Exercise improves lipid metabolism disorders induced by high-fat diet in a SESN2/JNK-independent manner

SESN2 and JNK are emerging powerful stress-inducible proteins in regulating lipid metabolism. The aim of this study was to determine the underlying mechanism of SESN2/JNK signaling in exercise to improve lipid disorder induced by high-fat diet (HFD). Our data showed that HFD and SESN2 knockout resulted in abnormalities including elevated body weight, increased fat mass, serum total cholesterol, lipid biosynthesis related proteins, and a concomitant increase of pJNK-Thr183/Tyr185. The above changes were reversed by exercise training. SESN2 silencing or JNK inhibition in palmitate-treated C2C12 further confirmed that SESN2 and JNK play a vital role in lipid biosynthesis. Rescue experiment further demonstrated that SESN2 reduced lipid biosynthesis through inhibition of JNK. SESN2/JNK signaling axis regulates lipid biosynthesis in both animal and cell models with abnormalities of lipid metabolism induced by HFD or palmitate treatment. This study provided evidence that exercise ameliorated lipid metabolic disorder induced by HFD feeding or by SESN2 knockout. SESN2 may improve lipid metabolism through inhibition JNK expression in skeletal muscle cells, providing a molecular mechanism that may represent an attractive target for the treatment of lipid disorder. Novelty: Exercise improved lipid disorder induced by HFD feeding and SESN2 knockout. SESN2 and JNK play a vital role in lipid biosynthesis in vivo and in vitro. SESN2 suppressed JNK to improve lipid metabolism in skeletal muscle cells.

Ovariectomy-Induced Hepatic Lipid and Cytochrome P450 Dysmetabolism Precedes Serum Dyslipidemia

Ovarian hormone deficiency leads to increased body weight, visceral adiposity, fatty liver and disorders associated with menopausal metabolic syndrome. To better understand the underlying mechanisms of these disorders in their early phases of development, we investigated the effect of ovariectomy on lipid and glucose metabolism. Compared to sham-operated controls, ovariectomized Wistar female rats markedly increased whole body and visceral adipose tissue weight (p ˂ 0.05) and exhibited insulin resistance in peripheral tissues. Severe hepatic triglyceride accumulation (p ˂ 0.001) after ovariectomy preceded changes in both serum lipids and glucose intolerance, reflecting alterations in some CYP proteins. Increased CYP2E1 (p ˂ 0.05) and decreased CYP4A (p ˂ 0.001) after ovariectomy reduced fatty acid oxidation and induced hepatic steatosis. Decreased triglyceride metabolism and secretion from the liver contributed to hepatic triglyceride accumulation in response to ovariectomy. In addition, interscapular brown adipose tissue of ovariectomized rats exhibited decreased fatty acid oxidation (p ˂ 0.01), lipogenesis (p ˂ 0.05) and lipolysis (p ˂ 0.05) despite an increase in tissue weight. The results provide evidence that impaired hepatic triglycerides and dysregulation of some CYP450 proteins may have been involved in the development of hepatic steatosis. The low metabolic activity of brown adipose tissue may have contributed to visceral adiposity as well as triglyceride accumulation during the postmenopausal period.

Pediatric Lipid Disorders

Current scientific evidence has proven that atherosclerosis is a process that begins in childhood and tracks into adulthood, likely culminating in adverse cardiovascular events such as coronary artery disease, peripheral artery disease, and stroke. In addition, the obesity epidemic and increasing awareness of genetic lipid disorders has made the understanding and management of lipid disorders necessary for pediatricians. Childhood offers a unique opportunity for preventing, modifying, or eliminating risk factors and, in doing so, reversing or slowing the process of atherosclerosis. In general, management involves targeted lifestyle interventions such as strict dietary changes and increases in physical activity. In some circumstances, pharmacotherapy, even in childhood, is warranted. [Pediatr Ann. 2021;50(3):e105-e112.].

The Causal Effects of Blood Iron and Copper on Lipid Metabolism Diseases: Evidence from Phenome-Wide Mendelian Randomization Study

Blood levels of iron and copper, even within their normal ranges, have been associated with a wide range of clinical outcomes. The available epidemiological evidence for these associations is often inconsistent and suffers from confounding and reverse causation. This study aims to examine the causal clinical effects of blood iron and copper with Mendelian randomization (MR) analyses. Genetic instruments for the blood levels of iron and copper were curated from existing genome-wide association studies. Candidate clinical outcomes were identified based on a phenome-wide association study (PheWAS) between these genetic instruments and a wide range of phenotypes in 310,999 unrelated individuals of European ancestry from the UK Biobank. All signals passing stringent correction for multiple testing were followed by MR analyses, with replication in independent data sources where possible. We found that genetically predicted higher blood levels of iron and copper are both associated with lower risks of iron deficiency anemia (odds ratio (OR) = 0.75, 95% confidence interval (CI): 0.67-0.85, p = 1.90 × 10-6 for iron; OR = 0.88, 95% CI: 0.78-0.98, p = 0.032 for copper), lipid metabolism disorders, and its two subcategories, hyperlipidemia (OR = 0.90, 95% CI: 0.85-0.96, p = 6.44 × 10-4; OR = 0.92, 95% CI: 0.87-0.98, p = 5.51 × 10-3) and hypercholesterolemia (OR = 0.90, 95% CI: 0.84-0.95, p = 5.34 × 10-4; OR = 0.93, 95% CI: 0.89-0.99, p = 0.022). Consistently, they are also associated with lower blood levels of total cholesterol and low-density lipoprotein cholesterol. Multiple sensitivity tests were applied to assess the presence of pleiotropy and the robustness of causal estimates. Regardless of the approaches, consistent evidence was obtained. Moreover, the unique clinical effects of each blood mineral were identified. Notably, genetically predicated higher blood iron is associated with an enhanced risk of varicose veins (OR = 1.28, 95% CI: 1.15-1.42, p = 4.34 × 10-6), while blood copper is positively associated with the risk of osteoarthrosis (OR = 1.07, 95% CI: 1.02-1.13, p = 0.010). Sex-stratified MR analysis further revealed some degree of sex differences in their clinical effects. Our comparative PheWAS-MR study of iron and copper comprehensively characterized their shared and unique clinical effects, highlighting their potential causal roles in hyperlipidemia and hypercholesterolemia. Given the modifiable nature of blood mineral status and the potential for clinical intervention, these findings warrant further investigation.

