Autocatalytic activation of a malarial egress protease is druggable and requires a protein cofactor.

Malaria parasite egress from host erythrocytes (RBCs) is regulated by discharge of a parasite serine protease called SUB1 into the parasitophorous vacuole (PV). There, SUB1 activates a PV-resident cysteine protease called SERA6, enabling host RBC rupture through SERA6-mediated degradation of the RBC cytoskeleton protein ß-spectrin. Here, we show that the activation of Plasmodium falciparum SERA6 involves a second, autocatalytic step that is triggered by SUB1 cleavage. Unexpectedly, autoproteolytic maturation of SERA6 requires interaction in multimolecular complexes with a distinct PV-located protein cofactor, MSA180, that is itself a SUB1 substrate. Genetic ablation of MSA180 mimics SERA6 disruption, producing a fatal block in ß-spectrin cleavage and RBC rupture. Drug-like inhibitors of SERA6 autoprocessing similarly prevent ß-spectrin cleavage and egress in both P. falciparum and the emerging zoonotic pathogen P. knowlesi. Our results elucidate the egress pathway and identify SERA6 as a target for a new class of antimalarial drugs designed to prevent disease progression.

A malaria parasite phospholipase facilitates efficient asexual blood stage egress.

Malaria parasite release (egress) from host red blood cells involves parasite-mediated membrane poration and rupture, thought to involve membrane-lytic effector molecules such as perforin-like proteins and/or phospholipases. With the aim of identifying these effectors, we disrupted the expression of two Plasmodium falciparum perforin-like proteins simultaneously and showed that they have no essential roles during blood stage egress. Proteomic profiling of parasite proteins discharged into the parasitophorous vacuole (PV) just prior to egress detected the presence in the PV of a lecithin:cholesterol acyltransferase (LCAT; PF3D7_0629300). Conditional ablation of LCAT resulted in abnormal egress and a reduced replication rate. Lipidomic profiles of LCAT-null parasites showed drastic changes in several phosphatidylserine and acylphosphatidylglycerol species during egress. We thus show that, in addition to its previously demonstrated role in liver stage merozoite egress, LCAT is required to facilitate efficient egress in asexual blood stage malaria parasites.

Central venoarterial extracorporeal life support in pediatric refractory septic shock: a single center experience.

OBJECTIVE: Venoarterial extracorporeal membrane oxygenation (VA ECMO) is recognized as a potential support therapy for pediatric patients with refractory septic shock (RSS). This review aims to report our experience with central VA cannulation in pediatric patients with RSS, and to compare this with peripheral VA ECMO cannulations for this condition at our institution. DESIGN: Retrospective case series. SETTING: Pediatric and cardiac intensive care units in an academic pediatric hospital. PATIENTS: All patients 0-18 years old meeting criteria of RSS placed on VA ECMO between January 2011 and December 2018. INTERVENTIONS: None. MEASUREMENTS: Demographics, relevant clinical variables, ECMO run details, and outcomes were collected. RESULTS: Between 2011 and 2018, 14 children were placed on VA ECMO for RSS. Nine were cannulated centrally, with the rest placed on peripheral VA ECMO. Overall survival to hospital discharge was 57.1% (8/14), with 66.7% of the central cannulation cohort surviving versus 40% in the peripheral cannulation (p = 0.34). Median ECMO duration was 147.1 hours (IQR: 91.9-178.6 hours), with survivors having a median length of 147.1 (IQR: 138.5-185.7) versus non survivors 114.7 hours (IQR: 63.7-163.5), p = 0.48. Overall median ICU length of stay (LOS) was 19 days (IQR: 10.5-42.2). The median % maximum flow achieved on VA ECMO was higher in the central cannulation group at 179.6% (IQR: 154.4-188.1) versus the peripheral with 133.5% (98.1-149.1), p = 0.01. Functional status scale (FSS) was used to capture morbidity. All survivors had a mean increase in their FSS from baseline. In the centrally cannulated group, 50% (4/8) received mediastinal exploration, but none developed mediastinitis. In terms of blood product utilization, the central cannulation received more platelets compared to the peripherally cannulated group (median 15.6 vs 3.3 mL/kg/day, p = 0.03). CONCLUSION: A central approach to VA ECMO cannulation is feasible and has potential for good patient outcomes in selected patients.

