The inflammatory changes of adipose tissue in late pregnant mice

GRIM-19 deficiency promotes macrophage polarization to the M1 phenotype partly through glycolysis in unexplained recurrent spontaneous abortion†

The occurrence of unexplained recurrent spontaneous abortion (URSA) is closely related to immune system disorders, however, the underlying mechanisms remain unclear. The purpose of this study was to investigate the expression of GRIM-19 in URSA and the possible pathogenesis of URSA according to macrophage polarization. Here, we showed that GRIM-19 was downregulated in the uterine decidual macrophages of patients with URSA and that GRIM-19 downregulation was accompanied by increased M1 macrophage polarization. Furthermore, the expression levels of glycolytic enzymes were substantially enhanced in the uterine decidual macrophages of URSA patients, and glycolysis in THP-1-derived macrophages was further enhanced by the downregulation of GRIM-19. Additionally, the increase of M1 macrophages resulting from the loss of GRIM-19 was significantly reversed in cells treated with 2-deoxy-D-glucose (2-DG, an inhibitor of glycolysis). To provide more direct evidence, GRIM-19 deficiency was shown to promote macrophage polarization to the M1 phenotype in GRIM-19+/- mouse uteri. Overall, our study provides evidence that GRIM-19 deficiency may play a role in regulating macrophage polarization in URSA, and that glycolysis may participate in this process.

Anti-Inflammatory Activities of Monoterpene and Sesquiterpene Glycosides from the Aqueous Extract of Artemisia annua L

Artemisia annua L. is a Chinese medicinal herb, but the origin of its pharmacological properties, including its anti-inflammatory activity, remain unknown. In this study, five new monoterpene glycosides (1-5) and two new sesquiterpene glycosides (6 and 7) were isolated from the aqueous extract of the aerial parts of A. annua. The structures of these glycosides were determined using high-resolution electrospray ionization mass spectrometry, nuclear magnetic resonance spectroscopy, electronic circular dichroism calculations, and chemical hydrolysis methods. The anti-inflammatory activities of the isolated compounds were evaluated by down-regulating interleukin-6 (IL-6) in lipopolysaccharide-stimulated RAW 264.7 macrophages. Notably, all the new compounds significantly inhibited the expression of IL-6 in a dose-dependent manner.

Regulation of maternal-fetal metabolic communication

Pregnancy may be the most nutritionally sensitive stage in the life cycle, and improved metabolic health during gestation and early postnatal life can reduce the risk of chronic disease in adulthood. Successful pregnancy requires coordinated metabolic, hormonal, and immunological communication. In this review, maternal-fetal metabolic communication is defined as the bidirectional communication of nutritional status and metabolic demand by various modes including circulating metabolites, endocrine molecules, and other secreted factors. Emphasis is placed on metabolites as a means of maternal-fetal communication by synthesizing findings from studies in humans, non-human primates, domestic animals, rabbits, and rodents. In this review, fetal, placental, and maternal metabolic adaptations are discussed in turn. (1) Fetal macronutrient needs are summarized in terms of the physiological adaptations in place to ensure their proper allocation. (2) Placental metabolite transport and maternal physiological adaptations during gestation, including changes in energy budget, are also discussed. (3) Maternal nutrient limitation and metabolic disorders of pregnancy serve as case studies of the dynamic nature of maternal-fetal metabolic communication. The review concludes with a summary of recent research efforts to identify metabolites, endocrine molecules, and other secreted factors that mediate this communication, with particular emphasis on serum/plasma metabolomics in humans, non-human primates, and rodents. A better understanding of maternal-fetal metabolic communication in health and disease may reveal novel biomarkers and therapeutic targets for metabolic disorders of pregnancy.

Recruitment of monocytes and mature macrophages in mouse pubic symphysis relaxation during pregnancy and postpartum recovery†

Appropriate remodeling of the female lower reproductive tract and pelvic floor is essential during normal mammalian pregnancy, labor, and postpartum recovery. During mouse pregnancy, in addition to reproductive tract modifications, the pubic symphysis (PS) is remodeled into a soft interpubic ligament (IpL) to provide safe delivery of the offspring and fast postpartum recovery. Although temporal changes in the phenotypes of myeloid cells, such as mononuclear phagocytes, are crucial to remodeling the lower reproductive tract organs in preparation for a safe delivery, little is known about the involvement of recruited monocytes or macrophages in mouse PS remodeling. We used combined light microscopy, electron microscopy, and qPCR analysis to investigate the profile of recruited monocytes and macrophage polarization markers in C57Bl6 mouse interpubic tissues during pregnancy (D12, D18, and D19) and early days postpartum (1 dpp and 3 dpp) to better identify their presence in proper remodeling of the mouse PS. Our morphological data show that the number of recruited monocytes is increased in interpubic tissues and that recruited monocytes differentiate into proinflammatory or anti-inflammatory macrophage phenotypes from D18 to 3 dpp, which may contribute to dynamic changes in the gene expression of specific inflammatory mediators involved in interpubic tissue remodeling at these time points. Therefore, our morphological and quantitative gene expression data suggest that both differentiated macrophages from recruited monocytes and polarized macrophages may collaborate for IpL relaxation at labor and the appropriate repair of the PS after the first pregnancy.

Evidence of macrophage modulation in the mouse pubic symphysis remodeling during the end of first pregnancy and postpartum

In mouse pregnancy, pubic symphysis (PS) remodels into an elastic interpubic ligament (IpL) in a temporally regulated process to provide safe delivery. It restores at postpartum to assure reproductive tract homeostasis. Recently, macrophage localization in the IpL and dynamic changes in the expression of inflammatory mediators observed from the end of pregnancy (D18, D19) to early days postpartum (1dpp, 3dpp) highlighted the necessity of the identification of the key molecules involved in innate immune processes in PS remodeling. Therefore, this study uses morphological and high-sensitivity molecular techniques to identify both macrophage association with extracellular matrix (ECM) remodeling and the immunological processes involved in PS changes from D18 to 3dpp. Results showed macrophage association with active gelatinases and ECM components and 25 differentially expressed genes (DEGs) related to macrophage activities in interpubic tissues from D18 to 3dpp. Additionally, microarray and proteomic analysis showed a significant association of interpubic tissue DEGs with complement system activation and differentially expressed proteins (DEPs) with phagocytosis, highlighting the involvement of macrophage-related activities in mouse PS remodeling. Therefore, the findings suggest that PS ECM remodeling is associated with evidence of macrophage modulation that ensures both IpL relaxation and fast PS recovery postpartum for first labor.

Systematic review: chronic viral hepatitis and metabolic derangement

BACKGROUND

The liver has a critical role in the metabolism of glucose and lipids. Chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infection leads to a spectrum of liver disease including chronic hepatitis, cirrhosis and hepatocellular carcinoma. Metabolic syndrome (MetS) has a rising incidence owing to an epidemic of type 2 diabetes mellitus (T2DM) and obesity. Non-alcoholic fatty liver disease is a liver manifestation of MetS and has become the most common cause of chronic liver disease worldwide.

