Differences In Clinical Severity Research Articles

Functional metagenomics highlights varied infection states with dynamics of pathogens and antibiotic resistance in lower respiratory tract infections

BackgroundAntimicrobial resistance (AMR) amongst pathogenic bacterial species poses significant challenges in treating infections of the lower respiratory tract (LRT), leading to higher hospitalization and mortality rates. MethodsBronchoalveolar lavage fluid (BALF) from 84 clinically adjudicated LRTI patients were subjected to respiratory pathogen ID/AMR (RPIP) enrichment and sequencing followed by Explify and CZID seq data analysis to identify potential LRTI pathogens and associated AMR genes. Patients were categorized as LRTI-WP (with pneumonia) and LRTI-WoP (without pneumonia). FindingsmNGS achieved 100 % pathogen detection compared to 73 % through clinician-used BioFire panel. Predominant pathogens included Acinetobacter baumannii, Klebsiella pneumoniae along with detection of Aspergillus versicolor and Herpes simplex virus. Double and polymicrobial infections were captured, involving non-respiratory pathogens like Rothia mucilaginosa, Escherichia coli, and Moraxella osloensis. AMR detection highlighted macrolide (MPH; ERM) and Sulfonamide (SUL) rich resistome in 60 % of patients followed by extended spectrum beta lactamase (OXA) and tetracycline (TET). LRTI-WP showed high abundance of A. baumannii, majorly associated with MPH whereas K. pneumoniae with beta-lactams was comparable in both groups. Differences in clinical severity may stem from non-respiratory pathogens, newly recognized via mNGS. CZID seq pipeline validated and revealed additional microbes and AMR genes in the cohort. InterpretationThe prevalence of common pathogens like A. baumannii and K. pneumoniae along with the non-respiratory pathogens identified by RPIP-Explify and CZID seq provided an understanding to evaluate the LRTI. mNGS is crucial for precise pathogen and antibiotic resistance detection, vital for combating antibiotic resistance.

Trial Design with Win Statistics for Multiple Time-to-Event Endpoints with Hierarchy

The conventional approach to the analysis of composite endpoints is time-to-first event analysis. However, this approach has been criticized because it ignores the differences in clinical severity and may end up emphasizing the less severe time-to-event. To overcome this limitation, win statistics (win ratio, win odds, or net benefit) have become popular in analysis of hierarchical time to event endpoints. However, design of randomized clinical trials using the win statistics is lagging behind. In this article, we derive formulas for the win statistics and probability of ties under specific assumptions that can be useful in practice. We also address two design issues: the selection of meaningful and justifiable design parameters and power calculations, when the win statistics method is the primary analysis method for multiple time-to-event endpoints for a pre-specified hierarchy. Finally, we identify patterns where the win statistics approach would have greater statistical power than time-to-first event analysis. Several examples are used to illustrate the usefulness of the formula-based power calculations.

Differences Between RSVA and RSVB Subgroups and Implications for Pharmaceutical Preventive Measures.

Understanding the differences between respiratory syncytial virus (RSV) subgroupsA and B provides insights for the development of prevention strategies and public health interventions. We aimed to describe the structural differences of RSV subgroups, their epidemiology, and genomic diversity. The associated immune response and differences in clinical severity were also investigated. A literature review from PubMed and Google Scholar (1985-2023) was performed and extended using snowballing from references in captured publications. RSV has two major antigenic subgroups, A and B, defined by the Gglycoprotein. The RSVF fusion glycoprotein in the prefusion conformation is a major target of virus neutralizing antibodies and differs in surface exposed regions between RSVA and RSVB. The subgroups co-circulate annually, but there is considerable debate as to whether clinical severity is impacted by the subgroup of the infecting RSV strain. Large variations between the studies reporting RSV subgroup impact on clinical severity were observed. A tendency for higher disease severity may be attributed to RSVA but no consensus could be reached as to whether infection by one of the subgroup caused more severe outcomes. RSV genotype diversity decreased over the last two decades, and ON and BA have become the sole lineages detected for RSVA and RSVB, since 2014. No studies with data obtained after 2014 reported a difference in disease severity between the two subgroups. RSVF is relatively well conserved and highly similar between RSVA and B, but changes in the amino acid sequence have been observed. Some of these changes led to differences in F antigenic sites compared to reference F sequences (e.g., RSV/A Long strain), which are more pronounced in antigenic sites of the prefusion conformation of RSVB. Initial results from the second season after vaccination suggest specific RSVB efficacy wanes more rapidly than RSVA for RSV PreF-based monovalent vaccines. RSVA and RSVB both contribute substantially to the global RSV burden. Both RSV subgroups cause severe disease and none of the available evidence to date suggests any differences in clinical severity between the subgroups. Therefore, it is important to implement measures effective at preventing disease due to both RSVA and RSVB to ensure impactful public health interventions. Monitoring overtime will be needed to assess the impact of waning antibody levels on subgroup-specific efficacy.

