Phosphorylation by CIPK23 regulates the high-affinity Mn transporter NRAMP1 in Arabidopsis

Manganese (Mn) is essential for plants but is toxic when taken up in excess. To maintain Mn homeostasis, the root Mn transporter natural resistance associated macrophage protein 1 (NRAMP1) cycles from the plasma membrane to endosomes upon phosphorylation. To identify the kinase involved, a split-luciferase screening was carried out between NRAMP1 and kinases of the CIPK family and identified CIPK23 as a partner of NRAMP1. The interaction was confirmed by split-mCitrine bimolecular fluorescence complementation and co-immunoprecipitation assays. In vitro phosphorylation assays pinpointed two CIPK23 target residues in NRAMP1, among which serine 20, important for endocytosis. Interestingly, Mn-induced internalization of NRAMP1 was unaffected by cipk23 mutation suggesting a potential redundancy between CIPK23 and other kinase(s). How CIPK23 could regulate NRAMP1 in response to Mn availability is discussed.

Golgi in and out: multifaceted role and journey of manganese

Manganese (Mn) is pivotal for plant growth and development but little is known about the processes that control its homeostasis in the cell. A spotlight on the pools of intracellular manganese and their cellular function has recently been gained through the characterization of new Mn transporters. In particular, transporters catalyzing the ins and outs of Mn at the various Golgi membranes have revealed the central role of the Golgi pool of Mn in the synthesis of the cell wall and as a reservoir for the numerous cellular Mn-dependent pathways whose calibration relies on a set of Golgi-resident transporters of the BICAT and NRAMP families.

Manganese triggers phosphorylation-mediated endocytosis of the Arabidopsis metal transporter NRAMP1

The NATURAL RESISTANCE-ASSOCIATED MACROPHAGE PROTEIN 1 (NRAMP1) transporter guarantees plant survival of manganese (Mn) deficiency by mediating Mn entry into root cells. Unlike other high-affinity metal transporters, NRAMP1 is only slightly regulated at the transcriptional level. We show here that adequate Mn content in tissues is safeguarded through a tight control of the quantity of NRAMP1 present at the surface of root cells. Depending on Mn availability, an NRAMP1-GFP fusion protein cycles dynamically between the plasma membrane (PM) and endosomal compartments. This involves a clathrin-mediated endocytosis pathway, as disrupting this pathway in auxilin-overexpressor lines prevents NRAMP1 internalization. Mutation of the phosphorylated serine residues 20, 22 and 24 in the cytosol-exposed N terminus of NRAMP1 alters its membrane distribution. Indeed, a phospho-dead mutation stabilizes NRAMP1 at the PM, regardless of the Mn regime, and dramatically reduces plant tolerance to Mn toxicity. Conversely a phosphomimetic mutant is constitutively internalized into endosomes. Together, these data establish that phosphorylation of NRAMP1 is the trigger for its Mn-induced endocytosis and represents the main level of regulation of this transporter. Furthermore, the extent of Mn toxicity observed when interrupting NRAMP1 membrane cycling undermines the dogma that Mn is only marginally toxic to plants.

Intracellular Distribution of Manganese by the Trans-Golgi Network Transporter NRAMP2 Is Critical for Photosynthesis and Cellular Redox Homeostasis

Plants require trace levels of manganese (Mn) for survival, as it is an essential cofactor in oxygen metabolism, especially O2 production via photosynthesis and the disposal of superoxide radicals. These processes occur in specialized organelles, requiring membrane-bound intracellular transporters to partition Mn between cell compartments. We identified an Arabidopsis thaliana member of the NRAMP family of divalent metal transporters, NRAMP2, which functions in the intracellular distribution of Mn. Two knockdown alleles of NRAMP2 showed decreased activity of photosystem II and increased oxidative stress under Mn-deficient conditions, yet total Mn content remained unchanged. At the subcellular level, these phenotypes were associated with a loss of Mn content in vacuoles and chloroplasts. NRAMP2 was able to rescue the mitochondrial yeast mutant mtm1∆ In plants, NRAMP2 is a resident protein of the trans-Golgi network. NRAMP2 may act indirectly on downstream organelles by building up a cytosolic pool that is used to feed target compartments. Moreover, not only does the nramp2 mutant accumulate superoxide ions, but NRAMP2 can functionally replace cytosolic superoxide dismutase in yeast, indicating that the pool of Mn displaced by NRAMP2 is required for the detoxification of reactive oxygen species.