HDL Cholesterol Efflux Capacity is Impaired in Severe Short-Term Hypothyroidism Despite Increased HDL Cholesterol

CONTEXT

Severe hypothyroidism has profound effects on lipoprotein metabolism including high-density lipoprotein (HDL) cholesterol elevations but effects on HDL function metrics are unknown.

OBJECTIVE

To determine the impact of severe short-term hypothyroidism on HDL particle characteristics, HDL cholesterol efflux capacity (CEC), and HDL antioxidative capacity.

DESIGN

Observational study with variables measured during severe short-term hypothyroidism (median TSH 81 mU/L) and after 20 weeks of thyroid hormone supplementation (median TSH 0.03 mU/L) (Netherlands Trial Registry ID 7228).

SETTING

University hospital setting in The Netherlands.

PATIENTS

Seventeen patients who had undergone a total thyroidectomy for differentiated thyroid carcinoma.

MAIN OUTCOME MEASURES

HDL particle characteristics (nuclear magnetic resonance spectrometry), CEC (human THP-1-derived macrophage foam cells and apolipoprotein B-depleted plasma), and HDL anti-oxidative capacity (inhibition of low-density lipoprotein oxidation).

RESULTS

During hypothyroidism plasma total cholesterol, HDL cholesterol and apolipoprotein A-I were increased (P ≤ 0.001). HDL particle concentration was unchanged, but there was a shift in HDL subclasses toward larger HDL particles (P < 0.001). CEC was decreased (P = 0.035), also when corrected for HDL cholesterol (P < 0.001) or HDL particle concentration (P = 0.011). HDL antioxidative capacity did not change.

CONCLUSION

During severe short-term hypothyroidism CEC, an important antiatherogenic metric of HDL function, is impaired. HDL cholesterol and larger HDL particles are increased but HDL particle concentration is unchanged. Combined, these findings suggest that HDL quality and quantity are not improved, reflecting dysfunctional HDL in hypothyroidism.

NLRP3 Inflammasome in Inflammation and Metabolism: Identifying Novel Roles in Postburn Adipose Dysfunction

Inflammasomes are multiprotein complexes that respond to pathogen or host associated damage markers, leading to caspase-1 maturation and processing of pro-inflammatory cytokines. Initially, inflammasomes were implicated primarily in inflammatory and infectious conditions. However, increasing evidence demonstrates broader roles beyond inflammation, including regulation of adipose tissue metabolism after burns. Here, we conducted a search for articles on PubMed, Web of Science, Embase, Scopus, and UpToDate with applied search strategies including a combination of "burns," "trauma," "(NLRP3) inflammasome," "metabolic conditions," "white adipose tissue," "macrophages," "browning," and "lipolysis" and included papers from 2000 to 2020. We discuss unexpected roles for NLRP3, the most characterized inflammasome to date, as a key metabolic driver in a variety of conditions. In particular, we highlight the function of NLRP3 inflammasome in burn trauma, which is characterized by both hyperinflammation and hypermetabolism. We identify a critical part for NLRP3 activation in macrophage dynamics and delineate a novel role in postburn white adipose tissue remodeling, a pathological response associated with hypermetabolism and poor clinical outcomes. Mechanistically, how inflammation and inflammasome activation is linked to postburn hypermetabolism is a novel concept to contemplate, and herein we provide evidence of an immunometabolic crosstalk between adipocytes and infiltrating macrophages.

Gestational hypothyroidism elicits more pronounced lipid dysregulation in mice than pre-pregnant hypothyroidism

Thyroid hormone is crucial for regulating lipid and glucose metabolism, which plays essential role in maintaining the health of pregnant women and their offspring. However, the current literature is just focusing on the development of offspring born to the untreated mothers with hypothyroidism, rather than mothers themselves. Additionally, the interaction between hypothyroidism and pregnancy, and its impact on the women's health are still elusive. Therefore, this study was designed to compare the metabolic differences in dams with hypothyroidism starting before pregnancy and after pregnancy. Pre-pregnant hypothyroidism was generated in 5-week-old female C57/BL/6J mice using iodine-deficient diet containing 0.15% propylthiouracil for 4 weeks, and the hypothyroidism was maintained until delivery. Gestational hypothyroidism was induced in dams after mating, using the same diet intervention until delivery. Compared with normal control, gestational hypothyroidism exhibited more prominent increase than pre-pregnant hypothyroidism in plasma total cholesterol and low-density lipoprotein cholesterol, and caused hepatic triglycerides accumulation. Similarly, more significant elevations of protein expressions of SREBP1c and p-ACL, while more dramatic inhibition of CPT1A and LDL-R levels were also observed in murine livers with gestational hypothyroidism than those with pre-pregnant hypothyroidism. Moreover, the murine hepatic levels of total cholesterol and gluconeogenesis were dramatically and equally enhanced in two hypothyroid groups, while plasma triglycerides and protein expressions of p-AKT, p-FoxO1 and APOC3 were reduced substantially in two hypothyroid groups. Taken together, our current study illuminated that gestational hypothyroidism may elicit more pronounced lipid dysregulation in dams than dose the pre-pregnant hypothyroidism.

Crosstalk Between Lipids and Mitochondria in Diabetic Kidney Disease

PURPOSE OF REVIEW

The goal of this review is to review the role that renal parenchymal lipid accumulation plays in contributing to diabetic kidney disease (DKD), specifically contributing to the mitochondrial dysfunction observed in glomerular renal cells in the context of DKD development and progression.

RECENT FINDINGS

Mitochondrial dysfunction has been observed in experimental and clinical DKD. Recently, Ayanga et al. demonstrate that podocyte-specific deletion of a protein involved in mitochondrial dynamics protects from DKD progression. Furthermore, our group has recently shown that ATP-binding cassette A1 (a protein involved in cholesterol and phospholipid efflux) is significantly reduced in clinical and experimental DKD and that genetic or pharmacological induction of ABCA1 is sufficient to protect from DKD. ABCA1 deficiency in podocytes leads to mitochondrial dysfunction observed with alterations of mitochondrial lipids, in particular, cardiolipin (a mitochondrial-specific phospholipid). However, through pharmacological reduction of cardiolipin peroxidation DKD progression is reverted. Lipid metabolism is significantly altered in the diabetic kidney and renders cellular components, such as the podocyte, susceptible to injury leading to worsened DKD progression. Dysfunction of the lipid metabolism pathway can also lead to mitochondrial dysfunction and mitochondrial lipid alteration. Future research aimed at targeting mitochondrial lipids content and function could prove to be beneficial for the treatment of DKD.

