Post-Concussion Acute Signs and Reliable Cognitive Decline in a Finnish Youth Ice Hockey Sample

M1 - acaa108In sports concussion research, the importance of an individualized approach incorporating neuropsychological assessment data has been emphasized. This study examined the impact of acute signs of concussion on post-injury cognitive functioning using reliable change methodology in a sample of Finnish, elite-level, youth ice hockey players.From a sample of 1,823 players (all male, 14–20 years old) who completed preseason baseline testing with the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT®) battery, two subgroups were identified. First, in total, 312 uninjured athletes, who completed baseline testing twice—1 year apart. The scores were contrasted to calculate reliable change indices (RCIs). Second, from a subsample of 570 athletes participating in an intensive follow-up arm of the project, the analysis included 32 concussed athletes. The RCIs were determined for the five ImPACT composite scores and used in identifying athletes with declined performance 3 days post-injury.Test-retest reliability ranged from .39 to .71. Athletes who had experienced an acute loss of consciousness, amnesia, or postural instability had increased odds for declines in two or more areas assessed by ImPACT (odds ratio = 7.67–8.00, p < .05). In contrast, acute disorientation or vacant look did not lead to cognitive change that met the reliable change threshold.The reliability coefficients and RCIs differed from those published earlier emphasizing the importance of national reference values. The presence of acute loss of consciousness, amnesia, or postural instability may indicate a more severe injury and predict the need for more intensive cognitive follow-up.Objective In sports concussion research, the importance of an individualized approach incorporating neuropsychological assessment data has been emphasized. This study examined the impact of acute signs of concussion on post-injury cognitive functioning using reliable change methodology in a sample of Finnish, elite-level, youth ice hockey players. Methods From a sample of 1,823 players (all male, 14-20 years old) who completed preseason baseline testing with the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT (R)) battery, two subgroups were identified. First, in total, 312 uninjured athletes, who completed baseline testing twice-1 year apart. The scores were contrasted to calculate reliable change indices (RCIs). Second, from a subsample of 570 athletes participating in an intensive follow-up arm of the project, the analysis included 32 concussed athletes. The RCIs were determined for the five ImPACT composite scores and used in identifying athletes with declined performance 3 days post-injury. Results Test-retest reliability ranged from .39 to .71. Athletes who had experienced an acute loss of consciousness, amnesia, or postural instability had increased odds for declines in two or more areas assessed by ImPACT (odds ratio = 7.67-8.00, p < .05). In contrast, acute disorientation or vacant look did not lead to cognitive change that met the reliable change threshold. Conclusions The reliability coefficients and RCIs differed from those published earlier emphasizing the importance of national reference values. The presence of acute loss of consciousness, amnesia, or postural instability may indicate a more severe injury and predict the need for more intensive cognitive follow-up.Peer reviewe

Adolescent athletes with learning disability display atypical maturational trajectories on concussion baseline testing : Implications based on a Finnish sample

Previous research has reported lower cognitive test scores on baseline testing in athletes reporting multiple previous concussions or a history of learning disability (LD). Age also has an important influence on cognitive performance. While these factors have been considered individually in previous studies, the present study is the first to explore the interaction of age, self-reported LD, and history of concussion on baseline Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT (R)) in a nationwide study of adolescent athletes. ImPACT (R) was administered to 1823 Finnish male ice hockey players (aged 12-21 years old) prior to the 2015-2016 or 2016-2017 playing seasons. Linear regressions and simple slopes analyses were used for clarifying the impact of LD and previous concussion history on maturational trajectories. In comparison to typically developing athletes, athletes with LD had lower neurocognitive scores in all composites and differing maturational trajectory in verbal memory and visual motor speed. The number of previous concussions did not impair neurocognitive performance at baseline assessment. Application of standard age-based norms to adolescent athletes with a history of LD has the potential to negatively skew clinical decision-making. Separate reference values for LD athletes are warranted due to their unique developmental cognitive trajectories. The reference values for the Finnish participants in this study are presented.Peer reviewe

Impaired osteoclast homeostasis in the cystatin B-deficient mouse model of progressive myoclonus epilepsy

Peer reviewe

Unsatisfactory gene transfer into bone-resorbing osteoclasts with liposomal transfection systems