AIM

To summarise the interplay among hepatitis viruses, MetS and its components.

METHODS

We searched the literature about HBV, HCV infection, MetS, fatty liver and its components from PubMed.

RESULTS

With respect to the viral replication cycle, lipids are important mediators between viral entry and hepatocyte in HCV infection, but not in HBV infection. Thus, HCV infection is inversely associated with hyperlipidaemia and lipid rebound occurs following sustained viral response induced by interferon-based therapy or direct antiviral agents. In addition, HCV infection is positively associated with insulin resistance, hepatic steatosis, MetS and the risk of T2DM and atherosclerosis. In contrast, HBV infection may protect infected subjects from the development of MetS and hepatic steatosis. Accumulating evidence suggests that HBV infection is inversely associated with lipid metabolism, and exhibits no conclusive association with insulin resistance or the risk of T2DM and arteriosclerosis.

CONCLUSIONS

In patients with viral hepatitis and concurrent metabolic diseases, a multidisciplinary approach should be given rather than simply antiviral treatment.

Obeticholic acid ameliorates dyslipidemia but not glucose tolerance in mouse model of gestational diabetes

Metabolism alters markedly with advancing gestation, characterized by progressive insulin resistance, dyslipidemia, and raised serum bile acids. The nuclear receptor farnesoid X receptor (FXR) has an integral role in bile acid homeostasis and modulates glucose and lipid metabolism. FXR is known to be functionally suppressed in pregnancy. The FXR agonist, obeticholic acid (OCA), improves insulin sensitivity in patients with type 2 diabetes with nonalcoholic fatty liver disease. We therefore hypothesized that OCA treatment during pregnancy could improve disease severity in a mouse model of gestational diabetes mellitus (GDM). C57BL/6J mice were fed a high-fat diet (HFD; 60% kcal from fat) for 4 wk before and throughout pregnancy to induce GDM. The impact of the diet supplemented with 0.03% OCA throughout pregnancy was studied. Pregnant HFD-fed mice displayed insulin resistance and dyslipidemia. OCA significantly reduced plasma cholesterol concentrations in nonpregnant and pregnant HFD-fed mice (by 22.4%, P < 0.05 and 36.4%, P < 0.001, respectively) and reduced the impact of pregnancy on insulin resistance but did not change glucose tolerance. In nonpregnant HFD-fed mice, OCA ameliorated weight gain, reduced mRNA expression of inflammatory markers in white adipose tissue, and reduced plasma glucagon-like peptide 1 concentrations (by 62.7%, P < 0.01). However, these effects were not evident in pregnant mice. OCA administration can normalize plasma cholesterol levels in a mouse model of GDM. However, the absence of several of the effects of OCA in pregnant mice indicates that the agonistic action of OCA is not sufficient to overcome many metabolic consequences of the pregnancy-associated reduction in FXR activity.

Circulating Pro-Neurotensin in gestational diabetes mellitus

BACKGROUND AND AIMS

Pro-Neurotensin (NT), a stable surrogate parameter of NT, has recently been introduced as a peptide predicting the development of obesity, diabetes mellitus, cardiovascular diseases, and cardiovascular mortality. However, regulation of Pro-NT in gestational diabetes mellitus (GDM) remains uninvestigated.

METHODS AND RESULTS

Pro-NT was quantified in 74 women with GDM, 74 healthy, gestational age-matched, pregnant controls, as well as in a second cohort comprising of 74 healthy, non-pregnant control women, using a chemiluminometric sandwich immunoassay. Pro-NT was correlated to measures of obesity, hypertension, glucose and lipid metabolism, renal function, and inflammation. Mean ± standard deviation of circulating Pro-NT levels were not significantly different in women with GDM (100.2 ± 75.7 pmol/l) as compared to healthy, pregnant controls (103.2 ± 37.4 pmol/l) and healthy, non-pregnant female controls (105.9 ± 38.9 pmol/l) (p = 0.661). Homeostasis model assessment of insulin resistance (HOMA-IR) and creatinine positively correlated with serum Pro-NT in multivariate regression analysis. In contrast, free fatty acids (FFA) were inversely correlated with circulating Pro-NT. Results sustained adjustment for pregnancy status.

CONCLUSIONS

Circulating Pro-NT is not independently associated with GDM, but is with HOMA-IR, creatinine, and FFA even after adjustment for pregnancy status.

Depletion of dendritic cells in perivascular adipose tissue improves arterial relaxation responses in type 2 diabetic mice

BACKGROUND

Accumulation of multiple subtypes of immune cells in perivascular adipose tissue (PVAT) has been proposed to cause vascular inflammation and dysfunction in type 2 diabetes (T2DM). This study was designed to investigate specific roles for dendritic cells in PVAT in the development of vascular inflammation and impaired PVAT-mediated vasorelaxation in T2DM.

METHODS AND RESULTS

Studies were performed using db/db mice (model of T2DM) and their Db heterozygote (DbHET), lean and normoglycemic controls. Dendritic cell depletion was performed by cross-breeding DbHet with Flt3l-/- (null for ligand for FMS-kinase tyrosine kinase) mice. Using PCR, it was found that the majority of dendritic cells (CD11c+) were located in PVAT rather than the vascular wall. Flow cytometry similarly showed greater dendritic cell accumulation in adipose tissue from db/db mice than DbHET controls. Adipose tissue from db/db mice displayed increased mRNA levels of proinflammatory cytokines TNF-α and IL-6 and decreased mRNA levels of the anti-inflammatory mediator adiponectin, compared to DbHET mice. Depletion of dendritic cells in dbFlt3l-/dbFlt3l- (confirmed by flow cytometry) reduced TNF-α and IL-6 mRNA levels in diabetic adipose tissue without influencing adiponection expression. Moreover, in mesenteric arteries, dendritic cell depletion improved the ability of PVAT to augment acetylcholine-induced vasorelaxation and anti-contractile activity.

CONCLUSIONS

In a murine model of T2DM, dendritic cells accumulated predominantly in PVAT, as opposed to the vessel wall, per se. Accumulation of dendritic cells in PVAT was associated with overproduction of pro-inflammatory cytokines, which contributed to an impaired ability of PVAT to augment vasorelaxation and exert anti-contractile activity in T2DM.

Fgf21 is required for cardiac remodeling in pregnancy

Aims

Fibroblast growth factor-21 (Fgf21) is an endocrine factor that contributes to many physiological and pathological processes, mainly via its action as a metabolic regulator. Recent studies have shown that Fgf21 plays an important role in cardiac tissue. Pregnancy offers a physiological model of adaptive and reversible heart enlargement, but the molecular mechanisms underlying this cardiac hypertrophy are poorly understood. Therefore, the aim was to analyze the role of Fgf21 during late pregnancy, and assess the physiological relevance of Fgf21 for cardiac tissue during this process.

