Continuous Indexing of Fibrosis (CIF): improving the assessment and classification of MPN patients.

The grading of fibrosis in myeloproliferative neoplasms (MPN) is an important component of disease classification, prognostication and monitoring. However, current fibrosis grading systems are only semi-quantitative and fail to fully capture sample heterogeneity. To improve the quantitation of reticulin fibrosis, we developed a machine learning approach using bone marrow trephine (BMT) samples (n = 107) from patients diagnosed with MPN or a reactive marrow. The resulting Continuous Indexing of Fibrosis (CIF) enhances the detection and monitoring of fibrosis within BMTs, and aids MPN subtyping. When combined with megakaryocyte feature analysis, CIF discriminates between the frequently challenging differential diagnosis of essential thrombocythemia (ET) and pre-fibrotic myelofibrosis with high predictive accuracy [area under the curve = 0.94]. CIF also shows promise in the identification of MPN patients at risk of disease progression; analysis of samples from 35 patients diagnosed with ET and enrolled in the Primary Thrombocythemia-1 trial identified features predictive of post-ET myelofibrosis (area under the curve = 0.77). In addition to these clinical applications, automated analysis of fibrosis has clear potential to further refine disease classification boundaries and inform future studies of the micro-environmental factors driving disease initiation and progression in MPN and other stem cell disorders.

Pruritic rash following haploidentical stem cell transplantation.

A woman who had undergone haematopoietic stem cell transplantation presented with cutaneous features suggestive of graft-versus-host disease. Histopathological examination revealed a diffuse dermal infiltration of atypical monomorphic cells with a high proliferative index. Immunohistochemistry revealed positivity for monocytic markers, but negativity for T-cell markers.

Artificial intelligence-based morphological fingerprinting of megakaryocytes: a new tool for assessing disease in MPN patients.

Accurate diagnosis and classification of myeloproliferative neoplasms (MPNs) requires integration of clinical, morphological, and genetic findings. Despite major advances in our understanding of the molecular and genetic basis of MPNs, the morphological assessment of bone marrow trephines (BMT) is critical in differentiating MPN subtypes and their reactive mimics. However, morphological assessment is heavily constrained by a reliance on subjective, qualitative, and poorly reproducible criteria. To improve the morphological assessment of MPNs, we have developed a machine learning approach for the automated identification, quantitative analysis, and abstract representation of megakaryocyte features using reactive/nonneoplastic BMT samples (n = 43) and those from patients with established diagnoses of essential thrombocythemia (n = 45), polycythemia vera (n = 18), or myelofibrosis (n = 25). We describe the application of an automated workflow for the identification and delineation of relevant histological features from routinely prepared BMTs. Subsequent analysis enabled the tissue diagnosis of MPN with a high predictive accuracy (area under the curve = 0.95) and revealed clear evidence of the potential to discriminate between important MPN subtypes. Our method of visually representing abstracted megakaryocyte features in the context of analyzed patient cohorts facilitates the interpretation and monitoring of samples in a manner that is beyond conventional approaches. The automated BMT phenotyping approach described here has significant potential as an adjunct to standard genetic and molecular testing in established or suspected MPN patients, either as part of the routine diagnostic pathway or in the assessment of disease progression/response to treatment.

Value of Supraregional Multidisciplinary Review for the Contemporary Management of Testicular Tumors.