The high-affinity metal Transporters NRAMP1 and IRT1 Team up to Take up Iron under Sufficient Metal Provision

Iron (Fe) and manganese (Mn) are essential metals which, when scarce in the growth medium, are respectively taken up by the root high affinity transporters IRT1 and NRAMP1 in Arabidopsis thaliana. The molecular bases for low affinity transport however remained unknown. Since IRT1 and NRAMP1 have a broad range of substrates among metals, we tested the hypothesis that they might be functionally redundant by generating nramp1 irt1 double mutants. These plants showed extreme Fe-deficiency symptoms despite optimal provision of the metal. Their phenotype, which includes low Fe and Mn contents and a defect of Fe entry into root cells as revealed by Fe staining, is rescued by high Fe supply. Using a promoter swap-based strategy, we showed that root endodermis retains the ability to carry out high affinity Fe transport and furthermore might be important to high-affinity Mn uptake. We concluded that NRAMP1 plays a pivotal role in Fe transport by cooperating with IRT1 to take up Fe in roots under replete conditions, thus providing the first evidence for a low affinity Fe uptake system in plants.

Genome expansion of Arabis alpina linked with retrotransposition and reduced symmetric DNA methylation

Despite evolutionary conserved mechanisms to silence transposable element activity, there are drastic differences in the abundance of transposable elements even among closely related plant species. We conducted a de novo assembly for the 375 Mb genome of the perennial model plant, Arabis alpina. Analysing this genome revealed long-lasting and recent transposable element activity predominately driven by Gypsy long terminal repeat retrotransposons, which extended the low-recombining pericentromeres and transformed large formerly euchromatic regions into repeat-rich pericentromeric regions. This reduced capacity for long terminal repeat retrotransposon silencing and removal in A. alpina co-occurs with unexpectedly low levels of DNA methylation. Most remarkably, the striking reduction of symmetrical CG and CHG methylation suggests weakened DNA methylation maintenance in A. alpina compared with Arabidopsis thaliana. Phylogenetic analyses indicate a highly dynamic evolution of some components of methylation maintenance machinery that might be related to the unique methylation in A. alpina.

[Plant adaptation to nitrogen availability]

Nitrogen is an essential macronutrient for plant development and productivity. The adaptation toward changes in nitrogen availability in the soil is crucial for the immobile plant. Nitrate is the primary nitrogen source in temperate climate. Nitrate transport and assimilation are discussed with emphasis on the adaptation to nitrogen starvation. The integration of nitrogen metabolism with primary and secondary metabolism and the homeostasis with other nutrients are discussed. However, nitrate is not only a nutrient, but also a signaling molecule acting on multiple levels. The molecular players involved in the regulatory network are discussed.

PEP1 of Arabis alpina is encoded by two overlapping genes that contribute to natural genetic variation in perennial flowering

Higher plants exhibit a variety of different life histories. Annual plants live for less than a year and after flowering produce seeds and senesce. By contrast perennials live for many years, dividing their life cycle into episodes of vegetative growth and flowering. Environmental cues control key check points in both life histories. Genes controlling responses to these cues exhibit natural genetic variation that has been studied most in short-lived annuals. We characterize natural genetic variation conferring differences in the perennial life cycle of Arabis alpina. Previously the accession Pajares was shown to flower after prolonged exposure to cold (vernalization) and only for a limited period before returning to vegetative growth. We describe five accessions of A. alpina that do not require vernalization to flower and flower continuously. Genetic complementation showed that these accessions carry mutant alleles at PERPETUAL FLOWERING 1 (PEP1), which encodes a MADS box transcription factor orthologous to FLOWERING LOCUS C in the annual Arabidopsis thaliana. Each accession carries a different mutation at PEP1, suggesting that such variation has arisen independently many times. Characterization of these alleles demonstrated that in most accessions, including Pajares, the PEP1 locus contains a tandem arrangement of a full length and a partial PEP1 copy, which give rise to two full-length transcripts that are differentially expressed. This complexity contrasts with the single gene present in A. thaliana and might contribute to the more complex expression pattern of PEP1 that is associated with the perennial life-cycle. Our work demonstrates that natural accessions of A. alpina exhibit distinct life histories conferred by differences in PEP1 activity, and that continuous flowering forms have arisen multiple times by inactivation of the floral repressor PEP1. Similar phenotypic variation is found in other herbaceous perennial species, and our results provide a paradigm for how characteristic perennial phenotypes might arise.

