Reticulin Fibers Research Articles

Molecular profile of inflammatory and megakaryocytic factors in pediatric myelodysplastic syndrome with acute myelofibrosis

Pediatric fibrotic myelodysplastic syndromes (ped-MDS-MF) and pediatric primary myelofibrosis (ped-PMF) are rare, and the molecular changes which mediate fibrosis have never been investigated. Histology and gene expression profile of 119 fibrosis/angiogenesis/inflammation/megakaryopoiesis-related factors in bone marrow biopsies were performed (two ped-MDS-MF and one ped-PMF). In one progressive ped-MDS, comparison of MF grade 0 (no myelofibrosis) and MF grade 2 (dense network of reticulin fibres) after 4 months showed that expression of fibrosis-related transcripts increased and dysplastic megakaryocytes formed a dense net of CD42b+ proplatelets. These changes were not observed in another ped-MDS-MF, whereas ped-PMF showed a similar proplatelet pattern. These findings indicate that fibrotic changes in ped-MDS may involve proplatelet-related and unrelated pathways.

Diagnosing pituitary adenoma in unstained sections based on multiphoton microscopy.

If we can find a new method that can achieve rapid diagnosis of adenoma during operation, it will help surgeon shorten the operation time and enhance the treatment efficacy. This study discusses the feasibility of multiphoton microscopy (MPM) in diagnosing pituitary adenoma. MPM, based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) is performed for the diagnosis of pituitary adenoma in unstained sections. Our results show that MPM can reveal the variation of reticulin fiber by SHG signals of collagen, combined with the measurement of area of acinus, thickness of collagen fiber and collagen percentage. MPM can further reflect the change of meshwork in normal pituitary and hyperplasia quantitatively. And the characteristics of typical growth patterns of pituitary adenoma are demonstrated by the overlay of SHG and TPEF images. What's more, we can identify the boundary of normal pituitary, hyperplasia and adenoma from MPM images. And the experiment also results verify the feasibility of this method in frozen sections. These results indicated that MPM can make a diagnosis of pituitary adenoma by the morphological changes without routine pathological processing including hematoxylin-eosin (H&E) staining and other special staining. Therefore, this technique is expected to help diagnosis of pituitary adenoma during operation.

Clinicopathological and genetic association between epithelioid glioblastoma and pleomorphic xanthoastrocytoma.

Epithelioid glioblastoma (eGBM) is a rare variant of GBM which was adopted in the 2016 WHO classification. eGBM and pleomorphic xanthoastrocytoma (PXA) sometimes show overlapping features histologically and genetically, such as epithelioid pattern and a highly frequent V600E mutation in the gene for vRAF murine sarcoma viral oncogene homolog B1 (BRAF), respectively. Accurate diagnosis of these rare tumors is challenging according to the new criteria in the revised 2016 WHO classification. It is an urgent task to elucidate the biological properties of the tumors and to select appropriate treatment. Twenty consecutive cases diagnosed as PXA or eGBM histologically were investigated. Twelve of the 20 cases were PXAs and eight were eGBMs. Morphologically, mitotic activity, necrosis and degenerative changes such as intracellular lipid accumulation, eosinophilic granular bodies and reticulin fiber deposits were scored. Immunohistochemical and molecular biological assessment for isocitrate dehydrogenases 1 and 2 (IDH1/2), α-thalassemia/mental-retardation-syndrome-X-linked gene (ATRX), p53, BRAF, telomere reverse transcriptase promoter (TERT-p), H3F3A, and integrase interactor 1 (INI1) were performed. eGBM tended to lack the degenerative changes characteristic for PXA. Of the 20 cases tested, Sanger technique showed no mutation in IDH1/2. BRAF mutation at T1799 > A (V600E) was detected in 4/12 (33.3%) PXA and 4/8 (50.0%) eGBM, while TERT-p mutation was detected at C228 > T in 2/12 (16.7%) PXA and at C250 > T in 1/8 (12.5%) eGBM. Retained nuclear ATRX was observed in 12/12 (100%) PXA and 6/7 (85.7%) eGBM while p53 mutation was observed in 2/10 (20%) PXA and 7/7 (100%) eGBM. All tumors retained INI1 expression in their nuclei. None of the tumors harbored H3F3A mutation. One PXA without BRAF mutation acquired TERT-p mutation at recurrence and one eGBM harbored both BRAF and TERT-p mutation. Molecular biological similarity between eGBM and PXA was suggested in our series, while degenerative changes reflected the features of PXA. It was speculated that the common genetic alterations for development and progression of eGBM and PXA might include BRAF and TERT-p mutations.

