Association of decreased serum brain-derived neurotrophic factor (BDNF) concentrations in early pregnancy with antepartum depression.

BACKGROUND: Antepartum depression is one of the leading causes of maternal morbidity and mortality in the prenatal period. There is accumulating evidence for the role of brain-derived neurotrophic factor (BDNF) in the pathophysiology of depression. The present study examines the extent to which maternal early pregnancy serum BDNF levels are associated with antepartum depression. METHOD: A total of 968 women were recruited and interviewed in early pregnancy. Antepartum depression prevalence and symptom severity were assessed using the Patient Health Questionnaire-9 (PHQ-9) scale. Maternal serum BDNF levels were measured using a competitive enzyme-linked immunosorbent assay (ELISA). Logistic regression procedures were performed to estimate odds ratios (OR) and 95% confidence intervals (95% CI) adjusted for confounders. RESULTS: Maternal early pregnancy serum BDNF levels were significantly lower in women with antepartum depression compared to women without depression (mean ± standard deviation [SD]: 20.78 ± 5.97 vs. 21.85 ± 6.42 ng/ml, p = 0.024). Lower BDNF levels were associated with increased odds of maternal antepartum depression. After adjusting for confounding, women whose serum BDNF levels were in the lowest three quartiles (<17.32 ng/ml) had 1.61-fold increased odds (OR = 1.61, 95% CI: 1.13, 2.30) of antepartum depression as compared with women whose BDNF levels were in the highest quartile (>25.31 ng/ml). There was no evidence of an association of BDNF levels with depression symptom severity. CONCLUSIONS: Lower maternal serum BDNF levels in early pregnancy are associated with antepartum depression. These findings may point toward new therapeutic opportunities and BDNF should be assessed as a potential biomarker for risk prediction and monitoring response to treatment for antepartum depression.

The association between leukocyte telomere length and mitochondrial DNA copy number in pregnant women: a pilot study.

BACKGROUND: Both short telomere length and mitochondrial dysfunction have been associated with pregnancy complications, such as preeclampsia and intrauterine growth restriction. However, the relationship between these two biomarkers of oxidative stress, during pregnancy, is unknown. This study investigated the association of leukocyte telomere length with mitochondrial DNA (mtDNA) copy number, an indicator of mitochondrial density and possible mitochondrial dysfunction, using maternal blood samples collected from women with pregnancies uncomplicated by gestational diabetes or hypertensive disorders. METHODS: Leukocyte telomere length and mtDNA copy number were determined in 75 pregnant women using quantitative real-time quantitative PCR. Bivariate and multivariable linear regression procedures were used to evaluate associations of these two biomarkers. RESULTS: Leukocyte mtDNA copy number (natural-logarithm) was positively associated with telomere length (Pearson correlation coefficient = 0.30, p-value = 0.009). After adjusting for maternal age and plasma vitamin B12, natural-log mtDNA copy number increased by 0.80 (f = 0.80; 95% CI 0.25 - 1.34, p-value = 0.005) for every 1 unit increase of telomere length. Approximately 11% of the variation in natural-long mtDNA copy number was explained by the model (adjusted R2 = 0.11). CONCLUSIONS: This cross sectional data suggests an association of mtDNA copy number with telomere length, two emergent biological markers of potential importance in perinatal health research. The consequences of oxidative stress, cellular senescence (as reflected by relatively shorter telomere length) and mitochondrial dysfunction, on the course and outcomes of pregnancy remain to be elucidated in larger prospective studies that include these biological markers.

Mitochondrial DNA copy number and oxidative DNA damage in placental tissues from gestational diabetes and control pregnancies: a pilot study.