Molecular and Clinical Features of Congenital Hypothyroidism Due to Multiple DUOX2 Variants.

Background: DUOX2 is one of the major causative genes of congenital hypothyroidism (CH). Still, the mutation spectrum and clinical outcomes of biallelic DUOX2 variants are not fully understood. This study aimed to elucidate the molecular features and long-term clinical manifestations of CH caused by multiple pathogenic DUOX2 variants. Methods: A total of 255 patients with CH were screened for rare variants of 11 known causative genes. DUOX2 variants were classified according to their protein structure and residual activity. In vitro assays were performed for several variants of unknown functions. Clinical analyses were conducted for patients with multiple pathogenic variants of DUOX2 but not of other genes. Results: We identified 24 pathogenic variants of DUOX2, together with two benign variants and seven variants of uncertain significance, in 63 patients. The pathogenic variants included three missense substitutions and one frameshift variant that have not yet been linked to CH. Twenty-one patients carried multiple pathogenic DUOX2 variants without any other pathogenic gene variants. Three of the 21 patients harbored homozygous variants. Family analysis, long-read amplicon sequencing, and haplotype phasing confirmed compound heterozygosity of the DUOX2 variants in 14 patients, whereas the allelic positions of the variants in the remaining four patients could not be determined. Of the 21 patients, 19 were treated with levothyroxine; their ages at drug withdrawal ranged from 9 months to 21.4 years. Three patients required retreatment after drug-free intervals of 6 months, 8 months, and 10 years. There were no differences in clinical severity among patients with DUOX2 amorphic/amorphic, amorphic/hypomorphic, and hypomorphic/hypomorphic variants. Conclusions: These results broaden the mutational spectrum of DUOX2. Furthermore, our data imply that patients with multiple pathogenic DUOX2 variants typically exhibit transient CH without significant genotype-phenotype correlations. Most importantly, this study demonstrated for the first time that these patients are at risk of developing recurrent hypothyroidism after a long drug-free interval.

Nirsevimab immunization's real-world effectiveness in preventing severe bronchiolitis: A test-negative case-control study.

Several clinical trials have shown that nirsevimab, an antibody targeting the respiratory syncytial virus (RSV), reduces RSV bronchiolitis requiring admission. In 2023-2024, Catalonia and Andorra adopted immunization strategies for children <6 months and those born during the epidemic season. This study evaluates the effectiveness of nirsevimab in preventing hospitalizations from RSV bronchiolitis. In the epidemic season of 2023-2024, a test-negative case-control study was conducted in three hospitals from Catalonia and Andorra. Patients <12 months old admitted with bronchiolitis and tested for RSV using molecular microbiology tests were included. The effectiveness in preventing RSV bronchiolitis hospitalization and severe disease was estimated using multivariate models. Comparisons between immunized, non-immunized, and non-eligible patients were made in prospectively collected epidemiological, clinical, and microbiological variables. Two hundred thirty-four patients were included. RSV was detected in 141/234 (60.2%), being less common in the immunized group (37% vs 75%, p < .001). The rate of immunized patients among those eligible was 59.7%. The estimated effectiveness for RSV-associated lower respiratory tract infection was 81.0% (95% confidence interval: 60.9-90.7), and for preventing severe disease (the need for NIV/CMV), 85.6% (41.7-96.4%). No significant differences by immunization status were observed in patients with RSV concerning viral coinfections, the need for NIV/CMV or length of hospital stay. This study provides real-world evidence of the effectiveness of nirsevimab in preventing RSV-lower respiratory tract infection hospitalization and severe disease in infants during their first RSV season following a systematic immunization program. Immunized patients did not exhibit a higher rate of viral coinfections nor differences in clinical severity once admitted.

