Blood taken immediately after fatal resuscitation attempts yields higher quality DNA for genetic studies as compared to autopsy samples.

BACKGROUND: The out-of-hospital cardiac arrest (OHCA) in the young may be associated with a genetic predisposition which is relevant even for genetic counseling of relatives. The identification of genetic variants depends on the availability of intact genomic DNA. DNA from autopsy may be not available due to low autopsy frequencies or not suitable for high-throughput DNA sequencing (NGS). The emergency medical service (EMS) plays an important role to save biomaterial for subsequent molecular autopsy. It is not known whether the DNA integrity of samples collected by the EMS is better suited for NGS than autopsy specimens. MATERIAL AND METHODS: DNA integrity was analyzed by standardized protocols. Fourteen blood samples collected by the EMS and biomaterials from autopsy were compared. We collected 172 autopsy samples from different tissues and blood with postmortem intervals of 14-168 h. For comparison, DNA integrity derived from blood stored under experimental conditions was checked against autopsy blood after different time intervals. RESULTS: DNA integrity and extraction yield were higher in EMS blood compared to any autopsy tissue. DNA stability in autopsy specimens was highly variable and had unpredictable quality. In contrast, collecting blood samples by the EMS is feasible and delivered comparably the highest DNA integrity. CONCLUSIONS: Isolation yield and DNA integrity from blood samples collected by the EMS is superior in comparison to autopsy specimens. DNA from blood samples collected by the EMS on scene is stable at room temperature or even for days at 4 °C. We conclude that the EMS personnel should always save a blood sample of young fatal OHCA cases died on scene to enable subsequent genetic analysis.

The emergency medical service has a crucial role to unravel the genetics of sudden cardiac arrest in young, out of hospital resuscitated patients: Interim data from the MAP-IT study.

BACKGROUND: Genetics of sudden cardiac deaths (SCD) remains frequently undetected. Genetic analysis is recommended in undefined selected cases in the 2021 ERC-guideline. The emergency medical service and physicians (EMS) may play a pivotal role for unraveling SCD by saving biomaterial for later molecular autopsy. Since for high-throughput DNA-sequencing (NGS) high quality genomic DNA is needed. We investigated in a prospective proof-of-concept study the role of the EMS for the identification of genetic forms of SCDs in the young. METHODS: We included patients aged 1-50 years with need for cardiopulmonary resuscitation attempts (CPR). Cases with non-natural deaths were excluded. In two German counties with 562,904 residents 39,506 services were analysed. Paired end panel-sequencing was performed, and variants were classified according to guidelines of the American College of Medical Genetics (ACMG). RESULTS: 769 CPR-attempts were recorded (1.95% of all EMS-services; CPR-incidence 68/100,000). In 103 cases CPR were performed in patients < 50y. 58% died on scene, 26% were discharged from hospital. 24 subjects were included for genotyping. Of these 33% died on scene, 37.5% were discharged from hospital. 25% of the genotyped patients were carriers of (likely) pathogenic (ACMG-4/-5) variants. 67% carried variants with unknown significance (ACMG-3). 2 of them had familial history for arrhythmogenic cardiomyopathy or had to be re-classified as ACMG-4 carriers due to whole exome sequencing. CONCLUSION: The EMS contributes especially in fatal OHCA-cases to increase the yield of identified genetic conditions by collecting a blood sample on scene. Thus, the EMS can contribute significantly to primary and secondary prophylaxis in affected families.

Molecular autopsy and family screening in a young case of sudden cardiac death reveals an unusually severe case of FHL1 related hypertrophic cardiomyopathy.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is a genetic cardiomyopathy with a prevalence of about 1:200. It is characterized by left ventricular hypertrophy, diastolic dysfunction and interstitial fibrosis; HCM might lead to sudden cardiac death (SCD) especially in the young. Due to low autopsy frequencies of sudden unexplained deaths (SUD) the true prevalence of SCD and especially of HCM among SUD remains unclear. Even in cases of proven SCD genetic testing is not a routine procedure precluding appropriate risk stratification and counseling of relatives. METHODS: Here we report a case of SCD in a 19-year-old investigated by combined forensic and molecular autopsy. RESULTS: During autopsy of the index-patient HCM was detected. As no other possible cause of death could be uncovered by forensic autopsy the event was classified as SCD. Molecular autopsy identified two (probably) pathogenic genetic variants in FHL1 and MYBPC3. The MYBPC3 variant had an incomplete penetrance. The FHL1 variant was a de novo mutation. We detected reduced FHL1 mRNA levels and no FHL1 protein in muscle samples suggesting nonsense-mediated mRNA decay and/or degradation of the truncated protein in the SCD victim revealing a plausible disease mechanism. CONCLUSION: The identification of the genetic cause of the SCD contributed to the rational counseling of the relatives and risk assessment within the family. Furthermore our study revealed evidences for the pathomechanism of FHL1 mutations.

