Endothelial dysfunction in subfertile women with polycystic ovary syndrome

RESEARCH QUESTION

Is there an association between post-occlusive reactive hyperaemia (PORH) and ovarian stimulation in women with normoandrogenaemic polycystic ovary syndrome (PCOS)?

DESIGN

Women eligible for IVF at an academic fertility centre were invited to join this prospective study. Microvascular endothelial function was measured as PORH by laser Doppler flowmetry (LDF) before and after ovarian stimulation. Metabolic characteristics, hormone profiles and biochemical markers were analysed.

RESULTS

Thirty-four normoandrogenaemic women with PCOS and 36 normoandrogenaemic women without PCOS were included. The PCOS group displayed higher C-reactive protein levels and insulin resistance (P = 0.048 and P = 0.025, respectively). No significant difference was found in microcirculatory function between the groups at baseline. After ovarian stimulation, PORH was enhanced in the control group (slope 7.1 ± 3.3 versus 9.7 ± 4.5; P = 0.007; peak flow 30.7 ± 16.3 versus 43.5 ± 17.3, P = 0.008; however, the PCOS group experienced a blunting response to supraphysiological hormone status (slope 8.2 ± 5.1 versus 7.2 ± 4.3, P = 0.212; peak flow, 38.8 ± 19.4 versus 37.0 ± 21.8, P = 0.895).

CONCLUSIONS

Impaired microcirculatory function could be found using a non-invasive LDF technique in normoandrogenaemic women with PCOS undergoing IVF, indicating early changes in vascular endothelial dysfunction. Future observational studies should clarify whether PORH measurement might help predict IVF prognosis or obstetric complications.

Beat-to-beat and spectral analyses of the noninvasive radial pulse and laser-Doppler signals in patients with hypertension

This study performed beat-to-beat and spectral analyses of 20-minute skin-surface laser-Doppler-flowmetry (LDF) and radial blood-pressure-waveform (BPW) signals in order to compare the blood-flow perfusion condition and regulatory mechanisms between essential-hypertension (EHT) patients and aged-matched control subjects. Beat-to-beat LDF analyses yielded the pulse width (PW), AC-to-DC ratio (AD), and their corresponding variability indices (coefficients of variation [CVs]). The relative energy contributions (RECs) of five characteristic frequency peaks (defined as FR1-FR5) were also calculated. Spectral BPW analysis obtained the amplitude proportion (Cn) and phase angle (Pn) of each harmonic component n. PW, AD, AD_CV, and REC of FR2 were significantly smaller in the EHT group than in the control group. Regarding BPW indices, C1, C2, C4, and C5 were significantly larger and P2-P8 were significantly smaller in EHT patients than in controls. The present results indicate that BPW and LDF indices can be used to evaluate the blood-flow perfusion efficiency and microcirculatory regulatory activities in EHT. Sex differences were found, with the effects being more prominent in female patients. These findings may be partly attributable to impairment of endothelial and neural regulatory functions. The present findings might aid the development of new noninvasive methods for reducing the risk of EHT-induced damage.

Fundamental supply of skin blood flow in the Chinese Han population: Measurements by a full-field laser perfusion imager

BACKGROUND

Skin blood flow is believed to link with many diseases, and shows a significant heterogeneity. There are several papers on basal cutaneous microcirculation perfusion in different races, while the data in Chinese is vacant.

OBJECTIVE

The aim was to establish the database of absolute fundamental supply of skin blood flow in the Chinese Han population.

METHODS

With a full-field laser perfusion imager (FLPI), the skin blood flow can be quantified. Cutaneous perfusion values were determined in 17 selected skin areas in 406 healthy participants aged between 20 and 80 years (mean 35.05 ± 11.33). Essential parameters such as weight, height were also measured and values of BMI were calculated. The perfusion values were reported in Arbitrary Perfusion Units (APU).

RESULTS

The highest cutaneous perfusion value fell on eyelid (931.20 ± 242.59 in male and 967.83 ± 225.49 in female), and pretibial had the lowest value (89.09 ± 30.28 in male and 85.08 ± 33.59 in female). The values were higher in men than women on the bank of fingertips, nose, forehead, cheek, neck and earlobe (P < .05). Perfusion values on stretch and flexion side of forearm had negative correlation with age (P = .01 and P = 4.88 × 10^-3 , respectively) in male. Abdomen was negatively correlated with BMI in both gender (P = .02, respectively).

CONCLUSIONS

Skin blood flow values vary with skin regions. There is a tendency to measure higher perfusion values in men than in women. And the values are irrelevant with age or BMI.

Shape analysis of the microcirculatory flow wave

The cardiovascular system and its alterations are a crucial aspect of physiology and medicine. Non-invasive assessment of the functional properties of circulation is of considerable interest to clinicians and physiologists. In this work we investigate the possibility of detecting alterations of the flow waveform in microcirculation, using non-invasive measurements based on a laser Doppler flowmeter. As a test case, we focus on the effect of ageing. Skin is warmed up to a fixed temperature (44 °C) during measurement, to increase blood flow. The shape of the perfusion waveform during each heart beat after the flow was stabilized was used to estimate dynamic parameters of the microcirculatory system. Both the wave rise time, defined as the delay between the diastolic minimum and the following systolic maximum, and the oscillation fraction, defined as the normalized difference between the maximum and minimum flow, present significant variation with age.