1
|
P-121 Azoospermia: are there neonatal differences regarding the source of sperm for ICSI? Hum Reprod 2022. [DOI: 10.1093/humrep/deac107.116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Study question
In couples with azoospermia undergoing intracytoplasmic sperm injection (ICSI), are neonatal outcomes different depending on sperm origin (epididymal-PESA, testicular-TESA or donor sperm)?
Summary answer
Newborns from PESA or TESA had similar neonatal outcomes. Comparing to donor cases, PESA/TESA cycles didn’t present increased levels of malformation or stillbirth.
What is known already
Since the introduction of ICSI and the demonstration that the spermatozoa derived either from the epididymis or the testis were capable of normal fertilization and pregnancy, it was possible for azoospermic men to father their own children. However, it raised concerns that the quality of spermatozoa in terms of DNA damage or maturation when collected from non-ejaculated semen could differ from that collected from ejaculated and whether sperm of different origins will affect the neonatal outcome and safety of ICSI.
Study design, size, duration
Retrospective cohort study performed at a reproductive medicine center, using data from 359 deliveries from 945 cycles of ICSI of couples with infertility due to azoospermia, performed between 1995 and 2021. Data were collected from electronic records.
Participants/materials, setting, methods
A total of 359 deliveries were divided in 3 groups, according to the sperm source: PESA (n = 138), TESA (n = 139) and DONOR (n = 82). A total of 402 newborns were evaluated: PESA (n = 162); TESA (n = 156); DONOR (n = 84). Neonatal outcomes and congenital malformations were analyzed for singletons, twins and triplets separately. Statistical analysis: Anova, chi-square and Fischer test, considering p < 0.05.
Main results and the role of chance
Comparing the 3 groups (PESA, TESA, and donor sperm), the following results were found: The mean birth weight (BW), length and Apgar score > 7 for singletons and twins did not differ between groups; neither did prematurity or extreme prematurity. According to birth percentile, there was a lower rate of small for gestational age (SGA) newborn in the epididymal group (PESA, 1.5% vs. TESA, 8.5% vs. sperm donor, 5.5%, p = 0.004). Also, in 158 twin births, the number of newborns with low birth weight (<2500g) was significantly smaller in the epididymal group (PESA, 32.9% vs. TESA, 62.5%; donor sperm, 73.1%, p = 0.001). There were three stillbirths in triplets (PESA group). We also found six cases of neonatal mortality (one in singleton pregnancy in TESA group, 3 in twins (two in PESA group and one donor sperm group), and two in triplets (one in TESA and one in PESA groups). The total number of congenital malformations was 8 (2.48%) (PESA n = 1, 0.62%; TESA, n = 2, 1.28%, and donor sperm, n = 5, 5.95%, p = 0.02).
Limitations, reasons for caution
The possibility of incomplete medical records is an important limitation to be considered in retrospective studies. Larger studies are important to better assess the risk of malformation in this population.
Wider implications of the findings
In this study, there were no differences on neonatal outcomes regarding the source of sperm used for ICSI, with PESA, TESA and donor groups, as well as congenital malformation. It showed equally safe options with testis, epididymal or ejaculated sperm for azoospermia treatments.
Trial registration number
not applicable
Collapse
|
2
|
P–463 Patients undergoing elective and onco-fertility preservation respond similarly to controlled ovarian stimulation for fertility preservation. Hum Reprod 2021. [DOI: 10.1093/humrep/deab130.462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Study question
Is the oocyte vitrification response different in patients undergoing elective and onco-fertility preservation?
Summary answer
Patients undergoing elective and onco-fertility preservation seem to respond similarly to controlled ovarian stimulation for fertility preservation.
What is known already
Age persists as the factor with the most significant impact on the prognosis of female fertility. The ovarian reserve can also be threatened by surgical, radiotherapy or chemotherapy procedures. Thus, maternity delay and the increased incidence of malignant diseases are the most jeopardizing conditions for reproductive potential in women. Studies are still conflicting about oocyte freezing results in patients with and without cancer. Some studies suggest worse outcomes in patients with cancer regarding the number of mature vitrified oocytes when compared to healthy patients whether others show similar response to the ovarian stimulation for fertility preservation in both groups.
