Acetazolamide: Old drug, new evidence?

Sodium bicarbonate use in the treatment of idiopathic intracranial hypertension

PURPOSE

This retrospective case-control study from 2008 to 2022 aimed to determine the effect of adjunctive sodium bicarbonate (NaHCO3) on treatment outcomes of and side effects of acetazolamide (ACZ) for the treatment of idiopathic intracranial hypertension (IIH).

SUBJECTS/METHODS

Retrospective data was collected via chart review. 288 eyes of 144 patients with IIH, including those taking ACZ alone (control group, n = 89) vs. ACZ and NaHCO3 (treatment group, n = 56). The primary outcome measure was time to IIH resolution. Secondary outcomes included retinal nerve fibre layer thickness (RNFL), visual field mean deviation (VFMD), visual acuity (VA), discontinuation ACZ, and patient-reported side effects of ACZ.

RESULTS

Cox proportional hazards model for the primary outcome yielded a hazard ratio of 0.800, which was statistically insignificant (95% CI, 0.57-1.13; p = 0.200). There was no significant difference between groups when comparing RNFL, VFMD, VA, surgical intervention, or discontinuation of ACZ. The treatment group was more likely to experience side effects from ACZ prior to starting sodium bicarbonate therapy (p < 0.001). Among the treatment group, 92.7% remained on NaHCO3 until IIH resolution, and 9 of 12 (75%) subjects reported significant improvement in ACZ-related side effects.

CONCLUSION

Sodium bicarbonate does not appear to impact treatment outcomes in patients taking acetazolamide for IIH. Sodium bicarbonate may represent a reasonable adjunctive medication to help mitigate acetazolamide-related side effects in this group of patients.

Inflammation severity, rather than respiratory failure, is strongly associated with mortality of ARDS patients in high-altitude ICUs

Introduction

In high-altitude cities located above 2,500 m, hospitals face a concerning mortality rate of over 50% among intensive care unit (ICU) patients with acute respiratory distress syndrome (ARDS). This elevated mortality rate is largely due to the absence of altitude-specific medical protocols that consider the unique physiological adaptations of high-altitude residents to hypoxic conditions. This study addresses this critical gap by analyzing demographic, clinical, sex-specific, and preclinical data from ICUs in Bogotá, Colombia (2,650 m) and El Alto, Bolivia (4,150 m).

Methods

A cohort of seventy ARDS patients, aged 18 and older, was evaluated within 24 h of ICU admission. Data collected included demographic information (age, sex), clinical characteristics (primary pathology, weight, height), vital signs, respiratory variables, cardiorespiratory parameters, blood count results, inflammatory markers, severity assessment scores, and comorbidities. Advanced statistical analyses, such as multivariate logistic regression and principal component analysis, were utilized to identify key clinical predictors of ARDS-related mortality.

Results

Our findings indicate that in high-altitude ICUs, monitoring inflammatory markers may be more beneficial for improving ARDS survival rates than emphasizing respiratory failure markers. Unexpectedly, we found no significant differences in clinical outcomes between altitudes of 2,650 and 4,150 m or between male and female patients.

Conclusion

The study concludes that, in high-altitude settings, ARDS patient survival in ICUs is more closely associated with managing inflammatory responses than with focusing solely on respiratory parameters. Further large-scale studies are recommended to validate the impact of inflammatory marker monitoring on survival outcomes in high-altitude ICUs.

