Magnus Strand

Intra-adipose sex steroid metabolism and body fat distribution in idiopathic human obesity

Objective  Causes of visceral fat accumulation include glucocorticoid excess or decreased oestrogen/androgen ratio either in plasma or within adipose tissue. In obese subjects, the intra‐adipose cortisol‐generating enzyme 11β‐hydroxysteroid dehydrogenase type 1 (11β‐HSD1) is increased, but information on sex steroid signalling is sparse. We aimed to test associations between body fat or fat distribution and mRNA transcript levels for androgen and oestrogen receptors and for enzymes metabolizing sex steroids in adipose tissue.

Galectin-1 influences trophoblast immune evasion and emerges as a predictive factor for the outcome of pregnancy

Galectin-1 (gal-1) is expressed at the feto-maternal interface and plays a role in regulating the maternal immune response against placental alloantigens, contributing to pregnancy maintenance. Both decidua and placenta contribute to gal-1 expression and may be important for the maternal immune regulation. The expression of gal-1 within the placenta is considered relevant to cell-adhesion and invasion of trophoblasts, but the role of gal-1 in the immune evasion machinery exhibited by trophoblast cells remains to be elucidated. In this study, we analyzed gal-1 expression in preimplantation human embryos and first-trimester decidua-placenta specimens and serum gal-1 levels to investigate the physiological role played by this lectin during pregnancy. The effect on human leukocyte antigen G (HLA-G) expression in response to stimulation or silencing of gal-1 was also determined in the human invasive, proliferative extravillous cytotrophoblast 65 (HIPEC65) cell line. Compared with normal pregnant women, circulating gal-1 levels were significantly decreased in patients who subsequently suffered a miscarriage. Human embryos undergoing preimplantation development expressed gal-1 on the trophectoderm and inner cell mass. Furthermore, our in vitro experiments showed that exogenous gal-1 positively regulated the membrane-bound HLA-G isoforms (HLA-G1 and G2) in HIPEC65 cells, whereas endogenous gal-1 also induced expression of the soluble isoforms (HLA-G5 and -G6). Our results suggest that gal-1 plays a key role in pregnancy maternal immune regulation by modulating HLA-G expression on trophoblast cells. Circulating gal-1 levels could serve as a predictive factor for pregnancy success in early human gestation.

Maternal Foxp3 Expressing CD4+ CD25+ and CD4+ CD25− Regulatory T-Cell Populations are Enriched in Human Early Normal Pregnancy Decidua: A Phenotypic Study of Paired Decidual and Peripheral Blood Samples

Citation Dimova T, Nagaeva O, Stenqvist A‐Christin, Hedlund M, Kjellberg L, Strand M, Dehlin E, Mincheva‐Nilsson L. Maternal Foxp3 Expressing CD4+ CD25+ and CD4+ CD25− Regulatory T‐Cell Populations are Enriched in Human Early Normal Pregnancy Decidua: A Phenotypic Study of Paired Decidual and Peripheral Blood Samples. Am J Reprod Immunol 2011; 66 (Suppl. 1): 44–56

Tissue-Specific Increases in 11β-Hydroxysteroid Dehydrogenase Type 1 in Normal Weight Postmenopausal Women

With age and menopause there is a shift in adipose distribution from gluteo-femoral to abdominal depots in women. Associated with this redistribution of fat are increased risks of type 2 diabetes and cardiovascular disease. Glucocorticoids influence body composition, and 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) which converts inert cortisone to active cortisol is a putative key mediator of metabolic complications in obesity. Increased 11βHSD1 in adipose tissue may contribute to postmenopausal central obesity. We hypothesized that tissue-specific 11βHSD1 gene expression and activity are up-regulated in the older, postmenopausal women compared to young, premenopausal women. Twenty-three pre- and 23 postmenopausal, healthy, normal weight women were recruited. The participants underwent a urine collection, a subcutaneous adipose tissue biopsy and the hepatic 11βHSD1 activity was estimated by the serum cortisol response after an oral dose of cortisone. Urinary (5α-tetrahydrocortisol+5β-tetrahydrocortisol)/tetrahydrocortisone ratios were higher in postmenopausal women versus premenopausal women in luteal phase (P<0.05), indicating an increased whole-body 11βHSD1 activity. Postmenopausal women had higher 11βHSD1 gene expression in subcutaneous fat (P<0.05). Hepatic first pass conversion of oral cortisone to cortisol was also increased in postmenopausal women versus premenopausal women in follicular phase of the menstrual cycle (P<0.01, at 30 min post cortisone ingestion), suggesting higher hepatic 11βHSD1 activity. In conclusion, our results indicate that postmenopausal normal weight women have increased 11βHSD1 activity in adipose tissue and liver. This may contribute to metabolic dysfunctions with menopause and ageing in women.

