Correlation of estradiol, parathyroid hormone, interleukin-6, and soluble interleukin-6 receptor during the normal menstrual cycle

Sex-specific alterations in the gut and lung microbiome of allergen-induced mice

Introduction

Recent evidence has demonstrated that the microbiome is a driver of the underlying pathophysiological mechanisms of respiratory disease. Studies have indicated that bacterial metabolites produced in the gut and lung can impact lung inflammation and immune cell activity, affecting disease pathology. Despite asthma being a disease with marked sex differences, experimental work linking microbiomes and asthma has not considered the sex variable.

Methods

To test the hypothesis that the lung and gut microbial composition impacts allergic lung inflammation in a sex-specific manner, we evaluated lung and gut microbiome alterations in a mouse model of allergic inflammation and assessed their association with lung function and inflammation phenotypes. For this, we exposed male and female adult C57BL/6J mice intranasally to 25 µg of a house dust mite extract mix (HDM) daily, or phosphate-buffered saline (PBS) as control, for 5 weeks (n = 4-6/group). DNA from fecal pellets collected before and after the 5-week treatment, and from lung tissue collected at endpoint, was extracted using the ZymoBIOMICS®-96 MagBead DNA Kit and analyzed to determine the 16S microbiome via Targeted Metagenomic Sequencing.

Results

The HDM treatment induced a sex-specific allergic inflammation phenotype with significantly higher neutrophilia, lymphocytosis, inflammatory gene expression, and histopathological changes in females than males following exposure to HDM, but higher airway hyperresponsiveness (AHR) in males than females. In addition, sex-specific lung gene expression and associated pathways were identified HDM mix after challenge. These changes corresponded to sex-specific alterations in the gut microbiome, where the Firmicutes to Bacteroidetes ratio (F:B) was significantly reduced in fecal samples from only male mice after HDM challenge, and alpha diversity was increased in males, but decreased in females, after 5-weeks of HDM treatment.

Discussion

Overall, our findings indicate that intranasal allergen challenge triggers sex-specific changes in both gut and lung microbiomes, and induces sex-specific lung inflammation, AHR, and lung inflammatory gene expression pathways, suggesting a contribution of the lung-gut axis in allergic airway disease.

The effects of menstrual cycle phases on immune function and inflammation at rest and after acute exercise: A systematic review and meta-analysis

The immune system plays an important role in mediating exercise responses and adaptations. However, whether fluctuating hormone concentrations across the menstrual cycle may impact these processes remains unknown. The aim of this systematic review with meta-analysis was to compare baseline concentrations as well as exercise-induced changes in immune and inflammatory parameters between menstrual cycle phases. A systematic literature search was conducted according to the PRISMA guidelines using Pubmed/MEDLINE, ISI Web of Science, and SPORTDiscus. Of the 159 studies included in the qualitative synthesis, 110 studies were used for meta-analysis. Due to the designs of the included studies, only the follicular and luteal phase could be compared. The estimated standardized mean differences based on the random-effects model revealed higher numbers of leukocytes (-0.48 [-0.73; -0.23], p < 0.001), monocytes (-0.73 [-1.37; -0.10], p = 0.023), granulocytes (-0.85 [-0.1.48; -0.21], p = 0.009), neutrophils (-0.32 [-0.52; -0.12], p = 0.001), and leptin concentrations (-0.37 [-0.5; -0.23], p = 0.003) in the luteal compared to the follicular phase at rest. Other parameters (adaptive immune cells, cytokines, chemokines, and cell adhesion molecules) showed no systematic baseline differences. Seventeen studies investigated the exercise-induced response of these parameters, providing some indications for a higher pro-inflammatory response in the luteal phase. In conclusion, parameters of innate immunity showed cycle-dependent regulation at rest, while little is known on the exercise responses. Due to a large heterogeneity and a lack of cycle phase standardization among the included studies, future research should focus on comparing at least three distinct hormonal profiles to derive more specific recommendations for exercise prescription.

Menstrual Cycle Related Fluctuations in Circulating Markers of Bone Metabolism at Rest and in Response to Running in Eumenorrheic Females

