A Versatile Pipeline for High-fidelity Imaging and Analysis of Vascular Networks Across the Body

Structural and functional changes in vascular networks play a vital role during development, causing or contributing to the pathophysiology of injury and disease. Current methods to trace and image the vasculature in laboratory settings have proven inconsistent, inaccurate, and labor intensive, lacking the inherent three-dimensional structure of vasculature. Here, we provide a robust and highly reproducible method to image and quantify changes in vascular networks down to the capillary level. The method combines vasculature tracing, tissue clearing, and three-dimensional imaging techniques with vessel segmentation using AI-based convolutional reconstruction to rapidly process large, unsectioned tissue specimens throughout the body with high fidelity. The practicality and scalability of our protocol offer application across various fields of biomedical sciences. Obviating the need for sectioning of samples, this method will expedite qualitative and quantitative analyses of vascular networks. Preparation of the fluorescent gel perfusate takes < 30 min per study. Transcardiac perfusion and vasculature tracing takes approximately 20 min, while dissection of tissue samples ranges from 5 to 15 min depending on the tissue of interest. The tissue clearing protocol takes approximately 24-48 h per whole-tissue sample. Lastly, three-dimensional imaging and analysis can be completed in one day. The entire procedure can be carried out by a competent graduate student or experienced technician. Key features • This robust and highly reproducible method allows users to image and quantify changes in vascular networks down to the capillary level. • Three-dimensional imaging techniques with vessel segmentation enable rapid processing of large, unsectioned tissue specimens throughout the body. • It takes approximately 2-3 days for sample preparation, three-dimensional imaging, and analysis. • The user-friendly pipeline can be completed by experienced and non-experienced users.

Chronic spontaneous urticaria: from the hunt for causes and pathogenesis to the identification of different endotypes

Summary

The hunt for the causes and pathogenic mechanisms involved in chronic spontaneous urticaria (CSU) has engaged clinicians and scientists for decades. Although not all aspects of the disease are defined, our knowledge has now improved to the point that we can consider CSU as an umbrella clinical phenotype under which several different endotypes probably exist. The present article will briefly summarize the fascinating history of the progress in our knowledge of this disease.

Flexible, Miniaturized Sensing Probes Inspired by Biofuel Cells for Monitoring Synaptically Released Glutamate in the Mouse Brain

Chemical biomarkers in the central nervous system can provide valuable quantitative measures to gain insight into the etiology and pathogenesis of neurological diseases. Glutamate, one of the most important excitatory neurotransmitters in the brain, has been found to be upregulated in various neurological disorders, such as traumatic brain injury, Alzheimer's disease, stroke, epilepsy, chronic pain, and migraines. However, quantitatively monitoring glutamate release in situ has been challenging. This work presents a novel class of flexible, miniaturized probes inspired by biofuel cells for monitoring synaptically released glutamate in the nervous system. The resulting sensors, with dimensions as low as 50 by 50 μm, can detect real-time changes in glutamate within the biologically relevant concentration range. Experiments exploiting the hippocampal circuit in mice models demonstrate the capability of the sensors in monitoring glutamate release via electrical stimulation using acute brain slices. These advances could aid in basic neuroscience studies and translational engineering, as the sensors provide a diagnostic tool for neurological disorders. Additionally, adapting the biofuel cell design to other neurotransmitters can potentially enable the detailed study of the effect of neurotransmitter dysregulation on neuronal cell signaling pathways and revolutionize neuroscience.

Intravenous continuous home inotropic therapy in advanced heart failure: Insights from an observational retrospective study

INTRODUCTION

Intravenous inotropic support represents an important therapeutic option in advanced heart failure (HF) as bridge to heart transplantation, bridge to mechanical circulatory support, bridge to candidacy or as palliative therapy. Nevertheless, evidence regarding risks and benefits of its use is lacking.

METHODS

we conducted a retrospective single center study, analysing the effect of inotropic therapies in an outpatient cohort, evaluating the burden of hospitalizations, the improvement in quality of life, the incidence of adverse events and the evolution of organ damage.