Methods and results

Female mice and rats at day 18 of gestation and pregnant women in their third trimester were used as models of late pregnancy, and our results revealed that their plasma levels of Fgf21 were significantly increased relative to non-pregnant controls. Pregnant wild-type (wt) mice exhibited a PPARα (peroxisome proliferator-activated receptor-α)-dependent enhancement of Fgf21 expression in the liver and heart. Moreover, pregnancy altered the levels of Fgf21 receptor-1 (FGFR1) and β-klotho, and activated intracellular Fgf21 signaling in the heart. Fgf21-/- mice did not develop the pregnancy-induced cardiac remodeling seen in wt mice. Furthermore, the hearts of Fgf21-/- mice exhibited reductions in their fatty acid oxidation levels, which may compromise cardiac function during pregnancy.

Conclusions

During pregnancy, both systemic and cardiac-produced Fgf21 act on the heart, leading to the normal physiological cardiac changes that are associated with pregnancy. Thus, Fgf21 acts as an endocrine/autocrine factor required for cardiac remodeling response to gestation.

Pregnancy late in rodent life has detrimental effects on the heart

During pregnancy, the heart undergoes significant and numerous changes, including hypertrophy, that are usually described as physiological and reversible. Two aspects of the cardiac response to pregnancy are relatively understudied: advanced maternal age and multiple pregnancies (multiparity). Repeated breeder (RB) mice that have undergone five to seven consecutive pregnancies were euthanized 21 days after the weaning of their last pups and compared with age-matched primiparous, one-time pregnant (O1P) mice. The ages of the older mouse groups were similar (12 ± 1 mo). Pregnancy at a later age resulted in reduced fertility (40%); resorption was 29%, maternal mortality was 10%, and mortality of the pups was 17%. Contractile function as indicated by percent fractional shortening was significantly decreased in O1P and RB groups compared with the old nonpregnant control (ONP) group. There was no pathological induction of the fetal program of gene expression, with the exception of β-myosin heavy chain mRNA, which was induced in O1P compared with ONP mice ( P < 0.05) but not in RB mice. MicroRNA-208a was significantly increased in O1P compared with ONP mice ( P < 0.05) but significantly decreased in RB compared with ONP mice ( P < 0.05). mRNA of genes regulating angiogenesis (i.e., vascular endothelial growth factor-A) were significantly downregulated, whereas proinflammatory genes [i.e., interleukin-6, chemokine (C-C motif) ligand 2, and Cd36] were significantly upregulated in O1P ( P < 0.05) but not in RB mice. Overall, our results suggest that rather than multiparity, pregnancy in advanced age is a much more stressful event in both pregnant dams and fetuses, as evidenced by increased mortality, lower fertility, downregulation of angiogenesis, upregulation of inflammation, and cardiac dysfunction. NEW & NOTEWORTHY Pregnancy in older mice significantly decreases cardiac function, although repeated breeder mice demonstrated increased wall hypertrophy and dilated chamber size compared with one-time pregnant mice. Interestingly, many of the molecular changes were altered in one-time pregnant mice but not in repeated breeder mice, which may contribute to adverse pregnancy outcomes in a first pregnancy at a later age.

Macrophage Populations in Visceral Adipose Tissue from Pregnant Women: Potential Role of Obesity in Maternal Inflammation

Obesity is associated with inflammatory changes and accumulation and phenotype polarization of adipose tissue macrophages (ATMs). Obese pregnant women have alterations in adipose tissue composition, but a detailed description of macrophage population is not available. In this study, we characterized macrophage populations in visceral adipose tissue (VAT) from pregnant women with normal, overweight, and obese pregestational weight. Immunophenotyping of macrophages from VAT biopsies was performed by flow cytometry using CD45 and CD14 as markers of hematopoietic and monocyte linage, respectively, while HLA-DR, CD11c, CD163, and CD206 were used as pro- and anti-inflammatory markers. Adipocyte number and size were evaluated by light microscopy. The results show that pregnant women that were overweight and obese during the pregestational period had adipocyte hypertrophy. Two different macrophage populations in VAT were identified: recruited macrophages (CD45⁺CD14⁺), and a novel population lacking CD45, which was considered to be a resident macrophages subset (CD45⁻CD14⁺). The number of resident HLA⁻DR^low/− macrophages showed a negative correlation with body mass index (BMI). Both resident and recruited macrophages from obese women expressed higher CD206 levels. CD11c expression was higher in resident HLA-DR⁺ macrophages from obese women. A strong correlation between CD206 and CD11c markers and BMI was observed. Our findings show that being overweight and obese in the pregestational period is associated with adipocyte hypertrophy and specific ATMs populations in VAT.

Effects of hereditary moderate high fat diet on metabolic performance and physical endurance capacity in C57BL/6 offspring

Obesity in pregnant women presents a risk to fetal health, leading to numerous metabolic syndromes and chronic inflammation risks. Previously, physical exercise was considered to be one of the primary treatments for obesity. However, the effect of fat consumption throughout the life cycle on physical endurance capacity remains unknown. A total of two groups of female mice (age, 6 weeks; C57BL/6J) were fed with a normal chow diet and a moderate high fat diet (MHFD), during pregnancy and lactation (8 weeks), with the offspring receiving the same diet as the mother. When filial mice were 8, 16 and 24 weeks old, they were tested for endurance, blood pressure (BP) and glucose tolerance, as well as adipose tissue infiltration and macrophage subtype. Compared with the control group, filial mice in MHFD groups exhibited increased BP and glucose levels and larger adipose cells (~4‑fold). During adolescence, the obese filial mice demonstrated increased endurance compared with controls. Endurance declines in middle and old age; the endurance of aged obese mice was 29% that of lean ones. In addition, body coordination and movement memory did not notably change. The expression of cluster of differentiation 68, one of the most reliable markers of macrophages, increased by 2.48‑fold, demonstrating that macrophages were recruited and underwent infiltration. In addition, increased tumor necrosis factor‑α and decreased interleukin‑10 expression demonstrated that infiltrated macrophages are polarized to the M1 state, which weakens physical endurance and resists type M2 macrophages, which exhibit repairing functions. In conclusion, hereditary MHFD weakens physical endurance and alters the metabolic characteristics of C57BL/6 offspring.

Programming of infant neurodevelopment by maternal obesity: potential role of maternal inflammation and insulin resistance

BACKGROUND AND OBJECTIVES

Recent studies show that maternal obesity is associated with impaired offspring neurodevelopmental outcomes. The mechanism underlying the association is unclear. However, there is evidence to suggest a role for intra-uterine exposure to inflammation and insulin resistance (IR). We aimed to determine if maternal IR and inflammation were associated to fetal neurodevelopment as indicated by fetal heart rate variability (HRV), an index of fetal cardiac autonomic nervous system development.

