Sonic hedgehog signaling switches the mode of division in the developing nervous system

The different modes of stem cell division are tightly regulated to balance growth and differentiation during organ development and homeostasis, and these regulatory processes are subverted in tumor formation. Here, we developed markers that provided the single-cell resolution necessary to quantify the three modes of division taking place in the developing nervous system in vivo: self-expanding, PP; self-replacing, PN; and self-consuming, NN. Using these markers and a mathematical model that predicts the dynamics of motor neuron progenitor division, we identify a role for the morphogen Sonic hedgehog in the maintenance of stem cell identity in the developing spinal cord. Moreover, our study provides insight into the process linking lineage commitment to neurogenesis with changes in cell-cycle parameters. As a result, we propose a challenging model in which the external Sonic hedgehog signal dictates stem cell identity, reflected in the consequent readjustment of cell-cycle parameters.

MicroRNA expression profiling in blood from fragile X-associated tremor/ataxia syndrome patients

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder associated with FMR1 gene premutation alleles (55-200 CGG repeats). Fragile X-associated tremor/ataxia syndrome clinical core features include action tremor, gait ataxia, cognitive deficits progressing to dementia, and frequently parkinsonism. Although the pathogenic molecular mechanism of FXTAS is not completely understood, the restriction of the phenotype to the FMR1 premutation range has given rise to a model based on a RNA toxic gain-of-function. Since the identification of the first microRNAs (miRNAs) and their role in normal development, several studies have associated them with neurodegenerative diseases such as Parkinson, Alzheimer and Huntington diseases, suggesting that they play a key role in brain development, as well as in its morphogenesis. Herein, we present the characterization of miRNA expression profiles in FXTAS male patients using deep sequencing-based technologies and microarray technology. Deep sequencing analysis evidenced 83 miRNAs that were significantly deregulated whereas microarray analysis showed 31. When comparing these results, 14 miRNAs were found deregulated in FXTAS patients. MiR-424 and miR-574-3p showed significant fold change adjusted P-values in both platforms in FXTAS patients. MiR-424 has been founded substantially and specifically enriched in human cerebral cortical white matter of Alzheimer disease patients, which, together with cerebral atrophy, is a prominent imaging finding in individuals with FXTAS. The study provides the first systematic evidence of differential miRNA expression changes in FXTAS blood samples. Although further studies are necessary to better characterize the miRNA function in FXTAS disorder, our results suggest that they might contribute to its pathogenesis.

Smad2 and Smad3 cooperate and antagonize simultaneously in vertebrate neurogenesis

The transforming growth factor beta (TGF-β) pathway plays key roles in development and cancer. (TGF-β) signaling converges on the Smad2 and Smad3 effectors, which can either cooperate or antagonize to regulate their transcriptional targets. Here we performed in vivo and in silico experiments to study how such cooperativity and antagonism might function during neurogenesis. In vivo electroporation experiments in the chick embryo neural tube show that Smad2 and Smad3 cooperate to promote neurogenesis, as well as the transcription of Smad3 specific targets. Smad2 knockdown enhances neurogenesis and the transcription of Smad3 specific targets. A mathematical model of the TGF-β pathway fits the experimental results and predicts that the proportions of the three different trimeric complexes formed dictates the transcriptional responses of the R-Smads. As such, Smad2 targets are activated solely by the Smad2-Smad2-Smad4 complex, while Smad3 targets are activated both by Smad2-Smad3 Smad4 and Smad3- Smad3-Smad4 trimers. Since we have modeled the Smad responses onto arbitrary genes, we propose that this mechanism might be extended to additional activities of TGF-β in development and disease.

Dorsal-ventral patterning of the neural tube: a tale of three signals

Development of the vertebrate nervous system begins with the acquisition of neural identity from the midline dorsal-ectodermal cells of the gastrulating embryos. The subsequent progressive specification of the neural plate along its anterior-posterior and dorsal-ventral (DV) axes allows the generation of the tremendous variety of neuronal and glial cells that compose the vertebrate central nervous system (CNS). Studies on the development of the spinal cord, the anatomically simplest part of the CNS, have generated most of our current knowledge on the signaling events and the genetic networks that orchestrate the DV patterning of the neural plate. In this review, we discuss the recent advances in our understanding of these events and highlight unresolved questions. We focused our attention on the activity and the integration of the three main instructive cues: Sonic hedgehog, the Wnts and the Bone Morphogenetic Proteins, giving particular attention to the less well understood dorsal signaling events.

