Regulation and localization of vascular endothelial growth factor within the mammary glands during the transition from late gestation to lactation

Mammary gland, kidney and rumen urea and uric acid transporters of dairy cows differing in milk urea concentration

The milk urea concentration (MUC) serves as indicator of urinary nitrogen emissions, but at comparable crude protein (CP) intake, cows with high (HMU) and low (LMU) MUC excrete equal urea amounts. We hypothesized that urea and uric acid transporters and sizes of the kidney, mammary gland, and rumen account for these phenotypes. Eighteen HMU and 18 LMU Holstein dairy cows fed a low (LP) and normal (NP) CP diet were studied. Milk, plasma and urinary urea concentrations were greater with NP feeding, while plasma and urinary urea concentrations were comparable between phenotypes. Milk and plasma uric acid concentrations were higher with LP feeding but not affected by phenotype. The milk-urine uric acid ratio was greater in HMU cows. The mRNA expressions of the ruminal urea transporter SLC14A1 and AQP10, the mammary gland and rumen AQP3, and the mammary gland uric acid transporter ABCG2 were not affected by group or diet. Renal AQP10, but not AQP3, AQP7, and SLC14A2 expressions, and the kidney weights were lower in HMU cows. These data indicate that renal size and AQP10 limit the urea transfer from blood to urine, and that MUC determines if uric acid is more released with milk or urine.

In Utero Exposure to trans-10, cis-12 Conjugated Linoleic Acid Modifies Postnatal Development of the Mammary Gland and its Hormone Responsiveness

We previously showed that dietary trans-10, cis-12 conjugated linoleic acid (10,12 CLA) stimulates estrogen-independent mammary growth in young ovariectomized mice. Here we investigated the effects of in utero or postnatal exposure to cis-9, trans-11 (9,11 CLA) and 10,12 CLA on postnatal development of the mammary gland and its responsiveness to ovarian steroids. In the first experiment we fed dams different CLA prior to and during gestation, then cross fostered female pups onto control fed dams prior to assessing the histomorphology of their mammary glands. Pregnant dams in the second experiment were similarly exposed to CLA, after which their female pups were ovariectomized then treated with 17β-estradiol (E), progesterone (P) or E + P for 5 days. In a third experiment, mature female mice were fed different CLA for 28 days prior to ovariectomy, then treated with E, P or E + P. Our data indicate that 10,12 CLA modifies the responsiveness of the mammary glands to E or E + P when exposure occurs either in utero, or postnatally. These findings underline the sensitivity of the mammary glands to dietary fatty acids and reinforce the potential for maternal nutrition to impact postnatal development of the mammary glands and their risk for developing cancer.

Serum from patients with hypertension promotes endothelial dysfunction to induce trophoblast invasion through the miR‑27b‑3p/ATPase plasma membrane Ca2+ transporting 1 axis

Pregnancy‑induced hypertension is often accompanied by preeclampsia. The present study investigated whether microRNA (miR)‑27b‑3p affected the occurrence of preeclampsia by regulating the function of endothelial cells. Expressions levels of miR‑27b‑3p and ATPase plasma membrane Ca²⁺ transporting 1 (ATP2B1) were determined using reverse‑transcription quantitative PCR. miR‑27b‑3p targeting ATP2B1 was predicted using bioinformatics and further confirmed by dual‑luciferase reporter assays. Cell Counting Kit‑8, Transwell and Matrigel tube formation assays were performed to detect the effects of miR‑27b‑3p on proliferation, migration and tube formation of human umbilical vein endothelial cells (HUVECs), respectively. Moreover, HTR8/SVneos cells were co‑cultured with HUVECs to detect the invasion of trophoblast cells, and the expression levels of vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)‑2 and MMP‑9 of HUVECs and HTR8/SVneos were detected by western blotting. Expression levels of miR‑27b‑3p were upregulated in the serum of patients with hypertension and preeclampsia, which could target and regulate the expression of ATP2B1. The expression levels of miR‑27b‑3p were increased and those of ATP2B1 were reduced in HUVECs from hypertensive serums. Moreover, miR‑27b‑3p mimics reduced the expression level of ATP2B1, and miR‑27b‑3p inhibitor reversed the effect of hypertensive serum on ATP2B1 expression. Furthermore, patients with hypertension showed increased endothelial dysfunction, reduced trophoblastic invasion and the expressions of VEGF, MMP‑2 and MMP‑9, and miR‑27b‑3p mimics and silencing of ATP2B1 produced similar results to HUVECs. The miR‑27b‑3p inhibitor reversed the effect of hypertensive serum, and silencing of ATP2B1 inhibited the improvement of miR‑27b‑3p inhibitor to HUVECs and HTR‑8/SVneo cells in proliferation, migration and tube formation. The current findings suggested that miR‑27b‑3p promoted proliferation, migration and tube formation of HUVECs and enhanced invasion of trophoblast cells, via regulation of ATP2B1. Thus, miR‑27b‑3p could be considered as a molecular risk factor in the pathogenesis and development of preeclampsia.

