TY  - JOUR
A1  - Hopp, Sarah
A1  - Albert-Weissenberger, Christiane
A1  - Mencl, Stine
A1  - Bieber, Michael
A1  - Schuhmann, Michael K.
A1  - Stetter, Christian
A1  - Nieswandt, Bernhard
A1  - Schmidt, Peter M.
A1  - Monoranu, Camelia-Maria
A1  - Alafuzoff, Irina
A1  - Marklund, Niklas
A1  - Nolte, Marc W.
A1  - Sirén, Anna-Leena
A1  - Kleinschnitz, Christoph
T1  - Targeting coagulation factor XII as a novel therapeutic option in brain trauma
JF  - Annals of Neurology
N2  - Objective: 
Traumatic brain injury is a major global public health problem for which specific therapeutic interventions are lacking. There is, therefore, a pressing need to identify innovative pathomechanism-based effective therapies for this condition. Thrombus formation in the cerebral microcirculation has been proposed to contribute to secondary brain damage by causing pericontusional ischemia, but previous studies have failed to harness this finding for therapeutic use. The aim of this study was to obtain preclinical evidence supporting the hypothesis that targeting factor XII prevents thrombus formation and has a beneficial effect on outcome after traumatic brain injury. 

Methods: 
We investigated the impact of genetic deficiency of factor XII and acute inhibition of activated factor XII with a single bolus injection of recombinant human albumin-fused infestin-4 (rHA-Infestin-4) on trauma-induced microvascular thrombus formation and the subsequent outcome in 2 mouse models of traumatic brain injury. 

Results: 
Our study showed that both genetic deficiency of factor XII and an inhibition of activated factor XII in mice minimize trauma-induced microvascular thrombus formation and improve outcome, as reflected by better motor function, reduced brain lesion volume, and diminished neurodegeneration. Administration of human factor XII in factor XII-deficient mice fully restored injury-induced microvascular thrombus formation and brain damage. 

Interpretation: 
The robust protective effect of rHA-Infestin-4 points to a novel treatment option that can decrease ischemic injury after traumatic brain injury without increasing bleeding tendencies.
KW  - Molecular-weight heparin
KW  - Thrombus formation
KW  - Cerebral-ischemia
KW  - in-vivo
KW  - Intravascular coagulation
KW  - Hemodynamic depression
KW  - Head-injury
KW  - Rats
KW  - Model
KW  - Mice
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-188800
VL  - 79
IS  - 6
ER  - 
TY  - JOUR
A1  - Sirén, Anna-Leena
A1  - Stetter, Christian
A1  - Hirschberg, Markus
A1  - Nieswandt, Bernhard
A1  - Ernestus, Ralf-Ingo
A1  - Heckmann, Manfred
T1  - An experimental protocol for in vivo imaging of neuronal structural plasticity with 2-photon microscopy in mice
JF  - Experimental & Translational Stroke Medicine
N2  - Introduction

Structural plasticity with synapse formation and elimination is a key component of memory capacity and may be critical for functional recovery after brain injury. Here we describe in detail two surgical techniques to create a cranial window in mice and show crucial points in the procedure for long-term repeated in vivo imaging of synaptic structural plasticity in the mouse neocortex.

Methods

Transgenic Thy1-YFP(H) mice expressing yellow-fluorescent protein (YFP) in layer-5 pyramidal neurons were prepared under anesthesia for in vivo imaging of dendritic spines in the parietal cortex either with an open-skull glass or thinned skull window. After a recovery period of 14 days, imaging sessions of 45–60 min in duration were started under fluothane anesthesia. To reduce respiration-induced movement artifacts, the skull was glued to a stainless steel plate fixed to metal base. The animals were set under a two-photon microscope with multifocal scanhead splitter (TriMScope, LaVision BioTec) and the Ti-sapphire laser was tuned to the optimal excitation wavelength for YFP (890 nm). Images were acquired by using a 20×, 0.95 NA, water-immersion objective (Olympus) in imaging depth of 100–200 μm from the pial surface. Two-dimensional projections of three-dimensional image stacks containing dendritic segments of interest were saved for further analysis. At the end of the last imaging session, the mice were decapitated and the brains removed for histological analysis.

Results

Repeated in vivo imaging of dendritic spines of the layer-5 pyramidal neurons was successful using both open-skull glass and thinned skull windows. Both window techniques were associated with low phototoxicity after repeated sessions of imaging.

Conclusions

Repeated imaging of dendritic spines in vivo allows monitoring of long-term structural dynamics of synapses. When carefully controlled for influence of repeated anesthesia and phototoxicity, the method will be suitable to study changes in synaptic structural plasticity after brain injury.
KW  - 2-photon microscopy
KW  - Fluorescence
KW  - In vivo imaging
KW  - Neurons
KW  - Cranial window
KW  - Mouse model
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-96908
UR  - http://www.etsmjournal.com/content/5/1/9
ER  -