Effects of acetazolamide on intracranial pressure and brain tissue oxygenation on patients with acute brain injury: A pilot physiological study

The effect of acetazolamide on regional brain tissue oxygenation in patients with acute brain injury (ABI) is unknown. We studied adult patients with ABI who received acetazolamide as per the treating physician's decision and had ICP and brain oxygen pressure (PbtO2) monitoring. Baseline measurements of ICP, cerebral perfusion pressure (CPP), and PbtO2 were taken before administering acetazolamide; subsequent measurements were recorded every 5 min for a total of 20 min. Mean cerebral blood velocities (FVm) and pulsatility index (PI) were measured using transcranial color-coded duplex (TCCD) sonography at baseline and after 20 min. Fourteen patients with subarachnoid hemorrhage (n = 6), traumatic brain injury (n = 7), and intracranial hemorrhage (n = 1) were included. Following administration of acetazolamide, ICP showed a significant increase within 20 min (p < 0.001), with no significant change in CPP (p = 0.08). PbtO2 demonstrated a significant increase (p < 0.001), with a noticeable change observed at 10 min after acetazolamide administration (15 [14-17] vs. 28 [26-30] mmHg). Additionally, FVm exhibited a significant increase (p < 0.001), and PI showed a reduction (p < 0.001). Administration of acetazolamide in ABI patients resulted in a significant increase in brain oxygenation, associated with a rise in ICP and FVm, suggesting increased cerebral volume and vasodilation.

Acetazolamide and human carbonic anhydrases: retrospect, review and discussion of an intimate relationship

Acetazolamide (AZM) is a strong pharmacological sulphonamide-type (R-SO2-NH2, pKa 7.2) inhibitor of the activity of several carbonic anhydrase (CA) isoforms, notably of renal CA II (Ki, 12 nM) and CA IV (Ki, 74 nM). AZM is clinically used for about eighty years in various diseases including epilepsy and glaucoma. Pharmacological AZM increases temporarily the urinary excretion of bicarbonate (HCO3-) and sodium ions (Na+) and sustainably the urinary pH. AZM is excreted almost unchanged over several hours at high rates in the urine. Closely parallel concentrations of circulating and excretory AZM are observed upon administration of therapeutical doses of AZM. In a proof-of-principle study, we investigated the effects of the ingestion of a 250-mg AZM-containing tablet by a healthy volunteer on the urinary excretion of organic and inorganic substances over 5 h (range, 0, 0.5, 1, 1.5, 2, 3, 4, 5 h). Measured analytes included: AZM, amino acids and their metabolites such as guanidinoacetate, i.e. the precursor of creatine, of asymmetrically (ADMA) and symmetrically (SDMA) dimethylated arginine, nitrite (O = N-O-, pKa 3.4) and nitrate (O2N-O-, pKa -1.37), the major metabolites of nitric oxide (NO), the C-H acidic malondialdehyde (MDA; (CHO)2CH2, pKa 4.5), and creatinine for correction of analytes excretion. All analytes were measured by validated isotopologues using gas chromatography-mass spectrometry (GC-MS) methods. AZM excretion in the urine reached its maximum value after 2 h and was fairly stable for the next 3 h. Time series analysis by the ARIMA method was performed. AZM ingestion increased temporarily the urinary excretion of the amino acids Leu + Ile, nitrite and nitrate, decreased temporarily the urinary excretion of other amino acids. AZM decreased sustainably the urinary excretion of MDA, a biomarker of oxidative stress (i.e. lipid peroxidation). Whether this decrease is due to inhibition of the excretion of MDA or attenuation of oxidative stress by AZM is unknown. The acute and chronic effects of AZM on the urinary excretion of electrolytes and physiological substances reported in the literature are discussed in depth in the light of its extraordinary pharmacokinetics and pharmacodynamics. Tolerance development/drug resistance to AZM in chronic use and potential mechanisms are also addressed.