BACKGROUND: Bone-resorbing osteoclasts are multinucleated cells that are formed via fusion of their hematopoietic stem cells. Many of the details of osteoclast formation, activation and motility remain unsolved. Therefore, there is an interest among bone biologists to transfect the terminally differentiated osteoclasts and follow their responses to the transgenes in vitro. Severe difficulties in transfecting the large, adherent osteoclasts have been encountered, however, making the use of modern cell biology tools in osteoclast research challenging. Transfection of mature osteoclasts by non-viral gene transfer systems has not been reported. RESULTS: We have systematically screened the usefulness of several commercial DNA transfection systems in human osteoclasts and their mononuclear precursor cell cultures, and compared transfection efficacy to adenoviral DNA transfection. None of the liposome-based or endosome disruption-inducing systems could induce EGFP-actin expression in terminally differentiated osteoclasts. Instead, a massive cell death by apoptosis was found with all concentrations and liposome/DNA-ratios tested. Best transfection efficiencies were obtained by adenoviral gene delivery. Marginal DNA transfection was obtained by just adding the DNA to the cell culture medium. When bone marrow-derived CD34-positive precursor cells were transfected, some GFP-expression was found at the latest 24 h after transfection. Large numbers of apoptotic cells were found and those cells that remained alive, failed to form osteoclasts when cultured in the presence of RANKL and M-CSF, key regulators of osteoclast formation. In comparison, adenoviral gene delivery resulted in the transfection of CD34-positive cells that remained GFP-positive for up to 5 days and allowed osteoclast formation. CONCLUSION: Osteoclasts and their precursors are sensitive to liposomal transfection systems, which induce osteoclast apoptosis. Gene transfer to mononuclear osteoclast precursors or differentiated osteoclasts was not possible with any of the commercial transfection systems tested. Osteoclasts are non-dividing, adherent cells that are difficult to grow as confluent cultures, which may explain problems with transfection reagents. Large numbers of α(v)β(3 )integrin on the osteoclast surface allows adenovirus endocytosis and infection proceeds in dividing and non-dividing cells efficiently. Viral gene delivery is therefore currently the method of choice for osteoclast transfection

On-field signs of concussion predict deficits in cognitive functioning: Loss of consciousness, amnesia, and vacant look

The usefulness of on-field signs in predicting concussion outcome is under debate. We studied the prevalence of these signs and analyzed the predictive value for post-injury cognitive recovery in Finnish elite-level youth ice hockey players. Of the 570 consecutive athletes, 52 were concussed during seasons 2015-2017. After exclusion criterion analysis included 34 hockey players (14-20 years-old). Follow-up assessment was performed seven days post-injury and compared with pre-injury baseline. Cognitive performance was assessed using the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT (R)) battery. Hierarchical regression analyses were conducted to examine the relationship between on-field signs of concussion and the post-injury change in cognitive performance. The findings indicated that on-field loss of consciousness, amnesia, and vacant look were associated with larger decrements in cognition. Loss of consciousness accounted for 22% of the variance in verbal memory scores; amnesia accounted for 15% of the variance in verbal memory scores, and the presence of vacant look accounted for 9% of the variance in visual memory performance. The presence of loss of consciousness, amnesia, or vacant look is risk factors for longer recovery times and predict the need for extended cognitive follow-up

Noninvasive and Quantitative Monitoring of the Distributions and Kinetics of MicroRNA-Targeting Molecules in Vivo by Positron Emission Tomography

MicroRNAs (miRNAs) are endogenous, small, noncoding ribonucleic acids (RNAs) that bind to the 3' untranslated regions of messenger RNAs (mRNAs) and induce translational repression or mRNA degradation. Although numerous studies have reported that miRNAs are of potential use for disease diagnostics and gene therapy, little is known about their fates in vivo. This study elucidated the whole-body distributions and kinetics of intravenously administered miRNA-targeting molecules in vivo by positron emission tomography (PET) imaging. A 22-mer sequence targeting miR-1513 was conjugated with three different chelators and labeled with gallium-68 (Ga-68). These tracers were compared with a scrambled 22-mer sequence; 22-mer with two single base substitutions; anti-miR-34 22-mer; hexathymidylate (T-6), a 6-mer sequence; and an unconjugated chelator. miR-15b was chosen as a target because it is important for bone remodeling. All three Ga-68-labeled anti-miR-15b molecules had similar biodistributions and kinetics, and they all accumulated in the bones, kidneys, and liver. The bone accumulation of these tracers was the highest in the epiphyses of long tubular bones, maxilla, and mandible. By contrast, the scrambled 22-mer sequence, the 6-mer, and the unconjugated chelator did not accumulate in bones. PET imaging successfully elucidated the distributions and kinetics of Ga-68-labeled chelated miRNA-targeting molecules in vivo. This approach is potentially useful to evaluate new miRNA-based drugs

