Global Practice Patterns and Variations in the Medical and Surgical Management of Non-Obstructive Azoospermia: Results of a World-Wide Survey, Guidelines and Expert Recommendations

PURPOSE

Non-obstructive azoospermia (NOA) is a common, but complex problem, with multiple therapeutic options and a lack of clear guidelines. Hence, there is considerable controversy and marked variation in the management of NOA. This survey evaluates contemporary global practices related to medical and surgical management for patients with NOA.

MATERIALS AND METHODS

A 56-question online survey covering various aspects of the evaluation and management of NOA was sent to specialists around the globe. This paper analyzes the results of the second half of the survey dealing with the management of NOA. Results have been compared to current guidelines, and expert recommendations have been provided using a Delphi process.

RESULTS

Participants from 49 countries submitted 336 valid responses. Hormonal therapy for 3 to 6 months was suggested before surgical sperm retrieval (SSR) by 29.6% and 23.6% of participants for normogonadotropic hypogonadism and hypergonadotropic hypogonadism respectively. The SSR rate was reported as 50.0% by 26.0% to 50.0% of participants. Interestingly, 46.0% reported successful SSR in <10% of men with Klinefelter syndrome and 41.3% routinely recommended preimplantation genetic testing. Varicocele repair prior to SSR is recommended by 57.7%. Half of the respondents (57.4%) reported using ultrasound to identify the most vascularized areas in the testis for SSR. One-third proceed directly to microdissection testicular sperm extraction (mTESE) in every case of NOA while others use a staged approach. After a failed conventional TESE, 23.8% wait for 3 months, while 33.1% wait for 6 months before proceeding to mTESE. The cut-off of follicle-stimulating hormone for positive SSR was reported to be 12-19 IU/mL by 22.5% of participants and 20-40 IU/mL by 27.8%, while 31.8% reported no upper limit.

CONCLUSIONS

This is the largest survey to date on the real-world medical and surgical management of NOA by reproductive experts. It demonstrates a diverse practice pattern and highlights the need for evidence-based international consensus guidelines.

Global Practice Patterns in the Evaluation of Non-Obstructive Azoospermia: Results of a World-Wide Survey and Expert Recommendations

PURPOSE

Non-obstructive azoospermia (NOA) represents the persistent absence of sperm in ejaculate without obstruction, stemming from diverse disease processes. This survey explores global practices in NOA diagnosis, comparing them with guidelines and offering expert recommendations.

MATERIALS AND METHODS

A 56-item questionnaire survey on NOA diagnosis and management was conducted globally from July to September 2022. This paper focuses on part 1, evaluating NOA diagnosis. Data from 367 participants across 49 countries were analyzed descriptively, with a Delphi process used for expert recommendations.

RESULTS

Of 336 eligible responses, most participants were experienced attending physicians (70.93%). To diagnose azoospermia definitively, 81.7% requested two semen samples. Commonly ordered hormone tests included serum follicle-stimulating hormone (FSH) (97.0%), total testosterone (92.9%), and luteinizing hormone (86.9%). Genetic testing was requested by 66.6%, with karyotype analysis (86.2%) and Y chromosome microdeletions (88.3%) prevalent. Diagnostic testicular biopsy, distinguishing obstructive azoospermia (OA) from NOA, was not performed by 45.1%, while 34.6% did it selectively. Differentiation relied on physical examination (76.1%), serum hormone profiles (69.6%), and semen tests (68.1%). Expectations of finding sperm surgically were higher in men with normal FSH, larger testes, and a history of sperm in ejaculate.

CONCLUSIONS

This expert survey, encompassing 367 participants from 49 countries, unveils congruence with recommended guidelines in NOA diagnosis. However, noteworthy disparities in practices suggest a need for evidence-based, international consensus guidelines to standardize NOA evaluation, addressing existing gaps in professional recommendations.

Evaluating the satisfaction and utility of social networks in medical practice and continuing medical education

BACKGROUND

Digital health has surged during the Covid health crisis, and the use of social media, already prevalent in medicine, has significantly increased. There are Social Networks groups dedicated to physicians with an educational purpose. These groups also facilitate peer discussions on medical questions and the sharing of training materials.