Study design, size, duration
Observational, cross-sectional, and historical study using data from 367 who underwent oocyte vitrification from a Reproductive Medicine Center, between 2009 and 2018.
Participants/materials, setting, methods
Patients were divided into an elective group (EG; n = 327) and an onco-fertility group (OFG; n = 40). Data were presented as mean ± standard deviation or median and interquartile range (IQR) and absolute and relative frequencies. Chi-square test, Student’s t-test, or Mann-Whitney test were applied. Generalized linear models were used to control confounding factors. Data were adjusted by women age, FSH, and GnRH protocol. The null hypothesis was rejected when p < 0.05. Main results and the role of chance: Patients age in OFG was significantly lower compared to EG (31.3±5.8 vs. 37.0 ±2.9 years; p < 0.01) and also FSH measurement (4.0 [3.3 – 6.2] vs. 9.0 (5.4 – 9.9) mIU/mL; p < 0.01). The presence of a partner was significantly higher in OFG (25 [62.5%] vs. [19.9%]; p < 0.001). GnRH antagonist protocol was used in 80.1% of cycles, and FSH-r was used in 80.4% of cycles. Letrozole was added for 20 breast cancer patients (74%). When adjusting data for age, FSH and Gonadotropin-releasing Hormone (GnRH) protocols, no significant difference in the number of vitrified mature oocytes between the two groups were observed (6.0 [3.0–11.0] vs. 7.0 [3.0–12.0]; p = 0.11). Limitations, reasons for caution: The number of women in the OFG was lower than the EG group. The OFG was composed of different types of tumors in different locations and stages. Thus, it can be questioned whether any patient with a more aggressive tumor might have had a negative impact on the results.
Wider implications of the findings: Healthy patients and patients with cancer seem to respond similarly to ovarian stimulation for fertility preservation. The extensive number of cycles performed for EG in contrast to OFG leads to a reflection on patients who are still not referred for reproductive counseling after a cancer diagnosis.
Trial registration number
Not applicable
Collapse
|
3
|
P–334 CT virtual Histerotomography: a new method for the evaluation of fallopian tube patency and pelvic organs in patients seeking pregnancy. Hum Reprod 2021. [DOI: 10.1093/humrep/deab130.333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Study question
Can computerized virtual histerotomography (CT-HSG) be used for the evaluation of fallopian tube patency and pelvic organs in patients seeking pregnancy? Summary answer: CT-HSG seems to be an adequate test for the evaluation of fallopian tube patency, pelvic organs, and the uterine cavity.
What is known already
CT-HSG is a minimally invasive exam, which diagnoses variations in the female reproductive system, uses low radiation doses and is well tolerated by patients. It simultaneously evaluates the uterine wall, cavity and cervix, tubes, and adjacent pelvic structures. The exam enables virtual navigation, which consists of the endoluminal view of the cervical canal and uterine cavity and allows 3D reconstruction of images. The exam remains underused to assess infertility, but previous studies have shown potential and its use may be widespread.
Study design, size, duration
Retrospective cohort study, that included data from 317 women seeking pregnancy, between January/2019 and January/2021. The CT-HSG was indicated for infertility (90.3%) and RPL (0.9%) investigation, and for the evaluation of tubal stump in patients who were planning the tubal reversal surgery (8.8%). Patients filled out a questionnaire about their pain symptoms and data were collected from electronic records.
Participants/materials, setting, methods
The study analyzed patients’ clinical characteristics and image findings regarding tubes, uterine cavity, and ovaries. For the exam, a catheter was positioned in the cervix, where the contrast medium (iopromide) was injected through an infusion pump at 0.30 ml/s, for a total of 20ml. The tomographic slices were obtained at the 50th second. The CT-HSG images were interpreted by the same gynecologist and radiologist. Data were analyzed using SPSS version 20.0.
