Cellular Senescence Contributes to the Progression of Hyperoxic Bronchopulmonary Dysplasia.

Oxidative stress, inflammation, and endoplasmic reticulum (ER) stress sequentially occur in bronchopulmonary dysplasia (BPD), and all result in DNA damage. When DNA damage becomes irreparable, tumor suppressors increase, followed by apoptosis or senescence. Although cellular senescence contributes to wound healing, its persistence inhibits growth. Therefore, we hypothesized that cellular senescence contributes to BPD progression. Human autopsy lungs were obtained. Sprague-Dawley rat pups exposed to 95% oxygen between Postnatal Day 1 (P1) and P10 were used as the BPD phenotype. N-acetyl-lysyltyrosylcysteine-amide (KYC), tauroursodeoxycholic acid (TUDCA), and Foxo4 dri were administered intraperitoneally to mitigate myeloperoxidase oxidant generation, ER stress, and cellular senescence, respectively. Lungs were examined by histology, transcriptomics, and immunoblotting. Cellular senescence increased in rat and human BPD lungs, as evidenced by increased oxidative DNA damage, tumor suppressors, GL-13 stain, and inflammatory cytokines with decreased cell proliferation and lamin B expression. Cellular senescence-related transcripts in BPD rat lungs were enriched at P10 and P21. Single-cell RNA sequencing showed increased cellular senescence in several cell types, including type 2 alveolar cells. In addition, Foxo4-p53 binding increased in BPD rat lungs. Daily TUDCA or KYC, administered intraperitoneally, effectively decreased cellular senescence, improved alveolar complexity, and partially maintained the numbers of type 2 alveolar cells. Foxo4 dri administered at P4, P6, P8, and P10 led to outcomes similar to TUDCA and KYC. Our data suggest that cellular senescence plays an essential role in BPD after initial inducement by hyperoxia. Reducing myeloperoxidase toxic oxidant production, ER stress, and attenuating cellular senescence are potential therapeutic strategies for halting BPD progression.

A safety and feasibility trial of 131 I-MIBG in newly diagnosed high-risk neuroblastoma: A Children's Oncology Group study.

INTRODUCTION: 131 I-meta-iodobenzylguanidine (131 I-MIBG) is effective in relapsed neuroblastoma. The Children's Oncology Group (COG) conducted a pilot study (NCT01175356) to assess tolerability and feasibility of induction chemotherapy followed by 131 I- MIBG therapy and myeloablative busulfan/melphalan (Bu/Mel) in patients with newly diagnosed high-risk neuroblastoma. METHODS: Patients with MIBG-avid high-risk neuroblastoma were eligible. After the first two patients to receive protocol therapy developed severe sinusoidal obstruction syndrome (SOS), the trial was re-designed to include an 131 I-MIBG dose escalation (12, 15, and 18 mCi/kg), with a required 10-week gap before Bu/Mel administration. Patients who completed induction chemotherapy were evaluable for assessment of 131 I-MIBG feasibility; those who completed 131 I-MIBG therapy were evaluable for assessment of 131 I-MIBG + Bu/Mel feasibility. RESULTS: Fifty-nine of 68 patients (86.8%) who completed induction chemotherapy received 131 I-MIBG. Thirty-seven of 45 patients (82.2%) evaluable for 131 I-MIBG + Bu/Mel received this combination. Among those who received 131 I-MIBG after revision of the study design, one patient per dose level developed severe SOS. Rates of moderate to severe SOS at 12, 15, and 18 mCi/kg were 33.3%, 23.5%, and 25.0%, respectively. There was one toxic death. The 131 I-MIBG and 131 I-MIBG+Bu/Mel feasibility rates at the 15 mCi/kg dose level designated for further study were 96.7% (95% CI: 83.3%-99.4%) and 81.0% (95% CI: 60.0%-92.3%). CONCLUSION: This pilot trial demonstrated feasibility and tolerability of administering 131 I-MIBG followed by myeloablative therapy with Bu/Mel to newly diagnosed children with high-risk neuroblastoma in a cooperative group setting, laying the groundwork for a cooperative randomized trial (NCT03126916) testing the addition of 131 I-MIBG during induction therapy.

