[Intravesical oxybutynin treatment for neurogenic detrusor overactivity : Efficacy and safety data from clinical practice with the first intravesical oxybutynin treatment authorized in Germany]

Existing therapies for neurogenic detrusor overactivity (NDO), i.e. oral anticholinergics and botulinum toxin injections, can be associated with serious adverse effects or are not always sufficiently effective. Therefore, there is a need for alternative safe and effective treatment options for NDO. Intravesical oxybutynin has been successfully used for several years as a prescription drug in adults and children with spinal cord injury and spina bifida. In 2019, VESOXX® (FARCO-PHARMA, Cologne, Germany) became the first registered intravesical oxybutynin product in Germany, which is indicated for the suppression of neurogenic detrusor overactivity (NDO) in children from 6 years of age and adults, who are managing bladder emptying by clean intermittent catheterisation (CIC), if they cannot be adequately managed by oral anticholinergic treatment due to lack of efficacy and/or intolerable side effects. Overall, there are limited data regarding therapy with intravesical oxybutynin, with the majority of publications being retrospective case series. To date, there are limited data on the efficacy and safety of the newly approved intravesical oxybutynin therapy (VESOXX®) in NDO patients. This noninterventional case series from daily routine treatment which evaluated the physician reports of 38 patients suggests that intravesical oxybutynin effectively improves maximum detrusor pressure (Pdet max) by decreasing it by 59% from 51.94 cm H2O ± 26.12 standard deviation (SD) to 21.07 cm H2O ± 17.32 SD (P < 0.001, n = 34). Maximum bladder pressure (MBC) increased by 34% from 260.45 ml ± 200.26 SD to 348.45 ml ± 175.90 SD. Positive or similar effects compared to previous therapies were seen in bladder morphology, number of incontinence episodes, urinary tract infections and adverse drug effects. This case series demonstrates that intravesical oxybutynin is an important addition to current therapies for the treatment of NDO and it is also efficacious in the rare setting of other underlying diseases beyond spinal cord injury or spina bifida. The approved intravesical oxybutynin preparation VESOXX® may be a useful alternative for patients who do not respond to other therapies or suffered side effects.

Entry of cannabidiol into the fetal, postnatal and adult rat brain

Cannabidiol is a major component of cannabis but without known psychoactive properties. A wide range of properties have been attributed to it, such as anti-inflammatory, analgesic, anti-cancer, anti-seizure and anxiolytic. However, being a fairly new compound in its purified form, little is known about cannabidiol brain entry, especially during development. Sprague Dawley rats at four developmental ages: embryonic day E19, postnatal day P4 and P12 and non-pregnant adult females were administered intraperitoneal cannabidiol at 10 mg/kg with [3H] labelled cannabidiol. To investigate the extent of placental transfer, the drug was injected intravenously into E19 pregnant dams. Levels of [3H]-cannabidiol in blood plasma, cerebrospinal fluid and brain were estimated by liquid scintillation counting. Plasma protein binding of cannabidiol was identified by polyacrylamide gel electrophoresis and its bound and unbound fractions measured by ultrafiltration. Using available RNA-sequencing datasets of E19 rat brain, choroid plexus and placenta, as well as P5 and adult brain and choroid plexus, expression of 13 main cannabidiol receptors was analysed. Results showed that cannabidiol rapidly entered both the developing and adult brains. Entry into CSF was more limited. Its transfer across the placenta was substantially restricted as only about 50% of maternal blood plasma cannabidiol concentration was detected in fetal plasma. Albumin was the main, but not exclusive, cannabidiol binding protein at all ages. Several transcripts for cannabidiol receptors were expressed in age- and tissue-specific manner indicating that cannabidiol may have different functional effects in the fetal compared to adult brain.

Plasma from patients with vaccine-induced immune thrombotic thrombocytopenia displays increased fibrinolytic potential and enhances tissue-type plasminogen activator but not urokinase-mediated plasminogen activation

BACKGROUND

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare complication of adenovirus vector-based COVID-19 vaccines. VITT is associated with markedly raised levels of D-dimer; yet, how VITT modulates the fibrinolytic system is unknown.

OBJECTIVES

We aimed to compare changes in fibrinolytic activity in plasma from patients with VITT, patients diagnosed with venous thromboembolism (VTE) after vaccination but without VITT (VTE-no VITT), and healthy vaccinated controls.

METHODS

Plasma levels of plasmin-antiplasmin (PAP) complexes, plasminogen, and alpha-2-antiplasmin (α2AP) from 10 patients with VITT, 10 patients with VTE-no VITT, and 14 healthy vaccinated controls were evaluated by enzyme-linked immunosorbent assay and/or Western blotting. Fibrinolytic capacity was evaluated by quantitating PAP levels at baseline and after ex vivo plasma stimulation with 50-nM tissue-type plasminogen activator (tPA) or urokinase for 5 minutes.

RESULTS

Baseline PAP complex levels in control and VTE-no VITT individuals were similar but were ∼7-fold higher in plasma from patients with VITT (P < .0001). VITT samples also revealed consumption of α2AP and fibrinogenolysis consistent with a hyperfibrinolytic state. Of interest, VITT plasma produced significantly higher PAP levels after ex vivo treatment with tPA, but not urokinase, compared to the other groups, indicative of increased fibrinolytic potential. This was not due to D-dimer as addition of D-dimer to VTE-no VITT plasma failed to potentiate tPA-induced PAP levels.