BACKGROUND: Available evidence supports the role of reactive oxygen species in the pathogenesis of placental insufficiency, gestational diabetes mellitus (GDM), and other pregnancy complications. Abnormal placental mitochondrial function resulting from reactive oxygen species may also be an important precedent of adverse perinatal outcomes. METHODS: We investigated the association of placental oxidative stress with placental mitochondrial DNA (mtDNA) copy number, an indicator of placental mitochondrial density and possible mitochondrial dysfunction, using samples collected from GDM cases and controls. 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative DNA damage, was measured in placentas of 19 GDM cases and 21 controls using a competitive immunoassay. Placental mtDNA copy number was determined using real-time quantitative PCR. Bivariate and multivariable linear regression procedures were used to evaluate associations of these two biomarkers. RESULTS: Placental DNA oxidation was positively associated with mtDNA copy number in both GDM and control placentas. After adjusting for maternal age, pre-pregnancy body mass index and gestational age at delivery, mtDNA copy number increased (beta = 67.0; 95% CI 27.8 - 106.2, p = 0.001) for every 0.1 ng/microg increase of placental 8-OHdG among GDM cases and controls. CONCLUSIONS: These cross sectional data suggest an association of placental mtDNA copy number with oxidative stress. The consequences of placental oxidative stress and mitochondrial dysfunction on the course and outcomes of pregnancy remain to be elucidated in larger prospective studies.

Maternal plasma advanced glycation end products concentrations in response to oral 50-gram glucose load in mid-pregnancy: a pilot study.

BACKGROUND: Accumulating evidence documents the initiation of diverse physiologic and biochemical responses subsequent to an oral glucose load. OBJECTIVES: We sought to evaluate the extent to which acute hyperglycemia, resulting from a 50-gram glucose load, contributes to changes in maternal plasma concentrations of advanced glycation end products (AGEs), a heterogeneous group of molecules formed from the non-enzymatic reaction of reducing sugars with free amino groups of proteins, lipids, and nucleic acids. METHODS: Blood specimens were collected from each participant in mid-pregnancy using standard procedures before and after a 50-gram oral glucose load. Maternal plasma methylglyoxal (MG), pentosidine and N(epsilon)-(carboxymethyl)lysine (CML) (free and bound) were measured by HPLC-MS/MS method. Non-parametric methods were employed for statistical analysis. RESULTS AND CONCLUSIONS: Median plasma MG increased 1.27 fold as a result of acute hyperglycemia. Median bound CML concentrations were elevated 21% in post-load plasma samples as compared with pre-load samples, while median free pentosidine concentrations were 51% lower (both p-values < 0.05). Future studies of larger populations and longer periods of follow-up are warranted to investigate the consequences of acute and chronic hyperglycemia on placental function and fetal development.

Genetic variations related to maternal whole blood mitochondrial DNA copy number: a genome-wide and candidate gene study.

We conducted genome-wide (GWAS) and candidate gene association studies of maternal mitochondrial DNA copy number. Maternal peripheral blood was collected during labor and delivery admission from 471 participants of a placental abruption case-control study conducted in Lima, Peru. Single nucleotide polymorphism (SNP) genotyping was performed using the Illumina Cardio-Metabo Chip. Whole blood mitochondrial DNA (mtDNA) copy number was measured using qRT-PCR techniques. We evaluated 119,629 SNPs in the GWAS and 161 SNPs (in 29 mitochondrial biogenesis and oxidative phosphorylation genes) in the candidate association study. Top hits from GWAS and the candidate gene study were selected to compute weighted genetic risk scores (wGRS). Linear regression models were used to calculate effect size estimates and related nominal p values. The top hit in our GWAS was chr19:51063065 in FOXA3 (empirical p values = 2.20e - 6). A total of 134 SNPs had p values < 0.001 including rs17111633 in CNNM1 (p values = 6.32e - 6) and chr19:51083059 in MYPOP (p values = 3.23e - 5). In the candidate association study, several SNPs in PPARG, PRKCA, SP1 and THRB were associated with mtDNA copy number (p values < 0.05). mtDNA copy number was significantly associated with wGRS based on top GWAS hits (ß = 0.49, 95% CI:0.38-0.60, p < 0.001). Variations in nuclear DNA are potentially associated with maternal mtDNA copy number.

Circulating early- and mid-pregnancy microRNAs and risk of gestational diabetes.

