Summary Background End-stage kidney disease is a leading cause of morbidity and mortality worldwide. Prevalence of the disease and worldwide use of renal replacement therapy (RRT) are expected to ...rise sharply in the next decade. We aimed to quantify estimates of this burden. Methods We systematically searched Medline for observational studies and renal registries, and contacted national experts to obtain RRT prevalence data. We used Poisson regression to estimate the prevalence of RRT for countries without reported data. We estimated the gap between needed and actual RRT, and projected needs to 2030. Findings In 2010, 2·618 million people received RRT worldwide. We estimated the number of patients needing RRT to be between 4·902 million (95% CI 4·438–5·431 million) in our conservative model and 9·701 million (8·544–11·021 million) in our high-estimate model, suggesting that at least 2·284 million people might have died prematurely because RRT could not be accessed. We noted the largest treatment gaps in low-income countries, particularly Asia (1·907 million people needing but not receiving RRT; conservative model) and Africa (432 000 people; conservative model). Worldwide use of RRT is projected to more than double to 5·439 million (3·899–7·640 million) people by 2030, with the most growth in Asia (0·968 million to a projected 2·162 million 1·571–3·014 million). Interpretation The large number of people receiving RRT and the substantial number without access to it show the need to both develop low-cost treatments and implement effective population-based prevention strategies. Funding Australian National Health and Medical Research Council.
Decreased but Diverse Activity of Cortical and Thalamic Neurons in Consciousness-Impairing Rodent Absence Seizures
McCafferty C, Gruenbaum BF, Tung R, Li JJ, Zheng X, Salvino P, Vincent P, Kratochvil ...Z, Ryu JH, Khalaf A, Swift K, Akbari R, Islam W, Antwi P, Johnson EA, Vitkovskiy P, Sampognaro J, Freedman IG, Kundishora A, Depaulis A, David F, Crunelli V, Sanganahalli BG, Herman P, Hyder F, Blumenfeld H. Nat Commun. 2023;14(1):117. doi:10.1038/s41467-022-35535-4
Absence seizures are brief episodes of impaired consciousness, behavioral arrest, and unresponsiveness, with yet-unknown neuronal mechanisms. Here we report that an awake female rat model recapitulates the behavioral, electroencephalographic, and cortical functional magnetic resonance imaging characteristics of human absence seizures. Neuronally, seizures feature overall decreased but rhythmic firing of neurons in cortex and thalamus. Individual cortical and thalamic neurons express one of four distinct patterns of seizure-associated activity, one of which causes a transient initial peak in overall firing at seizure onset, and another which drives sustained decreases in overall firing. 40-60 s before seizure onset there begins a decline in low frequency electroencephalographic activity, neuronal firing, and behavior, but an increase in higher frequency electroencephalography and rhythmicity of neuronal firing. Our findings demonstrate that prolonged brain state changes precede consciousness-impairing seizures, and that during seizures distinct functional groups of cortical and thalamic neurons produce an overall transient firing increase followed by a sustained firing decrease, and increased rhythmicity.
Acute kidney injury is common in critically ill patients, many of whom receive renal-replacement therapy. However, the most effective timing for the initiation of such therapy remains uncertain.
We ...conducted a multinational, randomized, controlled trial involving critically ill patients with severe acute kidney injury. Patients were randomly assigned to receive an accelerated strategy of renal-replacement therapy (in which therapy was initiated within 12 hours after the patient had met eligibility criteria) or a standard strategy (in which renal-replacement therapy was discouraged unless conventional indications developed or acute kidney injury persisted for >72 hours). The primary outcome was death from any cause at 90 days.