COVID-19 pre-procedural testing strategy and early outcomes at a large tertiary care children's hospital.

PURPOSE: With the emergence of the coronavirus disease-2019 (COVID-19) pandemic, institutions were tasked with developing individualized pre-procedural testing strategies that allowed for re-initiation of elective procedures within national and state guidelines. This report describes the experience of a single US children's hospital (Children's Wisconsin, CW) in developing a universal pre-procedural COVID-19 testing protocol and reports early outcomes. METHODS: The CW pre-procedural COVID-19 response began with the creation of a multi-disciplinary taskforce that sought to develop a strategy for universal pre-procedural COVID-19 testing which (1) maximized patient safety, (2) prevented in-hospital viral transmission, (3) conserved resources, and (4) allowed for resumption of procedural care within institutional capacity. RESULTS: Of 11,209 general anesthetics performed at CW from March 16, 2020 to October 31, 2020, 11,150 patients (99.5%) underwent pre-procedural COVID-19 testing. Overall, 1.4% of pre-procedural patients tested positive for COVID-19. By June 2020, CW was operating at near-normal procedural volume and there were no documented cases of in-hospital viral transmission. Only 0.5% of procedures were performed under augmented COVID-19 precautions (negative pressure environment and highest-level personal protective equipment). CONCLUSION: CW successfully developed a multi-disciplinary pre-procedural COVID-19 testing protocol that enabled resumption of near-normal procedural volume within three months while limiting in-hospital viral transmission and resource use.

Pleuropulmonary blastoma-like peritoneal sarcoma: a newly described malignancy associated with biallelic DICER1 pathogenic variation.

Since the original description of pathogenic germline DICER1 variation underlying pleuropulmonary blastoma (PPB), the spectrum of extrapulmonary neoplasms known to be associated with DICER1 has continued to expand and now includes tumors of the ovary, thyroid, kidney, eye, and brain among other sites. This report documents our experience with another manifestation: a primitive sarcoma that resembles PPB and DICER1-associated sarcoma of the kidney. These tumors are distinguished by their unusual location in the peritoneal cavity, associated with visceral and/or parietal mesothelium. A total of seven cases were identified through pathology review in children presenting at a median age of 13 years (range 3-14 years). Primary sites of origin included the fallopian tube (four cases), serosal surface of the colon (one case), and pelvic sidewall (two cases). One case had pathologic features of type I PPB, another type Ir (regressed) PPB, and the remaining five had features of type II or III PPB with a mixed primitive sarcomatous pattern with or without cystic elements. All had a pathogenic DICER1 variation identified in germline and/or tumor DNA. PPB-like peritoneal tumors represent a newly described manifestation of DICER1 pathogenic variation whose pathologic features are also recapitulated in DICER1-related renal sarcoma, cervical embryonal rhabdomyosarcoma, and some Sertoli-Leydig cell tumors with heterologous elements. Tumors arising from the fallopian tube or elsewhere in the abdomen/pelvis, especially those with heterogeneous rhabdomyosarcomatous and/or cartilaginous differentiation, should prompt consideration of germline and tumor DICER1 testing.

Attenuation of Helper T Cell Capacity for TH1 and TH17 Differentiation in Children With Nontuberculous Mycobacterial Infection.

Nontuberculous mycobacteria (NTM) infect children with increasing frequency worldwide. Using blood and lymph node tissue from children with NTM lymphadenitis, and uninfected lymph node tissue from community controls, we evaluated helper T (TH) cells in functional assays of TH1/TH17 differentiation and measured the concentration of their associated cytokines at the site of infection. Circulating TH cells from infected children were attenuated in their TH1/TH17 differentiation capacity and expressed less interferon γ and interleukin 17 after polyclonal stimulation. Similar differences were observed at the site of infection, where most cytokine concentrations were unchanged relative to controls. Our data are consistent with a model wherein TH1/TH17 differentiation is attenuated in NTM-infected children.

