Publications
193 results found
Bouatia-Naji N, Bonnefond A, Cavalcanti-Proenca C, et al., 2009, A variant near MTNR1B is associated with increased fasting plasma glucose levels and type 2 diabetes risk, Nat Genet, Vol: 41, Pages: 89-94, ISSN: 1546-1718
In genome-wide association (GWA) data from 2,151 nondiabetic French subjects, we identified rs1387153, near MTNR1B (which encodes the melatonin receptor 2 (MT2)), as a modulator of fasting plasma glucose (FPG; P = 1.3 x 10(-7)). In European populations, the rs1387153 T allele is associated with increased FPG (beta = 0.06 mmol/l, P = 7.6 x 10(-29), N = 16,094), type 2 diabetes (T2D) risk (odds ratio (OR) = 1.15, 95% CI = 1.08-1.22, P = 6.3 x 10(-5), cases N = 6,332) and risk of developing hyperglycemia or diabetes over a 9-year period (hazard ratio (HR) = 1.20, 95% CI = 1.06-1.36, P = 0.005, incident cases N = 515). RT-PCR analyses confirm the presence of MT2 transcripts in neural tissues and show MT2 expression in human pancreatic islets and beta cells. Our data suggest a possible link between circadian rhythm regulation and glucose homeostasis through the melatonin signaling pathway.
Al-Janabi I, Arranz MJ, Blakemore AI, et al., 2009, Association study of serotonergic gene variants with antipsychotic-induced adverse reactions, Psychiatr Genet, Vol: 19, Pages: 305-311, ISSN: 1473-5873
INTRODUCTION: The products of the serotonin receptor genes are important targets for conventional and atypical antipsychotics, and may be relevant for antipsychotic activity and associated adverse reactions. It has been shown that the high potency at 5-HT2 receptors may also be associated with the production of moderate extrapyramidal side effects (EPS). In addition, serotonin neurotransmitter systems in the central nervous system play an important role in eating behaviours, and are involved in the symptomatology related to the metabolic syndrome, including obesity, diabetes and hyperlipidemia. MATERIALS AND METHODS: This study was designed to investigate the hypothesis that serotonin pathway genes play a part in mediating antipsychotic-induced adverse reactions, including EPS, tardive dyskinesia, obesity and diabetes. Polymorphisms in the 5-HT2A (102 (T/C), His452Tyr), 5-HT2C (Cys23Ser, -759 (C/T), -995 (G/A), TPH2 (-366 (C/T), -8933 (A/G) and 5-HTT (LPR, -15370 (A/G)) genes were investigated in a cohort of 427 US Caucasian patients undergoing antipsychotic treatment, using automated genotyping techniques. RESULTS: 5-HTT (LPR) and 5-HT2A (102 (T/C) polymorphisms were found to be associated with BMI (P=0.05 and 0.005, respectively). The genotype distribution of the TPH2-366 (T/C) polymorphism was found to be significantly associated with the presence of diabetes (P=0.01). A trend towards an association (P=0.07) between the 5-HT2C Cys23Ser polymorphism and tardive dyskinesia was found when age, duration of treatment, dose and sex were considered. Genotype distributions of the 5-HT2C -995 (G/A), 5-HT2C -759 (C/T) and 5-HT2A His452Tyr polymorphisms differed among patients presenting EPS and those without (P=0.08, 0.06 and 0.08, respectively). No other statistically significant associations were observed. CONCLUSION: Serotonergic polymorphism may play a moderate role in the development of side effects associated with antipsychotic treatment.