This study examined potential fluctuations in bone metabolic markers across the menstrual cycle both at rest and after a 30-min bout of continuous running at 80% of V̇O_2max. Resting and post-exercise (0, 30, 90 min) sclerostin, parathyroid hormone (PTH), carboxy-terminal cross-linking telopeptide of type I collagen (β-CTXI), and procollagen type 1 N propeptide (PINP) were assessed in 10 eumenorrheic women (age: 21 ± 3 y, BMI: 23.2 ± 3.0 kg^.m²) during the mid- to late-follicular (FP: day 8.0 ± 1.4) and mid-luteal (LP: day 22.0 ± 2.5) phases of the menstrual cycle. Ovulation was determined using ovulation kits and daily measurement of oral body temperature upon awakening. Menstrual cycle phase was subsequently confirmed by measurement of plasma estradiol and progesterone. On average, resting estradiol concentrations increased from 46.3 ± 8.9 pg·mL^-1 in the FP to 67.3 ± 23.4 pg·mL^-1 in the LP (p = 0.015), and resting progesterone increased from 4.12 ± 2.36 ng·mL^-1 in the FP to 11.86 ± 4.49 ng·mL^-1 in the LP (p < 0.001). At rest, there were no differences between menstrual cycle phases in sclerostin (FP: 260.1 ± 135.0 pg·mL^-1; LP: 303.5 ± 99.9 pg·mL^-1; p = 0.765), PTH (FP: 0.96 ± 0.64 pmol·L^-1; LP: 0.79 ± 0.44 pmol·L^-1; p = 0.568), β-CTXI (FP: 243.1 ± 158.0 ng·L^-1; LP: 202.4 ± 92.3 ng·L^-1; p = 0.198), and PINP (FP: 53.6 ± 8.9 μg·L^-1; LP: 66.2 ± 20.2 μg·L^-1; p = 0.093). Main effects for time (p < 0.05) were shown in sclerostin, PTH, β-CTXI and PINP, without phase or interaction effects. Sclerostin increased from pre- to immediately post-exercise (45%; p = 0.007), and so did PTH (43%; p = 0.011), both returning to resting concentrations 30 min post-exercise. β-CTXI decreased from pre- to post-exercise (20%; p = 0.027) and was still below its pre-exercise concentrations at 90 min post-exercise (17%; p = 0.013). PINP increased immediately post-exercise (29%; p < 0.001), returning to resting concentrations at 30 min post-exercise. These results demonstrate no effect of menstrual cycle phase on resting bone marker concentrations or on the bone metabolic marker response to intense exercise.

Examining the influence of PTH(1-34) on tissue strength and composition

The lacunar-canaliculi system is a network of channels that is created and maintained by osteocytes as they are embedded throughout cortical bone. As osteocytes modify their lacuna space, the local tissue composition and tissue strength are subject to change. Although continual exposure to parathyroid hormone (PTH) can induce adaptation at the lacunar wall, the impact of intermittent PTH treatment on perilacunar adaptation remains unclear. Therefore, the primary objective of this study was to establish how intermittent PTH(1-34) treatment influences perilacunar adaptation with respect to changes in tissue composition. We hypothesized that local changes in tissue composition following PTH(1-34) are associated with corresponding gains in tissue strength and resistance to microdamage at the whole bone level. Adult male C57BL/6J mice were treated daily with PTH(1-34) or vehicle for 3 weeks. In response to PTH(1-34), Raman spectroscopy revealed a significant decrease in the carbonate-to-phosphate ratio and crystallinity across the entire tissue, while the mineral-to-matrix ratio demonstrated a significant decrease in just the perilacunar region. The shift in perilacunar composition largely explained the corresponding increase in tissue strength, while the degree of new tissue added at the endosteum and periosteum did not produce any significant changes in cortical area or moment of inertia that would explain the increase in tissue strength. Furthermore, fatigue testing revealed a greater resistance to crack formation within the existing tissue following PTH(1-34) treatment. As a result, the shift in perilacunar composition presents a unique mechanism by which PTH(1-34) produces localized differences in tissue quality that allow more energy to be dissipated under loading, thereby increasing tissue strength and resistance to microdamage. In addition, our findings demonstrate the potential for PTH(1-34) to amplify osteocytes' mechanotransduction by producing a more compliant tissue. Overall, the present study demonstrates that changes in tissue composition localized at the lacuna wall contribute to the strength and fatigue resistance of cortical bone gained in response to intermittent PTH(1-34) treatment.

Effects of alternate-day fasting or daily calorie restriction on body composition, fat distribution, and circulating adipokines: Secondary analysis of a randomized controlled trial

BACKGROUND & AIMS

Indirect comparisons suggest that alternate-day fasting (ADF) may produce greater improvements in body composition, fat distribution, and/or the adipokine profile compared to daily calorie restriction (CR), but this has not been tested directly. In a pre-planned secondary analysis of a randomized controlled trial, we compared changes in the VAT:SAT ratio, FFM:total mass ratio, and the adipokine profile between ADF and CR.

METHODS

Overweight and obese participants (n = 100) were randomized to 1) ADF (alternating every 24-h between consuming 25% or 125% of energy needs); 2) CR (consuming 75% of needs every day); or 3) control (consuming 100% of needs every day) for 24 wk.

RESULTS

The VAT:SAT ratio did not change in any group. The FFM:total mass ratio increased in both ADF (0.03 ± 0.00) and CR (0.03 ± 0.01) compared to the control group (P < 0.01), with no differences between the intervention groups. Circulating leptin decreased in both the ADF group (-18 ± 6%) and CR group (-31 ± 10%) relative to the control group (P < 0.05), with no differences between the intervention groups. Circulating levels of adiponectin, resistin, IL-6, and TNF-α did not change in either intervention group relative to the control group.

