Increased Oxidative Stress and Decreased Sirtuin-3 and FOXO3 Expression Following Carotid Artery Intimal Injury in Hyperlipidemic Yucatan Microswine

Hypercholesterolemia is a major risk factor for atherosclerosis as oxidized-low-density lipoproteins (ox-LDL) contribute to the formation of foam cells and inflammation. Increased immune cell infiltration and oxidative stress induce instability of a plaque. Rupture of the unstable plaque precipitates adverse ischemic events. Since reactive oxygen species (ROS) play a critical role in plaque formation and vulnerability, regulating ROS generation may have therapeutic potential. Sirtuins, specifically sirtuin-3 (SIRT3), are antigenic molecules that can reduce oxidative stress by reducing mitochondrial ROS production through epigenetic modulation. Lack of SIRT3 expression is associated with dysregulation of ROS and endothelial function following high-fat high-cholesterol diet. SIRT3 deacetylates FOXO3a (Forkhead transcription factor O subfamily member 3a) and protects mitochondria against oxidative stress which can lead to even further protective anti-oxidizing properties. This study was designed to investigate the association between hyperlipidemia, intimal injury, chronic inflammation, and the expression of NAD-dependent deacetylase SIRT-3, FOXO3, antioxidant genes, and oxidative stress in carotid arteries of hypercholesterolemic Yucatan microswine. We found that intimal injury in hypercholesterolemic state led to increased expression of oxidative stress, inflammation, neointimal hyperplasia, and plaque size and vulnerability, while decreasing anti-oxidative regulatory genes and mediators. The findings suggest that targeting the SIRT3-FOXO3a-oxidative stress pathway will have therapeutic significance.

Role of sirtuins in attenuating plaque vulnerability in atherosclerosis

Atherosclerosis is characterized by the development of intimal plaque, thrombosis, and stenosis of the vessel lumen causing decreased blood flow and hypoxia precipitating angina. Chronic inflammation in the stable plaque renders it unstable and rupture of unstable plaques results in the formation of emboli leading to hypoxia/ischemia to the organs by occluding the terminal branches and precipitate myocardial infarction and stroke. Such delibitating events could be controlled by the strategies that prevent plaque development or plaque stabilization. Despite the use of statins to stabilize plaques, there is a need for novel targets due to continuously increasing cases of cardiovascular events. Sirtuins (SIRTs), a family of signaling proteins, are involved in sustaining genome integrity, DNA damage response and repair, modulating oxidative stress, aging, inflammation, and energy metabolism. SIRTs play a critical role in modulating inflammation and involves in the development and progression of atherosclerosis. The role of SIRTs in relation to atherosclerosis and plaque vulnerability is scarcely discussed in the literature. Since SIRTs regulate oxidative stress, inflammation, and aging, they may also regulate plaque progression and vulnerability as these molecular mechanisms underlie the pathogenesis of plaque development, progression, and vulnerability. This review critically discusses the role of SIRTs in plaque progression and vulnerability and the possibility of targeting SIRTs to attenuate plaque rupture, focusing on the highlights in genomics, molecular pathways, and cell types involved in the underlying pathophysiology.

Mitochondrial Biogenesis as a Therapeutic Target for Rotator Cuff Tendon Tears

Rotator Cuff Injuries (RCI) are highly prevalent and characterized by shoulder pain, restricted shoulder movement, and difficulty with overhead activity, radiating pain in the deltoid muscle, and atrophy of the rotator cuff muscles. Increasing age, hand dominance, smoking, hypertension, hyperlipidemia, and obesity are common risk factors. Chronic inflammation plays a critical role in the underlying pathogenesis. RCI accounts for massive healthcare expenditure costing about $15,000 per repair, and over 4.5 million physician visits per year, however, there is still no therapeutic target to improve clinical outcomes. Mitochondrial biogenesis in response to inflammatory stimuli supports increased cellular energy requirements, cell proliferation, and differentiation. This suggests that mitochondrial biogenesis may play a role in healing RCI by serving as a protective factor against free oxygen species and promoting homeostasis within the rotator cuff. There is evidence highlighting the potential therapeutic benefits of mitochondrial biogenesis in various inflammatory diseases, but no study explored the role of mitochondrial biogenesis in rotator cuff tears. Since hypercholesterolemia is a risk factor for RCI, we investigated the effects of hypercholesterolemia on the expression of PGC-1α, a marker of mitochondrial biogenesis, in rotator cuff muscle. The findings revealed an increased gene and protein expression of inflammatory mediators and PGC-1α, suggesting enhanced inflammation and increased mitochondrial biogenesis due to hypercholesterolemia. Additional studies are warranted to further investigate the chronic effect of hyperlipidemia induced RCI to elucidate the cause of insufficient mitochondrial biogenesis unable to protect the rotator cuff and the therapeutic effect of promoting mitochondrial biogenesis.

A Review of Hematological Complications and Treatment in COVID-19

COVID-19, caused by SARS-CoV-2, and its variants have spread rapidly across the globe in the past few years, resulting in millions of deaths worldwide. Hematological diseases and complications associated with COVID-19 severely impact the mortality and morbidity rates of patients; therefore, there is a need for oversight on what pharmaceutical therapies are prescribed to hematologically at-risk patients. Thrombocytopenia, hemoglobinemia, leukopenia, and leukocytosis are all seen at increased rates in patients infected with COVID-19 and become more prominent in patients with severe COVID-19. Further, COVID-19 therapeutics may be associated with hematological complications, and this became more important in immunocompromised patients with hematological conditions as they are at higher risk of hematological complications after treatment. Thus, it is important to understand and treat COVID-19 patients with underlying hematological conditions with caution. Hematological changes during COVID-19 infection and treatment are important because they may serve as biomarkers as well as to evaluate the treatment response, which will help in changing treatment strategies. In this literature review, we discuss the hematological complications associated with COVID-19, the mechanisms, treatment groups, and adverse effects of commonly used COVID-19 therapies, followed by the hematological adverse events that could arise due to therapeutic agents used in COVID-19.

Role of NF-κB during Mycobacterium tuberculosis Infection

Mycobacterium tuberculosis (M. tb) causes tuberculosis infection in humans worldwide, especially among immunocompromised populations and areas of the world with insufficient funding for tuberculosis treatment. Specifically, M. tb is predominantly exhibited as a latent infection, which poses a greater risk of reactivation for infected individuals. It has been previously shown that M. tb infection requires pro-inflammatory and anti-inflammatory mediators to manage its associated granuloma formation via tumor necrosis factor-α (TNF-α), interleukin-12 (IL-12), interferon-γ (IFN-γ), and caseum formation via IL-10, respectively. Nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) has been found to play a unique mediator role in providing a pro-inflammatory response to chronic inflammatory disease processes by promoting the activation of macrophages and the release of various cytokines such as IL-1, IL-6, IL-12, and TNF-α. NF-κB's role is especially interesting in its mechanism of assisting the immune system's defense against M. tb, wherein NF-κB induces IL-2 receptors (IL-2R) to decrease the immune response, but has also been shown to crucially assist in keeping a granuloma and bacterial load contained. In order to understand NF-κB's role in reducing M. tb infection, within this literature review we will discuss the dynamic interaction between M. tb and NF-κB, with a focus on the intracellular signaling pathways and the possible side effects of NF-κB inactivation on M. tb infection. Through a thorough review of these interactions, this review aims to highlight the role of NF-κB in M. tb infection for the purpose of better understanding the complex immune response to M. tb infection and to uncover further potential therapeutic methods.