OBJECTIVES

The aim of our study was to assess the value of these new tools and their contribution to medical education.

METHODS

An anonymous questionnaire was conducted among members of a Social Networks community group for physicians. The survey received responses from 1451 participants.

RESULTS

The majority of participants believed they had enriched their medical knowledge and accessed documents they would not have accessed without the group. Subgroup analysis showed that the contribution of this tool is more pronounced for general practitioners and doctors practicing in limited healthcare access.

CONCLUSION

It is essential to develop digital tools that enhance physician training, and social networks represent a valuable educational tool.

Does Varicocele Repair Improve Conventional Semen Parameters? A Meta-Analytic Study of Before-After Data

PURPOSE

The purpose of this meta-analysis is to study the impact of varicocele repair in the largest cohort of infertile males with clinical varicocele by including all available studies, with no language restrictions, comparing intra-person conventional semen parameters before and after the repair of varicoceles.

MATERIALS AND METHODS

The meta-analysis was performed according to PRISMA-P and MOOSE guidelines. A systematic search was performed in Scopus, PubMed, Cochrane, and Embase databases. Eligible studies were selected according to the PICOS model (Population: infertile male patients with clinical varicocele; Intervention: varicocele repair; Comparison: intra-person before-after varicocele repair; Outcome: conventional semen parameters; Study type: randomized controlled trials [RCTs], observational and case-control studies).

RESULTS

Out of 1,632 screened abstracts, 351 articles (23 RCTs, 292 observational, and 36 case-control studies) were included in the quantitative analysis. The before-and-after analysis showed significant improvements in all semen parameters after varicocele repair (except sperm vitality); semen volume: standardized mean difference (SMD) 0.203, 95% CI: 0.129-0.278; p<0.001; I²=83.62%, Egger's p=0.3329; sperm concentration: SMD 1.590, 95% CI: 1.474-1.706; p<0.001; I²=97.86%, Egger's p<0.0001; total sperm count: SMD 1.824, 95% CI: 1.526-2.121; p<0.001; I²=97.88%, Egger's p=0.0063; total motile sperm count: SMD 1.643, 95% CI: 1.318-1.968; p<0.001; I²=98.65%, Egger's p=0.0003; progressive sperm motility: SMD 1.845, 95% CI: 1.537%-2.153%; p<0.001; I²=98.97%, Egger's p<0.0001; total sperm motility: SMD 1.613, 95% CI 1.467%-1.759%; p<0.001; l2=97.98%, Egger's p<0.001; sperm morphology: SMD 1.066, 95% CI 0.992%-1.211%; p<0.001; I²=97.87%, Egger's p=0.1864.

CONCLUSIONS

The current meta-analysis is the largest to date using paired analysis on varicocele patients. In the current meta-analysis, almost all conventional semen parameters improved significantly following varicocele repair in infertile patients with clinical varicocele.

Controversy and Consensus on the Management of Elevated Sperm DNA Fragmentation in Male Infertility: A Global Survey, Current Guidelines, and Expert Recommendations

PURPOSE

Sperm DNA fragmentation (SDF) has been associated with male infertility and poor outcomes of assisted reproductive technology (ART). The purpose of this study was to investigate global practices related to the management of elevated SDF in infertile men, summarize the relevant professional society recommendations, and provide expert recommendations for managing this condition.

MATERIALS AND METHODS

An online global survey on clinical practices related to SDF was disseminated to reproductive clinicians, according to the CHERRIES checklist criteria. Management protocols for various conditions associated with SDF were captured and compared to the relevant recommendations in professional society guidelines and the appropriate available evidence. Expert recommendations and consensus on the management of infertile men with elevated SDF were then formulated and adapted using the Delphi method.