Short-term high-fat diet exacerbates insulin resistance and glycolipid metabolism disorders in young obese men with hyperlipidemia, as determined by metabolomics analysis using ultra-HPLC-quadrupole time-of-flight mass spectrometry

BACKGROUND

The prevalence of obesity is increasing rapidly worldwide, and dietary intake is strongly associated with obesity-related chronic diseases. However, key metabolic perturbations in obese young men with hyperlipidemia after high-fat diet (HFD) intervention are not yet clear, and remain to be determined. The aim of this study was to investigate the effects of a short-term HFD on glycolipid metabolism, insulin resistance (IR), and urinary metabolomic profiling in young obese men with hyperlipidemia.

METHODS

Sixty young men (19-25 years; 30 normal weight, 30 obese with hyperlipidemia) were enrolled in the study. Differences in metabolomic profiling of urine between normal-weight and obese young men before and after 3 days intake of the HFD were investigated using ultra-HPLC-quadrupole time-of-flight mass spectrometry.

RESULTS

After the HFD intervention, total cholesterol (TC), low-density lipoprotein cholesterol, fasting plasma glucose, insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) were significantly increased and high-density lipoprotein cholesterol was significantly decreased in obese men, but only TC was significantly increased in normal-weight subjects. Based on metabolic differences, normal-weight and obese men, and obese men before and after the HFD intervention could be separated into distinct clusters. Seventeen major metabolites were identified that were associated with type 2 diabetes mellitus, glycolipid metabolism and IR; the changes in these metabolites suggest metabolic changes in young obese males after short-term HFD intake.

CONCLUSIONS

The findings of this study may contribute to increased understanding of the early biological adaptations of obesity with hyperlipidemia to HFD for the early prevention and control of diabetes and IR.

Pathogenesis of Lipid Disorders in Insulin Resistance: a Brief Review

PURPOSE OF REVIEW

Insulin resistance (IR) is recognized to play an important role in the pathogenesis of dyslipidemia. This review summarizes the complex interplay between IR and dyslipidemia in people with and without diabetes.

RECENT FINDINGS

IR impacts the metabolism of triglycerides, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and very low-density lipoprotein cholesterol (VLDL-C) by several mechanisms. Trials with insulin sensitizing therapies, including biguanides and thiazolidinediones, have provided inconsistent results on lipid lowering in people with and without diabetes. In this review, we focus on the pathophysiological interplay between IR and dyslipidemia and recapitulate lipid and lipoprotein data from insulin-sensitizing trials. Further research elucidating the reciprocal relationship between IR and dyslipidemia is needed to better target these important risk factors for cardiovascular disease.

[Lipid metabolism abnormalities in Chronic Kidney Disease]

Regardless of the etiology of renal disease, patients with chronic kidney disease (CKD) develop profound qualitative and quantitative lipoprotein metabolism abnormalities because of the presence of alterations in apolipoproteins, lipid transfer proteins, lipolytic enzymes, and lipoprotein receptors from the earlier stages of the disease. As renal function deteriorates, triglyceride concentrations increase and high-density lipoprotein cholesterol (HDL) concentrations decline, while levels of low- density lipoprotein (LDL) cholesterol remain in the normal range or become slightly decreased. Meanwhile, there is a progressive accumulation of the more atherogenic small dense LDL particles. In stages 4 and 5 of CKD, there is decreased concentration of apolipoprotein A-containing lipoproteins, and increased concentrations of triglyceride-rich apolipoprotein B-containing lipoproteins. Patients with nephrotic syndrome and preserved glomerular filtration rate show a higher atherogenic profile, with markedly elevated plasma cholesterol, triglyceride concentrations, and increased very low (VLDL) and low density lipoprotein (LDL), intermediate density lipoprotein (IDL) and lipoprotein(a) levels. Depressed plasma HDL cholesterol concentrations are also commonly observed in patients with nephrotic syndrome. Unless nephrotic syndrome is present, lipid abnormalities are not commonly observed when the lipid profile is measured using standard quantitative methods. In particular, total and LDL cholesterol, the most common lipid parameters used to stratify the cardiovascular risk and assess the effect of treatment with statins, are usually normal and often low. However, there is evidence that some alterations of the qualitative profile of lipoprotein are characteristic of chronic kidney disease, and probably contribute to the high rate of atherosclerotic events observed in these patients. These qualitative abnormalities include increased levels of VLDL and IDL cholesterol, small dense and oxidized LDL particles and lipoprotein(a). Moreover, HDL cholesterol is usually low and dysfunctional, not acting as protective, but paradoxically as proatherogenic particles. The lipid profile of CKD shows similar features to the metabolic syndrome and type 2 diabetes, conditions well known to predispose to kidney disease, which in turn aggravates insulin resistance and promotes atherogenic dyslipidemia.

Clinical dilemmas in the management of transgender men

PURPOSE OF REVIEW

To explore the medical and surgical clinical dilemmas in the management of trans (transgender) men, a growing population receiving more attention than in the past.

RECENT FINDINGS

Testosterone therapy is commonly prescribed to trans men for masculinization. Nonetheless, the optimal formulations and doses of testosterone therapy for trans men have not been well established. Testosterone therapy has been associated with increased levels of hemoglobin and triglycerides, as well as diabetes. Periodic monitoring of hemoglobin, cholesterol, and fasting glucose is therefore recommended. As compared to non-transgender women, trans men have lower age-specific rates of breast cancer and cervical cancer which can be attributed, in part, to surgeries such as bilateral mastectomies and hysterectomies. The frequency in which to recommend mammograms and Pap smears (in patients with intact cervices) is uncertain in this population because of a lack of evidence-based data. Many trans men desire and undergo bilateral mastectomies with much fewer undergoing metoidioplasty or phalloplasty.

