The Use of Infrared Thermography to Develop and Assess a Wearable Sock and Monitor Foot Temperature in Diabetic Subjects.

One important health problem that could affect diabetics is diabetic foot syndrome, as risk of ulceration, neuropathy, ischemia and infection. Unnoticed minor injuries, subsequent infection and ulceration may end in a foot amputation. Preliminary studies have shown a relationship between increased skin temperature and asymmetries between the same regions of both feet. In the preulceration phase, to develop a smart device able to control the temperature of these types of patients to avoid this risk might be very useful. A statistical analysis has been carried out with a sample of foot temperature data obtained from 93 individuals, of whom 44 are diabetics and 49 nondiabetics and among them 43% are men and 57% are women. Data obtained with a thermographic camera has been successful in providing a set of regions of interest, where the temperature could influence the individual, and the behavior of several variables that could affect these subjects provides a mathematical model. Finally, an in-depth analysis of existing sensors situated in those positions, namely, heel, medial midfoot, first metatarsal head, fifth metatarsal head, and first toe has allowed for the development of a smart sock to store temperatures obtained every few minutes in a mobile device.

Intrathecal cell therapy with autologous stromal cells increases cerebral glucose metabolism and can offer a new approach to the treatment of Alzheimer's type dementia.

BACKGROUND AIMS: After recent observations that intrathecal administration of autologous bone marrow mesenchymal stromal cells (MSCs) increases cerebral metabolism in patients with severe traumatic brain injury (TBI), we examined this type of cell therapy in Alzheimer's type dementia. METHODS: Three patients with clinical diagnosis of Alzheimer's disease received every 3 months 100million autologous MSCs by intrathecal route, until a total dose of 300million. RESULTS: During cell therapy the patients showed arrest in neurological deterioration and two of them manifested clear improvement of previous symptoms. A global increase in cerebral glucose metabolism, measured using 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET), was observed after every administration of cell therapy. CONCLUSIONS: Our present findings suggest that intrathecal administrations of autologous MSCs can be a new strategy for the treatment of Alzheimer's dementia.

Review on Wearables to Monitor Foot Temperature in Diabetic Patients.

One of the diseases that could affect diabetic patients is the diabetic foot problem. Unnoticed minor injuries and subsequent infection can lead to ischemic ulceration, and may end in a foot amputation. Preliminary studies have shown that there is a positive relationship between increased skin temperature and the pre⁻ulceration phase. Hence, we have carried out a review on wearables, medical devices, and sensors used specifically for collecting vital data. In particular, we are interested in the measure of the foot⁻temperature. Since there is a large amount of this type of medical wearables, we will focus on those used to measure temperature and developed in Spain.

Intrathecal administration of autologous mesenchymal stromal cells for spinal cord injury: Safety and efficacy of the 100/3 guideline.

BACKGROUND AIMS: Cell therapy with autologous mesenchymal stromal cells (MSCs) in patients with spinal cord injury (SCI) is beginning, and the search for its better clinical application is an urgent need. METHODS: We present a phase 2 clinical trial in patients with chronic SCI who received three intrathecal administrations of 100 x 106 MSCs and were followed for 10 months from the first administration. Efficacy analysis was performed on nine patients, and safety analysis was performed on 11 patients. Clinical scales, urodynamic, neurophysiological and neuroimaging studies were performed previous to treatment and at the end of the follow-up. RESULTS: The treatment was well-tolerated, without any adverse event related to MSC administration. Patients showed variable clinical improvement in sensitivity, motor power, spasms, spasticity, neuropathic pain, sexual function or sphincter dysfunction, regardless of the level or degree of injury, age or time elapsed from the SCI. In the course of follow-up three patients, initially classified as ASIA A, B and C, changed to ASIA B, C and D, respectively. In urodynamic studies, at the end of follow-up, 66.6% of the patients showed decrease in postmicturition residue and improvement in bladder compliance. At this time, neurophysiological studies showed that 55.5% of patients improved in somatosensory or motor-evoked potentials, and that 44.4% of patients improved in voluntary muscle contraction together with infralesional active muscle reinnervation. CONCLUSIONS: The present guideline for cell therapy is safe and shows efficacy in patients with SCI, mainly in recovery of sphincter dysfunction, neuropathic pain and sensitivity.

Cell therapy with autologous mesenchymal stromal cells in post-traumatic syringomyelia.