Computed tomography in patients with sepsis presenting to the emergency department: exploring its role in light of patient outcomes

ObjectivesThis study aimed to explore the role of CT in septic patients presenting to the emergency department (ED).Materials and methodsWe performed a retrospective secondary analysis of 192 septic patients from a prospective observational study, i.e., the “LIFE POC” study. Sepsis was diagnosed in accordance with the Sepsis-3 definition. Clinical and radiological data were collected from the hospital administration and radiological systems. Information on mortality and morbidity was collected. Time-to-CT between CT scan and sepsis diagnosis (ttCTsd) was calculated. Diagnostic accuracy was assessed with the final sepsis source as reference standard. The reference standard was established through the treating team of the patient based on all available clinical, imaging, and microbiological data.ResultsSixty-two of 192 patients underwent a CT examination for sepsis focus detection. The final septic source was identified by CT in 69.4% (n = 43). CT detected septic foci with 81.1% sensitivity (95% CI, 68.0–90.6%) and 55.6% specificity (95% CI, 21.2–86.3%). Patients with short versus long ttCTsd did not differ in terms of mortality (16.1%, n = 5 vs 9.7, n = 3; p = 0.449), length of hospital stay (median 16 d, IQR 9 d 12 h–23 d 18 h vs median 13 d, IQR 10 d 00 h–24 d 00 h; p = 0.863), or duration of intensive care (median 3d 12 h, IQR 2 d 6 h–7 d 18 h vs median 5d, IQR 2 d–11 d; p = 0.800).ConclusionsOur findings show a high sensitivity of CT in ED patients with sepsis, confirming its relevance in guiding treatment decisions. The low specificity suggests that a negative CT requires further ancillary diagnostic tests for focus detection. The timing of CT did not affect morbidity or mortality outcomes.Clinical relevance statementIn patients with sepsis who present to the ED, CT can be used to identify infectious foci on the basis of clinical suspicion, but should not be used as a rule-out test. Scientific evidence for the optimal timing of CT beyond clinical decision-making is currently missing, as potential mortality benefits are clouded by differences in clinical severity at the time of ED presentation.Key Points• In patients with sepsis who present to the ED, CT for focus identification has a high sensitivity and can thereby be valuable for patient management.• As the specificity is considerably lower, a thorough microbiological assessment is important in these cases.• The timing of CT did not affect morbidity and mortality outcomes in this study, which might be due to variability in clinical severity at the time of ED presentation.

RSV Disease Burden in Primary Care in Italy: A Multi-Region Pediatric Study, Winter Season 2022-2023.

Human respiratory syncytial virus (RSV) is one of the most frequent causes of respiratory infections in children under 5 years of age, but its socioeconomic impact and burden in primary care settings is still little studied. During the 2022/2023 winter season, 55 pediatricians from five Italian regions participated in our community-based study. They collected a nasal swab for RSV molecular test from 650 patients under the age of 5 with acute respiratory infections (ARIs) and performed a baseline questionnaire. The clinical and socioeconomic burden of RSV disease in primary care was evaluated by two follow-up questionnaires completed by the parents of positive children on Days 14 and 30. RSV laboratory-confirmed cases were 37.8% of the total recruited ARI cases, with RSV subtype B accounting for the majority (65.4%) of RSV-positive swabs. RSV-positive children were younger than RSV-negative ones (median 12.5 vs. 16.5 months). The mean duration of symptoms for all children infected by RSV was 11.47 ± 6.27 days. We did not observe substantial differences in clinical severity between the two RSV subtypes, but RSV-A positive patients required more additional pediatric examinations than RSV-B cases. The socioeconomic impact of RSV infection was considerable, causing 53% of children to be absent from school, 46% of parents to lose working days, and 25% of families to incur extra costs. Our findings describe a baseline of the RSV disease burden in primary care in Italy before the introduction of upcoming immunization strategies.