Histologic Analysis of Retrieved Synthetic Ligaments Implanted in Dogs for Treatment of Cranial Cruciate Ligament Disease

Objective: To histologically analyze retrieved synthetic liagments implanted in canine stifles for the treatment of cranial cruciate ligament disease.Animals: 6 client-owned dogsProcedures: Synthetic ligaments (SL) were retrieved from 6 dogs. Five had experienced postoperative complications which necessitated their removal and 1 dog died of unrelated causes. The formalin fixed SLs were stained with hematoxylin and eosin, Masson’s trichrome, Alcian blue, Vimentin and Reticulin stains using standard histologic staining protocols and examined histologically via normal light microscopy. The histologic evaluation involved both a qualitative description and semiquantitative assessment of each dog’s cellular response to the implanted SL. Additionally, a semiquantitative scoring system was used for describing the distribution and amount of fibroblasts around and within the central (inner 1/2) and peripheral (outer 1/2) zones and individual core fibers of the synthetic ligaments.Results: Sheath and core segments had amounts of cellular infiltration which ranged from minimal to moderate which consisted primarily of fibroblasts with rare multinucleate giant cells present and no evidence of lymphoid or inflammatory cellular infiltrates. Peripheral zone fibroblast ingrowth ranged from minimal to moderate and infiltration consistently decreased into the central (inner ½) zones. There was a minimal amount of fibroblast infiltration and encircling of individual core fibers. Infiltrating fibroblasts deposited collagen matrix and mild to moderate amounts of reticulin fibers within the hypercellular regions of the sheath with lesser amounts in the core segments.Conclusions and Clinical Relevance: The structure and composition of this synthetic ligament supported variable amounts of fibroblast ingrowth and activity while inducing a minimal amount of inflammatory cell infiltration.

Abstract 37: An unusual case of myelofibrosis with a JAK2 H538QK539L mutation associated with nephrotic syndrome

