O-099 The use of cumulus cells (CCs) to select spermatozoa for intracytoplasmic sperm injection improves blastocyst development and quality

Study question

Is there a role for sperm selection based on the capacity to pass through cumulus oophorous column in improving the laboratory outcomes in ICSI cycles?

Summary answer

A higher rate of blastocyst formation and quality are obtained with the use of CCs to select spermatozoa for ICSI compared to conventional density gradients.

What is known already

The sperm selection for ICSI is an operator-dependent procedure based on sperm morphology and motility. ICSI bypasses all natural barriers of sperm selection, which may impact embryo development.

During natural fertilization, only the spermatozoa that pass-through cumulus cells will have the chance to fertilize the egg. Spermatozoa capable of traverse COCs have better morphology, higher chromatin integrity and greater acrosomal reaction. Hyaluronic acid is an important component of these cells and plays a key role in the selection of spermatozoa with intact DNA. However, there is scarce data regarding this selection method for ICSI on the development of the embryo.

Study design, size, duration

This is a prospective randomized sibling oocyte pilot study (February-December 2021). A total of 996 metaphase II (MII) oocytes were randomized into two groups. In the control group (Group 0, n = 489 MII), ICSI was performed with sperm selected by conventional density gradients. In the study group (Group 1, n = 507 MII) the oocytes were microinjected with sperm selected through CCs. The main outcome was blastocyst formation rate and quality. Reproductive results were analyzed as secondary outcomes.

Participants/materials, setting, methods

Ninety-eight couples undergoing ICSI (private center) with ≥6 fresh own MII obtained after ovarian stimulation, embryo culture until blastocyst stage and ejaculated sperm samples were included in the study.

All seminal samples were processed using density gradients and those in the study group were additionally passed through CCs (the patient's own CCs were used in all cases).

Fertilization and day 5 blastocyst formation rates were assessed. Embryo quality was scored according to Gardner's criteria.

Main results and the role of chance

Data was similar with regards to cause of infertility, maternal age (36.47 vs 36.63 y.o.), sperm count (60.53 vs 58.25 mill/ml) and progressive motility (57.45 vs 57.50%) between group 0 vs 1, respectively.

Fertilization rate was similar between groups (74.0% vs 78.7%; p = 0.419. Group 0 vs 1, respectively). However, the blastocyst formation rate was significantly higher in the study group compared to control (70.9% vs 60.1%; p = 0.002). In addition, high-quality blastocyst rate was significantly higher in the CCs compared to the control group (49.6% vs 38.5%; p = 0.003). After the analysis of 145 treatments (131 frozen vs 14 fresh transfers) the cumulative clinical pregnancy rate in the study group was 47.2%, higher than in the control group (32.1%), but without reaching statistical difference (p = 0.07).

Limitations, reasons for caution

This is an exploratory study, aimed to evaluate the effectiveness of CCs as a more “physiologic” selection of spermatozoa for ICSI treatments in terms of laboratory outcomes (blastocyst formation rate and quality). Albeit not reaching statistical significance, the higher cumulative pregnancy rate in the study group seems clinically relevant.

Wider implications of the findings

Our results suggest that CCs can select more competent sperm for ICSI. This “physiologic-resembling”, operator-independent selection method has the potential of increasing pregnancy outcomes in ICSI cycles, pending of confirmation in larger studies including cumulative embryo-transfer cycles.

Trial registration number

NA

Interdisciplinary combined sacrocolporectopexy: Results after one-year follow-up

Objective

Multicompartmental pelvic floor descensus typically affects women after menopause, leading to a combination of faecal and urinary incontinence, dyspareunia, and evacuation disorders. The aim of this study was to access postoperative quality of life and complications as well as outcome after one-year follow-up after operation of multicompartmental pelvic floor prolapse (POP).

Methods

All Patients undergoing ventral mesh rectopexy by surgical department and anterior mesh sacrocolpopexy by gynecologists at the same time between 2015 and 2020 were enrolled. The study is a retrospective cohort study approved by the local Ethics committee. Follow-up was scheduled at 6 weeks, 6, and 12 months and consisted of clinical examination and questionnaires. Perioperative and long-time morbidity was assessed according to the Clavien-Dindo classification. Quality of life and patients’ satisfaction were evaluated at each consultation.

Results

Twenty-seven patients were included. All patients were seen at one-year follow-up.

