The effect of metformin treatment on ovarian stromal blood flow in women with polycystic ovary syndrome

Variations in the Profiles of Vascular-Related Factors Among Different Sub-Types of Polycystic Ovarian Syndrome in Northern China

Recently, a growing body of evidence has suggested that abnormal ovarian angiogenesis, secondary to the imbalance between various angiogenic markers, is involved in the pathogenesis of PCOS, and this has led to the use of various interventions (such as Diane-35) to restore the normal ovarian angiogenesis. Therefore, we conducted the current investigation to determine the role of such markers (endothelial growth factor (VEGF), endostatin (ES), and thrombospondin-1 (TSP-1)) in the pathogenesis of PCOS along with the associated changes in ovarian blood flow in patients with PCOS compared to healthy controls, both before and after a course of oral contraception. A total of 381 patients with PCOS and 98 healthy females of childbearing age were recruited from July 2014 to June 2017 at the Reproductive Center of the Second Affiliated Hospital of Harbin Medical University. The serum levels of VEGF, ES, and TSP-1 were determined by enzyme-linked immunosorbent assay, while ovarian perfusion was measured by the pulsatility index (PI) and resistance index (RI) by using transvaginal color Doppler ultrasound. Repeated analyses were carried out after 3 months of Diane-35 treatment. Post-treatment serum levels of luteinizing hormone (LH)/follicle stimulating hormone (FSH) ratio of patients with PCOS decreased significantly (P <0.05). The RI values of most PCOS patients increased after treatment (P<0.05), while PI was significantly increased in all patients (P<0.05). However, variable changes in the serum levels of TSP-1, VEGF, and ES after treatment were observed. Serum VEGF levels showed a negative correlation with serum LH/FSH ratio, T concentration, and ES (P <0.05), while ES levels were negatively correlated with serum T concentrations only (P<0.05). The markers of angiogenesis (VEGF, ES, and TSP-1) were expressed differently among PCOS patients, who also responded differently to the same course of Diane-35 treatment. This field still warrants further investigation to reach a more definitive conclusion.

The effect of myoinositol on ovarian blood flows in women with polycystic ovary syndrome

To evaluate whether 4 gram myoinositol and 400 mcg folic acid(MYO) therapy has any effects on ovarian stromal blood flow by using pulsed and color Doppler at 3 months follow-up period in polycystic ovary syndrome (PCOS). One-hundred eighty patients were designed into six groups; Group 1: PCOS patients that received OCP containing 30 mcg ethinyl estradiol (EE) plus 3 mg drospirenone (DRP); Group 2: PCOS patients that received MYO; Group 3: PCOS patients that received no medication. Group 4: Healthy patients that received OCP; Group 5: Healthy patients that received MYO; Group 6: Healthy patients that received no medication. Resistance index (RI) and pulsatility index (PI) of both ovaries were assessed. There was a significant increase in RI and PI of both ovarian stromal blood flow women with PCOS who received OCP (Group 1, p < .001) and MYO (Group 2, p < .001). The rate of increment in both RI and PI values were similar for OCP users (Group 1) and MYO users(Group2) in PCOS patients. MYO therapy reduced ovarian vascularization in both PCOS and healthy users after 3 months and this decrease is especially noticeable in women with PCOS compared to healthy women. OCP therapy also reduced ovarian vascularization just like MYO therapy.

Uterine Artery Doppler in Pregnancy: Women with PCOS Compared to Healthy Controls

The objective of this study was to investigate possible differences in uterine artery pulsatility index (UtAPI) between pregnant women with PCOS and healthy controls and to explore possible effects of metformin on UtAPI. Material and Methods. The study was conducted in a tertiary center. Forty-eight pregnant women diagnosed with PCOS before pregnancy and 124 healthy pregnant women were included. Women with PCOS were randomly assigned to metformin 2000 mg daily or a placebo. UtAPI was measured five times during 1st and 2nd trimesters of pregnancy in women with PCOS and four times in healthy controls. Results. There was no difference in UtAPI between PCOS women and healthy controls at any point in time (p = 0.34-0.77). In women with PCOS, randomly assigned to metformin 2000 mg or placebo, UtAPI was unaffected by metformin two hours after intake of the first dose of study medication (p = 0.34). All PCOS women, regardless of randomization, had higher UtAPI two hours after intake of study medication and a meal compared to before a meal (p = 0.02). Conclusions. In the first and second trimesters of pregnancy, there was no difference in UtAPI between women with PCOS and healthy controls. Metformin had no immediate effect on the UtAPI. Interestingly, blood flow decreased after a meal, suggesting that time since last meal should be taken into consideration when interpreting the results of UtAPI measurements in pregnancy. This trial is registered with ClinicalTrials.gov (NCT00466622) Metformin in Pregnant PCOS women (PregMet) (NCT00159536).

