Search

Neurodevelopmental disorders (NDD) are characterized by neurocognitive involvement and life-limiting disabilities with classification primarily based on behavior and social symptoms, overlooking their neurobiology. This symptom-defined nosology results in clinical heterogeneity, complicates disease management, and leads to ineffective treatment development. This calls for a revolution in NDD classification towards one that considers the neurobiological mechanisms underlying behavior. This thesis investigates the role of altered neuronal oscillations due to imbalances in excitatory and inhibitory activity (E/I) as a neurophysiological framework in NDD. A balance between excitation and inhibition (E/I) is necessary for neuronal network organization, information processing, and cognitive integration. E/I imbalances are increasingly considered a pathophysiological mechanism in NDD. We propose a neurophysiology-based approach incorporating EEG measures sensitive to E/I changes to uncover a network dysfunction linked to individual behavioral profiles. This may enable physiological stratification within NDD and serve as a target to trial novel E/I-modulating therapies. Clinical estimations of neuronal network E/I ratios were lacking, so this project initially developed a method to quantify a functional measure of network-level E/I ratio (fE/I) using EEG (Chapter 1). Next, we tested the hypothesis that E/I imbalances characterize autism spectrum disorder (ASD). Initial findings revealed that individuals with ASD show a broader distribution of neuronal E/I ratios compared to healthy individuals, with variability linked to qualitative EEG abnormalities. This highlighted an unrecognized physiological heterogeneity within ASD that may influence symptomatology and treatment response. Further investigation using the EU-AIMS EEG dataset confirmed an association between network-level E/I, qualitative EEG abnormalities, and clinical symptoms in ASD (Chapter 2). These results suggest

INTRODUCTION: Bumetanide, a loop diuretic, was identified as a candidate drug for repurposing for Alzheimers disease (AD) based on its effects on transcriptomic apolipoprotein E signatures. Cross-sectional analyses of electronic health records suggest that bumetanide is associated with decreased prevalence of AD; however, temporality between bumetanide exposure and AD development has not been established. METHODS: We evaluated Medicare claims data using Cox proportional hazards regression to evaluate the association between time-dependent use of bumetanide and time to first AD diagnosis while controlling for patient characteristics. Multiple sensitivity analyses were conducted to test the robustness of the findings. RESULTS: We sampled 833,561 Medicare beneficiaries, 60.8% female, with mean (standard deviation) age of 70.4 (12). Bumetanide use was not significantly associated with AD risk (hazard ratio 1.05; 95% confidence interval, 0.99-1.10). DISCUSSION: Using a nationwide dataset and a retrospective cohort study design, we were not able to identify a time-dependent effect of bumetanide lowering AD risk. HIGHLIGHTS: Bumetanide was identified as a candidate for repurposing for Alzheimers disease (AD). We evaluated the association between bumetanide use and risk of AD. We used Medicare data and accounted for duration of bumetanide use. Bumetanide use was not significantly associated with risk of AD.

BackgroundExaggerated responses to sensory stimuli, a hallmark of Fragile X syndrome (FXS), contribute to anxiety and learning challenges. Sensory hypersensitivity is recapitulated in the Fmr1 knockout (KO) mouse model of FXS. Recent studies in Fmr1 KO mice have demonstrated differences in activity of cortical interneurons and a delayed switch in the polarity of GABA signaling during development. Previously, we reported that blocking the chloride transporter NKCC1 with the diuretic bumetanide, could rescue synaptic circuit phenotypes in primary somatosensory cortex (S1) of Fmr1 KO mice. However, it remains unknown whether bumetanide can rescue earlier circuit phenotypes or sensory hypersensitivity in Fmr1 KO mice.MethodsWe used acute and chronic systemic administration of bumetanide in Fmr1 KO mice and performed in vivo 2-photon calcium imaging to record neuronal activity, while tracking mouse behavior with high-resolution videos.ResultsWe demonstrate that layer (L) 2/3 pyramidal neurons in S1 of Fmr1 KO mice show a higher frequency of synchronous events at postnatal day (P) 6 compared to wild-type controls. This was reversed by acute administration of bumetanide. Furthermore, chronic bumetanide treatment (P5-P14) restored S1 circuit differences in Fmr1 KO mice, including reduced neuronal adaptation to repetitive whisker stimulation, and ameliorated tactile defensiveness. Bumetanide treatment also rectified the reduced feedforward inhibition of L2/3 neurons in S1 and boosted the circuit participation of parvalbumin interneurons.ConclusionsThis further supports the notion that synaptic, circuit, and sensory behavioral phenotypes in Fmr1 KO can be mitigated by inhibitors of NKCC1, such as the FDA-approved diuretic bumetanide.