Main results and the role of chance
Women and partners’ mean age was 32.7 ± 5.6 and 34.6 ± 7.7 years, respectively, and women’s mean BMI was 28.4 ± 6.4 Kg/m². The pain scale was applied in 103 patients, who reported 5.4±3.2 pain scale scores at the end of the exam. Among the infertile patients 67% were nulliparous. Regarding the exam findings, most of the uterus findings were normal (72.6%). The variations found were uterine malformations (including unicornuate uterus, uterus didelphys, bicornuate uterus, septate uterus, and arcuate uterus), synechia, fibroids, endometrial polyps, adenomyosis and retractions/lateralizations that may suggest endometriosis. The tubal findings on the right/left (%) were: 65/67.5 patent horn; 18.9/17.7 obstructed tubes; 4/41 dilatation/hydrosalpinx and 9.4/9.1 with previous history of tubal ligation or salpingectomy; 1.5% of the tubal evaluation were inconclusive. Eleven from 317 patients had to repeat the exam due to occurrences during the execution (for example, improper catheter positioning, cuff fall, stenosis of the internal cervical ostium, severe pain).The 3D analysis and virtual navigation assist in the findings assessment, in addition to being simpler for the gynecologists evaluation.
Limitations, reasons for caution
The sample size is small due to the exam being a new technique. Patient follow-up and correlation with laparoscopy and hysteroscopy, when indicated, are under studied.
Wider implications of the findings: The exam seems to be promising for assessing infertility, RPL and the tubal stump. Moreover, it may be a good option to hysterosalpingography as it seems to cause less pain and allows to evaluate the ovaries and the uterine contour, added to 3D reconstructions and to virtual uterine navigation.
Trial registration number
Not applicable
Collapse
|
4
|
P–165 Using Artificial Intelligence to Classify Embryo Shape: An International Perspective. Hum Reprod 2021. [DOI: 10.1093/humrep/deab130.164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Study question
Is a pre-trained machine learning algorithm able to accurately detect cellular arrangement in 4-cell embryos from a different continent?
Summary answer
Artificial Intelligence (AI) analysis of 4-cell embryo classification is transferable across clinics globally with 79% accuracy.
What is known already
Previous studies observing four-cell human embryo configurations have demonstrated that non-tetrahedral embryos (embryos in which cells make contact with fewer than 3 other cells) are associated with compromised blastulation and implantation potential. Previous research by this study group has indicated the efficacy of AI models in classification of tetrahedral and non-tetrahedral embryos with 87% accuracy, with a database comprising 2 clinics both from the same country (Brazil). This study aims to evaluate the transferability and robustness of this model on blind test data from a different country (France).
Study design, size, duration
The study was a retrospective cohort analysis in which 909 4-cell embryo images (“tetrahedral”, n = 749; “non-tetrahedral”, n = 160) were collected from 3 clinics (2 Brazilian, 1 French). All embryos were captured at the central focal plane using Embryoscope™ time-lapse incubators. The training data consisted solely of embryo images captured in Brazil (586 tetrahedral; 87 non-tetrahedral) and the test data consisted exclusively of embryo images captured in France (163 tetrahedral; 72 non-tetrahedral).
Participants/materials, setting, methods
The embryo images were labelled as either “tetrahedral” or “non-tetrahedral” at their respective clinics. Annotations were then validated by three operators. A ResNet–50 neural network model pretrained on ImageNet was fine-tuned on the training dataset to predict the correct annotation for each image. We used the cross entropy loss function and the RMSprop optimiser (lr = 1e–5). Simple data augmentations (flips and rotations) were used during the training process to help counteract class imbalances.
Main results and the role of chance
Our model was capable of classifying embryos in the blind French test set with 79% accuracy when trained with the Brazilian data. The model had sensitivity of 91% and 51% for tetrahedral and non-tetrahedral embryos respectively; precision was 81% and 73%; F1 score was 86% and 60%; and AUC was 0.61 and 0.64. This represents a 10% decrease in accuracy compared to when the model both trained and tested on different data from the same clinics.