RESULTS

twenty-seven patients with advanced HF were treated in our Day Hospital service from 2014 to 2021. Nine patients were treated as bridge to heart transplant while eighteen as palliation. Comparing data regarding the year before and after the beginning of inotropic infusion, we observed a reduction of hospitalization (46 vs 25, p<0,001), an improvement of natriuretic peptides, renal and hepatic function since the first month (p<0,001) and a better quality of life in 53% of the population treated. Two hospitalizations for arrhythmias and seven hospitalizations for catheter-related complications were registered.

CONCLUSIONS

in a selected population of advanced HF patients, continuous home inotropic infusion were able to reduce hospitalizations, improving end organ damage and quality of life. We provide a practical guidance on starting and maintaining home inotropic infusion while monitoring a challenging group of patients.

Pheochromocytoma-induced cardiogenic shock: A multicentre analysis of clinical profiles, management and outcomes

OBJECTIVE

There is still uncertainty about the management of patients with pheochromocytoma-induced cardiogenic shock (PICS). This study aims to investigate the clinical presentation, management, and outcome of patients with PICS.

METHODS

We collected, retrospectively, the data of 18 patients without previously known pheochromocytoma admitted to 8 European hospitals with a diagnosis of PICS.

RESULTS

Among the 18 patients with a median age of 50 years (Q1-Q3: 40-61), 50% were men. The main clinical features at presentation were pulmonary congestion (83%) and cyclic fluctuation of hypertension peaks and hypotension (72%). Echocardiography showed a median left ventricular ejection fraction (LVEF) of 25% (Q1-Q3: 15-33.5) with an atypical- Takotsubo (TTS) pattern in 50%. Inotropes/vasopressors were started in all patients and temporary mechanical circulatory support (t-MCS) was required in 11 (61%) patients. All patients underwent surgical removal of the pheochromocytoma; 4 patients (22%) were operated on while under t-MCS. The median LVEF was estimated at 55% at discharge. Only one patient required heart transplantation (5.5%), and all patients were alive at a median follow-up of 679 days.

CONCLUSIONS

PICS should be suspected in case of a CS with severe cyclic blood pressure fluctuation and rapid hemodynamic deterioration, associated with increased inflammatory markers or in case of TTS progressing to CS, particularly if an atypical TTS echocardiographic pattern is revealed. T-MCS should be considered in the most severe cases. The main challenge is to stabilize the patient, with medical therapy or with t-MCS, since it remains a reversible cause of CS with a low mortality rate.

Advanced heart failure: from definitions to therapeutic options

Advanced heart failure (AHF) represents an ominous stage of heart failure (HF), where the expected prognosis remains poor regardless of the improvement in medical knowledge. In this review, we summarize the definition, prognosis, physiopathology, and clinical/therapeutic management of the disease, focusing on the fast and timely referral of the patient to the AHF facilities. We provide an insight of the diagnostic and therapeutic 'work up' performed in an Italian AHF hub, implying a deep phenotypical patients characterization in order to evaluate candidacy to the therapeutic gold standards as heart transplantation (HTx) and left ventricular assist device (LVAD).

Immune checkpoint inhibitor-associated myocarditis: from pathophysiology to rechallenge of therapy - a narrative review

Even if immune checkpoint inhibitors have revolutionized the landscape of cancer therapy, their use may be complicated by immune-related adverse events. Among these, myocarditis is the most severe complication. The clinical suspicion often arises after clinical symptoms onset and increase in cardiac biomarkers or electrocardiographic manifestations. Echocardiography and cardiac magnetic resonance imaging are recommended for each patient. However, since they may be misleadingly normal, endomyocardial biopsy remains the gold standard for establishing the diagnosis. Until now, treatment has been based on glucocorticoids even if increasing interest has risen in other immunosuppressive agents. Although myocarditis currently imposes immunotherapy discontinuation, case reports have suggested a safety rechallenge in low-grade myocarditis paving the way for further studies to respond to this unmet clinical need.

