Ultrasonic assessment of variations in thickness of subcutaneous fat during the normal menstrual cycle

Newborn and elderly skin: two fragile skins at higher risk of pressure injury

Skin is a key organ maintaining internal homeostasis by performing many functions such as water loss prevention, body temperature regulation and protection from noxious substance absorption, microorganism intrusion and physical trauma. Skin ageing has been well studied and it is well known that physiological changes in the elderly result in higher skin fragility favouring the onset of skin diseases. For example, prolonged and/or high-intensity pressure may suppress local blood flow more easily, disturbing cell metabolism and inducing pressure injury (PI) formation. Pressure injuries (PIs) represent a significant problem worldwide and their prevalence remains too high. A higher PI prevalence is correlated with an elderly population. Newborn skin evolution has been less studied, but some data also report a higher PI prevalence in this population compared to older children, and several authors also consider this skin as physiologically fragile. In this review, we compare the characteristics of newborn and elderly skin in order to determine common features that may explain their fragility, especially regarding PI risk. We show that, despite differences in appearance, they share many common features leading to higher fragility to shear and pressure forces, not only at the structural level but also at the cellular and molecular level and in terms of physiology. Both newborn and elderly skin have: (i) a thinner epidermis; (ii) a thinner dermis containing a less-resistant collagen network, a higher collagen III:collagen I ratio and less elastin; (iii) a flatter dermal-epidermal junction (DEJ) with lower anchoring systems; and (iv) a thinner hypodermis, resulting in lower mechanical resistance to skin damage when pressure or shear forces are applied. At the molecular level, reduced expression of transforming growth factor β (TGFβ) and its receptor TGFβ receptor II (TβRII) is involved in the decreased production and/or increased degradation of various dermal extracellular matrix (ECM) components. Epidermal fragility also involves a higher skin pH which decreases the activity of key enzymes inducing ceramide deficiency and reduced barrier protection. This seems to be correlated with higher PI prevalence in some situations. Some data also suggest that stratum corneum (SC) dryness, which may disturb cell metabolism, also increases the risk of PI formation. Besides this structural fragility, several skin functions are also less efficient. Low applied pressures induce skin vessel vasodilation via a mechanism called pressure-induced vasodilation (PIV). Individuals lacking a normal PIV response show an early decrease in cutaneous blood flow in response to the application of very low pressures, reflecting vascular fragility of the skin that increases the risk of ulceration. Due to changes in endothelial function, skin PIV ability decreases during skin ageing, putting it at higher risk of PI formation. In newborns, some data lead us to hypothesize that the nitric oxide (NO) pathway is not fully functional at birth, which may partly explain the higher risk of PI formation in newborns. In the elderly, a lower PIV ability results from impaired functionality of skin innervation, in particular that of C-fibres which are involved in both touch and pain sensation and the PIV mechanism. In newborns, skin sensitivity differs from adults due to nerve system immaturity, but the role of this in PIV remains to be determined.

Measures of body composition via Dual-energy X-ray absorptiometry, ultrasound and skinfolds are not impacted by the menstrual cycle in active eumenorrheic females

OBJECTIVES

(1) Compare changes in body composition estimates over the menstrual cycle in active females using Dual-energy X-ray absorptiometry, standardised brightness-mode ultrasound and skinfolds (2) Compare the predictability of Dual-energy X-ray absorptiometry fat mass estimate via standardised brightness-mode ultrasound versus skinfolds measurements.

DESIGN

Thirty active females (27 ± 5 y) with regularly occurring menstrual cycles participated in a cross sectional study.

METHODS

Participants completed four assessment sessions scheduled according to each individual's menstrual cycle. These sessions took place during their (1) early follicular, (2) mid-to-late follicular, (3) mid-luteal and (4) second early follicular phases. Body composition estimates were acquired using Dual-energy X-ray absorptiometry, subcutaneous adipose tissue thickness was measured at eight sites using standardised brightness-mode ultrasound and skinfolds.

RESULTS

The sum of eight subcutaneous adipose tissue thickness measured using standardised brightness-mode ultrasound and skinfolds were not different between the cycle phases (p > 0.05). Body mass and Dual-energy X-ray absorptiometry total mass estimate as well as Dual-energy X-ray absorptiometry estimates of total and regional lean and fat mass were also not different between cycle phases (p > 0.05) and any changes were within the 95% confidence intervals of their respective least significant change values.