Adequacy and Accuracy of Core Biopsy in Children: A Radiologic/Pathologic Correlation Study.

Core biopsy (CB) is increasingly popular for assessing solid lesions in children. To date, pediatric literature is limited regarding factors contributing to diagnostically inadequate or inaccurate CB. Therefore, we retrospectively examined radiologic/pathologic factors associated with adequacy/accuracy of CB in pediatric patients. A search of the surgical pathology database for CB between January 2007 and December 2014 yielded 134 CB from 99 patients. Age, sex, anatomic site of lesion, CB diagnosis, and final diagnosis were acquired from the electronic medical record. Image guidance modality, lesion size, and CB sampling device were obtained from radiology records. CB hematoxylin and eosin slides were reviewed for fragmentation, percentage of fibrosis, and percentage of necrosis. Overall, CB length was measured using cellSens software and a DP71 camera. Groups were compared using 2-sided homoscedastic Student's t tests; 87.3% (117/134) CB were diagnostic; final diagnosis was available for 105 cases, with a concordance rate of 80.0% (84/105). Image guidance modality, lesion site (extremity vs nonextremity), and CB needle gauge did not significantly differ between diagnostic versus nondiagnostic CB or concordant versus discordant CB. Diagnostic CB had less necrosis and fibrosis than did nondiagnostic CBs (6.8% vs 29.7%, P = .0002 and 10.3% vs 29.1%, P = .0006). Nondiagnostic and discordant CB were more likely to be from bony lesions than soft tissue ( P = .01 and P = .0248). CB is valuable for diagnosing solid lesions in children, with good overall diagnostic rates regardless of lesion size, location, or imaging modality used for biopsy. Nondiagnostic and discordant CB were more often obtained from bony lesions; sampling via open biopsy may be more useful in that setting. Nondiagnostic and discordant CB have more necrosis and fibrosis, suggesting that on-site evaluation of CB tissue viability-for example, by touch imprint or fine needle aspiration-may be useful in further enhancing CB utility.

Pediatric renal and genitourinary tract tumors and the contributions of Dr. Louis "Pepper" Dehner therewith.

Dr. Louis "Pepper" Dehner is an internationally renowned surgical pathologist, especially in the subspecialty of pediatric pathology. Although his clinical and academic expertise are broad, with over 400 published articles, some of his most intriguing contributions have been in the area of pediatric renal and genitourinary pathology. This review focuses on the entities in these following organ systems where he has focused his efforts: malignant rhabdoid tumor, renal medullary carcinoma, Ewing sarcoma/peripheral neuroectodermal tumor, and the DICER1-related lesions cystic nephroma, embryonal rhabdomyosarcoma of the uterine cervix, and Sertoli-Leydig cell tumor.

Peripheral neuroblastic tumors with genotype-phenotype discordance: a report from the Children's Oncology Group and the International Neuroblastoma Pathology Committee.