Report of consensus panel 2 from the 11th international workshop on Waldenström's macroglobulinemia on the management of relapsed or refractory WM patients

The consensus panel 2 (CP2) of the 11th International Workshop on Waldenström's macroglobulinemia (IWWM-11) has reviewed and incorporated current data to update the recommendations for treatment approaches in patients with relapsed or refractory WM (RRWM). The key recommendations from IWWM-11 CP2 include: (1) Chemoimmunotherapy (CIT) and/or a covalent Bruton tyrosine kinase (cBTKi) strategies are important options; their use should reflect the prior upfront strategy and are subject to their availability. (2) In selecting treatment, biological age, co-morbidities and fitness are important; nature of relapse, disease phenotype and WM-related complications, patient preferences and hematopoietic reserve are also critical factors while the composition of the BM disease and mutational status (MYD88, CXCR4, TP53) should also be noted. (3) The trigger for initiating treatment in RRWM should utilize knowledge of patients' prior disease characteristics to avoid unnecessary delays. (4) Risk factors for cBTKi related toxicities (cardiovascular dysfunction, bleeding risk and concurrent medication) should be addressed when choosing cBTKi. Mutational status (MYD88, CXCR4) may influence the cBTKi efficacy, and the role of TP53 disruptions requires further study) in the event of cBTKi failure dose intensity could be up titrated subject to toxicities. Options after BTKi failure include CIT with a non-cross-reactive regimen to one previously used CIT, addition of anti-CD20 antibody to BTKi, switching to a newer cBTKi or non-covalent BTKi, proteasome inhibitors, BCL-2 inhibitors, and new anti-CD20 combinations are additional options. Clinical trial participation should be encouraged for all patients with RRWM.

35 years of autologous serum skin test in chronic spontaneous urticaria: what we know and what we do not know

Summary

The autologous serum skin test (ASST) has been used in patients with chronic spontaneous urticaria (CSU) as a means to detect an autoreactivity state for thirty-five years now. Nonetheless, several aspects of this old diagnostic test are still insufficiently defined. Particularly, the nature of the factor(s) responsible for the appearance of the wheal-and-flare skin reaction is still poorly characterized. This article will review our current knowledge about the clinical significance of the ASST and the factors possibly associated with the occurrence of the skin reaction following the intradermal administration of autologous serum that are known so far.

139 INTRAVENOUS CONTINUOUS HOME INOTROPIC THERAPY IN ADVANCED HEART FAILURE - RESULTS AND PRACTICAL GUIDELINES

Background

no firm data exist regarding continuous intravenous inotropic infusion in outpatients with advanced heart failure (AHF).

Methods

We reviewed medical records of all inotrope dependent patients discharged from our institution on continuous home inotropes infusion for AHF after a hospitalization between 2014 and 2021. Indications for inotropic agents included bridge to transplant (BTT) or to candidacy (BTC) strategies or palliative care. We compared the number of hospitalizations the year before and the year after beginning the inotrope continuous infusion, assessing the main hospital diagnosis and the duration of hospital recovery in days, through hospital charts revision. Moreover, we used a linkert 7 item scale to assess quality of life (QoL) and, using peripheral blood sample, we esteemed the end organ damage trend evaluating NTproBNP, creatinine, blood urea nitrogen (BUN) and bilirubin.

Results

From 2014 to 2021, 27 patients (Median age 56 years (Q1-Q3 50-63 years), 74% male and 26% female) were dismissed with continuous inotrope infusion from our institution. The total number of days of hospital stay was 1591 the year before beginning inotropic support (average 58.93 ± 38.70 for patient), significantly different if compared with the post inotropes period (average 22,19 ± 36,84 days for patients, IC 95% 17,488-55,994 p &lt; 0,001). Moreover, the number of hospitalizations per patient fell from 1.93 ± 0.997 to 0,93 ± 0,958 (IC 95% 0,522- 1,478, p &lt; 0,001). After 6 months, 53% of the patients experienced an improvement in quality of life. Regarding end organ damage, while creatinine and BUN showed a significant reduction in the first month, with a trend to stability in the following period, bilirubin and NTproBNP significantly trended to reduction during the 6 month of monitoring.

