjusted per fat mass (FM) (P<0.05), but higher FFM% (P<0.05) and insulin resistance [homeostatic model assessment-insulin resistance (HOMA-IR)] (P<0.05). Only HOMA-IR, leptin/FM, and FFM% were independently related to the presence of hypermetabolism. CONCLUSION: Hypermetabolic cirrhotic men are characterized by lower weight, higher FFM%, insulin resistance, and lower leptin/FM when compared with nonhypermetabolic men. HOMA-IR, FFM%, and leptin/FM were independently associated with hypermetabolism, and may serve as easily detectable markers of this condition in daily clinical practice.

Insulin levels are decreased in the cerebrospinal fluid of women with prodomal Alzheimer's disease.

Previous studies have failed to reach consensus on insulin levels in cerebrospinal fluid of Alzheimer's disease (AD) patients and on its relation to pathological features. We performed a new analysis in patients at different stages of AD, and investigated the relationship of insulin levels with biochemical disease markers and with cognitive score. We included 99 patients from our Memory Clinic (Karolinska University Hospital, Sweden), including: 27 patients with mild AD, 13 that progressed from mild cognitive impairment (MCI) to AD in two years time, 26 with MCI stable after two years, and 33 with subjective cognitive impairment. Insulin was significantly decreased in the cerebrospinal fluid of both women and men with mild AD. Insulin deficits were seen in women belonging to both MCI groups, suggesting that this occurs earlier than in men. Insulin was positively associated with amyloid-ß 1-42 (Aß1-42) levels and cognitive score. Furthermore, total-tau/(Aß1-42*insulin) ratio showed strikingly better sensitivity and specificity than the total-tau/Aß1-42 ratio for early AD diagnosis in women.

Impaired adiponectin-AMPK signalling in insulin-sensitive tissues of hypertensive rats.

AIMS: Adiponectin improves insulin sensitivity by decreasing lipid accumulation in insulin-sensitive tissues. The aim of this study was to investigate whether these effects are altered in hypertension. MAIN METHODS: Adiponectin receptors (AdipoR1 and AdipoR2) and adiponectin-related enzymes were measured by real-time PCR and Western-blot in insulin-sensitive tissues of 10-week-old male spontaneously hypertensive rats (SHR). Intrahepatic and intramyocellular triglycerides were determined by enzymatic methods. KEY FINDINGS: SHR showed overweight, dyslipidemia, glucose intolerance and insulin resistance. Circulating concentrations of adiponectin as well as the mRNA and protein expression of adiponectin in epididymal and subcutaneous fat depots were significantly increased in hypertensive rats. Adiponectin mRNA levels were strongly associated with PPARgamma mRNA levels in both epididymal (r=0.54, P<0.05) and subcutaneous (r=0.93, P<0.0001) fat. The expression of AdipoR1 and AdipoR2, acetyl-CoA carboxylase (ACC), as well as carnitine palmitoyl transferase 1 (CPT1), were increased in skeletal muscle of SHR. These changes were not observed in the liver of SHR. In addition, in spite of the hyperadiponectinemia, SHR showed similar activation of AMP-activated protein kinase (AMPK) and a lower phosphorylation degree of its downstream ACC in liver and skeletal muscle. Accordingly, SHR exhibited a significant increase in intrahepatic (approximately 40%) and intramyocellular (approximately 60%) lipid accumulation. SIGNIFICANCE: These findings suggest that dysregulation of the adiponectin downstream effectors contributes to increased intrahepatic and intramyocellular triglycerides in SHR. Hyperadiponectinemia together with overexpression of adiponectin receptors in skeletal muscle may reflect a defective compensatory mechanism to overcome adiponectin resistance in hypertensive rats.

Plasma osteopontin levels and expression in adipose tissue are increased in obesity.

CONTEXT: Obesity acts as a cardiovascular risk factor by mechanisms that are not fully understood. Osteopontin (OPN) is a proinflammatory mediator involved in tissue remodeling that plays a role in atherosclerosis and diabetes. OBJECTIVE: The aim of the present study was to compare the circulating concentrations of OPN and its mRNA expression in omental adipose tissue of lean, overweight, and obese individuals and to analyze the effect of weight loss. SUBJECTS AND METHODS: Plasma concentrations of OPN were measured in 77 volunteers. OPN mRNA expression in omental adipose tissue obtained from 12 women was quantified by real-time PCR. In addition, the concentrations of OPN in 12 obese men were measured before and after weight loss following a dietetic program. SETTING: The study was conducted at a University Hospital. RESULTS: Obese and overweight patients exhibited significantly increased circulating OPN concentrations as compared with lean subjects (obese 72.6 +/- 28.5, overweight 68.2 +/- 20.8, lean 42.7 +/- 27.9 ng/ml; P < 0.001). A significant positive correlation was found between OPN levels and body fat (r = 0.45; P < 0.0001). Obese individuals showed significantly increased (P < 0.05) mRNA expression of OPN in omental adipose tissue as compared with lean volunteers, which was further increased in obese diabetic patients. Diet-induced weight loss significantly decreased OPN concentrations from 64.7 +/- 22.1 to 36.6 +/- 20.1 ng/ml (P = 0.006). CONCLUSIONS: These findings represent the first observation that plasma OPN and mRNA expression of OPN in omental adipose tissue are increased in overweight/obese patients with the latter being further elevated in obesity-associated diabetes. Moreover, weight loss reduces OPN concentrations, which may contribute to the beneficial effects accompanying weight reduction. Measurement of OPN might be useful for evaluating the outcomes of various clinical interventions for obesity-related cardiovascular diseases.

Bimodal effect of nitric oxide in the enzymatic activity of indoleamine 2,3-dioxygenase in human monocytic cells.

Indoleamine 2,3-dioxygenase (IDO) is an enzyme that depletes l-tryptophan, which provokes a decreased T cell response. This enzyme is expressed in human placenta, and can be also induced in many cell types such as monocytes, where endothelial (eNOS) and inducible (iNOS) nitric oxide synthases are also expressed. Previous studies have shown that nitric oxide (NO) inhibits IDO activity, which could cause a suppression of the biological function of IDO when both enzymes are coexpressed. As NO can exert different effects depending on several factors such as its concentration, we studied the effect of low concentrations of NO in the IDO activity in the U-937 and THP-1 monocytic cell lines. Results demonstrated that NO caused a bimodal effect in IDO function in IFN-gamma-stimulated monocytic cells: while high micromolar concentrations of the NO donors SIN-1 and DETA-NO decreased IDO activity, low micromolar concentrations of these NO donors increased IDO activity. Related to this, the NOS inhibitors L-NMMA and aminoguanidine, and the calmodulin antagonist W7 also decreased IDO activity. The effect of NO in IDO activity was not through cGMP production. Immunoprecipitation analysis showed a nitration of the IDO protein in unstimulated and stimulated U-937 and THP-1 cells. However, in monocyte-derived macrophages, with a higher NO production, aminoguanidine increased IDO activity, but the NOS substrate arginine decreased IDO activity. Considering the role of IDO in suppression, these results suggest a function in tolerance of the NOS enzymes depending on the NO production.