RESULTS

A total of 436 experts from 55 different countries submitted responses. As an initial approach, 79.1% of reproductive experts recommend lifestyle modifications for infertile men with elevated SDF, and 76.9% prescribe empiric antioxidants. Regarding antioxidant duration, 39.3% recommend 4-6 months and 38.1% recommend 3 months. For men with unexplained or idiopathic infertility, and couples experiencing recurrent miscarriages associated with elevated SDF, most respondents refer to ART 6 months after failure of conservative and empiric medical management. Infertile men with clinical varicocele, normal conventional semen parameters, and elevated SDF are offered varicocele repair immediately after diagnosis by 31.4%, and after failure of antioxidants and conservative measures by 40.9%. Sperm selection techniques and testicular sperm extraction are also management options for couples undergoing ART. For most questions, heterogenous practices were demonstrated.

CONCLUSIONS

This paper presents the results of a large global survey on the management of infertile men with elevated SDF and reveals a lack of consensus among clinicians. Furthermore, it demonstrates the scarcity of professional society guidelines in this regard and attempts to highlight the relevant evidence. Expert recommendations are proposed to help guide clinicians.

Impact of Varicocele Repair on Semen Parameters in Infertile Men: A Systematic Review and Meta-Analysis

PURPOSE

Despite the significant role of varicocele in the pathogenesis of male infertility, the impact of varicocele repair (VR) on conventional semen parameters remains controversial. Only a few systematic reviews and meta-analyses (SRMAs) have evaluated the impact of VR on sperm concentration, total motility, and progressive motility, mostly using a before-after analytic approach. No SRMA to date has evaluated the change in conventional semen parameters after VR compared to untreated controls. This study aimed to evaluate the effect of VR on conventional semen parameters in infertile patients with clinical varicocele compared to untreated controls.

MATERIALS AND METHODS

A literature search was performed using Scopus, PubMed, Embase, and Cochrane databases following the Population Intervention Comparison Outcome (PICOS) model (Population: infertile patients with clinical varicocele; Intervention: VR [any technique]; Comparison: infertile patients with clinical varicocele that were untreated; Outcome: sperm concentration, sperm total count, progressive sperm motility, total sperm motility, sperm morphology, and semen volume; Study type: randomized controlled trials and observational studies).

RESULTS

A total of 1,632 abstracts were initially assessed for eligibility. Sixteen studies were finally included with a total of 2,420 infertile men with clinical varicocele (1,424 patients treated with VR vs. 996 untreated controls). The analysis showed significantly improved post-operative semen parameters in patients compared to controls with regards to sperm concentration (standardized mean difference [SMD] 1.739; 95% CI 1.129 to 2.349; p<0.001; I²=97.6%), total sperm count (SMD 1.894; 95% CI 0.566 to 3.222; p<0.05; I²=97.8%), progressive sperm motility (SMD 3.301; 95% CI 2.164 to 4.437; p<0.01; I²=98.5%), total sperm motility (SMD 0.887; 95% CI 0.036 to 1.738; p=0.04; I²=97.3%) and normal sperm morphology (SMD 1.673; 95% CI 0.876 to 2.470; p<0.05; I²=98.5%). All the outcomes showed a high inter-study heterogeneity, but the sensitivity analysis showed that no study was sensitive enough to change these results. Publication bias was present only in the analysis of the sperm concentration and progressive motility. No significant difference was found for the semen volume (SMD 0.313; 95% CI -0.242 to 0.868; I²=89.7%).

CONCLUSIONS

This study provides a high level of evidence in favor of a positive effect of VR to improve conventional semen parameters in infertile men with clinical varicocele. To the best of our knowledge, this is the first SRMA to compare changes in conventional semen parameters after VR with changes in parameters of a control group over the same period. This is in contrast to other SRMAs which have compared semen parameters before and after VR, without reference to a control group. Our findings strengthen the available evidence and have a potential to upgrade professional societies' practice recommendations favoring VR to improve conventional semen parameters in infertile men.

Ovarian tissue cryopreservation can be combined simultaneously with oocyte retrieval after controlled ovarian hyperstimulation

STUDY QUESTION

Can ovarian tissue cryopreservation (OTC) be performed after controlled ovarian hyperstimulation (COH)?

SUMMARY ANSWER

Unilateral oophorectomy after transvaginal oocyte retrieval is feasible on stimulated ovaries during one surgical step.