de Smith AJ, Purmann C, Walters RG, et al., 2009, A deletion of the HBII-85 class of small nucleolar RNAs (snoRNAs) is associated with hyperphagia, obesity and hypogonadism, Hum Mol Genet, Vol: 18, Pages: 3257-3265, ISSN: 1460-2083
Genetic studies in patients with severe early-onset obesity have provided insights into the molecular and physiological pathways that regulate body weight in humans. We report a 19-year-old male with hyperphagia and severe obesity, mild learning difficulties and hypogonadism, in whom diagnostic tests for Prader-Willi syndrome (PWS) had been negative. We carried out detailed clinical and metabolic phenotyping of this patient and investigated the genetic basis of this obesity syndrome using Agilent 185 k array comparative genomic hybridization (aCGH) and Affymetrix 6.0 genotyping arrays. The identified deletion was validated using multiplex ligation-dependent probe amplification and long-range PCR, followed by breakpoint sequencing which enabled precise localization of the deletion. We identified a approximately 187 kb microdeletion at chromosome 15q11-13 that encompasses non-coding small nucleolar RNAs (including HBII-85 snoRNAs) which were not expressed in peripheral lymphocytes from the patient. Characterization of the clinical phenotype revealed increased ad libitum food intake, normal basal metabolic rate when adjusted for fat-free mass, partial hypogonadotropic hypogonadism and growth failure. We have identified a novel deletion on chromosome 15q11-13 in an individual with hyperphagia, obesity, hypogonadism and other features associated with PWS, which is normally caused by deficiency of several paternally expressed imprinted transcripts within chromosome 15q11-13, a region that includes multiple protein-coding genes as well as several non-coding snoRNAs. These findings provide direct evidence for the role of a particular family of non-coding RNAs, the HBII-85 snoRNA cluster, in human energy homeostasis, growth and reproduction.
de Smith A, Walters RG, Coin LJM, et al., 2008, Alu elements implicated in the generation of 9/20 CNV deletions investigated by breakpoint sequencing, British Human Genetics Conference, Publisher: B M J PUBLISHING GROUP, Pages: S90-S90, ISSN: 0022-2593
Knight SC, English NR, Blakemore AI, 2008, Interactions between dendritic cells, probiotic bacteria and the adipokine leptin., Proc Nutr Soc, Vol: 67, Pages: E15-E15, ISSN: 0029-6651
de Smith AJ, Walters RG, Coin LJ, et al., 2008, Small deletion variants have stable breakpoints commonly associated with alu elements, PLoS One, Vol: 3, ISSN: 1932-6203
Copy number variants (CNVs) contribute significantly to human genomic variation, with over 5000 loci reported, covering more than 18% of the euchromatic human genome. Little is known, however, about the origin and stability of variants of different size and complexity. We investigated the breakpoints of 20 small, common deletions, representing a subset of those originally identified by array CGH, using Agilent microarrays, in 50 healthy French Caucasian subjects. By sequencing PCR products amplified using primers designed to span the deleted regions, we determined the exact size and genomic position of the deletions in all affected samples. For each deletion studied, all individuals carrying the deletion share identical upstream and downstream breakpoints at the sequence level, suggesting that the deletion event occurred just once and later became common in the population. This is supported by linkage disequilibrium (LD) analysis, which has revealed that most of the deletions studied are in moderate to strong LD with surrounding SNPs, and have conserved long-range haplotypes. Analysis of the sequences flanking the deletion breakpoints revealed an enrichment of microhomology at the breakpoint junctions. More significantly, we found an enrichment of Alu repeat elements, the overwhelming majority of which intersected deletion breakpoints at their poly-A tails. We found no enrichment of LINE elements or segmental duplications, in contrast to other reports. Sequence analysis revealed enrichment of a conserved motif in the sequences surrounding the deletion breakpoints, although whether this motif has any mechanistic role in the formation of some deletions has yet to be determined. Considered together with existing information on more complex inherited variant regions, and reports of de novo variants associated with autism, these data support the presence of different subgroups of CNV in the genome which may have originated through different mechanisms.