Incidence of pain after intravenous injection of a medium-/long-chain triglyceride emulsion of propofol. An observational study in 1375 patients.

BACKGROUND AND OBJECTIVE: To assess incidence and intensity of pain on intravenous injection of propofol (CAS 2078-548) in an emulsion of medium-chain/long-chain triglycerides (MCT/LCT, 50:50) in patients undergoing different elective surgical interventions. METHODS: The new solvent was used for induction of general anesthesia. Spontaneous pain reactions and pain elicited upon questioning were assessed. Patients were asked to grade the pain as mild, moderate or severe. Co-medication with sedative or analgesic drugs, size of the intravenous cannulae, site of injection and administration as a single bolus or in divided doses were recorded. RESULTS: Overall incidence of pain was 28.4% (390 out of 1375 patients). Twelve percent of the patients complained spontaneously and 16.4% reported pain after questioning. Pain intensity was graded as mild by 16.7% of the patients. The incidence of pain was significantly less when using an antecubital vein compared with a forearm or dorsal hand vein (p = 0.017 spontaneously reported pain, p = 0.001 pain elicited upon questioning). The number of patients complaining spontaneously of pain was significantly lower (p = 0.006) for large size than for small and medium size cannulae. CONCLUSIONS: The incidence of pain on injection of a medium-/long-chain triglyceride propofol formulation was 28.4% with 16.7% of the patients reporting mild pain. The use of an antecubital vein or a large size venous cannula appears to reduce the injection pain.

Linkage disequilibrium between tumor necrosis factor (TNF)-alpha-308 G/A promoter and TNF-beta NcoI polymorphisms: Association with TNF-alpha response of granulocytes to endotoxin stimulation.

OBJECTIVE: Controversial data have been reported on the association between the tumor necrosis factor (TNF)-alpha-308 G[U279C]A promoter polymorphism or the TNF-alpha I polymorphism with TNF-alpha plasma concentrations. The purpose of this study was to evaluate whether there is a linkage disequilibrium between the two polymorphisms. Moreover, the influence of these polymorphisms on the TNF-alpha synthesis of activated granulocytes was studied. DESIGN: Analysis of TNF-alpha concentrations of human whole blood after endotoxin stimulation. SETTING: Medical research laboratory. PATIENTS: Healthy human volunteers. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Healthy human volunteers were genotyped for both TNF polymorphisms by means of polymerase chain reaction. TNF-alpha plasma concentrations were determined with chemiluminescence after incubation of whole blood with endotoxin. A strong (p <.0001) linkage disequilibrium was found for the TNF-beta I and the TNF-alpha-308 genetic polymorphisms. Almost all individuals homozygous for the TNF-B2 allele of the TNF-beta I polymorphism were also TNF-alpha-308 G homozygotes. Carriers of the TNF-alpha-308 genotype AG had a significantly higher TNF-alpha production capacity than G homozygotes. The TNF-beta I genotype TNF-B1/TNF-B2 was associated with significantly higher TNF-alpha concentrations than the genotype TNF-B2/TNF-B2. Individuals homozygous for the TNF-B2 and the TNF-alpha-308 G alleles had a significantly reduced TNF-alpha response compared with individuals heterozygous for both TNF polymorphisms. CONCLUSIONS: A linkage disequilibrium between the two TNF polymorphisms was found. This study revealed a significant association between genotype and phenotype for both TNF polymorphisms. Heterozygosity for both TNF polymorphisms is associated with an increased TNF-alpha response.

The CD14-260 C --> T promoter polymorphism co-segregates with the tumor necrosis factor-alpha (TNF-alpha)-308 G --> A polymorphism and is associated with the interleukin-1 beta (IL-1 beta) synthesis capacity of human leukocytes.

Genetic variations contribute to the interindividual variance in the cytokine response to endotoxin. The gene of tumor necrosis factor-alpha (TNF-alpha) carries a polymorphism at position -308 of the promoter, consisting of a G/A exchange. To further elucidate the inherited mechanisms influencing cytokine levels, healthy human blood donors were studied. Genotyping for the TNF-alpha -308 and the CD14 -260 C/T promoter polymorphisms was carried out by real-time polymerase chain reaction assay using specific fluorescence-labelled hybridisation probes. A human whole blood assay was used to study the leukocyte TNF-alpha and IL-1 beta synthesis capacity upon endotoxin stimulation. We found a linkage disequilibrium between the TNF-alpha -308 G/A and the CD14 -260 C/T polymorphisms (p = 0.043). The CD14 -260 polymorphism was associated with IL-1 beta levels (p = 0.033) and higher values were found in C homozygotes. No association was found between the CD14 -260 genotypes or the TNF-alpha -308 - CD14 -260 genotypes and the TNF-alpha response.