Jagged2 controls the generation of motor neuron and oligodendrocyte progenitors in the ventral spinal cord

In the developing spinal cord, motor neurons (MNs) and oligodendrocytes arise sequentially from a common pool of progenitors. However, the genetic network responsible for this neurogenesis to gliogenesis switch is largely unknown. A transcriptome analysis identified the Notch ligand Jagged2 (JAG2) as a Sonic hedgehog-regulated factor transiently expressed in MN progenitors (pMNs). In vivo loss- and gain-of-function experiments show that JAG2 schedules the differentiation of the pMN progenitors. At early developmental stages, Olig2 expressing pMN progenitors that enter the differentiation pathway exclusively generate MNs. At these times, the activation of the Notch pathway by JAG2 maintains selected pMN progenitors in an undifferentiated state by two mechanisms; first it inhibits MN generation by reducing Olig2 proteins levels, and second it directly inhibits the premature generation of oligodendrocyte progenitors (OLPs) by maintaining high levels of Hes5. Later, extinction of JAG2 from the pMN results in the loss of Hes5 expression, heralding the gliogenic phase of pMN progenitors. Strikingly, downregulation of JAG2 in pMN progenitors is sufficient to promote the precocious generation of OLPs. Together these data provide evidence that JAG2 is a key regulator of the timely and ordered generation of two of the defining cell types in the spinal cord, MNs and OLPs.

Canonical BMP7 activity is required for the generation of discrete neuronal populations in the dorsal spinal cord

BMP activity is essential for many steps of neural development, including the initial role in neural induction and the control of progenitor identities along the dorsal-ventral axis of the neural tube. Taking advantage of chick in ovo electroporation, we show a novel role for BMP7 at the time of neurogenesis initiation in the spinal cord. Using in vivo loss-of-function experiments, we show that BMP7 activity is required for the generation of three discrete subpopulations of dorsal interneurons: dI1-dI3-dI5. Analysis of the BMP7 mouse mutant shows the conservation of this activity in mammals. Furthermore, this BMP7 activity appears to be mediated by the canonical Smad pathway, as we demonstrate that Smad1 and Smad5 activities are similarly required for the generation of dI1-dI3-dI5. Moreover, we show that this role is independent of the patterned expression of progenitor proteins in the dorsal spinal cord, but depends on the BMP/Smad regulation of specific proneural proteins, thus narrowing this BMP7 activity to the time of neurogenesis. Together, these data establish a novel role for BMP7 in primary neurogenesis, the process by which a neural progenitor exits the cell cycle and enters the terminal differentiation pathway.

[Conservative treatment of the pectus carinatum]

INTRODUCTION

Pectus carinatum (PC) is a deformity that involves the protrusion of the anterior chest wall. It is 10 times less frequent than pectus excavatum. It has a progressive growth and is more common with men. There are two different types, the lower or condrocorporal which is the most common one, and the upper or condromanubrial. Most of the time there are no cardio-respiratory symptoms.

OBJECTIVE

We present our experience in the orthopedic treatment of the pectus carinatum.

METHOD

Retrospective review of patients treated in our hospital from 2002 until 2009. Patients were treated with observation, aerobic exercises, postural change and/or compression braces. Literature review was performed of the treatment for this pathology.

RESULTS

18 patients have been diagnosed with PC, 16 were men and 2 women. All were treated in a nonoperative way. Only 11 of them used a compression brace. We missed two follow-ups and another has just yet begun to achieve proper results. All the rest have had excellent results with nonoperative treatment. None of them have had a surgical treatment.

CONCLUSION

The PC is a disease that most often is a cosmetic problem, with no impact on a cardio-respiratory level. Classically it has been a surgical entity. In our experience we have found that the orthopedic method is an effective alternative, safe and with a significant reduction in morbidity. But we need the collaboration of the patient to accept and maintain continuity in the use of the prostheses.

[The Spanish Home Enteral Nutrition registry of the year 2009: from the NADYA-SENPE group]

OBJECTIVE

To describe the Home Enteral Nutrition Characteristics (HEN) recorded by the group NADYA-SENPE during 2009.

MATERIAL AND METHOD

collection and analysis of the data voluntary recorded in the HEN registry from the NADYA-SENPE group from January 1st to December 31st.