de Smith AJ, Walters RG, Froguel P, et al., 2008, Human genes involved in copy number variation: mechanisms of origin, functional effects and implications for disease, Cytogenet Genome Res, Vol: 123, Pages: 17-26, ISSN: 1424-859X
Copy number variants (CNVs) overlap over 7000 genes, many of which are pivotal in biological pathways. The implications of this are profound, with consequences for evolutionary studies, population genetics, gene function and human phenotype, including elucidation of genetic susceptibility to major common diseases, the heritability of which has thus far defied full explanation. Even though this research is still in its infancy, CNVs have already been associated with a number of monogenic, syndromic and complex diseases: the development of high throughput and high resolution techniques for CNV screening is likely to bring further new insights into the contribution of copy number variation to common diseases. Amongst genes overlapped by CNVs, significant enrichments for certain gene ontology categories have been identified, including those related to immune responses and interactions with the environment. Genes in both of these categories are thought to be important in evolutionary adaptation and to be particular targets of natural selection. Thus, a full appreciation of copy number variation may be important for our understanding of human evolution.
Froguel P, Blakemore AI, 2008, The power of the extreme in elucidating obesity, N Engl J Med, Vol: 359, Pages: 891-893, ISSN: 1533-4406
Blakemore AI, Froguel P, 2008, Is obesity our genetic legacy?, J Clin Endocrinol Metab, Vol: 93, Pages: S51-S56, ISSN: 0021-972X
CONTEXT: To design rational management regimes and identify novel therapeutic targets, it is essential to understand the biological drivers of the current epidemic of obesity. This review describes our current knowledge of genetic factors in obesity, drawing functional parallels in the underlying neuroendocrine mechanisms and suggesting promising new directions for research. EVIDENCE ACQUISITION: Published literature, addressing both the current knowledge of genetics of monogenic and syndromic forms of extreme obesity, and the emerging literature on genetic factors associated with more common forms of obesity are analyzed. EVIDENCE SYNTHESIS: The current genetic evidence in obesity underlines the importance of neuroendocrine mechanisms of appetite regulation. Monogenic forms of disease explain 6% of children with extreme obesity, having hyperphagia associated with defects in the leptin-melanocortin pathway, as a central feature. Candidate gene association studies indicate that more subtle variations of the same genes also contribute to common forms of obesity. Well-powered genome-wide association studies recently identified FTO as a strong contributor to both childhood and adult obesity, demonstrating the power of such hypothesis-free analysis to provide new insights into the underlying pathogenic mechanisms of a common complex disease. CONCLUSIONS: Although there has been some very heartening recent progress in elucidating genetic mechanisms underlying obesity, we are still a long way from explaining the high heritability of adiposity. Investigations of different forms of variation, such as copy number polymorphism, may extend our understanding of this condition.
Blakemore A, de Smith AJ, Tsalenko A, et al., 2007, Interpretation of array CGH data: adding to the growing list of copy number variants in healthy subjects, British Human Genetics Conference, Publisher: B M J PUBLISHING GROUP, Pages: S31-S31, ISSN: 0022-2593
Bisoni L, Studd JB, Buch M, et al., 2007, Looking for predictors of aCGH quality: a retrospective study of the outcome of 38 Agilent 185K oligonucleotide arrays, British Human Genetics Conference, Publisher: B M J PUBLISHING GROUP, Pages: S112-S112, ISSN: 0022-2593
Fairbrother UL, Tanko LB, Walley AJ, et al., 2007, Leptin receptor genotype at Gln223Arg is associated with body composition, BMD, and vertebral fracture in postmenopausal Danish women, J Bone Miner Res, Vol: 22, Pages: 544-550, ISSN: 0884-0431
Leptin is emerging as a key regulator of bone remodeling. In a population-based study of 1306 postmenopausal Danish women, nonsynonymous LEPR SNPs were associated with risk of adiposity, BMD, and vertebral fracture. Smoking exacerbates this LEPR-associated fracture risk. INTRODUCTION: Nonsynonymous single nucleotide polymorphisms (SNPs) in the human LEPR gene have been associated with adiposity in a number of studies, but there have been no large-scale studies of their implications for BMD and osteoporotic fracture risk in postmenopausal women. MATERIALS AND METHODS: We carried out a population-based study of 1430 women. Three well-known nonsynonymous leptin receptor (LEPR) SNPs (Lys109Arg, Gln223Arg, and Lys656Asn) were genotyped for qualitative and quantitative association analysis. Phenotype characteristics of main interest were DXA measures of body fat and lean tissue mass, BMD, and radiographic vertebral fractures. RESULTS: Gln223Arg associated with risk of vertebral fracture (overall OR = 1.76; OR in smokers = 2.31; p = 0.0004), in addition to BMD of the femoral neck and total hip (p = 0.036 and 0.008, respectively). Heterozygote carriers showed lower BMD at both sites. Gln223Arg was also associated with adiposity (p = 0.001 for total fat mass). For adiposity, the at-risk allele was G (resulting in an arginine at position 223). CONCLUSIONS: Variation in LEPR seemed to contribute to the variation in BMD and fracture risk in Danish postmenopausal women; the heterozygous genotype was associated with increased risk of manifest osteoporosis. Further studies are needed to replicate these data and to clarify the mechanisms involved.