Conclusions

In a real world population of contemporary AHF, continuous inotropes home infusion documented an improvement in hospitalization, QoL and end organ damage. We offer a practical guideline on initiation, selection and maintenance of chronic inotrope therapy in a population of challenging patients.

108 PHEOCHROMOCYTOMA-INDUCED CARDIOGENIC SHOCK: A MULTICENTRE ANALYSIS OF CLINICAL PROFILES, MANAGEMENT AND OUTCOMES

Aims

There is still uncertainty on the management of patients with pheochromocytoma-induced CS (PICS), as only a few clinical cases have been reported. The aim of this study is to investigate the clinical presentation, management, and outcome of patients with PICS.

Methods

We collected retrospectively 18 patients without previously known pheochromocytoma with histologically proven PICS admitted to 8 European hospitals.

Results

Among the 18 patients with a mean age of 50 years, 50% were men. The main clinical features at presentation were pulmonary congestion (83%) and cyclic fluctuation of hypertension crises and hypotension (72%). On echocardiography, mean left ventricular ejection fraction (LVEF) was 25% with an atypical-Takotsubo pattern (basal/midventricular) in 50%. Laboratory exams showed increased inflammatory markers, in particular, the mean white blood count was 21.9*109/L. Inotropes/vasopressors were started in all patients and a temporary mechanical circulatory support (t-MCS) was required in 11 (61.1%) patients. All patients underwent surgical removal of the pheochromocytoma but 4 (22.2%) on t-MCS. Echocardiogram (16/17 patients) revealed a mean LVEF of 55% at discharge. Only one patient required heart transplantation (5.5%), and all patients were alive at a median follow-up of 679 days.

Conclusions

In patients with PICS, characteristically, an atypical Takotsubo pattern was observed in almost half of the cases. Although the use of exogenous catecholamine can be perceived as deleterious, we showed a fairly good mid-term prognosis with rapid improvement of LVEF in most, even if adrenalectomy often occurred on t-MCS.

Harnessing cortical plasticity via gabapentinoid administration promotes recovery after stroke

Stroke causes devastating sensory-motor deficits and long-term disability due to disruption of descending motor pathways. Restoration of these functions enables independent living and therefore represents a high priority for those afflicted by stroke. Here, we report that daily administration of gabapentin, a clinically approved drug already used to treat various neurological disorders, promotes structural and functional plasticity of the corticospinal pathway after photothrombotic cortical stroke in adult mice. We found that gabapentin administration had no effects on vascular occlusion, haemodynamic changes nor survival of corticospinal neurons within the ipsilateral sensory-motor cortex in the acute stages of stroke. Instead, using a combination of tract tracing, electrical stimulation and functional connectivity mapping, we demonstrated that corticospinal axons originating from the contralateral side of the brain in mice administered gabapentin extend numerous collaterals, form new synaptic contacts and better integrate within spinal circuits that control forelimb muscles. Not only does gabapentin daily administration promote neuroplasticity, but it also dampens maladaptive plasticity by reducing the excitability of spinal motor circuitry. In turn, mice administered gabapentin starting 1 h or 1 day after stroke recovered skilled upper extremity function. Functional recovery persists even after stopping the treatment at 6 weeks following a stroke. Finally, chemogenetic silencing of cortical projections originating from the contralateral side of the brain transiently abrogated recovery in mice administered gabapentin, further supporting the conclusion that gabapentin-dependent reorganization of spared cortical pathways drives functional recovery after stroke. These observations highlight the strong potential for repurposing gabapentinoids as a promising treatment strategy for stroke repair.

