Lipid profile in various phases of menstrual cycle and its relationship with percentage plasma volume changes

Non-linear association of atherogenic index of plasma with bone mineral density a cross-sectional study

INTRODUCTION

Although there has been abundant evidence of the association between dyslipidemia as a single factor and osteoporosis, the non-linear relationship between osteoporosis and the Atherogenic Index of Plasma (AIP) has not yet been thoroughly investigated. This study aimed to investigate the complex relationship between AIP and bone mineral density (BMD) to elucidate their interrelationship.

METHODS

An analysis of 2007-2018 National Health and Nutrition Survey (NHANES) data was conducted for this study. The study enrolled 5,019 participants. Logarithmically multiplying triglycerides and high-density lipoprotein cholesterol yields the AIP (base 10). The measured variables consisted of BMD in the total femur (TF), femoral neck (FN), and lumbar spine (LS). The association between AIP and BMD was examined using a range of statistical models, such as weighted multivariable logistic regression, generalized additive model, etc. RESULTS: It was found that AIP was positively associated with BMD after adjusting for age, gender, race, socioeconomic status, degree of education, income, Consuming alcoholic beverages, osteoporosis status (Yes or No), ALT, AST, serum creatinine, and total calcium levels. Further studies supported the association link between elevated BMD and AIP. Furthermore, compared to men, females had a higher positive connection between AIP and BMD. In general, there was a curve in the reverse L-shape seen, with a point of change around 0.877, indicating a relationship between AIP and TF BMD. Moreover, a curve exhibiting an L-formed pattern, with a point of inflection at around 0.702, was seen between AIP and FN BMD. In addition, a J-shaped curve was seen, with a point of inflection at 0.092, which demonstrates the association between AIP and LS BMD.

CONCLUSION

The AIP and TF BMD curves resemble inverted L shapes, as do the AIP and FN BMD curves. The relationship between AIP and LS BMD was further demonstrated by a J-shaped curve. The results indicate a possible association between AIP and bone mineral density, which should be explored in more detail.

Lipid metabolism and endometrial receptivity

BACKGROUND

Obesity has now been recognized as a high-risk factor for reproductive health. Although remarkable advancements have been made in ART, a considerable number of infertile obese women still suffer from serial implantation failure, despite the high quality of embryos transferred. Although obesity has long been known to exert various deleterious effects on female fertility, the underlying mechanisms, especially the roles of lipid metabolism in endometrial receptivity, remain largely elusive.

OBJECTIVE AND RATIONALE

This review summarizes current evidence on the impacts of several major lipids and lipid-derived mediators on the embryonic implantation process. Emerging methods for evaluating endometrial receptivity, for example transcriptomic and lipidomic analysis, are also discussed.

SEARCH METHODS

The PubMed and Embase databases were searched using the following keywords: (lipid or fatty acid or prostaglandin or phospholipid or sphingolipid or endocannabinoid or lysophosphatidic acid or cholesterol or progesterone or estrogen or transcriptomic or lipidomic or obesity or dyslipidemia or polycystic ovary syndrome) AND (endometrial receptivity or uterine receptivity or embryo implantation or assisted reproductive technology or in vitro fertilization or embryo transfer). A comprehensive literature search was performed on the roles of lipid-related metabolic pathways in embryo implantation published between January 1970 and March 2022. Only studies with original data and reviews published in English were included in this review. Additional information was obtained from references cited in the articles resulting from the literature search.

OUTCOMES

Recent studies have shown that a fatty acids-related pro-inflammatory response in the embryo-endometrium boundary facilitates pregnancy via mediation of prostaglandin signaling. Phospholipid-derived mediators, for example endocannabinoids, lysophosphatidic acid and sphingosine-1-phosphate, are associated with endometrial receptivity, embryo spacing and decidualization based on evidence from both animal and human studies. Progesterone and estrogen are two cholesterol-derived steroid hormones that synergistically mediate the structural and functional alterations in the uterus ready for blastocyst implantation. Variations in serum cholesterol profiles throughout the menstrual cycle imply a demand for steroidogenesis at the time of window of implantation (WOI). Since 2002, endometrial transcriptomic analysis has been serving as a diagnostic tool for WOI dating. Numerous genes that govern lipid homeostasis have been identified and, based on specific alterations of lipidomic signatures differentially expressed in WOI, lipidomic analysis of endometrial fluid provides a possibility for non-invasive diagnosis of lipids alterations during the WOI.