de Smith AJ, Tsalenko A, Sampas N, et al., 2007, Array CGH analysis of copy number variation identifies 1284 new genes variant in healthy white males: implications for association studies of complex diseases, Hum Mol Genet, Vol: 16, Pages: 2783-2794, ISSN: 0964-6906
The discovery of copy number variation in healthy individuals is far from complete, and owing to the resolution of detection systems used, the majority of loci reported so far are relatively large ( approximately 65%>10 kb). Applying a two-stage high-resolution array comparative genomic hybridization approach to analyse 50 healthy Caucasian males from northern France, we discovered 2208 copy number variants (CNVs) detected by more than one consecutive probe. These clustered into 1469 CNV regions (CNVRs), of which 721 are thought to be novel. The majority of these are small (median size 4.4 kb) and most have common boundaries, with a coefficient of variation less than 0.1 for 83% of endpoints in those observed in multiple samples. Only 6% of the CNVRs analysed showed evidence of both copy number losses and gains at the same site. A further 6089 variants were detected by single probes: 48% of these were observed in more than one individual. In total, 2570 genes were seen to intersect variants: 1284 in novel loci. Genes involved in differentiation and development were significantly over-represented and approximately half of the genes identified feature in the Online Mendelian Inheritance in Man database. The biological importance of many genes affected, along with the well-conserved nature of the majority of the CNVs, suggests that they could have important implications for phenotype and, thus, be useful for association studies of complex diseases.
Fanciulli M, Norsworthy PJ, Petretto E, et al., 2007, FCGR3B copy number variation is associated with susceptibility to systemic, but not organ-specific, autoimmunity, Nat Genet, Vol: 39, Pages: 721-723, ISSN: 1061-4036
Naturally occurring variation in gene copy number is increasingly recognized as a heritable source of susceptibility to genetically complex diseases. Here we report strong association between FCGR3B copy number and risk of systemic lupus erythematosus (P = 2.7 x 10(-8)), microscopic polyangiitis (P = 2.9 x 10(-4)) and Wegener's granulomatosis in two independent cohorts from the UK (P = 3 x 10(-3)) and France (P = 1.1 x 10(-4)). We did not observe this association in the organ-specific Graves' disease or Addison's disease. Our findings suggest that low FCGR3B copy number, and in particular complete FCGR3B deficiency, has a key role in the development of systemic autoimmunity.
Walley AJ, Blakemore AI, Froguel P, 2006, Genetics of obesity and the prediction of risk for health, Hum Mol Genet, Vol: 15 Spec No 2, Pages: R124-R130, ISSN: 0964-6906
Obesity has always existed in human populations, but until very recently was comparatively rare. The availability of abundant, energy-rich processed foods in the last few decades has, however, resulted in a sharp rise in the prevalence of obesity in westernized countries. Although it is the obesogenic environment that has resulted in this major healthcare problem, it is acting by revealing a sub-population with a pre-existing genetic predisposition to excess adiposity. There is substantial evidence for the heritability of obesity, and research in both rare and common forms of obesity has identified genes with significant roles in its aetiology. Application of this understanding to patient care has been slower. Until very recently, the health risks of obesity were thought to be well understood, with a straightforward correlation between increasing obesity and increasing risk of health problems such as type 2 diabetes, coronary heart disease, hypertension, arthritis and cancer. It is becoming clear, however, that the location of fat deposition, variation in the secretion of adipokines and other factors govern whether a particular obese person develops such complications. Prediction of the health risks of obesity for individual patients is not straightforward, but continuing advances in understanding of genetic factors influencing obesity risk and improved diagnostic technologies mean that the future for such prediction is looking increasingly bright.