SUMMARY

For trans men, most clinicians target serum testosterone concentrations in the normal male reference range. The frequency of screening for breast and cervical cancer should be individualized based upon anatomy, patient age, age of initiation of testosterone therapy, and other factors.

Risk factors of lipid metabolism disorders in residents of multi-environmental exposure to cadmium and arsenic

The authors evaluated negative effects of cadmium and arsenic compounds on health of population residing near storage of extraction and processing waste of ore mining and processing enterprise. Hygienic analysis covered quality of ambient air, drinkable water and foods, evaluation of risk factors of lipid metabolism disorders. Clinical and laboratory examination involved 137 children and 99 adults in chronic multi-environmental (ambient air, water, foods) exposure to metals (cadmium and arsenic, HI 1.21-1.29), diagnosed endocrine diseases including lipid metabolism disorders (excessive nutrition and obesity, E67.8-66.0) in adults 1.4 times more, and in children in 1.7-2.2 times more than in the reference group. Direct probable statistically significant cause-effect relationship was established between lipid metabolism disorders and serum levels of cadmium and arsenic (R² = 0,36-0,95; 71,07≤ F ≤2597,94; p< 0,001). In multi-environmental exposure to cadmium and arsenic, reduced index of lipid metabolic disorders risk in adult population exceeds upper limit of low risk level (0,05) at 33 years of age, of high risk level (0,35) - at 58 years of age and very high (0,6) - at 63 years of age.

Loss of CD24 in Mice Leads to Metabolic Dysfunctions and a Reduction in White Adipocyte Tissue

CD24 is a glycophosphatidylinositol (GPI)-linked cell surface receptor that is involved in regulating the survival or differentiation of several different cell types. CD24 has been used to identify pre-adipocytes that are able to reconstitute white adipose tissue (WAT) in vivo. Moreover, we recently found that the dynamic upregulation of CD24 in vitro during early phases of adipogenesis is necessary for mature adipocyte development. To determine the role of CD24 in adipocyte development in vivo, we evaluated the development of the inguinal and interscapular subcutaneous WAT and the epididymal visceral WAT in mice with a homozygous deletion of CD24 (CD24KO). We observed a significant decrease in WAT mass of 40% to 74% in WAT mass from both visceral and subcutaneous depots in male mice, with no significant effect in female mice, compared to wild-type (WT) sex- and age-matched controls. We also found that CD24KO mice had increased fasting glucose and free fatty acids, decreased fasting insulin, and plasma leptin. No major differences were observed in the sensitivity to insulin or glucose, or in circulating triglycerides, total cholesterol, HDL-cholesterol, or LDL-cholesterol levels between WT and CD24KO mice. Challenging the CD24KO mice with either high sucrose (35%) or high fat (45%) diets that promote increased adiposity, increased WAT mass and fasting insulin, adiponectin and leptin levels, as well as reduced the sensitivity to insulin and glucose, to the levels of WT mice on the same diets. The CD24-mediated reduction in fat pad size was due to a reduction in adipocyte cell size in all depots with no significant reduction pre-adipocyte or adipocyte cell number. Thus, we have clearly demonstrated that the global absence of CD24 affects adipocyte cell size in vivo in a sex- and diet-dependent manner, as well as causing metabolic disturbances in glucose homeostasis and free fatty acid levels.

[Roles of lipoprotein and apolipoprotein in HCV infection]

Although chronic infection of hepatitis C virus (HCV) induces disorders of lipid metabolism, HCV is known to utilize lipid metabolism for efficient propagation in the liver. Due to the morphological and physiological similarities of HCV particles to lipoproteins, lipid-associated HCV particles are named lipoviroparticles. Previous reports have shown that lipoprotein receptors or cholesterol transporter participate in the entry of lipoviroparticles. In addition, recent analyses revealed that exchangeable apolipoproteins directly interact with the viral membrane to generate infectious HCV particles. In this review, we would like to discuss about involvement of lipoprotein and apolipoprotein in HCV lifecycle.

Lymphocytes as liver damage mirror of HCV related adipogenesis deregulation

Hepatitis C virus infection leads to a wide spectrum of liver diseases ranging from mild chronic hepatitis to end-stage cirrhosis and hepatocellular carcinoma. An intriguing aspect of the HCV infection is its close connection with lipid metabolism playing an important role in the HCV life cycle and in its pathogenesis. HCV is known to be a hepatotropic virus; however, it can also infect peripheral blood mononuclear cells (PBMCs). The goal of the current investigation is to compare the adipogenesis profile of liver tissues to lymphocytes of HCV infected patients, in order to understand if PBMCs may reflect the alterations of intracellular pathways occurring during HCV-related liver steatosis. Using the Human Adipogenesis PCR Array, gene expression was analyzed in liver samples and PBMCs of chronic HCV+, HBV+ and Healthy Donors (HDs) patients. We observed a similar modulation of lipid metabolism in HCV+ and HBV+liver tissues and lymphoid, cells suggesting that PBMCs reflect the liver adipogenesis deregulation related to infection, even if the two viruses have a different impact in the regulation of the adipogenesis mechanisms. In particular, some genes involved in lipid metabolism and inflammation, as well as in cell transformation, were up-regulated, in a similar way, in both HCV models analyzed. Interestingly, these genes were positively correlated to virological and hepatic functional parameters of HCV+ patients. On the contrary, HBV+ patients displayed a completely different profile. PBMCs of HCV+ patients seem to be useful model to study how HCV-related lipid metabolism deregulation occurs in liver. The obtained data suggest some molecules as new possible biomarkers of HCV-related liver damage progression.