Animal Models for In Vivo Lactation Studies: Anatomy, Physiology and Milk Compositions in the Most Used Non-Clinical Species: A Contribution from the ConcePTION Project

Simple Summary

Nowadays, the importance of breastfeeding has been very well recognized not only by the scientific world but also by public opinion. Such awareness has nonetheless put a lot of pressure on women under chronic pharmacological medication, or that simply need to alleviate common post-partum health issues, due to the lack of scientific data regarding the potential transfer to the offspring during lactation. In such a scenario, the ConcePTION project aims at creating a trusted ecosystem that can efficiently generate and disseminate reliable evidence-based information regarding the effects of medications used during pregnancy and breastfeeding to women and their healthcare providers. Due to the need for a reliable animal species to obtain scientific data, the present review summarizes the main features contributing to the lactation process in the most commonly used laboratory animal species.

Abstract

The present review aims to summarize the main features of mammary gland anatomy, and the physiology of lactation and colostrum/milk in the most commonly used animal species for regulatory toxicity. The final goal is the selection of a preferred animal species to be enrolled in studies investigating the potential transfer of drugs and exogenous molecules through milk, within the Innovative Medicines Initiative (IMI) funded project ConcePTION. Reference data regarding humans were also collected and analyzed in order to highlight critical similarities and differences with the studied species. Additional practical considerations were also taken into account, such as ethical consideration regarding the chosen species which affects the group size, financial implications and technical feasibility of lactation trials (e.g., ease of sampling, volume of sampling, husbandry requirements and scientific recognition). In conclusion, the present analysis of the literature confirms the complexity of the decisional process behind the choice of an animal model for in vivo trials. For some of the evaluated species, data were either poor or missing, highlighting the necessity to generate more physiological background studies for species that are routinely used in laboratory settings. Overall, when taking into consideration ethical factors, feasible group size, milk volume and ease of milk collection, and physiological similarities with humans, minipigs seem to represent the most appropriate choice.

Organization of mammary blood vessels as affected by mammary parenchymal region and estradiol administration in Holstein heifer calves

Mammary blood flow is central to mammary growth, development, and productivity, but the development of the vasculature network is poorly understood. The objective of this study was to determine how the vascular system adapts to mammary growth by inducing different levels of mammary growth and examining 2 regions of mammary parenchymal tissue. Holstein heifer calves (n = 12) received daily injections on the days immediately preceding euthanasia at 82 d of age. Treatments were control (CON), short-term estradiol (STE), and long-term estradiol (LTE). The CON calves received corn oil injections, the STE calves received 9 injections of corn oil followed by 3 injections of estradiol, and the LTE calves received 12 estradiol injections. Mammary tissues were collected from the center and edge parenchymal regions of all right rear mammary glands to quantify the tissue area of various tissue structures, the percentage of proliferating epithelial cells, and the number and form of blood vessels. Results showed that LTE calves had a greater tissue area occupied by epithelium than CON and STE calves, and the epithelial area in CON and STE calves was similar. Edge parenchyma had a greater percentage of proliferating epithelial cells than center parenchyma across all treatment groups. In the edge region, LTE calves had the greatest percentage of proliferating epithelial cells, coinciding with greater epithelial area. The number of blood vessels per unit of tissue area was greater in center than in edge parenchyma; the corresponding vessel surface area per unit of tissue area followed the same pattern. Mammary blood vessel measures were not markedly influenced by estradiol treatment. These results highlight the marked difference in the number and organization of blood vessels in different mammary parenchyma regions but indicate that the effects of estradiol on stimulating mammary epithelial proliferation does not directly translate to increasing numbers of blood vessels.