Mpox reinfection: A rapid systematic review of case reports

BackgroundMpox re-emerged worldwide with the multi-country outbreaks that occurred in May 2022, threatening the public health of human beings. MethodsThis rapid systematic review summarized mpox reinfection cases documented. Electronic databases (PubMed, MedRxiv, and Social Science Research Network) were searched without time limitation, using the keywords “mpox,” “monkeypox,” & “reinfection,” “reoccur,” “reoccurrence,” “episode,” and “relapse”. All laboratory-confirmed cases of mpox reinfection published in the literature were included in this study. ResultsA total of seven publications (nine cases) from Africa, Europe, and South America were included. All mpox reinfection cases were male, with a median age of 36; 88.89% of cases had unprotected sexual behaviors with other males before each illness episode. The average onset interval between the two episodes was about 4 months. Perianal lesions and lymphadenopathy were major symptoms in both episodes, and no differences in clinical severity were reported between the two episodes. The mean duration of the two episodes was approximately 22 days and 13 days, respectively; which the mean duration of the second episode was shorter than the first infection (t = 2.17, p = 0.0487). Sexually transmitted infections were commonly concurrent among most cases, accounting for 55.6% and 77.8% in the two episodes, respectively. Full vaccination against mpox was rare among reinfection cases. ConclusionA second infection is possible even in a short period. Reinforcing monitoring, reducing high-risk behaviors, and heightening health education regarding mpox for high-risk populations are crucial to limit mpox spread, including persons with a history of mpox infection.

Clinical severity in Parkinson's disease is determined by decline in cortical compensation.

Dopaminergic dysfunction in the basal ganglia, particularly in the posterior putamen, is often viewed as the primary pathological mechanism behind motor slowing (i.e. bradykinesia) in Parkinson's disease. However, striatal dopamine loss fails to account for interindividual differences in motor phenotype and rate of decline, implying that the expression of motor symptoms depends on additional mechanisms, some of which may be compensatory in nature. Building on observations of increased motor-related activity in the parieto-premotor cortex of Parkinson patients, we tested the hypothesis that interindividual differences in clinical severity are determined by compensatory cortical mechanisms and not just by basal ganglia dysfunction. Using functional MRI, we measured variability in motor- and selection-related brain activity during a visuomotor task in 353 patients with Parkinson's disease (≤5 years disease duration) and 60 healthy controls. In this task, we manipulated action selection demand by varying the number of possible actions that individuals could choose from. Clinical variability was characterized in two ways. First, patients were categorized into three previously validated, discrete clinical subtypes that are hypothesized to reflect distinct routes of α-synuclein propagation: diffuse-malignant (n = 42), intermediate (n = 128) or mild motor-predominant (n = 150). Second, we used the scores of bradykinesia severity and cognitive performance across the entire sample as continuous measures. Patients showed motor slowing (longer response times) and reduced motor-related activity in the basal ganglia compared with controls. However, basal ganglia activity did not differ between clinical subtypes and was not associated with clinical scores. This indicates a limited role for striatal dysfunction in shaping interindividual differences in clinical severity. Consistent with our hypothesis, we observed enhanced action selection-related activity in the parieto-premotor cortex of patients with a mild-motor predominant subtype, both compared to patients with a diffuse-malignant subtype and controls. Furthermore, increased parieto-premotor activity was related to lower bradykinesia severity and better cognitive performance, which points to a compensatory role. We conclude that parieto-premotor compensation, rather than basal ganglia dysfunction, shapes interindividual variability in symptom severity in Parkinson's disease. Future interventions may focus on maintaining and enhancing compensatory cortical mechanisms, rather than only attempting to normalize basal ganglia dysfunction.

Clinical and electrophysiological characteristics of women with X-linked Charcot-Marie-Tooth disease.