Outcomes After Extracorporeal Life Support Cannulation in Pediatric Patients With Trisomy 13 and Trisomy 18.

BACKGROUND: Indications for extracorporeal life support (ECLS) have evolved and expanded, yet its use in trisomy 13 (T13) and trisomy 18 (T18) patients remains controversial. We reviewed the experience of the Extracorporeal Life Support Organization with ECLS in these patients to inform practice at our institution. METHODS: The Extracorporeal Life Support Organization registry was queried for all patients younger than 18 y with an International Classification of Diseases, Ninth Edition/Tenth Edition code for T13 or T18 from 2000 to 2018. Basic demographics, ECLS details, and clinical outcomes were recorded. Descriptive statistics were performed. RESULTS: Twenty-eight patients were identified (15 with T13; 13 with T18), representing 0.06% (28 of 46,901) of pediatric ECLS cannulations. The median weight was 3.5 kg (range, 1.4-13), and age at cannulation was 52 d (range, 0 d-6.8 y). Time on ECLS ranged from 13 to 478 h (median, 114). Cardiac defects were diagnosed in 19 (68%) patients, of which 13 (46%) underwent surgical repair. Median oxygenation index pre-ECLS was 45. Venoarterial cannulations accounted for 82% of patients, whereas 14% underwent venovenous cannulation. Overall survival to hospital discharge was 46% with 86% of patients experiencing one or more complications. There were no survivors when cannulation continued past 12 d. CONCLUSIONS: Although complications are frequent, the mortality rate in patients with T13 and T18 remains within the reported range for the general pediatric population. T13 and T18 alone should not be viewed as absolute contraindications to ECLS within the pediatric population but rather considered during the evaluation of a patient's potential candidacy.

A Dinuclear Ruthenium(II) Complex Excited by Near-Infrared Light through Two-Photon Absorption Induces Phototoxicity Deep within Hypoxic Regions of Melanoma Cancer Spheroids.

The dinuclear photo-oxidizing RuII complex [{Ru(TAP2)}2(tpphz)]4+ (TAP = 1,4,5,8- tetraazaphenanthrene, tpphz = tetrapyrido[3,2-a:2',3'-c:3″,2''-h:2‴,3'''-j]phenazine), 14+, is readily taken up by live cells localizing in mitochondria and nuclei. In this study, the two-photon absorption cross section of 14+ is quantified and its use as a two-photon absorbing phototherapeutic is reported. It was confirmed that the complex is readily photoexcited using near-infrared, NIR, and light through two-photon absorption, TPA. In 2-D cell cultures, irradiation with NIR light at low power results in precisely focused phototoxicity effects in which human melanoma cells were killed after 5 min of light exposure. Similar experiments were then carried out in human cancer spheroids that provide a realistic tumor model for the development of therapeutics and phototherapeutics. Using the characteristic emission of the complex as a probe, its uptake into 280 µm spheroids was investigated and confirmed that the spheroid takes up the complex. Notably TPA excitation results in more intense luminescence being observed throughout the depth of the spheroids, although emission intensity still drops off toward the necrotic core. As 14+ can directly photo-oxidize DNA without the mediation of singlet oxygen or other reactive oxygen species, phototoxicity within the deeper, hypoxic layers of the spheroids was also investigated. To quantify the penetration of these phototoxic effects, 14+ was photoexcited through TPA at a power of 60 mW, which was progressively focused in 10 µm steps throughout the entire z-axis of individual spheroids. These experiments revealed that, in irradiated spheroids treated with 14+, acute and rapid photoinduced cell death was observed throughout their depth, including the hypoxic region.

Parasitophorous vacuole poration precedes its rupture and rapid host erythrocyte cytoskeleton collapse in Plasmodium falciparum egress.