Limitations, reasons for caution
Although strict inclusion and exclusion criteria were used, inter-operator variability may affect the pre-processing stage of the algorithm. Moreover, as only one focal plane was used, ambiguous cases were interpoloated and further annotated. Analysing embryos at multiple focal planes may prove crucial in improving the accuracy of the model.
Wider implications of the findings: Though the use of machine learning models in the analysis of embryo imagery has grown in recent years, there has been concern over their robustness and transferability. While previous results have demonstrated the utility of locally-trained models, our results highlight the potential for models to be implemented across different clinics.
Trial registration number
Not applicable
Collapse
|
5
|
P–481 COVID–19 pandemic: the emotional impact comparing men and women on assisted reproductive treatment. Hum Reprod 2021. [PMCID: PMC8385931 DOI: 10.1093/humrep/deab130.480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Study question
How has the COVID–19 pandemic affected the psychological aspects of men and women undergoing reproductive treatments?
Summary answer
The women were more emotionally affected due to the COVID–19 pandemic than men, especially increasing anxiety and fear of not achieving pregnancy.
What is known already
COVID–19 pandemic required changes in behavior and plans of most people worldwide, including patients undergoing assisted reproductive treatment (ART). The reproductive societies recommended immediate cessation of all new fertility treatment cycles, arousing different opinions from patients and providers, concerned that a delay of months may affect clinical outcomes. The fear, social distancing and financial insecurity are enough reasons for worry and anguish, and the uncertainty of resuming plans of parenthood make the scenery even more challenging. Therefore, the psychosocial aspects’ evaluation of these patients during the pandemic is fundamental for better comprehension, management, and reception in this especially challenging moment.
Study design, size, duration
Cross-sectional study using data from a centre of reproductive medicine between June and August 2020. The sample was composed of 120 patients (54 men and 66 women), 14.16% undergoing frozen embryo transfer (FET), 77.5% in vitro fertilization (FIV), 1.6% semen freezing collection and 6.6% oocyte freezing.
Participants/materials, setting, methods
The data were extracted from an electronic questionnaire elaborated by the clinical team, which included questions about the patients’ psychological aspects, applied one day before ART. The answers were compared between men and women,and between the types of ART used by each patient. The statistical analysis was made using the program SPSS for Windows. The Chi-Square test was used to compare the study groups, considering p < 0.05 statistically significant.
Main results and the role of chance
It was observed that 23/54 (42%) of men and 42/66 (63%) of women were at least partially emotionally affected by the pandemic (p = 0.027). Comparing feelings between groups (men and women, respectively) the following results were observed: optimistic (42,1% vs 57,9% p = 0.664), hopeful (32,3% vs 67,7%, p = 0.098), anxious (22,6% vs 77,4%, p = 0.004), calm (60,7% vs 39,3%, p < 0.001). Also, 27% of men and 39.3% of women felt more anguished than normal, which was mostly expressed through anxiety (36.7% vs 63.3%, p = 0.113), followed by irritability (54.5% vs 45.5%, p = 0.421), eating habit change (42.5% vs 56.5, p = 0.962) and sleep disorders (28.6% vs 56.5%, p = 0.215). Most patients (96.6%) reported having somebody to share their feelings and didn’t want to be contacted by the clinic’s psychologist (92.5%); 26.3% of couples had their relationship positively affected. Comparing feelings between patients undergoing FET vs FIV, respectively, were found: optimistic (47.0% vs 29.0%, p = 0.142) and anxious (23,5% vs 27.9%, p = 0.70).
Limitations, reasons for caution
The data was collected at one point, in the worst moment of the pandemic in Brazil, which may have influenced some of the answers. The small sample size is due to the lower number of procedures in this period.
Wider implications of the findings: The feelings were similar between groups. However, women seemed to be more fearful of not being able to realize the parenthood dream. Anxiety was the main symptom in both groups, being more prevalent in women. This study reinforces the importance of having mental health professionals in assisted reproductive clinic.