BACKGROUND AIMS: Recently, clinical studies show that cell therapy with mesenchymal stromal cells (MSCs) improves the sequelae chronically established in paraplegic patients, being necessary to know which of them can obtain better benefit. METHODS: We present here a phase 2 clinical trial that includes six paraplegic patients with post-traumatic syringomyelia who received 300 million MSCs inside the syrinx and who were followed up for 6 months. Clinical scales, urodynamic, neurophysiological, magnetic resonance (MR) and studies of ano-rectal manometry were performed to assess possible improvements. RESULTS: In all the cases, MR at the end of the study showed a clear reduction of the syrinx, and, at this time, signs of improvement in the urodynamic studies were found. Moreover, four patients improved in ano-rectal manometry. Four patients improved in neurophysiological studies, with signs of improvement in evoked potentials in three patients. In the American Spinal Injury Association (ASIA) assessment, only two patients improved in sensitivity, but clinical improvement in neurogenic bowel dysfunction was observed in four patients and three patients described improvement in bladder dysfunction. Spasms reduced in two of the five patients who had them previous to cell therapy, and spasticity was improved in the other two patients. Three patients had neuropathic pain before treatment, and it was reduced or disappeared completely during the study. Only two adverse events ocurred, without relation to the cell therapy. CONCLUSIONS: Cell therapy can be considered as a new alternative to the treatment of post-traumatic syringomyelia, achieving reduction of syrinx and clinical improvements in individual patients.

Progressive increase in brain glucose metabolism after intrathecal administration of autologous mesenchymal stromal cells in patients with diffuse axonal injury.

BACKGROUND AIMS: Cell therapy in neurological disability after traumatic brain injury (TBI) is in its initial clinical stage. We describe our preliminary clinical experience with three patients with diffuse axonal injury (DAI) who were treated with intrathecal administration of autologous mesenchymal stromal cells (MSCs). METHODS: Three patients with established neurological sequelae due to DAI received intrathecally autologous MSCs. The total number of MSCs administered was 60 × 106 (one patient), 100 × 106 (one patient) and 300 × 106 (one patient). RESULTS: All three patients showed improvement after cell therapy, and subsequent studies with 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) showed a diffuse and progressive increase in brain glucose metabolism. CONCLUSION: Our present results suggest benefit of intrathecal administration of MSCs in patients with DAI, as well as a relationship between this type of treatment and increase in brain glucose metabolism. These preliminary findings raise the question of convenience of assessing the potential benefit of intrathecal administration of MSCs for brain diseases in which a decrease in glucose metabolism represents a crucial pathophysiological finding, such as Alzheimer's disease (AD) and other dementias.

Repeated subarachnoid administrations of autologous mesenchymal stromal cells supported in autologous plasma improve quality of life in patients suffering incomplete spinal cord injury.

BACKGROUND AIMS: Cell therapy with mesenchymal stromal cells (MSCs) offers new hope for patients suffering from spinal cord injury (SCI). METHODS: Ten patients with established incomplete SCI received four subarachnoid administrations of 30 × 106 autologous bone marrow MSCs, supported in autologous plasma, at months 1, 4, 7 and 10 of the study, and were followed until the month 12. Urodynamic, neurophysiological and neuroimaging studies were performed at months 6 and 12, and compared with basal studies. RESULTS: Variable improvement was found in the patients of the series. All of them showed some degree of improvement in sensitivity and motor function. Sexual function improved in two of the eight male patients. Neuropathic pain was present in four patients before treatment; it disappeared in two of them and decreased in another. Clear improvement in bladder and bowel control were found in all patients suffering previous dysfunction. Before treatment, seven patients suffered spasms, and two improved. Before cell therapy, nine patients suffered variable degree of spasticity, and 3 of them showed clear decrease at the end of follow-up. At this time, nine patients showed infra-lesional electromyographic recordings suggesting active muscle reinnervation, and eight patients showed improvement in bladder compliance. After three administrations of MSCs, mean values of brain-derived neurotrophic factor, glial-derived neurotrophic factor, ciliary neurotrophic factor, and neurotrophin 3 and 4 showed slight increases compared with basal levels, but without statistically significant difference. CONCLUSIONS: Administration of repeated doses of MSCs by subarachnoid route is a well-tolerated procedure that is able to achieve progressive and significant improvement in the quality of life of patients suffering incomplete SCI.

An approach to personalized cell therapy in chronic complete paraplegia: The Puerta de Hierro phase I/II clinical trial.