Perennial plants live for many years and cycle between flowering and vegetative growth. These stages of the life cycle are often initiated by environmental conditions and occur seasonally. However, many herbaceous perennial species such as strawberry, rose, or Arabis alpina contain varieties that flower continuously irrespective of the seasons. Here we characterize this genetic variation in A. alpina and show that five continuously flowering accessions carry independent mutations in the PERPETUAL FLOWERING 1 (PEP1) gene. These mutations impair the activity of the PEP1 floral repressor causing the plants to flower without requirement for winter cold and to flower continuously. This result has interesting parallels with strawberry and rose, where inactivation of a different floral repressor controlling response to day length gives rise to naturally occurring perpetual flowering forms. We also show that PEP1 in A. alpina has a complex duplicated structure that gives rise to two overlapping transcripts. This arrangement differs from the simple structure of PEP1 orthologues in related annual species, such as FLC of Arabidopsis thaliana, suggesting that duplication of PEP1 might contribute to the complex transcriptional patterns associated with PEP1 function in perennials. Our work provides insight into genetic variation contributing to the perennial life history of plants.

Arabidopsis roots and shoots show distinct temporal adaptation patterns toward nitrogen starvation

Nitrogen (N) is an essential macronutrient for plants. N levels in soil vary widely, and plants have developed strategies to cope with N deficiency. However, the regulation of these adaptive responses and the coordinating signals that underlie them are still poorly understood. The aim of this study was to characterize N starvation in adult Arabidopsis (Arabidopsis thaliana) plants in a spatiotemporal manner by an integrative, multilevel global approach analyzing growth, metabolites, enzyme activities, and transcript levels. We determined that the remobilization of N and carbon compounds to the growing roots occurred long before the internal N stores became depleted. A global metabolite analysis by gas chromatography-mass spectrometry revealed organ-specific differences in the metabolic adaptation to complete N starvation, for example, for several tricarboxylic acid cycle intermediates, but also for carbohydrates, secondary products, and phosphate. The activities of central N metabolism enzymes and the capacity for nitrate uptake adapted to N starvation by favoring N remobilization and by increasing the high-affinity nitrate uptake capacity after long-term starvation. Changes in the transcriptome confirmed earlier studies and added a new dimension by revealing specific spatiotemporal patterns and several unknown N starvation-regulated genes, including new predicted small RNA genes. No global correlation between metabolites, enzyme activities, and transcripts was evident. However, this multilevel spatiotemporal global study revealed numerous new patterns of adaptation mechanisms to N starvation. In the context of a sustainable agriculture, this work will give new insight for the production of crops with increased N use efficiency.

Nitrogen signalling in Arabidopsis: how to obtain insights into a complex signalling network

It is well known that nitrogen (N) and N status can be sensed by plants to regulate their development, physiology, and metabolism. Based on approaches efficiently used for fungi and algae, plant researchers have been trying, but with little success, to elucidate higher plants N signalling for several years. Recently, the use of new strategies such as transcriptomics, comparative reverse genetics, and new forward genetic screens have unravelled some players within the complex plant N signalling network. This review will mainly focus on these recent advances in the molecular knowledge of N sensing in plants such as the dual function of the nitrate transporter CHL1, the roles of the transcription factors LBD37/38/39 and NLP7 or of the CIPK8/23 kinases, as well as the implication of small RNAs, which are at last opening doors for future research in this field.