PURPOSE: Testicular cancers are an uncommon and highly curable group of tumors that are typically managed by specialist multidisciplinary teams (MDTs). Although recent guidelines have emphasized the importance of tumor prognostic factors in predicting recurrence and personalizing therapy in early-stage disease, the role of central pathology review in determining these factors is unclear. PATIENTS AND METHODS: We compared the referral histopathology reports with those obtained after expert central review for all cases reviewed by the UK Thames Valley Cancer Network testicular tumor MDT from August 2004 to September 2012. For cases in which the findings differed, we recorded the effect of the alteration on the estimates of patient prognosis and predicted clinical management using international (European Society of Medical Oncology [ESMO]) and local guidelines. RESULTS: The histopathology reports were altered after central review in 129 of 465 cases (27.7%) referred to the testicular tumor MDT during the study period. These resulted in changes in the estimation of prognosis for 42 patients (9.0% total), with a predicted affect on management according to the ESMO guidelines in 30 cases (6.5%). These proportions were broadly similar for both seminoma and nonseminoma, although the reasons for the discrepancies differed between the 2 (principally errors in categorization of rete testis invasion in seminoma and of lymphovascular invasion in nonseminoma). Changes to the tumor type were uncommon (2 cases). CONCLUSION: Central MDT review results in frequent, clinically relevant alterations to testicular tumor histopathology reports for testicular tumors. The results of our study demonstrate the importance of specialist MDTs to inform patient-centered care and ensure best practice in the management of these uncommon cancers.

Neorickettsia sennetsu as a Neglected Cause of Fever in South-East Asia.

Neorickettsia sennetsu infection is rarely recognized, with less than 100 globally reported patients over the last 50 years. The disease is thought to be contracted by eating raw fish, a staple of many South-East Asian cuisines. In 2009, the first patient with sennetsu was identified in the Lao PDR (Laos), raising the question as to how common this organism and related species are in patients presenting with fever. We investigated the frequency of N. sennetsu infection at hospitals in diverse areas of Laos. Consenting febrile hospital inpatients from central (Vientiane: n = 1,013), northern (Luang Namtha: n = 453) and southern (Salavan: n = 171) Laos were screened by PCR for N. sennetsu, if no previous positive direct diagnostic test was available. A PCR-restriction fragment length polymorphism assay was developed to differentiate between N. sennetsu, Ehrlichia chaffeensis and Anaplasma phagocytophilum. To allow more detailed studies of N. sennetsu, culture was successfully established using a reference strain (ATCC VR-367), identifying a canine-macrophage cell line (DH82) to be most suitable to visually identify infection. After screening, N. sennetsu was identified and sequence confirmed in four (4/1,637; 0.2%) Lao patients. Despite the previously identified high seroprevalence of N. sennetsu antibodies in the Lao population (~17%), acute N. sennetsu infection with sufficient clinical signs to prompt hospitalization appears to be rare. The reservoir, zoonotic cycle and pathogenicity of N. sennetsu remain unclear and require further investigations.

Severe falciparum malaria treated with artesunate complicated by delayed onset haemolysis and acute kidney injury.

BACKGROUND: Severe falciparum malaria may be complicated by haemolysis after parasite clearance, however the mechanisms remain unclear. Recent reports describe a pattern of delayed onset haemolysis among non-immune travellers with hyperparasitaemia treated with intravenous artesunate, termed post-artesunate delayed haemolysis (PADH). The occurrence and clinical impact of PADH following severe malaria infections in areas of unstable transmission are unknown. CASE: A 45-year-old Bangladeshi male was initially admitted to a local hospital with severe falciparum malaria complicated by hyperparasitaemia and treated with intravenous artesunate. Twenty days from his first presentation he was readmitted with delayed onset haemolytic anaemia and acute kidney injury. Multiple blood transfusions and haemodialysis were required. Renal biopsy revealed acute tubular injury and haem pigment nephropathy. His haemoglobin and renal function recovered to baseline after 62 days from his second admission. DISCUSSION: This case highlights the differential diagnosis of post-malaria delayed onset haemolysis, including the recently described syndrome of post-artemisinin delayed haemolysis. The pathophysiology contributing to acute kidney injury in this patient and the limited treatment options are discussed. CONCLUSIONS: This report describes PADH complicated by acute kidney injury in an adult patient living in a malaria hypoendemic region who subsequently required blood transfusions and haemodialysis. This case emphasizes the importance of routine follow up of haemoglobin and renal function in artesunate-treated patients who have recovered from severe malaria.

