Spinal Muscular Atrophy (SMA) is due to the loss of the survival motor neuron gene 1 (SMN1), resulting in motor neuron (MN) degeneration, muscle atrophy and loss of motor function. While SMN2 encodes ...a protein identical to SMN1, a single nucleotide difference in exon 7 causes most of the SMN2-derived transcripts to be alternatively spliced resulting in a truncated and unstable protein (SMNΔ7). SMA patients retain at least one SMN2 copy, making it an important target for therapeutics. Many of the existing SMA models are very severe, with animals typically living less than 2 weeks. Here, we present a novel intermediate mouse model of SMA based upon the human genomic SMN2 gene. Genetically, this model is similar to the well-characterized SMNΔ7 model; however, we have manipulated the SMNΔ7 transgene to encode a modestly more functional protein referred to as SMN read-through (SMN(RT)). By introducing the SMN(RT) transgene onto the background of a severe mouse model of SMA (SMN2(+/+);Smn(-/-)), disease severity was significantly decreased based upon a battery of phenotypic parameters, including MN pathology and a significant extension in survival. Importantly, there is not a full phenotypic correction, allowing for the examination of a broad range of therapeutics, including SMN2-dependent and SMN-independent pathways. This novel animal model serves as an important biological and therapeutic model for less severe forms of SMA and provides an in vivo validation of the SMN(RT) protein.
Late-infantile neuronal ceroid lipofuscinosis (CLN2 disease) is a hereditary neurological disorder characterized by progressive retinal degeneration and vision loss, cognitive and motor decline, ...seizures, and pronounced brain atrophy. This fatal pediatric disease is caused by mutations in the CLN2 gene which encodes the lysosomal enzyme tripeptidyl peptidase-1 (TPP1). Utilizing a TPP1−/− Dachshund model of CLN2 disease, studies were conducted to assess the effects of TPP1 enzyme replacement administered directly to the CNS on disease progression. Recombinant human TPP1 (rhTPP1) or artificial cerebrospinal fluid vehicle was administered to CLN2-affected dogs via infusion into the CSF. Untreated and vehicle treated affected dogs exhibited progressive declines in pupillary light reflexes (PLRs) and electroretinographic (ERG) responses to light stimuli. Studies were undertaken to determine whether CSF administration of rhTPP1 alters progression of the PLR and ERG deficits in the canine model. rhTPP1 administration did not inhibit the decline in ERG responses, as rhTPP1 treated, vehicle treated, and untreated dogs all exhibited similar progressive and profound declines in ERG amplitudes. However, in some of the dogs treated with rhTPP1 there were substantial delays in the appearance and progression of PLR deficits compared with untreated or vehicle treated affected dogs. These findings indicate that CSF administration of TPP1 can attenuate functional impairment of neural pathways involved in mediating the PLR but does not prevent loss of retinal responses detectable with ERG.
•Enzyme replacement therapy (ERT) to the CSF was evaluated for treating NCL in dogs.•ERT preserved the pupillary light reflex but not the electroretinogram.•ERT to the CSF will need to be supplemented with treatments targeted to the eye.
Purpose
The aim of this study was to examine coagulatory and fibrinolytic responses to the Western States Endurance Run (WSER, June 23 to 24, 2012). The WSER is a 161-km (100 mile) trail foot race ...through the Sierra Nevada Mountains that involves 6,030 m of climb and 7,001 m of descent.
Methods
We examined 12 men and 4 women mean (95 % CI), age 44.6 years (38.7–50.6) who completed the race (24.64 h; range 16.89–29.46). Blood samples were collected the morning before the race, immediately post-race, and 1 (D1) and 2 (D2) days post-race (corresponding to 51–54 h and 75–78 h from the start of the race, respectively). Hypercoagulable state was characterized by prothrombin fragment 1+2 (PTF 1+2) and thrombin–antithrombin complex (TAT). Fibrinolytic state was assessed by plasminogen activator inhibitor antigen (PAI-1 Ag), tissue plasminogen activator antigen (tPA Ag), and
d
-Dimer. Muscle damage was assessed by serum creatine kinase (CK) and myoglobin concentrations.