Trial registration number
Not applicable
Collapse
|
6
|
P–107 Does hematological cancer have the same impact on sperm quality as testicular cancer? Hum Reprod 2021. [DOI: 10.1093/humrep/deab130.106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Study question
Does hematological cancer have the same impact on sperm quality as testicular cancer before chemo or radiotherapy? Summary answer: Hematological cancer has no impact on sperm quality before treatment.
What is known already
The deleterious effects of chemo and radiotherapy on testicular function are well known. Furthermore, testicular cancer causes a negative impact on sperm quality, even before treatment, probably due to local action. Hematological cancer, particularly Hodgkin lymphoma, seems to produce inflammatory alterations in the testis. However, it is not clear if hematological cancer can compromise spermatogenesis, as does testicular cancer.
Study design, size, duration
Observational, cross-sectional, retrospective study using data from 360 patients seen at a private infertility clinic between 1992 and 2019 for sperm cryopreservation before treatment. The data were collected from electronic records in a prospective database.
Participants/materials, setting, methods
Seminal samples from patients that cryopreserved semen due to hematological or testicular cancer were compared. Sperm analyses were performed according to the 2010’s World Health Organization (WHO)’s parameters. Seminal volume, total sperm number, sperm concentration, total and progressive motility, and vitality were analysed. In the hematological group, leukemia and lymphoma, and Hodgkin and non-Hodgkin lymphoma were compared. Student t-tests and Chi-Square were used, considering p < 0.05 statistically significant.
Main results and the role of chance
This study included 295 patients with testicular cancer (TEST) and 100 with hematological cancer (HEMAT). Patients that had already started chemo or radiotherapy (4 HEMAT and 12 TEST) were excluded, and 4 HEMAT and 15 TEST were azoospermic or cryptozoospermic (41.7% vs. 53,0%, p = 0,792 ). The other parameters were analysed in 92 HEMAT and 268 TEST. The mean age of the HEMAT group was 28.2 years and 27.9 for the TEST group (p = 0,858). The TEST group had higher rates of oligozoospermia (50.7% vs 31.5%, p = 0.001) and of severe oligozoospermia (29.5% vs 15.2%, p = 0.006) than the HEMAT group. Furthermore, 69.6% HEMAT had normal concentration, compared to 45.9% TEST (p < 0.001). The mean concentration of the HEMAT group was 35 mi/mL, normal according to the WHO’s standards, and the TEST group was 12 mi/mL, below the WHO’s normal standards (p < 0.001). No difference was found when comparing leukemia and lymphoma, or Hodgkin and non-Hodgkin lymphoma.
Limitations, reasons for caution
Besides the fact that this study is retrospective, it also has a small sample size. Furthermore, no analyses regarding sperm morphology were made.
Wider implications of the findings: In this study, testicular cancer had a negative impact on spermatogenesis and sperm quality, whereas hematological cancer did not. However, counseling regarding fertility preservation using sperm banking prior to chemo or radiotherapy should be reinforced in all young cancer patients.
Trial registration number
Not applicable
Collapse
|
7
|
[Advances in diagnostic microbiology : Opportunities and limitations]. Med Klin Intensivmed Notfmed 2017; 112:199-205. [PMID: 28342095 DOI: 10.1007/s00063-017-0275-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 02/20/2017] [Accepted: 02/21/2017] [Indexed: 02/04/2023]
Abstract
In the light of ever increasing problems related to the emergence of multidrug-resistant bacteria, rapid microbiological diagnostics are of growing importance. Timely pathogen detection and availability of susceptibility data are essential for optimal treatment, but are even more crucial for de-escalation of broad spectrum empiric therapies. Medical microbiology is, thus, an integral part of antimicrobial stewardship programs. Traditional microbiological techniques for species identification and susceptibility testing rely on bacterial growth and are, thus, characterized by inherent slowness. Time-to-report is usually 48 h or longer, and typically delays optimization of therapeutic regimens. Constant improvement of available techniques (e. g., molecular methods) and introduction of novel methods (e. g., matrix-assisted laser desorption ionization time-of-flight [MALDI-ToF] mass spectrometry) have fundamentally changed diagnostic procedures. As a consequence, sensitivity and specificity as well as time-to-report have been dramatically improved. In this manuscript, key methodological advances in medical microbiology are discussed, emphasizing consequences for daily management of infectious disease patients.