BACKGROUND: Of 4,706 peripheral neuroblastic tumors (pNTs) registered on the Children's Cancer Group and Children's Oncology Group Neuroblastoma Study between 1989 and 2010, 51 cases (1.1%) had genotype-phenotype discordance characterized by MYCN amplification (indicating poor prognosis) and Favorable Histology (indicating better prognosis). PROCEDURE: To distinguish prognostic subgroups in the genotype-phenotype discordant pNTs, two subgroups, "conventional" and "bull's eye," were identified based on the nuclear morphology. The "conventional" tumors (35 cases) included: Neuroblastoma, poorly differentiated subtype (NB-PD, 26 cases) with "salt-and-pepper" nuclei; neuroblastoma, differentiating subtype (4 cases); ganglioneuroblastoma, intermixed (3 cases); and ganglioneuroma, maturing subtype (2 cases). The "bull's eye" tumors included NB-PD with prominent nucleoli (16 cases). Clinicopathologic characteristics of these two subgroups were analyzed. N-myc protein expression was tested immunohistochemically on available tumors. RESULTS: No significant difference was found between these two subgroups in the distribution of prognostic factors such as age at diagnosis, clinical stage, histopathology category/subtype, mitosis-karyorrhexis index, ploidy, 1p LOH, and unbalanced 11q LOH. However, prognosis of the patients with "conventional" tumors (5-year EFS 85.7 ± 12.2%; OS 89.3 ± 10.3%) was significantly better than those with "bull's eye" tumors (EFS 31.3 ± 13.0%; OS 42.9 ± 16.2%; P = 0.0010 and 0.0008, respectively). Immunohistochemically all (11/11) tested "conventional" tumors were negative, and 10/11 tested "bull's eye" tumors were positive for N-myc protein expression. CONCLUSIONS: Based on the presence or absence of prominent nucleoli (the putative site of RNA synthesis/accumulation leading to N-myc protein expression), two prognostic subgroups, "conventional" with a better prognosis and "bull's eye" with a poor prognosis, were distinguished among the genotype-phenotype discordant pNTs.

Analytical validation and implementation of a pan cancer next-generation sequencing panel, CANSeqTMKids for molecular profiling of childhood malignancies.

Next-Generation Sequencing (NGS) allows rapid analysis of multiple genes for the detection of clinically actionable variants. This study reports the analytical validation of a targeted pan cancer NGS panel CANSeqTMKids for molecular profiling of childhood malignancies. Analytical validation included DNA and RNA extracted from de-identified clinical specimens including formalin fixed paraffin embedded (FFPE) tissue, bone marrow and whole blood as well as commercially available reference materials. The DNA component of the panel evaluates 130 genes for the detection of single nucleotide variants (SNVs), Insertion and Deletions (INDELs), and 91 genes for fusion variants associated with childhood malignancies. Conditions were optimized to use as low as 20% neoplastic content with 5 ng of nucleic acid input. Evaluation of the data determined greater than 99% accuracy, sensitivity, repeatability, and reproducibility. The limit of detection was established to be 5% allele fraction for SNVs and INDELs, 5 copies for gene amplifications and 1,100 reads for gene fusions. Assay efficiency was improved by automation of library preparation. In conclusion, the CANSeqTMKids allows for the comprehensive molecular profiling of childhood malignancies from different specimen sources with high quality and fast turnaround time.

Clinical utility of whole-genome DNA methylation profiling as a primary molecular diagnostic assay for central nervous system tumors-A prospective study and guidelines for clinical testing.

Background: Central nervous system (CNS) cancer is the 10th leading cause of cancer-associated deaths for adults, but the leading cause in pediatric patients and young adults. The variety and complexity of histologic subtypes can lead to diagnostic errors. DNA methylation is an epigenetic modification that provides a tumor type-specific signature that can be used for diagnosis. Methods: We performed a prospective study using DNA methylation analysis as a primary diagnostic method for 1921 brain tumors. All tumors received a pathology diagnosis and profiling by whole genome DNA methylation, followed by next-generation DNA and RNA sequencing. Results were stratified by concordance between DNA methylation and histopathology, establishing diagnostic utility. Results: Of the 1602 cases with a World Health Organization histologic diagnosis, DNA methylation identified a diagnostic mismatch in 225 cases (14%), 78 cases (5%) did not classify with any class, and in an additional 110 (7%) cases DNA methylation confirmed the diagnosis and provided prognostic information. Of 319 cases carrying 195 different descriptive histologic diagnoses, DNA methylation provided a definitive diagnosis in 273 (86%) cases, separated them into 55 methylation classes, and changed the grading in 58 (18%) cases. Conclusions: DNA methylation analysis is a robust method to diagnose primary CNS tumors, improving diagnostic accuracy, decreasing diagnostic errors and inconclusive diagnoses, and providing prognostic subclassification. This study provides a framework for inclusion of DNA methylation profiling as a primary molecular diagnostic test into professional guidelines for CNS tumors. The benefits include increased diagnostic accuracy, improved patient management, and refinements in clinical trial design.