Of the 3019 patients who had undergone randomization, 2927 (97.0%) were included in the modified intention-to-treat analysis (1465 in the accelerated-strategy group and 1462 in the standard-strategy group). Of these patients, renal-replacement therapy was performed in 1418 (96.8%) in the accelerated-strategy group and in 903 (61.8%) in the standard-strategy group. At 90 days, death had occurred in 643 patients (43.9%) in the accelerated-strategy group and in 639 (43.7%) in the standard-strategy group (relative risk, 1.00; 95% confidence interval CI, 0.93 to 1.09; P = 0.92). Among survivors at 90 days, continued dependence on renal-replacement therapy was confirmed in 85 of 814 patients (10.4%) in the accelerated-strategy group and in 49 of 815 patients (6.0%) in the standard-strategy group (relative risk, 1.74; 95% CI, 1.24 to 2.43). Adverse events occurred in 346 of 1503 patients (23.0%) in the accelerated-strategy group and in 245 of 1489 patients (16.5%) in the standard-strategy group (P<0.001).
Among critically ill patients with acute kidney injury, an accelerated renal-replacement strategy was not associated with a lower risk of death at 90 days than a standard strategy. (Funded by the Canadian Institutes of Health Research and others; STARRT-AKI ClinicalTrials.gov number, NCT02568722.).
Gain-of-Function and Loss-of-Function GABRB3 Variants Lead to Distinct Clinical Phenotypes in Patients With Developmental and Epileptic Encephalopathies
Absalom NL, Liao VW, Johannesen KM, Gardella ...E, Jacobs J, Lesca G, Gokce-Samar Z, Arzimanoglou A, Zeidler S, Striano P, Meyer P, Benkel-Herrenbrueck I, Mero I-L, Rummel J, Chebib M, Møller RS, Ahring PK. Nat Commun. 2022;13(1):1822. doi:10.1038/s41467-022-29280-x
Many patients with developmental and epileptic encephalopathies present with variants in genes coding for GABAA receptors. These variants are presumed to cause loss-of-function receptors leading to reduced neuronal GABAergic activity. Yet, patients with GABAA receptor variants have diverse clinical phenotypes and many are refractory to treatment despite the availability of drugs that enhance GABAergic activity. Here we show that 44 pathogenic GABRB3 missense variants segregate into gain-of-function and loss-of-function groups and respective patients display distinct clinical phenotypes. The gain-of-function cohort (n = 27 patients) presented with a younger age of seizure onset, higher risk of severe intellectual disability, focal seizures at onset, hypotonia, and lower likelihood of seizure freedom in response to treatment. Febrile seizures at onset are exclusive to the loss-of-function cohort (n = 47 patients). Overall, patients with GABRB3 variants that increase GABAergic activity have more severe developmental and epileptic encephalopathies. This paradoxical finding challenges our current understanding of the GABAergic system in epilepsy and how patients should be treated.
Aberrant Neuronal Connectivity in the Cortex Drives Generation of Seizures in Rat Absence Epilepsy
Studer F, Jarre G, Pouyatos B, et al. Brain 2022;145(6):1978-1991. doi:10.1093/brain/awab438.
...Absence epilepsy belongs to genetic epilepsies and is characterized by recurrent generalized seizures that are concomitant with alterations of consciousness and associated with cognitive comorbidities. Little is known about the mechanisms leading to occurrence of epileptic seizures (i.e., epileptogenesis) and, in particular, it remains an open question whether neuronal hypersynchronization, a key feature in seizure initiation, could result from aberrant structural connectivity within neuronal networks endowing them with epileptic properties. In the present study, we addressed this question using a genetic model of absence epilepsy in the rat where seizures initiate in the whisker primary somatosensory cortex. We hypothesized that alterations in structural connectivity of neuronal networks within wS1 contribute to pathological neuronal synchronization responsible for seizures. First, we used rabies virus-mediated retrograde synaptic tracing and evidenced that cortical neurons located in both upper- and deep-layers of whisker primary somatosensory cortex displayed aberrant and significantly increased connectivity the genetic model of absence epilepsy, as highlighted by a higher number of presynaptic partners. Next, we showed at the functional level that disrupting these aberrant whisker primary somatosensory cortex neuronal networks with synchrotron X-ray-mediated cortical microtransections drastically decreased both whisker primary somatosensory cortex neuron synchronization and seizure power, as revealed by in vivo local field potential recordings with multichannel probes. Taken together, our data provide for the first time strong evidence that increased structural connectivity patterns of cortical neurons represent critical pathological substrates for increased neuronal synchronization and generation of absence seizures.