CONCLUSIONS

There were no true and meaningful changes in the sum of eight subcutaneous adipose tissue thickness measured via standardised brightness-mode ultrasound and skinfolds or Dual-energy X-ray absorptiometry total and regional tissue mass estimates across the menstrual cycle in active eumenorrheic females. Body composition may thus be assessed via these methods in this population at any cycle phase with standardised participant presentation.

The acute effect of the menstrual cycle and oral contraceptive cycle on measures of body composition

PURPOSE

This study aimed to investigate the effect of fluctuating female hormones during the menstrual cycle (MC) and oral contraceptive (OC) cycle on different measures of body composition.

METHODS

Twenty-two women with a natural MC and thirty women currently taking combined monophasic OC were assessed over three phases of the menstrual or oral contraceptive cycle. Body weight, skinfolds, bioelectric impedance analysis (BIA), ultrasound, dual-energy X-ray absorptiometry (DXA), and peripheral quantitative computed tomography (pQCT) measurements were performed to assess body composition. Urine specific gravity (USG) was measured as an indication of hydration, and serum oestradiol and progesterone were measured to confirm cycle phases.

RESULTS

Five participants with a natural MC were excluded based on the hormone analysis. For the remaining participants, no significant changes over the MC and OC cycle were found for body weight, USG, skinfolds, BIA, ultrasound and pQCT measures. However, DXA body fat percentage and fat mass were lower in the late follicular phase compared to the mid-luteal phase of the MC, while for the OC cycle, DXA body fat percentage was higher and lean mass lower in the early hormone phase compared with the late hormone phase.

CONCLUSION

Our findings suggest that assessment of body fat percentage through BIA and skinfolds may be performed without considering the MC or OC cycle. Body adiposity assessment via DXA, however, may be affected by female hormone fluctuations and therefore, it may be advisable to perform repeat testing using DXA during the same phase of the MC or OC cycle.

How reliably can ultrasound help determine muscle and adipose tissue thickness in clinical settings? An assessment of intra- and inter-examiner reliability in the USVALID study

BACKGROUND/OBJECTIVES

Ultrasound is used to measure muscle and adipose tissue thickness at the bedside. This study was aimed at determining the intra- and inter-examiner reliability for marking points to measure adipose tissue and muscle thickness and assessing it in terms of the performance and evaluation of the corresponding ultrasound scans.

SUBJECTS/METHODS

Intra- and inter-examiner reliability was tested in 120 patients. Limb lengths were measured to mark three and two measuring points on both the thighs and upper arms, respectively. Ultrasound scans were performed at each measuring point to evaluate muscle and adipose tissue thickness.

RESULTS

Regarding the marking of the measuring points, intra- and inter-examiner reliability were high to very high, with correlation coefficients ranging from 0.74 to 0.96. In the performance and evaluation of adipose tissue thickness, all measuring points showed a high to very high reliability, with correlation coefficients ranging from 0.70 to 0.97. In the performance and evaluation of muscle thickness, the ventral measuring point on the thigh and the anterior measuring point on the upper arm showed the best reliability, with high to very high correlation coefficients ranging from 0.77 to 0.93.

CONCLUSIONS

In terms of intra- and inter-examiner reliability, the ventral measuring point on the thigh and the anterior measuring point on the upper arm can be strongly recommended for ultrasound measurements of muscle and adipose tissue thickness.

Self-perceived and objective measurements of facial puffiness in Chinese women

BACKGROUND

Facial puffiness, caused by mild or normal fluid retention, commonly experienced by women, may not pose a health risk, but it can be a cause of cosmetic concern. The objectives of this study were to determine whether self-perceived facial puffiness can be measured objectively.

MATERIALS AND METHODS

A total of 151 Chinese women between 20 and 68 years of age were recruited. Facial water content, skin thickness, and elasticity were measured at two time points within a day (visit one occurred when the participants perceived they had facial puffiness; visit two occurred when the participants perceived their facial puffiness had subsided). Participants were also given a rating scale to self-evaluate their puffiness and firmness at different regions of the face.