Demographic and clinical features are reported in Table 1. Preoperatively, 22 patients (81.5%) were diagnosed with stage II-III (POP-Q) prolapse and severe multicompartment descensus detected on Magnetic Resonance (MR). Laparoscopic surgery was performed in 92.5% of cases and intraoperative conversion was necessary in 2 cases. In 15 cases (55%) a Dynamesh® Visible, in 11 cases (41%) a Gynamesh®, and in one (4%) case a Surgipro™ Mesh was used. No severe complications (Clavien-Dindo >=3) occurred postoperatively. 90-day mortality was 0%. Intraoperatively, a total of 1 vaginal, and 2 bladder lesions were corrected and healed without consequences. At 1 year, patients reported a high level of satisfaction and massive improvement of QoL (8.5 Pt. VAS Scale). During follow-up, one patient had to be reoperated because of incisional hernia and one to cover vaginal mesh exposure. A tension free vaginal tape (TVT) had to be inserted in 4 patients (15%) due to new onset of urinary incontinence. Symptomatic recurrence of prolapse did not occur.

Conclusion

Interdisciplinary combined sacrocolporectopexy is an effective therapy of multicompartmental pelvic floor descensus. It is a safe procedure with low perioperative morbidity and high patients’ satisfaction. Therefore, it might be the procedure of choice to correct multicompartmental POP.

Determination of Atrazine in Water by Magnetic Particle Immunoassay: Collaborative Study

A collaborative study was performed to determine mean recovery and precision for analysis of atrazine in drinking and surface waters by immunoassay. The study design was based on the blind duplicate test plan for collaborative studies. Three blank waters (municipal drinking water, well water, and surface water) were spiked at 3 atrazine levels. Two water samples with naturally incurred atrazine loads were also spiked with atrazine at 3 levels. In the enzyme-linked immunoassay method, the water sample is mixed with a pesticide–enzyme conjugate and added to paramagnetic particles with triazine-specific antibodies attached. After separation of antibody-bound atrazine and atrazine–enzyme conjugate from free components, the bound enzyme conjugate catalyzes a reaction producing a colored end product. The color developed is inversely proportional to the original concentration of atrazine in the water sample. Fourteen laboratories participated in the collaborative study. Data were analyzed for repeatability and reproducibility, and average recoveries at the spike levels were calculated. Over the concentration range tested, the mean recovery of atrazine spiked into blank and pesticide-contaminated waters was 104%. Overall RSDRaveraged about 40% for atrazine concentrations near the method detection limit (0.05 μg/L) and about 15% at concentrations above 5 times the detection limit (0.25 μg/L). Corresponding single-analyst RSDr values were 24 and 10%. Recovery and precision for the 3 blank water matrixes and the waters that had been naturally contaminated with atrazine showed no significant differences. The magnetic particle immunoassay

Survival after resection of appendiceal carcinoma by hemicolectomy and less radical than hemicolectomy: a population-based propensity score matched analysis

AIM

The operative treatment for non-metastatic appendiceal carcinoma is controversial despite the recommendation of right hemicolectomy (RH) by many researchers. The aim of this population-based study was to compare outcomes after RH and less radical resection than right hemicolectomy (LRH).

METHOD

A total of 1144 patients who underwent resection with additional lymphadenectomy of Stages I-III appendiceal carcinoma from 2004 to 2012 were identified in the Surveillance, Epidemiology and End Results database. Overall survival (OS) and cancer-specific survival (CSS) after RH and LRH were assessed by unadjusted and risk-adjusted Cox regression analysis and by propensity score matched analysis.

RESULTS

A total of 855 (74.7%) patients underwent RH and 289 (25.3%) underwent LRH. In an unadjusted analysis, survival after LRH and RH did not differ in OS [hazard ratio (HR) 0.95, 95% CI 0.71-1.26, P = 0.707] and CSS (HR 0.95, 95% CI 0.69-1.32, P = 0.762). The 5-year OS and CSS in patients who underwent RH were 71.6% (95% CI 67.8-75.6%) and 76.4% (95% CI 72.8-80.3) compared with 73.8% (95% CI 67.9-80.2) and 78.7% (95% CI 73.2-84.7) in patients with LRH, respectively. No relevant difference in survival between LRH and RH could be observed in a multivariable analysis (OS, HR 0.90, 95% CI 0.65-1.25, P = 0.493; CSS, HR 0.87, 95% CI 0.60-1.26, P = 0.420) and after propensity score adjusted analysis (OS, HR 0.87, 95% CI 0.62-1.22, P = 0.442; CSS, HR 0.97, 95% CI 0.67-1.40, P = 0.883).