BACKGROUND AIMS: Cell transplantation in patients suffering spinal cord injury (SCI) is in its initial stages, but currently there is confusion about the results because of the disparity in the techniques used, the route of administration, and the criteria for selecting patients. METHODS: We conducted a clinical trial involving 12 patients with complete and chronic paraplegia (average time of chronicity, 13.86 years; SD, 9.36). The characteristics of SCI in magnetic resonance imaging (MRI) were evaluated for a personalized local administration of expanded autologous bone marrow mesenchymal stromal cells (MSCs) supported in autologous plasma, with the number of MSCs ranging from 100 × 10(6) to 230 × 10(6). An additional 30 × 10(6) MSCs were administered 3 months later by lumbar puncture into the subarachnoid space. Outcomes were evaluated at 3, 6, 9 and 12 months after surgery through clinical, urodynamic, neurophysiological and neuroimaging studies. RESULTS: Cell transplantation is a safe procedure. All patients experienced improvement, primarily in sensitivity and sphincter control. Infralesional motor activity, according to clinical and neurophysiological studies, was obtained by more than 50% of the patients. Decreases in spasms and spasticity, and improved sexual function were also common findings. Clinical improvement seems to be dose-dependent but was not influenced by the chronicity of the SCI. CONCLUSION: Personalized cell therapy with MSCs is safe and leads to clear improvements in clinical aspects and quality of life for patients with complete and chronically established paraplegia.

Dual Strategy With Oral Phosphodiesterase Type 5 Inhibition and Intracavernosal Implantation of Mesenchymal Stem Cells Is Superior to Individual Approaches in the Recovery of Erectile and Cavernosal Functions After Cavernous Nerve Injury in Rats.

INTRODUCTION: Novel effective therapeutic strategies are necessary for treating erectile dysfunction secondary to cavernous nerve injury (CNI). AIM: To functionally evaluate the benefits of long-term oral treatment with a phosphodiesterase type 5 inhibitor on the potential capacity of intracavernosal cell therapy to recover erectile function after CNI. METHODS: Bilateral crush CNI (BCNI) was produced in anesthetized male rats. After BCNI, rats were treated with the phosphodiesterase type 5 inhibitor tadalafil (TAD; 5 mg/kg/d orally; BCNI + TAD), a single intracavernosal injection of bone marrow-derived mesenchymal stem cells (BMSCs; BCNI + BMSC), or dual therapy (BCNI + BMSC + TAD). Ex vivo function of the corpus cavernosum (CC) and in vivo intracavernosal pressure responses to CN electrical stimulation were evaluated 4 weeks after BCNI. Trichrome staining and terminal 2'-deoxyuridine-5'-triphosphate nick-end labeling assay were used for fibrosis and apoptosis determination, respectively, in the CC. MAIN OUTCOME MEASURES: In vivo erectile responses in anesthetized rats, ex vivo evaluation of endothelium-dependent relaxation, neurogenic relaxation and neurogenic contraction in CC strips, and histologic evaluation of fibrosis and apoptosis in cavernosal tissue. RESULTS: BCNI resulted in a marked decrease of erectile responses that were partly recovered in the BCNI + TAD and BCNI + BMSC groups. Complete recovery of erectile function was achieved only in the BCNI + BMSC + TAD group. Endothelium-dependent and nitric oxide donor-induced relaxations of the CC were not altered by BCNI or the treatments. BCNI resulted in enhanced neurogenic adrenergic contractions and impaired nitrergic relaxations of the CC. The BCNI + TAD group displayed diminished neurogenic contractions, whereas the BCNI + TAD and BCNI + BMSC groups showed partly recovered nitrergic responses. In the BCNI + BMSC + TAD group, neurogenic contractions were decreased and nitrergic relaxations were normalized. Cavernosal apoptosis and fibrosis were similarly prevented in the BCNI + TAD, BCNI + BMSC, and BCNI + BMSC + TAD groups. CONCLUSION: A dual strategy combining the intracavernosal injection of BMSCs and oral administration of TAD was superior to individual approaches in normalizing neurogenic control of cavernosal tone and preserving erectile function after CNI, suggesting the potential of this dual strategy in the future management of erectile dysfunction after radical prostatectomy.

Is the subarachnoid administration of mesenchymal stromal cells a useful strategy to treat chronic brain damage?