BACKGROUND: A range of neurological pathologies may lead to secondary hydrocephalus. Treatment has largely been limited to surgical cerebrospinal fluid (CSF) diversion, as specific and efficient pharmacological options are lacking, partly due to the elusive molecular nature of the CSF secretion apparatus and its regulatory properties in physiology and pathophysiology.METHODS: CSF obtained from patients with subarachnoid hemorrhage (SAH) and rats with experimentally inflicted intraventricular hemorrhage (IVH) was analyzed for lysophosphatidic acid (LPA) by alpha-LISA. We employed the in vivo rat model to determine the effect of LPA on ventricular size and brain water content, and to reveal the effect of activation and inhibition of the transient receptor potential vanilloid 4 (TRPV4) ion channel on intracranial pressure and CSF secretion rate. LPA-mediated modulation of TRPV4 was determined with electrophysiology and an ex vivo radio-isotope assay was employed to determine the effect of these modulators on choroid plexus transport.RESULTS: Elevated levels of LPA were observed in CSF obtained from patients with subarachnoid hemorrhage (SAH) and from rats with experimentally-inflicted intraventricular hemorrhage (IVH). Intraventricular administration of LPA caused elevated brain water content and ventriculomegaly in experimental rats, via its action as an agonist of the choroidal transient receptor potential vanilloid 4 (TRPV4) channel. TRPV4 was revealed as a novel regulator of ICP in experimental rats via its ability to modulate the CSF secretion rate through its direct activation of the Na+/K+/2Cl- cotransporter (NKCC1) implicated in CSF secretion.CONCLUSIONS: Together, our data reveal that a serum lipid present in brain pathologies with hemorrhagic events promotes CSF hypersecretion and ensuing brain water accumulation via its direct action on TRPV4 and its downstream regulation of NKCC1. TRPV4 may therefore be a promising future pharmacolog

BACKGROUND: A range of neurological pathologies may lead to secondary hydrocephalus. Treatment has largely been limited to surgical cerebrospinal fluid (CSF) diversion, as specific and efficient pharmacological options are lacking, partly due to the elusive molecular nature of the CSF secretion apparatus and its regulatory properties in physiology and pathophysiology.METHODS: CSF obtained from patients with subarachnoid hemorrhage (SAH) and rats with experimentally inflicted intraventricular hemorrhage (IVH) was analyzed for lysophosphatidic acid (LPA) by alpha-LISA. We employed the in vivo rat model to determine the effect of LPA on ventricular size and brain water content, and to reveal the effect of activation and inhibition of the transient receptor potential vanilloid 4 (TRPV4) ion channel on intracranial pressure and CSF secretion rate. LPA-mediated modulation of TRPV4 was determined with electrophysiology and an ex vivo radio-isotope assay was employed to determine the effect of these modulators on choroid plexus transport.RESULTS: Elevated levels of LPA were observed in CSF obtained from patients with subarachnoid hemorrhage (SAH) and from rats with experimentally-inflicted intraventricular hemorrhage (IVH). Intraventricular administration of LPA caused elevated brain water content and ventriculomegaly in experimental rats, via its action as an agonist of the choroidal transient receptor potential vanilloid 4 (TRPV4) channel. TRPV4 was revealed as a novel regulator of ICP in experimental rats via its ability to modulate the CSF secretion rate through its direct activation of the Na+/K+/2Cl- cotransporter (NKCC1) implicated in CSF secretion.CONCLUSIONS: Together, our data reveal that a serum lipid present in brain pathologies with hemorrhagic events promotes CSF hypersecretion and ensuing brain water accumulation via its direct action on TRPV4 and its downstream regulation of NKCC1. TRPV4 may therefore be a promising future pharmacolog

BackgroundDiabetic ketoacidosis (DKA) causes brain injuries in children ranging from subtle to life-threatening. Previous studies suggest that DKA-related brain injury may involve both stimulation of Na-K-Cl cotransport and microglial activation. Other studies implicate the Na-K-Cl cotransporter and the Ca-activated K channel KCa3.1 in activation of microglia and ischemia-induced brain edema. In this study, we determined whether inhibiting cerebral Na-K-Cl cotransport or KCa3.1 could reduce microglial activation and decrease DKA-related inflammatory changes in the brain.MethodsUsing immunohistochemistry, we investigated cellular alterations in brain specimens from juvenile rats with DKA before, during and after insulin and saline treatment. We compared findings in rats treated with and without bumetanide (an inhibitor of Na-K-Cl cotransport) or the KCa3.1 inhibitor TRAM-34.ResultsGlial fibrillary acidic protein (GFAP) staining intensity was increased in the hippocampus during DKA, suggesting reactive astrogliosis. OX42 staining intensity was increased during DKA in the hippocampus, cortex and striatum, indicating microglial activation. Treatment with TRAM-34 decreased both OX42 and GFAP intensity suggesting a decreased inflammatory response to DKA. Treatment with bumetanide did not significantly alter OX42 or GFAP intensity.ConclusionsInhibiting KCa3.1 activity with TRAM-34 during DKA treatment decreases microglial activation and reduces reactive astrogliosis, suggesting a decreased inflammatory response.