CONCLUSIONS

In this retrospective analysis, survival after RH for non-metastatic appendiceal carcinoma was not statistically significantly superior to LRH. Hence, LRH with lymphadenectomy might be sufficient for treatment of non-metastatic appendiceal carcinoma.

First experiences with pudendal nerve stimulation in fecal incontinence: a technical report

Sacral nerve stimulation (SNS) is an established treatment for refractory lower urinary tract and bowel dysfunction. In some urological patients, SNS does not have satisfactory results. Pudendal nerve stimulation (PNS) has recently been proposed for these patients and successfully tested. Given the sometimes unsatisfactory results after SNS in fecal incontinence (FI), we tested PNS on patients suffering from FI. We used the device and implantation technique described by Spinelli et al. By making a slight change in the device, we developed a quick and easy-to-use method for successful PNS implantation, based on electrophysiological response. We present the results of a feasibility study, in which we tested the effectiveness of PNS with our modified implantation technique on 2 patients, with very satisfactory early results in a 4-month follow-up.

[Rectal pocket syndrome after stapled haemorrhoidopexy]

We report the case of a 41-year-old female patient who presented in the emergency department with recurrent pain in the lower abdomen 3 years after haemorrhoidopexy (Longo's procedure). At clinical examination a space-occupying mass between the rectum and the vagina was present which was identified as a stool-loaded diverticulum of the rectum by magnetic resonance imaging. Using a perineal approach the diverticulum could be excised at its base and the defect of the mucosa was closed transanally with sutures. A diverticulum of the rectum is a rare complication (2.5%) after stapled haemorrhoidopexy. In the diagnostic of complications after Longo's haemorroidopexy the MRI constitutes an excellent auxiliary modality.

Prolonged treatment with the beta3-adrenergic agonist CL 316243 induces adipose tissue remodeling in rat but not in guinea pig: 2) modulation of glucose uptake and monoamine oxidase activity

Beta3-adrenergic agonists are well-recognited to promote lipid mobilisation and adipose tissue remodeling in rodents, leading to multilocular fat cells enriched in mitochondria. However, effects of beta3-adrenergic agonists on glucose transport are still controversial. In this work, we studied in white adipose tissue (WAT) the influence of sustained beta3-adrenergic stimulation on the glucose transport and on the mitochondrial monoamine oxidase (MAO) activity. As one-week administration of CL 316243 (CL, 1 mg/kg/d) induces beta-adrenergic desensitization in rat but not in guinea pig adipocytes, attention was paid to compare these models. When expressing glucose uptake as nmoles of 2-deoxyglucose/100 mg cell lipids, maximally stimulated uptake was increased in adipocytes of WAT from treated rats but not from treated guinea pigs. However, basal hexose uptake was also increased in CL-treated rats and, as a consequence, the dose-dependent curves for insulin stimulation were similar in control and CL-treated rats when expressed as fold increase over basal. Insulin-induced lipogenesis was unchanged in rat or guinea pig adipocytes after CL-treatment. The glucose carriers GLUT4 and corresponding mRNA were increased in subcutaneous WAT or in brown adipose tissue (BAT) but not in visceral WAT or muscles of CL-treated rats. There was an increase of MAO activity in WAT and BAT, but not in liver, of CL-treated rats while no change was detected in guinea pigs. These findings show that only rat adipocytes, which are beta3-adrenergic-responsive, respond to chronic beta3-AR agonist by an increase of GLUT4 content and MAO activity, despite a desensitization of all beta-adrenoceptor subtypes.

The release of soluble VAP-1/SSAO by 3T3-L1 adipocytes is stimulated by isoproterenol and low concentrations of TNFalpha

Plasma level of the protein VAP-1/SSAO (Vascular Adhesion Protein-1/Semicarbazide-Sensitive Amine Oxidase) is increased in diabetes and/or obesity and may be related to vascular complications associated to these pathologies. The aim of this work was to complete a preceding study where we described the role played by some hormones or metabolites, implicated in diabetes and/or obesity, in the regulation of the release of VAP-1/SSAO by 3T3-L1 adipocytes. Here we focused on the previously observed effect produced by TNFalpha in the release of VAP-1/SSAO and studied the effect of a beta-adrenergic compound, isoproterenol. Both compounds stimulated the release of VAP-1/SSAO to the culture medium but had a different effect on the VAP-1/SSAO membrane form. While TNFalpha produced a decrease on VAP-1/SSAO membrane form content, isoproterenol did not modify it. We thus observed two different ways of regulation of the release of VAP-1/SSAO by 3T3-L1 adipocytes by metabolites implicated in diabetes and adipose tissue physiopathology. Our work permits a better understanding of this increased plasma VAP-1/SSAO levels observed in diabetes.

