Identification of Novel Quinolone and Quinazoline Alkaloids as Phosphodiesterase 10A Inhibitors for Parkinson's Disease through a Computational Approach

Phosphodiesterases (PDEs) are vital in signal transduction, specifically by hydrolyzing cAMP and cGMP. Within the PDE family, PDE10A is notable for its prominence in the striatum and its regulatory function over neurotransmitters in medium-spiny neurons. Given the dopamine deficiency in Parkinson's disease (PD) that affects striatal pathways, PDE10A inhibitors could offer therapeutic benefits by modulating D1 and D2 receptor signaling. This study was motivated by the successful history of quinazoline/quinazoline scaffolds in the inhibition of PDE10A. This study involved detailed in silico evaluations through docking followed by pharmacological, pharmacophoric, and pharmacokinetic analyses, prioritizing central nervous system (CNS)-active drug criteria. Seven cyclic peptides, those featuring the quinazoline/quinazoline moiety at both termini, exhibited notably enhanced docking scores compared to those of the remaining alkaloids within the screened library. We identified 7 quinolines and 1 quinazoline including Lepadin G, Aspernigerin, CJ-13536, Aurachin A, 2-Undecyl-4(1H)-quinolone, Huajiaosimuline 3-Prenyl-4-prenyloxyquinolin-2-one, and Isaindigotone that followed the standard CNS active drug criteria. The dominant quinoline ring in our study and its related quinazoline were central to our evaluations; therefore, the pharmacophoric features of these scaffolds were highlighted. The top alkaloids met all CNS-active drug properties; while nonmutagenic and without PAINS alerts, many indicated potential hepatotoxicity. Among the compounds, Huajiaosimuline was particularly significant due to its alignment with lead-likeness and CNS-active criteria. Aspernigerin demonstrated its affinity for numerous dopamine receptors, which signifies its potential to alter dopaminergic neurotransmission that is directly related to PD. Interestingly, the majority of these alkaloids had biological targets primarily associated with G protein-coupled receptors, critical in PD pathophysiology. They exhibit superior excretion parameters and toxicity end-points compared to the standard. Notably, selected alkaloids demonstrated stability in the binding pocket of PDE10A according to the molecular dynamic simulation results. Our findings emphasize the potential of these alkaloids as PDE10A inhibitors. Further experimental studies may be necessary to confirm their actual potency in inhibiting PDE10A before exploring their therapeutic potential in PD.

Non-Obstructing Coronary Artery Ischaemia, An Underdiagnosed Silent Killer

Dear Madam, Ischemia due to Non-Obstructing Coronary Arteries (INOCA), formerly known as Prinzmetal Angina, is a condition that affects a significant number of people, especially in Pakistan. I have encountered several cases where patients exhibit stable angina symptoms, despite having normal or near-normal coronary angiograms. Among about 400,000 patients with suspected ischemic heart disease, the American College of Cardiology National Cardiovascular Data Registry found that only 37.6%   had obstructive coronary artery disease, and 39.2% had no evidence of coronary artery disease. The exact prevalence of INOCA is not well-known. (1) Moreover, a prior research study found that heart failure patients of South Asian origin had a higher prevalence of INOCA compared to other populations. (2) A recent meta-analysis revealed that approximately 50% of the patients with nonobstructive coronary artery disease had coronary microvascular disease (CMD) and/or coronary artery spasms, suggesting that a significant number of INOCA patients are not appropriately diagnosed in routine clinical practice. (3) This shows us the importance of INOCA and also suggests that we need to improve the diagnosis protocols that Pakistani physicians commonly use. INOCA and myocardial infarction with non-obstructive coronary artery disease (MINOCA) are underrecognized and underdiagnosed conditions with cardiovascular health implications. These conditions are associated with a higher risk of death from cardiovascular causes in Pakistan, as well as a greater burden on the healthcare system, due to frequent hospital admissions for persistent chest pain and invasive coronary angiographies that often yield negative results. We have to dive more into Invasive coronary angiography by doing the Comprehensive Physiologic Assessment, using a pressure sensing guidewire to measure FFR (Fractional Flow reserve) and CFR (Coronary Flow Reserve) to evaluate Epicardial Stenosis and Microvascular Angina respectively. Later on, CFT can also be performed to confirm the diagnosis of coronary microvascular dysfunction. (4) To ensure that we do not miss INOCA, we should also consider other tests that do not involve inserting a catheter into the heart. These tests include Transthoracic echocardiography, Cardiac MRI, and Cardiac PET. By doing these tests, we can determine if the patient has INOCA and what type of INOCA they have. These will help us to tailor our management plan in the best possible way and also help us to guide the patients on how to reduce their risk factors.

Inter-provincial migration in Pakistan, 1971-1981

The objectives of this paper are: "(1) To estimate the volume of net inter-provincial migration in Pakistan between 1971-1981 with the use of the census survival ratio method; and (2) to estimate selected demographic characteristics (age and sex) of the migrants."