Collapse
|
8
|
Reisediarrhoe. Dtsch Med Wochenschr 2013; 138:1673-83; quiz 1684-6. [DOI: 10.1055/s-0033-1343306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
9
|
Fabry disease in a female patient due to a de novo point mutation at position 691 of exon 5. Eur J Med Res 2006; 11:306-8. [PMID: 16899426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023] Open
Abstract
Fabry disease is an X-linked lysosomal disorder caused by deficiency of the lysosomal enzyme alpha-galactosidase A. We report on a 32-year-old female patient with an 8-year history of vascular lesions on the hips and periumbilical region and a presumed Fabry disease without positive family history. Ophthalmologic evaluation revealed whorl-like corneal opacities. Echocardiography revealed myxomatous degeneration and prolapse of the mitral valve. DNA analysis of the alpha-galactosidase A gene confirmed the diagnosis of Fabry disease, showing a de novo point mutation at position 691 of exon 5. The patient is now obtaining intravenous enzyme replacement therapy with agalsidase alfa and remains without drug-related reactions.
Collapse
|
10
|
Abstract
HISTORY AND ADMISSION FINDINGS A 32-year-old woman with bilateral corneal opacities was at 9 years of age diagnosed to have reduced activity of the enzyme alpha-galactosidase A. She was admitted to our hospital because of skin lesions that had developed over the last 8 years. INVESTIGATIONS The clinical features included angiokeratomas on the buttocks, hips, and periumbilical region, whorl-like corneal opacity (cornea verticillata), and mitral valve prolapse. Activity of alpha-galactosidase A was reduced to about a quarter of the normal value. Histological examination revealed lipid deposits within the endothelial cells of the skin. Molecular analysis of the alpha-galactosidase A gene revealed a point mutation at nucleotide-position 691 in exon 5 (p.Asp231Asn). TREATMENT AND COURSE Enzyme replacement therapy with agalsidase alfa 0.2 mg/kg body-weight, infused over 40 min every other week, was initiated. So far no side effects due to the infusion therapy have been noted. The therapeutic success (reduction of lipid storage) cannot be assessed as yet. CONCLUSION Fabry disease results from deficient activity of the enzyme alpha-galactosidase A. Affected (hemizygous) males often show the complete spectrum of symptoms and signs and have a deficient alpha-galactosidase A activity. Occasionally milder oligosymptomatic courses are observed, when residual enzyme activity is present. In contrast to previous belief, heterozygous females may be affected in the same manner as hemizygotes and may also have a significantly reduced enzyme activity.
Collapse
|
11
|
Expression of the sodium-driven chloride bicarbonate exchanger NCBE during prenatal mouse development. Gene Expr Patterns 2004; 5:219-23. [PMID: 15567717 DOI: 10.1016/j.modgep.2004.08.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2004] [Revised: 08/07/2004] [Accepted: 08/09/2004] [Indexed: 11/19/2022]
Abstract
In the immature central nervous system (CNS) GABA-mediated excitation is thought to be an important developmental signal. It depends on a high intracellular chloride concentration ([Cl(-)](i)) of the particular neuron. [Cl(-)](i) is a consequence of chloride transport processes across the plasma membrane. The ongoing expression of the KCl-co-transporter KCC2 eventually lowers [Cl(-)](i) in most CNS neurons and thus renders GABA hyperpolarizing. As NCBE, a sodium-dependent chloride-bicarbonate exchanger, also lowers [Cl(-)](i) and may thus modulate the GABA-response, we analyzed its expression during prenatal mouse development before establishment of the mature KCC2 expression. Indeed, NCBE is expressed very early in CNS neurons and precedes the expression of KCC2. Unlike KCC2, NCBE is expressed in the peripheral nervous system and in non-neuronal tissues as the choroid plexus, the dura, and some epithelia including the acid secreting epithelium of the stomach and the duodenal epithelium.
Collapse
|