Abstract Introduction: Activating Janus kinase 2 (JAK2) mutations have been described in myeloproliferative neoplasms (MPNs) since 2005. Since its initial discovery, the JAK2 V617F mutation has been described in more than 95% of patients with polycythemia vera (PV) and in 50-60% of patients with essential thrombocythemia (ET) and primary myelofibrosis (PMF). Subsequent efforts were made to identify molecular mutations in MPN cases lacking the V617F mutation and further mutations in the exon 12 domain of the JAK2 were identified in PV patients. However, there have been only a few studies evaluating the presence of these JAK2 exon 12 mutations in PMF patients. Case Report: A 60-year-old Malay gentleman with no known prior medical history of note presented at our Emergency Department with a 1-week history of bipedal edema and exertional dyspnea. Physical examination revealed bibasal coarse crepitations with moderate hepatosplenomegaly. Laboratory investigations revealed normochromic, normocytic anemia, thrombocytopenia, hypoalbuminemia, and elevated creatinine levels. A spot urine sample showed a protein to creatinine ratio of 93 mg/mmol with an estimated total urinary protein (TUP) of 0.8 g/day. Further workup of his renal impairment, which included an autoimmune screen, hepatitis, and humman immunodeficiency tests, were all unremarkable. A myeloma screen revealed elevated immunoglobulin G levels of 29.18 g/L but with no monoclonal bands detected. Transthoracic echocardiography showed mild pulmonary hypertension with a pulmonary artery systolic pressure (PASP) of 45 mmHg, but the ejection fraction was normal at 65%. He was also noted incidentally to have a prolonged prothrombin time (PT), activated partial thromboplastic time (APTT), and thrombin clotting time. Fibrinogen levels were normal and a lupus anticoagulant was not detected. Bone marrow aspiration and biopsy results were consistent with myelofibrosis and diffuse coarse reticulin fibers of grade 4 were reported. Quantitative BCR-ABL messenger ribonucleic acid (mRNA), JAK2 V617F, and calreticulin (CALR) mutations were negative. However, a JAK2 H538QK539L (mutation leading to a substitution of glutamine for histidine at position 538 and leucine for lysine at position 539) in exon 12 was detected. Incidentally, iron stores were absent on the bone marrow aspirate sample. Ultrasound (US) and computed tomography (CT) scans showed the presence of hepatosplenomegaly with portal hypertension with no evidence of any venous thrombosis. A nonobstructive left renal calculi was seen but no other renal abnormality was detected. He was started on low-salt diet, fluid restriction, diuretic, and iron supplements. Within 1 month, his hemoglobin increased from 7.7g/dL to 14 g/dL with a rise in hematocrit to 52.1%. His iron supplements were stopped and he required 3 sessions of venesection in total to control his hematocrit. Subsequently, he was commenced on hydroxyurea for cytoreduction. His spleen reduced in size and his proteinuria normalized after 10 months. However, he developed worsening anemia and hydroxyurea had to be stopped. On follow-up, his hemoglobin increased to 12 g/dL with a baseline platelet count of > 100 X 109/L. Throughout this period, his bipedal edema remained chronic but he was not consistent with his renal follow-ups. Within 12 months, his proteinuria started increasing and is now within the nephrotic range. Discussion: We describe here a patient who was diagnosed with a JAK2 V617F negative PMF. Subsequent analysis revealed that he was harboring a JAK2 exon12 mutation instead. This was associated with a deranged coagulation profile and proteinuria which responded to hydroxyurea. This patient was never diagnosed with PV previously and thus did not meet the criteria for post-PV myelofibrosis. Also, we believe that this is the first case of a JAK2 exon12 mutation occurring in a myelofibrotic patient. Given the recent description of MPN-related glomerulopathy and the response of this patient to hydroxyurea, we believe further investigations into the associations of triple-negative (JAK2 V617F, myeloproliferative leukemia virus oncogene (MPL) and CALR negative) PMF with JAK2 exon12 mutations and the associated organ involvements may increase our knowledge of the pathogenesis of this rare condition. Citation Format: Moon Ley Tung, Hersharan Kaur Sran. An unusual case of myelofibrosis with a JAK2 H538QK539L mutation associated with nephrotic syndrome [abstract]. In: Proceedings of the Second AACR Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; May 6-9, 2017; Boston, MA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(24_Suppl):Abstract nr 37.

Histomorphometric approach to differentiate skin lesions of tuberculoid leprosy from sarcoidosis.

More than 200 000 new cases of leprosy are detected worldwide annually. Physicians commonly have difficulty in differentiating tuberculoid form of leprosy (TL) from sarcoidosis' cutaneous manifestation. Skin biopsies of 33 patients with TL and 24 with sarcoidosis were reviewed on hematoxylin and eosin- and Gomori-stained sections, in order to find reliable criteria for distinguishing one disease from another. Nine of the 24 features analyzed presented significant predictive value for diagnosis (P < .05). Predominance of tuberculoid granulomas in adnexal and neural distribution, and granulomas replacing the nerves localized within sweat gland glomeruli were predictive to TL diagnosis. For sarcoidosis, dermal fibrosis, back-to-back distribution of the granulomas, presence of atypical giant cells and plasma cells, greater number of conventional giant cells, and spared nerves beside the granuloma were predictive criteria. The median surface density of reticulin fibers was significantly higher in sarcoidosis (3.44) than in TL (2.99). Nonetheless, using logistic regression, this variable did not discriminate between the diseases (P = .096). Isolated histological features are not fully predictive to differentiate the 2 diseases. However, those with statistical value can assist this distinction in diagnostic practice. Although the results of the analysis of the reticulin fibers density did not tell apart TL from sarcoidosis, they corroborate the idea of fiber fragmentation within tuberculoid leprosy granulomas, reiterating the importance of morphometry in the histological examination.

