In vitro exposure of neural progenitor cell (NPC) populations to reduced O2 (e.g. 3% versus 20%) can increase their proliferation, survival and neuronal differentiation. Our objective was to determine if an acute (<1 hr), in vivo exposure to intermittent hypoxia (AIH) alters expansion and/or differentiation of subsequent in vitro cultures of NPC from the subventricular zone (SVZ). Neonatal C57BL/6 mice (postnatal day 4) were exposed to an AIH paradigm (20×1 minute; alternating 21% and 10% O2). Immediately after AIH, SVZ tissue was isolated and NPC populations were cultured and assayed either as neurospheres (NS) or as adherent monolayer cells (MASC). AIH markedly increased the capacity for expansion of cultured NS and MASC, and this was accompanied by increases in a proliferation maker (Ki67), MTT activity and hypoxia-inducible factor-1α (HIF-1α) signaling in NS cultures. Peptide blockade experiments confirmed that proteins downstream of HIF-1α are important for both proliferation and morphological changes associated with terminal differentiation in NS cultures. Finally, immunocytochemistry and Western blotting experiments demonstrated that AIH increased expression of the neuronal fate determination transcription factor Pax6 in SVZ tissue, and this was associated with increased neuronal differentiation in cultured NS and MASC. We conclude that in vivo AIH exposure can enhance the viability of subsequent in vitro SVZ-derived NPC cultures. AIH protocols may therefore provide a means to “prime” NPC prior to transplantation into the injured central nervous system.

Cervical spinal cord injury (cSCI) disrupts bulbospinal projections to motoneurons controlling the upper limbs, resulting in significant functional impairments. Ongoing clinical and experimental research has revealed several lines of evidence for functional neuroplasticity and recovery of upper extremity function after SCI. The underlying neural substrates, however, have not been thoroughly characterized. The goals of the present study were to map the intraspinal motor circuitry associated with a defined upper extremity muscle, and evaluate chronic changes in the distribution of this circuit following incomplete cSCI. Injured animals received a high cervical (C2) lateral hemisection (Hx), which compromises supraspinal input to ipsilateral spinal motoneurons controlling the upper extremities (forelimb) in the adult rat. A battery of behavioral tests was used to characterize the time course and extent of forelimb motor recovery over a 16 week period post-injury. A retrograde transneuronal tracer -pseudorabies virus -was used to define the motor and pre-motor circuitry controlling the extensor carpi radialis longus (ECRL) muscle in spinal intact and injured animals. In the spinal intact rat, labeling was observed unilaterally within the ECRL motoneuron pool and within spinal interneurons bilaterally distributed within the dorsal horn and intermediate gray matter. No changes in labeling were observed 16 weeks post-injury, despite a moderate degree of recovery of forelimb motor function. These results suggest that recovery of the forelimb function assessed following C2Hx injury does not involve recruitment of new interneurons into the ipsilateral ECRL motor pathway. However, the functional significance of these existing interneurons to motor recovery requires further exploration.

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Pulmonary arterial hypertension has been reported with a prevalence of 7.9% in patients with anti-synthetase syndrome; however, anti-synthetase syndrome associated with pulmonary veno-occlusive disease (PVOD) has never before been described in the literature. We present a novel case of anti-synthetase syndrome-associated PVOD in a patient who presented with hypoxic respiratory failure associated with right heart failure and was diagnosed with anti-synthetase syndrome based on his autoimmune serology and pre-capillary pulmonary hypertension on right heart catheterization. He was initiated on pulmonary arterial hypertension therapy, but with escalating dose of parenteral epoprostenol, experienced acute clinical worsening with chest imaging concerning for PVOD that was confirmed on autopsy. Anti-synthetase syndrome can be associated with PVOD, and it should be suspected in patients who have evidence of pre-capillary pulmonary hypertension and who deteriorate with the initiation of pulmonary hypertension-specific therapy.

Introduction Motor dysfunction and muscle atrophy are well-documented in the lower extremity following spinal cord injury. However the extent and time course of myoplastic changes in forelimb musculature is not clear. Methods Forelimb muscle morphology and fiber type were evaluated following high cervical hemi-lesion injury in rats. Results There was significant atrophy of the ipsilateral extensor carpi radialis longus (ECRL) muscle 2 weeks post-injury, which was subsequently reversed at 8 weeks post-injury. The triceps muscle showed minimal evidence of atrophy following spinal injury. No significant changes in fiber type were observed. Discussion These findings indicate a robust capacity for spontaneous myoplasticity following C2 hemisection injury but highlight differential capacity for plasticity within the forelimb muscles.