Efficacy of Acetazolamide for Treatment of Iatrogenic, Traumatic, and Spontaneous Cerebrospinal Fluid Leaks of the Anterior Skull Base: A Systematic Review

A cerebral spinal fluid (CSF) leak from the anterior skull base is a challenging neurosurgical issue that requires prompt recognition and treatment. Options for treatment include medical and surgical repair. A systematic review was performed screening for both retrospective and prospective clinical studies evaluating the efficacy of acetazolamide in the event of CSF leaks of the anterior skull base.  We initially screened a total of 149 studies for inclusion, and 25 of them met the inclusion criteria. We included four studies on iatrogenic CSF leaks caused by surgery of the anterior cranial fossa, three studies on traumatic CSF leaks, and 18 studies on spontaneous CSF leaks caused by idiopathic intracranial hypertension (IIH). In the event of an iatrogenic CSF leak, 68 patients had undergone an endoscopic endonasal approach. CSF diversion and high-volume lumbar puncture were used frequently with adjunct acetazolamide administration. In the event of trauma, 187 patients were evaluated across the three included studies. Acetazolamide treatment was used as a single approach and effectively controlled CSF leaks. For spontaneous CSF leaks, acetazolamide is frequently used to increase the efficacy of surgical repair. Of the 431 patients, 327 received temporary CSF diversion in addition to acetazolamide. Surgical repair was the primary treatment in 277 patients. Acetazolamide should be considered as a treatment option in patients with CSF leak secondary to surgery of the anterior cranial fossa, trauma, and idiopathic causes.

Novel benzenesulfonamides containing a dual triazole moiety with selective carbonic anhydrase inhibition and anticancer activity

A series of sulfonamides incorporating a 1,2,3-triazolyloxime substituted 1,2,3-triazolyl moiety were conceptualized and synthesized as human carbonic anhydrase (hCA) inhibitors. The synthesized small structures, denoted 7a through 7o, exhibited moderate inhibitory effects against the tumor-associated isoforms hCA IX and hCA XII compared to the well-known hCA inhibitor acetazolamide. In contrast, these molecules demonstrated higher potency and a diverse range of selectivity against the cytosolic isoforms hCA I and hCA II. Notably, the 4-hydroxyphenyl derivative (compound 7dversus cytosolic isoforms), the 4-acetylphenyl derivative (compound 7o), and the phenyl derivative (compound 7a) emerged as the most potent and selective inhibitors in this series, with inhibition constants (K I) of 47.1, 35.9, 170.0, and 149.9 nM, respectively, against hCA I, II, IX, and XII. Further cytotoxicity assays of compounds 7a-o against cancer cell lines Hep3B and A549, as well as normal cell line L929, were conducted to assess their selectivity towards malignant cells. Compounds 7d, 7g, and 7k exhibited selective cytotoxicity towards the Hep3B cell line, with reduced selectivity towards A549, whereas compound 7j demonstrated higher selectivity for the A549 cell line. Additionally, molecular docking studies were performed to elucidate the binding modes of these compounds within the active sites of hCAs, revealing crucial interactions that underpin their significant activity and selectivity for the tumor-specific isoforms.

Effectiveness of add-on acetazolamide in children with drug-resistant CHD2-related epilepsy and in a zebrafish CHD2 model

CHD2-related epilepsy is characterized by early-onset photosensitive myoclonic epilepsy with developmental delay and a high rate of pharmacoresistance. We sought to evaluate the efficacy of acetazolamide (ACZ) in CHD2-related epilepsy, due to ACZ's unexpected efficacy in our first patient harboring a pathogenic CHD2 variant. We collected patients from different Eastern European countries with drug-resistant CHD2-related epilepsy who were then treated with ACZ. Patients underwent video EEG before and during ACZ treatment. In a zebrafish model of CHD2-related epilepsy, ictal-like events were recorded 5 days post-fertilization after overnight ACZ exposure. Developmental delay preceded the onset of seizures in 10 of the 12 patients. Four had ataxia, and 6 exhibited autistic features. Seizures, primarily myoclonic, began at an average age of 3.4 years and were photosensitive in all 12 patients. Add-on ACZ treatment controlled photosensitive seizures in all patients: 6 became seizure-free, and in the remaining 6, seizure frequency decreased by over 75%. Four patients transitioned to ACZ monotherapy. The median follow-up was 13 months. In the zebrafish model, ACZ exposure reduced ictal-like events by 72%. ACZ, a well-tolerated and cost-effective medication, could be a good option for CHD2-related epilepsy, predominantly manifesting with myoclonic seizures and photosensitivity. PLAIN LANGUAGE SUMMARY: Epilepsy associated with CHD2 mutations is often pharmacoresistant and associated with developmental delay and eventually ataxia. There are several generalized seizure types, including generalized tonic-clonic seizures, but the most characteristic are jerks triggered by light stimulation. We collected 12 patients who received acetazolamide, a drug usually given as a diuretic and registered as a mild antiseizure medication. All jerks triggered by light disappeared while the frequency of spontaneous seizures decreased by over 75%. Further studies are needed to confirm this promising finding and identify the mechanism by which an old compound seems to have such a specific antiseizure effect.