Folate Deficiency Inhibits Development of the Mammary Gland and its Associated Lymphatics in FVB Mice

BACKGROUND

Folate is essential for DNA synthesis, DNA repair, cell proliferation, development, and morphogenesis. Folic acid (FA) is a nutritional supplement used to fortify human diets.

OBJECTIVES

We investigated the effects of dietary FA on early mammary gland (MG) development and hyperplasia.

METHODS

Study 1: nulliparous female FVB wild-type (WT) mice were fed control (Con; 2 mg FA/kg), deficient (Def; 0 mg FA/kg), excess (Ex; 5 mg FA/kg), or super excess (S-Ex; 20 mg FA/kg) diets for 8 wk before mating to WT or heterozygous FVB/N-Tg[mouse mammary tumor virus long terminal repeat (MMTV)-polyomavirus middle T antigen (PyVT)]634Mul/J (MMTV-PyMT+/-) transgenic males. Dams were fed these diets until they weaned WT or MMTV-PyMT+/- pups, which were fed the dam's diet from postnatal day (PND) 21 to 42. Tissues were collected from female progeny at PNDs 1, 21, and 42. Study 2: Con or Def diets were fed to WT intact females and males from PND 21 to 56, or to ovariectomized females from PND 21 to 77; tissues were collected at PND 56 or 77. Growth of all offspring, development of MGs, MG hyperplasia, supramammary lymph nodes, thymus and spleen, cell proliferation, and expression of MG growth factors were measured.

RESULTS

Study 1: Ex or S-Ex did not affect postnatal MG development or hyperplasia. The rate of isometric MG growth (PND 1-21) was reduced by 69% in Def female progeny (P < 0.0001). Similarly, hyperplastic growth in MGs of Def MMTV-PyMT+/- offspring was 18% of Con (P < 0.05). The Def diet reduced supramammary lymph node size by 20% (P < 0.0001) and increased MG insulin-like growth factor 2 mRNA by 200% (P < 0.05) and protein by 130%-150% (P < 0.05). Study 2: the Def diet did not affect MG growth, but it did reduce supramammary lymph node size (P < 0.05), spleen weight (P < 0.001), and thymic medulla area (P < 0.05).

CONCLUSIONS

In utero and postnatal folate deficiency reduced the isometric development of the MGs and early MG hyperplasia. Postnatal folate deficiency reduced the development of lymphatic tissues.

Effects of sustained hyperprolactinemia in late gestation on mammary development of gilts

