Circulating fetuin-A and risk of ischemic stroke in women

Mitochondrial Lipid Homeostasis at the Crossroads of Liver and Heart Diseases

The prevalence of NAFLD (non-alcoholic fatty liver disease) is a rapidly increasing problem, affecting a huge population around the globe. However, CVDs (cardiovascular diseases) are the most common cause of mortality in NAFLD patients. Atherogenic dyslipidemia, characterized by plasma hypertriglyceridemia, increased small dense LDL (low-density lipoprotein) particles, and decreased HDL-C (high-density lipoprotein cholesterol) levels, is often observed in NAFLD patients. In this review, we summarize recent genetic evidence, proving the diverse nature of metabolic pathways involved in NAFLD pathogenesis. Analysis of available genetic data suggests that the altered operation of fatty-acid β-oxidation in liver mitochondria is the key process, connecting NAFLD-mediated dyslipidemia and elevated CVD risk. In addition, we discuss several NAFLD-associated genes with documented anti-atherosclerotic or cardioprotective effects, and current pharmaceutical strategies focused on both NAFLD treatment and reduction of CVD risk.

Tengdan Capsule Prevents Hypertensive Kidney Damage in SHR by Inhibiting Periostin-Mediated Renal Fibrosis

BACKGROUND: Hypertension-induced renal damage is a serious and complex condition that has not been effectively treated by conventional blood pressure-lowering drugs. Tengdan capsule (TDC) is a China FDA-approved compound herbal medicine for treating hypertension; however, its chemical basis and pharmacological efficacy have not been fully investigated in a preclinical setting.

METHODS: High-performance liquid chromatography (HPLC) was used to identify and quantify the major chemical components of TDC extracted from ultrapure water. Adult spontaneously hypertensive rats (SHR) and age/sex-matched Wistar Kyoto normotensive rats (WKY) were both treated with TDC, losartan, or saline for one month, and their blood pressure (BP) was monitored at the same time by tail-cuff BP system. Biochemical indexes such as urine creatinine (CRE) and blood urea nitrogen (BUN) were determined. Kidney tissue sections were examined with (H&E), and Masson staining to evaluate the pathological effect of TDC on SHR’s kidneys. After TDC treatment, the differentially expressed proteins in the kidneys of SHR were identified by the TMT-based quantitative proteomics analysis, which may provide the targets and possible mechanisms of TDC action. In addition, Western blot analysis, RT-qPCR, and ELISA assays were carried out to further verify the proteomics findings. Finally, two different models involving in vitro renal injuries were established using human kidney HEK293 cells; and the molecular mechanism of TDC kidney protection was demonstrated.

RESULTS: Seven chemical compounds, namely Notoginsenoside R1, Ginsenoside RG1, Ginsenoside Re, Ginsenoside Rb1, Sodium Danshensu, Protocatechualdehyde, and Salvianolic acid B, were identified and quantified from the water-soluble extracts of TDC by HPLC. In vivo study using rats showed that TDC effectively reduced BP, BUN, and CRE levels and attenuated renal fibrosis in SHR, and ameliorated damage to the kidneys. Proteomics and subsequent bioinformatics analyses indicated that periostin-mediated inflammatory response and TGFβ/Smad signaling pathway proteins were closely related to the therapeutic effect of TDC in rat kidneys. Western blot analysis and RT-qPCR showed that TDC markedly downregulated the mRNA and protein expression of periostin in renal tissues compared to the untreated SHR. In addition, TGF-β and COL1A1 mRNA levels also decreased in SHR renal tissues following TDC treatment. In vitro studies showed that low to medium doses of TDC down-regulated the expression of periostin in the injury model of HEK293 cell. In addition, medium to high doses of TDC significantly inhibited collagen deposition in TGFβ1-induced HEK293 cell fibrosis.

CONCLUSIONS: Major components from the compound herbal medicine Tengdan Capsule are identified and quantified. TDC effectively lowers blood pressure and protects against renal damage caused by hypertension in SHR. Mechanistically, TDC blocks periostin by regulating the TGF-β/Smad signaling pathway in the kidney, both in vivo and in vitro. Preventing periostin-mediated renal fibrosis and inflammation might be a promising strategy for treating a hypertensive renal injury.