BackgroundDiabetic ketoacidosis (DKA) causes brain injuries in children ranging from subtle to life-threatening. Previous studies suggest that DKA-related brain injury may involve both stimulation of Na-K-Cl cotransport and microglial activation. Other studies implicate the Na-K-Cl cotransporter and the Ca-activated K channel KCa3.1 in activation of microglia and ischemia-induced brain edema. In this study, we determined whether inhibiting cerebral Na-K-Cl cotransport or KCa3.1 could reduce microglial activation and decrease DKA-related inflammatory changes in the brain.MethodsUsing immunohistochemistry, we investigated cellular alterations in brain specimens from juvenile rats with DKA before, during and after insulin and saline treatment. We compared findings in rats treated with and without bumetanide (an inhibitor of Na-K-Cl cotransport) or the KCa3.1 inhibitor TRAM-34.ResultsGlial fibrillary acidic protein (GFAP) staining intensity was increased in the hippocampus during DKA, suggesting reactive astrogliosis. OX42 staining intensity was increased during DKA in the hippocampus, cortex and striatum, indicating microglial activation. Treatment with TRAM-34 decreased both OX42 and GFAP intensity suggesting a decreased inflammatory response to DKA. Treatment with bumetanide did not significantly alter OX42 or GFAP intensity.ConclusionsInhibiting KCa3.1 activity with TRAM-34 during DKA treatment decreases microglial activation and reduces reactive astrogliosis, suggesting a decreased inflammatory response.

Molecular cocrystals are of growing interest in pharmaceutics for their improved physicochemical properties. Their mechanochemical synthesis is very promising, being easy, cheap, and “green”. Here, for the first time, we report on cocrystallization of bumetanide, a diuretic and natriuretic active principle, and 4-aminobenzoic acid. The synthesis is performed both by wet and dry grinding. The cocrystal formation was investigated with a wide range of techniques, including solid- state NMR, IR, XRD, microscopy, and thermal analysis. Wet and dry grinding procedures led to different cocrystal polymorphs. In particular, the dry method gave a cocrystal by powder amorphization and subsequent crystallization. DFT calculations at the B3LYP/6-31+G(d,p) level of theory shed light on the H-bond scheme at the basis of cocrystal formation. The cocrystals showed improved solubility and dissolution rate with respect to the drug alone. This could guarantee a faster absorption and a better bioavailability of the active principle.

Background: The potency of intravenous bumetanide to furosemide using a ratio of 1:40 has been suggested; however, there are little data supporting this ratio. Recent drug shortages required the use of bumetanide in a large patient population, enabling further characterization of the efficacy of IV bumetanide. Objective: The primary objective of this study was to estimate a dose-response effect of IV bumetanide on urine output (UOP) in all patients that received 48 hours of therapy as well as in a subgroup of patients with heart failure (HF). This subgroup was used to compare the potency of bumetanide with furosemide. A secondary safety objective described electrolyte replacement required during therapy. Methods: This was a single-center retrospective study examining the dose-response effect of IV bumetanide in patients receiving at least 48 hours of intermittent (iIV) or continuous (cIV) dosing, measured by UOP per mg of drug received (mL/mg). The potency of IV bumetanide was compared with furosemide in a subset of patients with HF using pre-existing data. The safety of IV bumetanide was analyzed by quantifying electrolyte replacement received during the study period. Results: The primary outcome was higher in the iIV group (n=93) at 1273 ± 844 mL/mg compared with the cIV group (n=16) at 749 ± 370 mL/mg (P=0.002). Among patients with HF who received furosemide (iIV n=30, cIV n=26) or bumetanide (iIV n=30, cIV n=3), a potency ratio of 41:1 was found for the iIV group and 34:1 for all patients with HF. There was no significant difference in electrolyte replacement between groups. Conclusion: A greater response was seen with intermittent bumetanide compared with continuous infusion bumetanide. This study supports the 40:1 dose equivalence ratio (furosemide:bumetanide) in patients with HF receiving at least 48 hours of intravenous intermittent bumetanide., Antecedentes: Se ha sugerido que existe un ratio de potencia de la bumetanida con la furosemida de 1:40; sin embargo, hay pocos estudios que soporten este ratio. Recientes desabastecimientos requirieron el uso de bumetanida en una población grande de pacientes, lo que permitió una caracterización extensiva de la eficacia de la bumetanida IV. Objetivo: El objetivo primario de este estudio fue estimar la respuesta dosis-efecto de la bumetanida IV en la diuresis en todos los pacientes que recibieron 48 horas de tratamiento, así como en el subgrupo de pacientes con fallo cardiaco. Este subgrupo fue utilizado para comparar la potencia de la bumetanida con la furosemida. Un objetivo secundario de seguridad describió el reemplazo de electrolitos necesario durante el tratamiento. Métodos: Este fue un estudio unicéntrico retrospectivo que examinó el la respuesta dosefecto de la bumetanida IV en pacientes que la recibieron al menos 48 horas intermitentemente (iIV) o continua (cIV), medida por la diuresis por mg de medicamento recibido (mL/mg). La potencia de la bumetanida IV se comparó en la furosemida en un subgrupo de pacientes con fallo cardiaco utilizando datos pre-existentes. La seguridad de la bumetanida IV se analizó cuantificando el reemplazo electrolítico recibido durante el periodo de estudio. Resultados: El resultado primario fue mayor en el grupo iIV (n=93) con 1273 (SD=844) mL/mg, que en el grupo cIV (n=16) con 749 (SD=370) mL/mg (p=0,002). Entre los pacientes con fallo cardiaco que recibieron furosemida (iIV n=30, cIV n=26) o bumetanida (iIV n=30, cIV n=3) se encontró un ratio de potencia de 41:1 para el grupo iIV y de 34:1 para todos los pacientes con fallo cardiaco. No hubo diferencia significativa en el reemplazo electrolítico entre ambos grupos. Conclusión: Se encontró una respuesta mayor con la bumetanida intermitente que con la bumetanida en perfusión continua. Este estudio apoya el ratio de dosis equivalente de 40:1 (furosemida:bumetanida) en pacientes co