METHODS AND STUDY DESIGN

A total of 44 healthy maternal-fetal pairs (maternal pre-pregnancy BMI distribution: n=20 normal weight, 8 overweight, 16 obese) were analyzed. We assessed maternal inflammation (plasma IL-6 and TNF-α) and IR (HOMA index). Fetal HRV, a proxy for fetal neurodevelopment, was assessed using fetal magnetocardiogram at the 36th week of pregnancy. The relationships between maternal inflammation and IR with fetal HRV (SD1 and SD2) were estimated individually by Pearson bivariate correlations.

RESULTS

No correlations were observed between the fetal HRV components with maternal HOMA-IR and maternal plasma levels of IL-6 and TNF-α (all p<0.05). However, the negative association between maternal TNF-α level and fetal SD2 approached significance (correlation coefficient=-0.29, 95% confidence interval=-0.62,-0.03, p=0.07).

CONCLUSION

Maternal IR and inflammation during pregnancy were not associated with fetal cardiac autonomic nervous system development. Further studies with a larger sample size and more maternal inflammatory indicators are needed to explore these relationships.

The TIR/BB-loop mimetic AS-1 prevents non-alcoholic steatohepatitis and hepatic insulin resistance by inhibiting NLRP3-ASC inflammasome activation

BACKGROUND AND PURPOSE

Non-alcoholic steatohepatitis (NASH) is characterized by excessive intracellular lipid accumulation, inflammation and hepatic insulin resistance. As the incidence of NASH is increasing worldwide, there is an urgent need to find novel interventional approaches. The pro-inflammatory cytokine IL-1β, generated and released from Kupffer cells, is considered to initiate the development of NASH. AS-1, a synthetic low-molecule mimetic of myeloid differentiation primary response gene 88 (MyD88), disrupts the interaction between the IL-1 receptor and MyD88. Here, we investigated whether AS-1 could attenuate the pathogenesis of NASH with an emphasis on hepatic insulin resistance.

EXPERIMENTAL APPROACH

Eight-week-old db/db mice were fed a control diet or a methionine- and choline-deficient (MCD) diet. AS-1 (50 mg·kg^-1 ) or vehicle was administered i.p.

KEY RESULTS

AS-1 administration significantly ameliorated NASH as evidenced by alanine aminotransferase levels and CD68 levels in livers of MCD-fed mice. AS-1 inhibited the MCD diet-induced activation of caspase 1 and the NLRP3-ASC inflammasome, and also reduced the enhanced levels of ROS, malondialdehyde, 3-nitrotyrosine, NADPH oxidase complex and CYP reductase-associated cytochrome p450 2E1 (CYP2E1) expression in the liver. In addition, AS-1 decreased ROS, inflammasome activation and IL-1β production in free fatty acid-LPS-treated Kupffer cells. Finally, pretreatment with AS-1 significantly ameliorated gluconeogenesis and insulin desensitization induced by IL-1β, probably by blocking the interaction between MyD88 and the IL-1 receptor.

CONCLUSIONS AND IMPLICATIONS

Our results indicate that AS-1 can ameliorate NASH and hepatic insulin resistance and could be considered as a potential strategy for the prevention and treatment of NASH.

The impact of maternal obesity on inflammatory processes and consequences for later offspring health outcomes

Obesity is a global epidemic, affecting both developed and developing countries. The related metabolic consequences that arise from being overweight or obese are a paramount global health concern, and represent a significant burden on healthcare systems. Furthermore, being overweight or obese during pregnancy increases the risk of offspring developing obesity and other related metabolic complications in later life, which can therefore perpetuate a transgenerational cycle of obesity. Obesity is associated with a chronic state of low-grade metabolic inflammation. However, the role of maternal obesity-mediated alterations in inflammatory processes as a mechanism underpinning developmental programming in offspring is less understood. Further, the use of anti-inflammatory agents as an intervention strategy to ameliorate or reverse the impact of adverse developmental programming in the setting of maternal obesity has not been well studied. This review will discuss the impact of maternal obesity on key inflammatory pathways, impact on pregnancy and offspring outcomes, potential mechanisms and avenues for intervention.

Loss of Anticontractile Effect of Perivascular Adipose Tissue on Pregnant Rats: A Potential Role of Tumor Necrosis Factor-α

The present investigation examined the effect of pregnancy on the anticontractile effect of perivascular adipose tissue (PVAT) on the rat. Ring segments of the aorta, with and without PVAT, were set up in organ baths for isometric tension recording. In both groups, concentration-response curves to 5-hydroxytryptamine (5-HT) were displaced to the right with a reduction of the maximum response in aorta segments with PVAT. The anticontractile effect of PVAT was attenuated on segments from pregnant rats. 4-Aminopyridine (4-AP), an inhibitor of voltage-gated potassium (Kv) channels, enhanced 5-HT-induced contractions of aorta segments from pregnant and nonpregnant rats only when PVAT was attached. There was no difference in the effect of 4-aminopyridine on 5-HT-induced contractions of aorta segments with PVAT from pregnant and nonpregnant rats. There was also no significant difference in the expression of Kv7.4 channels in aorta segments (with PVAT) between pregnant and nonpregnant rats. Tumor necrosis factor-α (TNF-α) was detected in PVAT from pregnant and nonpregnant rats. The level of TNF-α was significantly greater in PVAT from pregnant rats. Treatment of pregnant rats with pentoxyphyline significantly reduced the level of TNF-α in the PVAT and restored the anticontractile effect of PVAT on aorta segments from pregnant rats. Finally, TNF-α (10 ng/mL) potentiated 5-HT-induced contractions of PVAT-containing pregnant rat aorta. These results would suggest that the loss of anticontractile effect of PVAT in pregnant rat aorta could be due to enhanced production of TNF-α in the PVAT in these rats.

Peroxisome proliferator activated receptor gamma 2 modulates late pregnancy homeostatic metabolic adaptations

Pregnancy requires the adaptation of maternal energy metabolism including expansion and functional modifications of adipose tissue. Insulin resistance (IR), predominantly during late gestation, is a physiological metabolic adaptation that serves to support the metabolic demands of fetal growth. The molecular mechanisms underlying these adaptations are not fully understood and may contribute to gestational diabetes mellitus. Peroxisome proliferator-activated receptor gamma (PPARγ) controls adipogenesis, glucose and lipid metabolism and insulin sensitivity. The PPARγ2 isoform is mainly expressed in adipocytes and is thus likely to contribute to adipose tissue adaptation during late pregnancy. In the present study, we investigated the contribution of PPARγ2 to the metabolic adaptations occurring during the late phase of pregnancy in the context of IR. Using a model of late pregnancy in PPARγ2 knockout (KO) mice, we found that deletion of PPARγ2 exacerbated IR in association with lower serum adiponectin levels, increased body weight and enhanced lipid accumulation in liver. Lack of PPARγ2 provoked changes in the distribution of fat mass and preferentially prevented the expansion of the perigonadal depot while at the same time exacerbating inflammation. PPARγ2KO pregnant mice presented adipose tissue depot-dependent decreased expression of genes involved in lipid metabolism. Collectively, these data indicate that PPARγ2 is essential to promote healthy adipose tissue expansion and immune and metabolic functionality during pregnancy, contributing to the physiological adaptations that lead gestation to term.