The objective of this project was to determine the effects of sustained hyperprolactinemia for 7 or 20 d on mammary development in late-pregnant gilts. On day 90 of gestation, gilts were assigned to one of 3 groups to receive intramuscular (IM) injections of (1) canola oil (CTL, n = 18) until day 109 ± 1 of gestation; (2) a dopamine receptor antagonist, domperidone (0.5 mg/kg of body weight [BW]) until day 96 ± 1 of gestation (T7, n = 17); or (3) domperidone (0.5 mg/kg BW) until day 109 ± 1 of gestation (T20, n = 17). Domperidone-treated gilts also received 100 mg of domperidone per os twice daily from days 90 to 93 of gestation. Blood was sampled on days 89, 97, 104, and 110 for prolactin (PRL), insulin-like growth factor 1 (IGF1), lactose, urea, and glucose assays. Mammary glands were collected at necropsy, on day 110, for compositional and cell proliferation analyses. Abundance of mRNA for selected genes was also determined in the mammary gland and the pituitary gland. On day 97 of gestation, PRL concentrations were 3 times greater for T20 and T7 than CTL gilts and were also greater for T20 than T7 and CTL gilts on days 104 and 110 (P < 0.001). Concentrations of IGF1 in T20 and T7 gilts were elevated relative to controls on days 97 and 104 and were greater for T20 vs T7 and CTL gilts on day 110 (P < 0.05). There were no treatment effects (P > 0.1) on parenchymal or extraparenchymal tissue weights, or on epithelial proliferation as measured by immunohistochemistry for Ki-67. Treatments did not alter concentrations of dry matter (DM), fat, or DNA (P > 0.1) in parenchyma. Concentrations of RNA (P < 0.05) and protein (P < 0.10) as well as total parenchymal protein, RNA, and DNA (P < 0.05) were lower, or tended to be, in T20 than T7 or CTL gilts. Hyperprolactinemia for 20 d in late gestation increased mRNA abundance of the milk protein genes beta-casein (CSN2) and whey acidic protein (WAP) (P < 0.05) in mammary parenchyma and also decreased mRNA abundance of the long form of the prolactin receptor (PRLR-LF). Increasing PRL concentrations for 7 or 20 d in late gestation had no beneficial effects on the composition of the mammary gland, and sustained exposure to domperidone for 20 d reduced metabolic activity either by a lower expression of the long form of the PRL receptor in mammary parenchymal tissue or, most likely, by the early involution of parenchymal tissue. In conclusion, results do not support the hypothesis that a sustained hyperprolactinemia in late gestation could enhance mammary development of gilts.

Cross talk of vascular endothelial growth factor and neurotrophins in mammary gland development

During the period of lactation, there is extensive growth and development of the mammary gland in order to fulfil the increased demands of milk for the growing infant. Angiogenesis plays a key role in alveolar development and facilitates optimal milk production. Vascular endothelial growth factor (VEGF) is one of the key growth factors regulating angiogenesis in mammary gland. Apart from VEGF, neurotrophins are also known to regulate angiogenesis through direct or indirect mechanisms. Few studies have demonstrated mRNA levels of neurotrophins and their receptors in mammary gland both in humans and rodents. A cross talk between VEGF and neurotrophins has been described in placental development. The enteric and central nervous system are not fully developed at birth, making it imperative to have appropriate levels of angiogenic factors and neurotrophins during postnatal period. The current review summarises studies which describe the role of neurotrophins and angiogenic factors in the mammary gland development.

Hypoalbuminemia: Pathogenesis and Clinical Significance

Hypoalbuminemia is associated with inflammation. Despite being addressed repeatedly in the literature, there is still confusion regarding its pathogenesis and clinical significance. Inflammation increases capillary permeability and escape of serum albumin, leading to expansion of interstitial space and increasing the distribution volume of albumin. The half‐life of albumin has been shown to shorten, decreasing total albumin mass. These 2 factors lead to hypoalbuminemia despite increased fractional synthesis rates in plasma. Hypoalbuminemia, therefore, results from and reflects the inflammatory state, which interferes with adequate responses to events like surgery or chemotherapy, and is associated with poor quality of life and reduced longevity. Increasing or decreasing serum albumin levels are adequate indicators, respectively, of improvement or deterioration of the clinical state. In the interstitium, albumin acts as the main extracellular scavenger, antioxidative agent, and as supplier of amino acids for cell and matrix synthesis. Albumin infusion has not been shown to diminish fluid requirements, infection rates, and mortality in the intensive care unit, which may imply that there is no body deficit or that the quality of albumin “from the shelf” is unsuitable to play scavenging and antioxidative roles. Management of hypoalbuminaemia should be based on correcting the causes of ongoing inflammation rather than infusion of albumin. After the age of 30 years, muscle mass and function slowly decrease, but this loss is accelerated by comorbidity and associated with decreasing serum albumin levels. Nutrition support cannot fully prevent, but slows down, this chain of events, especially when combined with physical exercise.

