Advanced glycation products’ levels and mechanical properties of vaginal tissue in pregnancy

Assessment of perineal body properties in women with stress urinary incontinence using Transperineal shear wave elastography

Limited data on the correlation between the perineal body (PB) and stress urinary incontinence (SUI) are available. The objectives of this study were to quantify the PB using shear wave elastography (SWE) technology with a high-frequency linear array probe to evaluate the relationship between the properties of PB and stress urinary incontinence (SUI). This study included 64 women with SUI and 70 female control participants. The length, height, perimeter, and area of PB in all participants were calculated using transperineal ultrasound, and the elasticity of PB was assessed by SWE at rest and during the maximal Valsalva maneuver, respectively. In addition, the comparison of PB parameters between the patients with SUI and the healthy participants was conducted. The transperineal ultrasound and SWE examination was performed in 134 participants, and the elastic modulus values were significantly increased from participants at rest to those during the maximal Valsalva maneuver in all participants (Emax: 35.59 versus 53.13 kPa, P < 0.001; and Emean: 26.97 versus 40.25 kPa, P < 0.001). Emax and Emean of PB exhibited significant differences during the maximal Valsalva maneuver between the SUI group and the control group (47.73 versus 58.06 kPa, P < 0.001; and 35.78 versus 44.33 kPa, P < 0.001) and had a negative correlation with SUI. The BMI and PB height during the maximal Valsalva maneuver in the SUI group were found to be significantly higher than that in healthy volunteers. Emax and Emean of PB negatively correlated with BMI during the maximal Valsalva maneuver (r = -0.277, P = 0.001 and r = -0.211, P = 0.014). ROC curve analysis demonstrated that PB perimeter of less than 12.68mm was strongly associated with SUI during the maximal Valsalva maneuver, and an Emax of less than 55.76 kPa had a 100% specificity in predicting SUI. SWE can quantify the elasticity of PB, identifying a significant difference between participants at rest and during Valsalva maneuver. In addition, the stiffness of the PB was significantly lower in women with SUI than in healthy women, which may provide a noninvasive clinical practice in SUI prediction.

Possible effects of dietary advanced glycation end products on maternal and fetal health: a review

Excessive accumulation of advanced glycation end products (AGEs) in the body has been associated with many adverse health conditions. The common point of the pathologies associated at this point is oxidative stress and inflammation. Pregnancy is an important period in which many physiological, psychological, and biological changes are experienced. Along with the physiological changes that occur during this period, the mother maintaining an AGE-rich diet may cause an increase in the body's AGE pool and may increase oxidative stress and inflammation, as seen in healthy individuals. Studies have reported the negative effects of maternal AGE levels on maternal and fetal health during pregnancy. Although gestational diabetes, preeclampsia, endothelial dysfunction, and pelvic diseases constitute maternal complications, a number of pathological conditions such as intrauterine growth retardation, premature birth, neural tube defect, neurobehavioral developmental disorders, fetal death, and neonatal asphyxia constitute fetal complications. It is thought that the mechanisms of these complications have not been confirmed yet and more clinical studies are needed on this subject. The possible effects of dietary AGE levels during pregnancy on maternal and fetal health are examined in this review.

Time-dependent mechanical behaviour of the aortic chronic dissection flap

OBJECTIVES

The transition of aortic dissection from acute to chronic is poorly understood. We examined time-dependent mechanical behaviour and biochemical properties of chronic dissection tissues.

METHODS

Aorta samples were obtained from 14 patients with mixed aetiology who were undergoing elective surgery for chronic dissected aneurysms, ranging from 3 months to 15 years post-dissection. The tissue elastic modulus and tissue deformation following application of loading for 5 h were measured for the false lumen (FL), true lumen (TL) and flap (FP) tissues with a custom-indentation technique. Collagen, elastin and glycosaminoglycan levels were determined with established biochemical assays. Elastin fragmentation was graded from histological sections. The number of tissues characterized was as follows: FP (n = 10), TL (n = 5 for biomechanical testing, n = 8 for biochemical analysis, n = 8 for histological assessment) and FL (n = 4).