Selfish spermatogonial selection: evidence from an immunohistochemical screen in testes of elderly men.

The dominant congenital disorders Apert syndrome, achondroplasia and multiple endocrine neoplasia-caused by specific missense mutations in the FGFR2, FGFR3 and RET proteins respectively-represent classical examples of paternal age-effect mutation, a class that arises at particularly high frequencies in the sperm of older men. Previous analyses of DNA from randomly selected cadaveric testes showed that the levels of the corresponding FGFR2, FGFR3 and RET mutations exhibit very uneven spatial distributions, with localised hotspots surrounded by large mutation-negative areas. These studies imply that normal testes are mosaic for clusters of mutant cells: these clusters are predicted to have altered growth and signalling properties leading to their clonal expansion (selfish spermatogonial selection), but DNA extraction eliminates the possibility to study such processes at a tissue level. Using a panel of antibodies optimised for the detection of spermatocytic seminoma, a rare tumour of spermatogonial origin, we demonstrate that putative clonal events are frequent within normal testes of elderly men (mean age: 73.3 yrs) and can be classed into two broad categories. We found numerous small (less than 200 cells) cellular aggregations with distinct immunohistochemical characteristics, localised to a portion of the seminiferous tubule, which are of uncertain significance. However more infrequently we identified additional regions where entire seminiferous tubules had a circumferentially altered immunohistochemical appearance that extended through multiple serial sections that were physically contiguous (up to 1 mm in length), and exhibited enhanced staining for antibodies both to FGFR3 and a marker of downstream signal activation, pAKT. These findings support the concept that populations of spermatogonia in individual seminiferous tubules in the testes of older men are clonal mosaics with regard to their signalling properties and activation, thus fulfilling one of the specific predictions of selfish spermatogonial selection.

CD31 angiogenesis and combined expression of HIF-1α and HIF-2α are prognostic in primary clear-cell renal cell carcinoma (CC-RCC), but HIFα transcriptional products are not: implications for antiangiogenic trials and HIFα biomarker studies in primary CC-RCC.

Hypoxia-inducible factors, HIF-1α and HIF-2α, are expressed in the majority of clear-cell renal cell carcinoma (CC-RCC). In vitro, HIFα isoforms regulate a differential set of genes, and their effects in vivo within CC-RCC tumours may affect outcome. The role of angiogenesis and HIFα transcriptional products, including those involved in cell metabolism and morphological dedifferentiation have not been extensively investigated and might have relevance to the development of antiangiogenic or anti-HIFα trials in primary CC-RCC, either before or after radical nephrectomy. We analysed 168 consecutive clear-cell renal tumours from 1983 to 1999 within tissue microarrays and assessed expression of HIF-1α and HIF-2α together with the protein expression of seven of their target genes (BNIP3, CA9, Cyclin D1, GLUT-1, LDH5, Oct-4 and VEGF). The expression of these factors was compared with patient overall survival and CD31 angiogenesis. We found that HIFα antigenicity deteriorated with the age of the paraffin block (P < 0.0001) and in tumours from 1983 to 1992 was deemed not to be reliable. Similar findings were found in aged archival osteosarcoma samples. This might have important implications for retrospective biomarker studies that rely on archival tissue material. HIF-1α(HIGH)/HIF-2α(LOW) tumours had a worse overall survival compared with HIF-1α(LOW)/HIF-2α(LOW) tumours (P = 0.04). Surprisingly, on multivariate analysis, high levels of CD31(+) angiogenesis was shown to be an independent prognostic marker of increased overall survival (P = 0.003). We propose that better differentiation of vascular endothelium may be a reflection of a greater production of vessel stabilization factors versus pro-angiogenic factors, and therefore a less aggressive phenotype.

The role of postmortem studies in pneumonia etiology research.