CONCLUSION

A marked hyperfibrinolytic state occurs in patients with VITT, evidenced by marked elevations in PAP, α2AP consumption, and fibrinogenolysis. An unidentified plasma cofactor that selectively potentiates tPA-mediated plasminogen activation also appears to exist in the plasma of patients with VITT.

Application of a Radiopaque Viscous Hydrogel Spacer for Prostate Cancer Radiotherapy - A Prospective Multi-Institutional Phase II Study

PURPOSE/OBJECTIVE(S)

Rectal dose can be significantly decreased after spacer application. An initially fluid spacer (FS) spreads in a predetermined space, whereas the positioning of a viscous spacer is determined by needle guidance. The aim of this study was to evaluate the application a radiopaque viscous spacer (RVS) for prostate cancer radiotherapy (RT).

MATERIALS/METHODS

In 30 patients including three centers, 10ml (median) of a RVS was injected between the prostate and anterior rectal wall. The resulting distance and distribution were determined in different planes and compared with a control group of 30 patients with a FS. A cone beam computed tomography (CBCT) was performed at least at the end of RT, a magnetic resonance imaging (MRI) 3 months and 12 months after RT. Injection and treatment tolerability were analyzed.

RESULTS

With a median prostate volume of 40cm3, no overlap was found between planning target volume and rectal volume in most cases (median = 0cm3, interquartile range, IQR 0-0.6cm3). The median contoured RVS before, at the end and 3 months after RT was 8.5cm3, 8.7cm3 und 6.4cm3. Signs of hydrogel migration were not found in any case. Hydrogel visibility in CBCT was rated with "4" on a scale between 1 (poor) and 5 (excellent). Small residues were detected in the MRI 12 months after RT in 3 cases (10%). The median distance between prostate and rectum at the base / midplane / apex was 14mm / 12mm / 11mm. The median rectal volume percentage within the 90% and 80% isodoses was 3.0% (IQR 1.5-4.5%) bzw. 5.9% (IQR 3.0-10.6%). On a scale between 1 (difficult) and 5 (very easy), ease of application was rated with "3-4". Procedure- or device related adverse events have not been observed in any case. Acute and late gastrointestinal toxicities were found in 17% and 3%, respectively (all grade 1). The control of gel distribution of RVS relative to FS was rated with "3-5" on a scale between 1 (much worse) and 5 (much better), the ease of application relative to FS with "2-3" on a scale between 1 (much harder) and 5 (much easier). With a median contoured FS volume of 9.9cm3, the prostate-rectum distance at the base / midplane / apex was 12mm / 10mm / 10mm (significantly smaller in comparison to RVS). However, the lateral gel extension of RVS was smaller in all planes, statistically significant for all comparisons (base: 28mm vs. 34mm, midplane: 28mm vs. 32mm, apex: 21mm vs. 26mm). The gel symmetry (right vs. left) was comparable.

CONCLUSION

The application of a radiopaque viscous hydrogel spacer is harder in comparison to the initially fluid spacer. However, it can be better controlled and is achievable without any complications. Visibility in CBCT is good. The resulting prostate-rectum distance is >10mm in most cases and slightly larger at the base in comparison to FS. The resulting rectum volume within the high dose region and radiotherapy toxicity are very low.

Tranexamic acid in a mouse model of cerebral amyloid angiopathy: setting the stage for a novel stroke treatment approach

Background

Symptomatic intracerebral hemorrhage (sICH) commonly occurs in patients with cerebral amyloid angiopathy (CAA). Amyloid also initiates plasminogen activation and might promote sICH.

Objectives

As amyloid-driven plasmin formation can be blocked by tranexamic acid (TXA), we aimed to evaluate the biodistribution and long-term consequences of TXA on brain amyloid-beta (Aβ) levels, inflammation, and neurologic function in APP/PS1 mice.

Methods

APP/PS1 mice overexpressing the mutant human amyloid precursor protein and wild-type littermates were randomized to TXA (20 mg/mL) or placebo in the drinking water for 6 months. TXA in plasma and various organs was determined by liquid chromatography-mass spectrometry. Plasmin activity assays were performed to evaluate changes in fibrinolytic activity. Neurologic function was evaluated by Y-maze and parallel rod floor testing. Proximity ligation-based immunoassays were used to quantitate changes of 92 biomarkers of inflammation. Brain Aβ levels were assessed by immunohistochemistry.

Results

Long-term oral TXA administration inhibited fibrinolysis. TXA accumulated in the kidney (19.4 ± 11.2 μg/g) with 2- to 5-fold lower levels seen in the lung, spleen, and liver. TXA levels were lowest in the brain (0.28 ± 0.01 μg/g). Over 6 months, TXA had no discernible effect on motor coordination, novelty preference, or brain Aβ levels. TXA reduced plasma levels of epithelial cell adhesion molecule and increased CCL20.

Conclusion

Long-term TXA treatment does not alter brain Aβ levels or impact neurologic behavior in mice predisposed to amyloid deposition and had minor effects on the levels of inflammatory mediators. This finding supports the safety of TXA and lays the foundation for TXA as a novel treatment to reduce sICH in patients with CAA.

Tranexamic acid alters the immunophenotype of phagocytes after lower limb surgery

Background

Tranexamic acid (TXA) is an antifibrinolytic agent frequently used in elective surgery to reduce blood loss. We recently found it also acts as a potent immune-modulator in patients undergoing cardiac surgery.