The nodule inception-like protein 7 modulates nitrate sensing and metabolism in Arabidopsis

Nitrate is an essential nutrient, and is involved in many adaptive responses of plants, such as localized proliferation of roots, flowering or stomatal movements. How such nitrate-specific mechanisms are regulated at the molecular level is poorly understood. Although the Arabidopsis ANR1 transcription factor appears to control stimulation of lateral root elongation in response to nitrate, no regulators of nitrate assimilation have so far been identified in higher plants. Legume-specific symbiotic nitrogen fixation is under the control of the putative transcription factor, NIN, in Lotus japonicus. Recently, the algal homologue NIT2 was found to regulate nitrate assimilation. Here we report that Arabidopsis thaliana NIN-like protein 7 (NLP7) knockout mutants constitutively show several features of nitrogen-starved plants, and that they are tolerant to drought stress. We show that nlp7 mutants are impaired in transduction of the nitrate signal, and that the NLP7 expression pattern is consistent with a function of NLP7 in the sensing of nitrogen. Translational fusions with GFP showed a nuclear localization for the NLP7 putative transcription factor. We propose NLP7 as an important element of the nitrate signal transduction pathway and as a new regulatory protein specific for nitrogen assimilation in non-nodulating plants.

The "Remodelling Technique" in the Treatment of Wide Neck Intracranial Aneurysms. Angiographic Results and Clinical Follow-up in 56 Cases

SUMMARY

The main factor limiting endovascular treatment of intracranial aneurysms is the shape of the aneurysmal sac, particularly the width of the neck. In this study we present a new technique to occlude wide neck aneurysms that involve the temporary inflation of a non-detachable balloon in front of the aneurysm neck during each coil placement. The aim of the study is to present the feasibility, efficacy and safety of this "remodelling technique" (RT) compared to that of "normal" GDC treatment. We selected 56 aneurysms in 54 patients for treatment with the RT. Thirty-seven (70%) of the patients presented with subarachnoid haemorrhage. Twenty-five (45%) of the aneurysms were located at the vertebrobasilar artery, 24 (43%) at the internal carotid artery, and seven at the level of smaller arteries. Treatment was achieved in 52 aneurysms in 50 patients. Two aneurysms which were initially not completely occluded underwent a second treatment using the RT. Final results (i.e. the last follow-up angiography or results at the end of the treatment for the cases that have not yet had follow-up) consisted of total occlusion in 40 cases (77%), subtotal occlusion in nine cases (17%), and incomplete occlusion in three cases (6%). Angiographic evidence of clotting was observed during the procedure in three cases, resulting in one permanent deficit (quadranopia). Rupture of the aneurysmal sac occurred during the procedure in three cases, all of which were asymptomatic in the follow-up. Thus, morbidity due to the technique was 1/52 (1%) and mortality was 0/56 patients. The remodelling technique allowed the treatment of 52 wide neck or badly shaped aneurysms that were not treatable without this technique. The results of occlusion with the RT seem better than those in our series of normal GDC treatment, and complications related to the technique are fewer. This technique thereby extends the spectrum of treatable aneurysms without increasing the risk incurred by treatment.

Basilar artery occlusion in a child: "clot angioplasty" followed by thrombolysis

Basilar artery occlusions are rare but have a very poor prognosis. Intra-arterial thrombolysis may produce recanalization and better clinical outcome. A short delay between the onset of symptoms and thrombolysis is considered essential for successful recanalization and for the smallest possible risk of haemorrhagic complications. We present a case of basilar artery occlusion in an 8-year-old child, which was treated by "clot angioplasty" followed by intra-arterial thrombolysis. Thirty hours after progressive alteration of consciousness, speech disturbances and left arm paresis, the child became comatose with decerebrate rigidity. A CT scan showed parenchymal ischaemic lesions. Angiography (performed 36 h after the onset of symptoms) showed a total occlusion of the basilar artery. A clot angioplasty was performed by placing a balloon catheter within the thrombus and inflating it several times in the occluded segment of the basilar artery. Thrombolysis was then performed through the balloon catheter. The basilar artery was only partially recanalized at the end of the procedure, but the perforating arteries of the brain stem had reappeared on angiography. Three months later the child had completely recovered to a normal clinical status. In conclusion, the very poor natural prognosis of basilar artery occlusion requires aggressive management. Recanalization of the basilar artery may be performed even late after the onset of symptoms. Clot angioplasty allows partial recanalization, which may increase the efficiency of thrombolysis.

Long-term angiographic follow-up of 169 intracranial berry aneurysms occluded with detachable coils

PURPOSE

To evaluate the stability of aneurysm occlusion at follow-up angiography after endovascular treatment (EVT) with detachable coils in intracranial berry aneurysms.