Stimulation of glucose transport by semicarbazide-sensitive amine oxidase activity in adipocytes from diabetic rats

Semicarbazide-sensitive amine oxidase (SSAO) is highly expressed in adipose cells, and substrates of SSAO such as benzylamine in combination with low concentrations of vanadate strongly stimulate glucose transport and GLUT4 recruitment in mouse 3T3-L1 adipocytes and in isolated rat adipocytes. Here we examined whether this combination of molecules also stimulates glucose transport in adipocytes from streptozotocin-induced diabetic rats and from Goto-Kakizaki diabetic rats. As previously reported, adipocytes obtained from streptozotocin-induced diabetic rats, showed a reduced stimulation of glucose transport in response to insulin. Under these conditions, the combination of benzylamine and vanadate caused a marked stimulation of glucose transport that was similar to the stimulation detected in control adipocytes. Adipocytes isolated from Goto-Kakizaki diabetic rats also showed a defective response to insulin; however, acute incubation in the presence of benzylamine and vanadate stimulated glucose transport in these cells to the same extent than in adipocytes from non-diabetic rats. These data indicate that adipocytes obtained from two different models of animal diabetes do not show resistance to the activation of glucose transport by SSAO activity, which is in contrast to the well reported resistance to insulin action. It seems to suggest that SSAO activity in combination with vanadate triggers a glucose transport-activating intracellular pathway that remains intact in the diabetic state. Further, our data support the view that the combination of benzylamine and vanadate could be an effective therapy in diabetes.

Adipocytes release a soluble form of VAP-1/SSAO by a metalloprotease-dependent process and in a regulated manner

AIMS/HYPOTHESIS

Vascular adhesion protein-1 (VAP-1), which is identical to semicarbazide-sensitive amine oxidase (SSAO), is a dual-function membrane protein with adhesion properties and amine oxidase activity. A soluble form of VAP-1 is found in serum, where concentrations are enhanced in diabetes and obesity. In vitro, soluble VAP-1 enhances lymphocyte adhesion to endothelial cells, thus possibly participating in the enhanced lymphocyte adhesion capacity that is implicated in the cardiovascular complications associated with diabetes or obesity. In both, the tissue origin of the soluble VAP-1/SSAO is unknown. We examined whether adipose tissue, which has abundant expression of VAP-1/SSAO, is a source of soluble VAP-1.

METHODS

We detected VAP-1/SSAO in plasma of diabetic animals, with or without VAP-1 immunoprecipitation, and in culture medium from 3T3-L1 adipocytes and human adipose tissue explants. VAP-1 protein glycosylation was measured.

RESULTS

Diabetic and obese animals have increased plasma SSAO activity associated with VAP-1 protein. We also found that 3T3-L1 adipocytes and human adipose tissue explants release a soluble form of VAP-1/SSAO, which derives from the membrane. The release of soluble VAP-1 was enhanced by exposure of murine and human adipocytes to TNF-alpha and blocked by batimastat, a metalloprotease inhibitor. Partial ablation of adipose tissue reduced plasma SSAO activity in normal and diabetic rats.

CONCLUSIONS/INTERPRETATION

Adipose cells are a source of soluble VAP-1/SSAO released by shedding of the membrane form. The release of SSAO is regulated by TNF-alpha and insulin. By releasing VAP-1/SSAO, adipose cells could contribute to the atherogenesis and vascular dysfunction associated with diabetes and obesity.