RESULTS

The participants could perceive a difference in facial puffiness between the two visits. Water content and skin thickness were significantly higher in all regions of the face for all participants during the first visit. Skin elasticity was also significantly different between visits one and two. There was a significant increase in water content and skin thickness in the lower eyelid region in women who were older than 40 years.

CONCLUSION

This is the first study to show that self-perceived facial puffiness can be measured objectively and that skin elasticity can change significantly when facial puffiness subsides.

Untargeted Metabolomic Approach Shows No Differences in Subcutaneous Adipose Tissue of Diabetic and Non-Diabetic Subjects Undergoing Bariatric Surgery: An Exploratory Study

BACKGROUND

Obesity plays a major role in the development of insulin resistance (IR) and diabetes (T2DM). Increased adipose tissue (AT) is particularly of interest because it activates a chronic inflammatory response in adipocytes and other tissues. AT plays key endocrine and metabolic functions, acting in the regulation of insulin sensitivity and energy homeostasis. Additionally, it can be easily collected during bariatric surgery. The purpose of this pilot study was to explore the potential differences in AT metabolism, through comparing the untargeted metabolomic profiles of diabetic and non-diabetic obese patients undergoing bariatric surgery.

METHODS

For this exploratory study, samples were collected from 17 subjects. Subcutaneous AT (SAT) samples from obese-diabetic (n = 8) and Obese-non-Diabetic (n = 9) subjects were obtained from the Human Metabolic Tissue Bank. Untargeted metabolomic profiling was performed by Metabolon® Inc. Statistical analysis was performed using the MetaboAnalyst 4.0 platform.

RESULTS

Among the 421 metabolites identified and analyzed there were no significant differences between the Obese-Diabetics and the Obese-non-Diabetics. Small changes were observed by fold change analysis mainly in lipid (n = 12; e.g. NEFAs) and amino acid (n = 8; e.g. BCAAs) metabolic pathways. Dysregulation of these metabolites has been associated with IR and other T2DM-related pathophysiological processes.

CONCLUSION

Obesity may influence SAT metabolism masking T2DM-dependent dysregulation. Better understanding the metabolic differences within SAT in diabetic populations may help identify potential biomarkers for diagnosis and monitoring of T2DM in patients undergoing bariatric surgery.

Effects of supervised aerobic and strength training in overweight and grade I obese pregnant women on maternal and foetal health markers: the GESTAFIT randomized controlled trial

BACKGROUND

During pregnancy, a sedentary lifestyle may have negative consequences on maternal and foetal health status. The main objective of this project is to assess the effects of an exercise intervention in overweight and grade I obese pregnant on maternal and foetal health markers.

METHODS/DESIGN

The present study aims to recruit 60 overweight and grade I obese women interested in participating in an exercise intervention program from the 17th gestational week until delivery. Women will be randomized to either an exercise (three 60-min sessions/week of combined aerobic and strength training and pelvic floor exercises), or usual care (control) group (30 women per group). The primary outcome measures are maternal weight gain, and maternal and neonatal glycaemic profile. Secondary outcome measures are: i) perinatal obstetric records; i) body composition; iii) dietary patterns; iv) physical fitness; v) low-back pain; vi) objectively measured physical activity and sedentary behaviour; vii) haematology and biochemical analyses; viii) oxidative stress; ix) pro- and anti-inflammatory markers; x) bone health biomarkers; xi) sleep quality; xii) mental health, quality of life and positive health.

DISCUSSION

The findings of this project will help to identify strategies for primary prevention and health promotion based on this exercise-based intervention program among overweight and grade I obese pregnant women.

TRIAL REGISTRATION

NCT02582567 ; Date of registration: 20/10/2015.

Automatic measurement of human subcutaneous fat with ultrasound

This paper presents an approach to measure human subcutaneous fat thickness automatically using ultrasound radio frequency (RF) signals. We propose using spatially compounded spectrum properties extracted from the RF signals of ultrasound for the purpose of fat boundary detection. Our fat detection framework consists of 4 main steps. The first step is to capture RF data from 11 ultrasound beam angles and at 4 different focal positions. Second, spectrum dispersion is calculated from the local spectrum of RF data using the short-time Fourier transform and moment analysis. The values of the spectrum dispersion are encoded as gray-scale parametric images. Third, averaging is used to reduce speckle noise in the parametric image and improve the visualization of the subcutaneous fat layer. Finally, we apply Rosin's thresholding and random sample consensus boundary detection to extract the fat boundary. Our method was applied on 36 samples obtained in vivo at the suprailiac, thigh, and triceps of 9 human participants. In our study, high correlations between the manual and automatic ultrasound measurements (r > 0.7 at all body sites), and between the skinfold caliper and automatic ultrasound measurements (r > 0.7 at all body sites) were observed.

