Spatial navigation impairment is proportional to right hippocampal volume

Cognitive deficits in older adults attributable to Alzheimer's disease (AD) pathology are featured early on by hippocampal impairment. Among these individuals, deterioration in spatial navigation, manifested by poor hippocampus-dependent allocentric navigation, may occur well before the clinical onset of dementia. Our aim was to determine whether allocentric spatial navigation impairment would be proportional to right hippocampal volume loss irrespective of general brain atrophy. We also contrasted the respective spatial navigation scores of the real-space human Morris water maze with its corresponding 2D computer version. We included 42 cognitively impaired patients with either amnestic mild cognitive impairment (n = 23) or mild and moderate AD (n = 19), and 14 cognitively intact older controls. All participants underwent 1.5T MRI brain scanning with subsequent automatic measurement of the total brain and hippocampal (right and left) volumes. Allocentric spatial navigation was tested in the real-space version of the human Morris water maze and in its corresponding computer version. Participants used two navigational cues to locate an invisible goal independent of the start position. We found that smaller right hippocampal volume was associated with poorer navigation performance in both the real-space (β = -0.62, P < 0.001) and virtual (β = -0.43, P = 0.026) versions, controlling for demographic variables, total brain and left hippocampal volumes. In subsequent analyses, the results were significant in cognitively impaired (P ≤ 0.05) but not in cognitively healthy (P > 0.59) subjects. The respective real-space and virtual scores strongly correlated with each other. Our findings indicate that the right hippocampus plays a critical role in allocentric navigation, particularly when cognitive impairment is present.     

Collaborative interplay between FGF-2 and VEGF-C promotes lymphangiogenesis and metastasis

Interplay between various lymphangiogenic factors in promoting lymphangiogenesis and lymphatic metastasis remains poorly understood. Here we show that FGF-2 and VEGF-C, two lymphangiogenic factors, collaboratively promote angiogenesis and lymphangiogenesis in the tumor microenvironment, leading to widespread pulmonary and lymph-node metastases. Coimplantation of dual factors in the mouse cornea resulted in additive angiogenesis and lymphangiogenesis. At the molecular level, we showed that FGFR-1 expressed in lymphatic endothelial cells is a crucial receptor that mediates the FGF-2–induced lymphangiogenesis. Intriguingly, the VEGFR-3–mediated signaling was required for the lymphatic tip cell formation in both FGF-2– and VEGF-C–induced lymphangiogenesis. Consequently, a VEGFR-3–specific neutralizing antibody markedly inhibited FGF-2–induced lymphangiogenesis. Thus, the VEGFR-3–induced lymphatic endothelial cell tip cell formation is a prerequisite for FGF-2–stimulated lymphangiogenesis. In the tumor microenvironment, the reciprocal interplay between FGF-2 and VEGF-C collaboratively stimulated tumor growth, angiogenesis, intratumoral lymphangiogenesis, and metastasis. Thus, intervention and targeting of the FGF-2– and VEGF-C–induced angiogenic and lymphangiogenic synergism could be potentially important approaches for cancer therapy and prevention of metastasis.     

Inactivation of polycomb repressive complex 2 components in myeloproliferative and myelodysplastic/myeloproliferative neoplasms

The polycomb repressive complex 2 (PRC2) is a highly conserved histone H3 lysine 27 methyltransferase that regulates the expression of developmental genes. Inactivating mutations of the catalytic component of PRC2, EZH2, are seen in myeloid disorders. We reasoned that the other 2 core PRC2 components, SUZ12 and EED, may also be mutational targets in these diseases, as well as associated factors such as JARID2. SUZ12 mutations were identified in 1 of 2 patients with myelodysplastic syndrome/myeloproliferative neoplasms with 17q acquired uniparental disomy and in 2 of 2 myelofibrosis cases with focal 17q11 deletions. All 3 were missense mutations affecting the highly conserved VEFS domain. Analysis of a further 146 myelodysplastic syndrome/myeloproliferative neoplasm patients revealed an additional VEFS domain mutant, yielding a total mutation frequency of 1.4% (2 of 148). We did not find mutations of JARID2 or EED in association with acquired uniparental disomy for chromosome 6p or 11q, respectively; however, screening unselected cases identified missense mutations in EED (1 of 148; 1%) and JARID2 (3 of 148; 2%). All 3 SUZ12 mutations tested and the EED mutation reduced PRC2 histone methyltransferase activity in vitro, demonstrating that PRC2 function may be compromised in myeloid disorders by mutation of distinct genes.     

Markedly asymmetric presentation in multiple system atrophy

BackgroundMultiple system atrophy (MSA) presents with fairly symmetrical, levodopa unresponsive parkinsonism and additional features like autonomic dysfunction, cerebellar and corticospinal tract involvement. Marked asymmetry in atypical parkinsonism suggests alternative diagnosis like Corticobasal syndrome (CBS).MethodsWe describe five unusual cases, who presented initially with markedly asymmetric parkinsonism, rigid dystonic abnormal limb posturing and subsequently developed clinical and/or radiological features consistent with probable MSA-P.ResultsUsing the internationally accepted diagnostic criteria, the patients fulfilled the diagnostic criteria for probable MSA-P after 5 years from disease onset. Case 4 and 5 had characteristic MRI features and Case 2 was pathologically confirmed.ConclusionsWe use these cases to highlight that MSA-P MSA-P can present rarely with very marked asymmetry, dystonic limb and myoclonic jerks leading to a diagnosis of CBS at onset.