Altered cytokine network in gestational diabetes mellitus affects maternal insulin and placental-fetal development

Pregnancy is characterized by an altered inflammatory profile, compared to the non-pregnant state with an adequate balance between pro-and anti-inflammatory cytokines needed for normal development. Cytokines are small secreted proteins expressed mainly in immunocompetent cells in the reproductive system. From early developmental stages onward, the secretory activity of placenta cells clearly contributes to increase local as well as systemic levels of cytokines. The placental production of cytokines may affect mother and fetus independently. In turn because of this unique position at the maternal fetal interface, the placenta is also exposed to the regulatory influence of cytokines from maternal and fetal circulations, and hence, may be affected by changes in any of these. Gestational diabetes mellitus (GDM) is associated with an overall alteration of the cytokine network. This review discusses the changes that occur in cytokines post GDM and their negative effects on maternal insulin and placental-fetal development.

Maternal conjugated linoleic acid supplementation reverses high-fat diet-induced skeletal muscle atrophy and inflammation in adult male rat offspring

A high-saturated-fat diet (HFD) during pregnancy and lactation leads to metabolic disorders in offspring concomitant with increased adiposity and a proinflammatory phenotype in later life. During the fetal period, the impact of maternal diet on skeletal muscle development is poorly described, despite this tissue exerting a major influence on life-long metabolic health. This study investigated the effect of a maternal HFD on skeletal muscle anabolic, catabolic, and inflammatory signaling in adult rat offspring. Furthermore, the actions of maternal-supplemented conjugated linoleic acid (CLA) on these measures of muscle phenotype were investigated. A purified control diet (CD; 10% kcal fat), a CD supplemented with CLA (CLA; 10% kcal fat, 1% total fat as CLA), a high-fat (HFD; 45% kcal fat from lard), or a HFD supplemented with CLA (HFCLA; 45% kcal fat from lard, 1% total fat as CLA) was fed ad libitum to female Sprague-Dawley rats for 10 days before mating and throughout gestation and lactation. Male offspring received a standard chow diet from weaning, and the gastrocnemius was collected for analysis at day 150. Offspring from HF and HFCLA mothers displayed lower muscular protein content accompanied by elevated monocyte chemotactic protein-1, IL-6, and IL-1β concentrations. Phosphorylation of NF-κBp65 (Ser536) and expression of the catabolic E3 ligase muscle ring finger 1 (MuRF1) were increased in HF offspring, an effect reversed by maternal CLA supplementation. The present study demonstrates the importance of early life interventions to ameliorate the negative effects of poor maternal diet on offspring skeletal muscle development.

Associations Between Parity, Obesity, and Cardiovascular Risk Factors Among Middle-Aged Women

BACKGROUND

Several studies have demonstrated an association between parity and the risk of developing cardiovascular disease (CVD) in middle-aged women; however, some inconsistencies still remain in the literature after accounting for obesity. The purpose of this study was to examine the association between parity and the risk factors of CVD while accounting for current obesity status in middle-aged women.

METHOD

Data for this study came from the National Health and Nutrition Examination Survey 2007-2012. The final analytic sample included 2024 middle-aged women (40-60 years old). General linear models predicting CVD risk factors based on parity (nulliparous, 1, 2, 3, and ≥4) were established after controlling for study covariates. Least square adjusted means of CVD risk factors and associated 95% confidence intervals were estimated across parity and body mass index (BMI) levels.

RESULTS

Women with ≥4 parity (8.34%; standard error [SE] = 0.84) showed significantly distinct demographic characteristics and health conditions, including obesity (49.08%; SE = 3.55). There were no significant associations between parity and CVD risk factors after controlling for covariates. Follow-up analyses showed consistent results across parity; however, CVD risk factors were significantly increased with higher BMI levels, regardless of parity status.

CONCLUSIONS

Our results suggest that parity is not a significant predictor of CVD risk factors in middle-aged women, whereas current overweight or obesity status is more important when explaining the risk of the development of CVD.

Mice subjected to aP2-Cre mediated ablation of microsomal triglyceride transfer protein are resistant to high fat diet induced obesity

Background

Microsomal triglyceride transfer protein (MTP) is essential for the assembly of lipoproteins. MTP has been shown on the surface of lipid droplets of adipocytes; however its function in adipose tissue is not well defined. We hypothesized that MTP may play critical role in adipose lipid droplet formation and expansion.

Methods

Plasmids mediated overexpression and siRNA mediated knockdown of Mttp gene were performed in 3T3-L1 pre-adipocytes to evaluate the effects of MTP on cell differentiation and triglyceride accumulation. Adipose-specific knockdown of MTP was achieved in mice bybreeding MTP floxed (Mttp^fl/fl) mice with aP2-Cre recombinase transgenic mice. Adipose-specific MTP deficient (A-Mttp^-/-) mice were fed 60 % high-fat diet (HFD), and the effects of MTP knockdown on body weight, body fat composition, plasma and tissues lipid composition, glucose metabolism, lipogenesis and intestinal absorption was studied. Lipids were measured in total fasting plasma and size fractionated plasma using colorimetric assays. Gene expression was investigated by Real-Time quantitative PCR. All data was assessed using t-test, ANOVA.

Results

MTP expression increased during early differentiation in 3T3-L1 cells, and declined later. The increases in MTP expression preceded PPARγ expression. MTP overexpression enhanced lipid droplets formation, and knockdown attenuated cellular lipid accumulation. These studies indicated that MTP positively affects adipogenesis.

The ablation of the Mttp gene using aP2-Cre (A-Mttp^-/-) in mice resulted in a lean phenotype when fed a HFD. These mice had reduced white adipose tissue compared with wild-type Mttp^fl/fl mice. The adipose tissue of A-Mttp^-/- mice had increased number of smaller size adipocytes and less macrophage infiltration. Further, these mice were protected from HFD-induced fatty liver. The A-Mttp^-/- mice had moderate increase in plasma triglyceride, but normal cholesterol, glucose and insulin levels. Gene expression analysis showed that the adipose tissue of the A-Mttp^-/- mice had significantly lower mRNA levels of PPARγ and its downstream targets.