Embryonal rhabdomyosarcoma of the uterine cervix: a report of 14 cases and a discussion of its unusual clinicopathological associations.

Embryonal rhabdomyosarcoma of the uterine cervix is an uncommon presentation of the most common soft-tissue sarcoma in the first decades of life. Unlike embryonal rhabdomyosarcoma in other anatomic sites, in which 70-80% of cases present before 9 years of age, the average age in our series of 14 cervical cases was 12.4 years (median, 13 years), with an age range of 9 months to 32 years at diagnosis. Of the 14 cases, 12 presented as a polyp at the cervical os; two patients had an infiltrative mass in the cervix without a botryoid polyp. The polyps measured 1.5-5 cm and all had the histopathological pattern of the sarcoma botryoides variant of embryonal rhabdomyosarcoma, with condensations of primitive and differentiated rhabdomyoblasts beneath the surface epithelium and around endocervical glands. Nodules of benign-appearing cartilage were present in the stroma of six cases (43%). One of the embyronal rhabdomyosarcomas from the youngest patient, 9 months old, also had a distinctive microscopic focus of immature tubular profiles in a primitive stroma; these tubules expressed epithelial and neuroendocrine markers. Two patients had a pleuropulmonary blastoma, one diagnosed 9 years before the embryonal rhabdomyosarcoma of the cervix and the other recognized synchronously. This latter 9-year old had a DICER1 germline mutation. One patient presented with hirsutism and had a Sertoli-Leydig cell tumor, an incidentally detected cervical embryonal rhabdomyosarcoma, and nodular hyperplasia of the thyroid. Although a pleuropulmonary blastoma was not documented in the latter patient, ovarian sex-cord stromal tumors and nodular hyperplasia of the thyroid are manifestations of the pleuropulmonary blastoma family tumor and dysplasia syndrome (OMIM 601200). Embryonal rhabdomyosarcoma of the cervix must be distinguished from other rare entities, including adenosarcoma, malignant mixed Mullerian tumor and low-grade stromal sarcoma, as the former has a better prognosis; 12 of our 14 patients remain disease-free following conservative surgery and chemotherapy. Our study suggests that cervical embryonal rhabdomyosarcoma may be another pathological manifestation in the spectrum of extrapulmonary pathology in the setting of pleuropulmonary blastoma.

DICER1 mutations in embryonal rhabdomyosarcomas from children with and without familial PPB-tumor predisposition syndrome.

Embryonal rhabdomyosarcoma (ERMS) is the most common childhood sarcoma and is a component of the familial pleuropulmonary blastoma (PPB)-predisposition syndrome. Using the PPB model, we hypothesized that DICER1 mutations would be found in familial and sporadic forms of ERMS. Blood samples from four children with familial PPB and ERMS, and 52 sporadic ERMS tumors were tested for DICER1 mutations. Germline DICER1 mutations were found in all four patients with familial PPB and 2 of 52 (3.8%) sporadic ERMS had somatic mutations. Our findings confirm the pathogenetic relationship between ERMS and PPB suggesting that ERMS may result from abnormal miRNA regulation.

Epithelioid osteoblastoma. Clinicopathologic and immunohistochemical study of 17 cases.