Preserflo MicroShunt versus Trabeculectomy: Efficacy and Surgical Success within a Heterogenous Patient Cohort

To compare success rates of trabeculectomy (TE) and Preserflo MicroShunt (PMS) in heterogenous glaucoma cohorts with regards to different pre- and postoperative therapeutic regimens. Data of 187 glaucoma patients who either received TE (73 eyes) or PMS implantation (114 eyes) between January 2018 and December 2022 were retrospectively evaluated. Surgical success and failure rates were analyzed within six months of follow-up. Intraocular pressure (IOP) development over the course of follow-up was compared between both groups. Tertiary outcome measures were best-corrected visual acuity (BCVA), number and type of medications, frequency of postoperative complications and revision surgeries. Outcome measures underwent additional assessment based on subgroup categorizations, and failure time hazard ratios were computed. The success rates were comparable between both procedures (TE: 54.1%, PMS: 60.0%; p = 0.17). Both procedures showed significant IOP reduction (p < 0.01); however, overall IOP reduction was greater in the TE group than in the PMS group (TE: Reduction by 12 mmHg (188.9%), PMS: Reduction by 7 mmHg (51.3%); p = 0.01). The number of topical medications decreased significantly in both groups over the course of follow-up (TE: 4 to 0, PMS: 3 to 0; p < 0.01). While the number of complications and revision surgeries were similar in both groups, the time interval until the first revision surgery within the TE group was significantly shorter (TE: 13.5 d, PMS: 163 d; p = 0.01) than within the PMS group. No difference could be detected between TE and PMS with regard to the follow-up regimen. In particular, there was no significant difference in the need for 5-floururacil injections postoperatively (p = 0.29). Less invasive glaucoma surgery with the PMS appeared comparable to the TE within a heterogenous glaucoma cohort with regards to IOP development and freedom from medication.

Metabolic alkalosis: a new red flag in status epilepticus

BACKGROUND

Status epilepticus (SE) is a heterogeneous neurological emergency with significant variability in prognosis, influenced by underlying disease and pathophysiological context. Acid-base disturbances are common in critically ill patients, yet their distribution and impact in SE patients remain poorly understood.

METHODS

This was an observational cohort study including non-hypoxic SE patients with available blood gas analysis within the first 24 h of SE, treated at the University Hospital of Geneva, Switzerland between 2015 and 2023. Acid-base disturbances were classified using the Henderson-Hasselbalch equation, with prevalent metabolic alkalosis confirmed through the Stewart approach. Primary outcomes were in-hospital mortality, Glasgow Outcome Scale (GOS) at discharge, and return to premorbid neurologic function.

FINDINGS

Among 540 SE patients, 365 were included. Half of patients exhibited acid-base disturbances within the initial 24 h of SE, with metabolic and respiratory acidosis being the most prevalent, though not prognostically significant. After correction for possible confounders, metabolic alkalosis (6%) was associated with increased in-hospital mortality (P = 0.011; OR = 4.87, 95% CI = 1.29-7.84), worse GOS (P = 0.012; OR = 3.18, 95% CI = 1.29-7.84), and reduced likelihood of returning to premorbid function (P = 0.017; OR = 3.30, CI95% = 1.24-8.80). Following the Stewart approach, 9% of patients had predominant metabolic alkalosis, associated with worse GOS (P = 0.005; OR:3.37, 95%CI = 1.45-7.82), and reduced chance of returning to baseline (P = 0.012; OR = 3.29, CI95% = 1.30-8.32). Metabolic alkalosis was related to hypoalbuminemia and lower serum potassium.

