Calcium plays a fundamental role in various signaling pathways and cellular processes in the human organism. In the nervous system, voltage-gated calcium channels such as L-type calcium channels (LTCCs) are critical elements in mediating neurotransmitter release, synaptic integration and plasticity. Dysfunction of LTCCs has been implicated in both aging and Alzheimer\'s Disease (AD), constituting a key component of calcium hypothesis of AD. As such, LTCCs are a promising drug target in AD. However, due to their structural and functional complexity, the mechanisms by which LTCCs contribute to AD are still unclear. In this review, we briefly summarize the structure, function, and modulation of LTCCs that are the backbone for understanding pathological processes involving LTCCs. We suggest targeting molecular pathways up-regulating LTCCs in AD may be a more promising approach, given the diverse physiological functions of LTCCs and the ineffectiveness of LTCC blockers in clinical studies.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV 2) or coronavirus disease 2019 (COVID-19) initially surfaced in December 2019 from Wuhan, China, sweeping the world with various strains, forcing the WHO to declare a pandemic epidemic in March 2020. Furthermore, COVID-19 manifests with a wide array of presentations from fever and fatigue to severe respiratory and cardiovascular complications. Post-COVID-19 syndrome is poorly understood affecting COVID-19 survivors at all levels of disease severity. The disease is most associated with post-discharge dyspnea and fatigue. However, other persistent symptoms as chest pains, palpitations, smell, and taste dysfunctions. Patients with high concentrations of CRP and creatinine in the acute phase of Covid-19 are more prone to cardiac sequelae. Therefore, high levels of cardiac-sensitive troponin and hypokalaemia can also be used for risk stratification. Furthermore, Cardiac damage can manifest as myocarditis, pericarditis, rhythm abnormalities. The use of different diagnostic modalities like electrocardiogram (ECG), echocardiogram, and cardiac magnetic resonance imaging (MRI)(CMR) to evaluate the myocardial damage were studied. However, Cardiovascular complications are a common manifestation of PASC, classification of severity of cardiac symptoms and the emergence of CMR as a diagnostic tool needs more evidence.

The intracellular calcium ions (Ca2+) act as second messenger to regulate gene transcription, cell proliferation, migration and death. Accumulating evidences have demonstrated that intracellular Ca2+ homeostasis is altered in cancer cells and the alteration is involved in tumor initiation, angiogenesis, progression and metastasis. Targeting derailed Ca2+ signaling for cancer therapy has become an emerging research area. This review summarizes some important Ca2+ channels, transporters and Ca2+-ATPases, which have been reported to be altered in human cancer patients. It discusses the current research effort toward evaluation of the blockers, inhibitors or regulators for Ca2+ channels/transporters or Ca2+-ATPase pumps as anti-cancer drugs. This review is also aimed to stimulate interest in, and support for research into the understanding of cellular mechanisms underlying the regulation of Ca2+ signaling in different cancer cells, and to search for novel therapies to cure these malignancies by targeting Ca2+ channels or transporters.