Background: The potency of intravenous bumetanide to furosemide using a ratio of 1:40 has been suggested; however, there are little data supporting this ratio. Recent drug shortages required the use of bumetanide in a large patient population, enabling further characterization of the efficacy of IV bumetanide. Objective: The primary objective of this study was to estimate a dose-response effect of IV bumetanide on urine output (UOP) in all patients that received 48 hours of therapy as well as in a subgroup of patients with heart failure (HF). This subgroup was used to compare the potency of bumetanide with furosemide. A secondary safety objective described electrolyte replacement required during therapy. Methods: This was a single-center retrospective study examining the dose-response effect of IV bumetanide in patients receiving at least 48 hours of intermittent (iIV) or continuous (cIV) dosing, measured by UOP per mg of drug received (mL/mg). The potency of IV bumetanide was compared with furosemide in a subset of patients with HF using pre-existing data. The safety of IV bumetanide was analyzed by quantifying electrolyte replacement received during the study period. Results: The primary outcome was higher in the iIV group (n=93) at 1273 ± 844 mL/mg compared with the cIV group (n=16) at 749 ± 370 mL/mg (P=0.002). Among patients with HF who received furosemide (iIV n=30, cIV n=26) or bumetanide (iIV n=30, cIV n=3), a potency ratio of 41:1 was found for the iIV group and 34:1 for all patients with HF. There was no significant difference in electrolyte replacement between groups. Conclusion: A greater response was seen with intermittent bumetanide compared with continuous infusion bumetanide. This study supports the 40:1 dose equivalence ratio (furosemide:bumetanide) in patients with HF receiving at least 48 hours of intravenous intermittent bumetanide., Antecedentes: Se ha sugerido que existe un ratio de potencia de la bumetanida con la furosemida de 1:40; sin embargo, hay pocos estudios que soporten este ratio. Recientes desabastecimientos requirieron el uso de bumetanida en una población grande de pacientes, lo que permitió una caracterización extensiva de la eficacia de la bumetanida IV. Objetivo: El objetivo primario de este estudio fue estimar la respuesta dosis-efecto de la bumetanida IV en la diuresis en todos los pacientes que recibieron 48 horas de tratamiento, así como en el subgrupo de pacientes con fallo cardiaco. Este subgrupo fue utilizado para comparar la potencia de la bumetanida con la furosemida. Un objetivo secundario de seguridad describió el reemplazo de electrolitos necesario durante el tratamiento. Métodos: Este fue un estudio unicéntrico retrospectivo que examinó el la respuesta dosefecto de la bumetanida IV en pacientes que la recibieron al menos 48 horas intermitentemente (iIV) o continua (cIV), medida por la diuresis por mg de medicamento recibido (mL/mg). La potencia de la bumetanida IV se comparó en la furosemida en un subgrupo de pacientes con fallo cardiaco utilizando datos pre-existentes. La seguridad de la bumetanida IV se analizó cuantificando el reemplazo electrolítico recibido durante el periodo de estudio. Resultados: El resultado primario fue mayor en el grupo iIV (n=93) con 1273 (SD=844) mL/mg, que en el grupo cIV (n=16) con 749 (SD=370) mL/mg (p=0,002). Entre los pacientes con fallo cardiaco que recibieron furosemida (iIV n=30, cIV n=26) o bumetanida (iIV n=30, cIV n=3) se encontró un ratio de potencia de 41:1 para el grupo iIV y de 34:1 para todos los pacientes con fallo cardiaco. No hubo diferencia significativa en el reemplazo electrolítico entre ambos grupos. Conclusión: Se encontró una respuesta mayor con la bumetanida intermitente que con la bumetanida en perfusión continua. Este estudio apoya el ratio de dosis equivalente de 40:1 (furosemida:bumetanida) en pacientes co