Methods

Patients undergoing lower limb surgery were enrolled into the “Tranexamic Acid in Lower Limb Arthroplasty” (TALLAS) pilot study. The cellular immune response was characterised longitudinally pre- and post-operatively using full blood examination (FBE) and comprehensive immune cell phenotyping by flowcytometry. Red blood cells and platelets were determined in the FBE and levels of T cell cytokines and the plasmin-antiplasmin complex determined using ELISA.

Results

TXA administration increased the proportion of circulating CD141+ conventional dendritic cells (cDC) on post-operative day (POD) 3. It also reduced the expression of CD83 and TNFR2 on classical monocytes and levels of circulating IL-10 at the end of surgery (EOS) time point, whilst increasing the expression of CCR4 on natural killer (NK) cells at EOS, and reducing TNFR2 on POD-3 on NK cells. Red blood cells and platelets were decreased to a lower extent at POD-1 in the TXA group, representing reduced blood loss.

Conclusion

In this investigation we have extended our examination on the immunomodulatory effects of TXA in surgery by also characterising the end of surgery time point and including B cells and neutrophils in our immune analysis, elucidating new immunophenotypic changes in phagocytes as well as NK cells. This study enhances our understanding of TXA-mediated effects on the haemostatic and immune response in surgery, validating changes in important functional immune cell subsets in orthopaedic patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-022-00373-3.

ECG changes in psychiatric patients on psychotropic medications

Funding Acknowledgements

Type of funding sources: None.

Background

Suicide and euthanasia accounts for 14.3% of deaths in those with psychiatric conditions. The rest are attributed to preventable causes such as cardiovascular disease, respiratory disease, and infections. Several psychotropic medications have been associated with sudden death due to their effect on prolonging QT interval, resulting in the development of a polymorphic ventricular arrhythmia, Torsades de Pointes (TdP). TdP may be self-limiting or lead to sudden cardiac arrest and death.

Purpose

This study aims to evaluate the cardiotoxic effects of psychotropic medications.

Method

This is a descriptive retrospective study of patients submitted to the local psychiatric wards within one year. Patients with psychotropic drug prescriptions were included while patients below 18 years old, pregnant, or did not have ECG performed were excluded. The control group consisted of sex- and age- matched patients with ECG conducted for occupational health purposes. Multiple regression models were conducted to investigate the predictors of significant ECG differences.

Result

Of the 154 psychiatric inpatients admitted, exclusions were 44 patients due to exclusion criteria and 19 patients due to difficulty in physical file access. The study population (n = 91) had a mean age of 36.7 years old with 40.7% female and 59.3% male. The predominant diagnoses were schizophrenia and delusional disorders (58.2%). 86 psychiatric patients (94.5%) were prescribed antipsychotic drugs (APD).

A significantly higher proportion of psychiatric patients has a history of smoking (p &lt; 0.001), alcohol consumption (p = 0.001), and illicit drug use (p &lt; 0.001). They also exhibited significantly more co-morbid illnesses including hypertension (p = 0.022), hyperlipidaemia (p = 0.013), diabetes (p = 0.026) and thyroid disease (p = 0.023) than the control population.

Psychiatric patients had a significantly higher mean heart rate (79.9 vs 69.6 ms; p &lt; 0.001) and QTc interval (452.2 vs 418.6ms; p &lt; 0.001). Mean QTc interval was significantly longer for psychiatric patients in both male (454.2 vs 414.5ms; p &lt; 0.001) and female (449.3 vs 425.6 ms; p = 0.029) gender. Psychotropic drug use is a significant predictor for both prolonged heart rate (p &lt; 0.001) and prolonged QTc interval (p &lt; 0.001). Electrolyte imbalance is a significant predictor of prolonged QTc interval only (p = 0.036). One year follow of both groups detected only 1 psychiatric patient with palpitation.

Conclusion

Psychiatric patients on psychotropic medications have a longer baseline heart rate and QTc interval, which was not associated with MACE at 1 year. None of the underlying comorbidities and lifestyle choices were significant predictors of this. Electrolyte abnormalities and psychotropic drug use significantly predicted QTc prolongation. However, these findings were largely driven by APD use. A follow-up study of a longer period is recommended to investigate whether patients with prolonged QTc interval are of higher risk of MACE occurrence.

Characterisation of Plasma Mitochondrial DNA, MMP-9 and Neutrophil Elastase in Patients Undergoing Coronary Artery Bypass Grafting: Effects of Tranexamic Acid and Postoperative Pneumonia

BACKGROUND

Postoperative pneumonia is a major cause of morbidity and mortality following cardiac surgery. The inflammatory response to cardiac surgery has been widely studied, but specific mechanisms for postoperative pneumonia have not been determined. Tranexamic acid is renowned for its effect on bleeding but can also modulate inflammatory processes. Cardiac surgery is known to release mitochondrial DAMPs (mtDAMPs) and is linked to postoperative inflammation and atrial fibrillation. We speculated that mtDAMPs might be related to postoperative pneumonia and that this might be modulated by tranexamic acid.

METHODS

Forty-one (41) patients from the Aspirin and Tranexamic Acid for Coronary Artery Surgery (ATACAS) trial were studied. Levels of mitochondrial DNA, matrix metallopeptidase 9 (MMP-9) and neutrophil elastase (NE) were determined in plasma preoperatively, at 24 and 72 hours post-surgery and correlated with clinical outcome.