In the asexual blood stages of malarial infection, merozoites invade erythrocytes and replicate within a parasitophorous vacuole to form daughter cells that eventually exit (egress) by sequential rupture of the vacuole and erythrocyte membranes. The current model is that PKG, a malarial cGMP-dependent protein kinase, triggers egress, activating malarial proteases and other effectors. Using selective inhibitors of either PKG or cysteine proteases to separately inhibit the sequential steps in membrane perforation, combined with video microscopy, electron tomography, electron energy loss spectroscopy, and soft X-ray tomography of mature intracellular Plasmodium falciparum parasites, we resolve intermediate steps in egress. We show that the parasitophorous vacuole membrane (PVM) is permeabilized 10-30 min before its PKG-triggered breakdown into multilayered vesicles. Just before PVM breakdown, the host red cell undergoes an abrupt, dramatic shape change due to the sudden breakdown of the erythrocyte cytoskeleton, before permeabilization and eventual rupture of the erythrocyte membrane to release the parasites. In contrast to the previous view of PKG-triggered initiation of egress and a gradual dismantling of the host erythrocyte cytoskeleton over the course of schizont development, our findings identify an initial step in egress and show that host cell cytoskeleton breakdown is restricted to a narrow time window within the final stages of egress.

Outcomes of a tertiary-based innovative approach to engage primary care providers in provision of hepatitis C treatment in community settings.

BACKGROUND: Australia is committed to eliminating the hepatitis C virus (HCV) by 2030. Despite regulations in Australia that enable the prescription of subsidised direct acting antiviral (DAA) by primary health care providers, the number of providers who treat patients for HCV remains low and this limits the prospect of HCV elimination. The Prince Charles Hospital, Brisbane, Australia, implemented an innovative program called Cure-It aimed at engaging primary care providers in community-based HCV treatment. This paper aims to describe initial experiences and short-term patient outcomes of this program. METHODS: A formative evaluation was conducted using program data for the period March 2016 to April 2018. Descriptive statistics were used to report the number of engaged primary care providers, patients' baseline characteristics, treatment plans, and treatment outcomes. RESULTS: Thirty primary care providers from different settings were engaged in HCV treatment. Among 331 patients eligible for community-based treatment, 315 (95.2%) commenced treatment, the completion rate was 92.4 and 66.5% achieved sustained virological response at 12 weeks (SVR12). The SVR12 had not been documented for 26.8% of patients. Among patients whose SVR12 was documented, 98.2% achieved SVR12. Only 1.3% of patients experienced treatment failure. CONCLUSION: A flexible tertiary-led model can improve primary care providers and patients' engagement with provision of HCV treatment. Tertiary centres need to play their role to improve the accessibility of HCV treatment through providing training and on-going support for primary care providers while enabling those providers to become more confident in providing treatment independently.

CXCR5-Dependent Entry of CD8 T Cells into Rhesus Macaque B-Cell Follicles Achieved through T-Cell Engineering.

Follicular helper CD4 T cells, TFH, residing in B-cell follicles within secondary lymphoid tissues, are readily infected by AIDS viruses and are a major source of persistent virus despite relative control of viral replication. This persistence is due at least in part to a relative exclusion of effective antiviral CD8 T cells from B-cell follicles. To determine whether CD8 T cells could be engineered to enter B-cell follicles, we genetically modified unselected CD8 T cells to express CXC chemokine receptor 5 (CXCR5), the chemokine receptor implicated in cellular entry into B-cell follicles. Engineered CD8 T cells expressing human CXCR5 (CD8hCXCR5) exhibited ligand-specific signaling and chemotaxis in vitro Six infected rhesus macaques were infused with differentially fluorescent dye-labeled autologous CD8hCXCR5 and untransduced CD8 T cells and necropsied 48 h later. Flow cytometry of both spleen and lymph node samples revealed higher frequencies of CD8hCXCR5 than untransduced cells, consistent with preferential trafficking to B-cell follicle-containing tissues. Confocal fluorescence microscopy of thin-sectioned lymphoid tissues demonstrated strong preferential localization of CD8hCXCR5 T cells within B-cell follicles with only rare cells in extrafollicular locations. CD8hCXCR5 T cells were present throughout the follicles with some observed near infected TFH In contrast, untransduced CD8 T cells were found in the extrafollicular T-cell zone. Our ability to direct localization of unselected CD8 T cells into B-cell follicles using CXCR5 expression provides a strategy to place highly effective virus-specific CD8 T cells into these AIDS virus sanctuaries and potentially suppress residual viral replication.IMPORTANCE AIDS virus persistence in individuals under effective drug therapy or those who spontaneously control viremia remains an obstacle to definitive treatment. Infected follicular helper CD4 T cells, TFH, present inside B-cell follicles represent a major source of this residual virus. While effective CD8 T-cell responses can control viral replication in conjunction with drug therapy or in rare cases spontaneously, most antiviral CD8 T cells do not enter B-cell follicles, and those that do fail to robustly control viral replication in the TFH population. Thus, these sites are a sanctuary and a reservoir for replicating AIDS viruses. Here, we demonstrate that engineering unselected CD8 T cells to express CXCR5, a chemokine receptor on TFH associated with B-cell follicle localization, redirects them into B-cell follicles. These proof of principle results open a pathway for directing engineered antiviral T cells into these viral sanctuaries to help eliminate this source of persistent virus.