Khat it out! A Nodular Regenerative Hyperplasia Case

Nodular regenerative hyperplasia (NRH), is a rare liver disease marked by diffuse transformation of normal hepatic parenchyma into small, regenerative nodules with little to no fibrosis, which can lead to portal hypertension. Incidence varies and is associated with chronic or recurrent infection, exposure to drugs or toxins, hypercoagulability, immunologic disorders or genetic disorders. The use of khat has never been reported as a potential cause of NRH, but it is a known cause of acute hepatitis and cirrhosis. We report a case of a young women who developed NRH in the setting of prior khat use. A 31 year old woman from Yemen presented with worsening abdominal pain and jaundice over several months. She denied alcohol use, but reported a remote history of khat use 7 years ago. On initial evaluation, her vitals were normal and physical exam was significant for scleral icterus, abdominal ascites, and palpable hepatosplenomegaly. Laboratory testing revealed severe pancytopenia and liver tests significant for ALP/ALT/AST of 214/112/116, respectively. Coagulation studies were normal. MRI of the abdomen showed patent portal veins, portal hypertension with marked splenomegaly, and extensive periesophageal, perisplenic, perigastric and abdominal varices. A comprehensive infectious, autoimmune and anticoagulation workup was done and unremarkable. On upper endoscopy, small varices were found in the distal esophagus without stigmata of bleeding, as well as moderate portal hypertensive gastropathy (PHG) in the gastric fundus and body. A liver biopsy revealed regenerative hepatocyte plate architecture and patchy sinusoidal dilatation, consistent with nodular regenerative hyperplasia (Image 2). She was treated with carvedilol for anemia secondary to PHG. NRH is a diagnosis of exclusion with liver biopsy being the gold standard for diagnosis. Clinical evidence of portal hypertension without evidence of cirrhosis is key when including NRH in the differential diagnosis. Khat use has been reported to cause acute liver injury and when severe, may cause fibrosis and cirrhosis. Upon literature review, khat has not been shown to be associated with NRH. Thorough history taking and exclusion of more common causes of liver disease i.e. infectious hepatitis and alcoholic or non-alcoholic fatty liver disease, are crucial prior to considering NRH.Figure: MRI Abdomen showing hepatosplenomegaly and nodular shrunken liver with hepatic fibrosis and portal venous distension.Figure: Small (< 5 mm) varices (arrows) noted in the lower third of the esophagus on upper endoscopy.Figure: Liver biopsy showing reduced reticulin fibers and expanded hepatocyte cell plates in an area of regeneration (reticulin stain).

Extramedullary haematopoiesis presenting with cardiac tamponade in a patient with polycythaemia vera

A 71-year-old man with a history of polycythaemia vera, diagnosed 4 years ago, presented to the emergency room with shortness of breath. A bedside echocardiogram revealed a large pericardial effusion...

Primary conjunctival myxoma: case series and review of the literature.

Myxomas are benign soft tissue tumours resembling primitive mesenchyme. They rarely involve ocular structures, and have been recognized in the conjunctiva, eyelids, cornea, and orbit. The aim of this study was to investigate the clinicopathological features of seven patients with primary conjunctival myxoma seen at Dr Luis Sánchez Bulnes Hospital, an ophthalmological referral centre in Mexico City. We reviewed the clinical, histochemical and immunohistochemical studies of patients with documented myxoma of the conjunctiva diagnosed in our hospital. Seven conjunctival myxomas were retrieved from 5923 conjunctival biopsies (0.1%). The mean age of patients was 40 years, with a range of 27-51 years. Females were more frequently affected, and none of our patients had systemic disease. The left eye was involved in five cases, and most of the lesions were located in the bulbar conjunctiva. Histopathological examination revealed a benign tumour composed of spindle-shaped and stellate-shaped cells immersed within an abundant mucinous matrix with sparse vessels and reticulin fibres. Immunohistochemistry demonstrated positivity for vimentin and negativity for smooth muscle actin, SOX10 and GLUT1 in myxoma cells of all cases. S100 was found to be positive in four cases, and muscle-specific-actin in three cases. Conjunctival myxomas are uncommon tumours. For accurate diagnosis, histopathological examination is mandatory. The treatment of choice is surgical removal, and the prognosis is excellent.