CONCLUSION

ADF and CR similarly improve the FFM:total mass ratio and reduce leptin after a 24-wk intervention.

TRIAL REGISTRATION

Clinicaltrials.gov, number NCT00960505.

Inflammatory and endothelial markers during the menstrual cycle

BACKGROUND

The menstrual cycle exhibits a pattern of repeated inflammatory activity. The present study aims to evaluate inflammatory and endothelial markers during the two phases of a menstrual cycle.

METHODS

The study cohort consisted of 102 women with regular menstrual cycles. Inflammatory and endothelial markers (interleukin-6 [IL-6], pentraxin-3 [PTX-3], hs-C reactive protein [hs-CRP], sE-selectin, sP-selectin, intracellular and vascular cell adhesion molecules [ICAM-1 and VCAM-1] and cathepsins L, B and S) were measured during the early follicular and the late luteal phase of a normal menstrual cycle.

RESULTS

Pentraxin-3 (PTX-3) and hs-CRP were significantly higher during the follicular phase compared to the luteal phase (p < 0.001 respectively p = 0.025). The other inflammatory and endothelial markers, with the exception of cathepsin B, were higher, albeit not significantly, during the follicular phase.

CONCLUSIONS

Inflammatory activity, expressed mainly by members of the pentraxin family, is higher during the early follicular compared to the luteal phase. This could be associated to menstruation but the exact mechanisms behind this pattern are unclear and might involve the ovarian hormones or an effect on hepatocytes.

Evaluation of menstrual cycle-related changes in 85 clinical laboratory analytes

OBJECTIVE

The menstrual cycle-related changes in clinical laboratory values were analysed by use of data obtained in the Asian multicentre study aimed at derivation of common reference intervals for 85 major clinical laboratory tests.

METHODS

Among 1876 healthy female volunteers, 893 had regular menstruation. They were classified into five groups according to dates between sample collection and the start of the last menstrual cycle: early follicular phase (1-6 days), late follicular phase (7-12 days), ovulatory phase (13-16 days), early luteal phase (17-22 days), and late luteal phase (23-31 days). Multiple linear regression analysis was performed to evaluate the menstrual cycle-related changes in test results. The magnitude was expressed as a standard deviation ratio of between-phase standard deviation to between-individual standard deviation based on nested ANOVA.

RESULTS

Aside from obvious changes for four sex hormones (oestradiol, progesterone, follicle-stimulating hormone, and luteinizing hormone), we observed statistically significant menstrual cycle-related changes in the following tests (standard deviation ratio >0.15): Na, Cl, creatine kinase, C-reactive protein, serum amyloid A, carbohydrate antigen 125, and parathyroid hormone were higher during the early follicular phase, while insulin, total cholesterol, and white blood cell were higher during the luteal phase. Significant associations of those test items with the four sex hormones were revealed.

CONCLUSIONS

The menstrual cycle-related changes in laboratory test results were revealed in some commonly tested items other than sex hormones. The findings are of interest in understanding female physiology in relation to hormonal changes, but the magnitude of changes is rather small and not very relevant in interpreting test results.

Serum tumor necrosis factor-α, interleukin-6, monocyte chemotactic protein-1 and paraoxonase-1 profiles in women with endometriosis, PCOS, or unexplained infertility

OBJECTIVE

To investigate the serum levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), monocyte chemotactic protein-1 (MCP-1), and Paraoxonase-1 (PON-1) during fertility treatment of women with endometriosis (Endo), PCOS or unexplained infertility (Unexpl).

METHODS

Thirty-six patients with Endo, PCOS or Unexpl undergoing controlled ovarian stimulation for IVF or IUI were consented and their serum, on day-3 (baseline) and at the end of FSH treatment (peak), was collected and investigated for levels of TNF-α, IL-6, MCP-1, and PON-1. Correlations, ANOVA and Student's t-test were used for statistical analysis.

RESULTS

Peak serum levels of IL-6, MCP-1 and PON-1 were positively correlated to E2 peak levels. TNF-α levels were inversely correlated to estradiol levels and they were lower in patients who ultimately became pregnant when compared to non-pregnant (P < 0.05). Mean TNF-α levels were significantly higher in Unexpl group (P < 0.05). The mean levels of IL-6, and MCP-1 were significantly (p < 0.05) higher in women with PCOS compared with Endo and Unexpl. No differences were found between the three clinical groups in patient's age, BMI, Day-3 FSH, PON-1 and pregnancy outcome.

CONCLUSION

Circulating cytokine levels were influenced by ovarian stimulation, as demonstrated by increased levels of IL-6, MCP-1 and PON-1, and decreased level of TNF-α at the end of controlled ovarian stimulation. While evidence of relationship between circulating cytokines with mild endometriosis was not found, PCOS was associated with elevated serum IL-6 and MCP-1 but lower TNF-α concentration. Unexplained infertility was associated with elevated TNF-α level. No relationship between serum PON-1 concentration and PCOS, mild endometriosis or unexplained infertility was noted.