Use of venovenous ECMO for neonatal and pediatric ECMO: a decade of experience at a tertiary children's hospital.

BACKGROUND: Advances in extracorporeal membrane oxygenation (ECMO) have led to increased use of venovenous (VV) ECMO in the pediatric population. We present the evolution and experience of pediatric VV ECMO at a tertiary care institution. METHODS: A retrospective cohort study from 01/2005 to 07/2016 was performed, comparing by cannulation mode. Survival to discharge, complications, and decannulation analyses were performed. RESULTS: In total, 160 patients (105 NICU, 55 PICU) required 13 ± 11 days of ECMO. VV cannulation was used primarily in 83 patients with 64% survival, while venoarterial (VA) ECMO was used in 77 patients with 54% survival. Overall, 74% of patients (n = 118) were successfully decannulated; 57% survived to discharge. VA ECMO had a higher rate of intra-cranial hemorrhage than VV (22 vs 9%, p = 0.003). Sixteen VA patients (21%) had radiographic evidence of a cerebral ischemic insult. No cardiac complications occurred with the use of dual-lumen VV cannulas. There were no differences in complications (p = 0.40) or re-operations (p = 0.85) between the VV and VA groups. CONCLUSION: Dual-lumen VV ECMO can be safely performed with appropriate image guidance, is associated with a lower rate of intra-cranial hemorrhage, and may be the preferred first-line mode of ECMO support in appropriately selected NICU and PICU patients. LEVEL OF EVIDENCE: II.

IRAK-1 bypasses priming and directly links TLRs to rapid NLRP3 inflammasome activation.

Pathogenic infections and tissue injuries trigger the assembly of inflammasomes, cytosolic protein complexes that activate caspase-1, leading to cleavage of pro-IL-1ß and pro-IL-18 and to pyroptosis, a proinflammatory cell death program. Although microbial recognition by Toll-like receptors (TLRs) is known to induce the synthesis of the major caspase-1 substrate pro-IL-1ß, the role of TLRs has been considered limited to up-regulation of the inflammasome components. During infection with a virulent microbe, TLRs and nucleotide-binding oligomerization domain-like receptors (NLRs) are likely activated simultaneously. To examine the requirements and outcomes of combined activation, we stimulated TLRs and a specific NLR, nucleotide binding and oligomerization, leucine-rich repeat, pyrin domain-containing 3 (NLRP3), simultaneously and discovered that such activation triggers rapid caspase-1 cleavage, leading to secretion of presynthesized inflammatory molecules and pyroptosis. This acute caspase-1 activation is independent of new protein synthesis and depends on the TLR-signaling molecule IL-1 receptor-associated kinase (IRAK-1) and its kinase activity. Importantly, Listeria monocytogenes induces NLRP3-dependent rapid caspase-1 activation and pyroptosis, both of which are compromised in IRAK-1-deficient macrophages. Our results reveal that simultaneous sensing of microbial ligands and virulence factors by TLRs and NLRP3, respectively, leads to a rapid TLR- and IRAK-1-dependent assembly of the NLRP3 inflammasome complex, and that such activation is important for release of alarmins, pyroptosis, and early IFN-γ production by memory CD8 T cells, all of which could be critical for early host defense.

Bone marrow injection stimulates hepatic ductular reactions in the absence of injury via macrophage-mediated TWEAK signaling.