WHAT IS KNOWN ALREADY

In the fertility preservation (FP) field, the timeframe between patient referral and start of curative treatment is limited. Combining oocyte pick-up with ovarian tissue (OT) extraction has been reported to improve FP but COH applied before OT extraction is not currently recommended.

STUDY DESIGN, SIZE, DURATION

This retrospective cohort-controlled study involved 58 patients who underwent oocyte cryopreservation immediately followed by OTC between September 2009 and November 2021. The exclusion criteria were a delay between oocyte retrieval and OTC of >24 h (n = 5) and IVM of oocytes obtained ex vivo in the ovarian cortex (n = 2). This FP strategy was performed either after COH (stimulated group, n = 18) or after IVM (unstimulated group, n = 33).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Oocyte retrieval followed by OT extraction on the same day was performed either without previous stimulation or after COH. Adverse effects of surgery and ovarian stimulation, mature oocyte yield and pathology findings of fresh OT were retrospectively analysed. Thawed OTs were analysed prospectively, for vascularization and apoptosis using immunohistochemistry, when patient consent was obtained.

MAIN RESULTS AND THE ROLE OF CHANCE

No surgical complication occurred after OTC surgery in either group. In particular, no severe bleeding was associated with COH. The number of mature oocytes obtained increased after COH (median = 8.5 (25% = 5.3-75% = 12.0)) compared to the unstimulated group (2.0 (1.0-5.3), P < 0.001). Neither ovarian follicle density nor cell integrity was affected by COH. Fresh OT analysis showed congestion in half of the stimulated OT which was higher than in the unstimulated OT (3.1%, P < 0.001). COH also increased haemorrhagic suffusion (COH + OTC: 66.7%; IVM + OTC: 18.8%, P = 0.002) and oedema (COH + OTC: 55.6%; IVM + OTC: 9.4%, P < 0.001). After thawing, the pathological findings were similar between both groups. No statistical difference in the number of blood vessels was observed between the groups. The oocyte apoptotic rate in thawed OT was not statistically different between the groups (ratio of positive cleaved caspase-3 staining oocytes/total number of oocytes equal to median 0.50 (0.33-0.85) and 0.45 (0.23-0.58) in unstimulated and stimulated groups respectively, P = 0.720).

LIMITATIONS, REASONS FOR CAUTION

The study reports FP from a small number of women following OTC. Follicle density and other pathology findings are an estimate only.

WIDER IMPLICATIONS OF THE FINDINGS

Unilateral oophorectomy can be successfully performed after COH with limited bleeding risk and an absence of impact on thawed OT. This approach could be proposed to post pubertal patients when the number of mature oocytes expected is low or when the risk of residual pathology is high. The reduction of surgical steps for cancer patients also has positive implications for introducing this approach into clinical practice.

STUDY FUNDING/COMPETING INTEREST(S)

This work was made possible through the support of the reproductive department of Antoine-Béclère Hospital and of the pathological department of Bicêtre Hospital (Assistance Publique Hôpitaux de Paris, France). The authors have no conflict of interest to disclose in this study.

TRIAL REGISTRATION NUMBER

N/A.

Consensus and Diversity in the Management of Varicocele for Male Infertility: Results of a Global Practice Survey and Comparison with Guidelines and Recommendations

PURPOSE

Varicocele is a common problem among infertile men. Varicocele repair (VR) is frequently performed to improve semen parameters and the chances of pregnancy. However, there is a lack of consensus about the diagnosis, indications for VR and its outcomes. The aim of this study was to explore global practice patterns on the management of varicocele in the context of male infertility.

MATERIALS AND METHODS

Sixty practicing urologists/andrologists from 23 countries contributed 382 multiple-choice-questions pertaining to varicocele management. These were condensed into an online questionnaire that was forwarded to clinicians involved in male infertility management through direct invitation. The results were analyzed for disagreement and agreement in practice patterns and, compared with the latest guidelines of international professional societies (American Urological Association [AUA], American Society for Reproductive Medicine [ASRM], and European Association of Urology [EAU]), and with evidence emerging from recent systematic reviews and meta-analyses. Additionally, an expert opinion on each topic was provided based on the consensus of 16 experts in the field.