Breaking Mental Barriers Promotes Recovery After Spinal Cord Injury

Functional recovery after spinal cord injury (SCI) often proves difficult as physical and mental barriers bar survivors from enacting their designated rehabilitation programs. We recently demonstrated that adult mice administered gabapentinoids, clinically approved drugs prescribed to mitigate chronic neuropathic pain, recovered upper extremity function following cervical SCI. Given that rehabilitative training enhances neuronal plasticity and promotes motor recovery, we hypothesized that the combination of an aerobic-based rehabilitation regimen like treadmill training with gabapentin (GBP) administration will maximize recovery in SCI mice by strengthening synaptic connections along the sensorimotor axis. Whereas mice administered GBP recovered forelimb functions over the course of weeks and months following SCI, no additive forelimb recovery as the result of voluntary treadmill training was noted in these mice. To our surprise, we also failed to find an additive effect in mice administered vehicle. As motivation is crucial in rehabilitation interventions, we scored active engagement toward the rehabilitation protocol and found that mice administered GBP were consistently participating in the rehabilitation program. In contrast, mice administered vehicle exhibited a steep decline in participation, especially at chronic time points. Whereas neuroinflammatory gene expression profiles were comparable between experimental conditions, we discovered that mice administered GBP had increased hippocampal neurogenesis and exhibited less anxiety-like behavior after SCI. We also found that an external, social motivator effectively rescues participation in mice administered vehicle and promotes forelimb recovery after chronic SCI. Thus, not only does a clinically relevant treatment strategy preclude the deterioration of mental health after chronic SCI, but group intervention strategies may prove to be physically and emotionally beneficial for SCI individuals.

Caspase-4/11 exacerbates disease severity in SARS-CoV-2 infection by promoting inflammation and immunothrombosis

Severe acute respiratory syndrome coronavirus 2 (SARS–CoV-2) is a worldwide health concern, and new treatment strategies are needed. Targeting inflammatory innate immunity pathways holds therapeutic promise, but effective molecular targets remain elusive. Here, we show that human caspase-4 (CASP4) and its mouse homolog, caspase-11 (CASP11), are up-regulated in SARS–CoV-2 infections and that CASP4 expression correlates with severity of SARS–CoV-2 infection in humans. SARS–CoV-2–infected Casp11−/− mice were protected from severe weight loss and lung pathology, including blood vessel damage, compared to wild-type (WT) mice and mice lacking the caspase downstream effector gasdermin-D (Gsdmd−/−). Notably, viral titers were similar regardless of CASP11 knockout. Global transcriptomics of SARS–CoV-2–infected WT, Casp11−/−, and Gsdmd−/− lungs identified restrained expression of inflammatory molecules and altered neutrophil gene signatures in Casp11−/− mice. We confirmed that protein levels of inflammatory mediators interleukin (IL)-1β, IL-6, and CXCL1, as well as neutrophil functions, were reduced in Casp11−/− lungs. Additionally, Casp11−/− lungs accumulated less von Willebrand factor, a marker for endothelial damage, but expressed more Kruppel-Like Factor 2, a transcription factor that maintains vascular integrity. Overall, our results demonstrate that CASP4/11 promotes detrimental SARS–CoV-2–induced inflammation and coagulopathy, largely independently of GSDMD, identifying CASP4/11 as a promising drug target for treatment and prevention of severe COVID-19.

C75 PHEOCHROMOCYTOMA–INDUCED CARDIOGENIC SHOCK: A MULTICENTER ANALYSIS OF CLINICAL PROFILES, MANAGEMENT AND OUTCOMES

Background

Pheochromocytoma is a rare neuroendocrine tumor that arises from the adrenal gland and overproduces catecholamines; it is an infrequent cause of cardiogenic shock (CS). Several case reports have investigated pheochromocytoma–induced CS, but larger studies have not yet been carried out.

Objectives

Our work aims to describe a multicenter experience in the diagnosis and management of patients with pheochromocytoma–induced CS, and to raise awareness around this rare condition. Methods: We enrolled all patients with a diagnosis of pheochromocytoma–induced CS admitted to the intensive care units of 8 European referral Hospitals.