Seventeen cases of epithelioid osteoblastoma were reviewed. The tumors most commonly arose from the vertebrae (7 cases), followed by the mandible (3), sacrum (2), bones of the foot (2), and femur, rib, and scapula (1 each). Patients' ages ranged from 5 to 33 years. The tumors measured from 2.0 to 6.5 cm in the greatest diameter (mean = 4.1 cm) and most patients presented with low-grade pain at the affected site. Imaging studies showed expansile lytic lesions with cortical thickening and a mild rim of sclerosis. Histologically all tumors were characterized by active production of bone with a fibrovascular stroma containing microtrabecular aggregates of bone matrix. The osteoblastic proliferation was atypical and showed enlarged cells with prominent nucleoli and abundant cytoplasm imparting them with a striking epithelioid appearance. Immunohistochemical studies showed variable results that caused difficulties for interpretation; 4 of 12 cases showed strong nuclear positivity for FOS, 2 of 12 cases showed strong diffuse nuclear positivity for FOSB; the remaining cases showed variable, sometimes overlapping patterns, considered to be indeterminate. Ki-67 proliferation marker showed low nuclear positivity (∼2%) in 10 cases and a slight increase (<10%) in two cases. Clinical follow-up was available in 14 patients; one patient experienced a recurrence at six months that was treated with additional curetting; the remainder of the patients were all alive and well without evidence of recurrence from 1 to 22 years (median follow up = 3 years). Epithelioid osteoblastoma is an unusual variant of osteoblastoma that has the potential for simulating a malignancy and does not appear to be associated with a more aggressive behavior.

It Takes a Village: Providing International Pediatric Pathology Services in a Resource-Limited Setting

OBJECTIVES: Partnerships between low- to middle-income countries (LMICs) and high-income countries (HICs) is one strategy to mitigate observed health disparities. Cambodia's Angkor Hospital for Children (AHC), an LMIC institution, faces shortages in health care resources, including pathology services. A partnership was created with Children's Wisconsin (CW), an HIC hospital, including provision of pathology services. We describe our established pathology workflow, examine cases seen in AHC patients, and evaluate the impact of CW's interpretations. METHODS: AHC provides clinical history and impression and ships samples to CW, which processes the samples, and pathologists provide interpretations, sending reports electronically to AHC. For analysis, final diagnoses were considered "concordant," "refined," or "discordant" based on agreement with the clinical impression. Cases were also classified as "did not change management" or "changed management" based on how CW interpretation affected clinical management. RESULTS: We included 347 specimens (177 malignant, 146 benign, 24 insufficient for diagnosis). Of these cases, 31% were discordant and 44% of cases with clinical follow-up had a change in management with CW interpretation. CONCLUSIONS: Inclusion of pathology services in LMIC-HIC partnerships is crucial for resolving health disparities between the institutions involved. The described partnership and established pathology workflow can be adapted to the needs and resources of many institutions.

A Summary of the Inaugural WHO Classification of Pediatric Tumors: Transitioning from the Optical into the Molecular Era.

Pediatric tumors are uncommon, yet are the leading cause of cancer-related death in childhood. Tumor types, molecular characteristics, and pathogenesis are unique, often originating from a single genetic driver event. The specific diagnostic challenges of childhood tumors led to the development of the first World Health Organization (WHO) Classification of Pediatric Tumors. The classification is rooted in a multilayered approach, incorporating morphology, IHC, and molecular characteristics. The volume is organized according to organ sites and provides a single, state-of-the-art compendium of pediatric tumor types. A special emphasis was placed on "blastomas," which variably recapitulate the morphologic maturation of organs from which they originate. SIGNIFICANCE: In this review, we briefly summarize the main features and updates of each chapter of the inaugural WHO Classification of Pediatric Tumors, including its rapid transition from a mostly microscopic into a molecularly driven classification systematically taking recent discoveries in pediatric tumor genomics into account.

CLU blocks HDACI-mediated killing of neuroblastoma.

Clusterin is a ubiquitously expressed glycoprotein with multiple binding partners including IL-6, Ku70, and Bax. Clusterin blocks apoptosis by binding to activated Bax and sequestering it in the cytoplasm, thereby preventing Bax from entering mitochondria, releasing cytochrome c, and triggering apoptosis. Because increased clusterin expression correlates with aggressive behavior in tumors, clusterin inhibition might be beneficial in cancer treatment. Our recent findings indicated that, in neuroblastoma cells, cytoplasmic Bax also binds to Ku70; when Ku70 is acetylated, Bax is released and can initiate cell death. Therefore, increasing Ku70 acetylation, such as by using histone deacetylase inhibitors, may be therapeutically useful in promoting cell death in neuroblastoma tumors. Since clusterin, Bax, and Ku70 form a complex, it seemed likely that clusterin would mediate its anti-apoptotic effects by inhibiting Ku70 acetylation and blocking Bax release. Our results, however, demonstrate that while clusterin level does indeed determine the sensitivity of neuroblastoma cells to histone deacetylase inhibitor-induced cell death, it does so without affecting histone deacetylase-inhibitor-induced Ku70 acetylation. Our results suggest that in neuroblastoma, clusterin exerts its anti-apoptotic effects downstream of Ku70 acetylation, likely by directly blocking Bax activation.