The role of sex hormones in induced-systemic inflammation in female albino rats

Estrogen (E(2)) and progesterone (P) hormones have a pro-inflammatory and an anti-inflammatory role under different conditions. The current study explored this phenomenon in the context of septic inflammation.

MATERIALS AND METHODS

This study involved 48 female albino rats. E(2) (4 mg/100 g body weight (b.w.) and P (5 mg/kg b.w.) were administered to ovariectomized (OVX) rats after systemic inflammation (SI) induced by puncturing the caecum I cm from its end with a single hole by using a 21-gauge needle. Key indices of inflammation and apoptosis were evaluated.

RESULTS

OVX animals subjected to SI showed significantly increased levels of serum tumor necrosis factor-alpha (TNF-u), C reactive protein (CRP) and alanine aminotransferase (ALT). They also showed higher levels of expression of the enzyme inducible nitric oxide synthase (iN OS); 312 ± 43 mg/ml; in the liver, and the activity of both cyclooxygenase 2 (COX-2); 59.4 ± 3.2 U/ml; and caspase 3 enzymes; 6.3 ± 0.54 ng/ml; when compared to non-OVX animals subjected to (SI), (180 ± 3 mg/ml, 16.4 ± 1.69 U/ml, 0.98 ± 0.23 ng/ml respectively). Administration of E(2) resulted in a significant reduction of all serum and liver tissue parameters of inflammation (e.g.decreased iNOS; 193 ± 28 mg/ml and COX-2; 27.6 ± 3.91 U/ml) and decreased apoptosis (Caspase 3; 1.18 ± 0.21 ng/ml). In contrast, OVX animals injected with P before induction of SI showed a significant rise of all measured parameters.

CONCLUSIONS

E(2) and Pin physiological levels have contrasting though complementary roles in regulation of the immune system possibly allowing a limited inflammatory response while preventing excessive damage to the tissues.

Ovarian endometrioma but not deep infiltrating endometriosis is associated with increased serum levels of interleukin-8 and interleukin-6

Cytokines, and specifically interleukin 6 (IL-6) and interleukin 8 (IL-8), have been associated with the pathogenesis of endometriosis. We studied serum concentrations of IL-6 and IL-8 in patients with deep infiltrating endometriosis (DIE) or ovarian endometriomas (OE), but no other forms of associated endometriosis disease type. We carried out a case-control study including 19 patients with OE alone (OE group), 14 patients with DIE alone (DIE group) and 24 healthy patients without endometriosis (C group). Serum concentrations of IL-6 and IL-8 were measured in the three groups of patients. Serum levels of both IL-6 and IL-8 were significantly higher in the OE group. A high positive correlation was found between serum IL-6 and IL-8 levels in the OE group but not in the DIE and C groups. Serum IL-8 alone achieved the highest predictive value of the presence of OE (adjusted OR: 1.44; sensitivity: 78.2%; specificity: 76.2%). The combination of IL-6 and IL-8 levels did not significantly improve the discrimination between subjects with OE and those with DIE over that of IL-8. OE but not DIE are associated with increased serum levels of IL-6 and IL-8, and thus these may become useful tools for discriminating OE alone from DIE.

Circulating inflammation markers and risk of epithelial ovarian cancer

BACKGROUND

Factors contributing to chronic inflammation appear to be associated with increased risk of ovarian cancer. The purpose of this study was to assess the association between circulating levels of inflammation mediators and subsequent risk of ovarian cancer.

METHODS

We conducted a case-control study of 230 cases and 432 individually matched controls nested within three prospective cohorts to evaluate the association of prediagnostic circulating levels of inflammation-related biomarkers (IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p40, IL-12p70, IL-13, TNFα, IL-1Ra, sIL-1RII, sIL-2Ra, sIL-4R, sIL-6R, sTNF-R1, and sTNF-R2) measured using Luminex xMap technology with risk of ovarian cancer.

RESULTS

We observed a trend across quartiles for IL-2 (OR(Q4 vs. Q1): 1.57, 95% CI: 0.98-2.52, P = 0.07), IL-4 (OR(Q4 vs. Q1): 1.50, 95% CI: 0.95-2.38, P = 0.06), IL-6 (OR(Q4 vs. Q1): 1.63, 95% CI: 1.03-2.58, P = 0.03), IL-12p40 (OR(Q4 vs. Q1): 1.60, 95% CI: 1.02-2.51, P = 0.06), and IL-13 (OR(Q4 vs. Q1): 1.42, 95% CI: 0.90-2.26, P = 0.11). Trends were also observed when cytokines were modeled on the continuous scale for IL-4 (P trend = 0.01), IL-6 (P trend = 0.01), IL-12p40 (P trend = 0.01), and IL-13 (P trend = 0.04). ORs were not materially different after excluding cases diagnosed less than 5 years after blood donation or when limited to serous tumors.