CONCLUSION

Metabolic alkalosis strongly predicts mortality and adverse functional outcome in SE patients. Prospective studies should assess whether early detection and correction of metabolic alkalosis and related electrolyte imbalances can improve SE prognosis.

Case for supporting astrocyte energetics in glucose transporter 1 deficiency syndrome

In glucose transporter 1 deficiency syndrome (Glut1DS), glucose transport into brain is reduced due to impaired Glut1 function in endothelial cells at the blood-brain barrier. This can lead to shortages of glucose in brain and is thought to contribute to seizures. Ketogenic diets are the first-line treatment and, among many beneficial effects, provide auxiliary fuel in the form of ketone bodies that are largely metabolized by neurons. However, Glut1 is also the main glucose transporter in astrocytes. Here, we review data indicating that glucose shortage may also impact astrocytes in addition to neurons and discuss the expected negative biochemical consequences of compromised astrocytic glucose transport for neurons. Based on these effects, auxiliary fuels are needed for both cell types and adding medium chain triglycerides (MCTs) to ketogenic diets is a biochemically superior treatment for Glut1DS compared to classical ketogenic diets. MCTs provide medium chain fatty acids (MCFAs), which are largely metabolized by astrocytes and not neurons. MCFAs supply energy and contribute carbons for glutamine and γ-aminobutyric acid synthesis, and decanoic acid can also block α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid glutamate receptors. MCTs do not compete with metabolism of ketone bodies mostly occurring in neurons. Triheptanoin, an anaplerotic but also gluconeogenic uneven MCT, may be another potential addition to ketogenic diets, although maintenance of "ketosis" can be difficult. Gene therapy has also targeted both endothelial cells and astrocytes. Other approaches to increase fuel delivery to the brain currently investigated include exchange of Glut1DS erythrocytes with healthy cells, infusion of lactate, and pharmacological improvement of glucose transport. In conclusion, although it remains difficult to assess impaired astrocytic energy metabolism in vivo, astrocytic energy needs are most likely not met by ketogenic diets in Glut1DS. Thus, we propose prospective studies including monitoring of blood MCFA levels to find optimal doses for add-on MCT to ketogenic diets and assessing of short- and long-term outcomes.

Acetazolamide-induced pulmonary oedema: A disproportionality analysis from the EudraVigilance database

To our knowledge, no prior study has analysed a possible association between acetazolamide and pulmonary oedema. The aim of this study was to use data from the EudraVigilance to detect a safety signal for acetazolamide-induced pulmonary oedema. We performed a disproportionality analysis (case-noncase method), calculating reporting odds ratios (RORs) up to 22 February 2024. Among 11 684 208 spontaneous cases of adverse reactions registered in EudraVigilance, 38 275 were pulmonary oedemas. Acetazolamide was involved in 31 cases. In more than half of those cases, the patients received a single dose of acetazolamide after undergoing cataract surgery: latency was 10-90 min. Remarkably, there were five cases of positive rechallenge and six cases resulted in death. The ROR for acetazolamide was 3.63 (95% CI 2.55-5.17). Disproportionality was also observed in VigiBase®: ROR 4.44 (95% CI 3.34-5.90). Our study confirms a signal that suggests a risk of serious pulmonary oedema associated with acetazolamide.