Bone marrow fibrosis at diagnosis predicts survival for primary acute myeloid leukemia.

As a desmoplastic reaction, tissue fibrosis played crucial roles in solid tumor progression, chemo-resistance, and consequently heralded poor clinical outcome. Previous studies implied the effects of marrow fibrosis on prognosis for acute lymphoblastic leukemia were disputable. In this study, we aimed to investigate the potential role of bone marrow fibrosis on clinical survival in acute myeloid leukemia (AML) patients. Bone marrow fibrosis (evaluated as reticulin fiber density, RFD) in bone marrow sections was evaluated at diagnosis via computer technology. Receiver operating characteristic curve (ROC) was used to analyze the predictive value of RFD for relapse and survival status. Kaplan-Meier method was used to estimate survival rates per subgroup between patients with different RFD. Cox proportional hazard regression was used to model the overall survival. High RFD at diagnosis in bone marrow sections from primary AML might predict early relapse and shorter survival (P=0.003 and 0.001, respectively). The optimal cutoff value of RFD at diagnosis was determined to be 7.2%. Furthermore, the Kaplan-Meier analysis indicated that patients with high marrow RFD had shorter relapse-free survival (RFS) and overall survival (OS) than patients with low RFD (P=0.007 and 0.000, respectively). Multivariate analysis suggested that similar with cytogenetics, marrow RFD at diagnosis was an independent prognostic factor for RFS [HR 0.564, 95% confidence interval (CI) 0.338-0.940, P=0.028] and OS (HR 0.457, 95% CI 0.225-0.929, P=0.031) in primary AML patients. Our data suggest that marrow RFD before treatment should be seemed as prognostic factor in primary AML, it may provide valuable clues for developing new targeted therapy.

Correlation between Bone Marrow Fibrous Proliferation and Prognosis of Acute Myeloid Leukemia

To investigate the correlation between the bone marrow fibrous proliferation and the prognosis of acute myeloid leukemia(AML). The quantitative method was used to analyze the reticulin fiber density (RFD) of AML patients. the bone marrow sections from 39 primary AML patients and 35 normal controls were collected to compare the RFD between these 2 groups. The prognosis value of RFD for AML were estimated by using appropriate statistical analysis. RFD in primary AML was significantly higher than that in normal controls(2.41%±0.23% vs 1.14%±0.06%)(P<0.05). Relapse-free survival(RFS) analysis showed that the patients with RFD more than 1.68% indicated poor RFS, and the overall survival(OS) analysis showed that patients with RFD more than 2.66% indicated poor overall survival (P<0.05). Besides, there were no relationship between RFD and the BM blast count (r=0.01) and WBC counts (r=0.04) at diagnosis(P>0.05). The RFD in bone marrow is a high risk factor in poor prognosis of AML patients.

Incidence of Myelofibrosis in Chronic Myeloid Leukemia, Multiple Myeloma, and Chronic Lymphoid Leukemia during Various Phases of Diseases.

Pathomorphological study of trephinobiopsy specimens from 129 patients with lymphoproliferative and myeloproliferative diseases was carried out over the course of chemotherapy. Combinations of initial and manifest myelofibrosis (loose network of reticulin fibers and extensive network of reticulin and collagen fibers, respectively) predominated at the debut of chronic myeloid leukemia, chronic lymphoid leukemia, and multiple myeloma. Manifest myelofibrosis was detected in patients with chronic myeloid leukemia without hematological response (failure of normalization of hematological values) and in patients with progressing and relapsing multiple myeloma. Combinations of foci of initial and manifest myelofibrosis were most incident in patients with progressing and relapsing chronic lymphoid leukemia. The incidence of myelofibrosis was higher in patients with multiple myeloma and chronic lymphoid leukemia progression and relapses and in patients with chronic myeloid leukemia without hematological response than at the disease debut and in case of response to chemotherapy. The response to chemotherapy in patients with chronic myeloid leukemia and chronic lymphoid leukemia was associated with a decrease in the incidence of myelofibrosis. In patients with multiple myeloma responding to chemotherapy, the incidence of myelofibrosis did not change in comparison with the disease debut.

A stiff extracellular matrix is associated with malignancy in peripheral neuroblastic tumors.