Results
Significant (
P
≤ 0.05) increases were observed immediately post-race for thrombin generation markers, PTF 1+2 (3.9-fold) and TAT (2.4-fold); markers of fibrinolysis, tPA Ag (4.0-fold), PAI-1 Ag (4.5-fold), and
d
-Dimer (2.2-fold); and muscle damage markers, CK (154-fold) and myoglobin (114-fold). Most markers continued to be elevated at D1, as seen by PTF 1+2, TAT (1.5- and 1.3-fold increase at D1), and
d
-Dimer (2.5- and 2.1-fold increase at D1 and D2, respectively). Additionally, PTF 1+2:tPA and TAT:tPA ratios, which assessed balance between coagulation and fibrinolysis, were slightly, but significantly increased at D1 (69 and 36 %) and D2 (19 and 31 %). CK and myoglobin also remained elevated at D1 (54- and 7-fold) and D2 (25- and 2-fold) time points.
Conclusion
The WSER produced extensive muscle damage and activated the coagulation and fibrinolytic systems. Since we observed a slight imbalance response between the two systems, a limited potential for thrombotic episodes is apparent in these highly trained athletes.
Abstract only
The Western States Endurance Run is a 100‐mile trail footrace through the Sierra Nevada Mountains. We hypothesized that the event would generate enough reactive oxygen species (ROS) in ...runners to cause ‘membrane damage’ as evidenced by degradation of highly unsaturated fatty acids, primarily arachidonate (AA) and docosahexaenoate (DHA). Ten runners (7M/3F, aged 27 to 60 yr) with a completion time of 22.83±4.26 hours provided buccal (cheek) cell and serum phospholipid (PL) samples for determination of fatty acid composition at baseline, immediately post‐race, and days 1 and 2 post‐race. Consistent with our hypothesis, cheek cell AA decreased by 19% (P = 0.003) and DHA by 23% (P = 0.002) immediately post‐race. In contrast, serum PL AA increased by 15% (P = 0.005) and DHA increased by 8% (NS). The implications of a decrease in cheek cell AA and DHA remain unclear, but they could reflect a failure of cellular antioxidant defenses to manage the cumulative ROS burden associated with ultra‐endurance exercise. The increase in serum PL AA may reflect release from other pools such as adipose tissue or damaged skeletal muscle, or alternatively it could represent an attempt to deliver AA to aid in repair and regeneration of ROS‐mediated tissue damage. The speed of fatty acid changes suggest that cheek cells can be used to assess acute systemic oxidative stress.
Abstract only
The aim of this study was to examine coagulation and fibrinolytic responses in runners competing in the Western States Endurance Run (WSER, June 23 to 24, 2012). The WSER is a 160‐km ...trail foot race through the Sierra Nevada Mountains that involves 15,540 ft of climb and 22,970 ft of descent. We examined 12 men and 4 women (mean±SE, age 44.6±3.0 y), who completed the race (24.64±1.07 hrs). Blood samples were collected the morning before the race, immediately post‐race, and 1 (D1) and 2 (D2) days post‐race (corresponding to 51 – 54 hr, and 75 – 78 hr from the start of the race, respectively). Muscle damage was assessed by serum creatine kinase (CK) and myoglobin. Hypercoagulable state was characterized by prothrombin fragment 1+2 (PTF 1+2) and thrombin‐antithrombin complex. Fibrinolytic state was assessed by plasminogen activator inhibitor antigen (PAI‐1 Ag), tissue plasminogen activator antigen (tPA Ag), and D‐Dimer. Significant increases were measured immediate post‐race for thrombin generation markers, PTF 1+2 and TAT; markers of fibrinolysis, tPA Ag, PAI‐1 Ag, and D‐Dimer; muscle damage markers, CK and myoglobin. Most markers returned to baseline levels at D1, except for PTF 1+2 and D‐Dimer. Muscle damage markers, CK and myoglobin; also continued to be elevated at D1 and D2 time points. In spite of these increases, no clinical evidence of vascular occlusion was observed following the race. In conclusion, the WSER produced extensive muscle damage and activated both the coagulation and fibrinolytic systems. Moreover, these systems are in balance thus limiting the potential of a thrombotic episode.
PDF