Combined treatment with benzylamine and low dosages of vanadate enhances glucose tolerance and reduces hyperglycemia in streptozotocin-induced diabetic rats

Semicarbazide-sensitive amine oxidase (SSAO) is highly expressed in adipose cells, and substrates of SSAO, such as benzylamine, in combination with low concentrations of vanadate strongly stimulate glucose transport and GLUT4 recruitment in 3T3-L1 and rat adipocytes. Here we examined whether acute and chronic administration of benzylamine and vanadate in vivo enhances glucose tolerance and reduces hyperglycemia in diabetic rats. Acute intravenous administration of these drugs enhanced glucose tolerance in nondiabetic rats and in streptozotocin (STZ)-induced diabetic rats. This occurred in the absence of changes in plasma insulin concentrations. However, the administration of benzylamine or vanadate alone did not improve glucose tolerance. The improvement caused by benzylamine plus vanadate was abolished when rats were pretreated with the SSAO-inhibitor semicarbazide. Chronic administration of benzylamine and vanadate exerted potent antidiabetic effects in STZ-induced diabetic rats. Although daily administration of vanadate alone (50 and 25 micromol x kg(-1) x day(-1) i.p.) for 2 weeks had little or no effect on glycemia, vanadate plus benzylamine reduced hyperglycemia in diabetic rats, enhanced basal and insulin-stimulated glucose transport, and upregulated GLUT4 expression in isolated adipocytes. In all, our results substantiated that acute and chronic administration of benzylamine with low dosages of vanadate have potent antidiabetic effects in rats.

Amine oxidase substrates mimic several of the insulin effects on adipocyte differentiation in 3T3 F442A cells

We have previously reported that substrates of monoamine oxidase (MAO) and semicarbazide-sensitive amine oxidase (SSAO) exert short-term insulin-like effects in rat adipocytes, such as stimulation of glucose transport. In the present work, we studied whether these substrates could also mimic long-term actions of insulin. Adipose differentiation of 3T3 F442A cells, which is highly insulin-dependent, served as a model to test the effects of sustained administration of amine oxidase substrates. Daily treatment of confluent cells with 0.75 mM tyramine (a substrate of MAO and SSAO) or benzylamine (a substrate of SSAO) over 1 week caused the acquisition of typical adipocyte morphology. The stimulation of protein synthesis and triacylglycerol accumulation caused by tyramine or benzylamine reached one half of that promoted by insulin. This effect was insensitive to pargyline (an MAO inhibitor), but was inhibited by semicarbazide (an SSAO inhibitor) and by N-acetylcysteine (an antioxidant agent), suggesting the involvement of the H(2)O(2) generated during SSAO-dependent amine oxidation. Chronic administration of amine oxidase substrates also induced the emergence of adipose conversion markers, such as aP2, glycerol-3-phosphate dehydrogenase, the glucose transporter GLUT4, and SSAO itself. Moreover, cells treated with amines acquired the same insulin sensitivity regarding glucose transport as adipocytes classically differentiated with insulin. In all, most of the adipogenic effects of amines were additive to insulin. Our data reveal that amine oxidase substrates partially mimic the adipogenic effect of insulin in cultured preadipocytes. Furthermore, they suggest that SSAO not only represents a novel late marker of adipogenesis, but could also be directly involved in the triggering of terminal adipocyte differentiation.

[Perianal mucinous adenocarcinoma. A further reason for histological study of anal fistula or anorectal abscess]

A 39-year-old man came to us for surgical treatment of a hidradenitis suppurativa. Upon excision of a perianal abscess, the diagnosis of a rare tumor, a perianal mucinous adenocarcinoma (pT4, pN 1, MO), was made. An abdominoperineal resection was performed, followed by a combination of adjuvant radiation and chemotherapy. A year after the operation, the patient is doing well without any signs of recurrence. This carcinoma probably arises in the anal glands. It often presents as a perirectal abscess and/or an anal fistula. Therefore, the diagnosis is often delayed. At presentation, the tumor is bigger than 5 cm in diameter in 80% of the cases, and the prognosis is poor. It metastasizes mostly to the superficial inguinal or to the retrorectal lymph nodes. There are only case reports and no comparative studies in the literature. In the last 10 years, the carcinoma has mostly been treated by neoadjuvant radiation and chemotherapy, followed by abdominoperineal resection. Since then, the median survival has increased to 3 years. This is the first case report of a combination of a perianal mucinous adenocarcinoma with a hidradenitis suppurativa.