Conclusion

These data suggest that MTP might modulate adipogenesis by influencing PPARγ expression, and play a role in the accretion of lipids to form larger lipid droplets. Thus, agents that inactivate adipose MTP may be useful anti-obesity drugs.

Adiponectin: A biomarker for chronic hepatitis C?

Adiponectin, a hormone primarily synthesized and secreted by adipose tissue, plays a pivotal role in lipid metabolism. Chronic hepatitis C (CHC) infection is characterized by disordered lipid metabolism, which may potentially evolve into steatosis over a period of time. A growing body of evidence appears to link decreased adiponectin plasma levels with severe CHC-related steatosis, which suggests a potential role of this adipokine as a diagnostic and therapeutic target for clinical application. In this review, we have attempted to summarize the current status of adiponectin research in the context of CHC, concentrating predominantly on its roles in CHC, and its potential relevance as a biomarker for CHC.

Characterization of Visceral and Subcutaneous Adipose Tissue Transcriptome and Biological Pathways in Pregnant and Non-Pregnant Women: Evidence for Pregnancy-Related Regional-Specific Differences in Adipose Tissue

Objective

The purpose of this study was to compare the transcriptome of visceral and subcutaneous adipose tissues between pregnant and non-pregnant women.

Study Design

The transcriptome of paired visceral and abdominal subcutaneous adipose tissues from pregnant women at term and matched non-pregnant women (n = 11) was profiled with the Affymetrix Human Exon 1.0 ST array. Differential expression of selected genes was validated with the use of quantitative reverse transcription–polymerase chain reaction.

Results

Six hundred forty-four transcripts from 633 known genes were differentially expressed (false discovery rate (FDR) <0.1; fold-change >1.5), while 42 exons from 36 genes showed differential usage (difference in FIRMA scores >2 and FDR<0.1) between the visceral and subcutaneous fat of pregnant women. Fifty-six known genes were differentially expressed between pregnant and non-pregnant subcutaneous fat and three genes in the visceral fat. Enriched biological processes in the subcutaneous adipose tissue of pregnant women were mostly related to inflammation.

Conclusion

The transcriptome of visceral and subcutaneous fat depots reveals pregnancy-related gene expression and splicing differences in both visceral and subcutaneous adipose tissue. Furthermore, for the first time, alternative splicing in adipose tissue has been associated with regional differences and human parturition.

Maternal obesity and metabolic risk to the offspring: why lifestyle interventions may have not achieved the desired outcomes

Obesity during pregnancy is associated with an increased risk of short- and long-term metabolic dysfunction in the mother and her offspring. Both higher maternal pregravid body mass index (kg m(-2)) and excessive gestational weight gain (GWG) have been associated with adverse pregnancy outcomes such as gestational diabetes, preeclampsia and fetal adiposity. Multiple lifestyle intervention trials consisting of weight management using various diets, increased physical activity and behavioral modification techniques have been employed to avoid excessive GWG and improve perinatal outcomes. These randomized controlled trials (RCTs) have achieved modest success in decreasing excessive GWG, although the decrease in GWG was often not within the current Institute of Medicine guidelines. RCTs have generally not had any success with decreasing the risk of maternal gestational diabetes (GDM), preeclampsia or excessive fetal growth often referred to as macrosomia. Although the lack of success for these trials has been attributed to lack of statistical power and poor compliance with study protocols, our own research suggests that maternal pregravid and early pregnancy metabolic condition programs early placenta function and gene expression. These alterations in maternal/placental function occur in the first trimester of pregnancy prior to when most intervention trials are initiated. For example, maternal accrural of adipose tissue relies on prior activation of genes controlling lipogenesis and low-grade inflammation in early pregnancy. These metabolic alterations occur prior to any changes in maternal phenotype. Therefore, trials of lifestyle interventions before pregnancy are needed to demonstrate the safety and efficacy for both the mother and her offspring.

Do all roads lead to Rome? The role of neuro-immune interactions before birth in the programming of offspring obesity

The functions of the nervous system can be powerfully modulated by the immune system. Although traditionally considered to be quite separate, neuro-immune interactions are increasingly recognized as critical for both normal and pathological nervous system function in the adult. However, a growing body of information supports a critical role for neuro-immune interactions before birth, particularly in the prenatal programming of later-life neurobehavioral disease risk. This review will focus on maternal obesity, as it represents an environment of pathological immune system function during pregnancy that elevates offspring neurobehavioral disease risk. We will first delineate the normal role of the immune system during pregnancy, including the role of the placenta as both a barrier and relayer of inflammatory information between the maternal and fetal environments. This will be followed by the current exciting findings of how immuno-modulatory molecules may elevate offspring risk of neurobehavioral disease by altering brain development and, consequently, later life function. Finally, by drawing parallels with pregnancy complications other than obesity, we will suggest that aberrant immune activation, irrespective of its origin, may lead to neuro-immune interactions that otherwise would not exist in the developing brain. These interactions could conceivably derail normal brain development and/or later life function, and thereby elevate risk for obesity and other neurobehavioral disorders later in the offspring's life.

Adiponectin serum level in chronic hepatitis C infection and therapeutic profile

Hepatic steatosis is commonly seen in the patients with chronic hepatitis C virus (HCV) infection. HCV is closely associated with lipid metabolism, and viral steatosis is more common in genotype 3 infection owing to a direct cytopathic effect of HCV core protein. In non-genotype 3 infection, hepatic steatosis is considered largely to be the result of the alterations in host metabolism; metabolic steatosis is primarily linked with HCV genotype 1. Adipose tissue secretes different hormones involved in glucose and lipid metabolisms. It has been demonstrated that adipocytokines are involved in the pathogenesis of non-alcoholic fatty liver disease, as the decreased plasma adiponectin levels, a soluble matrix protein expressed by adipoctyes and hepatocyte, are associated with liver steatosis. Various studies have shown that steatosis is strongly correlated negatively with adiponectin in the patients with HCV infection. The role of adiponectin in hepatitis C virus induced steatosis is still not completely understood, but the relationship between adiponectin low levels and liver steatosis is probably due to the ability of adiponectin to protect hepatocytes from triglyceride accumulation by increasing β-oxidation of free fatty acid and thus decreasing de novo free fatty acid production.