RESULTS

The questionnaire was answered by 574 clinicians from 59 countries. The majority of respondents were urologists/uro-andrologists. A wide diversity of opinion was seen in every aspect of varicocele diagnosis, indications for repair, choice of technique, management of sub-clinical varicocele and the role of VR in azoospermia. A significant proportion of the responses were at odds with the recommendations of AUA, ASRM, and EAU. A large number of clinical situations were identified where no guidelines are available.

CONCLUSIONS

This study is the largest global survey performed to date on the clinical management of varicocele for male infertility. It demonstrates: 1) a wide disagreement in the approach to varicocele management, 2) large gaps in the clinical practice guidelines from professional societies, and 3) the need for further studies on several aspects of varicocele management in infertile men.

Polypharmacy in older adults after transcatheter or surgical aortic valve replacement

Background

Polypharmacy is associated with higher rates of adverse drug events and unplanned hospital visits in medical patients. Little is known about polypharmacy in frail older adults undergoing transcatheter (TAVR) or surgical (SAVR) aortic valve replacement.

Purpose

To determine the prevalence and prognostic implications of polypharmacy and potentially inappropriate medications (PIM) following TAVR or SAVR.

Methods

A post hoc analysis of the McGill Frailty Registry was conducted. Patients 70 years of age or older who were discharged alive after TAVR or SAVR at two university hospitals were included. Discharge prescriptions were codified and analyzed using the MedSafer electronic tool that has been validated to flag drug interactions and PIMs considering patient-specific comorbidities. Associations with the primary outcome of 30-day all-cause readmission were examined by logistic regression after adjusting for age, sex, Charlson Comorbidity Index, and procedure type.

Results

The cohort consisted of 495 patients (52% TAVR, 21% isolated SAVR, 27% combined SAVR). The mean age was 80.1±5.5 years with 52% females. The mean number of medications was 10.2±3.7 with 90% having 5 or more medications. A total of 55 patients were readmitted within 30 days. While the total number of medications was not predictive, three specific PIMs were found to be harmful and one PIM was found to be protective for readmission: clopidogrel with warfarin or heparin (OR 3.99; 95% CI 1.47, 10.82), diltiazem with heart failure (OR 3.16; 95% CI 1.04, 36.41), doxazosin or terazosin with hypertension (OR 6.21; 95% CI 0.99, 38.88), and any proton pump inhibitor (OR 0.47; 95% CI 0.26, 0.86). Of note, the combination of clopidogrel with direct oral anticoagulants was not found to be harmful for readmission.

Conclusion

The prevalence of polypharmacy is elevated in older patients undergoing TAVR or SAVR. Specific PIMs, but not total number of medications prescribed, were found to be associated with potentially preventable readmissions.

Funding Acknowledgement

Type of funding sources: None.

Blanchard N, Fathallah K, Bendayan M, Benchaib M. P–127 Does sperm quality really matter for conceiving through an intrauterine insemination program? A retrospective analysis of 5920 attempts taking into account repetition of cycles

Study question

Are parameters of sperm quality part of the prognosis factors for an infertile couple to obtain a live birth when entering an intrauterine insemination program considering repetition of attempts?

Summary answer

Paradoxically, a lower sperm morphology independently predict quick live birth through IUI, as well as younger female age, lower D3 FSH, and higher triggering estradiol.

What is known already

Many studies have highlighted different prognosis factors for obtaining a live birth after IUI involving: male parameters (semen),female parameters (age, parity, ovulation, tubal, and endometriosis status, history of pelvic surgery),couple parameters (duration of infertility, number of previous attempt),IUI parameters (follicle number, endometrial thickness, estradiol at triggering, day of IUI, number of spermatozoa inseminated). However, most of these studies have included small number of attempts, semen parameters were either not collected or assessed with heterogeneity, and repetition of attempts (although iconic for IUI) was not considered, allocating inappropriate weight to cycles which failed in conceiving.