AIMS: Epigenetic regulators, including microRNAs (miRNAs), are implicated in type 2 diabetes, but evidence linking circulating miRNAs in pregnancy and risk of gestational diabetes (GDM) is sparse. Potential modifiers, including pre-pregnancy overweight/obesity and offspring sex, are unexamined. We hypothesized that circulating levels of early-mid-pregnancy (range 7-23weeks of gestation) candidate miRNAs are related to subsequent development of GDM. We also hypothesized that miRNA-GDM associations might vary by pre-pregnancy body-mass index (ppBMI) or offspring sex. METHODS: In a case-control analysis (36GDM cases/80 controls) from the Omega study, a prospective cohort study of pregnancy complications, we measured early-mid-pregnancy plasma levels of 10miRNAs chosen for potential roles in pregnancy course and complications (miR-126-3p, -155-5p, -21-3p, -146b-5p, -210-3p, -222-3p, -223-3p, -517-5p, -518a-3p, and 29a-3p) using qRT-PCR. Logistic regression models adjusted for gestational age at blood draw (GA) were fit to compare circulating miRNAs between cases and controls. We repeated analyses among overweight/obese (ppBMI≥25kg/m2) or lean (ppBMI<25kg/m2) women, and women with male or female offspring separately. RESULTS: Mean age was 34.3years (cases) and 32.9years (controls). GA-adjusted miR-155-5p (ß=0.260/p=0.028) and -21-3p (ß=0.316/p=0.005) levels were positively associated with GDM. MiR-146b-5p (ß=0.266/p=0.068) and miR-517-5p (ß=0.196/p=0.074) were borderline. Associations of miR-21-3p and miR-210-3p with GDM were observed among overweight/obese but not lean women. Associations of six miRNAs (miR-155-5p, -21-3p, -146b-5p, -223-3p, -517-5p, and -29a-3p) with GDM were present only among women carrying male fetuses (all p<0.05). CONCLUSIONS: Circulating early-mid-pregnancy miRNAs are associated with GDM, particularly among women who are overweight/obese pre-pregnancy or pregnant with male offspring. This area has potential to clarify mechanisms underlying GDM pathogenesis and identify at-risk mothers earlier in pregnancy.

Candidate Gene and MicroRNA Expression in Fetal Membranes and Preterm Delivery Risk.

We investigated candidate gene and microRNA (miRNA) expression in amnion and chorion in relation to risk of preterm delivery (PTD). Amnion and chorion were separated from placenta and collected at delivery from participants who delivered at term (N = 10) and from participants who delivered preterm following spontaneous labor (sPTL-PTD; N = 10), premature rupture of membranes (PPROM-PTD; N = 10), and preeclampsia (PE-PTD; N = 10). Expression of genes (metalloproteinase [MMP] 2, MMP-9, and tissue inhibitors of MMP-1) and miRNAs (miR-199a*, -202*, -210, -214, -223, and -338) was profiled using quantitative real-time polymerase chain reaction approaches. Adjusted multinomial logistic regression models were used to calculate relative risk ratios (RRR), 95% confidence intervals, and P values. Among controls, the expression of miR-199a*, -202*, and -214 was lower in the amnion compared with their expression in the chorion, whereas the expression of miR-210 was higher in the amnion compared with its expression in the chorion (all P values < .05). In the amnion, MMP-9 expression was associated with PTD risk (overall P value = .0092), and MMP-9 expression was positively associated with the risk of PPROM-PTD (RRR: 31.10) and inversely associated with the risk of PE-PTD (RRR:6.55e-6), although individual associations were not statistically significant. In addition, in the amnion, the expression of miR-210 (RRR: 0.45; overall P value = .0039) was inversely associated with the risk of PE-PTD, and miR-223 was inversely associated with all subtypes of PTD (overall P value = .0400). The amnion and chorion differ in their miRNA expression. The expression of MMP-9, miR-210, and -223 in the amnion is associated with PTD risk.

Placental mitochondrial DNA content and placental abruption: a pilot study.