RESULTS

Tissues stiffness was highest in FP [59.8 (14.8) kPa] as compared with TL [50.7 (6.2) kPa] and FL [40.5 (4.7) kPa] (P = 0.023 and P = 0.006, respectively). FP [0.5 (0.08) mm] also exhibited reduced deformation relative to TL [0.7 (0.02) mm] and FL [0.9 (0.08) mm] (P = 0.003 and P = 0.006, respectively), lowest collagen concentration [FP: 40.1 (19.6) µg/mg, TL: 59.9 (19.5) µg/mg, P = 0.008; FL: 79.1 (32.0) µg/mg, P = 0.006] and the lowest collagen: elastin ratio [0.4 (0.1)] relative to the other tissues [TL; 0.6 (0.3), P = 0.006, FL; 1.5 (0.4); P = 0.003]. Significant elastin loss was evident in the FL-stained tissue sections whereas highly aligned, long fibres were visible in the FP and TL. A linear relationship was found between the stiffness, deformation and the time from the dissection event to surgical intervention for the FP. All data are presented as median (interquartile range).

CONCLUSIONS

FP exhibited reduced time-dependent deformation and distinct biochemical properties relative to TL and FL irrespective of connective tissue disorder or the anatomical region of the dissection.

Investigation of Murine Vaginal Creep Response to Altered Mechanical Loads

The vagina is a viscoelastic fibromuscular organ that provides support to the pelvic organs. The viscoelastic properties of the vagina are understudied but may be critical for pelvic stability. Most studies evaluate vaginal viscoelasticity under a single uniaxial load; however, the vagina is subjected to dynamic multiaxial loading in the body. It is unknown how varied multiaxial loading conditions affect vaginal viscoelastic behavior and which microstructural processes dictate the viscoelastic response. Therefore, the objective was to develop methods using extension-inflation protocols to quantify vaginal viscoelastic creep under various circumferential and axial loads. Then, the protocol was applied to quantify vaginal creep and collagen microstructure in the fibulin-5 wildtype and haploinsufficient vaginas. To evaluate pressure-dependent creep, the fibulin-5 wildtype and haploinsufficient vaginas (n = 7/genotype) were subjected to various constant pressures at the physiologic length for 100 s. For axial length-dependent creep, the vaginas (n = 7/genotype) were extended to various fixed axial lengths then subjected to the mean in vivo pressure for 100 s. Second-harmonic generation imaging was performed to quantify collagen fiber organization and undulation (n = 3/genotype). Increased pressure significantly increased creep strain in the wildtype, but not the haploinsufficient vagina. The axial length did not significantly affect the creep rate or strain in both genotypes. Collagen undulation varied through the depth of the subepithelium but not between genotypes. These findings suggest that the creep response to loading may vary with biological processes and pathologies, therefore, evaluating vaginal creep under various circumferential loads may be important to understand vaginal function.

Shear Wave Elastography to Assess Perineal Body Stiffness During Labor

OBJECTIVES

The objective of this study was to evaluate perineal body stiffness intrapartum using shear wave elastography ultrasound and to study its association with maternal and labor characteristics.

METHODS

This was a prospective observational study. Pregnant women with term pregnancy who had been admitted for labor management were recruited into the study. Transperineal shear wave elastography of perineal body was performed. Maternal and labor data were retrieved from electronic medical charts.

RESULTS

Thirty-two patients' data were available for analysis. Mean (SD) melastography modulus was 15.33 (5.49). While comparing the mean elastography modulus across maternal and labor characteristics, the difference was statistically different between parity, cervical dilation, and perineal laceration presence groups (P < 0.05). The mean of elastography modulus of primiparous women with cervical dilation less than 3 cm was 21.47 kPa, whereas that of multiparous women was 13.17 kPa (P = 0.0511). Perineal laceration was more prevalent in women with stiffer perineal body. The risk of having perineal laceration compared with no perineal laceration was 29.1% higher for each additional unit increase in perineal body elastography modulus (odds ratio, 0.709; 95% confidence interval, 0.507-0.992).