BACKGROUND AIMS: Traumatic brain injury (TBI) is a leading cause of mortality and morbidity worldwide. Developing effective protocols for the administration of mesenchymal stromal cells (MSCs) is a promising therapeutic strategy to treat TBI. It is important to develop alternatives to direct parenchymal injection at the injury site because direct injection is an expensive and invasive technique. Subarachnoid transplantation, a minimally invasive and low-risk procedure, may be an important and clinically applicable strategy. The aim of this study was to test the therapeutic effect of subarachnoid administration of MSCs on functional outcome 2 months after an experimental TBI in rats. METHODS: Two months after TBI, 30 female Wistar rats were divided into 3 groups (n = 10 in each group): sham, MSC (received 2 × 10(6) MSCs) and saline (received only saline) groups. Neurological function, brain and spinal cords samples and cerebrospinal fluid were studied. RESULTS: No significant differences were found in neurological evaluation and after histological analysis; differences in the expression of neurotrophins were present but were not statistically significant. MSCs survived in the host tissue, and some expressed neural markers. CONCLUSIONS: Similar to direct parenchymal injections, transplanted MSCs survive, migrate to the injury cavity and differentiate into mature neural cell types for at least 6 months after engraftment. These results open the possibility that MSC administration through subarachnoid administration may be a treatment for the consequences of TBI. The transplantation technique and cell number should be adjusted to obtain functional outcome and neurotrophin production differences.

Perilesional intrathecal administration of autologous bone marrow stromal cells achieves functional improvement in pigs with chronic paraplegia.

BACKGROUND AIMS: At present, on the basis of the great number of preclinical studies and preliminary clinical trials in humans, bone marrow stromal cell (BMSC) transplantation offers promise in the treatment of paraplegia. Nevertheless, there is not enough experience in humans about the best candidates for this type of cell therapy or details about the best parameters or best route of administration. METHODS: Two adult paraplegic pigs with chronic paraplegia were treated only with perilesional intrathecal administration of 40 × 10(6) autologous BMSC suspended in autologous plasma and followed for 1 year after cell transplantation. RESULTS: Our study showed clinical improvement, starting at 2 mo after BMSC administration and reaching stabilization at 10 mo. This was associated with recovery of previously abolished somatosensory-evoked potentials. At the end of the study, histological images suggested spinal cord regeneration. CONCLUSIONS: Our present findings suggest the possible utility of perilesional intrathecal administration of autologous BMSC in patients with chronic paraplegia.

Cell therapy with bone marrow stromal cells after intracerebral hemorrhage: impact of platelet-rich plasma scaffolds.

BACKGROUND AIMS: Cell therapy using bone marrow stromal cells (BMSCs) has been considered a promising strategy for neurologic sequelae after intracerebral hemorrhage (ICH). However, after intracerebral administration of BMSCs, most of the cells die, partly because of the absence of extracellular matrix. Intracerebral transplantation of BMSCs, supported in a platelet-rich plasma (PRP) scaffold, optimizes this type of cell therapy. METHODS: ICH was induced by stereotactic injection of 0.5 IU of collagenase type IV in the striatum of adult Wistar rats (n = 40). Two months later, the rats were subjected to intracerebral administration of 5 × 10(6) allogeneic BMSCs embedded in a PRP scaffold (n = 10), 5 × 10(6) allogeneic BMSCs in saline (n = 10), PRP-derived scaffold only (n = 10) or saline only (n = 10). Functional improvements in each group over the next 6 months were assessed using Rotarod and Video-Tracking-Box tests. Endogenous neurogenesis and survival of transplanted BMSCs were examined at the end of follow-up. RESULTS: Our study demonstrated neurologic improvement after BMSC transplantation and significantly better functional improvement for the group of animals that received BMSCs in the PRP-derived scaffold compared with the group that received BMSCs in saline. Histologic results showed that better functional outcome was associated with strong activation of endogenous neurogenesis. After intracerebral administration of BMSCs, donor cells were integrated in the injured tissue and showed phenotypic expression of glial fibrillary acidic protein and neuronal nucleus. CONCLUSIONS: PRP-derived scaffolds increase the viability and biologic activity of BMSCs and optimize functional recovery when this type of cell therapy is applied after ICH.

Cell transplantation in paraplegic patients: the importance of properly assessing the spinal cord morphology.

