A protein that plays a critical role in regulation of blood volume, systemic vascular resistance, and cardiovascular homeostasis. ACE2 is present on the cells of many organs in the human body, particularly those of the lungs, arteries, heart, kidney, and gastrointestinal tract, and is a critical element of the renin-angiotensin biochemical pathway. SARS-CoV-2, the virus that causes COVID-19, exploits the ACE2 receptor to gain entry into cells.

A molecule that inhibits oxidative damage to DNA, proteins, and lipids in cells. Oxidative damage plays a role in the aging process, cancer, and neurodegeneration. Many vitamins and plant-based compounds are antioxidants.

A test used in laboratory medicine, pharmacology, environmental biology, and molecular biology to determine the content or quality of specific components.

A type of heart arrhythmia. Atrial fibrillation, also known as A-fib, is characterized by a rapid, irregular heartbeat. It occurs when the electrical signals that regulate blood flow between the upper and lower chambers of the heart become dysregulated. It is the most common form of heart arrhythmia.

A type of white blood cell. B cells, also known as B-lymphocytes, arise from the bone marrow. As components of the body's adaptive immune system, they present antigens for recognition by T cells and produce cytokines, which drive the body's inflammatory response.

A medication used to prevent and to treat malaria. It is also occasionally used for amebiasis that is occurring outside of the intestines, rheumatoid arthritis, and lupus erythematosus. Currently it is being researched as an antiretroviral in humans with HIV-1/AIDS, an agent in chemotherapy for cancer, and its ability to inhibit lysosomal degradation of protein products during autophagy.

In statistics, a confounder (also confounding variable or confounding factor) is a variable that is correlated (directly or inversely) to both the dependent variable and independent variable.

A variable that is related to one or more of the other variables in a study. A confounding factor can mask an association that exists between variables or demonstrate an association that does not exist. If confounding factors are not measured and considered, the findings of the study may be biased.

The end stage of heart disease, characterized by reduced capacity of the heart muscle to pump blood. Also referred to as heart failure, it represents the culmination of all forms of cardiovascular disease and affects nearly 65 million people worldwide.

A group of related viruses that cause illness in birds and mammals, including humans. Members of this group include SARS-CoV-1 (which causes severe acute respiratory syndrome, or SARS), MERS-CoV (which causes Middle East respiratory syndrome, or MERS), SARS-CoV-2 (which causes COVID-19), and HCoV-OC43 (which causes the common cold).

An infectious disease caused by the novel coronavirus SARS-CoV-2. COVID-19, or coronavirus disease 2019, was first identified in Wuhan, China, in late 2019. The disease manifests primarily as a lower respiratory illness, but it can affect multiple organ systems, including the cardiovascular, neurological, gastrointestinal, and renal systems. Symptoms include fever, cough, fatigue, shortness of breath, and loss of smell and taste. Some infected persons, especially children, are asymptomatic. Severe complications of COVID-19 include pneumonia, sepsis, acute respiratory distress syndrome, kidney failure, multiple organ dysfunction syndrome, and cytokine storm. Treatments currently involve symptom management and supportive care. Mortality varies by country and region, but approximately 6 percent of people living in the United States who are diagnosed with COVID-19 expire.[1] 1

Also known as cyclic AMP, or cAMP, a cell signaling molecule that regulates many aspects of cellular metabolism and function. Increases in intracellular levels of cAMP impair aspects of innate immune functions, including the generation of inflammatory mediators and the phagocytosis and destruction of pathogens.

A corticosteroid drug used to treat inflammation. Dexamethasone has demonstrated effectiveness in patients with COVID-19 who are mechanically ventilated or required supplemental oxygen.

A broad-spectrum antibiotic used in the treatment of bacterial infections. Doxycycline, commonly called “doxy,” is a bacteriostatic drug that slows bacterial growth by inhibiting protein production. The World Health Organization considers doxycycline an essential medicine because of its widespread applications and its use as a treatment against biothreats such as anthrax, tularemia, and plague.

Any of a group of complex proteins or conjugated proteins that are produced by living cells and act as catalyst in specific biochemical reactions.

Important for the endocrine enhancing properties of exercise. Exerkines are exercise-induced hormonal-like factors which mediate the systemic benefits of exercise through autocrine, paracrine, and/or endocrine properties.^[1]

The collective set of genetic instructions for a single organism. The genome is stored in an organism's DNA and provides all the information required for its function and survival.

A common antimalarial drug that is also used to treat rheumatoid arthritis and lupus. Hydroxychloroquine is relatively safe with a few side effects. In 2017, it was the 128th most prescribed medication in the United States with more than five million prescriptions. It was used to treat COVID-19 early in the pandemic, but multiple high-quality studies subsequently showed no benefit from the drug.

A critical element of the body’s immune response. Inflammation occurs when the body is exposed to harmful stimuli, such as pathogens, damaged cells, or irritants. It is a protective response that involves immune cells, cell-signaling proteins, and pro-inflammatory factors. Acute inflammation occurs after minor injuries or infections and is characterized by local redness, swelling, or fever. Chronic inflammation occurs on the cellular level in response to toxins or other stressors and is often “invisible.” It plays a key role in the development of many chronic diseases, including cancer, cardiovascular disease, and diabetes.

Experiments that are performed using cells or microorganisms outside of their normal biological context and are often done in a test tube or petri dish.