RESULTS

mtDNA was significantly elevated postoperatively in the placebo and tranexamic acid (TXA) groups. Neutrophil elastase increased immediately postoperatively and at 24 hours. MMP-9 was elevated in the placebo group early postoperatively and in the TXA group at the immediate postoperative time point and after 24 hours. Six (6) of the 41 (14.6%) patients subsequently developed pneumonia. mtDNA levels were significantly increased at the early postoperative period and the 24-hour time point in patients with pneumonia.

CONCLUSIONS

Cardiac surgery releases mtDNA, increases MMP-9 and NE and this was not influenced by TXA. Inflammation postoperatively might be linked to pneumonia since mtDNA was further elevated in these patients. Due to the low number of individuals developing pneumonia, further studies are warranted to clearly identify whether TXA impacts on the inflammatory response in postoperative pneumonia.

A systematic review of behaviour analytic interventions for young children with intellectual disabilities

BACKGROUND

According to several comprehensive systematic and narrative reviews, interventions based on applied behaviour analysis principles, or behaviour analytic interventions, are considered evidence based for children with autism spectrum disorder (ASD). However, no comprehensive review of the literature related to behaviour analytic interventions for children with intellectual disability (ID) currently exists.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (registration ID: CRD42018099317), the purpose of this study was to conduct a systematic review of the relevant published literature on the use of behaviour analytic interventions to develop skills in young children (0-8 years) with ID (and without ASD). A preliminary search of the literature identified 1209 potential studies published between January 2000 and April 2020. The review process resulted in 48 articles consisting of 49 studies (i.e. one paper contained two studies) that met the inclusion criteria. Most used single-case research designs. Studies were evaluated on five dimensions of methodological quality based on the Scientific Merit Rating Scale developed by the National Autism Center (NAC). The NAC definitions were also used for the quantity and quality of research evidence required for interventions to be considered established or emerging.

RESULTS

There were a number of limitations to the quality of the body of research. Nevertheless, various behaviour analytic interventions met criteria for being established interventions when used for targeting communication, adaptive and pre-academic skills in young children with ID. Behaviour analytic interventions targeting academic skills met criteria for emerging interventions.

CONCLUSIONS

Although the current literature is limited, results indicate that behaviour analytic interventions may be effectively used to support skill development in children with ID.

Tissue-Type Plasminogen Activator and Tenecteplase-Mediated Increase in Blood Brain Barrier Permeability Involves Cell Intrinsic Complement

Background: Tissue-type plasminogen activator (t-PA) has been the mainstay of therapeutic thrombolysis for patients with acute ischaemic stroke (AIS). However, t-PA can cause devastating intracerebral hemorrhage. t-PA can also influence the CNS in part by modulation of BBB permeability. Complement activation also occurs after AIS and has also been reported to increase BBB permeability. The complement components, C3 and C5, can also be activated by t-PA via plasmin formation and cell intrinsic complement may be involved in this process. Tenecteplase (TNK-tPA) is a t-PA variant with a longer plasma half-life, yet the ability of TNK-tPA to modulate the BBB and complement is less clear.

Aim: To evaluate the effect of C5 and C5a-receptor 1 (C5aR1) inhibitors on t-PA- and TNK-tPA-mediated opening of the BBB.

Methods: We used an in vitro model of the BBB where human brain endothelial cells and human astrocytes were co-cultured on the opposite sides of a porous membrane assembled in transwell inserts. The luminal (endothelial) compartment was stimulated with t-PA or TNK-tPA together with plasminogen, in the presence of PMX205 (a non-competitive C5aR1 antagonist), Avacopan (a competitive C5aR1 antagonist) or Eculizumab (a humanized monoclonal inhibitor of human C5). BBB permeability was assessed 5 and 24 h later. Immunofluorescence was also used to detect changes in C5 and C5aR1 expression in endothelial cells and astrocytes.

Results: PMX205, but not Avacopan or Eculizumab, blocked t-PA-mediated increase in BBB permeability at both the 5 and 24 h time points. PMX205 also blocked TNK-tPA-mediated increase in BBB permeability. Immunofluorescence analysis revealed intracellular staining of C5 in both cell types. C5aR1 expression was also detected on the cell surfaces and also located intracellularly in both cell types.

Conclusion: t-PA and TNK-tPA-mediated increase in BBB permeability involves C5aR1 receptor activation from cell-derived C5a. Selective inhibitors of C5aR1 may have therapeutic potential in AIS.

Plasmin Generation Potential and Recanalization in Acute Ischaemic Stroke; an Observational Cohort Study of Stroke Biobank Samples

Rationale: More than half of patients who receive thrombolysis for acute ischaemic stroke fail to recanalize. Elucidating biological factors which predict recanalization could identify therapeutic targets for increasing thrombolysis success.

Hypothesis: We hypothesize that individual patient plasmin potential, as measured by in vitro response to recombinant tissue-type plasminogen activator (rt-PA), is a biomarker of rt-PA response, and that patients with greater plasmin response are more likely to recanalize early.

Methods: This study will use historical samples from the Barcelona Stroke Thrombolysis Biobank, comprised of 350 pre-thrombolysis plasma samples from ischaemic stroke patients who received serial transcranial-Doppler (TCD) measurements before and after thrombolysis. The plasmin potential of each patient will be measured using the level of plasmin-antiplasmin complex (PAP) generated after in-vitro addition of rt-PA. Levels of antiplasmin, plasminogen, t-PA activity, and PAI-1 activity will also be determined. Association between plasmin potential variables and time to recanalization [assessed on serial TCD using the thrombolysis in brain ischemia (TIBI) score] will be assessed using Cox proportional hazards models, adjusted for potential confounders.