A number of antiepileptic medications that modulate GABA(A) mediated synaptic transmission are anxiolytic. The loop diuretics furosemide (Lasix) and bumetanide (Bumex) are thought to have antiepileptic properties. These drugs also modulate GABA(A) mediated signalling through their antagonism of cation-chloride cotransporters. Given that loop diuretics may act as antiepileptic drugs that modulate GABAergic signalling, we sought to investigate whether they also mediate anxiolytic effects. Here we report the first investigation of the anxiolytic effects of these drugs in rat models of anxiety. Furosemide and bumetanide were tested in adult rats for their anxiolytic effects using four standard anxiety models: 1) contextual fear conditioning; 2) fear-potentiated startle; 3) elevated plus maze, and 4) open-field test. Furosemide and bumetanide significantly reduced conditioned anxiety in the contextual fear-conditioning and fear-potentiated startle models. At the tested doses, neither compound had significant anxiolytic effects on unconditioned anxiety in the elevated plus maze and open-field test models. These observations suggest that loop diuretics elicit significant anxiolytic effects in rat models of conditioned anxiety. Since loop diuretics are antagonists of the NKCC1 and KCC2 cotransporters, these results implicate the cation-chloride cotransport system as possible molecular mechanism involved in anxiety, and as novel pharmacological target for the development of anxiolytics. In view of these findings, and since furosemide and bumetanide are safe and well tolerated drugs, the clinical potential of loop diuretics for treating some types of anxiety disorders deserves further investigation.

A number of antiepileptic medications that modulate GABA(A) mediated synaptic transmission are anxiolytic. The loop diuretics furosemide (Lasix) and bumetanide (Bumex) are thought to have antiepileptic properties. These drugs also modulate GABA(A) mediated signalling through their antagonism of cation-chloride cotransporters. Given that loop diuretics may act as antiepileptic drugs that modulate GABAergic signalling, we sought to investigate whether they also mediate anxiolytic effects. Here we report the first investigation of the anxiolytic effects of these drugs in rat models of anxiety. Furosemide and bumetanide were tested in adult rats for their anxiolytic effects using four standard anxiety models: 1) contextual fear conditioning; 2) fear-potentiated startle; 3) elevated plus maze, and 4) open-field test. Furosemide and bumetanide significantly reduced conditioned anxiety in the contextual fear-conditioning and fear-potentiated startle models. At the tested doses, neither compound had significant anxiolytic effects on unconditioned anxiety in the elevated plus maze and open-field test models. These observations suggest that loop diuretics elicit significant anxiolytic effects in rat models of conditioned anxiety. Since loop diuretics are antagonists of the NKCC1 and KCC2 cotransporters, these results implicate the cation-chloride cotransport system as possible molecular mechanism involved in anxiety, and as novel pharmacological target for the development of anxiolytics. In view of these findings, and since furosemide and bumetanide are safe and well tolerated drugs, the clinical potential of loop diuretics for treating some types of anxiety disorders deserves further investigation.

ObjectiveCerebral edema is a life-threatening complication of diabetic ketoacidosis (DKA) in children. Recent data suggest that cerebral hypoperfusion and activation of cerebral ion transporters may be involved, but data describing cerebral metabolic alterations during DKA are lacking.Research design and methodsWe evaluated 50 juvenile rats with DKA and 21 normal control rats using proton and phosphorus magnetic resonance spectroscopy (MRS). MRS measured cerebral intracellular pH and ratios of metabolites including ATP/inorganic phosphate (Pi), phosphocreatine (PCr)/Pi, N-acetyl aspartate (NAA)/creatine (Cr), and lactate/Cr before and during DKA treatment. We determined the effects of treatment with insulin and intravenous saline with or without bumetanide, an inhibitor of Na-K-2Cl cotransport, using ANCOVA with a 2 x 2 factorial study design.ResultsCerebral intracellular pH was decreased during DKA compared with control (mean +/- SE difference -0.13 +/- 0.03; P < 0.001), and lactate/Cr was elevated (0.09 +/- 0.02; P < 0.001). DKA rats had lower ATP/Pi and NAA/Cr (-0.32 +/- 0.10, P = 0.003, and -0.14 +/- 0.04, P < 0.001, respectively) compared with controls, but PCr/Pi was not significantly decreased. During 2-h treatment with insulin/saline, ATP/Pi, PCr/Pi, and NAA/Cr declined significantly despite an increase in intracellular pH. Bumetanide treatment increased ATP/Pi and PCr/Pi and ameliorated the declines in these values with insulin/saline treatment.ConclusionsThese data demonstrate that cerebral metabolism is significantly compromised during DKA and that further deterioration occurs during early DKA treatment--consistent with possible effects of cerebral hypoperfusion and reperfusion injury. Treatment with bumetanide may help diminish the adverse effects of initial treatment with insulin/saline.