Synthesis and Enzymatic Evaluation of a Small Library of Substituted Phenylsulfonamido-Alkyl Sulfamates towards Carbonic Anhydrase II

A small library of 79 substituted phenylsulfonamidoalkyl sulfamates, 1b-79b, was synthesized starting from arylsulfonyl chlorides and amino alcohols with different numbers of methylene groups between the hydroxyl and amino moieties yielding intermediates 1a-79a, followed by the reaction of the latter with sulfamoyl chloride. All compounds were screened for their inhibitory activity on bovine carbonic anhydrase II. Compounds 1a-79a showed no inhibition of the enzyme, in contrast to sulfamates 1b-79b. Thus, the inhibitory potential of compounds 1b-79b towards this enzyme depends on the substituent and the substitution pattern of the phenyl group as well as the length of the spacer. Bulkier substituents in the para position proved to be better for inhibiting CAII than compounds with the same substituent in the meta or ortho position. For many substitution patterns, compounds with shorter spacer lengths were superior to those with long chain spacers. Compounds with shorter spacer lengths performed better than those with longer chain spacers for a variety of substitution patterns. The most active compound held inhibition constant as low as Ki = 0.67 μM (for 49b) and a tert-butyl substituent in para position and acted as a competitive inhibitor of the enzyme.

Acetazolamide as an effective treatment for pilomotor seizures in autoimmune encephalitis

Pilomotor seizures are strongly associated with autoimmune encephalitis (AE), particularly anti-LGI1 encephalitis. The carbonic anhydrase inhibitor acetazolamide may have special efficacy for treating AE-associated pilomotor seizures. Six patients with AE (five anti-LGI1, one seronegative) and temporal lobe pilomotor seizures (five with seizures inducible by hyperventilation) were treated with acetazolamide, administered in a cycling (2-days-ON, 4-days-OFF) regimen to offset tolerance. Seizures were assessed during epilepsy monitoring unit (EMU) recordings in four inpatients (one of whom also maintained an outpatient seizure diary chronicling 1203 seizures over 1079 days); two outpatients self-reported seizure frequencies. The extended diary revealed an inverse correlation between acetazolamide and proportion of seizures/day: 6%, 2% (days 1, 2 ON); 3%, 13%, 31%, 45% (days 1, 2, 3, 4 OFF). This patient later developed focal status epilepticus upon wean of antiseizure medications during a seropositive AE relapse that was remarkably aborted with acetazolamide monotherapy. The other three EMU patients averaged .56 seizures/day ON, and 3.81 seizures/day OFF (p = .004). The two outpatients reported seizure reductions from 3-5/day to 2/week, and 15-20/day to none, respectively, after initiation of cycling acetazolamide. Likely related to cerebral CO2/pH sensitivity, acetazolamide can be unusually effective in controlling pilomotor seizures in AE, chronically or in acute settings.

Synthesis, In Vivo Anticonvulsant Activity Evaluation and In Silico Studies of Some Quinazolin-4(3H)-One Derivatives

Two series, "a" and "b", each consisting of nine chemical compounds, with 2,3-disubstituted quinazolin-4(3H)-one scaffold, were synthesized and evaluated for their anticonvulsant activity. They were investigated as dual potential positive allosteric modulators of the GABAA receptor at the benzodiazepine binding site and inhibitors of carbonic anhydrase II. Quinazolin-4(3H)-one derivatives were evaluated in vivo (D1-3 = 50, 100, 150 mg/kg, administered intraperitoneally) using the pentylenetetrazole (PTZ)-induced seizure model in mice, with phenobarbital and diazepam, as reference anticonvulsant agents. The in silico studies suggested the compounds act as anticonvulsants by binding on the allosteric site of GABAA receptor and not by inhibiting the carbonic anhydrase II, because the ligands-carbonic anhydrase II predicted complexes were unstable in the molecular dynamics simulations. The mechanism targeting GABAA receptor was confirmed through the in vivo flumazenil antagonism assay. The pentylenetetrazole experimental anticonvulsant model indicated that the tested compounds, 1a-9a and 1b-9b, present a potential anticonvulsant activity. The evaluation, considering the percentage of protection against PTZ, latency until the onset of the first seizure, and reduction in the number of seizures, revealed more favorable results for the "b" series, particularly for compound 8b.

