Mediators of Black-White inequities in cardiovascular mortality among survivors of 18 cancers in the USA.

BACKGROUND: This study aims to quantify Black-White inequities in cardiovascular disease (CVD) mortality among US survivors of 18 adult-onset cancers and the extent to which these inequities are explained by differences in socio-economic and clinical factors. METHODS: Survivors of cancers diagnosed at ages 20-64 years during 2007-16 were identified from 17 Surveillance, Epidemiology and End Results registries. Associations between race and CVD mortality were examined using proportional hazards models. Mediation analyses were performed to quantify the contributions of potential mediators, including socio-economic [health insurance, neighbourhood socio-economic status (nSES), rurality] and clinical (stage, surgery, chemotherapy, radiotherapy) factors. RESULTS: Among 904 995 survivors, 10 701 CVD deaths occurred (median follow-up, 43 months). Black survivors were more likely than White survivors to die from CVD for all 18 cancers with hazard ratios ranging from 1.30 (95% CI = 1.15-1.47) for lung cancer to 4.04 for brain cancer (95% CI = 2.79-5.83). The total percentage mediations (indirect effects) ranged from 24.8% for brain (95% CI=-5.2-59.6%) to 99.8% for lung (95% CI = 61.0-167%) cancers. Neighbourhood SES was identified as the strongest mediator for 14 cancers with percentage mediations varying from 25.0% for kidney cancer (95% CI = 14.1-36.3%) to 63.5% for lung cancer (95% CI = 36.5-108.7%). Insurance ranked second for 12 cancers with percentage mediations ranging from 12.3% for leukaemia (95% CI = 0.7-46.7%) to 31.3% for thyroid cancer (95% CI = 10.4-82.7%). CONCLUSIONS: Insurance and nSES explained substantial proportions of the excess CVD mortality among Black survivors. Mitigating the effects of unequal access to care and differing opportunities for healthy living among neighbourhoods could substantially reduce racial inequities in CVD mortality among cancer survivors.

Hemodynamic effects of COVID-19 vaccination in hospitalized patients awaiting heart transplantation.

Background: The hemodynamic effects of pre-transplant vaccination against COVID-19 among heart transplant candidates hospitalized for advanced heart failure remains unknown. Methods: A retrospective chart review was conducted at a high-volume transplant center from January through December 2021. 22 COVID-19 vaccination events occurred among patients hospitalized for decompensated heart failure while awaiting transplantation. Primary outcomes included inotrope and vasopressor dosages. Secondary outcomes included vital signs, pulmonary artery catheter measurements, diuretic dosages, and renal function. Data were extracted 24 h before through 72 h after vaccination. Results: One of 22 vaccination events was associated with hemodynamic changes requiring increased inotropic and vasopressor support post-vaccination. In all other cases, transient hemodynamic changes occurred without need for escalated therapy. Conclusions: COVID-19 vaccination can be administered safely to most critically ill patients with advanced heart failure including those awaiting transplantation. All patients should be monitored closely as some may be susceptible to significant hemodynamic changes.

Understanding the biological mechanisms of cancer treatment-induced cardiac toxicity.

While many strides have been made in the multidisciplinary science of Cardio-Oncology, gaps in knowledge remain despite these advances to identify optimal strategies of detection and treatment of cancer treatment-associated cardiotoxicity. Many opportunities are available for advocates from all avenues of the field to transform cardio-oncology from a reactionary to a preventative science.

Inequity in Cardio-Oncology: Identifying Disparities in Cardiotoxicity and Links to Cardiac and Cancer Outcomes.

Minority and underresourced communities experience disproportionately high rates of fatal cancer and cardiovascular disease. The intersection of these disparities within the multidisciplinary field of cardio-oncology is in critical need of examination, given the risk of perpetuating health inequities in the growing vulnerable population of patients with cancer and cardiovascular disease. This review identifies 13 cohort studies and 2 meta-analyses investigating disparate outcomes in treatment-associated cardiotoxicity and situates these data within the context of oncologic disparities, preexisting cardiovascular disparities, and potential system-level inequities. Black survivors of breast cancer have elevated risks of cardiotoxicity morbidity and mortality compared with White counterparts. Adolescent and young adult survivors of cancer with lower socioeconomic status experience worsened cardiovascular outcomes compared with those of higher socioeconomic status. Female patients treated with anthracyclines or radiation have higher risks of cardiotoxicity compared with male patients. Given the paucity of data, our understanding of these racial and ethnic, socioeconomic, and sex and gender disparities remains limited and large-scale studies are needed for elucidation. Prioritizing this research while addressing clinical trial inclusion and access to specialist care is paramount to reducing health inequity.

Myopathy associated LDB3 mutation causes Z-disc disassembly and protein aggregation through PKCα and TSC2-mTOR downregulation.

Mechanical stress induced by contractions constantly threatens the integrity of muscle Z-disc, a crucial force-bearing structure in striated muscle. The PDZ-LIM proteins have been proposed to function as adaptors in transducing mechanical signals to preserve the Z-disc structure, however the underlying mechanisms remain poorly understood. Here, we show that LDB3, a well-characterized striated muscle PDZ-LIM protein, modulates mechanical stress signaling through interactions with the mechanosensing domain in filamin C, its chaperone HSPA8, and PKCα in the Z-disc of skeletal muscle. Studies of Ldb3Ala165Val/+ mice indicate that the myopathy-associated LDB3 p.Ala165Val mutation triggers early aggregation of filamin C and its chaperones at muscle Z-disc before aggregation of the mutant protein. The mutation causes protein aggregation and eventually Z-disc myofibrillar disruption by impairing PKCα and TSC2-mTOR, two important signaling pathways regulating protein stability and disposal of damaged cytoskeletal components at a major mechanosensor hub in the Z-disc of skeletal muscle.

Z-disc-associated, alternatively spliced, PDZ motif-containing protein (ZASP) mutations in the actin-binding domain cause disruption of skeletal muscle actin filaments in myofibrillar myopathy.

The core of skeletal muscle Z-discs consists of actin filaments from adjacent sarcomeres that are cross-linked by α-actinin homodimers. Z-disc-associated, alternatively spliced, PDZ motif-containing protein (ZASP)/Cypher interacts with α-actinin, myotilin, and other Z-disc proteins via the PDZ domain. However, these interactions are not sufficient to maintain the Z-disc structure. We show that ZASP directly interacts with skeletal actin filaments. The actin-binding domain is between the modular PDZ and LIM domains. This ZASP region is alternatively spliced so that each isoform has unique actin-binding domains. All ZASP isoforms contain the exon 6-encoded ZASP-like motif that is mutated in zaspopathy, a myofibrillar myopathy (MFM), whereas the exon 8-11 junction-encoded peptide is exclusive to the postnatal long ZASP isoform (ZASP-LΔex10). MFM is characterized by disruption of skeletal muscle Z-discs and accumulation of myofibrillar degradation products. Wild-type and mutant ZASP interact with α-actin, α-actinin, and myotilin. Expression of mutant, but not wild-type, ZASP leads to Z-disc disruption and F-actin accumulation in mouse skeletal muscle, as in MFM. Mutations in the actin-binding domain of ZASP-LΔex10, but not other isoforms, cause disruption of the actin cytoskeleton in muscle cells. These isoform-specific mutation effects highlight the essential role of the ZASP-LΔex10 isoform in F-actin organization. Our results show that MFM-associated ZASP mutations in the actin-binding domain have deleterious effects on the core structure of the Z-discs in skeletal muscle.