Evaluation of the presence and distribution of leptomeningeal inflammation in SIDS/SUDI cases and comparison with a hospital-based cohort.

INTRODUCTION: Prior research demonstrates that leptomeninges of infants and late-term fetuses derived from a non-traumatic, hospital-based cohort contain a surprisingly large number of inflammatory cells and stainable iron. These were present irrespective of the findings from the general autopsy, the neuropathologic examination, and the mode of delivery. MATERIALS AND METHODS: We applied a similar methodology to a sudden infant death syndrome/sudden unexpected death in infancy (SIDS/SUDI) cohort. Forty-two SIDS/SUDI cases autopsied between 2006 and 2014 by the San Diego County Medical Examiner's Office were identified. An interpretable amount of leptomeninges from at least two areas of the brain (cerebral cortex, brain stem, cerebellum) were present in each case. Immunoperoxidase (IPOX) staining with CD45 and CD68 was performed and Perl's method was used to detect the presence of iron. The number of immunoreactive cells per IPOX stain within the leptomeninges in each slide was manually tabulated and the density subsequently quantified. The presence or absence of stainable iron was noted. RESULTS: This cohort represented 22 males and 20 females ranging in age from 2 to 311 days, with relatively evenly divided modes of delivery. The examined brain sections included 32 of the cerebral cortex, 18 of the brain stem, and 36 of the cerebellum. The lengths of the examined leptomeninges ranged from 2 to 40 mm. The ranges of the number of cells per millimeter, and the standard deviations of the means were wide and varied. Overall, there was no significant difference in the number of CD45 or CD68 immunoreactive cells/millimeter between the three brain sites. Comparing this cohort to a subpopulation of hospitalized infants in our prior study, there were no significant differences between the density of inflammatory cells in the sections from the cerebral cortex and brain stem. There were differences in the CD68 densities, particularly in the cerebellar sections which may be attributable to methodological differences. Iron was identified in only a single section in this cohort but was present in most of the cases in the hospital-based cohort. CONCLUSION: This study further elucidates the relevance of the presence of inflammatory cells and iron in the leptomeninges. Whether in a hospital-based or more forensically relevant population, the presence of inflammatory cells in the leptomeninges (even in great abundance) is common.

The inflammatory cellular constituents of foetal and infant leptomeninges: a survey of hospital-based autopsies without trauma.

OBJECTIVES: Notwithstanding the lack of definitive evidence from studies conducted to date, inflammatory infiltrates and iron deposition in the leptomeninges are routinely used as forensic markers of traumatic brain injury. We investigated the presence of these forensic markers of trauma in neonates and infants, with the objective of determining their suitability for use in forensic cases. METHODS: Leptomeninges derived from non-traumatic deaths were studied. Thirty-three cases were divided into groups 1 and 2, according to set age groups. Inflammatory cells and iron in these groups were quantified. RESULTS: CD45, CD68 and CD163 positive inflammatory cells were identified in the leptomeninges of sections of the cerebellum, brain stem and cortex of all 33 cases of non-traumatic infant deaths surveyed in this study. There were no significant differences between the two groups. Iron was found in the leptomeninges in several cases, even those without recent haemorrhage. Overall within the two subgroups, the numbers of inflammatory cells and iron containing cells were not significantly different. CONCLUSION: These findings demonstrate that inflammatory cells and iron in the leptomeninges can be found in natural and non-traumatic conditions. Further, two cases with no reported neuropathology demonstrated the presence of inflammatory cells and iron. Thus, cautious interpretation of the presence of inflammatory cells and iron containing cells in forensic paediatric cases is recommended.

Hedgehog-responsive candidate cell of origin for diffuse intrinsic pontine glioma.

Diffuse intrinsic pontine gliomas (DIPGs) are highly aggressive tumors of childhood that are almost universally fatal. Our understanding of this devastating cancer is limited by a dearth of available tissue for study and by the lack of a faithful animal model. Intriguingly, DIPGs are restricted to the ventral pons and occur during a narrow window of middle childhood, suggesting dysregulation of a postnatal neurodevelopmental process. Here, we report the identification of a previously undescribed population of immunophenotypic neural precursor cells in the human and murine brainstem whose temporal and spatial distributions correlate closely with the incidence of DIPG and highlight a candidate cell of origin. Using early postmortem DIPG tumor tissue, we have established in vitro and xenograft models and find that the Hedgehog (Hh) signaling pathway implicated in many developmental and oncogenic processes is active in DIPG tumor cells. Modulation of Hh pathway activity has functional consequences for DIPG self-renewal capacity in neurosphere culture. The Hh pathway also appears to be active in normal ventral pontine precursor-like cells of the mouse, and unregulated pathway activity results in hypertrophy of the ventral pons. Together, these findings provide a foundation for understanding the cellular and molecular origins of DIPG, and suggest that the Hh pathway represents a potential therapeutic target in this devastating pediatric tumor.

Low CD27 expression in plasma cell dyscrasias correlates with high-risk disease: an immunohistochemical analysis.

