Leptin stimulates aromatase in the growth plate: limiting catch-up growth efficiency

Nutrition, Other Environmental Influences, and Genetics in the Determination of Human Stature

Linear growth during three distinct stages of life determines attained stature in adulthood: namely, in utero, early postnatal life, and puberty and the adolescent period. Individual host factors, genetics, and the environment, including nutrition, influence attained human stature. Each period of physical growth has its specific biological and environmental considerations. Recent epidemiologic investigations reveal a strong influence of prenatal factors on linear size at birth that in turn influence the postnatal growth trajectory. Although average population height changes have been documented in high-income regions, stature as a complex human trait is not well understood or easily modified. This review summarizes the biology of linear growth and its major drivers, including nutrition from a life-course perspective, the genetics of programmed growth patterns or height, and gene-environment interactions that determine human stature in toto over the life span. Implications for public health interventions and knowledge gaps are discussed.

Serum leptin level in Sudanese women with unexplained infertility and its relationship with some reproductive hormones

BACKGROUND

The excessive concentration of leptin has negative effects on all aspects of female reproduction. Despite this established relationship, the exact role of leptin in women’s fertility is not clear enough and needs more clarification.

AIM

To evaluate the serum leptin levels in Sudanese women and to ascertain the relationship between serum leptin levels and unexplained infertility (UI).

METHODS

A matched (age and body mass index) case-control study was conducted from March 2021 to February 2022. The study samples were 210 women with UI and 190 fertile women of reproductive age who were attending the maternity hospitals and fertility clinics in Khartoum state Sudan. The serum concentration of leptin and other serum biomarkers were determined using enzyme-linked immunosorbent assays.

RESULTS

The results showed that there was a highly statistically significant difference between the two groups (P < 0.001) for all examined eight biomarkers. Whereby, leptin, luteinizing hormone (LH)/follicular stimulating hormone (FSH) ratio, prolactin hormone (PRL) and testosterone (T) were significantly higher in the UI group compared with the control group. In contrast, FSH and estradiol (E2)/T ratio were significantly lower in the UI group than in the control group and the effect size test for the difference between the two groups was very large (effect size > 0.80), for leptin level, LH/FSH ratio, PRL level, and E2/T ratio, and large (effect size 0.50- ≤ 0.80) for FSH and T.

CONCLUSION

This study reveals that leptin could be a potential biomarker for UI in Sudanese women and it may be useful for identifying women with a high risk of infertility.

Associations of Obesity with Linear Growth and Puberty

BACKGROUND

The prevalence of obesity in childhood has increased dramatically in recent decades with increased risk of developing cardiometabolic and other comorbidities. Childhood adiposity may also influence processes of growth and puberty.

SUMMARY

Growth patterns of obesity during childhood have been shown to be associated with increased linear growth in early childhood, leading to accelerated epiphyseal growth plate (EGP) maturation. Several hormones secreted by the adipose tissue may affect linear growth in the context of obesity, both via the growth hormone IGF-1 axis and via a direct effect on the EGP. The observation that children with obesity tend to mature earlier than lean children has led to the assumption that the degree of body fatness may trigger the neuroendocrine events that lead to pubertal onset. The most probable link between obesity and puberty is leptin and its interaction with the kisspeptin system, which is an important regulator of puberty. However, peripheral action of adipose tissue could also be involved in changes in the onset of puberty. In addition, nutritional factors, epigenetics, and endocrine-disrupting chemicals are potential mediators linking pubertal onset to obesity. In this review, we focused on interactions of obesity with linear growth and pubertal processes, based on basic research and clinical data in humans.

KEY MESSAGE

Children with obesity are subject to accelerated linear growth with risk of impaired adult height and early puberty, with its psychological consequences. The data highlight another important objective in combatting childhood obesity, for the prevention of abnormal growth and pubertal patterns.

Dietary Complex and Slow Digestive Carbohydrates Promote Bone Mass and Improve Bone Microarchitecture during Catch-Up Growth in Rats

Catch-up growth is a process that promotes weight and height gains to recover normal growth patterns after a transient period of growth inhibition. Accelerated infant growth is associated with reduced bone mass and quality characterized by poor bone mineral density (BMD), content (BMC), and impaired microarchitecture. The present study evaluated the effects of a diet containing slow (SDC) or rapid (RDC) digestible carbohydrates on bone quality parameters during the catch-up growth period in a model of diet-induced stunted rats. The food restriction period negatively impacted BMD, BMC, and microarchitecture of appendicular and axial bones. The SDC diet was shown to improve BMD and BMC of appendicular and axial bones after a four-week refeeding period in comparison with the RDC diet. In the same line, the micro-CT analysis revealed that the trabecular microarchitecture of tibiae and vertebrae was positively impacted by the dietary intervention with SDC compared to RDC. Furthermore, features of the cortical microstructure of vertebra bones were also improved in the SDC group animals. Similarly, animals allocated to the SDC diet displayed modest improvements in growth plate thickness, surface, and volume compared to the RDC group. Diets containing the described SDC blend might contribute to an adequate bone formation during catch-up growth thus increasing peak bone mass, which could be linked to reduced fracture risk later in life in individuals undergoing transient undernutrition during early life.