RESULTS

6.540 HEN patients were registered, 5.11% more than the previous year and 6,649 episodes (3,135 in women, 47,93%) from 32 different hospitals. 6,238 of them (95,38%) were over 14 years. The mean age of the patients under 14 yr was 3,67 ± 2,86 and it was 72,10 ± 16,89 in those over 14 yr group. The base illness registered more frequently was the neurological disorders in 2,732 (41,77%) patients, followed by cancer patients in 1,838; 28,10%. The enteral access route was registered in 1,123 (17,17%) of the episodes, being more frequent the administration by nasogastric tube 562 (50,04%). The mean length of nutritional treatment by episode was 323 days (10,77 months). 606 episodes of HEN ended, being the principal reasons for discontinuing treatment the patient death in 295 (48,68%) occasions. The transition to oral feeding occurred in 219 (36,14%) cases. Patients maintained normal activity in 2162 (32,55%) HEN episodes and 2,468 (37,13%) cases were living "bed-couch". The level of dependence was "total" in 2,598 (39,07%) of the episodes recorded. The nutritional formula was provided by the hospital in 4,183 (62,91%) cases and by the reference pharmacy in 2,262 (el 34,02%). Consumables were provided by the hospital in 3,531 (53,11%) cases.

CONCLUSIONS

The number of HEN patients recorded increased from the year 2008, continuing the gradual growth increase since the start of registration. The characteristics of the patients remain in the same profile as in previous years.

[Transversal study on the prevalence of Metabolic Bone Disease (MBD) and Home Parenteral Nutrition (HPN) in Spain: data from NADYA group]

Patients with intestinal failure who receive HPN are at high risk of developing MBD. The origin of this bone alteration is multifactorial and depends greatly on the underlying disease for which the nutritional support is required. Data on the prevalence of this disease in our environment is lacking, so NADYA-SEMPE group has sponsored this transversal study with the aim of knowing the actual MBD prevalence.

MATERIAL AND METHODS

Retrospective data from 51 patients from 13 hospitals were collected. The questionnaire included demographic data as well as the most clinically relevant for MBD data. Laboratory data (calciuria, PTH, 25 -OH -vitamin D) and the results from the first and last bone densitometry were also registered.

RESULTS

Bone mineral density had only been assessed by densitometry in 21 patients at the moment HPN was started. Bone quality is already altered before HPN in a significant percentage of cases (52%). After a mean follow up of 6 years, this percentage increases up to 81%. Due to retrospective nature of the study and the low number of subjects included it has not been possible to determine the role that HPN plays in MBD etiology. Only 35% of patients have vitamin D levels above the recommended limits and the majority of them is not on specific supplementation.

CONCLUSIONS

HPN is associated with very high risk of MBD, therefore, management protocols that can lead to early detection of the problem as well as guiding for follow up and treatment of these patients are needed.

[Spanish home enteral nutrition (HEN) registry of the year 2008 from the NADYA-SENPE group]

AIM

To present the results of the Spanish home enteral nutrition (HEN) registry of the year 2008 from the NADYA-SENPE group.

MATERIAL AND METHODS

We recorded the HEN registry data from January 1st to December 31st 2008.

RESULTS

The number of patients registered in this period was 6206 (51% male) with up to 6,279 episodes of HEN, from 31 Spanish hospitals. Most of the patients (95%) were older than 14 yr. Mean age was 4.83±3.29 yr in the children group, and 70.75±18.14 yr in the adult group (older than 14 yr). Neurological disorders (39%) and cancer (27%) were the two most prevalent diagnoses. The oral route was the most frequently used (43,4%), followed by nasogastric tube (40,4%), and gastrostomy tube (14,7%). Mean length of treatment was 305,36 days (10 months). The principal reasons for discontinuing treatment were death (43%) and progress to oral diet (40%). Only 33% of the patients had a normal activity level, being limited in different grades in the rest of the patients. Most of the patients required partial (25%) or total help (38%). The enteral formula was provided by the hospital in 65% of the cases and by private pharmacies in 32%. The disposables were provided by the hospital (82,4%) and primary care services (17,2%).

CONCLUSIONS

The number and the age of the patients registered have increased comparing to previous years, with little variations in the rest of analyzed variables. The increase in the length of treatment could reflect misreporting of the weaning process in the registry.