BACKGROUND: Mitochondrial biogenesis and adequate energy production are important for embryogenesis and placentation. Previous studies documented alterations in maternal blood mitochondrial DNA (mtDNA) copy number-a marker of mitochondrial dysfunction-in pregnancies complicated by placental abruption. To further understand the role of mitochondrial dysfunction in the pathogenesis of placental abruption, we conducted a pilot study using placental specimen collected from 103 placental abruption cases and 102 non-abruption controls. Real-time quantitative polymerase chain reaction (PCR) was used to assess the relative copy number of mtDNA in DNA extracted from placental samples collected immediately after delivery. Logistic regression procedures were used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI). RESULTS: Higher odds of placental abruption was observed with increasing mtDNA copy number (p value for trend = 0.05). The odds of placental abruption was elevated among women who delivered placentas with higher mtDNA copy number (≥120.5, the median) as compared with those with lower values (<120.5) (adjusted OR = 2.38; 95% CI 1.11-5.08). CONCLUSION: We found preliminary evidence for associations of target tissue-specific mitochondrial dysfunction with an adverse perinatal outcome, placental abruption. Larger studies and replication of findings in other populations will further our understanding of relationships between cellular and genomic biomarkers of normal and abnormal placental function and vascular placental disorders.

Early Pregnancy Maternal Hepatocyte Growth Factor and Risk of Gestational Diabetes.

AIMS: We investigated associations of serum hepatocyte growth factor (HGF) with risk of gestational diabetes mellitus (GDM). We also examined whether pre-pregnancy overweight/obesity status or leisure-time physical activity (LTPA) modify these associations. METHODS: In a nested case-control study (173 GDM cases and 187 controls) among participants of a pregnancy cohort, early pregnancy (16 weeks of gestation, on average) serum HGF was measured using enzyme-linked immunoassay. GDM was diagnosed using American Diabetes Association guidelines. Logistic regression was used to calculate odd ratios (ORs) and 95% confidence intervals (CI). Effect modifications by pre-pregnancy overweight/obesity status or LTPA during pregnancy were examined using stratified analyses and interaction terms. RESULTS: Overall, we did not find significant associations of serum HGF with GDM risk (p-value> 0.05). However, compared with women who had low serum HGF concentrations (<2.29 ng/ml), women with high serum HGF concentrations (≥ 2.29 ng/ml) had 3.8-fold (95%CI: 1.30-10.98) and 4.5-fold (95%CI: 1.28-15.80) higher GDM risk among women who were overweight/obese, pre-pregnancy (body mass index≥25 kg/m2), or did not report LTPA, respectively. These associations were not present among women who were not overweight/obese (interaction p=0.05) or reported LTPA (interaction p=0.05). CONCLUSION: Overweight/obesity status and LTPA may modify associations of early pregnancy serum HGF with subsequent GDM risk.

Association of retinol binding protein 4 with risk of gestational diabetes.

AIM: We investigated association of maternal retinol binding protein 4 (RBP4) with risk of gestational diabetes (GDM). METHODS: GDM cases (N=173) and controls (N=187) were selected from among participants of a cohort study of risk factors of pregnancy complications. Early pregnancy (16 weeks on average) serum RBP4 concentration was measured using an ELISA-based immunoassay. Logistic regression was used to estimate unadjusted and adjusted odds ratios (ORs/aORs) and 95% confidence intervals (95%CI). RESULTS: Mean serum RBP4 was significantly higher among GDM cases compared with controls (47.1 vs. 41.1 µg/ml, respectively; p-value <0.05). Participants in the highest quartile for serum RBP4 had a 1.89-fold higher risk of GDM compared with participants in the lowest quartile (95%CI: 1.05-3.43). However, this relationship did not reach statistical significance after adjustment for confounders (aOR: 1.54; 95%CI: 0.82-2.90). Women who were ≥35 years old and who had high RBP4 (≥38.3 µg/ml, the median) had a 2.31-fold higher risk of GDM compared with women who were <35 years old and had low RBP4 (<38.3 µg/ml) (aOR: 2.31; 95%CI: 1.26-4.23; p-value for interaction=0.021). CONCLUSION: Overall, there is modest evidence of a positive association of early pregnancy elevated RBP4 concentration with increased GDM risk, particularly among women with advanced age.

Maternal blood mitochondrial DNA copy number and placental abruption risk: results from a preliminary study.

