Low-Density Lipoprotein Receptor-Related Protein 8 at the Crossroad between Cancer and Neurodegeneration.

The low-density-lipoprotein receptors represent a family of pleiotropic cell surface receptors involved in lipid homeostasis, cell migration, proliferation and differentiation. The family shares common structural features but also has significant differences mainly due to tissue-specific interactors and to peculiar proteolytic processing. Among the receptors in the family, recent studies place low-density lipoprotein receptor-related protein 8 (LRP8) at the center of both neurodegenerative and cancer-related pathways. From one side, its overexpression has been highlighted in many types of cancer including breast, gastric, prostate, lung and melanoma; from the other side, LRP8 has a potential role in neurodegeneration as apolipoprotein E (ApoE) and reelin receptor, which are, respectively, the major risk factor for developing Alzheimer's disease (AD) and the main driver of neuronal migration, and as a γ-secretase substrate, the main enzyme responsible for amyloid formation in AD. The present review analyzes the contributions of LDL receptors, specifically of LRP8, in both cancer and neurodegeneration, pointing out that depending on various interactions and peculiar processing, the receptor can contribute to both proliferative and neurodegenerative processes.

Cutaneous Ulcer Caused by Apixaban Treatment Is Resolved after Replacement with Dabigatran.

Nowadays, novel oral anticoagulants (NOACs) have shown improved safety profile and efficacy compared to vitamin K antagonists in the prevention of thromboembolic events occurring during different pathological conditions. However, there are concerns and safety issues, mostly related to adverse events following interactions with other drugs, in real-world practice. We report the case of an 83-year-old woman who developed a non-bleeding leg ulcer not caused by trauma or other evident pathological conditions after 10 days of treatment with apixaban 5 mg/q.d. She was switched from apixaban to dabigatran and the leg ulcer rapidly improved and completely cicatrized in 40 days. The resolution of the ulcer and the toleration of dabigatran therapy suggest an apixaban-specific reaction; however, the pathological mechanism of ulcer onset is currently unclear. Careful evaluation of hospital databases of Molise region (Southern Italy) hospitals identified two similar cases between 2019 and 2021. These cases underline the necessity of careful post-marketing surveillance, considering the rapidly increasing number of patients treated with NOACs and patient's risk factors such as old age, high polypharmacy rate, co-morbidities, and peculiar genetic background related to NOACs pharmacokinetic features.

Reply to Sagliocco, O.; Betelli, M. Comment on "Fierro et al. Severe Hypotension, Bradycardia and Asystole after Sugammadex Administration in an Elderly Patient. Medicina 2021, 57, 79".

We thank Dr. Sagliocco and Dr. Betelli for their comments [...].

Severe Hypotension, Bradycardia and Asystole after Sugammadex Administration in an Elderly Patient.

Background and Objectives: Sugammadex is a modified γ-cyclodextrin largely used to prevent postoperative residual neuromuscular blockade induced by neuromuscular aminosteroid blocking agents. Although Sugammadex is considered more efficacious and safer than other drugs, such as Neostigmine, significant and serious complications after its administration, such as hypersensitivity, anaphylaxis and, more recently, severe cardiac events, are reported. Case presentation: In this report, we describe the case of an 80-year-old male with no medical history of cardiovascular disease who was scheduled for percutaneous nephrolithotripsy under general anesthesia. The intraoperative course was uneventful; however, the patient developed a rapid and severe hypotension, asystole and cardiac arrest after Sugammadex administration. Spontaneous cardiac activity and hemodynamic stability was restored with pharmacological therapy and chest compression. The patient was stabilized and discharged uneventfully on postoperative day 10. Conclusions: The potential causes of cardiac arrest after Sugammadex administration have been carefully considered, yet all indications point to Sugammadex as the direct causative agent. On the basis of laboratory and clinical tests, we can exclude among the cause of bradycardia, Kounis syndrome, acute myocardial infarction, coronary spasm and other arrhythmias, but not anaphylaxis. Although Sugammadex is considered an increasingly important option in the prevention of postoperative residual neuromuscular blockade, anesthesiologists should consider it a causative agent of cardiac arrest during surgery. This case highlights the necessity of increased pharmacovigilance and further studies to examine Sugammadex safety and mechanism through which it may cause severe bradycardia, hypotension and cardiac arrest.