X-Linked Charcot-Marie-Tooth disease type 1 (CMTX1) is characterized by gender differences in clinical severity. Women are usually clinically affected later and less severely than men. However, their clinical presentation appears to be heterogenous. Our aim was to extend the phenotypic description in a large series of women with CMTX1. We retrospectively evaluated 263 patients with CMTX1 from 11 French reference centers. Demographic, clinical, and nerve conduction data were collected. The severity was assessed by CMT Examination Score (CMTES) and Overall Neuropathy Limitations Scale (ONLS) scores. We looked for asymmetrical strength, heterogeneous motor nerve conduction velocity (MNCV), and motor conduction blocks (CB). The study included 137 women and 126 men from 151 families. Women had significantly more asymmetric motor deficits and MNCV than men. Women with an age of onset after 19 years were milder. Two groups of women were identified after 48 years of age. The first group represented 55%, with women progressing as severely as men, however, with a later onset age. The second group had mild or no symptoms. Some 39% of women had motor CB. Four women received intravenous immunoglobulin before being diagnosed with CMTX1. We identified two subgroups of women with CMTX1 who were over 48 years of age. Additionally, we have demonstrated that women with CMTX can exhibit an atypical clinical presentation, which may result in misdiagnosis. Therefore, in women presenting with chronic neuropathy, the presence of clinical asymmetry, heterogeneous MNCV, and/or motor CB should raise suspicion for X-linked CMT, particularly CMTX1, and be included in the differential diagnosis.

Molecular pathways identified from single nucleotide polymorphisms demonstrate mechanistic differences in systemic lupus erythematosus patients of Asian and European ancestry

Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disorder with a prominent genetic component. Individuals of Asian-Ancestry (AsA) disproportionately experience more severe SLE compared to individuals of European-Ancestry (EA), including increased renal involvement and tissue damage. However, the mechanisms underlying elevated severity in the AsA population remain unclear. Here, we utilized available gene expression data and genotype data based on all non-HLA SNP associations in EA and AsA SLE patients detected using the Immunochip genotyping array. We identified 2778 ancestry-specific and 327 trans-ancestry SLE-risk polymorphisms. Genetic associations were examined using connectivity mapping and gene signatures based on predicted biological pathways and were used to interrogate gene expression datasets. SLE-associated pathways in AsA patients included elevated oxidative stress, altered metabolism and mitochondrial dysfunction, whereas SLE-associated pathways in EA patients included a robust interferon response (type I and II) related to enhanced cytosolic nucleic acid sensing and signaling. An independent dataset derived from summary genome-wide association data in an AsA cohort was interrogated and identified similar molecular pathways. Finally, gene expression data from AsA SLE patients corroborated the molecular pathways predicted by SNP associations. Identifying ancestry-related molecular pathways predicted by genetic SLE risk may help to disentangle the population differences in clinical severity that impact AsA and EA individuals with SLE.

Comparative Analysis of Clinical and CT Findings in Patients with SARS-CoV-2 Original Strain, Delta and Omicron Variants.

To compare the clinical characteristics and chest CT findings of patients infected with Omicron and Delta variants and the original strain of COVID-19. A total of 503 patients infected with the original strain (245 cases), Delta variant (90 cases), and Omicron variant (168 cases) were retrospectively analyzed. The differences in clinical severity and chest CT findings were analyzed. We also compared the infection severity of patients with different vaccination statuses and quantified pneumonia by a deep-learning approach. The rate of severe disease decreased significantly from the original strain to the Delta variant and Omicron variant (27% vs. 10% vs. 4.8%, p < 0.001). In the Omicron group, 44% (73/168) of CT scans were categorized as abnormal compared with 81% (73/90) in the Delta group and 96% (235/245, p < 0.05) in the original group. Trends of a gradual decrease in total CT score, lesion volume, and lesion CT value of AI evaluation were observed across the groups (p < 0.001 for all). Omicron patients who received the booster vaccine had less clinical severity (p = 0.015) and lower lung involvement rate than those without the booster vaccine (36% vs. 57%, p = 0.009). Compared with the original strain and Delta variant, the Omicron variant had less clinical severity and less lung injury on CT scans.

Clinical severity of Omicron subvariants BA.1, BA.2, and BA.5 in a population-based cohort study in British Columbia, Canada.