Outcomes: The primary outcome will be time to recanalization detected by TCD (defined as TIBI ≥4). Secondary outcomes will be recanalization within 6-h and recanalization and/or haemorrhagic transformation at 24-h. This analysis will utilize an expanded cohort including ~120 patients from the Targeting Optimal Thrombolysis Outcomes (TOTO) study.

Discussion: If association between proteolytic response to rt-PA and recanalization is confirmed, future clinical treatment may customize thrombolytic therapy to maximize outcomes and minimize adverse effects for individual patients.

Sex-dependent effects of tranexamic acid on blood-brain barrier permeability and the immune response following traumatic brain injury in mice

BACKGROUND

Tranexamic acid (TXA) is an anti-fibrinolytic agent used to reduce bleeding in various conditions including traumatic brain injury (TBI). As the fibrinolytic system also influences the central nervous system and the immune response, TXA may also modulate these parameters following TBI.

OBJECTIVES

To determine the effect of TXA on blood-brain barrier (BBB) integrity and changes in immune and motor function in male and female mice subjected to TBI.

METHODS

Wild-type and plasminogen deficient (plg-/-) mice were subjected to TBI then administered either TXA/vehicle. The degree of BBB breakdown, intracerebral hemorrhage (ICH), motor dysfunction, and changes in inflammatory subsets in blood and brain were determined.

RESULTS AND CONCLUSIONS

Tranexamic acid significantly reduced BBB breakdown, and increased blood neutrophils in male mice 3 hours post-TBI. In contrast, TXA treatment of female mice increased BBB permeability and ICH but had no effect on blood neutrophils at the same time-point. TXA improved motor function in male mice but still increased BBB breakdown in female mice 24 hours post-TBI. Brain urokinase-type plasminogen activator (u-PA) antigen and activity levels were significantly higher in injured females compared to males. Because TXA can promote a pro-fibrinolytic effect via u-PA, these sex differences may be related to brain u-PA levels. TXA also increased monocyte subsets and dendritic cells in the injured brain of wild-type male mice 1 week post-TBI. Plg-/- mice of both sexes had reduced BBB damage and were protected from TBI irrespective of treatment indicating that TXA modulation of the BBB is plasmin-dependent. In conclusion, TXA is protective post-TBI but only in male mice.

Computational modelling for the spiral flow in umbilical arteries with different systole/diastole flow velocity ratios

The systole/diastole (S/D) flow velocity ratios in umbilical arteries (UAs) have been used to assess the health status of the feto-placental circulation, yet its connection to the morphology of UAs, specifically its coiling pattern remains unclear. Spiral flow induces unbalanced wall shear stress (WSS) distribution in UAs, and may contribute to the uneven arterial wall thickness, and the chirality. In this paper, we use a 3D computational fluid dynamics (CFD) technique to quantify the wall shear stress (WSS) in UA models of two configurations, i.e. at 0.17 and 0.50 spirals per centimeter, to represent normo- and hyper-coiling, respectively. For CFD simulations we use two different S/D ratios (3.02 and 5.70) revealed from the ultrasonography waveforms of a normal and an intrauterine growth restriction (IUGR) case. We found that more coils in the UA model enhanced WSS throughout a cardiac cycle (up to 24%) with the same inflow condition. In addition, time-averaged WSS are generally increased and more uneven in the hyper-coiling model. We suggest that the large WSS difference between the peak systole and end diastole (62% higher in the IURG case than the normal case) may induce uneven stenosis distribution at UAs, and contribute to UA chirality.

Extrapolation for a pharmacokinetic model for acetaminophen from adults to neonates: A Latin Hypercube Sampling analysis

Physiological and drug-specific parameters need to be adjusted when extrapolating a pharmacokinetic (PK) model from adults to neonates, so as to reproduce the time profiles of the studied drug(s) consistent with clinical, in vivo data or in vitro cell line measurements. In this paper we present a parameter analysis method, i.e. the Latin Hypercube Sampling (LHS) method for an acetaminophen (APAP) PK model. The original model consists of two compartments (the blood and the urine) with Michaelis-Menten kinetic parameters determined for APAP and its metabolites. The physiological parameters are scaled through allometric laws from adults to neonates, and APAP-specific parameters are adjusted for enzymatic maturational changes. The LHS method is used to statistically investigate the interplay between these parameters. The results for the extrapolated APAP model are consistent with published APAP PK data in neonates. We found the sulphation clearance parameter played a crucial role in the neonatal PK model, but its influence was weakened if the volume of distribution parameters were included. We suggest that this kind of in silico experiment could be valuable as the first step in PK model extrapolation between different ages.

Vertebral Fractures Following Stereotactic Body Radiotherapy for Spine Oligometastases: A Multi-institutional Analysis of Patient Outcomes

AIMS

Stereotactic body radiotherapy (SBRT) is a locally ablative therapy used for the treatment of patients with spine metastases. However, it is associated with higher rates of vertebral compression fractures (VCF) than conventionally fractionated palliative radiotherapy. The purpose of this study was to determine the rate of VCF following spine SBRT and to identify the risk factors associated with this outcome.

MATERIALS AND METHODS

We retrospectively reviewed patients treated at two Australian institutions from January 2015 to March 2019. Descriptive statistics were used to assess patient, tumour and treatment factors. The Log-rank test and Cox proportional hazards model were applied in univariate and multivariable analyses to identify factors associated with VCF, local control and overall survival.