High fat and/or high salt intake during pregnancy alters maternal meta-inflammation and offspring growth and metabolic profiles

A high intake of fat or salt during pregnancy perturbs placental function, alters fetal development, and predisposes offspring to metabolic disease in adult life. Despite its relevance to modern dietary habits, the developmental programming effects of excessive maternal fat and salt, fed in combination, have not been examined. We investigated the effects of moderately high maternal fat and/or salt intake on maternal metainflammation and its consequences on fetal and weanling growth and metabolic profile. Female Sprague–Dawley rats were fed a standard control diet (CD), 4% salt diet (SD), 45% fat diet (HF) or 4% salt/45% fat combined diet (HFSD) 3 weeks prior to and throughout pregnancy and lactation. Plasma and tissue samples were collected at day 18 of pregnancy from mother and fetus, and at postnatal day 24 in weanlings. Markers of adipose tissue inflammation, macrophage infiltration, lipogenesis, nutrient transport, and storage were altered in pregnant dams receiving high‐fat and/or ‐salt diets. This was accompanied by increased fat mass in high‐fat groups and differential hepatic lipid and glucose homeostasis. Offspring of high fat‐fed mothers had reduced fetal weight, displayed catch‐up growth, increased fat mass, and altered metabolic profiles at weaning. Maternal diets high in fat and/or salt affect maternal metabolic parameters, fetal growth and development, metabolic status, and adipoinsular axis in the weanling. Results presented here highlight the importance of diet in expectant mothers or women considering pregnancy. Furthermore, the potential for maternal nutritional intervention strategies may be employed to modify the metabolic disease risk in adult offspring during later life.

We investigated the effects of moderately high maternal fat and/or salt intake on maternal metainflammation and its consequences on fetal and weanling growth and metabolic profile. Maternal diets high in fat and/or salt affect maternal metabolic parameters, fetal growth and development, metabolic status, and adipoinsular axis in the weanling. Results presented here highlight the importance of diet in expectant mothers or women considering pregnancy.

Chemerin concentrations in maternal and fetal compartments: implications for metabolic adaptations to normal human pregnancy

OBJECTIVES

Chemerin, a novel adipocytokine, has been implicated in major metabolic and inflammatory processes. Study aims were to determine whether circulating maternal chemerin concentration (1) differs between pregnant and non-pregnant women, (2) changes as a function of gestational age, and (3) correlates with maternal insulin resistance. In addition, we investigated which compartment, maternal, fetal or placental, is the source of chemerin in maternal circulation.

METHODS

The study included three groups: Non-pregnant (n=18), pregnant women in the first trimester (n=19) and pregnant women in the third trimester (n=33). Chemerin was measured in cord blood and in maternal serum samples taken before and after delivery. Chemerin mRNA expression was evaluated in fetal and human adult tissues.

RESULTS

Chemerin serum concentration was significantly higher in pregnant women in the third trimester than in non-pregnant and pregnant women in the first trimester. Chemerin concentration positively correlated with body mass index (BMI) and insulin resistance. Antenatal chemerin concentration was significantly lower than that during the postpartum period. Neonatal chemerin did not correlate with maternal one. Chemerin mRNA expression was abundant in fetal and adult liver and omental fat, but relatively low in placenta.

CONCLUSIONS

Chemerin is increased during normal gestation and is associated with maternal BMI and insulin resistance. Maternal tissues, possibly liver and adipose tissue, contribute to the increased maternal chemerin concentration.

Pregnancy in obese mice protects selectively against visceral adiposity and is associated with increased adipocyte estrogen signalling

Maternal obesity is linked with increased adverse pregnancy outcomes for both mother and child. The metabolic impact of excessive fat within the context of pregnancy is not fully understood. We used a mouse model of high fat (HF) feeding to induce maternal obesity to identify adipose tissue-mediated mechanisms driving metabolic dysfunction in pregnant and non-pregnant obese mice. As expected, chronic HF-feeding for 12 weeks preceding pregnancy increased peripheral (subcutaneous) and visceral (mesenteric) fat mass. However, unexpectedly at late gestation (E18.5) HF-fed mice exhibited a remarkable normalization of visceral but not peripheral adiposity, with a 53% reduction in non-pregnant visceral fat mass expressed as a proportion of body weight (P<0.001). In contrast, in control animals, pregnancy had no effect on visceral fat mass proportion. Obesity exaggerated glucose intolerance at mid-pregnancy (E14.5). However by E18.5, there were no differences, in glucose tolerance between obese and control mice. Transcriptomic analysis of visceral fat from HF-fed dams at E18.5 revealed reduced expression of genes involved in de novo lipogenesis (diacylglycerol O-acyltransferase 2 - Dgat2) and inflammation (chemokine C-C motif ligand 2 - Ccl2) and upregulation of estrogen receptor α (ERα) compared to HF non pregnant. Attenuation of adipose inflammation was functionally confirmed by a 45% reduction of CD11b⁺CD11c⁺ adipose tissue macrophages (expressed as a proportion of all stromal vascular fraction cells) in HF pregnant compared to HF non pregnant animals (P<0.001). An ERα selective agonist suppressed both de novo lipogenesis and expression of lipogenic genes in adipocytes in vitro. These data show that, in a HF model of maternal obesity, late gestation is associated with amelioration of visceral fat hypertrophy, inflammation and glucose intolerance, and suggest that these effects are mediated in part by elevated visceral adipocyte ERα signaling.

A case of a woman with late-pregnancy-onset DKA who had normal glucose tolerance in the first trimester

Diabetic ketoacidosis (DKA) during pregnancy is a serious complication in both mother and fetus. Most incidences occur during late pregnancy in women with type 1 diabetes mellitus. We report the rare case of a woman with type 1 diabetes mellitus who had normal glucose tolerance during the first trimester but developed DKA during late pregnancy. Although she had initially tested positive for screening of gestational diabetes mellitus during the first trimester, subsequent diagnostic 75-g oral glucose tolerance tests showed normal glucose tolerance. She developed DKA with severe general fatigue in late pregnancy. The patient's general condition improved after treatment for ketoacidosis, and she vaginally delivered a healthy infant at term. The presence of DKA caused by the onset of diabetes should be considered, even if the patient shows normal glucose tolerance during the first trimester.

Energy Balance Regulating Neuropeptides Are Expressed through Pregnancy and Regulated by Interleukin-6 Deficiency in Mouse Placenta

The placenta produces a number of signaling molecules including metabolic and reproductive hormones as well as several inflammatory mediators. Among them, Interleukin-6 (IL-6), a well-known immune and metabolic regulator, acts peripherally modulating metabolic function and centrally increasing energy expenditure and reducing body fat. IL-6 interacts with key hypothalamic neuropeptidergic systems controlling energy homeostasis such as those producing the orexigenic/anabolic: neuropeptide Y (NPY) and agouti-related peptide (AgRP) and anorectic/catabolic neuropeptides: proopiomelanocortin (POMC) and cocaine and amphetamine regulated transcript (CART). Human and rat placenta have been identified as source of these neuropeptides, but their expression and regulation in murine placental tissues remain unknown. Therefore, placental mRNA levels of IL-6, NPY, AgRP, POMC, and CART at different pregnancy stages (gestational days 13, 15, and 18) were analyzed by real time PCR, as were the effect of IL-6 deficiency (IL-6 knockout mice) on their placental expression. Our results showed that placenta-derived neuropeptides were regulated by gestational age and IL-6 throughout the second half of mouse pregnancy. These data suggest that IL-6 may participate in the fine tune control of energy balance during pregnancy by extending its action as a metabolic signal to the main organ at the fetomaternal interface: the placenta.