ObjectiveCerebral edema is a life-threatening complication of diabetic ketoacidosis (DKA) in children. Recent data suggest that cerebral hypoperfusion and activation of cerebral ion transporters may be involved, but data describing cerebral metabolic alterations during DKA are lacking.Research design and methodsWe evaluated 50 juvenile rats with DKA and 21 normal control rats using proton and phosphorus magnetic resonance spectroscopy (MRS). MRS measured cerebral intracellular pH and ratios of metabolites including ATP/inorganic phosphate (Pi), phosphocreatine (PCr)/Pi, N-acetyl aspartate (NAA)/creatine (Cr), and lactate/Cr before and during DKA treatment. We determined the effects of treatment with insulin and intravenous saline with or without bumetanide, an inhibitor of Na-K-2Cl cotransport, using ANCOVA with a 2 x 2 factorial study design.ResultsCerebral intracellular pH was decreased during DKA compared with control (mean +/- SE difference -0.13 +/- 0.03; P < 0.001), and lactate/Cr was elevated (0.09 +/- 0.02; P < 0.001). DKA rats had lower ATP/Pi and NAA/Cr (-0.32 +/- 0.10, P = 0.003, and -0.14 +/- 0.04, P < 0.001, respectively) compared with controls, but PCr/Pi was not significantly decreased. During 2-h treatment with insulin/saline, ATP/Pi, PCr/Pi, and NAA/Cr declined significantly despite an increase in intracellular pH. Bumetanide treatment increased ATP/Pi and PCr/Pi and ameliorated the declines in these values with insulin/saline treatment.ConclusionsThese data demonstrate that cerebral metabolism is significantly compromised during DKA and that further deterioration occurs during early DKA treatment--consistent with possible effects of cerebral hypoperfusion and reperfusion injury. Treatment with bumetanide may help diminish the adverse effects of initial treatment with insulin/saline.

ObjectiveCerebral edema (CE) is a potentially life-threatening complication of diabetic ketoacidosis (DKA) in children. Osmotic fluctuations during DKA treatment have been considered responsible, but recent data instead suggest that cerebral hypoperfusion may be involved and that activation of cerebral ion transporters may occur. Diminished cerebral blood flow (CBF) during DKA, however, has not been previously demonstrated. We investigated CBF and edema formation in a rat model of DKA and determined the effects of bumetanide, an inhibitor of Na-K-Cl cotransport.Research design and methodsJuvenile rats with streptozotocin-induced DKA were treated with intravenous saline and insulin, similar to human treatment protocols. CBF was determined by magnetic resonance (MR) perfusion-weighted imaging before and during treatment, and CE was assessed by determining apparent diffusion coefficients (ADCs) using MR diffusion-weighted imaging.ResultsCBF was significantly reduced in DKA and was responsive to alterations in pCO(2). ADC values were reduced, consistent with cell swelling. The reduction in ADCs correlated with dehydration, as reflected in blood urea nitrogen concentrations. Bumetanide caused a rapid rise in ADCs of DKA rats without significantly changing CBF, while saline/insulin caused a rapid rise in CBF and a gradual rise in ADCs. DKA rats treated with bumetanide plus saline/insulin showed a trend toward more rapid rise in cortical ADCs and a larger rise in striatal CBF than those observed with saline/insulin alone.ConclusionsThese data demonstrate that CE in DKA is accompanied by cerebral hypoperfusion before treatment and suggest that blocking Na-K-Cl cotransport may reduce cerebral cell swelling.