Fetuin-A – Alpha2-Heremans-Schmid Glycoprotein: From Structure to a Novel Marker of Chronic Diseases Part 2. Fetuin-A – A Marker of Insulin Resistance and Related Chronic Diseases

Fetuin-A is a secretory liver glycoprotein with multiple physiological functions such as regulation of insulin resistance, tissue calcification, bone metabolism, cellular proteolytic activity, and self-proliferative signaling.

Fetuin-A is a unique molecule which binds to the insulin receptor, modulating its sensitivity, and transducing “the physiological conditions” (serum levels of the metabolites like glucose, free fatty acids, inflammatory signals) from outside into inside the cells. Plasma fetuin-A levels correlate with reduced glucose tolerance and insulin resistance. Impaired insulin sensitivity leads to the development of metabolic syndrome, an increased risk for type 2 diabetes (T2DM), dyslipidaemias and cardiovascular diseases (CVDs). Furthermore, fetuin-A inversely correlates with inflammatory and activation biomarkers, e.g. in patients with T2DM. Thus, circulatory fetuin-A levels may have plausible predictive importance as a biomarker of risk of diabetes and negative acute phase protein. Dysregulated, it plays a crucial role in the pathogenesis of some metabolic disorders and clinical inflammatory conditions like metabolic syndrome, T2DM, CVDs, polycystic ovary syndrome (PCOS), etc.

Serum Fetuin-A Levels in Patients with Bilateral Basal Ganglia Calcification

BACKGROUND AND PURPOSE

The idiopathic basal ganglia calcification (Fahr syndrome) may occur due to senility. Fetuin-A is a negative acute phase reactant which inhibits calcium-phosphorus precipitation and vascular calcification. In this study, we aimed to evaluate whether serum fetuin-A levels correlate with bilateral basal ganglia calcification.

METHOD

Forty-five patients who had bilateral basal ganglia calcification on brain CT were selected according to the inclusion and exclusion criteria, and 45 age and gender-matched subjects without basal ganglia calcification were included for the control group. Serum fetuin-A levels were measured from venous blood samples. All participants were divided into two groups; with and without basal ganglia calcification. These groups were divided into subgroups regarding age (18-32 and 33-45 years of age) and gender (male, female).

RESULTS

We detected lower levels of serum fetuin-A in patients with basal ganglia calcification compared with the subjects without basal ganglia calcification. In all subgroups (female, male, 18-32 years and 33-45 years), mean fetuin-A levels were significantly lower in patients with basal ganglia calcification (p = 0.017, p = 0.014, p = 0.024, p = 0.026, p = 0.01 respectively). And statistically significantly lower levels of fetuin-A was found to be correlated with the increasing densities of calcification in the calcified basal ganglia group (p-value: <0.001).

CONCLUSION

Considering the role of fetuin-A in tissue calcification and inflammation, higher serum fetuin-A levels should be measured in patients with basal ganglia calcification. We believe that the measurement of serum fetuin-A may play a role in the prediction of basal ganglia calcification as a biomarker.

Plasma proteomics reveals coagulation, inflammation, and metabolic shifts in H-type hypertension patients with and without acute ischemic stroke

Systematic profiling of a larger portion of circulating plasma proteome provide opportunities for unbiased discovery of novel markers to improve diagnostic, therapeutic, or predictive accuracy. This study aimed to identify differentially expressed proteins (DEPs) in plasma that could provide overall insight into the molecular changes of both H- type hypertension (HH) and HH-related acute ischemic stroke (AIS). This study used an iTRAQ-based LC-MS/MS proteomics approach to screen for plasma DEPs in HH patients with and without AIS, and controls. After excluding highly abundant plasma proteins, more than 600 proteins, and their relative levels, were identified. Of these, 26 DEPs, each showing > 1.2-fold change, were identified in HH and HH-related AIS patients compared with controls. Bioinformatics analysis revealed that these DEPs were enriched in 21 functional gene ontology items; “blood coagulation” was the most predominant pathway showing enrichment. Of these, eight DEPs were located in the hub position of networks involved with protein-protein interactions. AT-3, CRP, ApoB, and AHSG were further validated in each group by enzyme-linked immune sorbent assays. Comparing HH-related AIS with HH, the areas under the curve for AT-3, CRP, ApoB, and AHSG were 0.698, 0.892, 0.626, and 0.847, respectively. This proteomic profiling study provided enhanced pathophysiological understanding of the regulatory processes involved in coagulation, inflammation, and metabolism, and identified a panel of novel biomarkers for detecting HH-related AIS during its pre-stroke stage.