Genome-wide expression studies using complementary DNA microarrays recently suggested a number of intriguing candidate genes for distinguishing plasma cell dyscrasias. Our objective was to test select markers using immunohistochemical analysis and a tissue microarray from paraffin-embedded bone marrow core biopsy specimens obtained from 8 patients with monoclonal gammopathy of undetermined significance, 17 with plasmacytoma, 160 with multiple myeloma, and 15 with plasma cell leukemia (PCL). We immunostained serial sections for CD138, CD27, CD56, p27, Ki-67, CD3, and CD20. Each core was scored in duplicate by observers blinded to phenotype and reported as the average percentage of CD138+ cells. The Mann-Whitney U test was used to determine significance between groups. PCL showed significantly less immunostaining for CD27 (P < .01) and p27 (P < .05) compared with plasmacytoma and multiple myeloma. Low CD27 expression also was associated with plasmacytoma progression to multiple myeloma (P <.05). Our results support the hypothesis that low CD27 expression correlates with high-risk disease, including primary PCL and decreased progression-free survival in solitary plasmacytoma.

alpha(v)beta(3) Integrin in central nervous system tumors.

alpha(v)beta(3) Is an integrin specifically expressed in endothelial cells of newly forming blood vessels. Integrin-mediated angiogenesis is hypothesized to play a central role in the development and the progression of central nervous system neoplasms. Accordingly, it is considered a potential target for antiangiogenic therapy. In the current study, we compare the expression of alpha(v)beta(3) in ependymomas, oligodendrogliomas, pilocytic astrocytomas, medulloblastomas, and vestibular schwannomas (acoustic neuromas). Samples of 5 tumors of each of the 5 tumor types were harvested surgically and frozen. After the pathological diagnosis was confirmed, immunohistochemistry was performed using an anti- alpha(v)beta(3) monoclonal antibody (LM609). The expression of alpha(v)beta(3) was assessed using a 4-tiered (0-3) grading scheme reflecting the percentage of positively staining vessels. All vestibular schwannomas demonstrated strong (grade 3) alpha(v)beta(3) expression. The expression was uniformly prominent in Antoni B regions of the tumors. Of 5 ependymomas, 4 demonstrated uniformly strong alpha(v)beta(3). Oligodendrogliomas, medulloblastomas, and pilocytic astrocytomas demonstrated more variable alpha(v)beta(3). alpha(v)beta(3) may contribute significantly to angiogenesis in vestibular schwannomas and ependymomas. Despite the high vascular density of oligodendrogliomas, pilocytic astrocytomas, and medulloblastomas, these tumors had variable moderate alpha(v)beta(3) expression. This discrepancy suggests temporal and/or regional variability in the angiogenesis in these types of tumor. This study provides the first demonstration of alpha(v)beta(3) expression in vestibular schwannomas, medulloblastomas, and pilocytic astrocytomas.

Burden of neurodegenerative diseases in a cohort of medical examiner subjects.

Here we report studies of the burden of neurodegenerative neuropathologies in a cohort of Medical Examiner (ME) subjects from the County of Santa Clara (California) to determine if this unique population of decedents manifested evidence of neurodegeneration that might underlie causes of death seen in an ME practice. We found that 13% of the brains from ME cases showed significant tau pathology, including 55% of those 65 years old and older and 63% of those 70 years old and older. The histochemical and immunohistochemical findings were consistent with Alzheimer's disease (AD) in 7 subjects and frontotemporal lobar degeneration (FTLD) tauopathy type in six cases. There were no cases of Parkinson's disease, dementia with Lewy Bodies or other neurodegenerative conditions. Our study suggests that decedents >65 years of age in an ME practice are afflicted by common causes of dementia such as AD and FTLD which could contribute wholly or in part to their causes of death.

Characterization of the integrin alpha v beta3 in arteriovenous malformations and cavernous malformations.

BACKGROUND: Alpha V beta 3 (alphavbeta3) is an integrin specifically expressed on the endothelial cells of central nervous system (CNS) neoplasms. However, no data exist on the expression of alphavbeta3 in vascular malformations of the CNS. In this study, we investigate the expression of alphavbeta3 in arteriovenous malformations (AVMs) and cavernous malformations (CMs). METHOD: Frozen samples of AVMs from 12 patients and CMs from 5 patients were obtained intraoperatively. Once the final pathology had been confirmed, immunohistochemistry was performed using an antibody to the integrin alphavbeta3. The alphavbeta3 expression pattern was graded according to the percentage of positively staining vessels. RESULTS: Ten of 12 AVMs demonstrated alphavbeta3 immunopositivity. Six of these 10 AVMs had moderate or strong staining. Most notably, 5 of the 6 moderate or strongly staining AVMs came from patients 22 years of age or younger. Four of these 6 AVMs had previously been embolized. None of the cavernous malformations demonstrated alphavbeta3 immunopositivity. DISCUSSION: alphavbeta3 may contribute to the formation of AVMs in younger patients. alphavbeta3 may also provide a potential therapeutic target. The lack of alphavbeta3 expression in cavernous malformations, despite their high vascular densities, suggests that the pathophysiology of their formation differs from that of AVMs.