Study design, size, duration

We retrospectively studied the entire cohort of IUI attempts carried out with partner’s sperm at our center between 09/09/2003 and 01/17/2017. We included all male, female, couple and IUI parameters available. Each basic semen analyzes included have been carried out by a restricted number of skilled andrologists from our center. The closest semen assessment performed before IUI was considered as male parameter. IUI attempts were considered repeated unless a live birth or IUI abandonment occurred.

Participants/materials, setting, methods

Our primary outcome was live birth occurrence. We included 2228 couples having performed 5920 IUI attempts, with 636 live births obtained. A mixed logistic regression model was used to take into account IUI repetition before obtaining a live birth. A survival analysis using Cox model, with IUI rank as time variable, live birth as endpoint, and taking into account recurrences was carried out to determine which parameter best predict a quick live birth through IUI.

Main results and the role of chance

Included women were 33.7 ± 4.6 years old in mean. Baseline semen assessment was available for 64% of couples.

Muti-variate analysis showed that live birth was more frequent when: Femal factors: age was young (33 to 38yo, OR 0.76 [0.60;0.96], &gt;38 yo OR 0.49 [0.35;0.67], p = 0.0001), FSH ≤ 8.0 (OR 0.59 [0.45;0.79], p = 0.0002), AMH &gt; 8.9ng/mL (OR 0.59 [0.45;0.79], p = 0.0001), endometriosis was absent (OR 0.56 [0.36;0.88], p = 0.0109), the patient already delivered (OR 1.36 [1.06;1.74], p = 0.0034) Male factors: sperm motility ≤26.0% (OR 0.71 [0.53;0.96], p = 0.0062), sperm vitality ≤72.0% (OR 0.65 [0.47;0.90], p = 0.0032), sperm typical form ≤ 25.0% (OR 0.51 [0.34 ; 0.78], p = 0.0016), IUI attempt factors: total dose of gonadotropin &gt; 495.0 (OR 1.54 [1.26;1.88], p = 0.0001) follicle number &gt; 2 (OR 1.23 [1.69;2.21], p = 0.0296), Estradiol at trigerring &gt; 215.0pg/ml (OR 1.90 [1.53;2.36], p = 0.0001), Endometrial thickness &gt;9.6mm (OR 1.43, p = 0.0024), day of IUI &gt;13 (1.53 [1.24;1.89], p = 0.0001). Using Cox model, couples obtained quickly a livebirth if: woman age was below 33yo: For 33 to 38 yo, OR 0.37 [0.25;0.54], p = 0.0001, &gt;38yo OR 0.19 [0.11;0.32], p = 0.0001 D3 FSH&lt;8 (if above, OR 0.55 [0.34;0.90], p = 0.0160) - Sperm typical form ≤25.0 (if above, OR 0.34 [0.20;0.58], p = 0.0001) Triggering estradiol &gt;215.0pg/ml, OR 1.99 [1.51;2.63], p = 0.0001)

Limitations, reasons for caution

Baseline semen assessment was missing a bit more when cycles were successful, so that a bias connot be excluded. This weird result concerning semen parameters which appear to lower the live birth rate when they are good should thus be considered with caution.

Wider implications of the findings: Good baseline semen parameters do not appear as primordial for obtaining an IUI live birth, and were even found deleterious. However, thresholds highlighted in the present study were high, i.e. of limited clinical mean, and semen below them to remain normal. After confirming, explanations should be investigated: excessive acrosome reaction.

Trial registration number

Not applicable

[Environment and lifestyle: Impacts on male fertility?]

In this last century, an increase of men infertility has been registered. It has been suggested that environmental factors could a negative impact over sperm quality. Among these factors, impact of environmental toxicant has been spread by media. In this review of scientific literature, we identify several environmental factors that could impact men fertility in a negative way. These factors are tobacco, marijuana, weight, body mass index, heat, nutritional state, electromagnetic waves and altitude. For each of these factors, the impact over men fertility, their mechanism, as well their influence over the use of Assisted Reproductive Technics are reported.