The SARS-CoV-2 variant Omicron emerged in late 2021. In British Columbia (BC), Canada, and globally, three genetically distinct subvariants of Omicron, BA.1, BA.2, and BA.5, emerged and became dominant successively within an 8-month period. SARS-CoV-2 subvariants continue to circulate in the population, acquiring new mutations that have the potential to alter infectivity, immunity, and disease severity. Here, we report a propensity-matched severity analysis from residents of BC over the course of the Omicron wave, including 39,237 individuals infected with BA.1, BA.2, or BA.5 based on paired high-quality sequence data and linked to comprehensive clinical outcomes data between December 23, 2021 and August 31, 2022. Relative to BA.1, BA.2 cases were associated with a 15% and 28% lower risk of hospitalization and intensive care unit (ICU) admission (aHRhospital = 1.17; 95% confidence interval [CI] = 1.096-1.252; aHRICU = 1.368; 95% CI = 1.152-1.624), whereas BA.5 infections were associated with an 18% higher risk of hospitalization (aHRhospital = 1.18; 95% CI = 1.133-1.224) after accounting for age, sex, comorbidities, vaccination status, geography, and social determinants of health. Phylogenetic analysis revealed no specific subclades associated with more severe clinical outcomes for any Omicron subvariant. In summary, BA.1, BA.2, and BA.5 subvariants were associated with differences in clinical severity, emphasizing how variant-specific monitoring programs remain critical components of patient and population-level public health responses as the pandemic continues.

COVID-19 increased in Italian children in the autumn and winter 2021-2022 period when Omicron was the dominant variant.

We examined the prevalence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in children during the autumn and winter season from 1 September 2021 to 30 January 2022 and compared it with the same period in 2020-2021. This study was carried out int the paediatric emergency department (PED) of a tertiary Italian hospital. We compared the clinical and demographical features of all children who presented during the two study periods and tested positive for SARS-CoV-2. During the 2021-2022 autumn and winter season 5813 children presented to the PED, 19.0% were tested for SARS-CoV-2 and 133 (12.0%) of those tested positive. In 2020-2021, 2914 presented to the PED, 12.3% were tested, and 30 (8.3%) of those tested positive. There were no statistically significant differences in clinical severity during the two study periods, despite a higher percentage of neurological symptoms in 2020-2021. Of the SARS-CoV-2-positive cases, 29/133 (21.8%) were hospitalised during the 2021-2022 season and 10/30 (33.3%) during the previous one. Only 3/163 children required intensive care. The greater spread of SARS-CoV-2 was probably due to the greater transmissibility of the Omicron variant, but the symptoms were mild and only 3 children required intensive care.

Comparison of the Efficacy of Intramammary or Injectable Antibiotic Administration against Staphylococcal Mastitis in Ewes.

The objectives of the work were (a) to compare the efficacy of two routes for antibiotic administration in the treatment of mastitis in ewes and (b) to assess the potential importance of the timing of the initiation of the therapeutic regime on the outcome of the treatment. The ewes were allocated at random into three equal groups; intramammary inoculation with a Staphylococcus simulans isolate was performed, and clinical mastitis developed. The ewes in groups T1 (n = 6) and T2 (n = 6) were treated by the intramammary administration of ampicillin and dicloxacillin (two administrations with a 12-h interval). The ewes in group T3 (n = 6) were treated by the intramuscular injection of ampicillin and dicloxacillin (0.75 mL per 10 kg bodyweight, three injections with a 24-h interval). In the ewes in groups T1 and T3, treatment started immediately when the clinical signs of mastitis were first detected during the periodic examination of the ewes; in the ewes in group T2, treatment started 24 h after the clinical signs of mastitis were first detected. The animals were monitored clinically; mammary secretion samples were collected for bacteriological and cytological examinations. The median duration of the clinical signs was 4.75, 7.13, and 4.75 d for T1, T2, and T3; significant differences in clinical severity between the groups were seen until the 7th day post-treatment. The median duration of bacterial recovery was 3.25, 8.00, and 8.00 d for T1, T2, and T3; significant differences in the frequency of bacterial recovery between the groups were seen until (64.1%, 94.9%, and 96.2% of the samples) and after (2.9%, 16.7%, and 11.8%) the 7th day post-treatment. The median period required for the complete cure (clinical, bacteriological, and cytological) was shorter in the T1 than in the T2 and T3 ewe groups: 20.0, 32.0, and 24.5 d, respectively. The findings cover a gap in the available literature regarding the treatment of clinical mastitis in ewes. Early treatment resulted in the improved cure of the infection. The comparison of the intramammary and injectable routes for antibiotic administration indicated some benefit for the former, primarily in the post-treatment somatic cell counts.