WIDER IMPLICATIONS

Given that lipid metabolic dysregulation potentially plays a role in infertility, a better understanding of lipid metabolism could have significant clinical implications for the diagnosis and treatment of female reproductive disorders.

The atherogenic index of plasma is related to a degraded bone microarchitecture assessed by the trabecular bone score in postmenopausal women: The Camargo Cohort Study

OBJECTIVE

To assess the association between the atherogenic index of plasma (AIP) and the trabecular bone score (TBS) in postmenopausal women. Furthermore, to analyze its relationship with bone mineral density (BMD), and serum concentrations of 25OHD, PTH, and bone turnover markers.

STUDY DESIGN

Cross-sectional study nested in a population-based cohort of 1,367 postmenopausal women aged 44-94 years. Participants were classified according to TBS values (<1.230, between 1.230-1.310 and >1.310) and regarding a widely accepted cut-off point of ≥0.11 for AIP. We analyzed TBS, BMD, serum levels of 25OHD, PTH, P1NP, CTX, and clinical covariates. A multivariate analysis was performed to assess the adjusted association between AIP and TBS.

RESULTS

The mean age of participants was 63±10 years. Women with TBS values <1.230 were older, had greater BMI, greater prevalence of fractures after the age of 40 years, more years since menopause, higher values of AIP, and significantly lower levels of HDL-C, serum phosphate, and 25OHD. AIP values ≥0.11 were not associated with the presence of densitometric osteoporosis (OR=0.83, 95%CI 0.58-1.18; p = 0.30) but, in multivariate analysis, AIP values ≥0.11 were related to a degraded microarchitecture after controlling for age, BMI, smoking, diabetes status, ischemic heart disease, statin use, GFR, a fragility fracture at over 40 years of age and lumbar osteoporosis by DXA, with an adjusted OR=1.61 (95%CI 1.06-2.46; p = 0.009).

CONCLUSIONS

AIP is significantly and independently associated with a degraded bone microarchitecture as measured by TBS. In this sense, AIP might be a useful tool in the overall assessment of bone metabolism in postmenopausal women.

Plasma volume variation across the menstrual cycle among healthy women of reproductive age: A prospective cohort study

Increases in reproductive hormones like estrogen, play an important role in the remarkable increases in plasma volume observed in pregnancy. Accurate estimates of plasma volume expansion during pregnancy depend on correctly timing and measuring plasma volume in nonpregnant women. However, to date, there is no consensus on the pattern of plasma volume across the menstrual cycle. We prospectively measured plasma volume in 45 women across a single menstrual cycle. A urine-based fertility monitor was used to time three clinic visits to distinct points in the menstrual cycle: the early follicular phase (~day 2), periovulation (~day 12), and the mid-point of the luteal phase (~day 21)-based on a 28-day cycle length. Healthy women aged 18-41 years with regular menstrual cycles and a healthy body weight were enrolled in the study. At each visit, blood samples were collected before and after injection of 0.25 mg/kg body weight of indocyanine green dye (ICG). Pre- and post-ICG injection plasma samples were used to measure plasma volume. Preinjection samples were used to measure ovarian hormones and plasma osmolality. Mean plasma volume was highest during the early follicular phase (2,276 ± 478 ml); it declined to 2,232 ± 509 ml by the late follicular phase and to 2,228 ± 502 ml by the midluteal phase. This study found that overall variations in plasma volume are small across the menstrual cycle. Therefore, in clinical practice and research, the menstrual cycle phase may not be an important consideration when evaluating plasma volume among women of reproductive age.

The sensibility of the new blood lipid indicator--atherogenic index of plasma (AIP) in menopausal women with coronary artery disease

Background

Dyslipidemia is a key driver of coronary artery disease (CAD) development. This study aimed to determine whether the atherogenic index of plasma (AIP), a novel comprehensive lipid index, is an independent and reliable predictor of CAD risk in postmenopausal women.