Oxidative stress and impaired placental function - pathways implicated in the pathogenesis of placental abruption - have their origins extending to mitochondrial dysfunction. To the best of our knowledge, there are no published reports of associations of placental abruption with circulating mitochondrial DNA (mtDNA) copy number - a novel biomarker of systemic mitochondrial dysfunction. This pilot case-control study was comprised of 233 placental abruption cases and 238 non-abruption controls. Real-time quantitative polymerase chain reaction (PCR) was used to assess the relative copy number of mtDNA in maternal whole blood samples collected at delivery. Logistic regression procedures were used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI). There was some evidence of an increased odds of placental abruption with the highest quartile of mtDNA copy number (P for trend = 0.09) after controlling for confounders. The odds of placental abruption was elevated among women with higher mtDNA copy number (≥336.9) as compared with those with lower values (<336.9) (adjusted OR = 1.60; 95% CI 1.04-2.46). Women diagnosed with preeclampsia and with elevated mtDNA copy number had a dramatically increased odds of placental abruption as compared with normotensive women without elevated mtDNA copy number (adjusted OR = 6.66; 95% CI 2.58-17.16). Maternal mitochondrial dysfunction appears to be associated with placental abruption in the presence of preeclampsia. Replication in other studies, particularly prospective cohort studies and those that allow for tissue specific assessment of mitochondrial dysfunction (e.g., the placenta) are needed to further understand cellular and genomic biomarkers of normal and abnormal placental function.

Maternal serum heme-oxygenase-1 (HO-1) concentrations in early pregnancy and subsequent risk of gestational diabetes mellitus.

BACKGROUND: Heme oxygenase-1 (HO-1) concentrations have been recently reported to be elevated in impaired glucose tolerance and type 2 diabetes mellitus (T2DM). However, no study has examined the association between HO-1 concentrations and gestational diabetes mellitus (GDM). METHODS: In a case-control study, nested within a prospective cohort of pregnant women (186 GDM cases and 191 women who remained eu-glycemic through pregnancy), we assessed the association of maternal serum HO-1 concentrations, measured in samples collected at 16 weeks gestation, on average, with subsequent risk of GDM. Maternal serum HO-1 concentrations were determined using ELISA. We fitted multivariate logistic regression models to derive estimates of odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Median serum HO-1 concentrations in early pregnancy were lower in women who subsequently developed GDM compared with those who did not (1.60 vs. 1.80 ng/mL, p-value=0.002). After adjusting for maternal age, race, family history of T2DM and pre-pregnancy body mass index, women with HO-1 ≥ 3.05 ng/mL (highest decile) experienced a 74% reduction of GDM risk (95% CI; 0.09-0.77) compared with women whose concentrations were<1.23 ng/mL (lowest quartile). CONCLUSION: Serum HO-1 concentrations were inversely associated with subsequent GDM risk. These findings underscore the role of oxidative stress in the pathogenesis of GDM. Additional studies are warranted to confirm the clinical utility of serum HO-1 in diagnosis of GDM, particularly in the early pregnancy.

A case-control study of maternal blood mitochondrial DNA copy number and preeclampsia risk.

A growing body of evidence suggests that mitochondrial dysfunction is associated with oxidative stress and impaired differentiation and invasion of trophoblasts, both of which have been related to preeclampsia pathogenesis. However, studies that examined circulating mitochondrial DNA (mtDNA) copy number in relation to preeclampsia are limited. Therefore, we examined association of maternal whole blood mtDNA copy number (a novel biomarker of systemic mitochondrial dysfunction) with the odds of preeclampsia. This case-control study was comprised of 144 preeclampsia cases and 407 normotensive controls. Real-time quantitative polymerase chain reaction (PCR) was used to assess the relative copy number of mtDNA in maternal whole blood samples collected at delivery. Logistic regression procedures were used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI). Median mtDNA copy number was significantly higher among preeclamptic women compared with controls (271.5 vs. 239.3, Mann-Whitney U test p-value <0.001). There was evidence of a linear trend in higher odds of preeclampsia with increasing quartiles of mtDNA copy number (P for trend=0.03) after controlling for confounders. The adjusted ORs for the successive quartiles of mtDNA copy number, compared with the referent (first quartile) were 1.30 (95%CI 0.66-2.56), 1.93 (95%CI 1.02-3.67) and 1.86 (95%CI 1.00-3.48). Our findings suggest that maternal mitochondrial dysfunction may contribute to the pathogenesis of preeclampsia. However, replication in prospective studies is needed to further investigate this relationship.