Semicarbazide-sensitive amine oxidase substrates stimulate glucose transport and inhibit lipolysis in human adipocytes

Semicarbazide-sensitive amine oxidases (SSAO) are widely distributed enzymes scavenging biogenic or exogenous amines and generating hydrogen peroxide. We asked whether human adipose tissue could express SSAO. Since hydrogen peroxide exhibits pharmacological insulin-like effects, we also tested whether its endogenous production by SSAO could mimic several insulin effects on adipocytes, such as stimulation of glucose uptake and inhibition of lipolysis. The benzylamine oxidation by human adipose tissue was inhibited by semicarbazide or hydralazine and resistant to pargyline or selegiline. It was due to an SSAO activity localized in adipocyte membranes. A protein of 100-kDa and a 4-kb mRNA corresponding to SSAO were identified in either mammary or abdominal subcutaneous fat depots. In isolated adipocytes, SSAO oxidized similarly benzylamine and methylamine that dose dependently stimulated glucose transport in a semicarbazide-sensitive manner. Antioxidants also inhibited the benzylamine and methylamine effects. Moreover, the ability of diverse substrates to be oxidized by adipocytes was correlated to their effect on glucose transport. Benzylamine and methylamine exerted antilipolytic effects with a maximum attained at 1 mM. These results show that human adipocytes express a membrane-bound SSAO that not only readily oxidizes exogenous amines and generates H(2)O(2), but that also interplays with glucose and lipid metabolism by exerting insulin-like actions. Based on these results and the fact that variations in plasma levels of the soluble form of SSAO have been previously reported in diabetes, we propose that determination of adipocyte SSAO, feasible on subcutaneous microbiopsies, could bring relevant information in pathologies such as obesity or diabetes.

Multiresidue analysis of cotton defoliant, herbicide, and insecticide residues in water by solid-phase extraction and GC-NPD, GC-MS, and HPLC-diode array detection

A multiresidue procedure was developed for analysis of cotton pesticide and harvest-aid chemicals in water using solid-phase extraction and analysis by GC-NPD, GC-MS, and HPLC-DAD. Target compounds included the defoliants tribufos, dimethipin, thidiazuron; the herbicide diuron; and the insecticide methyl parathion. Three solid-phase extraction (SPE) media, octadecylsilyl (ODS), graphitized carbon black (GCB), and a divinylbenzene-N-vinyl pyrollidine copolymer (DVBVP), were evaluated. On GCB and ODS, recoveries varied depending on compound type. Recoveries were quantitative for all compounds on DVBVP, ranging from 87 to 115% in spiked deionized water and surface runoff. The method detection limit was less than 0.1 microg L(-)(1). SPE with DVBVP was applied to post-defoliation samples of surface runoff and tile drainage from a cotton research plot and surface runoff from a commercial field. The research plot was defoliated with a tank mixture of dimethipin and thidiazuron, and the commercial field, with tribufos. Dimethipin was detected (1.9-9.6 microg L(-)(1)) in all research plot samples. In the commercial field samples, tribufos concentration ranged from 0.1 to 135 microg L(-)(1). An exponentially decreasing concentration trend was observed with each successive storm event.

Substrates of semicarbazide-sensitive amine oxidase co-operate with vanadate to stimulate tyrosine phosphorylation of insulin-receptor-substrate proteins, phosphoinositide 3-kinase activity and GLUT4 translocation in adipose cells

It has been shown that the combination of benzylamine or tyramine and low concentrations of vanadate markedly stimulates glucose transport in rat adipocytes by a mechanism that requires semicarbazide-sensitive amine oxidase (SSAO) activity and H(2)O(2) formation. Here we have further analysed the insulin-like effects of the combination of SSAO substrates and vanadate and we have studied the signal-transduction pathway activated in rat adipocytes. We found that several SSAO substrates (benzylamine, tyramine, methylamine, n-decylamine, histamine, tryptamine or beta-phenylethylamine), in combination with low concentrations of vanadate, stimulate glucose transport in isolated rat adipocytes. Furthermore, SSAO substrates together with vanadate stimulated the recruitment of GLUT4 to the cell surface in isolated rat adipocytes. Benzylamine plus vanadate also stimulated glucose transport and GLUT4 translocation in 3T3-L1 adipocytes. Benzylamine or tyramine in combination with vanadate potently stimulated the tyrosine phosphorylation of both insulin receptor substrate (IRS)-1 and IRS-3. In contrast, benzylamine and vanadate caused only a weak stimulation of insulin receptor kinase. Benzylamine or tyramine in combination with vanadate also stimulated phosphoinositide 3-kinase activity; wortmannin abolished the stimulatory effect of benzylamine and vanadate on glucose transport in adipose cells. Furthermore, the administration of benzylamine and vanadate in vivo caused a rapid lowering of plasma glucose levels, which took place in the absence of alterations in plasma insulin. On the basis of these results we propose that SSAO activity regulates glucose transport in adipocytes. SSAO oxidative activity stimulates glucose transport via the translocation of GLUT4 carriers to the cell surface, resulting from a potent tyrosine phosphorylation of IRS-1 and IRS-3 and phosphoinositide 3-kinase activation. Our results also indicate that substrates of SSAO might regulate glucose disposal in vivo.