Neonatal overnutrition in mice exacerbates high-fat diet-induced metabolic perturbations

Neonatal overnutrition results in accelerated development of high-fat diet (HFD)-induced metabolic defects in adulthood. To understand whether the increased susceptibility was associated with aggravated inflammation and dysregulated lipid metabolism, we studied metabolic changes and insulin signaling in a chronic postnatal overnutrition (CPO) mouse model. Male Swiss Webster pups were raised with either three pups per litter to induce CPO or ten pups per litter as control (CTR) and weaned to either low-fat diet (LFD) or HFD. All animals were killed on the postnatal day 150 (P150) except for a subset of mice killed on P15 for the measurement of stomach weight and milk composition. CPO mice exhibited accelerated body weight gain and increased body fat mass prior to weaning and the difference persisted into adulthood under conditions of both LFD and HFD. As adults, insulin signaling was more severely impaired in epididymal white adipose tissue (WAT) from HFD-fed CPO (CPO-HFD) mice. In addition, HFD-induced upregulation of pro-inflammatory cytokines was exaggerated in CPO-HFD mice. Consistent with greater inflammation, CPO-HFD mice showed more severe macrophage infiltration than HFD-fed CTR (CTR-HFD) mice. Furthermore, when compared with CTR-HFD mice, CPO-HFD mice exhibited reduced levels of several lipogenic enzymes in WAT and excess intramyocellular lipid accumulation. These data indicate that neonatal overnutrition accelerates the development of insulin resistance and exacerbates HFD-induced metabolic defects, possibly by worsening HFD-induced inflammatory response and impaired lipid metabolism.

[Long-term effects of mild hyperglycemia exposure in utero and postnatal high fat diet on body weight and lipid metabolism in rat offsprings]

OBJECTIVE

To investigate the long-term effects of intrauterine mild hyperglycemia exposure and postnatal high fat diet on the body weight and metabolism of offspring through a pregnant rat model of intrauterine mild hyperglycemia.

METHODS

Twenty-one pregnant Wistar rats were randomly divided into intrauterine hyperglycemia group and control group. Twenty percent streptozotocin (STZ, 25 mg/kg)was given to rats of intrauterine hyperglycemia group by a single intraperitoneal injection to induce intrauterine mild hyperglycemia; control group rats received an equal volume of citric acid-sodium citrate buffer. Off springs were divided into 4 groups: exposed to intrauterine hyperglycemia and fed with normal diet group (group DN) or high fat diet group (group DF); exposed to intrauterine euglycemia and fed with normal diet group (group CN) or high fat diet group (group CF). The blood glucose levels of pregnant rats in two groups and body weights of offsprings in four groups were recorded. At the age of 28 weeks, the mesenteric fat amount, epididymal amount, perirenal fat amount, total triglyceride (TG) and high density 1ipoprotein-cholestrol (HDL-C) were measured in all four groups.

RESULTS

(1)The average blood glucose level of intrauterine hyperglycemia group [(16.6 ± 3.4) mmol/L] was significantly higher than that of the control group [(5.8 ± 1.1) mmol/L, P < 0.01]. (2) On the birth day, 3 weeks and 4 weeks, the body weight of group DN[(7.4 ± 0.6), (44.1 ± 5.9), (79.6 ± 7.4) g] and group DF [(7.4 ± 0.2), (43.9 ± 6.9), (76.1 ± 5.8) g] were remarkably increased compared with group CN [(6.6 ± 0.5),(35.6 ± 4.4),(71.5 ± 6.8) g, P < 0.05]; but the body weight in group CF [(6.7 ± 0.5),(33.0 ± 6.5),(66.1 ± 10.2) g] had no statistical difference compared with group CN (P > 0.05). (3)From then on, the body weights of the offsprings in four groups presented an increasing trend, but there was no statistical difference until 28 weeks (P > 0.05). (4) The perirenal fat amount of group DN, group CF and group DF [(13.8 ± 3.3), (14.3 ± 3.2), (18.4 ± 1.3) g] were remarkably increased compared with group CN[(9.7 ± 3.5) g, P < 0.05]; the epididymal fat amount of group CF and group DF were also significantly increased compared to group CN (P < 0.05); the mesenteric fat amount in four groups had no statistical difference (P > 0.05). (5) The TG level of group DN, group CF and group DF [(0.52 ± 0.14), (0.52 ± 0.09), (0.54 ± 0.17) mmol/L] were significantly higher compared to group CN [(0.41 ± 0.09) mmol/L, P < 0.05], but there was no statistical difference within the first three groups (P > 0.05); the HDL-C level in four groups had no statistical difference (P > 0.05).

CONCLUSIONS

In intrauterine mild hyperglycemia environment, there were some evidently metabolic changes observed in the offspring, including body weight increasing on birth day and early postnatal period, visceral fat amount increasing and lipid metabolism disorders, which could be aggravated by postnatal high fat diet.

Unfavorable lipid profile and higher frequency of hot flashes during perimenopausal years after fallopian tube ligation

AIM

We sought to study the effect of tubal ligation on lipid profile, ovarian reserve and hot flashes during perimenopausal years.

METHODS

A total of 210 perimenopausal women complaining of abnormal vaginal bleeding were enrolled for the study. Subjects' menstrual, reproductive and medical histories were recorded. Serum FSH, LH and estradiol levels were screened in all women to determine menopausal status. In order to rule out any gynecologic pathology, all subjects underwent transvaginal sonography. Women were divided into two groups according to presence (study group, n = 68) or absence (control group, n = 142) of tubal ligation history. Lipid profiles and ovarian reserve tests were compared between groups.

RESULTS

Mean age, parity, serum hemoglobin (Hb), high density lipoprotein (HDL-C), triglyceride, estradiol levels, endometrial thickness and frequency of hot flashes were significantly different between groups (p < 0.05). Mean age was 42.8 ± 1.9 years in women with tubal ligation and 45.9 ± 3.5 years in control group. Mean serum estradiol level was lower in group with tubal ligation (41.4 versus 92.5 pg/ml). Mean endometrial thickness was higher in control group (10.2 versus 7.5 mm). Age-adjusted serum Hb, HDL-C, triglyceride, estradiol, FSH level, endometrial thickness and frequency of hot flashes remained significantly different between groups (p < 0.05).

CONCLUSION

Tubal ligation is associated with unfavorable lipid profile and higher frequency of hot flashes during perimenopausal years.

[Age-related aspects of the extent of lipid metabolism and post-traumatic stress disorders among veterans of modern warfare]

The peculiarities of violations of lipid metabolism and symptoms of post-traumatic stress disorder (PTSD) in 161 patients of 25-69 years, veterans of the military actions on the territory of Afghanistan and the Northern Caucasus were investigated. The dependence of the formation of dyslipidemia and related changes of atherosclerosis in the young age on neuroendocrine effects, accompanying the effects of combat stress and promoting accelerated aging was determined. On the other hand, with the time, after 15-25 years after participating in hostilities, the intensity of PTSD and its influence on the development of violations of lipid spectrum may decline. The leading role in the pathogenesis of dyslipidemia goes to age-related changes, accompanying a process of accelerated aging of veterans of combat operations, and to pathological disorders of metabolism in liver associated with alcohol abuse and the consequences of infectious diseases.