Tissue progenitor cells are an attractive target for regenerative therapy. In various organs, bone marrow cell (BMC) therapy has shown promising preliminary results, but to date no definite mechanism has been demonstrated to account for the observed benefit in organ regeneration. Tissue injury and regeneration is invariably accompanied by macrophage infiltration, but their influence upon the progenitor cells is incompletely understood, and direct signaling pathways may be obscured by the multiple roles of macrophages during organ injury. We therefore examined a model without injury; a single i.v. injection of unfractionated BMCs in healthy mice. This induced ductular reactions (DRs) in healthy mice. We demonstrate that macrophages within the unfractionated BMCs are responsible for the production of DRs, engrafting in the recipient liver and localizing to the DRs. Engrafted macrophages produce the cytokine TWEAK (TNF-like weak inducer of apoptosis) in situ. We go on to show that recombinant TWEAK activates DRs and that BMC mediated DRs are TWEAK dependent. DRs are accompanied by liver growth, occur in the absence of liver tissue injury and hepatic progenitor cells can be isolated from the livers of mice with DRs. Overall these results reveal a hitherto undescribed mechanism linking macrophage infiltration to DRs in the liver and highlight a rationale for macrophage derived cell therapy in regenerative medicine.

Extubation during pediatric extracorporeal membrane oxygenation: a single-center experience.

OBJECTIVES: Describe aspects of one center's experience extubating infants and children during extracorporeal membrane oxygenation. DESIGN: Retrospective review of medical records. SETTING: Seventy-one-bed critical care service (PICU and cardiovascular ICU) in a large urban tertiary children's hospital. PATIENTS: Pediatric and neonatal patients supported on extracorporeal membrane oxygenation between 1996 and 2013 who were either not intubated or extubated greater than 24 hours during their extracorporeal membrane oxygenation course. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Sixteen of 511 patients on extracorporeal membrane oxygenation were extubated for at least 24 hours during their extracorporeal membrane oxygenation courses. Fourteen had respiratory failure and two had cardiac disease. Five patients died while on extracorporeal membrane oxygenation, but the cause of death was not related to complications associated with extubation. Extubated patients were supported a median of 19.7 days on extracorporeal membrane oxygenation, with a median extubation latency (time between cannulation and first extubation) of 6.2 days and a median extubation duration of 5.5 days. Mean time extubated was 43% of the total time on extracorporeal membrane oxygenation. Two patients were reintubated briefly or had a laryngeal mask airway placed for decannulation (n = 1). The remaining patients were extubated within 5 days of decannulation, weeks afterward (n = 2), transferred to outside facilities (n = 2), or died during extracorporeal membrane oxygenation support (n = 5). We also observed no complications directly attributable to extubation and spontaneous reaeration of consolidated lungs in acute respiratory distress syndrome in extubated patients on extracorporeal membrane oxygenation. CONCLUSION: Extubation and discontinuation of mechanical ventilation appear feasible in patients requiring long-term extracorporeal membrane oxygenation. Emergency procedure planning may need to be modified in extubated patients on extracorporeal membrane oxygenation.

Hepatocellular and extrahepatic cancer risk in people with non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. Much of the recognised health-care burden occurs in the minority of people with NAFLD who progress towards cirrhosis and require specialist follow-up, including risk stratification and hepatocellular carcinoma surveillance. NAFLD is projected to become the leading global cause of cirrhosis and hepatocellular carcinoma, but the frequency of non-cirrhotic hepatocellular carcinoma provides a challenge to existing surveillance strategies. Deaths from extrahepatic cancers far exceed those from hepatocellular carcinoma in NAFLD. Unlike hepatocellular carcinoma, the increased extrahepatic cancer risk in NAFLD is not dependent on liver fibrosis stage. Given that almost 30% of the world's adult population has NAFLD, extrahepatic cancer could represent a substantial health and economic issue. In this Review, we discuss current knowledge and controversies regarding hepatocellular carcinoma risk stratification and surveillance practices in people with NAFLD. We also assess the associations of extrahepatic cancers with NAFLD and their relevance both in the clinic and the wider community.

Joint association of drinking alcohol and obesity in relation to cancer risk: A systematic review and data synthesis.