Serum fetuin-A levels and abdominal aortic calcification in healthy men - The STRAMBO study

Vascular calcification results from an imbalance between increased extracellular levels of calcium and phosphate, reduced solubility, and low levels of calcification inhibitors in blood or the vascular wall. Fetuin-A is a major circulating calcification inhibitor. Rodent models of fetuin-A deficit indicate its calcification inhibiting potential. Clinical studies suggest its role as a biomarker in vascular disease. This cross-sectional study was performed in a cohort of 974 men aged ≥ 40 years (average 68 years) consisting of men holding health insurance cover with Mutuelle des Travailleurs de la Région Lyonnaise. Abdominal aortic calcification (AAC) was assessed semi-quantitatively on lateral dual energy X-ray absorptiometry (DXA) spine scans. Serum fetuin-A was measured by an immunoassay. After adjustment for confounders (age, lifestyle, body composition, health status, treatment, glomerular filtration rate [GFR], hormones, and cytokines), prevalence of severe AAC (AAC score>4) decreased with increasing fetuin-A levels (OR=0.68 per SD increase, 95% CI: 0.54-0.84, p<0.001). After adjustment for confounders, low fetuin-A and hypertension were each associated with higher odds of AAC>4. Coexistence of low serum fetuin-A levels and heavy smoking, elevated fibroblast growth factor 23 levels or low serum dickkopf-1 levels were associated with higher odds of AAC>4. Similar results were obtained for 789 men with GFR>60 mL/min/1.73 m(2). Similar results were obtained when severe AAC was defined as AAC score >3 or AAC>5. Thus, lower serum fetuin-A levels are associated with severe AAC, suggesting that poor calcification inhibitory potential contributes to vascular calcification, independently of renal impairment.

Plasma levels of fetuin-A and risk of coronary heart disease in US women: the Nurses' Health Study

BACKGROUND

Fetuin-A may be involved in the etiology of coronary heart disease (CHD) through opposing pathways (ie, promoting insulin resistance and inhibiting ectopic calcification). We aimed to explicitly examine whether systemic inflammation, a factor leading to elevated vascular calcification, may modify the association between fetuin-A and CHD risk.

METHOD AND RESULTS

During 16 years of follow-up (1990-2006), we prospectively identified and confirmed 466 incident fatal or nonfatal CHD case in the Nurses' Health Study. For each case, 1 healthy control was selected using risk-set sampling from 26 245 eligible participants. Cases and controls were matched for age, smoking status, fasting status, and date of blood draw. After multivariate adjustment for lifestyle factors, body mass index, diet, and blood lipids, fetuin-A levels were not associated with CHD risk in the whole population: odds ratio (OR) (95% CI) comparing extreme quintiles of fetuin-A was 0.79 (0.44 to 1.40). However, a significant inverse association was observed among participants with higher C-reactive protein levels (Pinteraction=0.04). The OR (95% CI) comparing highest versus lowest quintiles of fetuin-A was 0.50 (0.26 to 0.97; Ptrend=0.004) when C-reactive protein levels were above population median (0.20 mg/dL), whereas among the remainder of the participants, the corresponding OR (95% CI) was 1.09 (0.58 to 2.05; Ptrend=0.75).

CONCLUSIONS

In this population of US women, fetuin-A levels were associated with lower CHD risk when C-reactive protein levels were high, but null association was observed among participants with lower C-reactive protein levels. This divergent pattern of association needs replication in future studies.