The Effects of Acetazolamide on Cerebral Hemodynamics in Adult Patients with an Acute Brain Injury: A Systematic Review

BACKGROUND

Acetazolamide is a non-competitive inhibitor of carbonic anhydrase, an enzyme expressed in different cells of the central nervous system (CNS) and involved in the regulation of cerebral blood flow (CBF). The aim of this review was to understand the effects of acetazolamide on CBF, intracranial pressure (ICP) and brain tissue oxygenation (PbtO2) after an acute brain injury (ABI).

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement (PRISMA), we performed a comprehensive, computer-based, literature research on the PubMed platform to identify studies that have reported the effects on CBF, ICP, or PbtO2 of acetazolamide administered either for therapeutic or diagnostic purposes in patients with subarachnoid hemorrhage, intracerebral hemorrhage, traumatic brain injury, and hypoxic-ischemic encephalopathy.

RESULTS

From the initial search, 3430 records were identified and, through data selection, 11 of them were included for the qualitative analysis. No data on the effect of acetazolamide on ICP or PbtO2 were found. Cerebral vasomotor reactivity (VMR-i.e., the changing in vascular tone due to a vasoactive substance) to acetazolamide tends to change during the evolution of ABI, with the nadir occurring during the subacute stage. Moreover, VMR reduction was correlated with clinical outcome.

CONCLUSIONS

This systematic review showed that the available studies on the effects of acetazolamide on brain hemodynamics in patients with ABI are scarce. Further research is required to better understand the potential role of this drug in ABI patients.

A concise study of acetazolamide in glucose transporter type 1 deficiency (G1D) epilepsy

Epilepsy constitutes the most common paroxysmal manifestation of glucose transporter type 1 deficiency (G1D) and is generally considered medication-refractory. It can also prove therapeutic diet-resistant. We examined acetazolamide effects in G1D motivated by several longstanding and recent observations: First, the electrographic spike-waves characteristic of absence seizures often resemble those of G1D and, since the 1950s, they have occasionally been treated successfully with acetazolamide, well before G1D was segregated from absence epilepsy as a distinct syndrome. Second, synaptic inhibitory neuron failure characterizes G1D and, in other experimental models, this can be ameliorated by drugs that modify cellular chloride gradient such as acetazolamide. Third, acetazolamide potently stimulates model cell glucose transport in vitro. Seventeen antiepileptic drug or therapeutic diet-refractory individuals with G1D treated with acetazolamide were thus identified via medical record review complemented by worldwide individual survey. Acetazolamide was tolerated and decreased seizures in 76% of them, with 58% of all persons studied experiencing seizure reductions by more than one-half, including those who first manifested myoclonic-astatic epilepsy or infantile spams. Eighty-eight percent of individuals with G1D continued taking acetazolamide for over 6 months, indicating sustained tolerability and efficacy. The results provide a novel avenue for the treatment and mechanistic investigation of G1D.

Long-Term Outcomes of the PRESERFLO MicroShunt Implant in a Heterogeneous Glaucoma Cohort

The Preserflo MicroShunt represents a novel glaucoma treatment device, necessitating long-term follow-up data to accurately assess its efficacy. The aim of this study is to report real-world data of a heterogenous glaucoma cohort who received Preserflo implantation at a specialized glaucoma clinic. A total of 160 eyes of 160 patients who underwent Preserflo MicroShunt implantation were retrospectively enrolled in this study. Patient characteristics, as well as success and failure rates, were assessed. The numbers of adverse events and revision procedures were recorded, along with any reduction in supplementary medication. The progression of intraocular pressure (IOP) was assessed over the course of 12 months, and fluctuations were analyzed. The overall success rate was 61.9% (complete success: 51.3%, qualified success: 10.6%). Revision surgery was performed in 25% of cases. Excessive hypotony occurred postoperatively in 54.4% of patients and regressed after 7 days in 88.8% of all cases. Median IOP decreased from 22 (interquartile range (IQR): 17-27) mmHg preoperatively to 14 (IQR 12-16) mmHg at 12 months postoperatively (p < 0.01). The median number of antiglaucomatous agents decreased from three to zero at latest follow-up. The Preserflo MicroShunt achieved a noticeable reduction in IOP over the course of 12 months in glaucoma patients, irrespective of disease severity or disease subtype. The frequency of postoperative adverse events and number for revision surgeries over the course of the follow-up period were low.

