Genetic Identification of Homozygous Familial Hypercholesterolemia by Long-Read Sequencing Among Patients With Clinically Diagnosed Heterozygous Familial Hypercholesterolemia

BACKGROUND

Homozygous familial hypercholesterolemia (HoFH) is a rare genetic disorder characterized by extremely elevated plasma LDL-C (low-density lipoprotein cholesterol) and accelerated atherosclerosis. Accurate identification of patients with HoFH is essential as they may be eligible for specialized treatments. We hypothesized that a subset of patients with clinically diagnosed heterozygous FH (HeFH) may in fact have HoFH, and this could be identified by genetic diagnosis.

METHODS

We recruited patients with a clinical diagnosis of HeFH based on a Dutch Lipid Clinic Network score ≥6 and no secondary cause of hypercholesterolemia. We performed targeted next-generation sequencing of the LDLR, APOB, PCSK9, and LDLRAP1 genes, followed by long-read sequencing of the LDLR gene in patients with >1 pathogenic LDLR variant. We examined lipid levels and cardiovascular events.

RESULTS

Among 705 patients with clinically diagnosed HeFH, we identified a single pathogenic variant in 300 (42.6%) and >1 pathogenic variant in the LDLR gene in 11 patients (1.6%). We established a genetic diagnosis of HoFH in 6 (0.9%) patients (3 true homozygotes and 3 compound heterozygotes). The mean baseline LDL-C and prevalence of premature cardiovascular disease of patients with genetically identified HoFH was significantly higher than patients with HeFH.

CONCLUSIONS

In a cohort of patients with clinically diagnosed HeFH, genetic testing including long-read sequencing revealed that 0.9% had HoFH. These patients tended to have a more severe clinical phenotype. Genetic testing of patients with clinical FH may identify patients with HoFH that had eluded clinical diagnosis.

Exercise, Processing Speed, and Subsequent Falls: A Secondary Analysis of a 12-Month Randomized Controlled Trial

BACKGROUND

Strength and balance retraining exercises reduce the rate of subsequent falls in community-dwelling older adults who have previously fallen. Exercise can also improve cognitive function, including processing speed. Given processing speed predicts subsequent falls, we aimed to determine whether improved processing speed mediated the effects of the Otago Exercise Program on the rate of subsequent: (i) total falls, (ii) non-injurious falls, (iii) moderate injurious falls, and (iv) serious injurious falls.

METHOD

A secondary complete case analysis of a 12-month, single-blind, randomized clinical trial among 256 of 344 adults aged at least 70 years who fell in the previous 12 months. Participants were randomized 1:1 to receive usual care plus the Otago Exercise Program (n = 123) or usual care (n = 133), consisting of fall prevention care provided by a geriatrician. The primary outcome was self-reported number of falls over 12 months (ie, rate of falls). Processing speed was assessed at baseline and at 12 months by the Digit Symbol Substitution Test (DSST). Causal mediation analyses were conducted using quasi-Bayesian estimates and 95% confidence intervals.

RESULTS

Exercise significantly reduced the rate of subsequent moderate injurious falls (IRR = 0.49; 95% CI: 0.31, 0.77; p = .002) and improved processing speed (estimated mean difference: 1.16 points; 95% CI: 0.11, 2.21). Improved DSST mediated the effect of exercise on the rate of subsequent moderate injurious falls (estimate: -0.06; 95% CI: -0.15, -0.001; p = .036).

CONCLUSION

Improved processing speed may be a mechanism by which exercise reduces subsequent moderate injurious falls in older adults who fell previously.

CLINICAL TRIALS REGISTRATION NUMBER

ClinicalTrials.gov Protocol Registration System:NCT01029171: https://clinicaltrials.gov/ct2/show/NCT01029171NCT00323596: https://clinicaltrials.gov/ct2/show/NCT00323596.

Sex Differences in Subsequent Falls and Falls Risk: A Prospective Cohort Study in Older Adults

BACKGROUND

Sex differences for subsequent falls and falls risk factors in community-dwelling older adults who have fallen are unknown. Our aim was to: (1) compare the number of falls between sexes, (2) identify modifiable falls risk factors, and (3) explore the interaction of sex on falls risk factors in older adults who fall.