[Water and electrolyte metabolism disturbances in patients with metabolic syndrome]

Taking into account the high prevalence of renal disease in metabolic syndrome (MS), relationship between the reduction of the renal function and severity of disorders of lipid metabolism and increased risk of cardiovascular complications, evaluation of electrolyte and nitrogen metabolism was performed for 112 patients with MS. In addition, serum levels ofaldosterone, adrenocorticotropic hormone, neutrophil gelatinase-associated lipocalin, cortisol, beta2-microglobulin, vasopressin, and level of microalbumin in urine were assessed. MS patients showed a reduction of the daily expression of the main osmotically active substance - urea, potassium, sodium and chloride. The increased production of antidiuretic hormone and related water retention, increased microalbumin excretion, indicating the development of systemic endothelial dysfunction and glomerular hyperfiltration, were detected. Reported violations are developing by type of "vicious circle": fluid retention leads to hyperfiltration, renal dysfunction exacerbates water-electrolyte disorders.

Lipid insudation as a cause of structural failure of a stentless pericardial bioprosthesis

The Sorin Pericarbon Freedom (SPF) valve is a stentless bioprosthesis made from bovine pericardium, with a peculiar design aimed at preventing the mechanical failures observed with old models of stented pericardial bioprostheses. Herein, the case is described of a patient who presented with severe regurgitation of a SPF six years after aortic valve replacement, caused by commissural dehiscence. Both, microradiographic and histologic investigations, revealed mild calcific deposits and massive lipid infiltration, thus confirming that a patient-related mechanism such as 'atheromasia' can account for structural valve deterioration also in recipients of pericardial bioprostheses.

Update in lipid alterations in subclinical hypothyroidism

Thyroid hormone has multiple effects on the regulation of lipid synthesis, absorption, and metabolism. Studies consistently demonstrate elevated levels of serum total cholesterol, low-density lipoprotein cholesterol (LDL-C), apolipoprotein B, lipoprotein(a), and possibly triglycerides in individuals with overt hypothyroidism, all of which are reversible with levothyroxine therapy. Although it is estimated that 1 to 11% of all patients with dyslipidemia have subclinical hypothyroidism, the effects of subclinical hypothyroidism on serum lipid values are less clear. Apolipoprotein B levels may be increased in patients with subclinical hypothyroidism. Although some studies have demonstrated that total cholesterol and LDL-C levels are elevated in patients with subclinical hypothyroidism, others have not shown any effect of subclinical hypothyroidism on these lipid measurements. Serum triglycerides, lipid subparticle size, and LDL-C oxidizability may be altered in subclinical hypothyroidism, but these studies have also been inconsistent. The preponderance of evidence suggests that HDL-C and lipoprotein(a) levels are not altered in subclinically hypothyroid patients. Smoking and insulin resistance may modify the effects of subclinical hypothyroidism on serum lipid values. Clinical trials to date have not consistently shown a beneficial effect of levothyroxine treatment on serum lipid levels in subclinically hypothyroid patients.

Reversal of small, dense LDL subclass phenotype by weight loss is associated with impaired fat oxidation

Adiposity is more prevalent among individuals with a predominance of small, dense low-density lipoprotein (LDL) (pattern B) particles than among those with larger LDL (pattern A). We tested for differences in resting energy expenditure (REE) and respiratory quotient (RQ) in overweight men with pattern A (n = 36) or pattern B (n = 60). Men consumed a standardized isoenergetic diet for 3 weeks after which a ~9 kg weight loss was induced by caloric deficit for 9 weeks, followed by 4 weeks of weight stabilization. REE and RQ were measured by indirect calorimetry before and after weight loss. Results were analyzed separately in pattern B men who converted to pattern A (B→A; n = 35) and those who did not (B→B; n = 25). At baseline, B→B men had higher trunk fat, triacylglycerol (TG) and insulin concentrations, homeostasis model assessment of insulin resistance (HOMA(IR)), and smaller LDL particles compared to B→A men and baseline pattern A men who remained pattern A (A→A; n = 35). REE normalized to fat-free mass did not change after weight loss. RQ decreased in A→A men, increased in B→A men, and did not change significantly in B→B men after weight loss. Calculated fat oxidation rates paralleled the RQ results. Baseline plasma TG concentrations were positively correlated with RQ and inversely correlated with the magnitude of weight loss achieved for a given prescribed energy reduction in the entire study population. Pattern B men who converted to pattern A with weight loss may have an underlying impairment in fat oxidation that predisposes to both dyslipidemia and an impaired ability to achieve weight loss by energy restriction.

[Disorder of cholesterol metabolism: regulation of intracellular cholesterol and membrane trafficking]

It has been clarified that several transcription factors and functioning proteins play important roles regulating intracellular cholesterol levels. They bind to the ER membrane and sense changes in cholesterol levels in the membrane through SSD. An important membrane-binding transcription factor, SREBP, is retained in the ER membrane, forming an SREBP/SCAP/INSIG trimer when cellular cholesterol levels are abundant. This complex blocks the transport of SREBPs to the Golgi apparatus, thus preventing subsequent transcriptional activation. When cellular cholesterol levels are low, the ER cholesterol concentration is below a threshold value ( <5 mol %). Under these conditions, SCAP escorts SREBPs from the ER to Golgi apparatus by binding to a component of the CopII protein coat. Once in the Golgi apparatus, the SREBPs are proteolytically processed to generate their nuclear form, the bHLH leucine zipper, that activates genes for cholesterol synthesis and uptake. HMG-CoA reductase is also post-transcriptionally regulated by sterol, with INSIG binding of the protein leading to its proteosomal degradation. We demonstrated that Tangier disease and Niemann-Pick disease type B and type C are metabolic disorders of membrane cholesterol. These diseases are not so common in clinical medicine; however, it is very important to understand membrane lipid metabolism, especially in the ER. It will be clarified in the near future disorders of membrane cholesterol trafficking contribute to the pathogeneses of many kinds of disease affecting through ER functioning.