English NR, Blakemore AIF, Knight SC, 2005, Differential modulation of expression of leptin receptors on dendritic cells (DC) by pro- and anti-inflammatory stimuli, Publisher: BLACKWELL PUBLISHING, Pages: 101-101, ISSN: 0019-2805
Fairbrother U, Walley AJ, Boyle C, et al., 2005, Coding SNPs in the human leptin receptor gene contribute to severe obesity in French Caucasian adults, British Human Genetics Conference, Publisher: B M J PUBLISHING GROUP, Pages: S116-S116, ISSN: 0022-2593
Khalil MS, El Nahas AM, Blakemore AI, 2005, Transforming growth factor-beta1 SNPs: genetic and phenotypic correlations in progressive kidney insufficiency, Nephron Exp Nephrol, Vol: 101, Pages: e31-e41, ISSN: 1660-2129
Associations have been described between polymorphisms of cytokine and growth factor genes and susceptibility to, or progression of, an increasing number of diseases. TGF-beta1 plays an important role in the pathogenesis of experimental and clinical glomerulosclerosis and tubulointerstitial fibrosis. In this study, single nucleotide polymorphisms (SNPs) in the TGFbeta1 gene were investigated as possible markers for the progression of chronic kidney failure (CKF). 145 Caucasian patients with CKF were screened for four TGFbeta1 SNPs: T-509C in the promoter region; Arg25Pro and Leu10Pro in exon 1 and Thr263Ile in exon 5. There were significant differences between CKF patients and controls in allele frequencies of two of the SNPs, Leu10Pro (p = 0.038) and C-509T (p = 0.02) and in haplotype distributions (p = 0.0175), indicating an association with susceptibility to CKF. We also observed a significant association between progression of CKF and homozygosity for Arg25 (odds ratio 3.77, 95% confidence interval 1.57-9.04, p = 0.002). Homozygosity for Arg25 was also associated with severity of proteinuria at diagnosis (p = 0.038), plasma TGF-beta1 protein levels (p = 0.01), and severity of glomerulosclerosis (p = 0.04). Homozygosity for -509T was associated with severity of proteinuria at diagnosis (p = 0.0017), level of renal tubular TGF-beta1 immunostaining (p = 0.0006) and with severity of renal interstitial inflammatory cellular infiltration (p = 0.01). Tubular TGF-beta1 immunostaining was significantly higher in biopsies with inflammatory cellular infiltration compared those without inflammation (p = 0.0048). There was a significant difference in haplotype distributions between CKF patients with progressive, as opposed to non-progressive disease (p = 0.0484). TGFbeta1 SNPs may be useful prognostic indicators for the progression of CKF.
Linjawi S, Li TC, Laird S, et al., 2005, Interleukin-1 receptor antagonist and interleukin-1 beta polymorphisms in women with recurrent miscarriage, Fertil Steril, Vol: 83, Pages: 1549-1552, ISSN: 1556-5653
Genotypes and allele distributions for the interleukin (IL)-1beta -511 C/T and the IL-1 receptor antagonist gene intron 2 tandem repeat polymorphisms were compared in 206 women with recurrent miscarriage and a control population. No significant differences were observed between the distributions of IL-1beta or IL-1 receptor antagonist gene alleles in either the recurrent miscarriage group as a whole or when divided according to the cause of recurrent miscarriage compared with controls, which suggests that variation in the IL-1 receptor antagonist gene and IL-1beta genes individually does not play a role in susceptibility to recurrent miscarriage.