The diagnosis of etiology in severe pneumonia remains a challenging area. Postmortem lung tissue potentially increases the sensitivity of investigations for identification of causative pathogens in fatal cases of pneumonia and can confirm antemortem microbiological diagnoses. Tissue sampling allows assessment of histological patterns of disease and ancillary immunohistochemical or molecular diagnostic techniques. It may also enhance the recognition of noninfectious conditions that clinically simulate acute pneumonia. Biobanking of lung tissue or postmortem culture isolates offers opportunities for new pathogen discovery and research into host-pathogen interactions. The Pneumonia Etiology Research for Child Health study proposes a percutaneous needle biopsy approach to obtain postmortem samples, rather than a full open autopsy. This has the advantage of greater acceptability to relatives, but risks greater sampling error. Both approaches may be susceptible to microbiological contamination or pathogen degradation. However, previous autopsy studies have confirmed the value of histological examination in revealing unsuspected pathogens and influencing clinical guidelines for the diagnosis and treatment of future pneumonia cases.

Orientia tsutsugamushi in human scrub typhus eschars shows tropism for dendritic cells and monocytes rather than endothelium.

Scrub typhus is a common and underdiagnosed cause of febrile illness in Southeast Asia, caused by infection with Orientia tsutsugamushi. Inoculation of the organism at a cutaneous mite bite site commonly results in formation of a localized pathological skin reaction termed an eschar. The site of development of the obligate intracellular bacteria within the eschar and the mechanisms of dissemination to cause systemic infection are unclear. Previous postmortem and in vitro reports demonstrated infection of endothelial cells, but recent pathophysiological investigations of typhus patients using surrogate markers of endothelial cell and leucocyte activation indicated a more prevalent host leucocyte than endothelial cell response in vivo. We therefore examined eschar skin biopsies from patients with scrub typhus to determine and characterize the phenotypes of host cells in vivo with intracellular infection by O. tsutsugamushi, using histology, immunohistochemistry, double immunofluorescence confocal laser scanning microscopy and electron microscopy. Immunophenotyping of host leucocytes infected with O. tsutsugamushi showed a tropism for host monocytes and dendritic cells, which were spatially related to different histological zones of the eschar. Infected leucocyte subsets were characterized by expression of HLADR+, with an "inflammatory" monocyte phenotype of CD14/LSP-1/CD68 positive or dendritic cell phenotype of CD1a/DCSIGN/S100/FXIIIa and CD163 positive staining, or occasional CD3 positive T-cells. Endothelial cell infection was rare, and histology did not indicate a widespread inflammatory vasculitis as the cause of the eschar. Infection of dendritic cells and activated inflammatory monocytes offers a potential route for dissemination of O. tsutsugamushi from the initial eschar site. This newly described cellular tropism for O. tsutsugamushi may influence its interaction with local host immune responses.

Laparoscopic high-intensity focused ultrasound for renal tumours: a proof of concept study.

UNLABELLED: Study Type--Therapy (case series) Level of Evidence What's known on the subject? and What does the study add? Renal cancer is increasingly diagnosed when tumours are small and asymptomatic, during routine abdominal imaging. Whilst surgery is an effective and potentially curative option, it carries a significant risk of complications. Recent work suggests that thermally ablative therapies (RFA, cryotherapy, HIFU) may be suitable minimally invasive treatment options in selected patients. The success of extracorporeal HIFU has been limited by the abdominal wall and rib-cage limiting energy delivery. For this study, a purpose-built laparoscopic HIFU probe was designed to allow direct application of the transducer to the tumour surface, thus facilitating tumour destruction. Successful and accurate tumour destruction was demonstrated, paving the way for further clinical trials, subject to device modifications. OBJECTIVE: • To test and establish clinical proof of concept for a laparoscopic high-intensity focused ultrasound (HIFU) device that facilitates delivery of ultrasound by direct application of a probe to the tumour surface. PATIENTS AND METHODS: • Twelve patients with renal tumours were treated with laparoscopic HIFU using a newly designed probe inserted via an 18-mm laparoscopic port. • HIFU treatment was targeted at a pre-defined proportion of the tumour and immediate laparoscopic partial or radical nephrectomy was then performed. RESULTS: • No tumour ablation was seen in the first five patients which made modifications in the treatment protocol necessary. After this, definite histological evidence of ablation was seen in the remaining seven patients. • The ablated zones were within the targeted area in all patients and no intra-lesional skipping was seen. • Subcapsular skipping was seen at the probe-tumour interface in two patients with viable tumour cells seen at microscopy. • One patient did not undergo surgical extirpation; subsequent biopsy revealed no viable tumour cells. • There were no intraoperative or postoperative complications directly related to HIFU therapy and patients have reached a mean (range) follow-up of 15 (8-24) months with no evidence of metastatic disease or late complications. CONCLUSIONS: • Tumour ablation with laparoscopic HIFU is feasible. • Homogenous ablation can be achieved with no vital tissue within the targeted zone. • The technique is associated with low morbidity and may have a role in the definitive management of small tumours.