Physiological changes associated with the menstrual cycle: a review

The cyclic hormonal changes that regulate the menstrual cycle are a significant biological influence on the female body, one with both physical and emotional ramifications. Menstruation is governed by tightly orchestrated changes in the levels of ovarian estrogen and progesterone, which produce varying responses in diverse tissues and organs. The skin, the largest organ in the body, is replete with estrogen receptors (in both dermis and epidermis) and to a lesser extent, progesterone receptors. Cyclically fluctuating levels of estrogen and progesterone influence numerous characteristics of the epidermis, including skin surface lipid secretion and sebum production, skin thickness, fat deposition, skin hydration, and barrier function. Dermal collagen content, which contributes to skin elasticity and resistance to wrinkling, is also influenced. Interestingly, estrogen levels also influence skin pigmentation and UV susceptibility, as well as resident microflora. In addition, changing hormone levels across the menstrual cycle produce measurable variations in immune function and disease susceptibility. An understanding of the profound influence that fluctuating estrogen and progesterone levels have on the biological responses of the premenopausal adult woman is critical to optimizing the efficacy of medical therapies in this population.

Morphometric and hormonal changes during the chimpanzee menstrual cycle

BACKGROUND

Sex steroids affect many peripheral tissue sites in female mammals. Receptors for these hormones have been found in skin, fat, and bone. In women, these tissues can show morphological changes during the menstrual cycle that may be directly related to steroid secretion.

METHODS

The present study was done on chimpanzees to document morphometric markers associated with these tissues (anogenital swelling volume, skin fold thickness as indicator of subcutaneous fat, bony diameters of mandible, wrist, and elbow) and to compare them with cyclic patterns of estradiol, progesterone, testosterone, gonadotropins, and prolactin.

RESULTS

Swelling volume changed significantly over the menstrual cycle. All other morphometric parameters showed variation without statistical significance. Skin folds were thickest during the luteal phase. Bony diameters displayed similar but less distinctive changes. Testosterone correlated positively with diameter sites, inversely with subcutaneous fat. No relationships with either estradiol or progesterone were found. We assume that subcutaneous fat and morphometric bone parameters exhibit cycle-dependent changes that may be caused by changes in steroid secretion.

L’adipocyte dans une histoire d’amincissant

Nowadays, in industrialised societies, it is fashionable for women to be slim. However, throughout history, this has not always been the case, especially as "cellulite" (cellulitis) was full of typically feminine symbols. The ideal feminine silhouette has changed with the rhythm of cultures. Cellulitis is an inappropriate term used by women to describe curves which they judge to be too plump and not very aesthetic, mostly around the thighs and hips. This lipodystrophy of the adipose tissue represents approximately 25% of a woman's body weight. It is clinically characterised by an "orange peel" skin surface, which is a result of the excessive development of the volume of the adipocytes organised in lobules within the walls of the unstretchable conjunctive tissue. This phenomenon is associated with an insufficiency of the venous tonus and an increase in the capillary permeability, which both contribute to an increase in the infiltration of water in the tissue. In reality, the understanding of cellulite has truly progressed with research based on adipocyte functions. An adipocyte is a metabolically active cell which plays a central role in the control of the energetic balance of the organism. In order to assume this role, it possesses all the enzymatic equipment necessary for synthesis (lipogenesis) and for triglyceride storage, mobilisation and liberation as free fatty acids (lipolysis). During these last few years, as well as this role as an energetic reserve which manages lipogenesis/lipolysis balance, the adipocyte has acquired the status of an endocrine and paracrine cell through the identification of numerous secreted factors. When we look back at the history of slimming products launched on the market since the 1980's, we can notice the role of the adipocyte tool and understand its functions in the choice of active ingredients, the development of complementary actions, the importance of the texture, the evolution of methods used to evaluate the efficacy on human volunteers and of course, we must not forget the women satisfaction and the power of seduction through words.