[Research progress and application of shotgun lipidomics]

Following the rapid development of genomics, the omics studies on various metabolites have emerged, expanded, and fused into a novel area of metabolomics. The shotgun lipidomics, as an important approach to lipid researches, has demonstrated great potentials. It will play indispensable roles in biomedical research and applications as its associated techniques are further developed and advanced. Shotgun lipidomics utilizes the mass spectrum technologies to systematically analyze the full scope or a specific subset of lipids from biological samples to identify the differences and the associated functions and to explore the underling mechanisms. The bottleneck problem with the traditional lipid analyses was overcome by the strategy to adopt electro-spray mass spectrum principles, therefore led to a new era of lipidomic researches with high-throughput, high-resolution and high efficiency. The bioactive lipids include many species, widely distributed in living organisms, and closely related to human diseases. Shotgun lipidomics will facilitate the identification of disease-associated specific lipid markers, reveal their roles in the complex processes of the geresis and progress of diseases and eventually provide new strategies and approaches for its diagnosis and treatments.

Is Lipotoxicity presents in the early stages of an experimental model of autoimmune diabetes? Further studies in the multiple low dose of streptozotocin model

An increased availability of plasma free fatty acids (FFA) seems to play a role in the early stages of experimental type 1 diabetes mellitus induced in C57BL/6J mice by multiple low doses of streptozotoxin (mld-STZ). We analyzed the temporal changes of: (1) plasma and skeletal muscle lipids and their relationship with glucose metabolism; (2) triglyceride (Tg) concentration in isolated islets; (3) intraperitoneal glucose tolerance test; and (4) insulin secretion patterns when the three mutually interactive glucose signaling pathways were activated. Animals were killed by cervical dislocation at days 4, 6, 7, 8, 9 and 12 post first injection of mld-STZ. Compared with control mice, we observed: (1) at day 6, a significant increase of plasma FFA and both muscle and islet Tg content and a significant decrease of muscle pyruvate dehydrogenase activity. These parameters further deteriorated with time. (2) plasma Tg, glucose and insulin levels and glucose tolerance test were significantly different only after day 8. (3) an increase in both phases of the glucose plus palmitate-stimulated insulin secretion was observed at day 4. This effect progressively decreased since day 7 up to day 9. Moreover, an inhibitory action of cerulenin over glucose plus palmitate-stimulated insulin secretion was observed between days 6 and 9. Taken together these results suggest that early alteration in carbohydrate and lipid metabolism could represent a "metabolic window" which would develop between days 6 and 8. Afterwards, subsequent immunological alterations, apoptosis and necrosis induced the destruction of β cells and would mask the results mentioned above.

[Ascites and extreme lipid abnormalities as initial symptoms of cystic fibrosis in a 5-years-old girl--case report]

Cystic fibrosis is the most common, multiorgan inherited autosomal recessive disorder. The gene associated with this disease encodes the CF transmembrane conductance regulator (CFTR). The aim of this article is a presentation of 5-years-old girl with cystic fibrosis and associated liver disease as the only manifestation of CF.

CASE REPORT

We described the case of a 5.5-years-old girl with ascites and peripheral edema without of the symptoms. Laboratory tests revealed hepatic cell damage with cholestasis, extreme lipid abnormalities and hypocholesterolemia. Based on positive sweat test (CI: 122 mEq/l) and genetic analysis (homozygote deltaF508) the diagnosis of cystic fibrosis was confirmed. Patient was successfully treated with nutritional treatment and pancreatic enzymes.

Lipid disorders in type 1 diabetes

Patients with type 1 diabetes (T1D) also present with lipid disorders. Quantitative abnormalities of lipoproteins are observed in T1D patients with poor glycaemic control (increased plasma triglycerides and low-density lipoprotein [LDL] cholesterol) or nephropathy (increased triglycerides and LDL cholesterol, low level of high density lipoprotein [HDL] cholesterol). In cases of T1D with optimal glycaemic control, plasma triglycerides and LDL cholesterol are normal or slightly decreased, while HDL cholesterol is normal or slightly increased. Several qualitative abnormalities of lipoproteins, which are potentially atherogenic, are observed in patients with T1D, even in those with good metabolic control. These abnormalities include increased cholesterol-to-triglyceride ratios within very low-density lipoprotein (VLDLs), increased triglycerides in LDLs and HDLs, compositional changes in the peripheral layer of lipoproteins, glycation of apolipoproteins, increased oxidation of LDLs and an increase in small, dense LDL particles. These qualitative changes in lipoproteins are likely to impair their function. In vitro, VLDLs and LDLs from patients with T1D induced abnormal responses in the cellular cholesterol metabolism of human macrophages. HDLs from patients with T1D are thought to be less effective in promoting cholesterol efflux from cells, and have been shown to have reduced antioxidative and vasorelaxant properties. These qualitative abnormalities are not fully explained by hyperglycaemia and may be partly due to peripheral hyperinsulinaemia associated with subcutaneous insulin administration. However, the precise consequences of these qualitative lipid changes on the development of cardiovascular disease in T1D are, as yet, unknown.

Shotgun lipidomics of neutral lipids as an enabling technology for elucidation of lipid-related diseases

Neutral lipids fulfill multiple specialized roles in cellular function. These roles include energy storage and utilization, the synthesis of complex lipids in cellular membranes, lipid second messengers for cellular signaling, and the modulation of membrane molecular dynamics. We have developed a novel mass spectrometric technology, now termed shotgun lipidomics, that can identify the types and amounts of thousands of lipids directly from extracts of biological samples. Shotgun lipidomics is well suited for the identification and measurement of the types and amounts of neutral lipid classes and individual molecular species through the use of multidimensional mass spectrometry. This review summarizes the basic principles underlying the use of shotgun lipidomics for the direct measurement of neutral lipids from extracts of biological tissues or fluids. Through exploiting the high information content inherent in shotgun lipidomics, this technology promises to greatly facilitate advances in our understanding of alterations in neutral lipid metabolism in health and disease.

[Exploratory study on the association between high iodine intake and lipid]

OBJECTIVE

To explore the association between excessive iodine intake and lipid disorder in human bodies.