Coma in fatal adult human malaria is not caused by cerebral oedema.

BACKGROUND: The role of brain oedema in the pathophysiology of cerebral malaria is controversial. Coma associated with severe Plasmodium falciparum malaria is multifactorial, but associated with histological evidence of parasitized erythrocyte sequestration and resultant microvascular congestion in cerebral vessels. To determine whether these changes cause breakdown of the blood-brain barrier and resultant perivascular or parenchymal cerebral oedema, histology, immunohistochemistry and image analysis were used to define the prevalence of histological patterns of oedema and the expression of specific molecular pathways involved in water balance in the brain in adults with fatal falciparum malaria. METHODS: The brains of 20 adult Vietnamese patients who died of severe malaria were examined for evidence of disrupted vascular integrity. Immunohistochemistry and image analysis was performed on brainstem sections for activation of the vascular endothelial growth factor (VEGF) receptor 2 and expression of the aquaporin 4 (AQP4) water channel protein. Fibrinogen immunostaining was assessed as evidence of blood-brain barrier leakage and perivascular oedema formation. Correlations were performed with clinical, biochemical and neuropathological parameters of severe malaria infection. RESULTS: The presence of oedema, plasma protein leakage and evidence of VEGF signalling were heterogeneous in fatal falciparum malaria and did not correlate with pre-mortem coma. Differences in vascular integrity were observed between brain regions with the greatest prevalence of disruption in the brainstem, compared to the cortex or midbrain. There was a statistically non-significant trend towards higher AQP4 staining in the brainstem of cases that presented with coma (P = .02). CONCLUSIONS: Histological evidence of cerebral oedema or immunohistochemical evidence of localised loss of vascular integrity did not correlate with the occurrence of pre-mortem coma in adults with fatal falciparum malaria. Enhanced expression of AQP4 water channels in the brainstem may, therefore, reflect a mix of both neuropathological or attempted neuroprotective responses to oedema formation.

OCT2, SSX and SAGE1 reveal the phenotypic heterogeneity of spermatocytic seminoma reflecting distinct subpopulations of spermatogonia.

Spermatocytic seminoma (SS) is a rare testicular neoplasm that occurs predominantly in older men. In this study, we aimed to shed light on the histogenesis of SS by investigating the developmental expression of protein markers that identify distinct subpopulations of human spermatogonia in the normal adult testis. We analysed the expression pattern of OCT2, SSX2-4, and SAGE1 in 36 SS cases and four intratubular SS (ISS) as well as a series of normal testis samples throughout development. We describe for the first time two different types of SS characterized by OCT2 or SSX2-4 immunoexpression. These findings are consistent with the mutually exclusive antigenic profile of these markers during different stages of testicular development and in the normal adult testis. OCT2 was expressed predominantly in A(dark) spermatogonia, SSX2-4 was present in A(pale) and B spermatogonia and leptotene spermatocytes, whilst SAGE1 was exclusively present in a subset of post-pubertal germ cells, most likely B spermatogonia. The presence of OCT2 and SSX2-4 in distinct subsets of germ cells implies that these markers represent germ cells at different maturation stages. Analysis of SAGE1 and SSX2-4 in ISS showed spatial differences suggesting ongoing maturation of germ cells during progression of SS tumourigenesis. We conclude that the expression pattern of OCT2, SSX2-4, and SAGE1 supports the origin of SS from spermatogonia and provides new evidence for heterogeneity of this tumour, potentially linked either to the cellular origin of SS or to partial differentiation during tumour progression, including a hitherto unknown OCT2-positive variant of the tumour likely derived from A(dark) spermatogonia.