17β-estradiol and enriched environment accelerate cognitive recovery after focal brain ischemia

Cognitive impairments, including spatial memory and learning deficiencies, are common after ischemic stroke. Estrogen substitution improves cognitive functions in post‐menopausal women and ovariectomized rodents, partially through induction of neuroplasticity in the hippocampal formation. Post‐ischemic housing of male rats in an enriched environment (EE) improves functional outcome, without changing infarct volume. We hypothesized that 17β‐estradiol combined with an EE would accelerate cognitive recovery after focal brain ischemia in ovariectomized rats and that recovery would be related to altered expression of nerve growth factor‐induced gene (NGFI)‐A in the hippocampus. 17β‐estradiol or placebo pellets were implanted 6 h after transient middle cerebral artery occlusion. Two days later, rats were placed in an EE or a deprived environment (DE) for 6 weeks. At 5 weeks after middle cerebral artery occlusion, 17β‐estradiol‐treated rats housed in an EE showed improvements in cognitive function (i.e. shorter latency and path in the Morris water maze task) compared with placebo‐treated animals housed in an EE. Furthermore, beneficial effects on latency and path were observed when comparing EE‐housed vs. DE‐housed 17β‐estradiol‐treated rats. When comparing 17β‐estradiol‐treated EE‐housed rats vs. placebo‐treated DE‐housed rats, pronounced effects on latency and path were observed. Infarct volumes did not differ between groups. 17β‐estradiol‐treated EE‐housed rats had significantly higher NGFI‐A mRNA expression bilaterally in the cornu ammonis 1 region and in the ipsilateral dentate gyrus of the hippocampus, compared with placebo‐treated EE‐housed rats. In conclusion, 17β‐estradiol treatment combined with an EE improved recovery of cognitive function after experimental brain ischemia, putatively through the upregulation of NGFI‐A in hippocampal subregions.

Polymorphisms at the Osteoprotegerin and Interleukin-6 Genes in Relation to First-Ever Stroke

Background: Arterial calcification and osteoporosis often coexist, especially in postmenopausal women. Osteoporosis associates with a substantially increased risk of stroke in elderly women, suggesting that impaired estrogen signaling may link stroke and osteoporosis. Osteoprotegerin (OPG, TNFRSF11B) and interleukin-6 (IL-6, IL6) are putative target genes for estrogen signaling and have been implicated in both cardiovascular diseases and osteoporosis. We hypothesized that specific polymorphisms in these genes may be associated with increased risk of ischemic stroke or intracerebral hemorrhage (ICH). Methods: We performed a population-based prospective nested case-control study, in which the relationships between polymorphisms (OPG-1181G/C, OPG-950T/C and IL6-174G/C) and ischemic stroke and ICH were examined. Definitive first-ever stroke events (n = 388), i.e. ischemic stroke (n = 320), ICH (n = 61) and unspecified stroke (n = 7) cases, and controls without cardiovascular disease (n = 773), matched for age, sex and geographical region were studied. Univariate and multivariate models using conditional logistic regression, which included traditional risk factors, were used to test for association. Results: Carriers of the OPG-1181C/C genotype had a significantly (p = 0.018) increased risk of ICH (OR, 2.69; 95% CI, 1.19–6.12) in the univariate analysis. After adjustments (hypertension, diabetes, BMI and triglycerides), this genotype remained significantly (p = 0.005) associated with ICH (OR, 6.04; 95% CI, 1.71–21.29). By contrast, no correlations were found between this genotype and ischemic stroke, nor between the OPG-950T/C or IL6-174G/C polymorphisms and stroke subtypes. Conclusions: In this population, the OPG-1181C/C genotype associates with first-ever ICH, implying that alterations in OPG-mediated signaling in the vasculature may be involved in the pathophysiology of this disease.

Estrogen Receptor Alpha Gene Polymorphisms and First-Ever Intracerebral Hemorrhage.