Results

Among the 17 patients (47% males, mean age 49,5 years), we found that pulmonary congestion was the mostly represented clinical feature (82%). The most represented echocardiographic left ventricle (LV) pattern was the reverse Takotsubo (TTS) pattern with apical hyperkinesis associated with basal– to mid–ventricular hypokinesis (47%). Elevated systemic vascular resistances (SVR) were observed. Endomyocardial biopsy of the LV was performed in one patient showing contraction band necrosis, oedema and inflammatory reaction. 76% of patients were treated with dobutamine, 70% needed noradrenaline, 29% adrenaline, 23.5% were treated with levosimendan and 17% with milrinone. Mechanical circulatory support devices (MCS) were necessary for 65% of patients. All patients benefited from pheochromocytoma’s surgical excision, with 4 patients operated on while under ECLS. All patients recovered, excepted one (presenting a severe left ventricular dilatation at admission) who required cardiac transplantation.

Conclusion

Pheochromocytoma is an infrequent cause of CS, with most often a TTS–like presentation. It should be suspected in case of a CS with high initial SVR and rapid deterioration. MCS must be considered in the most severe cases. The main challenge is to stabilize the patient, mostly with MCS, since it remains a reversible cause of CS with a low mortality rate. Adrenalectomy can safely be performed even when the patient is under MCS.

Role of comorbidities in heart failure prognosis Part 2: Chronic kidney disease, elevated serum uric acid

Despite improvements in pharmacotherapy, morbidity and mortality rates in community-based populations with chronic heart failure still remain high. The increase in medical complexity among patients with heart failure may be reflected by an increase in concomitant non-cardiovascular comorbidities, which are recognized as independent prognostic factors in this population. Heart failure and chronic kidney disease share many risk factors, and often coexist. The presence of kidney failure is associated with incremented risk of cardiovascular and non-cardiovascular mortality in heart failure patients. Chronic kidney disease is also linked with underutilization of evidence-based heart failure therapy that may reduce morbidity and mortality. More targeted therapies would be important to improve the prognosis of patients with these diseases. In recent years, serum uric acid as a determinant of cardiovascular risk has gained interest. Epidemiological, experimental and clinical data show that patients with hyperuricaemia are at increased risk of cardiac, renal and vascular damage and cardiovascular events. Moreover, elevated serum uric acid predicts worse outcome in both acute and chronic heart failure. While studies have raised the possibility of preventing heart failure through the use of uric acid lowering agents, the literature is still inconclusive on whether the reduction in uric acid will result in a measurable clinical benefit. Available evidences suggest that chronic kidney disease and elevated uric acid could worsen heart failure patients' prognosis. The aim of this review is to analyse a possible utilization of these comorbidities in risk stratification and as a therapeutic target to get a prognostic improvement in heart failure patients.

Gabapentinoid treatment promotes corticospinal plasticity and regeneration following murine spinal cord injury

Axon regeneration failure causes neurological deficits and long-term disability after spinal cord injury (SCI). Here, we found that the α2δ2 subunit of voltage-gated calcium channels negatively regulates axon growth and regeneration of corticospinal neurons, the cells that originate the corticospinal tract. Increased α2δ2 expression in corticospinal neurons contributed to loss of corticospinal regrowth ability during postnatal development and after SCI. In contrast, α2δ2 pharmacological blockade through gabapentin administration promoted corticospinal structural plasticity and regeneration in adulthood. Using an optogenetic strategy combined with in vivo electrophysiological recording, we demonstrated that regenerating corticospinal axons functionally integrate into spinal circuits. Mice administered gabapentin recovered upper extremity function after cervical SCI. Importantly, such recovery relies on reorganization of the corticospinal pathway, as chemogenetic silencing of injured corticospinal neurons transiently abrogated recovery. Thus, targeting α2δ2 with a clinically relevant treatment strategy aids repair of motor circuits after SCI.