Aberrant succination of proteins in fumarate hydratase-deficient mice and HLRCC patients is a robust biomarker of mutation status.

Germline mutations in the FH gene encoding the Krebs cycle enzyme fumarate hydratase predispose to hereditary leiomyomatosis and renal cell cancer (HLRCC) syndrome. FH-deficient cells and tissues accumulate high levels of fumarate, which may act as an oncometabolite and contribute to tumourigenesis. A recently proposed role for fumarate in the covalent modification of cysteine residues to S-(2-succinyl) cysteine (2SC) (termed protein succination) prompted us to assess 2SC levels in our existing models of HLRCC. Herein, using a previously characterized antibody against 2SC, we show that genetic ablation of FH causes high levels of protein succination. We next hypothesized that immunohistochemistry for 2SC would serve as a metabolic biomarker for the in situ detection of FH-deficient tissues. Robust detection of 2SC was observed in Fh1 (murine FH)-deficient renal cysts and in a retrospective series of HLRCC tumours (n = 16) with established FH mutations. Importantly, 2SC was undetectable in normal tissues (n = 200) and tumour types not associated with HLRCC (n = 1342). In a prospective evaluation of cases referred for genetic testing for HLRCC, the presence of 2SC-modified proteins (2SCP) correctly predicted genetic alterations in FH in every case. In two series of unselected type II papillary renal cancer (PRCC), prospectively analysed by 2SCP staining followed by genetic analysis, the biomarker accurately identified previously unsuspected FH mutations (2/33 and 1/36). The investigation of whether metabolites in other tumour types produce protein modification signature(s) that can be assayed using similar strategies will be of interest in future studies of cancer.

Serial analysis of resected prostate cancer suggests up-regulation of type 1 IGF receptor with disease progression.

OBJECTIVE: • To compare immunostaining protocols using different antibodies for the type 1 insulin-like growth factor receptor (IGF-1R) in channel transurethal resection of the prostate (chTURP) chips, and to investigate how IGF-1R expression varies with time in serial prostate cancer specimens from individual patients. METHODS: • We studied IGF-1R expression in 44 prostate cancer specimens from 18 patients who had undergone serial chTURP at least 3 months apart. • Retrospective analysis of the hospital notes was undertaken to obtain clinical information, including age, Gleason score, prostate-specific antigen (PSA) level, hormone treatment and metastatic disease status at the time of each operation. • After an optimization process using three commercially-available IGF-1R antibodies, we used two antibodies for semiquantititve immunostaining of serial chTURP chips. RESULTS: • Santa Cruz antibody sc713 gave positive staining in IGF-1R null R- cells, and was not used further. Antibodies from Cell Signaling Technology (Beverly, MA, USA) (CS) and NeoMarkers Inc. (Fremont, CA, USA) (NM) did not stain R- cells and, in prostate tissue, showed staining of the glandular epithelium, with negligible stromal staining. All 44 chTURP samples contained identifiable malignant tissue and, of these, 73% and 64% scored moderately or strongly (score 3 or 4) with the CS and NM antibodies respectively. • There was significant correlation of IGF-1R scores of malignant tissue between the two antibodies (P < 0.001). By contrast, staining of benign glands showed poor correlation between antibodies: CS gave significantly weaker staining than malignant epithelium in the same sections (P < 0.001), whereas NM showed poor discrimination between malignant and benign glands. IGF-1R staining scores generated by the CS antibody were used to analyze the clinical data. • Most patients (six of seven) with falling IGF-1R staining scores were responding to androgen deprivation therapy (confirmed by PSA response) between operations. Conversely, in seven of eight patients who had progression to androgen-independence between procedures, IGF-1R levels increased or remained high. Finally, seven of 11 patients who developed radiologically confirmed metastases between procedures showed stable or increasing IGF-1R staining scores. CONCLUSION: • The present study is the first to assess changes in IGF-1R expression in serial prostate cancer samples. The results obtained indicate that IGF-1R expression usually remains high throughout the course of histologically-proven disease progression in serial specimens, suggesting that the IGF-1R remains a valid treatment target for advanced prostate cancer.