High expression of monoamine oxidases in human white adipose tissue: evidence for their involvement in noradrenaline clearance

The clearance of plasma adrenaline and noradrenaline by human adipose tissue suggests the expression of the catecholamine-degrading enzyme monoamine oxidases and of catecholamine transport systems in adipocytes. In the present study, we identified and characterized the monoamine oxidases and an extraneuronal noradrenaline transporter expressed in human adipocytes. Enzyme assays using the monoamine oxidase A/B substrate [14C]tyramine showed that abdominal and mammary human adipocytes contain one of the highest monoamine oxidase activities in the body. Characterization of the enzyme isoforms by inhibition profiles of [14C]tyramine oxidation and Western and Northern blot analyses showed that mRNAs and proteins related to both monoamine oxidases A and B were expressed in adipocytes. Quantification of each enzyme isoform performed by enzyme assay and Western blot showed that monoamine oxidase A was predominant, representing 70-80% of the total enzyme activity. In uptake experiments, the monoamine oxidase substrate [3H]noradrenaline was transported into white adipocytes (Vmax 0.81+/-0.3 nmol/30 min/100 mg of lipid, Km 235+/-104 microM). The inhibition of [3H]noradrenaline uptake by specific inhibitors indicated that white human adipocytes contain an extraneuronal-type noradrenaline transporter. Competition studies of [14C]tyramine oxidation showed that noradrenaline is metabolized by monoamine oxidases in intact cells. In conclusion, the concomitant expression of monoamine oxidases and of a noradrenaline transporter in human white adipocytes supports the role of the adipose tissue in the clearance of peripheral catecholamines. These results suggest that adipocytes should be considered as a previously unknown potential target of drugs acting on monoamine oxidases and noradrenaline transporters.

Role of semicarbazide-sensitive amine oxidase on glucose transport and GLUT4 recruitment to the cell surface in adipose cells

The previous characterization of an abundant population of non-adrenergic imidazoline-I2 binding sites in adipocytes and the recent demonstration of the interplay between these binding sites and amine oxidases led us to analyze the amine oxidase activity in membranes from isolated rat adipocytes. Adipocyte membranes had substantial levels of semicarbazide-sensitive amine oxidase (SSAO). SSAO activity and immunoreactive SSAO protein were maximal in plasma membranes, and they were also detectable in intracellular membranes. Vesicle immunoisolation analysis indicated that GLUT4-containing vesicles from rat adipocytes contain substantial levels of SSAO activity and immunoreactive SSAO protein. Immunotitration of intracellular GLUT4 vesicles indicated that GLUT4 and SSAO colocalize in an endosomal compartment in rat adipocytes. SSAO activity was also found in GLUT4 vesicles from 3T3-L1 adipocytes and rat skeletal muscle. Benzylamine, a substrate of SSAO activity, caused a marked stimulation of glucose transport in isolated rat adipocytes in the presence of very low vanadate concentrations that by themselves were ineffective in exerting insulin-like effects. This synergistic effect of benzylamine and vanadate on glucose transport was totally abolished in the presence of semicarbazide, a specific inhibitor of SSAO. Subcellular membrane fractionation revealed that the combination of benzylamine and vanadate caused a recruitment of GLUT4 to the plasma membrane of adipose cells. The stimulatory effects of benzylamine and vanadate on glucose transport were blocked by catalase, suggesting that hydrogen peroxide production coupled to SSAO activity plays a crucial regulatory role. Based on these results we propose that SSAO activity might contribute through hydrogen peroxide production to the in vivo regulation of GLUT4 trafficking in adipose cells.