CONCLUSIONS

Shear wave elastography can be used to quantify perineal body stiffness. Primiparous women in early stages of labor have stiffer perineal body than multiparous women in any stage of labor and primiparous women in late stage of labor.

New insight into glycation levels and pelvic organ prolapse - A combination of clinical and biochemical studies

OBJECTIVES

Pelvic Organ Prolapse (POP) is a multifactorial disease with ageing as a most notable risk factor. Advanced Glycation End products (AGEs), biochemical markers of ageing are increased in prolapsed tissues. It is however unclear if AGEs are a cause or outcome of prolapse. By combining analysis of clinically relevant parameters in women with prolapse and POP tissues biochemically, this study aims to bridge the gap between existing clinical and biochemical research on the cause of POP.

METHODS

Following national and local ethical approval, a case study of 49 POP and 16 control tissues was carried out. The AGEs' marker, pentosidine, was quantified via High Performance Liquid Chromatography. Oestrogen (ER-α) and glyoxalase I (GLO-I) expression of the tissues were studied. Age, obstetric factors and co-morbidities (hypertension, smoking, diabetes mellitus) were recorded and compared with biochemical findings.

RESULTS

Lower expressions of ER-α and GLO-I were observed in POP tissues in the comparison to the control, which also had significantly higher pentosidine content. Prolapsed tissue population had more notable age-dependent increase in pentosidine with significant differences between the 6^th and 7^th decade. Hypertension and smoking, which were more prevalent amongst women with POP, were associated with higher amounts of pentosidine in the vaginal tissues.

CONCLUSION

In the light of recent research regarding the relationship between POP and glycation, the present study shows that age-related oestrogen decline is a key player in glycation accumulation in prolapsed vaginal tissues and that glycation is a cause rather than an effect of prolapse. Hypertension is a significant POP association which is linked to high glycation level.

Perspective of Advanced Glycation End Products on Human Health

In the last 20 years, the effects of advanced glycation end products (AGEs) on health have received increasing attention. High AGE levels in the body correlate with the progression of many diseases, such as diabetes, cardiovascular disease, and some cancers. However, whether AGEs are a cause of these diseases or represent accompanying symptoms of these diseases still needs to be elucidated by more comprehensive research. Recently, many researchers have begun to investigate the effects of AGE intake-induced variations of gut microbiota on disease progression, which will further explain the impact of AGEs on health and open a new chapter in AGE research.

Skin advanced glycation content reflects vaginal tissue glycation level in relation to pregnancy

A few studies have revealed that the advanced glycation content of the vaginal wall in pelvic organ prolapse tissues is elevated. This elevation makes advanced glycation a significant association with the disease. Early detection of vaginal wall glycation could therefore be relevant in the prevention and management of pelvic organ prolapse. A vaginal wall biopsy to detect this would be ideal, but is invasive. Therefore the use of a more accessible organ to access, such as skin, would be beneficial. Our previous independent study suggests that conditions such as pregnancy, can induce a change in the vaginal tissues' glycation content. The aim of this study was to assess whether the skin glycation undergoes similar changes as observed in vaginal tissue glycation in the same subjects in order to prove the hypothesis that skin advanced glycation content can predict vaginal tissue glycation. A rat model was used. The vaginal tissues from non-pregnant and E15-E18 pregnant rats and skin tissues from the same rats were taken for the measurement of advanced glycation content. The glycation marker, pentosidine, was quantified by a high performance liquid chromatography. Our results demonstrated that glycation content in vaginal wall tissues from pregnant rats was lower than the tissues from non-pregnant ones, and a strong positive association between skin and vaginal wall pentosidine level was observed. We conclude that skin pentosidine is reflective of vaginal wall pentosidine. Skin glycation may therefore be a potential tool in the prediction and management of pelvic organ prolapse.