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•Different generalized tonic clonic seizure (GTCS) subtypes occur in various genetic generalized epilepsy syndromes and in individual patients.•At onset, GTCS subtypes activate ...similar brain regions but differ in long-range connectivity.•GTCS evolution to tonic-start epoch associates with reduced long-range connectivity, particularly at δ/θ frequencies.
To determine EEG spatiospectral activation and connectivity in the generalized tonic-clonic seizure (GTCS) semiological subtypes.
39 patients with genetic generalized epilepsy (GGE) who had GTCS (n = 58) during video-EEG monitoring were identified in the Vanderbilt Epilepsy database. GTCSs were classified as absence tonic-clonic, myoclonic tonic-clonic, or tonic-clonic. Patient characteristics and semiological features were compared. Spectral power and node degree, a network measure of connectivity, were calculated at two seizure epochs, electrographic and tonic-start.
Different GTCS subtypes occurred within individual patients. At electrographic-onset, all subtypes activated midline frontal cortex at delta/theta and beta frequencies but differed in network connectivity. In all subtypes, GTCS evolution from electrographic to tonic-start associated with preserved beta frequency spectral power, but reduced connectivity and delta/theta power.
Our findings suggest that at GTCS onset, the subtypes activate similar cortical regions and their different initial semiologies relate to their distinct onset long-range connectivity. Upon transition to the tonic-start epoch, the ictal activity is predominantly conveyed by β frequency activity and connectivity.
Future neurostimulation therapies for medically intractable GTCSs may target the same brain regions for all GTCS subtypes and may be most effective prior to the tonic-start epoch.
Abstract
Background
In critically ill patients with acute kidney injury, renal replacement therapy (RRT) modality and treatment protocols may affect kidney recovery. This study explored whether RRT ...modality and treatment protocol affected RRT dependence in the ‘Randomized Evaluation of Normal versus Augmented Level of RRT’ and the ‘Acute Renal Failure Trial Network’ (ATN) trials.
Methods
Primary outcome was 28-day RRT dependence. Secondary outcomes included RRT dependence among survivors and in different SOFA-based treatment protocol groups. We used the Fine-Gray competing-risk model sub-distribution hazard ratio (SHR) to assess the primary outcome. Analyses were adjusted for confounders.
Results
Of 2542 patients, 2175 (85.5%) received continuous RRT (CRRT) and 367 (14.4%) received intermittent hemodialysis (IHD) as first RRT modality. CRRT-first patients had greater illness severity. After adjustment, there was no between-group difference in 28-day RRT dependence (SHR, 0.96 95% CI 0.84–1.10;
p
= 0.570) or hospital mortality (odds ratio OR, 1.14 95% CI 0.86–1.52;
p
= 0.361) However, among survivors, CRRT-first was associated with decreased 28-day RRT dependence (OR, 0.54 95% CI 0.37–0.80;
p
= 0.002) and more RRT-free days (common OR: 1.38 95% CI 1.11–1.71). Moreover, among CRRT-first patient, the ATN treatment protocol was associated with fewer RRT-free days, greater mortality, and a fourfold increase in RRT dependence at day 28.
Conclusions
There was no difference in RRT dependence at day 28 between IHD and CRRT. However, among survivors and after adjustment, both IHD-first and the ATN treatment protocol were strongly associated with greater risk of RRT dependence at 28 days after randomization.
Trial registration
NCT00221013 registered September 22, 2005, and NCT00076219 registered January 19, 2004.