MATERIALS AND METHODS

A total of 203 berry aneurysms (< 1.5 cm) were treated with EVT. Follow-up angiography at least 3 months later was performed in 169 cases.

RESULTS

Complete occlusion of the aneurysm sac and neck was achieved in 148 aneurysms, subtotal occlusion in 18, and incomplete occlusion in three. Recurrence occurred between 3 and 40 months in 20 (14%) of the 148 totally occluded aneurysms. A second treatment was performed in five cases, was scheduled in one, and failed in one. The small neck remnant increased in size but did not require any retreatment in three cases, and the size of the neck remnant remained stable in 10 cases. Remnant regrowth occurred in six of the 18 subtotally occluded aneurysms. A second treatment was performed in three. Of the 169 cases, last follow-up angiography showed total occlusion in 133 cases, subtotal in 30, and incomplete in six. No rebleeding occurred.

CONCLUSION

A very small recurrence may be observed at the level of the neck of the aneurysm at long-term follow-up angiography despite achieving total occlusion initially with detachable coils.

Treatment of distal aneurysms of the cerebellar arteries by intraaneurysmal injection of glue

Distal aneurysms of the cerebellar arteries are associated with a poor prognosis, as surgery or embolization with GDCs is very difficult. We report our experience with a new therapeutic method involving intraaneurysmal injection of glue. Three aneurysms were catheterized with a flow-guided microcatheter, and glue was slowly injected into the aneurysms. In two cases, treatment resulted in total occlusion of the aneurysm with preservation of the parent artery. In one case, the aim was to occlude both the aneurysm and parent artery.

[Endovascular treatment of intracranial aneurysms]

Over recent years, an increasing number of patients with intracranial aneurysms are treated by endovascular techniques, which have the advantage of avoiding craniotomy and retraction of cerebral parenchyma, while reducing the postoperative hospital stay. The key concept is that aneurysm is a disease of the arterial wall and that treatment must ideally only concern the vessel. The short-term efficacy of endovascular treatment has been established, especially for the prevention of early rebleeding, but its long-term efficacy has not yet been formally demonstrated due insufficient follow-up. Ideally, the management of intracranial aneurysms should be based on close collaboration between neurosurgeons and interventional neuroradiologists and the approach (conventional surgery or endovascular) should be discussed case by case.

Endovascular treatment of basilar tip aneurysms after direct puncture of the vertebral artery

Basilar aneurysms that are not amenable to standard endovascular treatment via the femoral approach because catheterization is difficult pose a rare but serious problem. We present two cases of basilar tip aneurysms successfully treated by the endovascular route after direct puncture of the right vertebral artery. In both patients, the left vertebral artery was tortuous, small, and irregular, and the ostium of the right vertebral artery was not accessible by the femoral approach.

[Persistent value of intra-arterial fibrinolysis 8 hours or more following central retinal artery occlusion or of its branches]

PURPOSE

To establish that intra-arterial fibrinolysis of the ophthalmic artery can still be efficient 8 hours or more after a central retinal artery occlusion.

MATERIAL AND METHODS

Nine to twenty hours (average 12.5 H) after a loss of vision due to a central retinal artery occlusion or the occlusion of its branches, 7 patients were treated by intra-arterial fibrinolysis. The vision of the affected eye was limited to light perception for four patients, to hand movement at 1 meter for two patients, and to 4/10 P2 for one patient. Under radiological guidance, 300.000 IU of urokinase was injected through a microcatheter placed in the ophthalmic artery (6 patients), or in the facial artery (1 patient); in this case the angiogram showed an occlusion of the internal carotid artery and a retrograde filling of the ophthalmic artery through the facial artery.

RESULTS

We did not observed any complication. The 3 patients who had a vision better than light perception recovered a vision of 10/10 P2. For the others: two patients recovered a vision of 9/10 P2 and 5/10 P2, two did not recover.

CONCLUSION

Fibrinolysis of the ophthalmic artery must ideally be performed as soon as possible, but a recovery is still possible more than 8 hours after the onset of the loss of vision. The time limit is not yet defined but after 24 hours, the chance of improvement seems to be very low.

Embolization of an orbital varix after surgical exposure

We report a case of primary orbital varix treated by embolization with coils after surgical exposure and puncture of the venous ectasia. This method of treatment has the advantage of limiting traumatic dissection and avoiding difficult venous catheterization.