RESULTS

We evaluated 113 spinal segments from 84 patients, with a median follow-up time of 11.9 months. The median dose and fractionation utilised was 30 Gy in three fractions (67.3%), with a single-fraction rate of 0.9%. The median Spinal Instability Neoplastic Score (SINS) of the lesions was 4/18, with most (84.1%) being SINS stable, scoring between 0 and 6. Five VCFs were observed (three progression of pre-existing fractures and two de novo), a cumulative VCF risk of 4.4%. Four of five fractures occurred within the first year after treatment, with a median time to VCF of 9.2 months. A pre-existing VCF (P = 0.011) was associated with subsequent fracture on multivariable analysis, whereas all VCF segments displayed lytic disease appearance. All fractures were managed conservatively with analgesia, without requirement for subsequent surgical intervention.

CONCLUSION

SBRT to spine metastases is safe with respect to VCF, with rates around the lower limit observed in similar studies. Knowledge of factors that predispose to post-treatment fracture, such as pre-existing compression, lytic vertebral disease and SINS >6 will aid in the counselling and selection of patients for this therapy.

Identifying barriers to healthcare delivery and access in the Circumpolar North: important insights for health professionals

Lack of access to healthcare services for people living in the Circumpolar North may have important consequences for their health and well-being, both in terms of the actual treatment and other possible health-related consequences intertwined with their life situation. The aim of the present study was to identify the specific challenges to healthcare service delivery and access for populations in the Circumpolar North that are addressed in contemporary literature. A scoping review of literature published between 2005 and 2016 was conducted and 43 articles were selected for inclusion into the review. The review findings address 4 main themes identified in the literature: (1) the influence of physical geography, (2) healthcare provider-related barriers, (3) the importance of culture and language and (4) the impact of systemic factors. The review of the literature enabled us to identify existing gaps in both health service access and issues discussed in the available literature, particularly for informing healthcare services in the Circumpolar North, as well as point towards opportunities for future research. The thematic findings drawn from interdisciplinary and international literature inform understandings of the impact of health system barriers on healthcare services and the opportunities for Northern residents to support their own health.

A twin study of body mass index and dental caries in childhood

Sub-optimal nutrition and dental caries are both common with significant short and long-term implications for child health and development. We applied twin statistical methods to explore the relationship between body mass index (BMI) and dental caries. We measured BMI at 18 months and six years of age and cumulative dental caries experience at six years in 344 twin children. Dental caries in primary teeth was categorised into ‘any’ or ‘advanced’ and BMI was analysed as both a continuous and categorical variable. Statistical analyses included multiple logistic regression using generalized estimating equations and within/between-pair analyses. There was no association between BMI and ‘any’ dental caries experience at either time-point, neither overall nor in within/between pair analyses. However, ‘advanced’ dental caries at six years was associated with a within-pair difference in BMI of −0.55 kg/m² (95% CI −1.00, −0.11, p = 0.015). A within-pair increase of 1 kg/m² in BMI was associated with a lower within-pair risk of advanced dental caries (OR 0.68, 95% CI 0.52, 0.90, p = 0.007). These findings reveal a possible causal relationship between lower BMI and dental caries. As dental outcomes were only measured at one time point, the direction of this potentially causal relationship is unclear.

An in silico pipeline for subject-specific hemodynamics analysis in liver surgery planning

The progresses in fast simulations of the hepatic flow in subject-specific vascular tree have created new toolkits for pre-surgical planning. The aim of this short communication is to introduce a computational pipeline that integrates several recently developed in silico liver models and algorithms. Firstly, a semi-automatic segmentation pipeline is used to digitise hepatic vessels. Then, a constructive constraint optimisation (CCO) algorithm is used to extend the digitised vascular tree, and also to compute the blood pressure and flow velocity in the tree. Couinaud segments are simulated from the diffusion zones of the portal venous tree. The constructed surgical planning model is then deployed cross-platform for use in various scenarios.

Tranexamic acid modulates the cellular immune profile after traumatic brain injury in mice without hyperfibrinolysis

BACKGROUND

Traumatic brain injury (TBI) is known to promote immunosuppression, making patients more susceptible to infection, yet potentially exerting protective effects by inhibiting central nervous system (CNS) reactivity. Plasmin, the effector protease of the fibrinolytic system, is now recognized for its involvement in modulating immune function.

OBJECTIVE

To evaluate the effects of plasmin and tranexamic acid (TXA) on the immune response in wild-type and plasminogen-deficient (plg-/- ) mice subjected to TBI.

METHODS

Leukocyte subsets in lymph nodes and the brain in mice post TBI were evaluated by flow cytometry and in blood with a hemocytometer. Immune responsiveness to CNS antigens was determined by Enzyme-linked Immunosorbent Spot (ELISpot) assay.  Fibrinolysis was determined by thromboelastography and measuring D-dimer and plasmin-antiplasmin complex levels.

RESULTS

Plg-/-  mice, but not plg+/+  mice displayed increases in both the number and activation of various antigen-presenting cells and T cells in the cLN 1 week post TBI. Wild-type mice treated with TXA also displayed increased cellularity of the cLN 1 week post TBI together with increases in innate and adaptive immune cells. These changes occurred despite the absence of systemic hyperfibrinolysis or coagulopathy in this model of TBI. Importantly, neither plg deficiency nor TXA treatment enhanced the autoreactivity within the CNS.

CONCLUSION

In the absence of systemic hyperfibrinolysis, plasmin deficiency or blockade with TXA increases migration and proliferation of conventional dendritic cells (cDCs) and various antigen-presenting cells and T cells in the draining cervical lymph node (cLN) post TBI. Tranexamic acid might also be clinically beneficial in modulating the inflammatory and immune response after TBI, but without promoting CNS autoreactivity.

