Low Serum Oxytocin Concentrations Are Associated with Painful Menstruation

The interplay of oxytocin and sex hormones

The neuropeptide oxytocin has historically been associated with reproduction and maternal behavior. However, more recent research has uncovered that oxytocin has a much wider range of roles in physiology and behavior. Despite the excitement surrounding potential therapeutical applications of intranasally administered oxytocin, the results of these intervention studies have been inconsistent. Various reasons for these mixed results have been proposed, which tend to focus on methodological issues, such as study design. While methodological issues are certainly important, emerging evidence suggests that the interaction between oxytocin and sex hormones may also account for these varied findings. To better understand the purpose and function of the interaction of oxytocin with sex hormones, with a focus on estrogens, progesterone, and testosterone, we conducted a comprehensive thematic review via four perspectives: evolutionary, developmental, mechanistic, and survival. Altogether, this synergistic approach highlights the critical function of sex hormone activity for accomplishing the diverse roles of oxytocin via the modulation of oxytocin release and oxytocin receptor activity, which is also likely to contribute to the heterogeneity of outcomes after oxytocin administration.

Validation of two immunoassays for oxytocin measurements in human saliva

The objective of this research was to develop and validate two immunoassays for oxytocin measurement in human saliva, one using a monoclonal and the other a polyclonal antibody against oxytocin, whose affinity for oxytocin was tested by an antibody mapping epitope analysis. These assays were analytically validated and used to compare oxytocin concentrations with those obtained with a commercial kit before and after the extraction or reduction/alkylation (R/A) treatments to saliva samples. The assays were also used to evaluate changes in salivary oxytocin concentrations following a physical effort and an induced psychological stress, which have previously been described as situations that cause an increase in salivary oxytocin. Both assays showed to be precise and accurate in the validation studies, and the antibodies used showed a defined binding region in case of the monoclonal antibody, whereas the polyclonal antibody showed binding events through all the oxytocin sequence. Although the monoclonal and polyclonal assays showed a positive correlation, they give results in a different range of magnitude. Both assays showed significant increases in oxytocin concentrations when applied after the physical effort and the psychological stress. This study shows that a variability in the reported values of oxytocin can occur depending on the assay and indicates that the use of different types of antibodies can give a different range of values when measuring oxytocin in saliva.

The Association of Reproductive Hormones During the Menstrual Period with Primary Dysmenorrhea

Objective

This study aimed to investigate the association of reproductive hormones with primary dysmenorrhea in Chinese women.

Methods

A case-control study was conducted and patients with primary dysmenorrhea and non-dysmenorrhea participants were recruited. Oxytocin, PGF2α, vasopressin, estriol and estradiol were respectively measured in plasma collected three to five days after menstruation. Restricted cubic spline and multiple logistic regression models were adopted to analyze the association between hormones and primary dysmenorrhea.

Results

There were 604 participants enrolled in our study including 300 patients with primary dysmenorrhea. After adjustment for the potential confounders, oxytocin levels (Q3: OR (95% CI) = 0.50 (0.27~0.95) (p=0.035); Q4: 0.34 (0.17~0.66) (p=0.001)) and PGF2α levels (Q3: 0.45 (0.24~0.87) (p=0.017); Q4: 0.43 (0.22~0.84) (p=0.013)) were respectively associated with an decreased risk of primary dysmenorrhea, but estradiol (Q2: 2.18 (1.13~4.19) (p=0.020); Q3: 2.17 (1.12~4.19) (p=0.022)) and vasopressin (Q3: 2.88 (1.48~5.63) (p=0.002); Q4: 3.20 (1.65~6.22) (p<0.001)) with an increased risk of primary dysmenorrhea, respectively. Among patients with primary dysmenorrhea, the higher estriol level was associated with higher frequent dysmenorrhea (Q2: 3.12 (1.32~7.34) (p=0.009); Q3: 4.97 (2.08~11.85) (p<0.001)) and always dysmenorrhea (Q2: 2.51 (1.03~6.11) (p=0.041); Q3: 3.10 (1.25~7.73) (p=0.015)). Similarly, high estriol levels were associated with the higher degree of pain significantly only when hormone levels were at a high level (Q3: 2.06 (1.03~4.18) (p=0.043)).

Conclusion

Higher serum vasopressin and estradiol concentrations as well as lower oxytocin and PGF2α levels were associated with higher risk of primary dysmenorrhea. Estrogen showed a reverse U-shape association on the frequency and degree of pain among patients with primary dysmenorrhea.

Scientific Knowledge Graph of Dysmenorrhea: A Bibliometric Analysis from 2001 to 2021

Purpose

This study aims to help researchers master the most active hotspots and trends quickly through bibliometric analysis in the field of dysmenorrhea.

Methods

We retrieved literature on Web of Science from 2001 to 2021, and bibliometric analysis software CiteSpace was used in combination with VOSviewer.