The effect of drospirenone (3 mg) with ethinyl estradiol (30 mcg) containing pills on ovarian blood flows in women with polycystic ovary syndrome: a case controlled study

OBJECTIVE

To evaluate whether oral contraceptive pill (OCP) therapy has any effects on ovarian stromal blood flow by using pulsed and color Doppler at the end of 3 months follow-up period of OCP-users and non-users with or without polycystic ovary syndrome (PCOS).

STUDY DESIGN

200 patients were included in the study. The patients were designed into four groups as follows; Group 1: PCOS patients that received OCP containing 30 mcg ethinyl estradiol (EE) plus 3mg drospirenone for 3 months (DRP n=50); Group 2: PCOS patients that received no medication (n=50); Group 3: Healthy controls that received OCP (EE plus DRP) (n=50); Group 4: healthy controls that received no medication (n=50). Resistance index (RI) and pulsatility index (PI) of both ovarian arteries, hormonal, anthropometric and biochemical parameters were assessed before and after 3 months.

RESULTS

There was a significant increament in RI and PI of both ovarian arteries in healthy controls (Group 3) and in women with PCOS (Group 1) who received OCP (p<0.001). The increment rate in both Doppler parameters were significantly higher in women with PCOS (Group 1) than healthy controls (Group 3) (p<0.001). Whereas RI and PI values of both ovaries remained unchanged in all untreated women with or without PCOS (Groups 2 and 4).

CONCLUSION

OCP therapy reduced ovarian vascularization in both PCOS and healthy users after 3 months of therapy and this decrease is especially noticeable in women with PCOS.

Midpregnancy Doppler ultrasound of the uterine artery in metformin- versus placebo-treated PCOS women: a randomized trial

CONTEXT

Metformin is used to reduce pregnancy complications in women with polycystic ovary syndrome (PCOS), although it is not approved for this indication and solid evidence is lacking. Midpregnancy Doppler ultrasound is one of the best methods for prediction of adverse pregnancy outcome.

OBJECTIVE

The objectives of the study were to investigate the following: 1) whether metformin treatment influenced the midpregnancy pulsatility index (PI) of the uterine artery; 2) whether metabolic or endocrine factors affect the PI of the uterine artery of PCOS women; and 3) whether PI predicted adverse pregnancy outcome in PCOS woman.

DESIGN

This is a substudy of a randomized, placebo-controlled, double-blind, multicenter study conducted at 11 secondary care centers. We randomly assigned 273 pregnancies to receive metformin or placebo, from the first trimester of pregnancy to delivery. In the present substudy, 231 pregnancies are included, ie, those who completed the ultrasound examinations.

MAIN OUTCOME MEASURES

Midpregnancy PI in the uterine artery related to metformin use, androgen levels, an oral glucose tolerance test, and insulin levels was measured. We found no difference in the PI between the metformin and placebo groups. In multivariate analyses, fasting serum glucose of the first and second trimester correlated positively to the midpregnancy PI. Only in univariate analyses a weak correlation between androstenedione and PI was seen.

CONCLUSIONS

Metformin treatment did not affect uterine artery blood flow, measured by PI. High fasting blood glucose correlated inversely to uterine artery blood flow. The midpregnancy PI correlated positively to preeclampsia, hypertension, and gestational diabetes mellitus in PCOS pregnancies. Androgen levels correlated only to PI in univariate analyses.

Assessment of ovarian stromal blood flow after metformin treatment in women with polycystic ovary syndrome

PURPOSE

To authenticate the effect of metformin treatment on ovarian stromal blood flow in women with polycystic ovary syndrome (PCOS) using 3-dimensional (3D) power Doppler.

METHODS

The current case-control study was conducted at Ain Shams University Maternity Hospital. A total of 60 women diagnosed to have PCOS were included as group 1. Another 40 fertile women who were recruited from outpatient clinic for contraception without PCOS with regular menstrual cycles were included as control group (group 2). All women underwent 3D power Doppler evaluations of ovarian stroma. Anthropometric, hormonal and biochemical criteria were also measured. All women in group 1 received metformin hydrochloride 500 mg tablets, which were started in a step-up maneuver every 5 days, from one to three tablets per day. The same parameters were also measured after the 3 months duration of treatment.