Intracranial berry aneurysms: angiographic and clinical results after endovascular treatment

PURPOSE

To determine the types of aneurysm that may be treated endovascularly with platinum detachable coils.

MATERIALS AND METHODS

Two hundred eight patients with 236 intracranial berry aneurysms underwent endovascular coil embolization; 150 patients had subarachnoid hemorrhage at the time of presentation.

RESULTS

Treatment was performed in 182 patients with 203 (86%) aneurysms (86%). Follow-up angiograms were obtained at 3 months in 160 cases of aneurysm. A second procedure was performed in 18 (11%) of these cases, and a third was performed in one case. Final follow-up results in 152 aneurysms demonstrated total occlusion in 123 (81%) cases, subtotal occlusion in 26 (17%) cases, and incomplete occlusion in three (2%) cases. All patients with subtotally occluded aneurysm were scheduled for later angiographic follow-up and any indicated repeat treatment. Technique-related morbidity rate was 4% (seven patients with permanent neurologic deficits due to clotting). Technique-related mortality rate was 2% (perioperative rupture in two, hematoma due to urokinase perfusion in one, rebleeding of the initial hematoma after excessive uncontrolled anticoagulation in one). Rebleeding occurred in one patient after incomplete occlusion.

CONCLUSION

Endovascular coil embolization seems to be a reliable technique, with good anatomic and clinical results, that provides protection against rebleeding of ruptured aneurysms.

Local intraarterial fibrinolysis of thromboemboli occurring during endovascular treatment of intracerebral aneurysm: a comparison of anatomic results and clinical outcome

PURPOSE

We describe our therapeutic strategy and correlate the anatomic results and clinical outcomes in patients who received immediate fibrinolytic therapy for thromboembolic complications occurring during endovascular treatment of an intracerebral aneurysm.

METHODS

The medical records and angiographic examinations of 19 patients were reviewed. All endovascular procedures were performed with the patients under general anesthesia and fully heparinized. Thirteen patients received an intravenous bolus injection of aspirin. Thromboemboli occurred during catheterization or insertion of embolic material (Guglielmi detachable coils or mechanical detachable spirals) or in the first hours after the intervention. Clot distribution was within the MCA territory in 14 patients, the ACA in three patients, and the basilar trunk in two patients. A continuous intraarterial injection of urokinase was administered immediately, either superselectively distal to the thrombus or selectively within or closely proximal to the thrombus. In nine cases, chemical lysis was combined with mechanical clot fragmentation. Initial anatomic recanalization as well as clinical outcome at 3 months were evaluated.

RESULTS

Ten patients showed complete recanalization and nine patients showed partial recanalization. Fourteen patients had a good clinical recovery. One patient was moderately disabled and two were severely disabled according to their scores on the Glasgow outcome scale. Two patients died, one as a consequence of the preexisting subarachnoid hemorrhage and the other because of a large intracerebral hematoma that developed after fibrinolysis. Of the 14 patients with a good clinical outcome, nine exhibited complete recanalization and five partial recanalization.

CONCLUSION

Pharmacological thrombolysis seems to be a safe and efficient therapy that facilitates the natural fibrinolytic process, increasing the rate of recanalization in thromboembolic events. Clot fragmentation and superselective drug infusion appear to improve the rate of recanalization. Complete recanalization increases the chance of a better clinical outcome; however, clinical outcome does not always correspond to recanalization and vice versa.

[Reconstruction technic in the treatment of wide-neck intracranial aneurysms. Long-term angiographic and clinical results. Apropos of 56 cases]

PURPOSE

The main factor limiting endovascular treatment of intracranial aneurysms is the shape of the aneurysmal sac, particularly the width of the neck. In this study we present a new technique to occlude wide neck aneurysms that involves the temporary inflation of a non-detachable balloon in front of the aneurysm neck during each coil placement. The aim of the study is to present the feasibility, efficacy and safety of this "remodeling technique" (RT) as compared to that of "normal" GDC treatment.

MATERIAL AND METHOD

56 aneurysms in 54 patients were selected for treatment with the RT. Thirty-seven (70%) of the patients presented with subarachnoid hemorrhage. Twenty-five (45%) of the aneurysms were located at the vertebrobasilar artery, 24 (43%) at the internal carotid artery, and seven at the level of smaller arteries.