Results

We finally acquired 944 papers and an upward trend in articles continued in this field overall. Through the map, China contributed the most, followed by the USA and Turkey. For institutions, Beijing University of Chinese Medicine in China contributed the most, followed by National Yang-Ming University in Taiwan, China. Hsieh JC and Hellman KM were both the most prolific authors with 14 articles. Five major research groups, respectively, with Hsieh JC, Hellman KM, Zhu J, Liang F and Dun W were the key group. Dawood MY was the most dominant author and most frequently cited author. The Cochrane Database of Systematic Reviews Journal was the most productive, and the Fertility and Sterility Journal was the most cited. Advances in pathogenesis and management for primary dysmenorrhea written by Dawood MY was most cited and influential. Pathophysiology, the potential central mechanism, syndrome, evaluation index, diagnosis of adenomyosis-associated dysmenorrhea, treatment, etc., were the main trends and hotspots.

Conclusion

Dysmenorrhea research has received a lot of attention from scholars. Strengthening international cooperation may promote the development of this field. The pathophysiology of dysmenorrhea, its impact on public health and its treatment are current research hotspots and are likely to be the focus of future study.

The Long Way of Oxytocin from the Uterus to the Heart in 70 Years from Its Discovery

The research program on oxytocin started in 1895, when Oliver and Schafer reported that a substance extracted from the pituitary gland elevates blood pressure when injected intravenously into dogs. Dale later reported that a neurohypophysial substance triggers uterine contraction, lactation, and antidiuresis. Purification of this pituitary gland extracts revealed that the vasopressor and antidiuretic activity could be attributed to vasopressin, while uterotonic and lactation activity could be attributed to oxytocin. In 1950, the amino-acid sequences of vasopressin and oxytocin were determined and chemically synthesized. Vasopressin (CYFQNCPRG-NH₂) and oxytocin (CYIQNCPLG-NH₂) differ by two amino acids and have a disulfide bridge between the cysteine residues at position one and six conserved in all vasopressin/oxytocin-type peptides. This characterization of oxytocin led to the Nobel Prize awarded in 1955 to Vincent du Vigneaud. Nevertheless, it was only 50 years later when the evidence that mice depleted of oxytocin or its receptor develop late-onset obesity and metabolic syndrome established that oxytocin regulates energy and metabolism. Oxytocin is anorexigenic and regulates the lean/fat mass composition in skeletal muscle. Oxytocin's effect on muscle is mediated by thermogenesis via a pathway initiated in the myocardium. Oxytocin involvement in thermogenesis and muscle contraction is linked to Prader-Willi syndrome in humans, opening exciting therapeutic avenues.

Novel saliva biomarkers for stress and infection in pigs: Changes in oxytocin and procalcitonin in pigs with tail-biting lesions

There is a need for feasible and reliable measures to improve and evaluate production animal health and welfare. Oxytocin is a promising novel stress-related biomarker and procalcitonin may be a measure of sepsis. Both have potential for use in pigs and can be measured from saliva, which allows on-farm sampling with minimal impact on the animals. The current study sought to further validate these measures using a spontaneous situation that causes both stress and an increased risk for infections in pigs, namely a tail-biting outbreak. Grower pigs on a commercial farm belonging to three different phenotype groups were selected: control pigs from control pens (CC, N = 30), control pigs (CTB, N = 10), and pigs with tail lesions from pens with a tail-biting outbreak (LTB, N = 27). A single sample of saliva was collected from each pig and analysed for a range of biomarkers related to stress, infection, inflammation, and immune activation. Oxytocin tended to be higher in CC pigs than in LTB pigs, while cortisol was higher in CTB than CC pigs. Procalcitonin tended to be higher, and haptoglobin was higher in LTB than in CC pigs. Adenosine-deaminase levels were similar between phenotypes. These results provide further evidence for the link between stress and tail biting, and indicate that tail-biting lesions are potential routes for systemic spread of bacteria. Further research into saliva oxytocin as a stress biomarker and saliva procalcitonin as a sepsis biomarker in pigs is warranted.

Oxytocin in Women's Health and Disease

Oxytocin (OT) is a nonapeptide mainly produced in the supraoptic and paraventricular nuclei. OT in the brain and blood has extensive functions in both mental and physical activities. These functions are mediated by OT receptors (OTRs) that are distributed in a broad spectrum of tissues with dramatic sexual dimorphism. In both sexes, OT generally facilitates social cognition and behaviors, facilitates parental behavior and sexual activity and inhibits feeding and pain perception. However, there are significant differences in OT levels and distribution of OTRs in men from women. Thus, many OT functions in men are different from women, particularly in the reproduction. In men, the reproductive functions are relatively simple. In women, the reproductive functions involve menstrual cycle, pregnancy, parturition, lactation, and menopause. These functions make OT regulation of women's health and disease a unique topic of physiological and pathological studies. In menstruation, pre-ovulatory increase in OT secretion in the hypothalamus and the ovary can promote the secretion of gonadotropin-releasing hormone and facilitate ovulation. During pregnancy, increased OT synthesis and preterm release endow OT system the ability to promote maternal behavior and lactation. In parturition, cervix expansion-elicited pulse OT secretion and uterine OT release accelerate the expelling of fetus and reduce postpartum hemorrhage. During lactation, intermittent pulsatile OT secretion is necessary for the milk-ejection reflex and maternal behavior. Disorders in OT secretion can account for maternal depression and hypogalactia. In menopause, the reduction of OT secretion accounts for many menopausal symptoms and diseases. These issues are reviewed in this work.