Differential Expression of HrtA1 and ADAM12 in Placentas from Preeclamptic and Normotensive Pregnancies.

BACKGROUND: High temperature requirement factor A 1 (HtrA1) and a disintegrin and metalloproteinase 12 (ADAM12), which play roles in placental implantation and placental growth, have been implicated in the pathogenesis of preeclampsia. METHODS: We investigated relative mRNA expression of both genes in placental tissues from women with preeclampsia (N=18) (average gestational age 36 weeks) and an equal number of women with normotensive pregnancies (average gestational age 39 weeks). Real-time polymerase chain reaction was used to measure mRNA extracted from term placental biopsies. Differential gene expression was evaluated using Student's T-test and fold change analyses. RESULTS: Statistically significant increases in placental HtRA1 (1.69-fold, p=0.030) and ADAM12 (1.48-fold, p=0.010) mRNA expression were observed among preeclamptic cases as compared with normotensive controls. HtrA1 expression was correlated with maternal age (p-value <0.01) among preeclampsia cases. CONCLUSION: Increases in HtRA1 and ADAM12 placental gene expression in placentas from preeclamptic pregnancies are consistent with some earlier reports of altered serum protein concentrations in preeclamptic pregnancies. This adds to the literature suggesting that defects in placentation (e.g. involving trophoblast invasion) are of etiologic importance in preeclampsia.

Oxidative DNA damage in early pregnancy and risk of gestational diabetes mellitus: A pilot study.

OBJECTIVES: To examine the association of maternal early pregnancy oxidative stress with risk of gestational diabetes mellitus (GDM). DESIGN AND METHODS: A pilot prospective, nested case-control study was conducted. Study participants were recruited before 20weeks gestation. Maternal urinary 8-hydroxydeoxyguanosine (8-OHdG), a biomarker of systemic oxidative DNA damage and repair, was measured using competitive immunoassays. Logistic regression was used to calculate odds ratio (OR) and 95% confidence intervals (95%CI). RESULTS: Elevations in early pregnancy urinary 8-OHdG concentrations were associated with increased GDM risk. After adjusting for confounders, the OR for extreme quartiles (≥8.01 vs. <4.23ng/mg creatinine) of 8-OHdG was 3.79 (95%CI 1.03-14.00). The risk for GDM was highest for overweight women with urine 8-OHdG concentrations ≥8.01ng/mg creatinine (OR=5.36, 95%CI 1.33-21.55) when compared with lean women who had 8-OHdG concentrations <8.01ng/mg creatinine. CONCLUSIONS: Elevated urine 8-OHdG concentrations in early pregnancy appear to be associated with increased GDM risk.

Maternal plasma protein profiles in response to oral 50-gram glucose load in mid-pregnancy: a pilot study.

Accumulating evidence documents the initiation of diverse physiologic and biochemical response subsequent to an oral glucose load. However, significant gaps in knowledge exist in the understanding of consequences of glucose load during pregnancy, a state of insulin resistance. Using high dimensional protein arrays, we conducted a pilot proof-of-concept and feasibility study to investigate profiles of 120 plasma proteins in pre- and post- 50-gram oral glucose challenge samples. Participants (N = 10) were selected from among women enrolled in a pregnancy cohort. Differences in plasma protein concentrations between pre- and post-glucose load challenge samples were evaluated using Student's T-test (paired) and mean fold change comparisons. Multiple testing adjusted p-values (i.e., false discovery rate q values) were computed using Benjamini-Hochberg (BH) corrections. Plasma haptoglobulin, epidermal growth factor, hemoglobin, thrombospondin-1, and S100 protein concentrations were two to five fold higher in post-glucose load compared with pre-glucose load samples (all q-values <0.05). Among women aged >31 years (above median), post-load S100 protein was elevated 9.92-fold above pre-load concentrations, while it was elevated 4.10-fold among women aged <31 years (below median). Similarly, among women with post-load glucose concentrations <101mg/dl (below median), S100 was elevated 8.26-fold while it was elevated 3.28 fold among women with post-load glucose concentrations >101mg/dl (above median). Our study findings suggest that post-glucose load changes in plasma biomarkers represent a diverse set of cellular responses including receptor for advanced glycation end products (RAGE), inflammation, oxidative stress and adipogenesis, during mid-pregnancy. Future studies of larger populations and longer periods of follow-up are warranted.