CONCLUSIONS AND IMPACT

This study provides the first direct evidence that multiple inflammation markers, specifically IL-2, IL-4, IL-6, IL-12, and IL-13, may be associated with risk of epithelial ovarian cancer, and adds to the evidence that inflammation is involved in the development of this disease.

Altered kinetics of interleukin-6 and other inflammatory mediators during exercise in children with type 1 diabetes

BACKGROUND

Leukocyte mobilization and secretions of cytokines, chemokines, and growth factors in children during exercise are necessary biochemical signals for physiological growth and long-term cardiovascular protection. Because of glycemic instability, altered exercise responses, particularly the proinflammatory cytokine interleukin (IL)-6, may occur in type 1 diabetes mellitus (T1DM) that could influence the onset/progression of diabetic vascular complications. Relatively little is known, however, on most molecular aspects of immunomodulatory adaptation to exercise in diabetic children.

METHODS

We therefore studied 21 children (age, 13.4 +/- 0.3 years; 13 boys/8 girls) with T1DM and 21 age-matched healthy controls during 30 minutes of intense and intermittent cycling exercise. Euglycemia was maintained during and for greater than 90 minutes before exercise; blood samples for IL-6 and other cytokines/chemokines were drawn before, during (every 6 minutes), and after (every 15 minutes) exercise.

RESULTS

In T1DM, exercise-induced IL-6 peak occurred earlier and with greater magnitude than that in controls; an exploratory analysis of additional inflammatory mediators displayed a similarly accelerated/exaggerated pattern in T1DM, including the kinetic profiles of tumor necrosis factor alpha, IL-4, IL-12p70, IL-17, granulocyte-monocyte colony-stimulating factor, monocyte chemoattractant protein-1, macrophage inflammatory protein-1alpha, and eotaxin (interferon-inducible protein-10 was the only measured variable essentially indistinguishable between groups).

CONCLUSION

Therefore, during intense and intermittent exercise, significant alterations in the immunologic pattern of inflammatory regulation occurred in children with T1DM as compared with healthy controls. Our findings underscore how the understanding of all the underlying molecular mechanisms is a necessary prerequisite for achieving effective use of exercise and the full manifestation of its health benefits, particularly in understudied populations such as children with T1DM who are at increased risk for cardiovascular complications.

Serum levels of soluble vascular cell adhesion molecule-1, tumor necrosis factor-alpha, and interleukin-6 in in vitro fertilization cycles

OBJECTIVE

To assess whether gonadotropin-induced changes in E(2) alter serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1) and proinflammatory cytokines.

DESIGN

Prospective collection of serum in patients undergoing IVF.

SETTING

University hospital.

PATIENT(S)

Twenty-four infertile women.

INTERVENTION(S)

Serum collection at baseline, in the mid and late follicular phases, at oocyte retrieval, and in the mid and late luteal phases.

MAIN OUTCOME MEASURE(S)

Samples were assayed for sVCAM-1, tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and E(2).

RESULT(S)

The VCAM-1 was maximally suppressed in the luteal phase. Luteal sVCAM-1 levels correlated [1] positively with the patient's age, units of gonadotropins, day 3 FSH levels and [2] negatively with [a] the follicular, retrieval, and luteal E(2) levels and [b] the number of preovulatory follicles and oocytes retrieved. Similar correlations were noted in the late luteal phase. Serum TNF-alpha reached a peak in the mid-follicular phase and a nadir in the luteal phase. The TNF-alpha levels at retrieval correlated [1] positively with the patient's age and [2] negatively with E(2) and number of preovulatory follicles and retrieved oocytes. The IL-6 levels were suppressed in the follicular phase and correlated negatively with E(2) levels.

CONCLUSION(S)

Changes in E(2) levels seen during gonadotropin stimulation significantly alter VCAM-1 expression and induce changes in serum IL-6 and TNF-alpha levels.

Kinetic profiles of 18 systemic pro- and anti-inflammatory mediators during and following exercise in children

While acute changes in systemic pro-/antiinflammatory cytokines occur with exercise, individual kinetics during and following exercise remain unclear; particularly, information is scarce regarding children. This study investigated the exercise-induced kinetic profiles of major pro-/anti-inflammatory mediators in 21 healthy children (13.9 +/- 0.8 yr, 7 M/14 F). Exercise was 30 min of intermittent cycling at approximately 80% VO2max. Multiple blood samples were drawn at baseline, during, and following exercise for cytokines assay. IL-1alpha, IL-6, IL-17, IL-8, IP-10, MIP-1alpha, and MIP-1beta initially decreased (nadir: 14-19 min into exercise) and subsequently exceeded baseline levels (peaks: 20-24 min into exercise). TNF-alpha, IL-12p70, IL-1RA, IL-4, EGF, TGF-alpha, GM-CSF, Eotaxin, and MCP-1 were moderately and persistently decreased throughout. VEGF was unchanged; sCD40L was elevated during exercise and recovery. Our results indicate that key immunomodulators display non-linear, biphasic kinetic profiles in response to exercise, suggesting that detection of exercise-induced changes over baseline may depend on exercise duration and sampling timing.