Hyperprolactinaemia - a problem in patients from the reproductive period to the menopause

Hyperprolactinaemia especially affects women in reproductive age (90/100,000) but also often is diagnosed in menopause age and leads to disturbances in functioning of LH-RH neurons and, as a consequence, to a decrease of FSH and LH, which causes inhibition of oestradiol production. Prolactin is a peptide hormone, phylogenetically one of the oldest, stimulating cells of various organs, which is produced and secreted mainly by lactotrophic acidophilic cells of the anterior lobe of the pituitary. It influences the increase in the mass of the mammary glands, and stimulation and maintenance of lactation after delivery. There are a number of factors apart of pregnancy, delivery, and lactation than can influence secretion of the hormone in other physiological and pathological circumstances, like high-protein diet, stress, REM sleep, or neoplastic tumours, inflammatory diseases, chronic systematic diseases, thyroid hormonal changes, and drug intake. The purpose of this review is to summarise the current knowledge regarding the proper diagnosis and possible influence of hyperprolactinaemia on fertility and menopause symptoms and current treatment methods.

Vascular endothelial growth factor (VEGFA) gene variation in polycystic ovary syndrome in a Tunisian women population

BACKGROUND

Polycystic ovary syndrome (PCOS) is characterized by the growth of a number of small cysts on the ovaries which leads to sex hormonal imbalance. Women who are affected by this syndrome suffer from irregular menstrual cycles, decline in their fertility, excessive hair growth, obesity, acne and most importantly cardiac function problems. The vascular endothelial growth factor (VEGF) plays a pivotal role in tissue vascularization in general and in the pathogenesis of many diseases. The PCOS was found to be associated with high expression levels of VEGF. In women who undergo assisted reproductive procedures (ART), VEGF was found to be a key mediator of other factors to control ovary angiogenesis. Here, we set out to examine the association of VEGFA gene polymorphism with PCOS and its components in a population of Tunisia women to enhance our understanding of the genetic background leading angiogenesis and vascularization abnormalities in PCOS.

METHODS

The association of VEGFA gene with PCOS and its components was examined in a cohort of 268 women from Tunisia involving 118 PCOS patients and 150 controls. VEGFA gene variations were assessed through the analysis of the following SNPs rs699947 (A/C), rs833061 (C/T), rs1570360 (G/A), rs833068 (G/A), rs3025020 (C/T), and rs3025039 (C/T). The linkage disequilibrium between SNPs was assessed using HAPLOVIEW software while combination of SNPs into haplotypes in the population and the reconstruction of the cladogram were carried-out by PHASE and ARLEQUIN programs, respectively. Genetic association and genotype-phenotype correlations were calculated by logistic regression and non-parametric tests (Kruskall-Wallis and Mann-Whitney tests), respectively, using StatView program.

RESULTS

We observed 10 haplotypes in our studied cohort whereH1 (ACGG), H2 (ACAG), H7 (CTGG) and H8 (CTGA) were the most frequent. We observed the association of the genotype CT of the SNP rs30225039 with PCOS phenotype (P = 0.03; OR 95 % CI = 2.05 [1.07-3.90]) and a trend for correlation of the pair of haplotypes H2/H2 with prolactin levels in plasma (P = 0.077; 193.5 ± 94.3 vs 45.7 ± 7.2). These data are consistent with literature and highlight one more time the role of vascularization in the pathogeny of PCOS.

CONCLUSIONS

LD pattern in VEGF locus showed a similar LD pattern between the Tunisian population and the CEU. More haplotypes in the Tunisian population than in CEU was observed (22 haplotypes vs 16 haplotypes) suggesting higher recombination rate in Tunisians. The study showed that there was any advantage of using haplotypes compared with SNPs taken alone.