RESULTS

Treatment was achieved in 52 aneurysms in 50 patients. Two aneurysms which were initially not completely occluded underwent a second treatment using the RT. Final results (i.e. the last follow-up angiography or results at the end of the treatment for the cases that have not yet had follow-up) consisted of total occlusion in 40 cases (77%), sub-total occlusion in nine cases (17%), and incomplete occlusion in three cases (6%). Angiographic evidence of clotting was observed during the procedure in three cases, resulting in one permanent deficit (quadranopia). Rupture of the aneurysmal sac occurred during the procedure in three cases, all of which were asymptomatic in the follow-up. Thus, morbidity due to the technique was 1/52 (0.5%) and mortality was 0/56 patients.

CONCLUSION

The remodeling technique allowed the treatment of 52 wide neck or badly shaped aneurysms that were not treatable without this technique. The results of occlusion with the RT seem better than those in our series of normal GDC treatment, and complications related to the technique are fewer. This technique thereby extends the spectrum of treatable aneurysms without increasing the risk incurred by treatment.

The endovascular approach in the management of patients with multiple intracranial aneurysms

To investigate the role of endovascular treatment we performed a retrospective study of our patients with multiple intracranial aneurysms seen in our institution between October 1992 and March 1995. This period was chosen to study a homogeneous group of patients since the appearance of controlled detachable coils, and to obtain the largest number of patients with angiographic follow-up of the aneurysms treated. We studied 53 patients with a total of 128 aneurysms, in 46 of whom we treated 67 aneurysms by the endovascular approach. Of these, 5 aneurysms in 3 patients were treated by occlusion of the parent vessel and 62 aneurysms in 43 patients with coils, 52 with Guglielmi detachable coils and 10 with mechanically detachable spirals. Complete occlusion was obtained in 58 aneurysms, and partial occlusion in 9. The therapy caused permanent neurological deficit in 3 cases (6.5%), and there was 1 case of rebleeding (incomplete occlusion of the aneurysm). No deaths occurred. All aneurysms were treated in 29 of the 53 patients. Endovascular procedures were used for 16 patients (30%), surgery was performed in 1 patient (2%) and the two were combined in 12 (23%). In 23 of 53 cases (43%), unruptured aneurysms were left untreated, usually because of their small size. In 1 patient with unruptured aneurysms, the endovascular approach failed and the patient refused surgery.

Intracranial aneurysms: endovascular treatment with mechanical detachable spirals in 60 aneurysms

PURPOSE

To evaluate preliminary results with endovascular treatment (EVT) of intracranial aneurysms with mechanical detachable spirals.

MATERIALS AND METHODS

EVT with spirals was attempted in 57 patients with 60 aneurysms (47 berry, nine large, and four giant aneurysms). Thirty-seven patients had subarachnoid hemorrhage (three of whom were also treated for associated aneurysm), nine were asymptomatic, six had headache, three had mass effect, and two had neurologic deficits.

RESULTS

EVT with the spirals was achieved in 55 (92%) of the 60 aneurysms. Of 42 treated berry aneurysms and 13 treated large and giant aneurysms, 33 berry and nine large and giant aneurysms underwent 3-month angiographic follow-up. Complete occlusion was attained in 23 berry and four large and giant aneurysms, subtotal occlusion (doubtful or obvious small neck remnant) was obtained in eight berry and four large and giant aneurysms, and incomplete occlusion was obtained in two berry aneurysms and one giant aneurysm. These results were obtained after one procedure in 21 patients, after two procedures in 19 patients, and after three procedures in two patients. Seven patients had complications that necessitated infusion of urokinase. Permanent neurologic deficits were found in three. There were no deaths.

CONCLUSION

Good results were obtained with EVT of intracranial aneurysms with mechanical detachable spirals. These spirals are characterized by rapid detachment and low cost.