Improved prognosis for patients with peripheral neuroblastic tumors (PNB) depends on enhanced pretreatment risk stratification combined with research into new therapeutic targets. This study investigated the potential contribution of extracellular matrix (ECM) elements toward this endeavor. We characterized certain elements such as reticulin fibers, collagen type I fibers, and elastic fibers by digital pathology in almost 400 untreated PNB. A reticular and poorly porous ECM was identified in neuroblastomas (NBs) from patients with clinical and biological features associated with poor prognosis compared with a loose and permeable matrix found in NBs of the favorable cohort. Aggressiveness patterns of ECM can be accurately determined by morphometric tools and could become candidate elements for novel therapies.

Diagnosis of adrenocortical tumors by reticulin algorithm

Aims:To apply reticulin algorithm (RA) to the diagnosis of adrenocortical tumors on adrenalectomy specimens and compare its efficacy to the modified Weiss criteria or Lin–Weiss–Bisceglia (LWB) criteria for oncocytic variant.Materials and Methods:Adrenocortical tumors (ACTs) diagnosed on resected specimens including the variants during January 2010–June 2016 were retrieved from the pathology records. The demographic and clinical data were obtained from medical records. The functional status of the tumor was noted based on clinical and biochemical evaluation. The location, size, and gross appearance of the tumor were noted. The corresponding hematoxylin and eosin-stained slides were independently assessed by two pathologists applying modified Weiss criteria and LWB criteria for the oncocytic variant as applicable. Reticulin stain was performed on representative sections in all cases. All the tumors were classified according to RA, and the diagnoses made by each system were correlated.Results:There were 15 ACTs in the study period. There were two adenomas including one oncocytoma which showed Weiss score (WS) of 2 and intact reticulin framework. There were 13 adrenal cortical carcinomas including two oncocytic variants with WS ranging from 4 to 7. There was disruption of reticulin and thick, irregular reticulin fibers in all tumors, irrespective of the histology. It correlated with modified Weiss and LWB criteria.Conclusions:The RA was simple, easy to apply, and correlated well with modified Weiss criteria in the diagnosis of ACTs including the oncocytic variant.

To study the length, thickness, density and staining intensity of reticulin fibers in various grades of oral squamous cell carcinoma

To study the length, thickness, density and staining intensity of reticulin fibers in various grades of oral squamous cell carcinoma

Bone Marrow-Specific Loss of ABI1 Induces Myelofibrosis through a Mechanism Involving Activation of NFκB