Essential role of clusterin in pancreas regeneration

Based on our previous observations that clusterin induction accompanies pancreas regeneration in the rat, we sought to determine if regeneration might be impaired in mice that lacked clusterin. We studied the impact of absent clusterin on morphogenic and functional features of regenerating pancreas. Clusterin induction was accompanied in the regenerating pancreas by a robust development of new lobules with ductules, acini, and endocrine islets in wild type after partial pancreatectomy. In clusterin knock-out mice, however, pancreatectomy resulted in a poor formation of regenerating lobule. In particular, regeneration of beta-cells was also significantly reduced and was associated with persistent hyperglycemia. Duct cells obtained from pancreatectomized clusterin knock-out mice exhibited impaired beta-cell formation in vitro; this was restored by administration of exogenous clusterin. We suggest that clusterin plays a critical role to promote both exocrine and endocrine regeneration following pancreas injury, as well as for in vitro beta-cell regeneration.

Caspase-3-dependent export of TCTP: a novel pathway for antiapoptotic intercellular communication

The apoptotic program incorporates a paracrine component of importance in fostering tissue repair at sites of apoptotic cell deletion. As this paracrine pathway likely bears special importance in maladaptive intercellular communication leading to vascular remodeling, we aimed at further defining the mediators produced by apoptotic endothelial cells (EC), using comparative and functional proteomics. Apoptotic EC were found to release nanovesicles displaying ultrastructural characteristics, protein markers and functional activity that differed from apoptotic blebs. Tumor susceptibility gene 101 and translationally controlled tumor protein (TCTP) were identified in nanovesicle fractions purified from medium conditioned by apoptotic EC and absent from purified apoptotic blebs. Immunogold labeling identified TCTP on the surface of nanovesicles purified from medium conditioned by apoptotic EC and within multivesicular blebs in apoptotic EC. These nanovesicles induced an extracellular signal-regulated kinases 1/2 (ERK 1/2)-dependent antiapoptotic phenotype in vascular smooth muscle cells (VSMC), whereas apoptotic blebs did not display antiapoptotic activity on VSMC. Caspase-3 biochemical inhibition and caspase-3 RNA interference in EC submitted to a proapoptotic stimulus inhibited the release of nanovesicles. Also, TCTP siRNAs in EC attenuated the antiapoptotic activity of purified nanovesicles on VSMC. Collectively, these results identify TCTP-bearing nanovesicles as a novel component of the paracrine apoptotic program of potential importance in vascular repair.

Modulation of intestinal cholesterol absorption by high glucose levels: impact on cholesterol transporters, regulatory enzymes, and transcription factors

Growing evidence suggests that the small intestine may contribute to excessive postprandial lipemia, which is highly prevalent in insulin-resistant/Type 2 diabetic individuals and substantially increases the risk of cardiovascular disease. The aim of the present study was to determine the role of high glucose levels on intestinal cholesterol absorption, cholesterol transporter expression, enzymes controlling cholesterol homeostasis, and the status of transcription factors. To this end, we employed highly differentiated and polarized cells (20 days of culture), plated on permeable polycarbonate filters. In the presence of [(14)C]cholesterol, glucose at 25 mM stimulated cholesterol uptake compared with Caco-2/15 cells supplemented with 5 mM glucose (P < 0.04). Because combination of 5 mM glucose with 20 mM of the structurally related mannitol or sorbitol did not change cholesterol uptake, we conclude that extracellular glucose concentration is uniquely involved in the regulation of intestinal cholesterol transport. The high concentration of glucose enhanced the protein expression of the critical cholesterol transporter NPC1L1 and that of CD36 (P < 0.02) and concomitantly decreased SR-BI protein mass (P < 0.02). No significant changes were observed in the protein expression of ABCA1 and ABCG8, which act as efflux pumps favoring cholesterol export out of absorptive cells. At the same time, 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity was decreased (P < 0.007), whereas ACAT activity remained unchanged. Finally, increases were noted in the transcription factors LXR-alpha, LXR-beta, PPAR-beta, and PPAR-gamma along with a drop in the protein expression of SREBP-2. Collectively, our data indicate that glucose at high concentrations may regulate intestinal cholesterol transport and metabolism in Caco-2/15 cells, thus suggesting a potential influence on the cholesterol absorption process in Type 2 diabetes.