Linjawi S, Li TC, Tuckerman EM, et al., 2004, Expression of interleukin-11 receptor alpha and interleukin-11 protein in the endometrium of normal fertile women and women with recurrent miscarriage, J Reprod Immunol, Vol: 64, Pages: 145-155, ISSN: 0165-0378
Interleukin-11 (IL-11) is a member of the IL-6 family of cytokines. Previous studies have suggested that IL-11 may play a role in human endometrial function. In this study, we have used immunocytochemistry to compare endometrial IL-11Ralpha and IL-11 expression in precisely timed peri-implantation biopsies from 9 normal fertile women and 16 recurrent miscarriage (RM) women. Immunocytochemistry was semi-quantified by obtaining an H-score value, which showed increased expression of both IL-11 and IL-11Ralpha in epithelial cells compared to stromal cells in all biopsies. There was a significant (P<0.01) reduction in epithelial cell IL-11, but not stromal cell IL-11, expression in endometrium from RM women compared to normal fertile women. There were no significant differences in expression of IL-11Ralpha protein in both stromal and epithelial cells in endometrium from the two groups of women. This work shows the presence of IL-11 and IL-11Ralpha within the endometrium of RM women during the peri-implantation period. The decreased expression of IL-11 in epithelial endometrium in RM women suggests that this cytokine may play a role in preventing miscarriage.
Capper ER, Maskill JK, Gordon C, et al., 2004, Interleukin (IL)-10, IL-1ra and IL-12 profiles in active and quiescent systemic lupus erythematosus: could longitudinal studies reveal patient subgroups of differing pathology?, Clin Exp Immunol, Vol: 138, Pages: 348-356, ISSN: 0009-9104
Several cytokines have been implicated individually in the pathogenesis of systemic lupus erythematosus (SLE) and some, including interleukin (IL)-10, IL-12 and IL-1ra are raised during flares of disease activity. Few studies have been directed at examining the interactions between these cytokines and how their combined profile relates to disease activity. We have examined serum levels of IL-10, IL-12 and IL-1ra in a cohort of SLE patients obtained from the Queen Elizabeth Hospital, Birmingham in cross-sectional and, in a smaller group, longitudinal analyses. In the cross-sectional study, there were significant correlations between levels of the three cytokines. There were also significant correlations between levels of each cytokine and measures of disease activity. IL-10 levels correlated with ESR, anti-dsDNA antibody titres and C3D, IL-12 levels with anti-dsDNA antibody titres and IL-1ra levels with ESR, anti-dsDNA antibody titres and C3D. IL-1ra levels also correlated with CRP. Circulating IL-10 and IL-1ra levels were higher in patients with SLE than in normal controls, although in this study group they did not reach significance. Circulating IL-12 levels were, however, significantly higher in SLE compared to controls. This was true both in patients with active disease and those sampled during a quiescent phase. These data add to the evidence that cytokines such as IL-10, IL-12 and IL-1ra are important in SLE pathogenesis. In a retrospective study of serial serum samples from seven patients, we found two patients whose cytokine profile was very different from the rest of the group. In most patients normalized IL-10, IL-12 and IL-1ra levels mirrored BILAG scores closely, but in these two patients, IL-10, IL-12 and IL-1ra levels did not fluctuate with disease activity. It is possible that there is a subgroup of SLE patients whose cytokine profile could be an important indicator of their pathology. In order to confirm this and determine the frequency of such patien
Quinton ND, Meechan DW, Brown K, et al., 2004, Single nucleotide polymorphisms in the leptin receptor gene: studies in anorexia nervosa, Psychiatr Genet, Vol: 14, Pages: 191-194, ISSN: 0955-8829
Anorexia nervosa is an eating disorder of unknown aetiology. There is significant evidence for a genetic component in the pathogenesis of this disorder. A region on chromosome 1 has been identified as a susceptibility locus. The leptin receptor has been mapped to a similar region, further upstream of this susceptibility locus. Leptin and its receptor are known to be important factors in the control and regulation of body weight. Single nucleotide polymorphisms (SNPs) in the leptin receptor are associated with measures of body weight. In the present study, SNPs in the coding region of the leptin receptor were analysed and their possible association with anorexia nervosa was investigated. Two cohorts of young women, 176 Caucasian anorexia nervosa patients and 152 normal Caucasian females, were genotyped for three SNPs in the leptin receptor. There was no significant difference in allele or genotype frequency, for any SNP, between the normal controls and the cohort of anorexia subjects. There were no significant associations with any genotype and body mass index in either the control or anorexic cohorts. When the anorexic cohort was subdivided into restricting and bingeing/purging behaviours, we found no significant association with any genotype. Analysis of haplotypes showed no significant evidence of association with anorexia. In summary, leptin receptor SNPs do not appear to be important factors in the regulation of body weight in young, pre-menopausal women or have any significant association with anorexia nervosa.