H3K27me3 regulates BMP activity in developing spinal cord

During spinal cord development, the combination of secreted signaling proteins and transcription factors provides information for each neural type differentiation. Studies using embryonic stem cells show that trimethylation of lysine 27 of histone H3 (H3K27me3) contributes to repression of many genes key for neural development. However, it remains unclear how H3K27me3-mediated mechanisms control neurogenesis in developing spinal cord. Here, we demonstrate that H3K27me3 controls dorsal interneuron generation by regulation of BMP activity. Our study indicates that expression of Noggin, a BMP extracellular inhibitor, is repressed by H3K27me3. Moreover, we show that Noggin expression is induced by BMP pathway signaling, generating a negative-feedback regulatory loop. In response to BMP pathway activation, JMJD3 histone demethylase interacts with the Smad1/Smad4 complex to demethylate and activate the Noggin promoter. Together, our data reveal how the BMP signaling pathway restricts its own activity in developing spinal cord by modulating H3K27me3 levels at the Noggin promoter.

Neural stem cells: the need for a proper orientation

Drosophila neuroblasts and mouse radial glial cells can divide asymmetrically to self-renew while producing differentiating daughter cells that contribute to brain growth. Intense research activity in the past few years has started to unveil some of the processes that govern asymmetric division in these two cell types. Here we discuss the case of centrosome asymmetry and the contribution of spindle orientation and non-spindle-related centrosome functions. Although still fragmentary, the emerging picture suggests that both notable parallelisms and striking differences apply.

Wnt won the war: antagonistic role of Wnt over Shh controls dorso-ventral patterning of the vertebrate neural tube

The spinal cord has been used as a model to dissect the mechanisms that govern the patterning of tissues during animal development, since the principles that rule the dorso-ventral patterning of the neural tube are applicable to other systems. Signals that determine the dorso-ventral axis of the spinal cord include Sonic hedgehog (Shh), acting as a bona fide morphogenetic signal to determine ventral progenitor identities, and members of the Bmp and the Wnt families, acting in the dorsal neural tube. Although Wnts have been initially recognized as important in proliferation of neural progenitor cells, their role in the dorso-ventral patterning has been controversial. In this review, we discuss recent reports that show an important contribution of the Wnt canonical pathway in dorso-ventral pattern formation. These data allow building a model by which the ventralizing activity of Shh is antagonized by Wnt activity through the expression of Gli3, a potent inhibitor of the Shh pathway. Therefore, antagonistic interactions between canonical Wnt, promoting dorsal identities, and Shh pathways, inducing ventral ones, would define the dorso-ventral patterning of the developing central nervous system.

[Treatment of lymphatic malformations with OK-432 sclerosis. Our experience]

INTRODUCTION

The elective treatment of lymphatic malformations has always been surgical resection. However sclerotherapy with a variety of substances is being used as an alternative to surgery specially in the last years. The aim of this essay is to present our results using sclerosis with OK-432.

MATERIALS AND METHODS

We have reviewed all patients affected by lymphatic malformation that have been treated by sclerosis with OK-432. Each procedure was performed under general anesthesia by a radiologist and a pediatric surgeon.

RESULTS

Fifteen patients have been treated. On the whole, 36 procedures have been performed, with a mean of 2.4 for each patient. The mean amount of OK-432 injected was 1.5 milligrams (mg) in each procedure. 73% of the patients showed nearly complete or complete response. There were two complications; one of them was a limited bleeding and the other one, a case of high fever resolved by antipyretics and antibiotics. Microcystic or mixed malformations required a higher number of procedures and presented poorer response.

CONCLUSION

Sclerotherapy with OK-432 is an effective and safe treatment for lymphatic malformation specially the macrocystic ones, therefore it should be considered as first line therapeutic option.

Chimeric tRNAs as tools to induce proteome damage and identify components of stress responses

Misfolded proteins are caused by genomic mutations, aberrant splicing events, translation errors or environmental factors. The accumulation of misfolded proteins is a phenomenon connected to several human disorders, and is managed by stress responses specific to the cellular compartments being affected. In wild-type cells these mechanisms of stress response can be experimentally induced by expressing recombinant misfolded proteins or by incubating cells with large concentrations of amino acid analogues. Here, we report a novel approach for the induction of stress responses to protein aggregation. Our method is based on engineered transfer RNAs that can be expressed in cells or tissues, where they actively integrate in the translation machinery causing general proteome substitutions. This strategy allows for the introduction of mutations of increasing severity randomly in the proteome, without exposing cells to unnatural compounds. Here, we show that this approach can be used for the differential activation of the stress response in the Endoplasmic Reticulum (ER). As an example of the applications of this method, we have applied it to the identification of human microRNAs activated or repressed during unfolded protein stress.