METHODS

Based on the NTTST sample survey on water iodine in Suining of Jiangsu province, this study involved 81 residents whose drinking water containing excessive iodine and 101 residents who drank water with normal iodine content. Blood samples were tested and compared on lipids (TG, TC, HDL-C, LDL-C, apoA1, apoB) between the two groups, after adjusting the influences of age and gender. The study also compared the abnormal rate of each lipid indicator between the two groups. Corresponding RR values and 95% confidence interval were calculated. Correlation between iodine content in drinking water and blood lipid was also studied.

RESULTS

apoA1 in the group with excessive iodine intake was significantly lower than that in the normal iodine group, while there were no significant differences between the two groups in other lipid indicators. The abnormal rate of HDL-C of excess iodine group (16.88%) was significantly higher than the rate of normal iodine group (7.22%) while there were no significant differences between the two groups in other lipid indicators. Both apoA1 and HDL-C in the excess iodine group had a negative correlation with water iodine, while the other indicators of two groups had no correlation with water iodine.

CONCLUSION

Drinking water with excess iodine might increase the risk of lipid disorder.

Role of hypoxia in obesity-induced disorders of glucose and lipid metabolism in adipose tissue

Recent studies suggest that adipose tissue hypoxia (ATH) may contribute to endocrine dysfunction in adipose tissue of obese mice. In this study, we examined hypoxia's effects on metabolism in adipocytes. We determined the dynamic relationship of ATH and adiposity in ob/ob mice. The interstitial oxygen pressure (Po(2)) was monitored in the epididymal fat pads for ATH. During weight gain from 39.5 to 55.5 g, Po(2) declined from 34.8 to 20.1 mmHg, which are 40-60% lower than those in the lean mice. Insulin receptor-beta (IRbeta) and insulin receptor substrate-1 (IRS-1) were decreased in the adipose tissue of obese mice, and the alteration was observed in 3T3-L1 adipocytes after hypoxia (1% oxygen) treatment. Insulin-induced glucose uptake and Akt Ser(473) phosphorylation was blocked by hypoxia in the adipocytes. This effect of hypoxia exhibited cell type specificity, as it was not observed in L6 myotubes and betaTC6 cells. In response to hypoxia, free fatty acid (FFA) uptake was reduced and lipolysis was increased in 3T3-L1 adipocytes. The molecular mechanism of decreased fatty acid uptake may be related to inhibition of fatty acid transporters (FATP1 and CD36) and transcription factors (PPARgamma and C/EBPalpha) by hypoxia. The hypoxia-induced lipolysis was observed in vivo after femoral arterial clamp. Necrosis and apoptosis were induced by hypoxia in 3T3-L1 adipocytes. These data suggest that ATH may promote FFA release and inhibit glucose uptake in adipocytes by inhibition of the insulin-signaling pathway and induction of cell death.

Primary and secondary disorders of lipid metabolism in pediatrics

In the circulation, cholesterol and triglycerides are enveloped in apolipoproteins and phospholipids, and transported as complex particles called lipoproteins. Abnormal levels of lipoproteins occur in children either because of a genetic defect in lipid metabolism pathways (primary lipid disorders, e.g. familial hypercholesterolemia [FH]) or secondary to other diseases or conditions (e.g. insulin resistance) and can be clinically significant; for example, elevated low-density lipoprotein cholesterol levels are a major risk factor for future cardiovascular disease. Patients with primary lipid disorders in childhood such as FH can exhibit early atherosclerotic lesions in childhood. Other risk factors for cardiovascular disease, such as obesity and type 2 diabetes mellitus, are increasingly common in the pediatric population, and are often associated with dyslipidemia. Thus, pediatricians should be aware of how to screen, diagnose and treat dyslipidemia. The majority of lipid disorders in children can be managed with diet and lifestyle modification. Pharmacologic therapy (e.g. statins) may be added if target lipoprotein levels are not achieved. Clinicians may be guided in patient management by recent scientific statements from the American Heart Association; however, existing National Cholesterol Education Program treatment guidelines should be urgently updated to incorporate new evidence regarding atherosclerosis pathophysiology, obesity and the metabolic syndrome, emerging cardiovascular risk factors, and pharmacologic therapy in pediatric patients.

Progressive myopathy with a combined respiratory chain defect including Complex II

Biochemical defects in the respiratory chain are mostly associated with deficiencies in Complexes I, III and IV, caused by nuclear or mitochondrial DNA mutations. Combined defects including Complex II have been reported very rarely and have muscular symptoms as the main manifestation, including muscle weakness, exercise intolerance and myoglobinuria. We report a patient with a fatal progressive myopathy and muscle biopsy showing diffuse reduction in succinate dehydrogenase activity, ragged red fibers and intense lipid accumulation. Cytochrome c oxidase (COX) histochemistry demonstrated 30% of fibers with increased subsarcolemmal staining while 27% were COX negative. Western blotting analysis showed reduction in the expression of the 39 kDa subunit of Complex I, subunit II of Complex IV and the 70 kDa subunit of Complex II. Our findings suggest that the patient had a complex pattern of mitochondrial dysfunction affecting multiple respiratory chain complexes (I, II and IV) and fatty acid metabolism. This report adds a new histological pattern associated to combined deficiencies of respiratory chain with involvement of Complex II and shows that this disease may be fatal with a rapid progression.

Very low density lipoprotein and low density lipoprotein isolated from patients with hepatitis C infection induce altered cellular lipid metabolism

Several abnormalities of lipid metabolism, including hypo-beta-lipoproteinemia and liver steatosis are associated with infection by hepatitis C virus (HCV). The aim of this study was to determine whether circulating lipoproteins of patients with HCV infection could directly cause alterations of lipid cellular metabolism. To this end the metabolic response of human monocyte-derived macrophages (HMDM) to very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL), measuring the cholesteryl ester (CE) and triglyceride (TG) production was analyzed. Lipoproteins were isolated from 18 patients infected with hepatitis C virus (HCV-VLDL and HCV-LDL) and from normal healthy donors (ct-VLDL and ct-LDL). In comparison to ct-lipoproteins, HCV-lipoproteins induced significant differences in HMDM CE and TG production. HCV-VLDL decreased CE and TG production; while HCV-LDL induced an increased TG synthesis. The present findings suggest that HCV infection modifies VLDL and LDL molecular composition, affecting cellular lipid metabolism, thus promoting intracellular lipid accumulation and hypo-beta-lipoproteinemia.