I.02 Titin – The newly-emerged "titan" of the cardiac and skeletal muscle disease world

The advent of massively parallel sequencing made the routine analysis of enormous genes like <i>TTN</i> (titin) - the gene that encodes the largest protein in nature - finally feasible. As a direct consequence of the increasing use of this technology in the clinical diagnostic setting, it is now abundantly clear that <i>TTN</i> mutations are responsible several important skeletal muscle and cardiac disorders. Many of these disorders have a devastating lifelong impact on affected individuals and their families and are therefore health system priorities. We now know that heterozygous truncating <i>TTN</i> mutations are the most common genetic cause of dilated cardiomyopathy. In addition, heterozygous mutations in two very specific regions of <i>TTN</i> result in two different adult-onset skeletal muscle disorders: tibial muscular dystrophy and hereditary myopathy with early respiratory failure. Recessive titinopathies caused by mutations in both copies of <i>TTN</i> have recently emerged as one of the most common causes of congenital or early-onset muscle disease. Biallelic <i>TTN</i> mutations have also been identified in a growing number of patients with adolescent- and occasionally adult-onset muscle weakness. There are currently no available titinopathy drug treatments. Management is therefore limited to supportive care. In addition, it is strongly suspected that a significant number of "true" titinopathy patients remain without a genetic diagnosis because their <i>TTN</i> mutations have been missed by standard diagnostic approaches. Our understanding of the transcript- and protein-level impacts of patient mutations and the underlying basis of observed differences in clinical severity is also limited. This presentation will focus on recent clinical and research-based developments in the titinopathy field. We will also examine best practice <i>TTN</i> diagnostic approaches, challenges, and pitfalls. Likely future directions in titinopathy diagnosis, research and treatment development will also be explored.

Next generation personalized blood vessel‐on‐chip: Mimicking patient‐specific pathophysiology in sickle cell disease through blood‐derived endothelial progenitors

Advances in tissue engineering and organ‐chip technology have accelerated in vitro research of the vascular system. Incorporating patient‐derived endothelial cells either through direct tissue biopsies or stem cell differentiation techniques further enhance the impact of organ‐chips on precision medicine. However, these methods pose certain challenges and might be difficult to adopt in lab, thereby limiting the predictive power of organ‐chips. Here we report the use of Blood Outgrowth Endothelial Cells (BOECs) directly isolated from patient blood as an alternative to primary and iPSC‐derived endothelial cells for organ‐chip applications. BOECs exhibit the gold‐standard endothelial hallmarks of the “cobblestone” morphology in vitro. When compared to primary HUVECs and iPSC‐derived endothelial cells, healthy BOECs reveal similar levels of growth rates, migration capabilities, de novo vessel formation, response to fluid shear stress and exogenous cytokine inflammation in vitro. To study patient‐specificity, we derive BOECs from two sickle cell disease (SCD) patients with known differences in clinical severity of the disease. Through next generation RNA sequencing, differential gene expression (DGE) analysis and qRT‐PCR, we reveal that SCD patient‐derived BOECs are indeed activated and that the more severe SCD patient exhibited a greater magnitude of activation. This is further confirmed by real‐time recalcified whole blood perfusion through endothelialized vessel‐chips. Blood‐derived endothelial cells may be employed in preclinical research for developing more robust and personalized next‐generation disease models that can ultimately enable clinicians in identifying individuals at high risk of stroke or cardiovascular complications.

Roles Played by Stress-Induced Pathways in Driving Ethnic Heterogeneity for Inflammatory Skin Diseases.

Immune-mediated skin conditions (IMSCs) are a diverse group of autoimmune diseases associated with significant disease burden. Atopic dermatitis and psoriasis are among the most common IMSCs in the United States and have disproportionate impact on racial and ethnic minorities. African American patients are more likely to develop atopic dermatitis compared to their European American counterparts; and despite lower prevalence of psoriasis among this group, African American patients can suffer from more extensive disease involvement, significant post-inflammatory changes, and a decreased quality of life. While recent studies have been focused on understanding the heterogeneity underlying disease mechanisms and genetic factors at play, little emphasis has been put on the effect of psychosocial or psychological stress on immune pathways, and how these factors contribute to differences in clinical severity, prevalence, and treatment response across ethnic groups. In this review, we explore the heterogeneity of atopic dermatitis and psoriasis between African American and European American patients by summarizing epidemiological studies, addressing potential molecular and environmental factors, with a focus on the intersection between stress and inflammatory pathways.