Methods

A cohort of consecutive 4644 postmenopausal women (aged 50 or above) undergoing coronary angiography (CAG) in Anzhen Hospital (Beijing, China) from January–December 2014 was included in the analysis. Of them, 3039 women were CAD patients, and 1605 were non-CAD subjects.

Results

Relative to control subjects, TG levels in CAD patients were higher and HDL-C levels were lower. In CAD patients, non-traditional lipid profile values (TC/HDL-C, AI, and AIP) were significantly elevated relative to controls. AIP was positively correlated with TC (r = 0.157), TG (r = 0.835), LDL-C (r = 0.058), non-HDL-C (r = 0.337), TC/HDL-C (r = 0.683), LDL-C/HDL-C (r = 0.437), LCI (r = 0.662), and AI (r = 0.684), and negatively correlated with HDL-C (r = − 0.682) (all P < 0.001), but was independent of age (r = − 0.022; P = 0.130) and BMI (r = 0.020, P = 0.168). Aunivariate logistic regression analysis revealed AIP to be the measured lipid parameter most closely related to CAD, and its unadjusted odds ratio was 1.824 (95% CI: 1.467–2.267, P < 0.001). After adjusting for several CAD risk factors (age, BMI, smoking, drinking, EH, DM, hyperlipidemia, and family history of CVD, AIP was still found to represent a significant CAD risk factor (OR 1.553, 95% CI: 1.234–1.955, P < 0. 001).

Conclusion

AIP may be a powerful independent predictor of CAD risk in Chinese Han postmenopausal women, and may be superior to the traditional lipid indices.

Atherogenic index of plasma (AIP): a novel predictive indicator for the coronary artery disease in postmenopausal women

Background

Dyslipidemia is one of the most important factors for coronary artery disease (CAD). Atherogenic index of plasma (AIP) is a novel indicator involved in dyslipidemia. However, the relation between AIP and CAD in postmenopausal women remains unclear. We hypotheses that AIP is a strong predictive indicator of CAD in postmenopausal women.

Methods

A propensity score matching case–control study including 348 postmenopausal CAD cases and 348 controls was conducted in the present study.

Results

Compared with controls, CAD patients had higher levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B (APOB), but lower high-density lipoprotein cholesterol (HDL-C) and apolipoprotein A-1 (APOA-1). The values of nontraditional lipid profiles, including non-HDL-C, TC/HDL-C, LDL-C/HDL-C, non-HDL-C/HDL-C (atherogenic index, AI), TC∗TG∗LDL/HDL-C (lipoprotein combine index, LCI), log(TG/HDL-C) (atherogenic index of plasma, AIP) and APOB/APOA-1 were all significantly higher in the CAD patients. The results of Pearson correlation analyses showed AIP was positively and significantly correlated with TC (r = 0.092, P < 0.001), TG (r = 0.775, P = 0.015), APOB (r = 0.140, P < 0.001), non-HDL-C (r = 0.295, P < 0.001), TC/HDL-C (r = 0.626, P < 0.001), LDL-C/HDL-C (r = 0.469, P < 0.001), AI (r = 0.626, P < 0.001), LCI (r = 0.665, P < 0.001), APOB/APOA-1(r = 0.290, P < 0.001) and was negatively correlated with APOA-1 (r = − 0.278, P < 0.001) and HDL-C (r = − 0.665, P < 0.001). In the multivariate logistic regression analysis, AIP was an independent predictor of CAD. After adjusting for the traditional clinical prognostic factors including diabetes and hypertension, we found AIP could be an independent risk factor for CAD (odds ratio [OR], 3.290; 95% confidence interval [CI], 1.842–5.877, P < 0.001). After adjusting for multiple clinical factors include diabetes, hypertension, smoking, heart ratio, fasting blood glucose, we found AIP also could a powerful risk factor, OR = 3.619, 95%CI (2.003–6.538), P < 0.001.

Conclusion

The present study indicated that AIP might be a strong marker for predicting the risk of CAD in postmenopausal women.

Atherogenic index of plasma and risk of cardiovascular disease among Cameroonian postmenopausal women

Background

The paucity of data regarding the relationship between atherogenic index of plasma (AIP) and risk of cardiovascular disease (CVD) in postmenopausal women living in sub-Saharan Africa prompted us to conduct this study which aimed at assessing the interplay between AIP and risk of CVD among Cameroonian postmenopausal women.