Axon growth and synaptic function: A balancing act for axonal regeneration and neuronal circuit formation in CNS trauma and disease

Axons in the adult mammalian central nervous system (CNS) fail to regenerate inside out due to intrinsic and extrinsic neuronal determinants. During CNS development, axon growth, synapse formation, and function are tightly regulated processes allowing immature neurons to effectively grow an axon, navigate toward target areas, form synaptic contacts and become part of information processing networks that control behavior in adulthood. Not only immature neurons are able to precisely control the expression of a plethora of genes necessary for axon extension and pathfinding, synapse formation and function, but also non-neuronal cells such as astrocytes and microglia actively participate in sculpting the nervous system through refinement, consolidation, and elimination of synaptic contacts. Recent evidence indicates that a balancing act between axon regeneration and synaptic function may be crucial for rebuilding functional neuronal circuits after CNS trauma and disease in adulthood. Here, we review the role of classical and new intrinsic and extrinsic neuronal determinants in the context of CNS development, injury, and disease. Moreover, we discuss strategies targeting neuronal and non-neuronal cell behaviors, either alone or in combination, to promote axon regeneration and neuronal circuit formation in adulthood.

Pericytes: Problems and Promises for CNS Repair

Microvascular complications are often associated with slow and progressive damage of various organs. Pericytes are multi-functional mural cells of the microcirculation that control blood flow, vascular permeability and homeostasis. Whereas accumulating evidence suggests that these cells are also implicated in a variety of diseases, pericytes represent promising targets that can be manipulated for therapeutic gain. Here, we review the role of pericytes in angiogenesis, blood-brain barrier (BBB) function, neuroinflammation, tissue fibrosis, axon regeneration failure, and neurodegeneration. In addition, we outline strategies altering pericyte behavior to point out problems and promises for axon regeneration and central nervous system (CNS) repair following injury or disease.

ADF/Cofilin-Mediated Actin Turnover Promotes Axon Regeneration in the Adult CNS

Injured axons fail to regenerate in the adult CNS, which contrasts with their vigorous growth during embryonic development. We explored the potential of re-initiating axon extension after injury by reactivating the molecular mechanisms that drive morphogenetic transformation of neurons during development. Genetic loss- and gain-of-function experiments followed by time-lapse microscopy, in vivo imaging, and whole-mount analysis show that axon regeneration is fueled by elevated actin turnover. Actin depolymerizing factor (ADF)/cofilin controls actin turnover to sustain axon regeneration after spinal cord injury through its actin-severing activity. This pinpoints ADF/cofilin as a key regulator of axon growth competence, irrespective of developmental stage. These findings reveal the central role of actin dynamics regulation in this process and elucidate a core mechanism underlying axon growth after CNS trauma. Thereby, neurons maintain the capacity to stimulate developmental programs during adult life, expanding their potential for plasticity. Thus, actin turnover is a key process for future regenerative interventions.

The Application of Omics Technologies to Study Axon Regeneration and CNS Repair

Traumatic brain and spinal cord injuries cause permanent disability. Although progress has been made in understanding the cellular and molecular mechanisms underlying the pathophysiological changes that affect both structure and function after injury to the brain or spinal cord, there are currently no cures for either condition. This may change with the development and application of multi-layer omics, new sophisticated bioinformatics tools, and cutting-edge imaging techniques. Already, these technical advances, when combined, are revealing an unprecedented number of novel cellular and molecular targets that could be manipulated alone or in combination to repair the injured central nervous system with precision. In this review, we highlight recent advances in applying these new technologies to the study of axon regeneration and rebuilding of injured neural circuitry. We then discuss the challenges ahead to translate results produced by these technologies into clinical application to help improve the lives of individuals who have a brain or spinal cord injury.

Effectiveness of Fludarabine in Advanced B-Cell Chronic Lymphocytic Leukemia

Aims

The study was carried out to investigate the efficacy and toxicity of fludarabine phosphate in the treatment of B-cell chronic lymphocytic leukemia (B-CLL) in previously treated patients.

Methods

Sixteen patients, 11 males and 5 females, 9 in stage B and 7 in stage C, according to the Binet Staging System, were treated with a maximum of 6 cycles of fludarabine (25 mg/m2) for 5 days, every 4 weeks. All patients had been pretreated, 10 were refractory to standard regimens, 5 were in relapse, and 1 patient was in partial remission.