Objective
Patients with generalized epilepsy exhibit different epileptiform events including asymptomatic interictal spikes (IS), absence seizures with spike‐wave discharges (SWDs), and myoclonic ...seizures (MS). Our objective was to determine the spatiotemporal patterns of cortical activation in SWDs, IS, and MS in the Gabra1+/A322D juvenile myoclonic epilepsy mouse.
Methods
We fabricated affordable, flexible high‐density electroencephalography (HdEEG) arrays and recorded spontaneous SWD, IS, and MS with video/HdEEG. We determined differences among the events in amplitude spectral density (ASD) in the δ/θ/α/β/γ frequency bands at baseline (3.5‐4.0 seconds before the first spike time, t0) and the prespike period (0.1‐0.5 seconds before t0), and we elucidated the spatiotemporal activation during the t0 spike.
Results
All three events had an increase in ASD between baseline and prespike in at least one frequency band. During prespike, MS had the largest δ‐band ASD, but SWD had the greatest α/β/γ band ASD. For all three events, the ASD was largest in the anterior regions. The t0 spike voltage was also greatest in the anterior regions for all three events and IS and MS had larger voltages than SWD. From 7.5 to 17.5 msec after t0, MS had greater voltage than IS and SWD, and maximal voltage was in the posterior parietal region.
Significance
Changes in spectral density from baseline to prespike indicate that none of these generalized events are instantaneous or entirely unpredictable. Prominent engagement of anterior cortical regions during prespike and at t0 suggest that common anterior neural circuits participate in each event. Differences in prespike ASD signify that although the events may engage similar brain regions, they may arise from distinct proictal states with different neuronal activity or connectivity. Prolonged activation of the posterior parietal area in MS suggests that posterior circuits contribute to the myoclonic jerk. Together, these findings identify brain regions and processes that could be specifically targeted for further recording and modulation.
Abstract While epidemiological data suggest a female prevalence in human childhood- and adolescence-onset typical absence epilepsy syndromes, the sex difference is less clear in adult-onset ...syndromes. In addition, although there are more females than males diagnosed with typical absence epilepsy syndromes, there is a paucity of studies on sex differences in seizure frequency and semiology in patients diagnosed with any absence epilepsy syndrome. Moreover, it is unknown if there are sex differences in the prevalence or expression of atypical absence epilepsy syndromes. Surprisingly, most studies of animal models of absence epilepsy either did not investigate sex differences, or failed to find sex-dependent effects. However, various rodent models for atypical syndromes such as the AY9944 model (prepubertal females show a higher incidence than prepubertal males), BN model (also with a higher prevalence in males) and the Gabra1 deletion mouse in the C57BL/6J strain offer unique possibilities for the investigation of the mechanisms involved in sex differences. Although the mechanistic bases for the sex differences in humans or these three models are not yet known, studies of the effects of sex hormones on seizures have offered some possibilities. The sex hormones progesterone, estradiol and testosterone exert diametrically opposite effects in genetic absence epilepsy and pharmacologically-evoked convulsive types of epilepsy models. In addition, acute pharmacological effects of progesterone on absence seizures during proestrus are opposite to those seen during pregnancy. 17β-Estradiol has anti-absence seizure effects, but it is only active in atypical absence models. It is speculated that the pro-absence action of progesterone, and perhaps also the delayed pro-absence action of testosterone, are mediated through the neurosteroid allopregnanolone and its structural and functional homolog, androstanediol. These two steroids increase extrasynaptic thalamic tonic GABAergic inhibition by selectively targeting neurosteroid-selective subunits of GABAA receptors (GABAA Rs). Neurosteroids also modulate the expression of GABAA R containing the γ2, α4, and δ subunits. It is hypothesized that differences in subunit expression during pregnancy and ovarian cycle contribute to the opposite effects of progesterone in these two hormonal states.
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