Leptin levels in women with unexplained infertility: A systematic review and meta-analysis

BACKGROUND

Unexplained infertility (UI) is usually used for any heterosexual couple who failed to have a successful clinical pregnancy without identifying clear causes after they undergo all standard fertility tests. Evidence shows that leptin is one of the most accurate biomarkers for UI. Nevertheless, conflicting results regarding leptin levels in women with UI have been reported.

AIM

To find the serum leptin levels in women with UI.

METHODS

All studies written in English and conducted before April 30, 2021 from PubMed/MEDLINE, Embase, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, Google Scholar, OpenGrey, OATD, and the infertility conference abstract were included. Studies were found eligible if they provided the mean and standard deviation of leptin for the case group and control group. The quality assessment of individual studies was evaluated using the Joanna Briggs Institute Quality Assessment Tool. Data synthesis and statistical analysis were done using STATA software version 16.

RESULTS

A total of 378 studies were reviewed, and just six studies that fulfilled the eligibility criteria were included in this meta-analysis. The pooled result showed that leptin levels were significantly higher in women with UI compared to fertile women, with a standardized mean difference of 0.97 (95% confidence interval: -0.49-2.43). However, heterogeneity across studies was highly significant (P < 0.00001; I² = 98.8%).

CONCLUSION

The results of this study suggest that leptin levels are elevated in women with UI compared with fertile women; hence, leptin could be a potential biomarker for UI in women, and it may be useful for identifying women with a high risk of infertility.

Decrease in leptin mediates rat bone metabolism impairments during high-fat diet-induced catch-up growth by modulating the OPG/RANKL balance

Due to catch-up growth (CUG), there are adverse effects on human health. However, there is little information about its influence on bone metabolism. This study aimed to investigate the effects of leptin on bone metabolism and formation during high-fat diet (HFD)-induced CUG. We randomly divided male Wistar rats (5 weeks old) into four groups: control (CTL), caloric restriction and normal chow (RN), caloric restriction (4 weeks), and HFD (RH), and RH + leptin antagonist (RH + LEPA). We monitored body weights, biochemical markers, and epididymal and perirenal fat in these rats. We then performed Hematoxylin and Eosin (H&E) staining to evaluate bone metabolism. We detected osteoprotegerin (OPG) and receptor activator of nuclear factor-kappa b ligand (RANKL) by qRT-PCR and immunohistochemistry (IHC). We found that HFD increased the body weights in rats. In RN, RH, and RH + LEPA groups, major biochemical markers of bone metabolism in rat serum were significantly altered. We found that epididymal and perirenal fat tissues of RH and RH + LEPA groups were higher than those in the RN group. Severe bone formation impairment in the distal diaphysis and metaphysis of the left femora and lumbar vertebra was seen in the RH group compared to RN, which was even aggravated by a leptin antagonist. OPG in the left femora and lumbar vertebra was lower in RH than the RN group. The leptin antagonist decreased OPG during CUG in the RH group, whereas RANKL expression showed an opposite alteration. During HFD-induced CUG, bone formation was mediated by OPG and RANKL and was affected by the leptin content.

Sam68 mediates leptin signaling and action in human granulosa cells: possible role in leptin resistance in PCOS

INTRODUCTION

Polycystic ovary syndrome (PCOS) is a complex metabolic disorder associated with ovulatory dysfunction, hyperandrogenism, obesity, and insulin resistance, that leads to subfertility. Sam68 is an RNA-binding protein with signaling functions that is ubiquitously expressed, including gonads. Sam68 is recruited to leptin signaling, mediating different leptin actions.

OBJECTIVE

We aimed to investigate the role of Sam68 in leptin signaling, mediating the effect on aromatase expression in granulosa cells and the posible implication of Sam68 in the leptin resistance in PCOS.