[National registry of home enteral nutrition in Spain 2007]

OBJECTIVE

To communicate the results from the registry of Home-Based Enteral Nutrition of the NADYASENPE group in 2007.

MATERIAL AND METHODS

We included every patient in the registry with home enteral nutrition any time from January 1st to December 31st of 2007.

RESULTS

The number of patients with home enteral nutrition in 2007 was 5,107 (52% male) from 28 different hospitals. 95.4% of them were 15 yr or older, with a mean age of 67.96 +/- 18.12, and 4.2 +/- 3.38 among patients aged 14 yr or less. The most common underlying diseases were neurological (37.8%) and neoplastic diseases (29.3%). Enteral nutrition was administered p.o. in most patients (63.5%), followed by nasogastric tube (25.9%), while gastrostomy was only used in 9.2%. The mean time in enteral nutrition support was 9.4 months and the most common reasons for withdrawal were death (58.7%) and switching to oral intake (32%). Activity was limited in 31.4% of patients and 36.01% were house-bound. Most patients needed partial (26.51%) or total (37.68%) care assistance. Enteral formula was provided by hospitals to 69.14% of patients and by pharmacies to 30.17% of them, while disposable material was provided by hospitals to 81.63% and by Primary Care to the remaining patients.

CONCLUSIONS

In 2007, there has been an increase of more than 30% of patients registered with home enteral nutrition comparing with 2006, without any big difference in other data, but a higher proportion of patients with enteral nutrition p.o.

Hedgehog activation is required upstream of Wnt signalling to control neural progenitor proliferation

The canonical Wnt and sonic hedgehog (Shh) pathways have been independently linked to cell proliferation in a variety of tissues and systems. However, interaction of these signals in the control of cell cycle progression has not been studied. Here, we demonstrate that in the developing vertebrate nervous system these pathways genetically interact to control progression of the G1 phase of the cell cycle. By in vivo loss-of-function experiments, we demonstrate the absolute requirement of an upstream Shh activity for the regulation of Tcf3/4 expression. In the absence of Tcf3/4, the canonical Wnt pathway cannot activate target gene expression, including that of cyclin D1, and the cell cycle is necessarily arrested at G1. In addition to the control of G1 progression, Shh activity controls the G2 phase through the regulation of cyclin E, cyclin A and cyclin B expression, and this is achieved independently of Wnt. Thus, in neural progenitors, cell cycle progression is co-ordinately regulated by Wnt and Shh activities.

Measuring in-stream retention of copper by means of constant-rate additions

Human practices entail inputs of nutrients and toxicants such as heavy metals to the fluvial ecosystems. While nutrient dynamics in fluvial ecosystems have been widely studied for over three decades, dynamics of toxicants still remain unclear. In this investigation, the nutrient spiraling concept and associated methodologies to quantify nutrient retention in streams were applied to study copper (Cu) dynamics in streams. The present study aimed to quantify total dissolved Cu retention using a simplified system of indoor channels colonized with fluvial biofilms. Cu retention was studied at sub-toxic concentrations to avoid negative/lethal effects on biota. In addition, Cu retention was compared with retention estimates of a macronutrient, phosphate (PO(4)(3-)), which has been widely studied within the context of the nutrient spiraling concept. The methodology used allowed a successful quantification of Cu and PO(4)(3-) retention. The results showed higher retention efficiency for PO(4)(3-) than for Cu. The biofilm played a key role in retaining both solutes. Although retention efficiency for both solutes was higher in the experiments with colonized substrata compared to uncolonized substrata, we found a positive relationship between uptake rate and chlorophyll-a only for PO(4)(3-). Finally, retention efficiency for both solutes was influenced by water discharge, showing lower retention efficiencies under higher flow conditions. These results suggest that the fate and toxic effects of copper on stream biota may be strongly influenced by the prevailing environmental conditions. Our results indicate that the experimental approach considered can provide new insights into the investigation of retention of toxic compounds in fluvial systems and their controlling mechanisms.