Primary myelofibrosis (PMF) is an age-related myeloproliferative neoplasm (MPN) characterized by progressive bone marrow fibrosis, increasingly ineffective hematopoiesis, vascular and inflammatory complications, and progression to acute myeloid leukemia (AML) in 20% of cases. PMF is the rarest and the most severe of MPNs, with unfavorable prognosis and challenging treatment. Constitutive activation of the JAK-STAT pathway is an essential contributor to the pathogenesis of PMF. Nonetheless, clinically available JAK inhibitors do not show consistent disease-modifying effects at the molecular and malignant stem cell levels, underscoring the need to identify other targetable pathogenic mechanisms in PMF and related MPNs.We recently described a new signaling cascade involved in the maintenance of the malignant phenotype of stem cells in chronic myeloid leukemia that affects their adhesiveness, interaction with the microenvironment and resistance to imatinib (Chorzalska et al., Leukemia 2014). These phenotypic changes were caused by loss of Abelson interactor-1 (Abi-1) which regulates integrin α4 and the Src family kinases (SFKs) signaling pathways. To further delineate how organ-specific absence of Abi-1 affects hematopoiesis and hematopoietic stem cells, we generated a conditional, inducible bone marrow-specific Abi-1 transgenic mouse knockout model. For this purpose, we crossed conditional Abi-1(fl/fl) knockout mice with transgenic Tg(Mx1-cre+/-) mice (B6.Cg-Tg(Mx1-cre+ 1Cgn/J) that express Cre recombinase under the control of the polyinosinic:polycytidylic acid (poly(I:C)) or interferon-inducible Mx1 promoter. Obtained Abi-1(fl/fl);Tg(Mx1- cre(+)) animals were subjected to bone marrow-specific Abi-1 deletion induced by intraperitoneal administration of poly(I:C), resulting in organ-specific Abi-1 knockout (Abi-1 KO). Abi-1(fl/fl);Tg(Mx1- cre(-)) animals subjected to the same poly(I:C) treatment (Abi-1 WT) were used as controls in all experiments (Figure 1A). We confirmed the absence of Abi-1 protein in the Abi-1 KO bone marrow by immunoblotting (Figure 1B). Abi-1 KO mice developed deranged hematopoiesis with progressive anemia, thrombocythemia, megakaryocytosis, and myeloid hyperplasia (Figure 1C). They also developed progressive splenomegaly with 1.4x, 2.4x, and 4.8x enlargement of the spleen at 4, 28, and 50 weeks after recombination, respectively, and progressive femur pallor (Figure 1D) with bone marrow fibrosis confirmed by trichrome and silver staining (Figure 1D). Using fluorescence-activated cell sorting, we determined that Abi-1 KO resulted in more than two-fold expansion of the most primitive long-term hematopoietic stem cells (Lin-CD34-Sca-1+c-Kit+ CD135-) in the bone marrow and 3.75-fold increase of LSK cells (Lin- Sca-1+c-Kit+) in the peripheral blood compared with controls (Figure 1E). Increased activities of the SFKs and NFκB were observed in Abi-1 KO bone marrow, and confirmed in human CD34+ cells isolated from the marrow of patients with PMF or AML (Figure 1F,G). Furthermore, CD34+ hematopoietic progenitors and granulocytes from PMF patients, as well as CD34+ hematopoietic progenitors from AML patients, showed decreased levels of ABI1 transcript (Figure 1H).Taken together, our results indicate that a targeted deactivation of Abi-1 in the bone marrow causes expansion of hematopoietic stem cells, myeloid hyperplasia with thrombocytosis and overproduction of collagen and reticulin fibers. The Abi-1 KO murine phenotype meets the Mouse Models of Human Cancers Consortium criteria for a myeloproliferative neoplasm with features resembling human PMF (Kogan et al., Blood 2002). These data indicate that loss of Abi-1 is sufficient for initiation of bone marrow fibrosis, and that Abi-1-SFKs-NFκB cross-talk may represent a new molecular target for the treatment of PMF.Bone marrow-specific, conditional Abi-1 KO animals represent a new model of PMF offering a unique opportunity to interrogate the molecular details of the Abi-1-driven mechanism that leads to the development of stem cell-derived MPNs, and to elucidate potential novel therapeutic approaches that directly address their pathogenesis. [Display omitted] DisclosuresOlszewski:Bristol-Myers Squibb: Consultancy; Genentech: Research Funding; TG Therapeutics: Research Funding. Reagan:Alexion: Honoraria; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees.

Determining the Signal Source in Magnetic Resonance Imaging of Myelofibrotic Bone Marrow

Magnetic resonance imaging (MRI) is a promising diagnostic method for evaluation of bone marrow myelofibrosis for offering non-invasive, wider-area coverage over conventional histology. Although the most striking feature in histology of myelofibrotic bone marrow is the proliferation of reticulin fibers, the spectrum of findings involves abnormalities in cell number and composition, vessel proliferation, as well as possible pre-fibrotic abnormalities in matrix such as inflammation/edema. Correlation of MRI observations with such histological findings to accurately define the pathogenic phases of myelofibrosis has been challenging. Here, we present the first MRI analysis of myelofibrosis in a mouse model (Gata-1low mice) in an attempt to correlate MRI signal observations with histological findings. T2-weighted MRI images of femur bone marrow of Gata-1low animals at different ages (12 to 46 weeks) showed high MR signal intensity, absent in age-matched wild-type controls, that is detected as early as 12 weeks of age, before onset of histologically-defined fibrosis in this mouse model. MRI acquisitions employing fat suppression, a technique that suppresses signals from lipids, together with the absence of chemical shift artifacts in the images, excluded the possibility of lipids as the source of the prominent MR signal. To determine the source of this prominent non-lipid signal in Gata-1low bone marrow, cellular composition, vascularization and vascular permeability were tested. Our findings demonstrate a multi-source nature of MRI signals in bone marrow, which evolves from young (12 weeks) to old (40 weeks) Gata-1low bone marrow consistent with the pathologic progression of myelofibrosis. Data support the importance of an integrative approach to further the development of this non-invasive modality for following the dynamics and progression of this multifactorial pathology in humans. DisclosuresNo relevant conflicts of interest to declare.