Cyclical changes in calcium metabolism across the menstrual cycle in women with premenstrual dysphoric disorder

CONTEXT

Alterations in calcium homeostasis have long been associated with affective disorders. Recently, it has been suggested that abnormalities in calcium metabolism may be responsible for some affective and somatic symptoms in women with premenstrual syndrome.

OBJECTIVE

Our objective was to measure fluctuations and group differences in calcium-regulating hormones across the menstrual cycle in women with and without premenstrual dysphoric disorder (PMDD).

DESIGN

We conducted a cross-sectional and prospective study of women with and without PMDD. Participating women underwent 2 months of self-assessment symptom screening and 1 month of hormonal evaluation.

RESULTS

Calcium-regulating hormones varied significantly across the menstrual cycle in both groups. Total serum, ionized and urine calcium, pH, intact PTH, and 1,25-dihydroxyvitamin D [1,25(OH)(2)D] varied significantly over the menstrual cycle. The PMDD group, when compared with controls, had significantly lower ionized calcium at phase 1 (menses) (1.166 +/- 0.072 vs. 1.182 +/- 0.087 mmol/liter; P = 0.027), significantly lower urine calcium excretion at three of the five phases (late follicular phase 2, midcycle phase 3, and early luteal phase 4), and significantly lower 1,25(OH)(2)D at luteal phase 4 (45.0 +/- 27.5 vs. 50.6 +/- 33.8 pg/ml; P = 0.032).

CONCLUSIONS

Cyclical fluctuations of the calcium-regulating hormones may help us better understand some of the psychological and somatic features of PMDD. The lack of responsiveness in vitamin D metabolism resulting in a decline in 1,25(OH)(2)D during the luteal phase of the menstrual cycle may serve as the biological trigger for the classical features of PMDD.

Impact of gender and menstrual cycle phase on plasma cytokine concentrations

OBJECTIVE

The lifetime prevalence of major depression is twice as high in females as in males. Depression is known to increase at periods where there are changes in gonadal hormones. We examined pro- and anti-inflammatory cytokine levels during the normal menstrual cycle of healthy females compared to similar time points in healthy males.

METHODS

Plasma concentrations of interleukin (IL)-4, IL-6, IL-8, IL-10, tumour necrosis factor-alpha (TNF-alpha) and soluble IL-6 receptor (sIL-6R) were measured with enzyme-linked immunosorbent assays in healthy females during the normal ovulatory menstrual cycle and also in males at similar time points.

RESULTS

The luteal phase of the menstrual cycle is associated with increased production of sIL-6R, IL-4 and TNF-alpha compared to the early follicular phase. No change was observed in IL-6, IL-8 and IL-10 concentration throughout the menstrual cycle. We found IL-4 positively correlated with oestrogen while TNF-alpha positively correlated with progesterone. Females were found to have significantly higher concentrations of TNF-alpha and sIL-6R across all phases of the menstrual cycle, compared to males across similar time points.

CONCLUSION

The normal menstrual cycle is associated with increased production of sIL-6R, IL-4 and TNF-alpha in the luteal phase compared to the early follicular phase. Females have significantly higher concentrations of sIL-6R and TNF-alpha at all time points across the menstrual cycle than males.

Serum levels of soluble vascular cell adhesion molecule-1 are decreased in women receiving oral contraceptives compared with normally menstruating women: implications in atherosclerosis

OBJECTIVE

The primary objective was to assess whether short-term changes in estradiol (E2), such as those observed in the menstrual cycle, alter serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1), and whether VCAM-1 expression is suppressed in long-term users of exogenous estrogens. The secondary objective was to assess the association, if any, between inflammatory cytokines and expression of sVCAM-1.

DESIGN

Prospective collection of serum samples in healthy volunteers.

SETTING

University hospital.

PATIENTS(S)

Thirty-one normally menstruating women and 37 oral contraceptive (OC) users. Interventions included serum collection in the early follicular, late follicular, and midluteal phases of the menstrual cycle and once in oral contraceptive users.

MAIN OUTCOME MEASURE(S)

Samples were assayed for sVCAM-1, tumor necrosis factor alpha (TNF-alpha), and interleukin (IL)-6 by enzyme-linked immunoabsorbent assay (ELISA). Estradiol (E2) was measured by radioimmunoassay (RIA).

RESULT(S)

Oral contraceptive users had significantly lower serum levels of sVCAM-1 compared with normally menstruating women. No significant change was noted in the mean values of sVCAM-1 throughout the menstrual cycle, despite the significant change in 17beta-estradiol levels. Throughout the menstrual cycle, a significant correlation was noted between the serum levels of TNF-alpha and sVCAM-1. The serum levels of IL-6 correlated with those of sVCAM-1 in the late follicular and midluteal phase of the cycle. Similar correlations were observed in OC users.