ObjectiveCerebral edema (CE) is a potentially life-threatening complication of diabetic ketoacidosis (DKA) in children. Osmotic fluctuations during DKA treatment have been considered responsible, but recent data instead suggest that cerebral hypoperfusion may be involved and that activation of cerebral ion transporters may occur. Diminished cerebral blood flow (CBF) during DKA, however, has not been previously demonstrated. We investigated CBF and edema formation in a rat model of DKA and determined the effects of bumetanide, an inhibitor of Na-K-Cl cotransport.Research design and methodsJuvenile rats with streptozotocin-induced DKA were treated with intravenous saline and insulin, similar to human treatment protocols. CBF was determined by magnetic resonance (MR) perfusion-weighted imaging before and during treatment, and CE was assessed by determining apparent diffusion coefficients (ADCs) using MR diffusion-weighted imaging.ResultsCBF was significantly reduced in DKA and was responsive to alterations in pCO(2). ADC values were reduced, consistent with cell swelling. The reduction in ADCs correlated with dehydration, as reflected in blood urea nitrogen concentrations. Bumetanide caused a rapid rise in ADCs of DKA rats without significantly changing CBF, while saline/insulin caused a rapid rise in CBF and a gradual rise in ADCs. DKA rats treated with bumetanide plus saline/insulin showed a trend toward more rapid rise in cortical ADCs and a larger rise in striatal CBF than those observed with saline/insulin alone.ConclusionsThese data demonstrate that CE in DKA is accompanied by cerebral hypoperfusion before treatment and suggest that blocking Na-K-Cl cotransport may reduce cerebral cell swelling.

In the context of the "pump-leak" hypothesis (37), changes in myocardial intracellular Na (Nai) during ischemia and reperfusion have historically been interpreted to be the result of changes in Na efflux via the Na-K pump. We investigated the alternative hypothesis that changes in Nai during ischemia are the result of changes in the Na "leak" rather than changes in the pump. More specifically, we hypothesize that the increase in Nai during ischemia is in part the result of increased Na uptake mediated by Na/H exchange. Furthermore, we present data consistent with the interpretation that the Na-K-2Cl cotransporter is active (or, alternatively, displaced from equilibrium) during ischemia and may contribute an additional Na efflux pathway during reperfusion. Thus inhibition of Na efflux via Na-K-2Cl cotransport during ischemia and reperfusion could result in increased Nai and therefore decreased force driving Ca efflux via Na/Ca exchange and ultimately increased intracellular Ca concentration ([Ca]i). Nai (in meq/kg dry wt) and [Ca]i (in nM) were measured in isolated Langendorff-perfused rabbit hearts using nuclear magnetic resonance spectroscopy. Except, during the 65 min of ischemia, hearts were perfused with N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid-buffered Krebs-Henseleit solution equilibrated with 100% O2 at 23 degrees C and pH 7.4 +/- 0.05. During ischemia, Nai rose from 16.6 +/- 0.3 to 62.9 +/- 5.1 (delta Nai approximately 46) meq/kg dry wt and decreased during subsequent reperfusion (mean +/- SE, n = 3 hearts). To measure Na uptake ("leak") in the absence of efflux via the Na-K pump, in all of the protocols described below, the perfusate was nominally K-free solution containing 1 mM ouabain for 10 min before ischemia and during the 30-min reperfusion. After K-free perfusion, Nai rose from 20.2 +/- 0.5 to 79.1 +/- 5.3 (delta Nai approximately 59) meq/kg dry wt (n = 3) during ischemia and decreased during K-free reperfusion. When amiloride (1 mM) was a

A series of compounds related to torasemide, a loop diuretic, were synthesized and examined for their diuretic potency and inhibitory activity on the erythrocyte and renal medullary thick ascending limb vesicle Na+,2Cl-,K+ cotransport in Milan hypertensive (MHS) and normotensive (MNS) rat strains, where previous studies had demonstrated an alteration of the cotransport system genetically related to hypertension. From the results of the screening, structure-activity relationships were drawn and two compounds, JDL 961 and C 2921 were selected. Their IC50 on renal vesicle cotransport were similar in the two strains (JDL 961: MHS = 1.8 microM; MNS = 1.2 microM; C 2921: MHS = 4 microM; MNS = 3.8 microM), and were 4-8 times lower than those of torasemide (MHS = 13 microM; MNS = 31 microM, P less than 0.01) and 50-60 times lower than those of bumetanide (MHS = 145 microM; MNS = 206 microM, P less than 0.05) taken as reference compounds. Their ability to reduce the development rate of hypertension was tested both in MHS and in Okamoto spontaneously hypertensive rats (SHR) strain, in which cotransport alterations are opposite to those of MHS. Both torasemide derivatives (7.5 mg.kg-1 os per day) prevented development of hypertension in the two strains. The time course of this hypotensive activity was faster and the percentage of blood pressure fall greater in MHS (20-25%) than in SHR rats (12-15%), even though the absolute value of blood pressure fall was similar in MHS (JDL 961 = -17 mm Hg; C 2921 = -30 mm Hg) and SHR (JDL 961 = -25 mm Hg; C 2921 = -20 mm Hg). A superimposable effect of bumetanide was observed in the two strains, but at 8 times higher daily dose (60 mg.kg-1). These results suggest that new loop diuretics can be selected for their antihypertensive activity on the basis of their in vitro potency in inhibiting the Na+,2Cl-,K+.