Methods

This was a cross-sectional study conducted among 108 postmenopausal women in Yaoundé, Cameroon. Risk of CVD was calculated using the Framingham risk score, (FRS), and the AIP was derived as log (triglycerides/high-density lipoproteins cholesterol).

Results

Mean age of participants equaled 56.4 ± 6.9 years. AIP values ranged from -0.40 to 0.85 with a mean of 0.21 ± 0.27. There was a positive and significant correlation between AIP and body mass index (r = 0.234; p = 0.015), systolic blood pressure (r = 0.350; p < 0.001), diastolic blood pressure (r = 0.365; p < 0.001), fasting plasma glucose (r = 0.314; p = 0.001), uric acid (r = 0.374; p < 0.001), and total cholesterol (r = 0.374; p < 0.001), but not with age (r = -0.104; p = 0.284). The FRS varied between 1.2 % and >30 % with a mean of 13.4 ± 8.7 %. In univariable model, AIP significantly influenced the risk of CVD (β = 11.94; p < 0.001; R² = 0.136). But in the multivariable model, after adjusting for confounders, AIP did not impact the risk of CVD anymore (adjusted β = 1.98; p = 0.487; R² = 0.486).

Conclusion

AIP may not be an independent factor impacting the risk of CVD among Cameroonian postmenopausal women. More studies are needed to better elucidate the interaction between AIP and risk of CVD in our setting.

Relationship between lipid and lipoprotein metabolism in trimesters of pregnancy in Nigerian women: Is pregnancy a risk factor?

BACKGROUND

Changes in lipid metabolism have been shown to occur during pregnancy, to ensure a continuous supply of nutrients to the growing fetus, despite intermittent maternal food intake. Abnormal lipid metabolism has also been linked to atherosclerosis.

OBJECTIVE

To investigate the effect of pregnancy on the lipid profile and possible predisposition of pregnant Nigerian women to atherosclerosis.

SETTINGS AND DESIGN

Serum lipid and lipoprotein levels of 60 apparently healthy pregnant women aged between 25 and 45 years, attending the antenatal clinic of the U.N.T.H, Enugu and 60 apparently healthy non-pregnant, age-matched females (controls) were estimated. The test samples were collected from each subject at each of the trimesters.

MATERIALS AND METHODS

Total cholesterol (TC), high-density lipoprotein (HDL) and triglyceride (TG) were analyzed using enzymatic/spectrophotometric methods while low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL) were calculated using Friedewald's formula.

STATISTICAL ANALYSIS USED

The data obtained were analyzed with Students' t-test and Pearson's Product Moment Correlation, using graph pad prism software program and results expressed as mean ± SD. The level of significance was determined at 95% confidence level.

RESULTS AND CONCLUSION

The serum lipid levels were significantly higher (P<0.05) in all the trimesters of the pregnant women than in the controls. There was a steady increase in the serum lipid levels with increasing gestational age. A significant positive correlation (P<0.05) was observed between the lipid fractions and the different trimesters of pregnancy. TC/HDL was decreased significantly (P<0.05) in pregnant women, with increasing gestational age. Cardiac risk factor, however, decreased with gestational age, signifying possible protection from atherosclerosis. A comparison of two age groups of pregnant women (25-34 years and 35-45 years) showed no significant differences (P>0.05) in all the lipid fractions studied, suggesting no possible age-related effect on lipid metabolism in the women in their first trimester. Even with significant increase in plasma lipid during pregnancy, normal pregnancy in Nigerian women does not appear to increase the risk.

Variations in lipid levels according to menstrual cycle phase: clinical implications

Understanding variations in lipoprotein cholesterol levels throughout the menstrual cycle is important because there may be clinical implications regarding the appropriate timing of measurement and implications on the design and interpretation of studies in women of reproductive age. Our objective was to review the evidence comparing lipoprotein cholesterol levels throughout the menstrual cycle among premenopausal women. Overall, lipoprotein cholesterol levels were observed to vary in response to changing estrogen levels. Taken together, the evidence suggests that total cholesterol and LDL-C tend to be highest during the follicular phase and to decline during the luteal phase, with HDL C highest around ovulation. Based on these findings, the menstrual cycle phase should be taken into account when evaluating lipoprotein cholesterol levels among reproductive-aged women. Measuring cholesterol levels during menses is recommended for consistent comparisons as this phase can be more reliably identified than other phases, although women within National Cholesterol Education Program acceptable ranges, but near the boundaries when tested during menses, should undergo additional tests.