Tranexamic Acid Influences the Immune Response, but not Bacterial Clearance in a Model of Post-Traumatic Brain Injury Pneumonia

The antifibrinolytic agent, tranexamic acid (TXA), an inhibitor of plasmin formation, currently is evaluated to reduce bleeding in various conditions, including traumatic brain injury (TBI). Because plasmin is implicated in inflammation and immunity, we investigated the effects of plasmin inhibition on the immune response after TBI in the presence or absence of induced pneumonia. Wild-type mice treated with vehicle or TXA or mice deficient in plasminogen (plg^-/-) underwent TBI using the controlled cortical impact model. Mice were then subjected to Staphylococcus aureus induced pneumonia and the degree of immune competence determined. Significant baseline changes in the innate immune cell profile were seen in plg^-/- mice with increases in spleen weight and white blood cell counts, and elevation in plasma interleukin-6 levels. The plg^-/- mice subjected to TBI displayed no additional changes in these parameters at the 72 h or one week time point post-TBI. The plg^-/- mice subjected to TBI did not exhibit any further increase in susceptibility to endogenous infection. Pneumonia was induced by intratracheal instillation of S. aureus. The TBI did not worsen pneumonia symptoms or delay recovery in plg^-/- mice. Similarly, in wild type mice, treatment with TXA did not impact on the ability of mice to counteract pneumonia after TBI. Administration of TXA after TBI and subsequent pneumonia, however, altered the number and surface marker expression of several myeloid and lymphoid cell populations, consistent with enhanced immune activation at the 72 h time point. This investigation confirms the immune-modulatory properties of TXA, thereby highlighting its effects unrelated to inhibition of fibrinolysis.

Antimicrobial resistance and virulence genes of Streptococcus isolated from dairy cows with mastitis in China

Streptococcus is a major mastitis-causing pathogen in dairy cows. To investigate the prevalence, antimicrobial resistance and virulence gene of Streptococcus in mastitic milk, a total of 735 mastitic raw milk samples from dairy cows in 11 provinces of China were collected and tested. Antimicrobial resistance of Streptococcus isolates was determined by disc diffusion against 8 classes 29 antimicrobial agents, and Streptococcus resistant genes and virulence genes were determined by PCR and agarose gel electrophoresis. A total of 64 (8.71%) isolates of Streptococcus were isolated and identified using biochemical profiling, including 22 isolates of Streptococcus agalactiae, 13 isolates of Streptococcus dysgalactiae, and 29 isolates of Streptococcus uberis. Out of 64 resistant Streptococcus isolates, all isolates (100%) were resistant to 3 or more antimicrobials. The most frequency (n = 18, 28.12%) of the isolates were multi-resistant to 5-7 antimicrobials and the highest multi-resistant number was 29 (n = 1, 1.56%). Streptococcus isolates had the highest resistance rate to tetracycline (98.44%) and oxacillin (98.44%), followed by penicillin G (96.88%) and doxycycline (96.88%), and the lowest resistance was observed with respect to ciprofloxacin (1.56%). A total of 16 antimicrobials resistance genes with 25 combination patterns were detected in the isolates. The gene combination of Sul1/Sul2/Sul3 + gyrA/parC + cat1/cat2 was the most common pattern (12.5%). The correlation between resistant phenotypes and resistance genes in Streptococcs was 35.87%. A total of 7 virulence genes were detected and 59 (92.19%) isolates harbored at least one gene. Twenty-four classes of gene patterns were found in the isolates and the patterns of bca (9.38%) and cfb (9.38%) were the most prevalent form. In conclusion, the issue of drug resistance of Streptococcus is still a great concern in cattle health in China.

t-PA Suppresses the Immune Response and Aggravates Neurological Deficit in a Murine Model of Ischemic Stroke

Introduction: Acute ischemic stroke (AIS) is a potent trigger of immunosuppression, resulting in increased infection risk. While thrombolytic therapy with tissue-type plasminogen activator (t-PA) is still the only pharmacological treatment for AIS, plasmin, the effector protease, has been reported to suppress dendritic cells (DCs), known for their potent antigen-presenting capacity. Accordingly, in the major group of thrombolyzed AIS patients who fail to reanalyze (>60%), t-PA might trigger unintended and potentially harmful immunosuppressive consequences instead of beneficial reperfusion. To test this hypothesis, we performed an exploratory study to investigate the immunomodulatory properties of t-PA treatment in a mouse model of ischemic stroke.

Methods: C57Bl/6J wild-type mice and plasminogen-deficient (plg^−/−) mice were subjected to middle cerebral artery occlusion (MCAo) for 60 min followed by mouse t-PA treatment (0.9 mg/kg) at reperfusion. Behavioral testing was performed 23 h after occlusion, pursued by determination of blood counts and plasma cytokines at 24 h. Spleens and cervical lymph nodes (cLN) were also harvested and characterized by flow cytometry.

Results: MCAo resulted in profound attenuation of immune activation, as anticipated. t-PA treatment not only worsened neurological deficit, but further reduced lymphocyte and monocyte counts in blood, enhanced plasma levels of both IL-10 and TNFα and decreased various conventional DC subsets in the spleen and cLN, consistent with enhanced immunosuppression and systemic inflammation after stroke. Many of these effects were abolished in plg^−/− mice, suggesting plasmin as a key mediator of t-PA-induced immunosuppression.