Signature of circulating small non-coding RNAs during early fracture healing in mice

Fracture healing is a complex process with multiple overlapping metabolic and differentiation phases. Small non-coding RNAs are involved in the regulation of fracture healing and their presence in circulation is under current interest due to their obvious value as potential biomarkers. Circulating microRNAs (miRNAs) have been characterized to some extent but the current knowledge on tRNA-derived small RNA fragments (tsRNAs) is relatively scarce, especially in circulation.In this study, the spectrum of circulating miRNAs and tsRNAs was analysed by next generation sequencing to show their differential expression during fracture healing in vivo. Analysed tsRNA fragments included stress-induced translation interfering tRNA fragments (tiRNAs or tRNA halves) and internal tRNA fragments (i-tRF), within the size range of 28–36 bp. To unveil the expression of these non-coding RNAs, genome-wide analysis was performed on two months old C57BL/6 mice on days 1, 5, 7, 10, and 14 (D1, D5, D7, D10, and D14) after a closed tibial fracture.Valine isoacceptor tRNA-derived Val-AAC 5′end and Val-CAC 5′end fragments were the major types of 5′end tiRNAs in circulation, comprising about 65 % of the total counts. Their expression was not affected by fracture. After a fracture, the levels of two 5′end tiRNAs Lys-TTT 5′ and Lys-CTT 5′ were decreased and His-GTG 5′ was increased through D1-D14. The level of miR-451a was decreased on the first post-fracture day (D1), whereas miR-328-3p, miR-133a-3p, miR-375-3p, miR-423-5p, and miR-150-5p were increased post-fracture. These data provide evidence on how fracture healing could provoke systemic metabolic effects and further pinpoint the potential of small non-coding RNAs as biomarkers for tissue regeneration.</p

Multiple targets identified with genome wide profiling of small RNA and mRNA expression are linked to fracture healing in mice

Long-bone fracture is a common injury and its healing process at the fracture site involves several overlapping phases, including inflammation, migration of mesenchymal progenitors into the fracture site, endochondral ossification, angiogenesis and finally bone remodelling. Increasing evidence shows that small noncoding RNAs are important regulators of chondrogenesis, osteogenesis and fracture healing. MicroRNAs are small single-stranded, non-coding RNA-molecules intervening in most physiological and biological processes, including fracture healing. Angiogenin-cleaved 5' tRNA halves, also called as tiRNAs (stress-induced RNAs) have been shown to repress protein translation. In order to gain further understanding on the role of small noncoding RNAs in fracture healing, genome wide expression profiles of tiRNAs, miRNAs and mRNAs were followed up to 14 days after fracture in callus tissue of an in vivo mouse model with closed tibial fracture and, compared to intact bone and articular cartilage at 2 months of age. Total tiRNA expression level in cartilage was only approximately one third of that observed in control D0 bone. In callus tissue, 11 mature 5'end tiRNAs out of 191 tiRNAs were highly expressed, and seven of them were differentially expressed during fracture healing. When comparing the control tissues, 25 miRNAs characteristic to bone and 29 miRNAs characteristic to cartilage tissue homeostasis were identified. Further, a total of 54 out of 806 miRNAs and 5420 out of 18,700 mRNAs were differentially expressed (DE) in callus tissue during fracture healing and, in comparison to control bone. They were associated to gene ontology processes related to mesenchymal tissue development and differentiation. A total of 581 miRNA-mRNA interactions were identified for these 54 DE miRNAs by literature searches in PubMed, thereby linking by Spearman correlation analysis 14 downregulated and 28 upregulated miRNAs to 164 negatively correlating and 168 positively correlating miRNA-mRNA pairs with chondrogenic and osteogenic phases of fracture healing. These data indicated that tiRNAs and miRNAs were differentially expressed in fracture callus tissue, suggesting them important physiological functions during fracture healing. Hence, the data provided by this study may contribute to future clinical applications, such as potential use as biomarkers or as tools in the development of novel therapeutic approaches for fracture healing.</p