RESULTS

A total of 100 women were finally analyzed. At the start of the study, there were no statistically significant differences between group 1 and group 2 and regarding age and body mass index, but the waist/hip ratio and Ferriman-Gallwey scoring were statistically different between the 2 groups. The mean ovarian volume and stromal volume were significantly larger in group 1. 3D power Doppler indices [the vascularization index (VI), the flow index (FI) and the (VFI) vascularization-flow index] were much higher in group 1 than in group 2 (1.38 ± 0.76 vs. 4.69 ± 1.37, P < 0.05, 26.59 ± 2.26 vs. 32.66 ± 4.37, P < 0.05, and 0.76 ± 0.39 vs. 1.54 ± 0.69, P < 0.05, respectively). After 3 months of using metformin in normal weight PCO women, there was a statistically significant improvement in group 1 regarding, hirsutism, most of hormonal measurements. Also 3 months metformin treatment significantly reduce VI, FI and VFI (4.69 ± 1.37 vs. 2.95 ± 1.52, P < 0.05, 32.66 ± 4.37 vs. 29.48 ± 4.98, P < 0.05 and 1.54 ± 0.69 vs. 1.21 ± 0.7 P < 0.05, respectively). Using Receiver operator characteristic, there was no cut-off value of VI, FI or VFI to detect ovulation in women of PCOS.

CONCLUSIONS

Metformin seems to have a beneficial effect in normal weight PCO women via correcting ovarian stromal blood flow and hormonal profiles.

Insulin-sensitizing agents in the treatment of polycystic ovary syndrome: an update

PURPOSE OF REVIEW

Polycystic ovary syndrome (PCOS) is the most frequent endocrinopathy in reproductive-aged women, mainly characterized by oligoanovulation and hyperandrogenism. Insulin resistance represents a major pathophysiological feature of the syndrome and, therefore, insulin-sensitizing agents (metformin and thiazolidinediones) have been applied in PCOS women. However, the clinical use of insulin sensitizers in PCOS has been debated. The aim of the current review was to update the knowledge regarding the role of metformin and thiazolidinediones in PCOS treatment, focusing on recently published studies.

RECENT FINDINGS

Several clinical trials examined metformin effectiveness on lipids, atherosclerosis and inflammatory markers, hormone levels, menstrual irregularities, ovulation induction, fertility, hirsutism, obesity parameters and quality of life in PCOS women. Metformin treatment was shown to improve these features, although conflicting results were also reported. Only one study investigated pioglitazone effect on PCOS, reporting an improved IVF outcome in clomiphene citrate-resistant PCOS patients. Finally, both metformin and pioglitazone, as a part of a low-dose polytherapy, exerted beneficial effects on lipids, androgen levels, hirsutism and markers of atherosclerosis in nonobese PCOS women.

SUMMARY

Further research, including larger randomized controlled trials and meta-analyses, is needed to clarify the role of metformin and thiazolidinediones in the treatment of clinical and biochemical PCOS characteristics.

Prenatal androgenization of female mice programs an increase in firing activity of gonadotropin-releasing hormone (GnRH) neurons that is reversed by metformin treatment in adulthood

Prenatal androgenization (PNA) of female mice with dihydrotestosterone programs reproductive dysfunction in adulthood, characterized by elevated luteinizing hormone levels, irregular estrous cycles, and central abnormalities. Here, we evaluated activity of GnRH neurons from PNA mice and the effects of in vivo treatment with metformin, an activator of AMP-activated protein kinase (AMPK) that is commonly used to treat the fertility disorder polycystic ovary syndrome. Estrous cycles were monitored in PNA and control mice before and after metformin administration. Before metformin, cycles were longer in PNA mice and percent time in estrus lower; metformin normalized cycles in PNA mice. Extracellular recordings were used to monitor GnRH neuron firing activity in brain slices from diestrous mice. Firing rate was higher and quiescence lower in GnRH neurons from PNA mice, demonstrating increased GnRH neuron activity. Metformin treatment of PNA mice restored firing activity and LH to control levels. To assess whether AMPK activation contributed to the metformin-induced reduction in GnRH neuron activity, the AMPK antagonist compound C was acutely applied to cells. Compound C stimulated cells from metformin-treated, but not untreated, mice, suggesting that AMPK was activated in GnRH neurons, or afferent neurons, in the former group. GnRH neurons from metformin-treated mice also showed a reduced inhibitory response to low glucose. These studies indicate that PNA causes enhanced firing activity of GnRH neurons and elevated LH that are reversible by metformin, raising the possibility that central AMPK activation by metformin may play a role in its restoration of reproductive cycles in polycystic ovary syndrome.