Quantitative histological image analyses of reticulin fibers in a myelofibrotic mouse.

Bone marrow (BM) reticulin fibrosis (RF), revealed by silver staining of tissue sections, is associated with myeloproliferative neoplasms, while tools for quantitative assessment of reticulin deposition throughout a femur BM are still in need. Here, we present such a method, allowing via analysis of hundreds of composite images to identify a patchy nature of RF throughout the BM during disease progression in a mouse model of myelofibrosis. To this end, initial conversion of silver stained BM color images into binary images identified two limitations: variable color, owing to polychromatic staining of reticulin fibers, and variable background in different sections of the same batch, limiting application of the color deconvolution method, and use of constant threshold, respectively. By blind coding image identities, to allow for threshold input (still within a narrow range), and using shape filtering to further eliminate background we were able to quantitate RF in myelofibrotic Gata-1low (experimental) and wild type (control) mice as a function of animal age. Color images spanning the whole femur BM were batch-analyzed using ImageJ software, aided by our two newly added macros. The results show heterogeneous RF density in different areas of the marrow of Gata-1low mice, with degrees of heterogeneity reduced upon aging. This method can be applied uniformly across laboratories in studies assessing RF remodeling induced by aging or other conditions in animal models.

Role of non-mulberry silk fibroin in deposition and regulation of extracellular matrix towards accelerated wound healing

A facile fabrication of a ready-to-use bioactive wound dressing capable of concomitantly accelerating the healing process as well as deposition of the extracellular matrix (ECM) to circumvent further scarring complicacies has become a focal point of research. In this backdrop, our present work is based on non-mulberry silk fibroin (NMSF) electrospun antibiotic loaded semi-occlusive mats, mimicking the ECM of skin in terms of morphology, topology, microporous structure and mechanical stiffness. Regulation of ECM deposition and isotropic orientation evinced the potential of the mat as an instructive platform for skin regeneration. The unique peptide motifs of NMSF assisted the augmented recruitment of fibroblast, keratinocytes and endothelial cells leading to accelerated wound healing. Early progression of mature granulation, faster re-epithelialization and angiogenesis in the wounds in in vivo rabbit model forwarded the blended nanofibrous mats of NMSF and PVA ferrying EGF, apt for scarless healing.

Pleomorphic xanthoastrocytoma arising from the suprasellar region: A report of two cases

Pleomorphic xanthoastrocytoma (PXA) is a rare astrocytic neoplasm that usually arises in children and young adults. Typically, lesions of PXA are superficially located in the cerebral hemispheres. Herein, we report two extremely rare patients with PXA arising from suprasellar regions. One of the patients is a 29-year-old man admitted to our hospital with a history of progressive headache for 1month. The patient’s brain MRI revealed a large tumor arising from the suprasellar cistern of the third ventricle. The second patient, a 52-year-old woman, presented with progressive dizziness and visual disturbance that had developed over the course of 1year. The MRI revealed a well-enhanced suprasellar solid mass measuring 1.4×1.2×1.4cm. Both patients underwent surgical removal of their tumors, and both patients showed similar microscopic structures and immunohistochemical phenotypes: the tumor cells were pleomorphic with mixtures of spindle-shaped, and multinuclear giant cells. In addition, eosinophilic granular bodies and xanthomatous cells were seen on section. Immunohistochemistry was positive for GFAP, S-100, and CD34, and was negative for IDH 1, CK, and Syn. The Ki-67 proliferation index was less than 1%. Silver impregnation revealed reticulin fibers surrounding the individual tumor cells, and small cell groups. Based on these findings, the two patients were diagnosed with PXA in the suprasellar region. To date, only five such patients have been reported in the literature. PXA should be included in the differential diagnosis for tumors arising in the sellar region.