BACKGROUND: Rates of alcohol consumption and obesity are increasing in many Western populations. For some cancer types, both heavy alcohol consumption and obesity are independently associated with increased risk. Whether combined exposure to both synergistically increases an individual's risk of cancer is unclear. We performed a systematic review to assess whether alcohol and obesity interact to confer higher risk for cancer than the additive sum of their effects. METHODS: A systematic literature search was conducted from the inception date to 13 February 2024 of PubMed, Embase, Cochrane Library and Web of Science to identify studies of alcohol, obesity, and cancer risk. We aimed to undertake a meta-analysis if there were sufficient data. RESULTS: The literature search identified 17,740 potentially eligible studies. After review, 24 studies were included. Eleven reported on the association between alcohol consumption and cancer risk in individuals according to their body mass index (BMI), nine reported on the association between BMI and cancer risk in individuals according to their alcohol consumption, and six studies examined potential synergistic interactions between alcohol consumption and obesity on cancer risk. However, there were insufficient data and significant heterogeneity in the cancers studied to undertake meta-analysis, therefore a systemic review and narrative synthesis was conducted. Overall, there was no consistent pattern of interaction between alcohol use and overweight/obesity on cancer risk across cancer types. CONCLUSIONS: While alcohol and obesity are prevalent and important risk factors for a range of cancers, data are lacking on whether their combined exposure may synergistically increase an individual's risk for cancer. Further study across more cancer types is required to better understand the nature of interactions between alcohol use and obesity on cancer risk.

Colorectal cancer screening participation in First Nations populations worldwide: a systematic review and data synthesis.

Background: First Nations populations have poorer colorectal cancer (CRC) survival compared to non-First Nations populations. Whilst First Nations populations across the world are distinct, shared experiences of discrimination and oppression contribute to persistent health inequities. CRC screening improves survival, however screening rates in First Nations populations are poorly described. This study seeks to define participation rates in CRC screening in First Nations populations worldwide. Methods: A systematic literature search was conducted of PubMed, Embase, Cochrane Library, CINAHL, MEDLINE, grey literature, national registries and ClinicalTrials.gov. All sources were searched from their inception date to 18 February 2024. Studies were included if they reported CRC screening rates in adult (≥18 years) First Nations populations. We aimed to undertake a meta-analysis if there were sufficient data. Quality of papers were assessed using the Joanna Briggs Institute (JBI) appraisal tool. The study was registered with PROSPERO, CRD42020210181. Findings: The literature search identified 1723 potentially eligible published studies. After review, 57 studies were included, 50 from the United States (US), with the remaining studies from Australia, Aotearoa New Zealand (NZ), Canada, Dominica and Guatemala. Additionally, eleven non-indexed reports from national programs in Australia and NZ were included. There were insufficient data to undertake meta-analysis, therefore a systematic review and narrative synthesis were conducted. CRC screening definitions varied, and included stool-based screening, sigmoidoscopy and colonoscopy. US First Nations screening rates ranged between 4.0 and 79.2%, Australia reported 10.6-35.2%, NZ 18.4-49%, Canada 22.4-53.4%, Guatemala 2.2% and Dominica 4.2%. Fifty-five studies were assessed as moderate or high quality and two as low quality. Interpretation: Our findings suggested that there is wide variation in CRC screening participation rates across First Nations populations. Screening data are lacking in direct comparator groups and longitudinal outcomes. Disaggregation of screening data are required to better understand and address First Nations CRC outcome inequities. Funding: None.

Sequential roles for red blood cell binding proteins enable phased commitment to invasion for malaria parasites.

Invasion of red blood cells (RBCs) by Plasmodium merozoites is critical to their continued survival within the host. Two major protein families, the Duffy binding-like proteins (DBPs/EBAs) and the reticulocyte binding like proteins (RBLs/RHs) have been studied extensively in P. falciparum and are hypothesized to have overlapping, but critical roles just prior to host cell entry. The zoonotic malaria parasite, P. knowlesi, has larger invasive merozoites and contains a smaller, less redundant, DBP and RBL repertoire than P. falciparum. One DBP (DBPα) and one RBL, normocyte binding protein Xa (NBPXa) are essential for invasion of human RBCs. Taking advantage of the unique biological features of P. knowlesi and iterative CRISPR-Cas9 genome editing, we determine the precise order of key invasion milestones and demonstrate distinct roles for each family. These distinct roles support a mechanism for phased commitment to invasion and can be targeted synergistically with invasion inhibitory antibodies.