Type 1 insulin-like growth factor receptor translocates to the nucleus of human tumor cells.

The type 1 insulin-like growth factor receptor (IGF-1R) is a transmembrane glycoprotein composed of two extracellular alpha subunits and two beta subunits with tyrosine kinase activity. The IGF-1R is frequently upregulated in cancers and signals from the cell surface to promote proliferation and cell survival. Recent attention has focused on the IGF-1R as a target for cancer treatment. Here, we report that the nuclei of human tumor cells contain IGF-1R, detectable using multiple antibodies to alpha- and beta-subunit domains. Cell-surface IGF-1R translocates to the nucleus following clathrin-mediated endocytosis, regulated by IGF levels. The IGF-1R is unusual among transmembrane receptors that undergo nuclear import, in that both alpha and beta subunits traffic to the nucleus. Nuclear IGF-1R is phosphorylated in response to ligand and undergoes IGF-induced interaction with chromatin, suggesting direct engagement in transcriptional regulation. The IGF dependence of these phenomena indicates a requirement for the receptor kinase, and indeed, IGF-1R nuclear import and chromatin binding can be blocked by a novel IGF-1R kinase inhibitor. Nuclear IGF-1R is detectable in primary renal cancer cells, formalin-fixed tumors, preinvasive lesions in the breast, and nonmalignant tissues characterized by a high proliferation rate. In clear cell renal cancer, nuclear IGF-1R is associated with adverse prognosis. Our findings suggest that IGF-1R nuclear import has biological significance, may contribute directly to IGF-1R function, and may influence the efficacy of IGF-1R inhibitory drugs.

Induction of the vascular endothelial growth factor pathway in the brain of adults with fatal falciparum malaria is a non-specific response to severe disease.

AIMS: Pathological or neuroprotective mechanisms in the brain in severe malaria may arise from microvascular obstruction with malaria-parasitized erythrocytes. This study aimed to investigate the role of hypoxia and induction of the vascular endothelial growth factor (VEGF) pathway in the neuropathophysiology of severe malaria. METHODS AND RESULTS: Immunohistochemistry was performed on post mortem brain tissue sections from 20 cases of severe malaria and examined for the expression of transcriptional regulators of VEGF [hypoxia-inducible factor-1 alpha (HIF-1alpha), HIF-2alpha], DEC-1, VEGF, VEGF receptors 1 and 2, and the activated, phosphorylated VEGF receptor 2 (pKDR). HIFs showed limited protein expression and/or translocation to cell nuclei in severe malaria, but DEC-1, which is more stable and regulated by HIF-1alpha, was observed. There was heterogeneous expression of VEGF and its receptors in severe malaria and non-malarial disease controls. pKDR expression on vessels was greater in malaria cases than in controls but did not correlate with parasite sequestration. VEGF uptake by malaria parasites was observed. CONCLUSIONS: VEGF and its receptor expression levels in severe malaria reflect a non-specific response to severe systemic disease. Potential manipulation of events at the vasculature by the parasite requires further investigation.