CONCLUSION(S)

Long-term exposure to exogenous estrogens suppresses serum levels of sVCAM-1. Short-term changes in endogenous estrogens, as observed during the menstrual cycle, may not alter VCAM-1 expression; TNF-alpha and IL-6 may play a role in the regulation of VCAM-1 expression in vivo.

Variability of serum levels of tumor necrosis factor-alpha, interleukin 6, and soluble interleukin 6 receptor over 2 years in young women

Serum levels of tumor necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6), and soluble interleukin 6 receptor (sIL-6R) have been studied as risk factors of cardiovascular disease in longitudinal studies. However, it is unknown about their long-term intra-individual variations and whether single measurements of these cytokines and receptor are reliable biomarkers in epidemiological studies. In this study, serum levels of TNF-alpha, IL-6, and sIL-6R were assayed by ELISAs in 36 young, healthy women from whom three blood samples were collected at 12-month intervals over 2 years, and the intraclass correlation coefficients (ICC) were estimated. The ICC of 0.73 (95% CI=0.49-0.79) for TNF-alpha was comparable to those of other commonly used biomarkers, justifying its use in epidemiological studies. The ICC of 0.48 (95% CI=0.25-0.58) for IL-6 was not optimal. However, IL-6 has been demonstrated as a consistent risk factor for cardiovascular disease, suggesting it could still be a useful biomarker if its disease association is substantial. The ICC of 0.36 (95% CI=0.10-0.47) for sIL-6R was relatively low, and multiple samples would need to be collected in prospective studies for this receptor.

Influence of gender, menstrual phase, and oral contraceptive use on immunological changes in response to prolonged cycling

This study determined the influence of gender, menstrual phase (MP), and oral contraceptive (OC) use on immunological changes in response to endurance exercise. Twelve women and 11 men similar in age, aerobic power, and activity level cycled for 90 min at 65% maximal aerobic power. Women were OC users (n = 6) or nonusers (NOC) and cycled during the follicular (Fol) and the luteal (Lut) phases. Venous blood was collected before and after exercise to determine leukocyte counts, IL-6 concentrations, and cortisol. Higher resting levels of neutrophils (approximately 1.5-fold) and cortisol (approximately 2.5-fold) were found in OC vs. NOC and men. Exercise-induced immune cell count and IL-6 changes were similar between men and NOC, except for an approximately 38% greater lymphocyte response in NOC vs. men (P = 0.07). Neutrophil, monocyte, and lymphocyte responses to exercise during Lut in OC were greater than during Fol and also greater than the responses in men (P < or = 0.003). Changes in immune cell counts were consistently greater during Lut in OC vs. NOC, regardless of MP, but only neutrophil responses reached statistical significance (P = 0.01). The exercise-induced change in IL-6 was approximately 80% greater in NOC vs. OC during Fol (P = 0.06), but it was similar between these groups during Lut. Cortisol changes with exercise were not different between groups or MP. These results highlight the necessity to control for gender, and in particular OC use, when designing studies evaluating exercise and immunology.

Serum interleukin-6 levels and bone mineral density at the femoral neck in post-menopausal women with Type 1 diabetes

BACKGROUND

Although osteopenia is often reported in Type 1 diabetes mellitus, the pathogenic mechanisms are not fully understood. Oestrogen deficiency also leads to decreased bone mineral density (BMD). Enhanced interleukin-6 (IL-6) production among Type 1 diabetic patients could be involved in the pathogenesis of diabetic bone loss since it is a potent bone resorbing cytokine.

AIMS

To evaluate the relationship between serum bioactive IL-6 levels and BMD at the femoral neck of post-menopausal women with Type 1 diabetes.

METHODS

We studied BMD, urine excretion of deoxypirydynoline crosslinks, serum bioactive IL-6 and soluble IL-6 receptor (sIL-6R) levels in 20 post-menopausal women with Type 1 diabetes mellitus, and compared these results with 20 matched healthy post-menopausal controls.

RESULTS

Post-menopausal women with Type 1 diabetes had significantly lower BMD at the femoral neck and increased serum bioactive IL-6 levels compared with the control group, but no relationship was observed between these variables in a multiple regression analysis. Using BMD at the femoral neck of diabetic women as the dependent variable in the multiple step regression analysis model, we found that independent variables that were strongly associated with bone mass at the femoral neck in this group were: time since menopause and duration of diabetes.

CONCLUSIONS

Although our study had a small sample size, we found that post-menopausal women with Type 1 diabetes mellitus present lower bone mass and higher serum bioactive IL-6 levels than matched healthy controls, but we were unable to find a correlation between these two parameters.