Background: Signaling through estrogen receptor alpha (ERα) regulates vasodilatation and atherogenesis. Since hypertension and atherosclerosis are major mechanisms in stroke development, we hypothesized that genetic variants of the ERα gene (ESR1) are determinants of future ischemic stroke or intracerebral hemorrhage (ICH). Methods: In a population-based prospective nested case-control study, the relationships between ESR1 polymorphisms (c.454–397T>C and c.454–351A>G) and ischemic stroke and ICH were examined in univariate and multivariate models using conditional logistic regression, which included established risk factors.Definitive first-ever stroke events (n = 388), including ischemic stroke (n = 320), ICH (n = 61), and unspecified stroke (n = 7) cases, and controls without cardiovascular disease (n = 773), matched for age, sex, and geographical region were included. Results: Carriers of the c.454–397T/T genotype had a significantly (p = 0.017) increased risk of ICH (OR 2.31, 95% CI 1.16–4.60) in a univariate analysis. This association persisted (OR 3.94, 95% CI 1.54–10.03), after adjustment for stroke risk determinants. Carriers of c.454–397T/T or c.454–397T/C genotypeshad significantly (p = 0.002 and p = 0.004, respectively) higher mean systolic blood pressure (SBP), than carriers of c.454–397C/C, and a similar relationship was observed for diastolic blood pressure (DBP). The combinations of c.454–397T/T genotype and hypertension (OR 21.46, 95% CI 5.20–88.51), or high SBP (OR 18.17, 95% CI 4.91–67.31) or DBP (OR 11.94, 95% CI 3.75–38.03), were strongly associated with increased risk of ICH. Conclusions: In this population,the c.454–397T/T genotype associates with first-ever ICH, particularly in combination with hypertension. This implies that alterations in ERα-mediated signaling may be involved in the pathophysiology of this disease, with a putative impact on primary prevention.

Abstract C140: RNA expression patterns in serum microvesicles from patients with glioblastoma multiforme and ovarian cancer.

Background: Recent studies have shown that RNA isolated from exosomes and other microvesicles (exoRNA) contain diagnostically relevant transcripts of tumor origin. In this study we sought to identify specific biomarkers of glioblastoma multiforme (GBM) and malignant ovarian cancer in the ribonucleic acid fraction extracted from microvesicles (exoRNA) isolated from the serum of affected patients. Methods: All samples were collected following informed consent in accordance with the appropriate protocols approved by the MGH Institutional Review Board (GBM) and the Umea University ethics committee (ovarian tumors). Patients with primary GBM (N=9), normal controls (N=7); and pathologically proven benign (N=16), borderline (N=19), and malignant (N=29, stage I-IV, grade 1–3) neoplastic transformation of the ovaries were included. ExoRNA isolated from patient serum was amplified and analyzed by microarray analysis on Agilent 4×44K arrays (GBM) and Agilent 8×60K arrays (ovarian tumors). Differential expressions between control and GBM samples were validated by qRT-PCR in a separate set of samples (N=10 in both groups). Results: Array analysis of the amplified exoRNA yielded significant signals from at least 10,000 genes on the array for all samples. The expression profiles of the exoRNA from GBM patients were shown to be different from those of normal healthy volunteers. The most significant expression differences observed in the array analysis pertained to down-regulated genes (121 genes >2-fold down) in the GBM patient exoRNA, which was validated by qRT-PCR on several genes. Gene ontology analysis of the down-regulated genes indicated these are primarily mRNAs coding for ribosomal proteins and other genes related to ribosome production. Supervised analysis showed no significant differential gene expression between the benign, borderline, and malignant ovarian tumors. However, unsupervised Consensus Clustering yielded a clear segregation of the patients into two new groups (100% resampling consensus for 61 samples). Gene Set Enrichment Analysis (GSEA) showed a strong association of one of the two groups with genes linked to translation initiation (FDR q-value 0.04), and mRNA processing (FDR q-value 0.032). GSEA also confirmed a strong overlap of the genes separating the ovarian cancer samples into two groups with those discriminating GBM from healthy control individuals. Conclusions: Microvesicle isolated RNA from patients with GBM is significantly different from that of normal control individuals. The same genes support a binary classification of ovarian tumors suggesting that common biological processes may be in effect for these different tumor types. The common signature is hallmarked by messenger RNAs coding for ribosome production, which are significantly downregulated in GBM exoRNA and in one of two novel subgroups of ovarian tumors. While the biological role of this signature remains to be elucidated, we conclude that exosomal RNA expression profiling has the potential to serve as a clinically relevant diagnostic source of information about the biology, malignancy, and state of tumors. This underlines the diagnostic potential of exosomes not only in early diagnosis, but also in directing therapies, evaluating response and in situations where biopsy samples are difficult to access. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C140.

Contents Vol. 24, 2007

483 Third International Stroke Summit Wuhan, China, November 1–3, 2007 Chairpersons: Liu, X. (Nanjing); Kaste, M. (Helsinki); Zhang, S.; Zhang, J. (Wuhan); Chopp, M. (Detroit, Mich.); Li, C.; Chen, G. (Wuhan); Xu, G. (Nanjing) (available online only)