Bumetanide potentiates the anti-seizure and disease-modifying effects of midazolam in a noninvasive rat model of term birth asphyxia

Birth asphyxia and the resulting hypoxic-ischemic encephalopathy (HIE) are highly associated with perinatal and neonatal death, neonatal seizures, and an adverse later-life outcome. Currently used drugs, including phenobarbital and midazolam, have limited efficacy to suppress neonatal seizures. There is a medical need to develop new therapies that not only suppress neonatal seizures but also prevent later-life consequences. We have previously shown that the loop diuretic bumetanide does not potentiate the effects of phenobarbital in a rat model of birth asphyxia. Here we compared the effects of bumetanide (0.3 or 10 mg/kg i.p.), midazolam (1 mg/kg i.p.), and a combination of bumetanide and midazolam on neonatal seizures and later-life outcomes in this model. While bumetanide at either dose was ineffective when administered alone, the higher dose of bumetanide markedly potentiated midazolam's effect on neonatal seizures. Median bumetanide brain levels (0.47-0.53 µM) obtained with the higher dose were in the range known to inhibit the Na-K-Cl-cotransporter NKCC1 but it remains to be determined whether brain NKCC1 inhibition was underlying the potentiation of midazolam. When behavioral and cognitive alterations were examined over three months after asphyxia, treatment with the bumetanide/midazolam combination, but not with bumetanide or midazolam alone, prevented impairment of learning and memory. Furthermore, the combination prevented the loss of neurons in the dentate hilus and aberrant mossy fiber sprouting in the CA3a area of the hippocampus. The molecular mechanisms that explain that bumetanide potentiates midazolam but not phenobarbital in the rat model of birth asphyxia remain to be determined.

Fundamental Neurochemistry Review: GABAA receptor neurotransmission and epilepsy: Principles, disease mechanisms and pharmacotherapy

Epilepsy is a common neurological disorder associated with alterations of excitation-inhibition balance within brain neuronal networks. GABA_A receptor neurotransmission is the most prevalent form of inhibitory neurotransmission and is strongly implicated in both the pathophysiology and treatment of epilepsy, serving as a primary target for antiseizure medications for over a century. It is now established that GABA exerts a multifaceted influence through an array of GABA_A receptor subtypes that extends far beyond simply negating excitatory activity. As the role of GABA_A neurotransmission within inhibitory circuits is elaborated, this will enable the development of precision therapies that correct the network dysfunction underlying epileptic pathology.

Small Structural Differences Govern the Carbonic Anhydrase II Inhibition Activity of Cytotoxic Triterpene Acetazolamide Conjugates

Acetylated triterpenoids betulin, oleanolic acid, ursolic acid, and glycyrrhetinic acid were converted into their succinyl-spacered acetazolamide conjugates. These conjugates were screened for their inhibitory activity onto carbonic anhydrase II and their cytotoxicity employing several human tumor cell lines and non-malignant fibroblasts. As a result, the best inhibitors were derived from betulin and glycyrrhetinic acid while those derived from ursolic or oleanolic acid were significantly weaker inhibitors but also of diminished cytotoxicity. A betulin-derived conjugate held a K_i = 0.129 μM and an EC₅₀ = 8.5 μM for human A375 melanoma cells.