Tyramine and vanadate synergistically stimulate glucose transport in rat adipocytes by amine oxidase-dependent generation of hydrogen peroxide

Nonadrenergic imidazoline I2-binding sites colocalize with monoamine oxidase (MAO) in various tissues. As white adipocytes from various species have been reported to be very rich in I2-sites, the authors consider whether these cells show a substantial MAO activity and explore its functional role. Oxidation of [14C]tyramine by rat adipocyte membranes was dependent on both MAO and semicarbazide-sensitive amine oxidase (SSAO). Tyramine oxidation was identical in membranes and in intact adipocytes (Vmax: 11-12 nmol/min/mg protein). A similar effect of MAO and SSAO inhibitors was obtained in both the intact cells and the membranes: half of the activity was sensitive to semicarbazide and the other half more easily inhibited by MAO-A than by MAO-B inhibitors. As the reaction catalyzed by amine oxidases generates H2O2, which mimicks certain insulin effects in adipocytes, we tested whether tyramine oxidation influences glucose transport in adipocytes. One mM tyramine weakly stimulated glucose transport. A clear potentiation of tyramine effect occurred in the presence of 0.1 mM vanadate, ineffective by itself, reaching half-maximal insulin stimulation. This stimulation was sensitive to MAO and SSAO inhibitors and to catalase. The 5-fold activation of glucose transport was accompanied by translocation of GLUT4 transporters to the plasma membrane. This shows that tyramine is readily oxidized by adipocytes and potentiates the effects of vanadium on glucose transport through release of hydrogen peroxide. The role of the amine oxidases, which are highly expressed in adipocytes, allows them to be considered as more than mere scavengers of circulating amines.

Lipolytic and antilipolytic responses of the Siberian hamster (Phodopus sungorus sungorus) white adipocytes after weight loss induced by short photoperiod exposure

Short day photoperiod promotes thermogenesis and extensive weight loss in Siberian hamsters (Phodopus sungorus sungorus). To determine whether a change in hormone-sensitive lipolysis occurs after short-photoperiod exposure, some lipolytic responses were measured on white adipocytes isolated from animals exposed in warm conditions to short or Long daylight photoperiod. The body mass of male Siberian hamsters exposed during 11 weeks to short days (SD; light: dark, 6:18 hr) reached only 50% of those kept in long days (LD; 16: 8 hr). In SD-hamsters, adipose depot mass also represented approximately 50% of the LD group. A lower DNA content was observed in intra-abdominal fat pads of SD-hamsters. Lipolytic responses to noradrenaline, adrenaline, isoproterenol and ACTH were unchanged. However, sensitivity to the beta-3 adrenergic agonist, BRL 37344, was moderately increased. The major component of the adrenergic control of lipolysis was mediated by beta-3 adrenoceptors in both LD- and SD-Siberian hamsters. The limited antilipolytic effect of alpha-2 adrenergic agonists, PYY or insulin was rather surprising in Siberian hamsters since these inhibitory systems are efficient in hibernants and other photoperiod-sensitive rodents. Our results show that, after short photoperiod exposure, white adipose tissue mass and DNA content are reduced, especially in the epididymal fat pad, with only minor changes in the adipocyte sensitivity to lipolytic hormones.

Beta 3-adrenoceptor in guinea pig brown and white adipocytes: low expression and lack of function

In the guinea pig, cold acclimation induced a conversion of unilocular to multilocular adipocytes in interscapular (IS) and retroperitoneal (RP) fat depots but not in the epididymal (EP) fat pad. The conversion was associated with an increase in mitochondriogenesis and the appearance of the uncoupling protein. The maximal lipolytic responses to norepinephrine and dibutyryl adenosine 3',5'-cyclic monophosphate were decreased in IS cells, unchanged in RP cells, and increased in EP cells, suggesting a site-specific regulation of lipolysis at the postreceptor level. beta 3-Adrenergic agonists were not lipolytic regardless of the depot and the thermal environment of the animal. These agents did not inhibit glucose transport and lipogenesis, as was previously reported for rodents. Cloning and sequencing of the guinea pig beta 3-adrenoceptor gene revealed a slightly higher amino acid sequence similarity with the human than with the rodent beta 3-adrenoceptors. beta 3-Adrenoceptor transcripts were present at a very low level in guinea pig adipocytes, and mRNA levels did not increase to a significant extent after cold acclimation. The guinea pig thus differs from rodents by an absence of beta 3-adrenergic effects and by low beta 3-adrenoceptor expression in brown and white adipose tissues.

[Malignant rhabdoid tumor of the kidney in the adult]

Presentation of a malignant rhabdoid renal tumour. This type of sarcoma which occurs commonly during the paediatric age is exceptional in the adult, this being the reason for reviewing this clinical case and its management. The term rhabdoid includes several types of morphologically similar tumours which make analysis and pathological categorization difficult. A description of the classification criteria and likely origin of the tumour is included.