INTRODUCTION: Cell transplantation in paraplegic patients is beginning, but scarce attention is paid to the morphology of lesions. MATERIAL AND METHODS: We studied using magnetic resonance imaging (MRI) the morphology of the injured spinal cord in 200 patients with chronic and complete paraplegia after spinal cord injury (SCI) at the thoracic level. RESULTS: When it was possible to undertake a correct study of the lesion, approximately 35% of patients had images showing spinal cord transection or showed fine tracts of tissue that connected both edges of a virtually transected spinal cord. Approximately 30% of patients had significant kyphosis with chronic spinal cord compression, and approximately 5% of cases had extensive spinal cord atrophy. In only approximately 30% of the patients, MRI revealed a centromedullary cavity, which was generally limited to the level of the vertebral fracture, and failed to show any apparent spinal cord transection. CONCLUSIONS: Humans suffering from chronically established paraplegia show a great variability of lesions, which differs from the standardized images of SCI obtained in animal models. When we design clinical trials, our goal should be to achieve a correct selection of patients, and the morphology of the spinal cord must be one of the main factors to consider.

Allogeneic bone marrow stromal cell transplantation after cerebral hemorrhage achieves cell transdifferentiation and modulates endogenous neurogenesis.

BACKGROUND AIMS: When a severe neurologic lesion occurs as a consequence of intracerebral hemorrhage (ICH), there is no effective treatment available for improving the outcome. However, cell therapy has opened new perspectives on reducing neurologic sequels subsequent to this disease. METHODS: In this study, ICH was induced by stereotactic injection of 0.5 U collagenase type IV in the striatum of adult Wistar rats, and 2 h later a group of animals (n = 48) was subjected to intracerebral injection of 2 × 10(6) allogeneic bone marrow stromal cells (BMSC), while a control group (n = 48) received saline only. Eight animals from each group were killed at 48 h, 72 h, 7 days, 14 days, 21 days and 28 days. At these time-points, endogenous neurogenesis and survival of transplanted BMSC were studied. RESULTS: Our findings show that after allogeneic BMSC transplantation, donor cells can survive in the brain tissue expressing neuronal and astroglial markers. Furthermore, BMSC transplantation enhances endogenous neurogenesis and inhibits apoptosis of newborn neural cells. CONCLUSIONS: Although these results should be extrapolated to human disease with caution, it is obvious that cell therapy using allogeneic BMSC transplantation offers great promise for developing novel and efficacious strategies in patients suffering ICH.

Spontaneous resolution of syrinx: report of two cases in adults with Chiari malformation.

Idiopathic syringomyelia is a disease with variable clinical course. We report here two cases of spontaneous resolution of cervical syrinx in adults previously diagnosed of Chiari-syringomyelia complex. They are added to the nine cases previously reported, and documented the need for careful surgical indication in this disease based on the radiological images of spinal cord cavitation.

[Perspectives of cell therapy in sequelae from cerebrovascular accidents]. / Perspectivas de la terapia celular en las secuelas del accidente cerebrovascular hemorrágico.

INTRODUCTION: Spontaneous intracerebral hemorrhage (ICH) is associated with mortality between 40 and 50% of cases. Among the survivors, only 10% are independent after one month, there is no effective treatment of sequelae, except for the limited possibilities providing for rehabilitation. OBJECTIVES: We review the current experience with intracerebral transplantation of mesenchymal stem cells (MSCs) obtained from bone marrow as a potential treatment of neurological sequelae occurring after experimental ICH. MATERIAL AND METHODS: We describe the model of ICH by intracerebral administration of collagenaseIV at basal ganglia level in Wistar rats. Neurological deficits caused by ICH can be quantified through a variety of functional assessment test (NMSS, Rota-rod, VTB-test). 5×10allogeneic MSCs in 10µl of saline were administered intracerebrally in 10 animals, 2 months after ICH. In another 10 animals (controls) the same volume of saline was administered. Changes in the functional deficits were assessed during the next 6 months in both experimental groups. RESULTS: The results suggested therapeutic efficacy of MSCs transplantation and showed that transplanted stem cells can survive in the injured brain, transforming into neurons and glial cells. This form of cell therapy induces reactivation of endogenous neurogenesis at the subventricular zone (SVZ) and achieves antiapoptotic protective effect in the injured brain. CONCLUSIONS: Cell therapy represents an important field of research with potential clinical application to treatment of neurological sequels, currently considered irreversible. Neurosurgeons should become involved in the development of these new techniques that are likely to shape the future of this specialty.

Late transplantation of allogeneic bone marrow stromal cells improves neurologic deficits subsequent to intracerebral hemorrhage.