A osteoporose e os distúrbios endócrinos da tireóide e das gônadas

Apesar da dedicação incessante dos pesquisadores no estudo da osteoporose, muito ainda necessita ser elucidado. A deficiência dos esteróides sexuais, principalmente a de estrógeno, é considerada a principal causa de osteoporose, embora existam inúmeros outros fatores envolvidos. O hipertireoidismo, por exemplo, é considerado um dos fatores de risco para indução ou agravamento da osteoporose e tem despertado o interesse para o estudo dos efeitos de T3 e T4 sobre o metabolismo ósseo. Embora o hipotireoidismo e a afuncionalidade das gônadas seja uma associação freqüente na mulher, a hipofunção da tireóide não é considerada fator de risco para a osteoporose da menopausa. Assim, o estudo da inter-relação entre os distúrbios endócrinos, tão comuns na idade avançada, e a osteoporose é fundamental, pois deste conhecimento poderão advir meios de controle e tratamento adequados, bem como a definição da real natureza do distúrbio ósseo. O objetivo desta revisão é apresentar e discutir alguns aspectos da osteoporose e sua inter-relação com os distúrbios endócrinos da tireóide e das gônadas.

The role of transsignalling via the agonistic soluble IL-6 receptor in human diseases

The activation of cells that do not express the membrane bound interleukin-6 6 receptor (IL-6R) by IL-6 and the soluble IL-6 receptor (sIL-6R) is termed transsignalling. Transsignalling may be an pathogenetic factor in human diseases as diverse as multiple myeloma (MM), Castleman's disease, prostate carcinoma, Crohn's disease, systemic sclerosis, Still's disease, osteoporosis and cardiovascular diseases. IL-6 and sIL-6R may directly or indirectly enhance their own production on endothelial or bone marrow stromal cells. Positive feedback autocrine loops thus created in affected organs may either cause or maintain disease progression. In autoimmune or vasculitic disease, the ability of the IL-6/sIL-6R complex to inhibit apoptosis of autoreactive T-cells may be central to the development of tissue specific autoimmunity. The anti-apoptotic effect of the IL-6/sIL-6R complex may be involved in tumour genesis and resistance to chemotherapy. Only in rare cases, where counterregulation has failed, there is a notable systemic effect of IL-6/sIL-6R. Appropriate animal models are necessary to establish the pathogenetic role of the IL-6/sIL-6R complex. A specific treatment option for diseases influenced by the sIL-6R could be based on gp130-Fc, a soluble gp130 (sgp130) linked to the Fc-fragment of IgG1. gp130-Fc has shown efficacy in vivo in animal models of Crohn's disease.

Changes in proinflammatory cytokine activity after menopause

There is now a large body of evidence suggesting that the decline in ovarian function with menopause is associated with spontaneous increases in proinflammatory cytokines. The cytokines that have obtained the most attention are IL-1, IL-6, and TNF-alpha. The exact mechanisms by which estrogen interferes with cytokine activity are still incompletely known but may potentially include interactions of the ER with other transcription factors, modulation of nitric oxide activity, antioxidative effects, plasma membrane actions, and changes in immune cell function. Experimental and clinical studies strongly support a link between the increased state of proinflammatory cytokine activity and postmenopausal bone loss. Preliminary evidence suggests that these changes also might be relevant to vascular homeostasis and the development of atherosclerosis. Better knowledge of the mechanisms and the time course of these interactions may open new avenues for the prevention and treatment of some of the most prevalent and important disorders in postmenopausal women.

Nitrogen Metabolism and Bone Metabolism Markers in Healthy Adults during 16 Weeks of Bed Rest

Background: The associations between nitrogen metabolism and bone turnover during bed rest are still not completely understood.

Methods: We measured nitrogen balance (nitrogen intake minus urinary nitrogen excretion) and biochemical metabolic markers of calcium and bone turnover in six males before head-down tilt bed rest (baseline), during 2, 10, and 14 weeks of immobilization, and after reambulation.

Results: The changes in nitrogen balance were highest between baseline and week 2 (net change, −5.05 ± 1.30 g/day; 3.6 ± 0.6 g/day at baseline vs −1.45 ± 1.3 g/day at week 2; P&lt;0.05). In parallel, serum intact osteocalcin (a marker of bone formation) was already reduced and renal calcium and phosphorus excretions were increased at week 2 (P &lt;0.05). Fasting serum calcium and phosphorus values and renal excretion of N-telopeptide (a bone resorption marker) were enhanced at weeks 10 and 14 (P &lt;0.05–0.001), whereas serum concentrations of parathyroid hormone, calcitriol, and type I collagen propeptide (a marker of bone collagen formation) were decreased at week 14 (P &lt;0.05–0.01). Significant associations were present between changes of serum intact osteocalcin and 24-h calcium excretion (P &lt;0.001), nitrogen balance and 24-h phosphorus excretion (P &lt;0.001), nitrogen balance and renal N-telopeptide excretion (P &lt;0.05), and between serum osteocalcin and nitrogen balance (P &lt;0.025).

Conclusions: Bone formation decreases rapidly during immobilization in parallel with a higher renal excretion of intestinally absorbed calcium. These changes appear in association with the onset of a negative nitrogen balance, but decreased bone collagen synthesis and enhanced collagen breakdown occur after a time lag of several weeks.