Autosomal Recessive Hypercholesterolemia: Long-Term Cardiovascular Outcomes

Background

Autosomal recessive hypercholesterolemia (ARH) is a rare lipid disorder characterized by premature atherosclerotic cardiovascular disease (ASCVD). There are sparse data for clinical management and cardiovascular outcomes in ARH.

A Functional Aryl Hydrocarbon Receptor Genetic Variant,Alone and in Combination with Parental Exposure,is a Risk Factor for Congenital Heart Disease

Recent experimental studies showed that ablation of the aryl hydrocarbon receptor (AhR) as well as its activation by exogenous ligands disrupt the molecular networks involved in heart formation and function, leading to congenital heart disease (CHD). However, no evidence is available about the role of AhR in humans. We assessed the prevalence of a functional AhR genetic variant (p.Arg554Lys) in CHD patients as well as its joint effects with parental exposure. A total of 128 CHD patients (76 males; age 6.2 ± 6.7 years) and 274 controls (160 males; age at birth) were genotyped for the AhR polymorphism by using the TaqMan^® Drug Metabolism Genotyping assay. Both case and control parents completed a structured questionnaire on demographic, lifestyle and preconception exposures. Genotype (p = 0.001) and allele (p < 0.0001) distributions of AhR p.Arg554Lys differed significantly between patients and controls. A significant elevated CHD risk was found under dominant (OR = 2.9, 95% CI 1.9–4.6, p < 0.0001) and additive genetic models (OR = 6.2, 95% CI 2–19, p = 0.001). There was a significant interaction between 554-Lys allele and paternal smoking exposure (OR_smoking = 1.6, 95% CI = 0.9–2.9; OR_allele = 2.6, 95% CI = 1.3–5; OR_interaction = 4.9, 95% CI = 2.4–9.9, p _interaction < 0.0001). Additionally, 554-Lys allele exacerbated the effect of maternal periconceptional exposure (OR_exposure = 1.6, 95% CI = 0.8–3; OR_allele = 2.6, 95% CI = 1.5–4.5; OR_interaction = 5.7; 95% CI = 2.6–12, p _interaction < 0.0001). Our findings showed that the AhR p.Arg554Lys polymorphism, alone and in combination with parental exposures, is associated with the CHD risk, highlighting the significant role of AhR in the cardiovascular development.     

Urinary secretion and extracellular aggregation of mutant uromodulin isoforms

Uromodulin is exclusively expressed in the thick ascending limb and is the most abundant protein secreted in urine where it is found in high-molecular-weight polymers. Its biological functions are still elusive, but it is thought to play a protective role against urinary tract infection, calcium oxalate crystal formation, and regulation of water and salt balance in the thick ascending limb. Mutations in uromodulin are responsible for autosomal-dominant kidney diseases characterized by defective urine concentrating ability, hyperuricemia, gout, tubulointerstitial fibrosis, renal cysts, and chronic kidney disease. Previous in vitro studies found retention in the endoplasmic reticulum as a common feature of all uromodulin mutant isoforms. Both in vitro and in vivo we found that mutant isoforms partially escaped retention in the endoplasmic reticulum and reached the plasma membrane where they formed large extracellular aggregates that have a dominant-negative effect on coexpressed wild-type protein. Notably, mutant uromodulin excretion was detected in patients carrying uromodulin mutations. Thus, our results suggest that mutant uromodulin exerts a gain-of-function effect that can be exerted by both intra- and extracellular forms of the protein.     

Arterio-venous gradient of endothelial progenitor cells across renal artery stenosis

A role for circulating progenitor cells have been recently demonstrated in many pathological conditions. Endothelial progenitor cells (EPCs) localize at sites of ischemia and stimulate neovasculogenesis. This small study was carried out to assess whether selective blood sampling during renal angiography could demonstrate an arterio-venous gradient of EPCs in 5 patients with renal artery stenosis. Surprisingly, we found that EPCs were more abundant in venous than in arterial blood, suggesting that the kidney subjected to chronic ischemia may become a source rather than a target of EPCs.     

Incidence of venous thromboembolism in rheumatoid arthritis,results from a “real-life” cohort and an appraisal of available literature

Rheumatoid arthritis (RA) is associated with an increased risk of venous thromboembolism (VTE) occurrence. In this work, we assessed the incidence and predictive factors of VTE in our “real-life” cohort of RA patients. To contextualize our results, we reviewed the available literature about this topic.We performed a retrospective analysis of prospectively followed-up patients with RA attending our Rheumatologic Clinic between January 2010 and December 2020. Each patient was investigated for VTE occurrence. Incident cases were reported as incidence proportion and incidence rate per 1000 person-years at risk. Possible predictive factors were also exploited by regression analyses. Available literature about this topic was also assessed.In this evaluation, 347 consecutive patients without previous evidence of VTE, attending our Rheumatologic Clinic from 2010 to 2020, were studied. In our “real-life” cohort, the incidence proportion of VTE was 3.7% (2.7–4.7%) and considering over 1654 person-years, an incidence rate of 7.8 × 1000 (2.5–11.7). Exploratively assessing predictive factors in our cohort, older age (hazard ratio [HR] 1.07, 95% confidence interval [CI] 1.01–1.14, p = .015), higher body mass index (HR 1.37, 95% CI 1.04–1.80, P = .026), and longer disease duration (HR 1.11, 95% CI 1.03–1.20, P = .006) resulted to be significant predictors of VTE occurrence during the follow-up.In our “real-life” cohort, VTE burden has been suggested in patients with RA. Comparing our results with previous data derived from randomized controlled trials and administrative data, some different findings were retrieved about incidence of VTE. Assessing predictive factors, older age, higher body mass index, and longer disease duration resulted to be significant predictors of VTE occurrence during the follow-up. Taking together these observations, a further evaluation of this issue on specific designed studies is needed to provide more generalizable results to the daily clinical practice.     

p70S6 kinase mediates breast cancer cell survival in response to surgical wound fluid stimulation

In early breast cancer, local relapses represent a determinant and not simply an indicator of risk for distant relapse and death. Notably, 90% of local recurrences occur at or close to the same quadrant of the primary cancer. Relevance of PI3K/mTOR/p70S6K signaling in breast tumorigenesis is very well documented. However, the pathway/s involved in the process of breast cancer local relapse are not well understood. The ribosomal protein p70S6K has been implicated in breast cancer cell response to post‐surgical inflammation, supporting the hypothesis that it may be crucial also for breast cancer recurrence. Here, we show that p70S6K activity is required for the survival of breast cancer cells challenged in “hostile” microenvironments. We found that impairment of p70S6K activity in breast cancer cells strongly decreased their tumor take rate in nude mice. In line with this observation, if cells were challenged to grow in anchorage independence or in clonogenic assay, growth of colonies was strongly dependent on an intact p70S6K signaling. This in vitro finding was particularly evident when breast cancer cells were grown in the presence of wound fluids harvested following surgery from breast cancer patients, suggesting that the stimuli present in the post‐surgical setting at least partially relied on activity of p70S6K to stimulate breast cancer relapse. From a mechanistic point of view, our results indicated that p70S6K signaling was able to activate Gli1 and up‐regulate the anti‐apoptotic protein Bcl2, thereby activating a survival response in breast cancer cells challenged in hostile settings. Our work highlights a previously poorly recognized function of p70S6K in preserving breast cancer cell survival, which could eventually be responsible for local relapse and opens the way to the design of new and more specific therapies aiming to restrain the deleterious effects of wound response.