The use of primary cell culture techniques to predict the function of native respiratory epithelia was tested in studies of dog airway epithelia. Epithelial cells from Cl- secretory (tracheal) and Na+ absorptive (bronchial) airway regions were isolated by enzymatic digestion, plated on collagen matrices, and maintained in serum-free, hormone-supplemented media. Transepithelial and intracellular studies showed that both the tracheal and bronchial culture preparations exhibited bioelectric parameters quantitatively similar to those of intact tissues. Similar to the native tissue, the tracheal preparation exhibited an equivalent short-circuit circuit (Ieq) that was sensitive to inhibitors of Cl- transport (bumetanide, diphenylamine carboxylic acid) but was insensitive to an inhibitor of Na+ transport, amiloride. In contrast, the bronchial preparation, like the native tissue, exhibited an Ieq sensitive to amiloride but insensitive to bumetanide. As compared with the trachea, the bronchial (absorptive) epithelium is characterized by 1) a large amiloride-sensitive cellular conductance and 2) a relatively depolarized basolateral membrane. We conclude that this primary cell culture technique provides epithelial preparations comparable to the native tissue and suitable for quantitative studies of regional differences in ion transport function.

The use of primary cell culture techniques to predict the function of native respiratory epithelia was tested in studies of dog airway epithelia. Epithelial cells from Cl- secretory (tracheal) and Na+ absorptive (bronchial) airway regions were isolated by enzymatic digestion, plated on collagen matrices, and maintained in serum-free, hormone-supplemented media. Transepithelial and intracellular studies showed that both the tracheal and bronchial culture preparations exhibited bioelectric parameters quantitatively similar to those of intact tissues. Similar to the native tissue, the tracheal preparation exhibited an equivalent short-circuit circuit (Ieq) that was sensitive to inhibitors of Cl- transport (bumetanide, diphenylamine carboxylic acid) but was insensitive to an inhibitor of Na+ transport, amiloride. In contrast, the bronchial preparation, like the native tissue, exhibited an Ieq sensitive to amiloride but insensitive to bumetanide. As compared with the trachea, the bronchial (absorptive) epithelium is characterized by 1) a large amiloride-sensitive cellular conductance and 2) a relatively depolarized basolateral membrane. We conclude that this primary cell culture technique provides epithelial preparations comparable to the native tissue and suitable for quantitative studies of regional differences in ion transport function.

The use of primary cell culture techniques to predict the function of native respiratory epithelia was tested in studies of dog airway epithelia. Epithelial cells from Cl- secretory (tracheal) and Na+ absorptive (bronchial) airway regions were isolated by enzymatic digestion, plated on collagen matrices, and maintained in serum-free, hormone-supplemented media. Transepithelial and intracellular studies showed that both the tracheal and bronchial culture preparations exhibited bioelectric parameters quantitatively similar to those of intact tissues. Similar to the native tissue, the tracheal preparation exhibited an equivalent short-circuit circuit (Ieq) that was sensitive to inhibitors of Cl- transport (bumetanide, diphenylamine carboxylic acid) but was insensitive to an inhibitor of Na+ transport, amiloride. In contrast, the bronchial preparation, like the native tissue, exhibited an Ieq sensitive to amiloride but insensitive to bumetanide. As compared with the trachea, the bronchial (absorptive) epithelium is characterized by 1) a large amiloride-sensitive cellular conductance and 2) a relatively depolarized basolateral membrane. We conclude that this primary cell culture technique provides epithelial preparations comparable to the native tissue and suitable for quantitative studies of regional differences in ion transport function.

© 2019 Goubert, Altvater, Rovira, Khalilov, Mazzarino, Sebastiani, Schaefer, Rivera and Pellegrino. Brain trauma triggers a cascade of deleterious events leading to enhanced incidence of drug resistant epilepsies, depression, and cognitive dysfunctions. The underlying mechanisms leading to these alterations are poorly understood and treatment that attenuates those sequels are not available. Using controlled-cortical impact as an experimental model of brain trauma in adult mice, we found a strong suppressive effect of the sodium-potassium-chloride importer (NKCC1) specific antagonist bumetanide on the appearance of depressive-like behavior. We demonstrate that this alteration in behavior is associated with an impairment of post-traumatic secondary neurogenesis within the dentate gyrus of the hippocampus. The mechanism mediating the effect of bumetanide involves early transient changes in the expression of chloride regulatory proteins and qualitative changes in GABA(A) mediated transmission from hyperpolarizing to depolarizing after brain trauma. This work opens new perspectives in the early treatment of human post-traumatic induced depression. Our results strongly suggest that bumetanide might constitute an efficient prophylactic treatment to reduce neurological and psychiatric consequences of brain trauma.