Sudden Cardiac Death Caused by a Fatal Association of Hypertrophic Cardiomyopathy (MYH7, p.Arg719Trp), Heterozygous Familial Hypercholesterolemia (LDLR, p.Gly343Lys) and SARS-CoV-2 B.1.1.7 Infection.

Hypertrophic cardiomyopathy (HCM) and heterozygous familial hypercholesterolemia (HeFH), two of the most common genetic cardiovascular disorders, can lead to sudden cardiac death. These conditions could be complicated by concomitant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection as in the case herein described. A young amateur soccer player died in late October 2020 after a fatal arrhythmia and the autopsy revealed the presence of HCM with diffuse non-obstructive coronary disease. The molecular autopsy revealed a compound condition with a first mutation in the MYH7 gene (p.Arg719Trp) and a second mutation in the LDLR gene (p.Gly343Cys): both have already been described as associated with HCM and HeFH, respectively. In addition, molecular analyses showed the presence of SARS-CoV-2 lineage B.1.1.7 (UK variant with high titer in the myocardium. Co-segregation analysis within the family (n = 19) showed that heterozygous LDLR mutation was maternally inherited, while the heterozygous MYH7 genetic lesion was de novo. All family member carriers of the LDLR mutation (n = 13) had systematic higher LDL plasma concentrations and positive records of cardiac and vascular ischemic events at young age. Considering that HCM mutations are in themselves involved in the predisposition to malignant arrhythmogenicity and HeFH could cause higher risk of cardiac complications in SARS-CoV-2 infection, this case could represent an example of a potential SARS-CoV-2 infection role in triggering or unmasking inherited cardiovascular disease, whose combination might represent the cause of fatal arrhythmia at such a young age. Additionally, it can provide clues in dating the presence of the SARS-CoV-2 lineage B.1.1.7 in Northern Italy in the early phases of the second pandemic wave.

Proteases Upregulation in Sporadic Alzheimer's Disease Brain.

Certain proteases are involved in Alzheimer's disease (AD) and their erroneous control may contribute to the pathology onset and progression. In this study we evaluated the cerebral expression of eight proteases, involved in both AßPP processing and extracellular matrix remodeling. Among these proteases, ADAM10, ADAMTS1, Cathepsin D, and Meprin ß show a significantly higher mRNAs expression in sporadic AD subjects versus controls, while ADAMTS1, Cathepsin D, and Meprin ß show an increment also at the protein level. These data indicate that transcriptional events affecting brain proteases are activated in AD patients, suggesting a link between proteolysis and AD.

Complexity and Selectivity of γ-Secretase Cleavage on Multiple Substrates: Consequences in Alzheimer's Disease and Cancer.

The processing of the amyloid-ß protein precursor (AßPP) by ß- and γ-secretases is a pivotal event in the genesis of Alzheimer's disease (AD). Besides familial mutations on the AßPP gene, or upon its overexpression, familial forms of AD are often caused by mutations or deletions in presenilin 1 (PSEN1) and 2 (PSEN2) genes: the catalytic components of the proteolytic enzyme γ-secretase (GS). The "amyloid hypothesis", modified over time, states that the aberrant processing of AßPP by GS induces the formation of specific neurotoxic soluble amyloid-ß (Aß) peptides which, in turn, cause neurodegeneration. This theory, however, has recently evidenced significant limitations and, in particular, the following issues are debated: 1) the concept and significance of presenilin's "gain of function" versus "loss of function"; and 2) the presence of several and various GS substrates, which interact with AßPP and may influence Aß formation. The latter consideration is suggestive: despite the increasing number of GS substrates so far identified, their reciprocal interaction with AßPP itself, even in the AD field, is significantly unexplored. On the other hand, GS is also an important pharmacological target in the cancer field; inhibitors or GS activity are investigated in clinical trials for treating different tumors. Furthermore, the function of AßPP and PSENs in brain development and in neuronal migration is well known. In this review, we focused on a specific subset of GS substrates that directly interact with AßPP and are involved in its proteolysis and signaling, by evaluating their role in neurodegeneration and in cell motility or proliferation, as a possible connection between AD and cancer.