METHODS

Four hundred sixty-two community dwellers seeking medical attention after an index fall were recruited from the Vancouver Falls Prevention Clinic and participated in this 12-month prospective cohort study. Ninety-six participants were part of a randomized controlled trial of exercise. Falls were tracked with monthly falls calendars. Demographics, falls risk measures, and the number of subsequent falls were compared between sexes. A principal component analysis (PCA) was employed to reduce the falls risk measures to a smaller set of factors. The PCA factors were used in negative binomial regression models to predict the number of subsequent falls. Age, exposure time (i.e., number of falls monitoring days), and prescribed exercise (yes/no) were used as covariates, and sex (male/female) and PCA factors were used as main effects. The interaction of sex by PCA factor was then included.

RESULTS

Males fell more over 12 months (males: 2.80 ± 6.86 falls; females: 1.25 ± 2.63 falls) than females, and poorer executive function predicted falls in males. Four PCA factors were defined - impaired cognition and mobility, low mood and self-efficacy, mobility resilience, and perceived poor health - each predicted the number of falls. The sex by mobility resilience interaction suggested that mobility resilience was less protective of falls in males.

CONCLUSION

Modifiable risk factors related to cognition, physical function, psychological wellbeing, and health status predicted subsequent falls. In males, better mobility was not as protective of falls compared with females. This may be due to males' poorer executive function, contributing to decreased judgement or slowed decision-making during mobility. These results may inform efficacious sex-specific falls prevention strategies.

Event-related changes of the prefrontal cortex oxygen delivery and metabolism during driving measured by hyperspectral fNIRS

Recent technological advancements in optical spectroscopy allow for the construction of hyperspectral (broadband) portable tissue oximeters. In a series of our recent papers we have shown that hyperspectral NIRS (hNIRS) has similar or better capabilities in the absolute tissue oximetry as frequency-domain NIRS, and that hNIRS is also very efficient in measuring temporal changes in tissue hemoglobin concentration and oxygenation. In this paper, we extend the application of hNIRS to the measurement of event-related hemodynamic and metabolic functional cerebral responses during simulated driving. In order to check if hNIRS can detect event-related changes in the brain, we measured the concentration changes of oxygenated (HbO2) and deoxygenated (HHb) hemoglobin and of the oxidized state of cytochrome c oxidase, on the right and left prefrontal cortices (PFC) simultaneously during simulated driving on sixteen healthy right-handed participants (aged between 22-32). We used our in-house hNIRS system based on a portable spectrometer with cooled CCD detector and a driving simulator with a fully functional steering wheel and foot pedals. Each participant performed different driving tasks and participants were distracted during some driving conditions by asking general knowledge true/false questions. Our findings suggest that more complex driving tasks (non-distracted) deactivate PFC while distractions during driving significantly activate PFC, which is in agreement with previous fMRI results. Also, we found the changes in the redox state of the cytochrome C oxidase to be very consistent with those in the concentrations of HbO2 and HHb. Overall our findings suggest that in addition to the suitability of absolute tissue oximetry, hyperspectral NIRS may also offer advantages in functional brain imaging. In particular, it can be used to measure the metabolic functional brain activity during actual driving.

Abstract WP150: The Effects of Chronic Stroke on Brain Function While Driving

Introduction: Chronic stroke may lead to persistent cognitive deficits in multiple domains. Despite this issue, there are no clear guidelines about post-stroke fitness to drive, due to a limited understanding of how stroke impairs brain networks essential for driving. We hypothesize reduced activity in driving-related brain regions, for more cognitively demanding tasks (e.g. left turns with traffic, distraction) and individuals with poorer neurocognitive test scores.

Methods: we tested 7 adults with prior ischemic stroke (44-71 yrs.) and imaged brain function using functional Magnetic Resonance Imaging (fMRI) while they performed simulated driving scenarios, using our novel MRI-compatible simulator system. Performance was compared to 10 healthy age-matched controls (56-75 yrs.).

Results: chronic stroke patients showed similar posterior brain activations as controls (e.g. visual and prefrontal lobes, precuneus). However, individuals with lower neurocognitive test scores (e.g. Montreal Cognitive Assessment, Trail-Making Test) had greater posterior activation during turning tasks, potentially due to increased cognitive effort. They also showed greater reductions in activity during distraction tasks, indicating brain function is more sensitive to distracting stimuli. Functional abnormalities were not proximal to infarcts, indicating non-focal alterations of brain networks following stroke.