Impact of previous cardiac conditions in prognosis and clinical management of patient with COVID-19 infection

Abstract Background Recent studies suggest a higher mortality rate because of COVID-19 in patients with previous cardiac conditions compared to those without. Given the limited resources of intensive care units (ICU) during the pandemic outbreak, this fact has important implications. Purpose The main purpose of this study was to compare the 30-day mortality of the COVID-19 infection in patients with and without previous cardiac conditions. The secondary end point was to assess the differences in clinical severity of the infection (as development of Acute Respiratory Distress Syndrome – ARDS) and ICU admission amongst these patients. Methods A total of 1708 consecutive patients were prospectively included. The inclusion criteria were: a confirmed positive diagnosis of COVID-19 infection by PCR and being admitted to our centre between 18th and 23rd March 2020 and 22nd August and 9th January 2021. Patients were classified in two groups according to the presence of previous cardiac conditions (defined as previous history of myocardial infarction, heart failure and atrial fibrillation). Other comorbidities were extensively explored and Charlson Comorbidity Index was calculated. A propensity-score matching was performed and 145 patients with previous cardiac conditions were matched with 145 patients without. Results The group of patients with a previous cardiac condition included 421 patients (24.6%). The crude analysis showed a higher 30-day mortality rate among patients with previous cardiac affections (35.6% vs. 14.6%, p&amp;lt;0.001). They were also less likely to be admitted to the ICU (9.8% vs. 6.2%, p=0.022) and had a higher prevalence ARDS (48.9% vs. 33.9%, p&amp;lt;0.001). In the matched cohort, there were no significant differences between both groups regarding mortality (24.8% in the group of patients with previous cardiac conditions vs. 31.0%, p=0.272) nor ARDS prevalence (50.3% vs. 53.1%, p=0.655). There was a trend toward patients with previous cardiac conditions to be less likely to be admitted to the ICU (4.8% vs. 9.7%, p=0.090). Conclusions Patients with a personal history of previous cardiac conditions were less likely to be admitted to the ICU. However, our results show that when comparing cohorts with similar comorbidity burden, a previous cardiopathy “per se” does not significantly increase the risk of death in patients with a concomitant COVID infection. Funding Acknowledgement Type of funding sources: None. Mortality unmatched vs matched cohort

Mutation location and IKs regulation in the arrhythmic risk of long QT syndrome type 1: the importance of the KCNQ1 S6 region.

Mutation type, location, dominant-negative IKs reduction, and possibly loss of cyclic adenosine monophosphate (cAMP)-dependent IKs stimulation via protein kinase A (PKA) influence the clinical severity of long QT syndrome type 1 (LQT1). Given the malignancy of KCNQ1-p.A341V, we assessed whether mutations neighbouring p.A341V in the S6 channel segment could also increase arrhythmic risk. Clinical and genetic data were obtained from 1316 LQT1 patients [450 families, 166 unique KCNQ1 mutations, including 277 p.A341V-positive subjects, 139 patients with p.A341-neighbouring mutations (91 missense, 48 non-missense), and 900 other LQT1 subjects]. A first cardiac event represented the primary endpoint. S6 segment missense variant characteristics, particularly cAMP stimulation responses, were analysed by cellular electrophysiology. p.A341-neighbouring mutation carriers had a QTc shorter than p.A341V carriers (477 ± 33 vs. 490 ± 44 ms) but longer than the remaining LQT1 patient population (467 ± 41 ms) (P < 0.05 for both). Similarly, the frequency of symptomatic subjects in the p.A341-neighbouring subgroup was intermediate between the other two groups (43% vs. 73% vs. 20%; P < 0.001). These differences in clinical severity can be explained, for p.A341V vs. p.A341-neighbouring mutations, by the p.A341V-specific impairment of IKs regulation. The differences between the p.A341-neighbouring subgroup and the rest of LQT1 mutations may be explained by the functional importance of the S6 segment for channel activation. KCNQ1 S6 segment mutations surrounding p.A341 increase arrhythmic risk. p.A341V-specific loss of PKA-dependent IKs enhancement correlates with its phenotypic severity. Cellular studies providing further insights into IKs-channel regulation and knowledge of structure-function relationships could improve risk stratification. These findings impact on clinical management.