Meechan DW, Quinton ND, Eastell R, et al., 2003, Complementary genetic and functional analyses of SNPs in the extracellular domain of the human leptin receptor gene (LEPR)., Annual Meeting of the American-Society-of-Human-Genetics, Publisher: UNIV CHICAGO PRESS, Pages: 347-347, ISSN: 0002-9297
Meechan DW, Quinton ND, Eastell R, et al., 2003, Molecular and functional studies of SNPs in the human receptor gene, British Human Genetics Conference, Publisher: B M J PUBLISHING GROUP, Pages: S87-S87, ISSN: 1468-6244
Quinton ND, Laird SM, Tuckerman EM, et al., 2003, Expression of leptin receptor isoforms in vitro: lack of effects of leptin on endometrial cytokine and MMP production, Am J Reprod Immunol, Vol: 50, Pages: 224-231, ISSN: 1046-7408
PROBLEM: Leptin has a key role to play in human female reproduction. Its receptor is expressed highly throughout the reproductive tract. Cytokines have an important role in preparing the endometrium for implantation and leptin is known to modulate cytokine production in other tissues. We, therefore, investigated the possible role of leptin in endometrial growth and function. METHOD OF STUDY: Reverse transcriptase polymerase chain reaction and immunocytochemistry were used to determine the pattern of expression of leptin receptor isoforms in primary human endometrial epithelial and stromal cells in culture. The effect of leptin on cell growth and on the production of cytokines [Leukaemia Inhibitory Factor (LIF), interleukin 6 and tumour necrosis factor-alpha] and matrix metalloproteinases (MMP) (MMP2 and MMP-9) was also investigated. RESULTS: Expression of the long form of the leptin was restricted to the cultured endometrial, epithelial cells. Both cultured endometrial stromal and epithelial cells expressed the short and variant isoforms of the receptor. Incubation of epithelial and stromal cell cultures with varying concentrations of leptin (0-1000 ng/mL) had no significant effect on cell growth or levels of MMP-2 or MMP-9 production. Leptin also had no significant effect on cytokine production by epithelial cells. CONCLUSIONS: This study shows for the first time, the presence of leptin receptor isoforms on endometrial, epithelial and stromal cells in culture. Leptin had no effect on cytokine and MMP production by these cells. However, it is possible that leptin affects other factors within the endometrium not investigated here.