Use of Berlin EXCOR cannulas in both venovenous and venoarterial central extracorporeal membrane oxygenation configurations overcomes the problem of cannula instability while bridging infants and young children to lung transplant.

Objectives: Infants and young children awaiting lung transplantation present challenges that often preclude successful extracorporeal membrane oxygenation support as a bridge to transplantation. Instability of neck cannulas often results in the need for intubation, mechanical ventilation, and muscle relaxation creating a worse transplant candidate. With the use of Berlin Heart EXCOR cannulas (Berlin Heart, Inc) in both venoarterial and venovenous central cannulation configurations, 5 pediatric patients were successfully bridged to lung transplant. Methods: We performed a single-center retrospective case review of central extracorporeal membrane oxygenation cannulation used as a bridge to lung transplantation cases performed at Texas Children's Hospital between 2019 and 2021. Results: Six patients, 2 with pulmonary veno-occlusive disease (15-month-old male and 8-month-old male), 1 with ABCA3 mutation (2-month-old female), 1 with surfactant protein B deficiency (2-month-old female), 1 with pulmonary arterial hypertension in the setting of D-transposition of the great arteries after repair as a neonate (13-year-old male), and 1 with cystic fibrosis and end-stage lung disease, were supported for a median of 56.3 days on extracorporeal membrane oxygenation while awaiting transplantation. All patients were extubated after initiation of extracorporeal membrane oxygenation, participating in rehabilitation until transplant. No complications due to central cannulation and use of the Berlin Heart EXCOR cannulas were observed. One patient with cystic fibrosis developed fungal mediastinitis and osteomyelitis resulting in discontinuation of mechanical support and death. Conclusions: Novel use of Berlin Heart EXCOR cannulas for central cannulation eliminates the problem of cannula instability allowing extubation, rehabilitation, and bridge to lung transplant for infants and young children.

Long-acting lenacapavir protects macaques against intravenous challenge with simian-tropic HIV.

BACKGROUND: Long-acting subcutaneous lenacapavir (LEN), a first-in-class HIV capsid inhibitor approved by the US FDA for the treatment of multidrug-resistant HIV-1 with twice yearly dosing, is under investigation for HIV-1 pre-exposure prophylaxis (PrEP). We previously derived a simian-tropic HIV-1 clone (stHIV-A19) that encodes an HIV-1 capsid and replicates to high titres in pigtail macaques (PTM), resulting in a nonhuman primate model well-suited for evaluating LEN PrEP in vivo. METHODS: Lenacapavir potency against stHIV-A19 in PTM peripheral blood mononuclear cells in vitro was determined and subcutaneous LEN pharmacokinetics were evaluated in naïve PTMs in vivo. To evaluate the protective efficacy of LEN PrEP, naïve PTMs received either a single subcutaneous injection of LEN (25 mg/kg, N = 3) or vehicle (N = 4) 30 days before a high-dose intravenous challenge with stHIV-A19, or 7 daily subcutaneous injections of a 3-drug control PrEP regimen starting 3 days before stHIV-A19 challenge (N = 3). FINDINGS: In vitro, LEN showed potent antiviral activity against stHIV-A19, comparable to its potency against HIV-1. In vivo, subcutaneous LEN displayed sustained plasma drug exposures in PTMs. Following stHIV-A19 challenge, while all vehicle control animals became productively infected, all LEN and 3-drug control PrEP animals were protected from infection. INTERPRETATION: These findings highlight the utility of the stHIV-A19/PTM model and support the clinical development of long-acting LEN for PrEP in humans. FUNDING: Gilead Sciences as part of a Cooperative Research and Development Agreement between Gilead Sciences and Frederick National Lab; federal funds from the National Cancer Institute, National Institutes of Health, under Contract No. 75N91019D00024/HHSN261201500003I; NIH grant R01AI078788.