Effect of dietary fiber intake on lipoprotein cholesterol levels independent of estradiol in healthy premenopausal women

High-fiber diets are associated with improved lipid profiles. However, pre- and postmenopausal women respond differently to fiber intake, suggesting that endogenous estradiol mediates the effect. The authors' objective was to determine the direct effect of fiber intake on lipoprotein cholesterol levels independent of estradiol among premenopausal women. The BioCycle Study, a prospective cohort study conducted at the State University of New York at Buffalo from 2005 to 2007, followed 259 healthy women for up to 2 complete menstrual cycles. Serum lipoprotein and hormone levels were measured at 16 visits timed using fertility monitors. Fiber intake was assessed by 8 24-hour recalls. Marginal structural models with inverse probability weights for both lipoprotein and estradiol levels were used to estimate controlled direct effects of the highest category of fiber intake (≥22 g/day vs. <22 g/day) while accounting for age, body mass index, total energy, vitamin E intake, physical activity, luteinizing hormone, follicle-stimulating hormone, and progesterone. Reductions were observed in total and low density lipoprotein cholesterol in women with higher fiber intakes. Direct effects were greater than total effects. These analyses suggested that estradiol mediates at least part of the association between fiber and cholesterol among premenopausal women. More research is needed to elucidate the biologic mechanisms driving these associations.

Acute estrogen exposure does not affect basal very low-density lipoprotein-triglyceride production or oxidation in postmenopausal women

CONTEXT

Long-term hormone replacement therapy (HRT) with estradiol (E(2)) is associated with an altered lipid profile including unfavorable increases in triglyceride (TG) concentrations and augmented hepatic very low-density lipoprotein (VLDL)-TG production. There are indications that this effect of estrogens may be immediate.

OBJECTIVE

To study the in vivo effect of a single dose of E(2) on VLDL-TG kinetics and oxidation in humans.

METHODS

Eight healthy, postmenopausal women were given a single dose of either placebo or E(2) (4 mg) orally. VLDL-TG kinetics was assessed by a 240-min primed-continuous infusion of ex vivo labeled [1-(14)C]triolein-labeled VLDL. Fractional and absolute VLDL-TG oxidation was determined by hyamin trapping of exhaled (14)C label. Indirect calorimetry provided measurements of lipid oxidation.

RESULTS

Administration of 4 mg of E(2) orally rapidly increased plasma E(2) concentrations from below detection threshold to premenopausal levels. Free fatty acids (FFA) and TG concentrations were unaltered. No immediate effect was observed on either VLDL-TG production (placebo versus E(2)): 20.0+/-12.4 vs 24.1+/-10.7 micromol/min, P=0.33; VLDL-TG oxidation: 12.3+/-10.9 vs 12.6+/-5.6 micromol/min, P=0.93); or VLDL-TG clearance rates: 51.4+/-16.8 vs 64.9+/-28.8 ml/min, P=0.34).

CONCLUSIONS

Short-term E(2) elevation does not affect VLDL-TG production, oxidation, or clearance in humans. We therefore propose that HRT-associated dyslipidemia has a gradual rather than immediate onset.

No effect of menstrual cycle phase on basal very-low-density lipoprotein triglyceride and apolipoprotein B-100 kinetics