Endovascular treatment of anterior communicating artery aneurysms using Guglielmi detachable coils

The aim of this study was to evaluate endovascular treatment of anterior communicating artery aneurysms using Guglielmi detachable coils GDC. To obtain long-term follow-up, we selected patients treated between October 1992 and March 1994. Among the 251 berry aneurysms treated by detachable coils at our institution, 36 were located at the anterior communicating artery and treated with GDC. The most frequent clinical presentation in this group (86%) was subarachnoid haemorrhage (30 cases). There were 23 aneurysms which were completely and 6 were partially occluded. We did not treat 7 aneurysms. In 3 cases, no endovascular treatment was attempted either because the aneurysmal neck was not clearly distinct from the adjacent, or parent vessels (2 cases), or because the aneurysm sac was too small (1 case). In 4 cases, treatment failed because of atheroma of the cervical and intracranial vessels. Complications were, in the majority of cases, related to clotting (3 cases) with a good outcome in 2 cases and neurological sequelae in 1. In 1 case rupture of the aneurysm occurred during treatment. Endovascular packing was continued until complete occlusion of the aneurysm was achieved and no clinical complication was observed after the treatment. Two patients died as a result of complications of subarachnoid haemorrhage (vasospasm in one case, pulmonary complications in the other). Endovascular treatment using GDC is an efficient technique for treating anterior communicating artery aneurysms even in the acute phase of bleeding.

Selective occlusion of basilar artery aneurysms using controlled detachable coils: report of 35 cases

The development of new devices, especially controlled detachable coils, has made the endovascular approach one of the modalities for the treatment of intracranial aneurysms. We describe the treatment and present the results of 35 patients treated by selective occlusion of basilar artery aneurysms in our department during a period of 2 years (November 1992-November 1994). This period of time was chosen to analyze a homogeneous population treated since the introduction of controlled detachable coils and also to be able to have as many follow-up angiographic controls of the treated aneurysms as possible. The clinical presentation was subarachnoid hemorrhage in 32 patients and transient ischemic attack in 1 patient. In another two patients, the aneurysms were incidentally discovered. The majority of the aneurysms were berry aneurysms. The aneurysms were located at the basilar bifurcation (23 patients), at the basilar tip between the posterior cerebral artery and the superior cerebellar artery (5 patients), on the basilar trunk (3 patients), and at the vertebrobasilar junction (4 patients). Endovascular treatment using coils was achieved in 34 patients, using Guglielmi detachable coils (Target Therapeutics, San Jose, CA) in 29 patients and mechanical detachable spirals (Balt, Montmorency, France) in 5 patients. One patient died during the positioning of the first coil into the aneurysmal sac. Twenty-five of 35 aneurysms (73.5%) were completely occluded. Nine aneurysms (26.5%) were only partially (> 90%) occluded. No subsequent bleeding occurred during the follow-up period. Two patients treated in the acute phase of subarachnoid hemorrhage died days or weeks after endovascular treatment because of complications related to the natural history of subarachnoid hemorrhage (vasospasm in one patient and pulmonary complications in the other). In three patients, clotting occurred during the endovascular procedure. In all three patients, occlusion of the aneurysmal sac was achieved despite clotting. Urokinase was administered to two of the three patients. In the remaining patient, no fibrinolytic therapy was initiated. The clinical outcomes were excellent for all three patients. In this study, the morbidity-mortality rate of the endovascular technique is low (3%). If we include complications related to the subarachnoid bleeding, the morbidity-mortality rate remains low (8.8%) Regarding basilar artery aneurysms, endovascular treatment (selective occlusion by controlled detachable coils) is now useful for some patients, especially those with small aneurysms. However, long-term anatomic follow-up is needed to accurately evaluate the role of this treatment modality in the management of basilar aneurysms.

Endovascular treatment of pericallosal artery aneurysms

Recent technical developments have made endovascular treatment using controlled-detachable coils suitable for intracranial aneurysms. However, endovascular approach of the aneurysms of the pericallosal artery remains difficult because of their usual small size and their anatomical situation.

[Embolization by direct puncture of hypervascularized ORL tumors]

Direct intratumoral embolization was used to treat five patients with vascularized tumors of the head and neck: 2 nasopharyngeal angiofibroma, 2 glomus jugulare tumors and 1 hemangiopericytoma. Embolization was performed by direct puncture and intratumoral injection of a plastic mixture under angiographic control. In 4 patients, embolization was performed preoperatively. Devascularization was induced in at least 90% of the volume of these tumors, thus facilitating subsequent surgical removal of the tumor. In 1 patient, embolization was performed with palliative intent. Good regression of symptoms was obtained.