Laird SM, Tuckerman EM, Cork BA, et al., 2003, A review of immune cells and molecules in women with recurrent miscarriage, Hum Reprod Update, Vol: 9, Pages: 163-174, ISSN: 1355-4786
Immunological rejection of the fetus due to recognition of paternal antigens by the maternal immune system, resulting in abnormal immune cells and cytokine production, is postulated to be one cause of unexplained pregnancy loss. Although there is evidence for this in rodents, there is less evidence in humans. This article focuses on studies in humans, and reviews the recent literature on the differences in immune cells and molecules in normal fertile women and women with recurrent miscarriage (RM). Although much of the evidence is contradictory, these studies do suggest differences in the expression of some immune cells and molecules in women with RM. Differences in the CD56+ population of cells are seen, and there is some evidence for an alteration in the ratio of Th1 and Th2 cytokines produced by peripheral blood monocytes (PBMCs) and clones of decidual CD4+ cells. There is also some evidence for differences in endometrial cytokine production, and in particular decreased production of pro-inflammatory cytokines such as interleukin-6. Possible reasons for the variations in data are discussed, and the importance of compartment (peripheral blood, endometrium or decidua) in which the cells and molecules are measured and the timing of the sampling, both with respect to the menstrual cycle and pregnancy (at the time or just after miscarriage) is emphasized.
Meechan DW, Quinton ND, Pieri LF, et al., 2001, Analysis of the Leptin receptor SNP, GLN223ARG, in anorexia nervosa., AMERICAN JOURNAL OF HUMAN GENETICS, Vol: 69, Pages: 583-583, ISSN: 0002-9297
Salah M, El Nahas AM, Blakemore AIF, 2001, Transforming growth factor beta-1 (TGF-β1) SNPs are associated with progressive renal insufficiency., AMERICAN JOURNAL OF HUMAN GENETICS, Vol: 69, Pages: 564-564, ISSN: 0002-9297
Laird SM, Quinton ND, Anstie B, et al., 2001, Leptin and leptin-binding activity in women with recurrent miscarriage: correlation with pregnancy outcome, Hum Reprod, Vol: 16, Pages: 2008-2013, ISSN: 0268-1161
BACKGROUND: Previous studies in humans and mice have suggested the importance of leptin in fetal growth. Recurrent miscarriage may be a result of abnormal placental and/or fetal development and therefore abnormal leptin levels may be associated with this form of pregnancy loss. METHODS: Leptin and leptin-binding activity (LBA) were measured in blood obtained from women who had a history of recurrent miscarriage (n = 53) during weeks 5-6 and 7-8 of pregnancy, and the concentrations were correlated with subsequent pregnancy outcome. RESULTS: Concentrations of leptin ranged from 1.4-62.8 ng/ml, but there was a strong correlation (r = 0.825, P < 0.001) between leptin values at weeks 5-6 and 7-8 in the same woman. Women who subsequently miscarried had significantly lower plasma leptin concentrations on both weeks 5-6 (13.34 +/- 2.1 ng/ml) (P < 0.05) and 7-8 (13.71 +/- 2.4 ng/ml) (P < 0.01) of pregnancy, than women who subsequently had a term birth (22.04 +/- 2.43 ng/ml week 5-6, 24.76 +/- 3.66 ng/ml week 7-8). LBA values ranged from 1-8.5% but there was no significant difference in LBA in blood obtained from women who subsequently miscarried or had a live birth. CONCLUSIONS: The significantly lower concentrations of leptin in women who subsequently miscarried suggest that leptin may play a role in preventing miscarriage. However, as there was a considerable overlap between the values of leptin in women who subsequently miscarried, and those that had a live birth, these measurements are of limited use in the prediction of pregnancy outcome in these women.
Quinton ND, Lee AJ, Ross RJ, et al., 2001, A single nucleotide polymorphism (SNP) in the leptin receptor is associated with BMI, fat mass and leptin levels in postmenopausal Caucasian women, Hum Genet, Vol: 108, Pages: 233-236, ISSN: 0340-6717
The human leptin (obese) receptor gene contains a number of single nucleotide polymorphisms, including GLN223ARG, which changes an amino acid on the extracellular region common to all isoforms of the receptor. Here, we demonstrate that, in postmenopausal Caucasian women, genotypes at that locus are associated with differences in body mass index (BMI), fat mass and serum leptin levels. Measurement of serum leptin-binding activity indicates that this may reflect changed receptor function associated with genotype. These observations indicate that functional variations in the leptin receptor gene are important factors in the regulation of adiposity and BMI.
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.