Conclusion: t-PA, via plasmin generation, may weaken the immune response post-stroke, potentially enhancing infection risk and impairing neurological recovery. Due to the large number of comparisons performed in this study, additional pre-clinical work is required to confirm these significant possibilities. Future studies will also need to ascertain the functional implications of t-PA-mediated immunosuppression for thrombolyzed AIS patients, particularly for those with failed recanalization.

Novel methods for segment-specific blood flow simulation for the liver

One challenge for hepatic flow simulation is to divide the hepatic vasculature into individual Couinaud segments, and to simulate flow at both segmental and organ levels. We propose to integrate a segment simulation algorithm with the flow solver in a Constructive Constraint Optimisation (CCO) algorithm to address this problem. In this way blood flow simulations can be conducted for large segment-specific vasculatures as relevant to surgical procedures. In this short communication we outline the methods and present some preliminary results.

A CT-image based pig atlas model and its potential applications in the meat industry

In this communication we present a novel pig atlas model which is represented by a parametric linear Lagrange or cubic Hermite mesh. The model is developed from data points digitized from a 3D pig CT image. In total 84 muscles and 121 bones are included in the atlas, representing the tissue structures most relevant to the industry. We discuss its potential applications in virtual meat cuts and statistical shape analysis for pig breeding and genetics companies.

011 Ex-vivo generation of plasmin from patients with acute ischaemic stroke is predictive of successful thrombolysis

Introduction

Thrombolysis with recombinant tissue-type plasminogen activator (rt-PA) fails in more than 60% of patients with acute ischaemic stroke (AIS). Simultaneously, there are risks associated with the use of rt-PA, including the risk of symptomatic intracranial haemorrhage (sICH) even in patients who do re-canalise. While thrombus location, aetiology and infarct size can affect the likelihood of successful thrombolysis, other factors distinguishing patients who re-canalise from those who don’t have yet to be fully elucidated. The ability of rt-PA to promote thrombolysis is dependent upon its capacity to generate plasmin, and we set out to test this capacity ex-vivo. We hypothesised that patients with low plasmin generating capacity are less likely to re-canalise following rt-PA treatment.

Methods

Plasma was obtained from 90 AIS patients up to 1 hour before thrombolysis and screened for baseline levels of plasminogen, anti-plasmin, and plasmin-anti-plasmin (PAP) complexes. The degree of inducible plasmin generation was determined using amidolytic assays following ex-vivo addition of rt-PA for 1 hour. ELISA assays were also used to quantitate the fold-increase in PAP complex levels after rt-PA treatment.

Results

rt-PA inducible PAP levels, a surrogate for the capacity to generate plasmin from plasminogen, varied dramatically between patients. The ratio of post-thrombolysis PAP to pre-thrombolysis PAP ranged from 3.4 to 105.9 within the cohort examined for this study. Multivariate regression analyses revealed that each fold increase in PAP levels was associated with a 4.2% increase in the odds of recanalisation (p=0,035) when corrected for blood glucose levels.

Conclusion

This is the first report of ex vivo-inducible plasmin generation as a predictor of thrombolysis. The predictive power of this screening assay for sICH is still under investigation.

LDL receptor blockade reduces mortality in a mouse model of ischaemic stroke without improving tissue-type plasminogen activator-induced brain haemorrhage: towards pre-clinical simulation of symptomatic ICH

Background

Symptomatic intracerebral haemorrhage (sICH) following tissue-type plasminogen activator (rt-PA) administration is the most feared and lethal complication of thrombolytic therapy for ischaemic stroke, creating a significant obstacle for a broader uptake of this beneficial treatment. rt-PA also undermines cerebral vasculature stability in a multimodal process which involves engagement with LDL receptor-related protein 1 (LRP-1), potentially underlying the development of sICH.

Aims and methods

We aimed to simulate rt-PA-induced haemorrhagic transformation (HT) in a mouse model of stroke and to assess if it drives symptomatic neurological deterioration and whether it is attenuated by LDL receptor blockade. rt-PA (10 mg/kg) or its vehicle, with or without the LDL receptor antagonist, receptor-associated protein (RAP; 2 mg/kg), were intravenously injected at reperfusion after 0.5 or 4 h of middle cerebral artery occlusion (MCAo). Albumin and haemoglobin content were measured in the perfused mouse brains 24 h post MCAo as indications of blood–brain barrier (BBB) compromise and HT, respectively.

Results

rt-PA did not elevate brain albumin and haemoglobin levels in sham mice or in mice subjected to 0.5 h MCAo. In contrast, administration of rt-PA after prolonged MCAo (4 h) caused a marked increase in HT (but similar changes in brain albumin) compared to vehicle, mimicking the clinical shift from a safe to detrimental intervention. Interestingly, this HT did not correlate with functional deficit severity at 24 h, suggesting that it does not play a symptomatic role in our mouse stroke model. Co-administration of RAP with or without rt-PA reduced mortality and neurological scores but did not effectively decrease brain albumin and haemoglobin levels.

Conclusion

Despite the proven causative relationship between severe HT and neurological deterioration in human stroke, rt-PA-triggered HT in mouse MCAo does not contribute to neurological deficit or simulate sICH. Model limitations, such as the long duration of occlusion required, the type of HT achieved and the timing of deficit assessment may account for this mismatch. Our results further suggest that blockade of LDL receptors improves stroke outcome irrespective of rt-PA, blood–brain barrier breakdown and HT.