Results

Thirteen patients were judged suitable for evaluation. Overall 9 patients were responsive to treatment; 4 complete and 5 partial responses were observed. Of the 4 patients in complete remission, 3 were alive at 6, 10 and 13 months, respectively, from the beginning of treatment. One patient died after 11 months for acute graft-versus-host disease after allogenic bone marrow transplantation by an HLA sibling donor. Two of the 5 patients in partial remission were alive at 7 and 17 months, respectively, and the other 3 died (2 of disease reexpansion after 14 and 16 months and 1 of septic shock following pneumonia). Four patients were not responsive to treatment: 1 died from disease progression after 8 months from the beginning of therapy, 1 from cardiac failure after 9 months, 1 from septic shock following meningitis, and 1 was alive after 7 months of follow-up. Treatment was well tolerated, with nausea and vomiting in only one patient. We observed two episodes of pneumonitis, without any evidence of the responsible agent, a tumor lysis syndrome with acute renal failure, a recurrence of autoimmune thrombocytopenia, and a Coombs-positive hemolytic anemia.

Conclusions

Fludarabine phosphate is effective in the treatment of patients with advanced B-CLL, even in those refractory to multiple chemotherapy regimens.

Spinal cord injury-induced immunodeficiency is mediated by a sympathetic-neuroendocrine adrenal reflex

Acute spinal cord injury (SCI) causes systemic immunosuppression and life-threatening infections, thought to result from noradrenergic overactivation and excess glucocorticoid release via hypothalamus-pituitary-adrenal axis stimulation. Instead of consecutive hypothalamus-pituitary-adrenal axis activation, we report that acute SCI in mice induced suppression of serum norepinephrine and concomitant increase in cortisol, despite suppressed adrenocorticotropic hormone, indicating primary (adrenal) hypercortisolism. This neurogenic effect was more pronounced after high-thoracic level (Th1) SCI disconnecting adrenal gland innervation, compared with low-thoracic level (Th9) SCI. Prophylactic adrenalectomy completely prevented SCI-induced glucocorticoid excess and lymphocyte depletion but did not prevent pneumonia. When adrenalectomized mice were transplanted with denervated adrenal glands to restore physiologic glucocorticoid levels, the animals were completely protected from pneumonia. These findings identify a maladaptive sympathetic-neuroendocrine adrenal reflex mediating immunosuppression after SCI, implying that therapeutic normalization of the glucocorticoid and catecholamine imbalance in SCI patients could be a strategy to prevent detrimental infections.

Detection of Low-Molecular-Weight Mast Cell-Activating Factors in Serum From Patients With Chronic Spontaneous Urticaria

BACKGROUND AND OBJECTIVES

Functionally active autoantibodies to IgE and to the high-affinity IgE receptor (FcεRI) can be detected in serum in about 40% of patients with chronic spontaneous urticaria (CSU). Recent studies showed that serum from patients with CSU can induce activation of mast cells, irrespective of whether they carry high-affinity IgE receptors. To evaluate mast cell activation induced by factors in the serum of CSU patients with a molecular weight lower than that of autoantibodies.

METHODS

Eight CSU patients and 5 healthy controls were evaluated. Whole serum and serum fractionated at 100, 50, and 30 kDa were used to stimulate in vitro LAD2 mast cells. The enzymatic activity of β-hexosaminidase was evaluated in supernatants and cell pellets as a measure of mast cell degranulation.

RESULTS

Mean (SEM) release of mast cell β-hexosaminidase induced by whole serum from CSU patients was higher than that induced by serum from the healthy controls (14.4 [2.7%] vs 5.1 [2.4%]; P=.027). In addition, serum fractions below 100 kDa and below 50 kDa from CSU patients induced mast cell degranulation that was significantly higher than that induced by the corresponding fractions in sera from healthy controls (10.2% [1.4%] vs 3.8% [1.9%] [P=.024] and 10.1% [1.2%] vs 3.9% [1.7%] [P=.012], respectively). In 4 CSU patients, we evaluated serum fractions <30 kDa, which retained their capacity to activate mast cells (11.0% [0.7%]).

CONCLUSIONS

This study shows that sera from CSU patients may contain low-molecular-weight mast cell-activating factors other than autoantibodies. These factors could be an additional mechanism contributing to the pathogenesis of CSU.