Increased NR2A expression and prolonged decay of NMDA-induced calcium transient in cerebellum of TgDyrk1A mice, a mouse model of Down syndrome

Transgenic mice overexpressing Dyrk1A (TgDyrk1A), a Down syndrome (DS) candidate gene, exhibit motor and cognitive alterations similar to those observed in DS individuals. To gain new insights into the molecular consequences of Dyrk1A overexpression underlying TgDyrk1A and possibly DS motor phenotypes, microarray studies were performed. Transcriptome analysis showed an upregulation of the NR2A subunit of the NMDA type of glutamate receptors in TgDyrk1A cerebellum. NR2A protein overexpression was also detected in TgDyrk1A cerebellar homogenates, in the synaptosome-enriched fraction and in TgDyrk1A primary cerebellar granular neuronal cultures (CGNs). In TgDyrk1A synaptosomes, calcium-imaging experiments showed a higher calcium uptake after NMDA stimulation. Similarly, NMDA administration promoted longer calcium transients in TgDyrk1A CGNs. Taken together, these results show that NMDA-induced calcium rise is altered in TgDyrk1A cerebellar neurons and indicate that calcium signaling is dysregulated in TgDyrk1A mice cerebella. These findings suggest that DYRK1A overexpression might contribute to the dysbalance in the excitatory transmission found in the cerebellum of DS individuals and DS mouse models.

Study of apoptosis-related markers in ram spermatozoa

Certain features of capacitated or frozen-thawed spermatozoa have been considered to be an apoptosis-like phenomenon, and, it has been suggested that the presence of apoptotic sperm in seminal doses could be one of the reasons for poor fertility. The objective of this study was to determine whether phosphatidylserine (PS) translocation, caspase activity and DNA fragmentation, which are considered to be apoptotic markers in somatic cells, occur in ram sperm. Fresh ejaculates and sperm samples in different physiological state (cold-shocked, in vitro capacitated and acrosome-reacted (AR)) were compared. Simultaneous staining with 6-carboxifluorescein diacetate (6-CFDA) and Annexin V-Cy3.18 (AnnV) revealed four different sperm subpopulations in ejaculates. The main subpopulation was composed of viable cells without PS exposure (CFDA+/AnnV-). A total of 40.8% of sperm showed inverted PS, with two levels of alteration: CFDA+/AnnV+ in midpiece ("type I AnnV+"), and in acrosome and midpiece ("type II AnnV+"). The fewest subpopulation contained non-viable cells showing Annexin labelling in the entire cell (CFDA-/AnnV+). Labeling of caspases-3 and -7 by immunocytochemistry revealing different sperm subtypes depending on their localization in apical, equatorial, post-acrosomal regions and tail. The results obtained by western-blot showed, for the first time to our knowledge, that caspase-like proteins are present in fresh ram semen as both inactive and active forms. The proportion of sperm with fragmented DNA [terminal transferase-mediated dUDP nick end-labeling (TUNEL)-positive] were found rarely (2.7+/-0.5%) in all fresh ejaculates involved in this study. The analysis of total activity of both caspases by a fluorometric method showed a decrease in vitro capacitated and acrosome-reacted samples as well as in cryoinjured samples. However, the percentage of TUNEL-positive sperm demonstrating DNA fragmentation was significantly increased after in vitro induced capacitation and acrosome reaction, as well as after cold-shock although this augment was not significant. PS exposure is not totally dependent on caspases in ram spermatozoa as the addition of a caspase inhibitor prevented the increase in PS inversion due to incubation in capacitating conditions but not to the ionophore-induced acrosome reaction or cold-shock.

[Retinal and brain infarctions secondary to acute carotid thrombosis in ovarian hyperstimulation syndrome]

INTRODUCTION

Ovarian hyperstimulation syndrome (OHSS) is an uncommon but potentially life-threatening iatrogenic condition that may appear following ovulation induction in the course of some fertility treatments. This may lead to further complications, some of which may be severe, such as thromboembolic events. Though rarely, it can therefore be a potential cause of stroke.

CLINICAL CASE

We report the case of a 34-year old woman under ovulation induction treatment who developed retinal and brain infarctions secondary to internal carotid occlusion. Oral anticoagulation was administered and recovery was good in spite of the persistence of carotid occlusion in follow-up magnetic ressonance imaging- angiographies.

CONCLUSIONS

This is the first case of carotid occlusion following an OHSS reported in Spain and the eighth one published in the literature. Current literature on cerebrovascular complications in OHSS is also briefly reviewed.