Association between insulin resistance and c-reactive protein among Peruvian adults.

OBJECTIVE: Insulin resistance (IR), a reduced physiological response of peripheral tissues to the action of insulin, is one of the major causes of type 2 diabetes. We sought to evaluate the relationship between serum C-reactive protein (CRP), a marker of systemic inflammation, and prevalence of IR among Peruvian adults. METHODS: This population based study of 1,525 individuals (569 men and 956 women; mean age 39 years old) was conducted among residents in Lima and Callao, Peru. Fasting plasma glucose, insulin, and CRP concentrations were measured using standard approaches. Insulin resistance was assessed using the homeostasis model (HOMA-IR). Categories of CRP were defined by the following tertiles: <0.81 mg/l, 0.81-2.53 mg/l, and >2.53 mg/l. Logistic regression procedures were employed to estimate odds ratios (OR) and 95% confidence intervals (CI). RESULTS: Elevated CRP were significantly associated with increased mean fasting insulin and mean HOMA-IR concentrations (p < 0.001). Women with CRP concentration >2.53 mg/l (upper tertile) had a 2.18-fold increased risk of IR (OR = 2.18 95% CI 1.51-3.16) as compared with those in the lowest tertile (<0.81 mg/l). Among men, those in the upper tertile had a 2.54-fold increased risk of IR (OR = 2.54 95% CI 1.54-4.20) as compared with those in the lowest tertile. CONCLUSION: Our observations among Peruvians suggest that chronic systemic inflammation, as evidenced by elevated CRP, may be of etiologic importance in insulin resistance and diabetes.

Molecular differentiation of Treponema pallidum subspecies.

Treponema pallidum includes three subspecies of antigenically highly related treponemes. These organisms cause clinically distinct diseases and cannot be distinguished by any existing test. In this report, genetic signatures are identified in two tpr genes which, in combination with the previously published signature in the 5' flanking region of the tpp15 gene, can differentiate the T. pallidum subspecies, as well as a simian treponeme.

Gene organization and transcriptional analysis of the tprJ, tprI, tprG, and tprF loci in Treponema pallidum strains Nichols and Sea 81-4.

The tpr gene family of Treponema pallidum subsp. pallidum, the causative agent of syphilis, has recently become the focus of intensive investigation. TprF and TprI sequences are highly conserved among different isolates and are the targets of strong humoral and cellular immune responses of the host, and immunization with a recombinant peptide from the amino terminus of these antigens has been shown to alter significantly lesion development following homologous challenge. This indicates that these antigens are expressed during infection and strongly suggests a key functionality. tprF and tprI are located immediately downstream of the tprG and tprJ genes, respectively, separated by very short intergenic spacers (55 nucleotides for G-F and 56 nucleotides for J-I). Preliminary analysis using gene-specific primers failed to amplify tprJ in the Sea 81-4 isolate. In this study, sequence and transcriptional analysis of these loci showed a similar gene organization in the Nichols and Sea 81-4 strains, a complex pattern of transcription, and the presence of G homopolymeric repeats of variable lengths upstream of the tprF, tprI, tprG, and tprJ transcriptional start sites. However, distinctive features were also identified in the Sea 81-4 isolate, including a tprG-like open reading frame in the tprJ locus, a frameshift and a premature termination in the tprG coding sequence, a longer tprG-tprF intergenic spacer, and absence of cotranscription of the tprG-tprF genes.

Antibody responses elicited against the Treponema pallidum repeat proteins differ during infection with different isolates of Treponema pallidum subsp. pallidum.

Variation in the expression of the different Tpr proteins in the syphilis spirochete, Treponema pallidum subsp. pallidum, may have important implications in its ability to evade host immune detection and cause persistent infection. In the present study we examined the pattern of antibody responsiveness to different Tpr members during infection with three isolates of T. pallidum. There was variability in the specificities and temporal patterns of reactivity of the antibodies elicited against the individual Tpr proteins, suggesting that isolates may express different repertoires of Tpr proteins during infection.