Supplementation with conjugated linoleic acids extends the adiponectin deficit during early lactation in dairy cows

Decreasing insulin sensitivity (IS) in peripheral tissues allows for partitioning nutrients towards the mammary gland. In dairy cows, extensive lipid mobilization and continued insulin resistance (IR) are typical for early lactation. Adiponectin, an adipokine, promotes IS. Supplementation with conjugated linoleic acids (CLA) in rodents and humans reduces fat mass whereby IR and hyperinsulinemia may occur. In dairy cows, CLA reduce milk fat, whereas body fat, serum free fatty acids and leptin are not affected. We aimed to investigate the effects of CLA supplementation on serum and adipose tissue (AT) adiponectin concentrations in dairy cows during the lactation driven and parity modulated changes of metabolism. High yielding cows (n=33) were allocated on day 1 post partum to either 100 g/day of a CLA mixture or a control fat supplement (CON) until day 182 post partum. Blood and subcutaneous (sc) AT (AT) biopsy samples were collected until day 252 post partum to measure adiponectin. Serum adiponectin decreased from day 21 pre partum reaching a nadir at calving and thereafter increased gradually. The distribution of adiponectin molecular weight forms was neither affected by time, parity nor treatment. Cows receiving CLA had decreased serum adiponectin concentrations whereby primiparous cows responded about 4 weeks earlier than multiparous cows. The time course of adiponectin concentrations in sc AT (corrected for residual blood) was similar to serum concentrations, without differences between CLA and CON. CLA supplementation attenuated the post partum increase of circulating adiponectin thus acting towards prolongation of peripartal IR and drain of nutrients towards the mammary gland.

Management of reproduction and pregnancy complications in maternal obesity: which role for dietary polyphenols?

Obesity is a global and dramatic public health problem; maternal obesity represents one of the main risk factors of infertility and pregnancy complications as it is associated with adverse maternal and offspring outcomes. In the last few years, adipose tissue dysfunction associated with altered adipocytokine secretion has been suggested to play a critical role in all the phases of reproductive process. Obesity is a nutrition-related disorder. In this regard, dietary intervention strategies, such as high intake of fruit and vegetables, have shown significant effects in both preserving health and counteracting obesity-associated diseases. Evidence has been provided that polyphenols, important constituents of plant-derived food, can influence developmental program of oocyte and embryo, as well as pregnancy progression by modulating several cellular pathways. This review will examine the controversial results so far obtained on adipocytokine involvement in fertility impairment and pregnancy complications. Furthermore, the different effects exerted by polyphenols on oocyte, embryo, and pregnancy development will be also taken in account.

Maternal high-fat diets cause insulin resistance through inflammatory changes in fetal adipose tissue

OBJECTIVES

Epidemiological and animal studies have shown that maternal obesity predisposes the offspring to obesity and the metabolic syndrome, possibly via late-onset metabolic programming of the fetus. Little is known, however, about the metabolic effect of maternal obesity on the fetus. This study investigated the effect of a maternal high-fat diet (HFD) on fetal growth and glucose metabolism using a diet-induced obesity mouse model.

STUDY DESIGN

Female mice (6 weeks old; C57BL/6N) were fed either a normal chow diet (NCD, 10 kcal% fat) or an HFD (60 kcal% fat) for 4 weeks before mating and throughout pregnancy. At 17 days of gestation, gene expression of inflammatory markers and adipokines in fetal subcutaneous adipose tissue was analyzed by quantitative real-time polymerase chain reaction.

RESULTS

HFD mice were overweight, glucose intolerant and insulin resistant compared with NCD mice of the same gestational age. Although fetal body weight was not significantly different, fetal plasma glucose and insulin levels were higher in the HFD group than the NCD group. Furthermore, examination of fetal subcutaneous adipose tissue in the HFD group revealed hypertrophy with an increase in the levels of cluster of differentiation-68, chemokine receptor-2 and tumor necrosis factor-α mRNA, but a decrease in the level of glucose transporter-4 mRNA.

CONCLUSION

Maternal HFD causes inflammatory changes in the adipose tissue of offspring.

Association between body weight at weaning and remodeling in the subcutaneous adipose tissue of obese adult mice with undernourishment in utero

Rapid growth in infancy considerably increases the risk of obesity and metabolic disorders in adulthood especially among neonates born small. To investigate the mechanism involved, we developed an animal model of undernourishment in utero by maternal caloric restriction, in which the Z scores of body weight at weaning (19.5 days) positively correlated with parameters of obesity, metabolic disorders, and remodeling of subcutaneous adipose tissue, such as numbers of macrophages in adipose tissue, the ratio of inflammatory M1 to anti-inflammatory M2 macrophages, estimated by gene expression of specific antigens, and the relative ratio of small adipocytes less than 30 μm in diameter, on a high-fat diet at 17 weeks of age. To our knowledge, this is the first report of a possible connection between infantile body weight and adipose tissue remodeling in obesity after undernourishment in utero.

Molecular inflammation and adipose tissue matrix remodeling precede physiological adaptations to pregnancy

Changes in adipose tissue metabolism are central to adaptation of whole body energy homeostasis to pregnancy. To gain insight into the molecular mechanisms supporting tissue remodeling, we have characterized the longitudinal changes of the adipose transcriptome in human pregnancy. Healthy nonobese women recruited pregravid were followed in early (8-12 wk) and in late (36-38 wk) pregnancy. Adipose tissue biopsies were obtained in the fasting state from the gluteal depot. The adipose transcriptome was examined via whole genome DNA microarray. Expression of immune-related genes and extracellular matrix components was measured using real-time RT-PCR. Adipose mass, adipocyte size, and cell number increased in late pregnancy compared with pregravid measurements (P < 0.001) but remained unchanged in early pregnancy. The adipose transcriptome evolved during pregnancy with 10-15% of genes being differently expressed compared with pregravid. Functional gene cluster analysis revealed that the early molecular changes affected immune responses, angiogenesis, matrix remodeling, and lipid biosynthesis. Increased expression of macrophage markers (CD68, CD14, and the mannose-6 phosphate receptor) emphasized the recruitment of the immune network in both early and late pregnancy. The TLR4/NF-κB signaling pathway was enhanced specifically in relation to inflammatory adipokines and chemokines genes. We conclude that early recruitment of metabolic and immune molecular networks precedes the appearance of pregnancy-related physiological changes in adipose tissue. This biphasic pattern suggests that physiological inflammation is an early step preceding the development of insulin resistance, which peaks in late pregnancy.