Dyslipidemia, manifested by increased plasma triglyceride (TG), increased total and LDL-cholesterol concentrations and decreased HDL-cholesterol concentration, is an important risk factor for cardiovascular disease. Premenopausal women have a less atherogenic plasma lipid profile and a lower risk of cardiovascular disease than men, but this female advantage disappears after menopause. This suggests that female sex steroids affect lipoprotein metabolism. The impact of variations in the availability of ovarian hormones during the menstrual cycle on lipoprotein metabolism is not known. We therefore investigated whether very-low-density lipoprotein (VLDL)-TG and VLDL-apolipoprotein B-100 (apoB-100) kinetics are different during the follicular (FP) and luteal phases (LP) of the menstrual cycle. We studied seven healthy, premenopausal women (age 27 +/- 2 yr, BMI 25 +/- 2 kg/m(2)) once during FP and once during LP. We measured VLDL-TG, VLDL-apoB-100, and plasma free fatty acid (FFA) kinetics by using stable isotope-labeled tracers, VLDL subclass profile by nuclear magnetic resonance spectroscopy, whole body fat oxidation by indirect calorimetry, and the plasma concentrations of lipoprotein lipase (LPL) and hepatic lipase (HL) by ELISA. VLDL-TG and VLDL-apoB-100 concentrations in plasma, VLDL-TG and VLDL-apoB-100 secretion rates and mean residence times, VLDL subclass distribution, FFA concentration and rate of appearance in plasma, whole body substrate oxidation, and LPL and HL concentrations in plasma were not different during the FP and the LP. We conclude that VLDL-TG and VLDL-apoB-100 metabolism is not affected by menstrual cycle phase.

Liver fat is not a marker of metabolic risk in lean premenopausal women

We examined the independent associations among abdominal adipose tissue (AT) depots, liver fat, cardiorespiratory fitness (CRF), and metabolic risk factors in 86 lean premenopausal women. We measured abdominal AT and liver fat by computed tomography (CT), and CRF by a maximal treadmill exercise test. Liver fat was not related to any abdominal AT depot, metabolic risk factor, or CRF (P > .10). Visceral AT mass (kilograms) remained a significant (P < .05) predictor of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), TC/high-density lipoprotein cholesterol (HDL-C), and LDL-C/HDL-C after statistical adjustment for CRF. Abdominal subcutaneous AT mass was also a significant (P < .05) correlate of TC/HDL-C and LDL-C/HDL-C after control for CRF. Visceral AT remained a significant predictor (P < .05) of TC and LDL-C after control for abdominal subcutaneous AT. Conversely, subcutaneous AT did not remain a significant correlate after control for visceral AT. However, the deep subcutaneous AT depot remained significantly associated with LDL-C, TC/HDL-C, and LDL-C/HDL-C after control for visceral AT. In contrast, visceral AT remained correlated with triglycerides (TG) alone, after control for the deep subcutaneous AT. These observations suggest that liver fat is not a determinant of metabolic risk in lean women. Conversely, both visceral and the deep subcutaneous depot are determinants of metabolic risk in premenopausal woman despite the absence of obesity.

Effect of menstrual cycle phase on exercise performance of high-altitude native women at 3600 m

At sea level normally menstruating women show increased ventilation (V̇e) and hemodynamic changes due to increased progesterone (P) and estrogen (E2) levels during the mid-luteal (L) compared to the mid-follicular (F) phase of the ovarian cycle. Such changes may affect maximal exercise performance. This repeated-measures, randomized study, conducted at 3600 m, tests the hypothesis that a P-mediated increase in V̇e increases maximal oxygen consumption (V̇O2max) during the L phase relative to the F phase in Bolivian women, either born and raised at high altitude (HA), or resident at HA since early childhood. Subjects (N=30) enrolled in the study were aged 27.7±0.7 years (mean ± s.e.m.) and non-pregnant, non-lactating, relatively sedentary residents of La Paz, Bolivia, who were not using hormonal contraceptives. Mean salivary P levels at the time of the exercise tests were 63.3 pg ml–1 and 22.9 pg ml–1 for the L and F phases, respectively. Subset analyses of submaximal (N=23) and maximal (N=13) exercise responses were conducted only with women showing increased P levels from F to L and, in the latter case, with those also achieving true V̇O2max. Submaximal exercise V̇e and ventilatory equivalents were higher in the L phase (P&lt;0.001). P levels were significantly correlated to the submaximal exercise V̇e (r=0.487, P=0.006). Maximal work output (W) was higher (approximately 5 %) during the L phase (P=0.044), but V̇O2max (l min–1) was unchanged (P=0.063). Post-hoc analyses revealed no significant relationship between changes in P levels and changes in V̇O2max from F to L (P=0.072). In sum, the menstrual cycle phase has relatively modest effects on ventilation, but no effect on V̇O2max of HA native women.