Conclusions: This is the first demonstration of systematic changes in brain function for stroke patients, and relation to clinical measures. This may have implications in our understanding of how stroke affects brain function during integrative, real-world tasks.

Evaluation of three purely polypropylene meshes of different pore sizes in an onlay position in a New Zealand white rabbit model

BACKGROUND

The aim of the study was to evaluate the influence of the pore size of a polypropylene mesh on the shrinkage and elasticity of the mesh-tissue complex and the inflammatory reaction to the implant in an open onlay hernia repair.

MATERIALS AND METHODS

Twenty-one 10 × 10 cm samples of polypropylene meshes of a different pore size (3.0 × 2.8 mm-PP3, 1.0 × 0.8 mm-PP1 and 0.6 × 0.5 mm-PP.5) were implanted in an onlay position in 21 New Zealand white rabbits. After 90 days of implantation the shrinkage, elasticity and foreign body reaction (FBR) were assessed.

RESULTS

The shrinkage of PP3 was 30.6 ± 4.3 %, PP1 49.3 ± 2.9 % and PP.5 49.5 ± 2.6 %. The shrinkage of PP3 was significantly lower (PP3 × PP1 p = 0.007, PP3 × PP.5 p = 0.005), PP1 and PP.5 were similar. The elasticity was similar. The strength of FBR in mesh pores was similar. The width of foreign body granuloma layers at the mesh-tissue interface was significantly reduced with increasing pore size (inner: PP3 10.1 ± 1.2; PP1 12.5 ± 2.9; PP.5 17.4 ± 5.2 and outer: PP3 21.2 ± 2.5; PP1 30.6 ± 6.3; PP.5 60.4 ± 14.9). All differences between the widths of granuloma layers were statistically significant (p < 0.010). One animal (PP1) was excluded because of a mesh infection.

CONCLUSIONS

Implantation of polypropylene mesh of a pore size of 3 mm in an onlay position is associated with a significant reduction of shrinkage in comparison to a 1 mm pore lightweight and 0.5 mm pore heavyweight mesh. A pore size increase to 3 mm is not sufficient for an improvement of mesh-tissue complex elasticity in comparison to a 1 mm pore lightweight and 0.5 mm heavyweight mesh. Polypropylene mesh with enlarged pores to 3 mm is associated with a similar strength of FBR in mesh pores and a reduced foreign body granuloma in comparison to a 1 mm pore lightweight and 0.5 mm pore heavyweight mesh.

[Analysis of prognostic factors in osteosarcoma adult patients, a single institution experience]

BACKGROUND

The objective of this report was to estimate long-term outcome and prognostic factors in adult patients with high-grade osteosarcoma. The intended therapeutic strategy included preoperative and/or postoperative chemotherapy as well as surgery of all operable lesions.

PATIENTS AND METHODS

We reviewed the clinical data of 36 newly diagnosed adult patients (aged 19-82, average 37.5, median 28.5 years) with high-grade osteosarcoma of the trunk or limbs evaluated by a multidisciplinary team and treated between 1999 and 2010 in Brno. Forty-five percent of patients were over thirty, more than 36% over forty. Thirty-one percent of patients had metastasis at the time of diagnosis. Demographic parameters, tumor-related and treatment-related variables included possible prognostic factors and their impact on response, overall survival (OS) and event-free survival (EFS) were analyzed.

RESULTS

All the patients were followed up after treatment. Seventy-three percent of patients were poor responders to chemotherapy. Sixteen patients are alive, and twenty patients died. The survival time ranged from 2 to 177 months (average 45 months, median survival 23 months). The 5-year OS of all patients was 52.4%. OS of patients without metastasis was 68.12%, while 2-year OS with metastasis was 26% only. 5-year EFS was 38.7%. Univariate analysis revealed that the prognosis of adult osteosarcoma patients was significantly related to distant metastasis (p = 0.006), surgical stage (p = 0.00582), serum alkaline phosphatase (ALP) level (p = 0.00841) and serum lactatdehydrogenase (LD) level (p = 0.047). The other analyzed prognostic factors including age had no statistically significant influence on outcome of osteosarcoma in adult patients.

CONCLUSION

The prognosis of osteosarcoma in adult patients was significantly correlated to surgical stage, distant metastasis, serum ALP and LD.