MATERIALS AND METHODS

Granulosa cells were from healthy donors (n = 25) and women with PCOS (n = 25), within the age range of 20 to 40 years, from Valencian Infertility Institute (IVI), Seville, Spain. Sam68 expression was inhibited by siRNA method and overexpressed by expression vector. Expression level was analysed by qPCR and immunoblot. Statistical significance was assessed by ANOVA followed by different post-hoc tests. A P value of <0.05 was considered statistically significant.

RESULTS

We have found that leptin stimulation increases phosphorylation and expression level of Sam68 and aromatase in granulosa cells from normal donors. Downregulation of Sam68 expression resulted in a lower activation of MAPK and PI3K pathways in response to leptin, whereas overexpression of Sam68 increased leptin stimulation of signaling, enhancing aromatase expression. Granulosa cells from women with PCOS presented lower expression of Sam68 and were resistant to the leptin effect on aromatase expression.

CONCLUSIONS

These results suggest the participation of Sam68 in leptin receptor signaling, mediating the leptin effect on aromatase expression in granulosa cells, and point to a new target in leptin resistance in PCOS.

Mangiferin Relieves Lipopolysaccharide-Induced Injury by Up-Regulating miR-181a via Targeting PTEN in ATDC5 Cells

Background

Mangiferin (MF) was reported to possess anti-inflammatory activity. This investigation tried to probe into the underlying mechanism of MF in osteoarthritis.

Methods

ATDC5 cells were pretreated with series concentrations of MF (0.1, 1, 5, 10, 15, 20 μM) for 2 h and then were exposed to lipopolysaccharide (LPS) (5 μg/ml) for 12 h to construct the inflammatory injury model. The cell viability, productions of pro-inflammatory cytokines and enzymes were respectively measured by employing CCK-8 assay, western blot, ELISA, and quantitative reverse-transcription (qRT)-PCR. miR-181a expression was altered by employing cell transfection. Dichloro-dihydro-fluorescein diacetate (DCFH-DA) method was employed for detection of reactive oxygen species (ROS) generation. Dual luciferase activity assay was conducted for analyzing the relationship between miR-181a and PTEN. The underlying mechanism was determined by employing western blot.

Results

High doses of MF treatment (15 and 20 μM) noticeably induced inflammatory injury exhibiting as increased the productions of pro-inflammatory cytokines, enzymes and ROS, activated NF-κB pathway and deactivated PTEN/PI3K/AKT pathway in ATDC5 cells. Besides, MF treatment notably remitted LPS-induced inflammatory injury through deactivation of NF-κB pathway and activation of PTEN/PI3K/AKT pathway. PTEN was a target of miR-181a. Inhibition of miR-181a remarkably reversed MF-triggered impacts on ATDC5 cells.

Conclusion

MF attenuated LPS-induced inflammatory damage through miR-181a/PTEN axis and thereby inhibiting NF-κB pathway and activating PI3K/AKT pathway.

The effect of adipocyte-macrophage crosstalk in obesity-related breast cancer

Adipose tissue is the primary source of many pro-inflammatory cytokines in obesity. Macrophage numbers and pro-inflammatory gene expression are positively associated with adipocyte size. Free fatty acid and tumor necrosis factor-α involve in a vicious cycle between adipocytes and macrophages aggravating inflammatory changes. Thereby, M1 macrophages form a characteristic 'crown-like structure (CLS)' around necrotic adipocytes in obese adipose tissue. In obese women, CLSs of breast adipose tissue are responsible for both increase in local aromatase activity and aggressive behavior of breast cancer cells. Interlinked molecular mechanisms between adipocyte-macrophage-breast cancer cells in obesity involve seven consecutive processes: Excessive release of adipocyte- and macrophage-derived inflammatory cytokines, TSC1-TSC2 complex-mTOR crosstalk, insulin resistance, endoplasmic reticulum (ER) stress and excessive oxidative stress generation, uncoupled respiration and hypoxia, SIRT1 controversy, the increased levels of aromatase activity and estrogen production. Considering elevated risks of estrogen receptor (E2R)-positive postmenopausal breast cancer growth in obesity, adipocyte-macrophage crosstalk is important in the aforementioned issues. Increased mTORC1 signaling in obesity ensures the strong activation of oncogenic signaling in E2Rα-positive breast cancer cells. Since insulin and insulin-like growth factors have been identified as tumor promoters, hyperinsulinemia is an independent risk factor for poor prognosis in breast cancer despite peripheral insulin resistance. The unpredictable effects of adipocyte-derived leptin-estrogen-macrophage axis, and sirtuin 1 (SIRT1)-adipose-resident macrophage axis in obese postmenopausal patients with breast cancer are unresolved mechanistic gaps in the molecular links between the tumor growth and adipocytokines.