BACKGROUND AIMS: Stem cell therapy seems to be a promising therapeutic tool for treating central nervous system (CNS) injuries. Bone marrow stromal cell (BMSC) transplantation influences functional outcome subsequent to intracerebral hemorrhage (ICH), and enhances endogenous neurogenesis in acute condition studies. We investigated whether late administration of BMSC improves functional deficits subsequent to ICH. METHODS: Experimental ICH was induced by stereotactic injection of 0.5 IU collagenase type IV in the striatum of adult female Wistar rats, and 2 months later intralesional administration of 5 × 10(6) allogeneic BMSC from male donors rats in saline (n = 10), or saline only (n = 10), was performed. In the following 6 months, functional outcome was evaluated in each animal by rotarod, modified neurologic severity score (mNSS) and video-tracking box (VTB) tests. To study the behavior of BMSC after transplantation, in situ hybridization studies were performed, with double labeling of the chromosome Y-linked SrY-gene, and neuronal nuclei (NeuN) protein or gliofibrillary acidic protein (GFAP). RESULTS: The assessment test revealed significant improvements in functional outcome for the BMSC-treated animals after 2 months of follow-up. Histologic results showed that functional outcome was associated with strong reactivation of endogenous neurogenesis. Furthermore, intralesional BMSC not only integrated in the injured tissue but also showed phenotypic expression of GFAP and NeuN. CONCLUSIONS: Late intracerebral transplantation of allogeneic BMSC induces functional recovery after ICH. The possibility of using this type of cell therapy to reverse the consequences of hemorrhagic stroke in humans should be considered.

Cell therapy for spinal cord repair: optimization of biologic scaffolds for survival and neural differentiation of human bone marrow stromal cells.

BACKGROUND AIMS: The suppression of cell apoptosis using a biodegradable scaffold to replace the missing or altered extracellular matrix (ECM) could increase the survival of transplanted cells and thus increase the effectiveness of cell therapy. METHODS: We studied the best conditions for the proliferation and differentiation of human bone marrow stromal cells (hBMSC) when cultured on different biologic scaffolds derived from fibrin and blood plasma, and analyzed the best concentrations of fibrinogen, thrombin and calcium chloride for favoring cell survival. The induction of neural differentiation of hBMSC was done by adding to these scaffolds different growth factors, such as nerve growth factor (NGF), brain-derived-neurotrophic factor (BDNF) and retinoic acid (RA), at concentrations of 100 ng/mL (NGF and BDNF) and 1 micro/mL (RA), over 7 days. RESULTS: Although both types of scaffold allowed survival and neural differentiation of hBMSC, the results showed a clear superiority of platelet-rich plasma (PRP) scaffolds, mainly after BDNF administration, allowing most of the hBMSC to survive and differentiate into a neural phenotype. CONCLUSIONS: Given that clinical trials for spinal cord injury using hBMSC are starting, these findings may have important clinical applications.

Experimental rat model of chronic cerebral hypoperfusion-reperfusion mimicking normal perfusion pressure breakthrough phenomenon.

BACKGROUND: Normal perfusion pressure breakthrough (NPPB) phenomenon is a major life-threatening complication that restricts the treatment of complex intracranial arteriovenous malformations. The aim of the study it to develop a rat model mimicking NPPB phenomenon that enables the evaluation of any therapy to prevent such complication. METHODS: Twenty Wistar male rats were randomly assigned to either a study or a control group. Study animals underwent an end-to-side left external jugular vein-common carotid artery anastomosis and ligation of bilateral external carotid arteries. Control animals only underwent ligation of bilateral external carotid arteries. All animals were sacrificed sixty days after the procedure. Hemodynamic parameters [mean arterial pressure (MAP), intracranial pressure (ICP) and cerebral perfusion pressure (CPP)], blood-brain barrier (BBB) permeability (measured by fluorescein staining) and histological features were then compared between both groups. RESULTS: A significant decrease in MAP and CPP was confirmed in the study group. An increase in ICP was also observed. A significant decrease in MAP and CPP was also present in the study group when comparing preoperative values with those recorded on days 0 (postoperative), 7 and 60. Fluorescein staining findings were consistent with signs of BBB disruption in study animals. Histological analysis demonstrated an increased number of pyknotic neurons in the ipsilateral hemisphere of rat brains included in the study group. CONCLUSION: These results confirm that this model mimics a vascular steal state with chronic cerebral hypoperfusion comparable to patients with AVMs behavior and disruption of the BBB after fistula closure comparable to NPPB phenomenon disorders.