Endothelial microparticles induce inflammation in acute lung injury.

BACKGROUND: Previously, we have shown that endothelial microparticles (EMPs) injected into mice induce acute lung injury (ALI) [1]. In this study, we hypothesize that EMPs induce ALI by initiating cytokine release in the lung, leading to recruitment and activation of neutrophils. MATERIALS AND METHODS: C57BL/6J male mice (8-10 wk old) were intravenously injected with EMPs (200,000/mL), LPS (2 mg/kg), or both. Bronchoalveolar lavage (BAL) and serum levels of IL-1ß and TNF-α were analyzed by enzyme-linked immunoassay (ELISA). Morphometric analysis was performed on H and E stained lung sections. Myeloperoxidase (MPO) levels were determined via an enzymatic assay and immunofluorescence of stained sections. RESULTS: EMPs led to significantly increased pulmonary and systemic IL-1ß and TNF-α levels, which correlated with increased neutrophil recruitment to the lung. MPO levels in the lungs were increased significantly following injection of EMPs or LPS, compared to PBS. In mice treated with EMPs and LPS either simultaneously or successively, the cytokine and MPO levels were significantly increased over that of either treatment alone. CONCLUSION: EMPs contribute to lung injury through the initiation of a cytokine cascade that increases recruitment of neutrophils and subsequent release of MPO. Furthermore, treatment of mice with both EMPs and LPS induced greater lung injury than either treatment alone, suggesting that EMPs prime the lung for increased injury by other pathogens. Therapies aimed at reducing or blocking EMPs may be a useful strategy for attenuating lung injury.

Optical Metabolic Imaging of Mitochondrial Dysfunction on HADH Mutant Newborn Rat Hearts.

BACKGROUND: Mitochondrial [Formula: see text]-oxidation of fatty acids is the primary energy source for the heart and carried out by Hydroxy Acyl-CoA Dehydrogenase (HADH) encoded trifunctional protein. Mutations in the genes encoding mitochondrial proteins result in functionally defective protein complexes that contribute to energy deficiencies, excessive reactive oxygen species (ROS) production, and accumulation of damaged mitochondria. We hypothesize that a dramatic alternation in redox state and associated mitochondrial dysfunction is the underlying cause of Fatty Acid Oxidation (FAO) deficiency mutant, resulting in heart failure. Mitochondrial co-enzymes, NADH and FAD, are autofluorescent metabolic indices of cells when imaged, yield a quantitative assessment of the cells' redox status and, in turn, that of the tissue and organ. METHOD: We utilized an optical cryo-imager to quantitively evaluate the three-dimensional distribution of mitochondrial redox state in newborn rats' hearts and kidneys. Redox ratio (RR) assessment shows that mitochondrial dysfunction is extreme and could contribute to severe heart problems and eventual heart failure in the mutants. RESULTS: Three-dimensional redox ratio (NADH/FAD) rendering, and the volumetric mean value calculations confirmed significantly decreased cardiac RR in mutants by 31.90% and 12.32%, in renal mitochondrial RR compared to wild-type control. Further, histological assessment of newborn heart myocardial tissue indicated no significant difference in myocardial tissue architecture in both control and severe (HADHAe4-/-) conditions. CONCLUSION: These results demonstrate that optical imaging can accurately estimate the redox state changes in newborn rat organs. It is also apparent that the FAO mutant's heart tissue with a low redox ratio is probably more vulnerable to cumulative damages than kidneys and fails prematurely, contributing to sudden death.