An essential mineral present in many foods. Iron participates in many physiological functions and is a critical component of hemoglobin. Iron deficiency can cause anemia, fatigue, shortness of breath, and heart arrhythmias.

An antiparasitic drug used to treat round worm infections. Ivermectin exerts both anti-viral and anti-inflammatory properties. It has been proposed as an adjunct treatment for COVID-19.

A form of RNA, transcribed from a single strand of DNA, that carries genetic information required for protein synthesis from DNA to the ribosomes.

A type of study that analyzes the data derived from multiple studies. Meta-analyses apply objective, statistical formulas to identify a common effect.

A drug commonly used for the treatment of type 2 diabetes. Metformin is in a class of antihyperglycemic drugs called biguanides. It works by decreasing gluconeogenesis in the liver, reducing the amount of sugar absorbed in the gut, and increasing insulin sensitivity. A growing body of evidence indicates that metformin modulates the aging processes to improve healthspan and extend lifespan. Furthermore, metformin may prevent genomic instability by scavenging reactive oxygen species, increasing the activities of antioxidant enzymes, inhibiting macrophage recruitment and inflammatory responses, and stimulating DNA damage responses and DNA repair.[1]

[1] Najafi, Masoud, et al. "Metformin: Prevention of genomic instability and cancer: A review." Mutation Research/Genetic Toxicology and Environmental Mutagenesis 827 (2018): 1-8.

A respiratory illness caused by the MERS-CoV coronavirus. MERS is a zoonotic illness, first isolated in bats and then transferred to camels and humans. Symptoms may be mild, moderate, or severe, and include fever, cough, diarrhea, and difficulty breathing.

A type of vaccine that contains the genetic material to encode a single viral protein that, when injected into the body, induces antibody production against the target protein. Because mRNA degrades easily, it must be encapsulated in lipid nanoparticles in order to be absorbed by cells and often must be delivered in multiple injections to promote optimal immune response.

One of four nitrogen-containing molecules that comprise DNA. A nucleotide consists of one of four chemicals, called a “base,” plus one molecule of sugar and one molecule of phosphoric acid. Nucleotides are typically identified by the first letter of their base names: adenine (A), cytosine (C), guanine (G), and thymine (T). They form specific pairs (A with T, and G with C), and their bonds provide the helical structure of the DNA strand.

Highly reactive molecules that have the ability to oxidize other molecules and cause them to lose electrons. Common oxidants are oxygen, hydrogen peroxide, and superoxide anion.

In general, anything that can produce disease. Typically, the term is used to describe an infectious agent such as a virus, bacterium, prion, fungus, or other microorganism.

A study in which people are randomly allocated to receive one of several clinical interventions. One of these interventions is the standard of comparison or control. The control may be a standard practice, a placebo, or no intervention at all.

An enzyme that facilitates the generation of complementary DNA. In viruses, reverse transcriptases convert viral RNA into a complementary DNA, which can then be integrated into the host’s genome. In humans, the reverse transcriptase telomerase maintains and extends the length of telomeres.

The virus that causes severe acute respiratory syndrome, or SARS. First identified in China in 2002, SARS-CoV-2 is a type of coronavirus. It was responsible for an epidemic that killed nearly 800 people worldwide.

The virus that causes COVID-19. SARS-CoV-2 is one of seven coronaviruses known to infect humans. Others include SARS-CoV-1 (which causes severe acute respiratory syndrome, or SARS) and MERS-CoV (which causes Middle East respiratory syndrome, or MERS). SARS-CoV2 exploits the angiotensin-converting enzyme 2, or ACE2, receptor to gain entry into cells. The ACE2 receptor is widely distributed among the body's tissues but is particularly abundant in lung alveolar epithelial cells and small intestine enterocytes. SARS-CoV-2 binds to a cell's ACE2 receptor and injects its genetic material (RNA) into the cytosol. Once inside, the viral RNA molecules are translated to produce RNA-dependent RNA polymerase, also known as replicase, the enzyme critical for the reproduction of RNA viruses. The viral RNA is then packaged into infective virion particles and released from the cell to infect neighboring cells.

An antibody that plays key roles in immunity. Secretory IgA is the most abundant antibody in the mucosal immune system, accounting for nearly 20 percent of serum immunoglobulin. It is crucial in protecting the intestinal epithelium from toxins and pathogenic microorganisms.

Environmental factors which may reduce reproductive success in a population and thus contribute to evolutionary change or extinction through the process of natural selection.

A type of white blood cell that plays critical roles in the body's adaptive immune response. T cells form in the bone marrow but mature in the thymus (hence the "T" designation). They destroy malignant cells by triggering apoptosis – a type of cellular self-destruct mechanism that rids the body of damaged or aged cells.

A condition in which a clot forms in a blood vessel. Thrombosis can occur in veins or arteries and can cause damage to the tissues supplied by the affected vessel. Symptoms include pain, swelling, chest pain, numbness or weakness, and altered mental state.

The highest level of intake of a given nutrient likely to pose no adverse health effects for nearly all healthy people. As intake increases above the upper intake level, the risk of adverse effects increases.

A potent water-soluble antioxidant found in citrus fruits. Vitamin C is an essential nutrient involved in tissue repair, neurotransmission, and immune system function. Also known as ascorbic acid.

A fat-soluble vitamin stored in the liver and fatty tissues. Vitamin D plays key roles in several physiological processes, such as the regulation of blood pressure, calcium homeostasis, immune function, and the regulation of cell growth. In the skin, vitamin D decreases proliferation and enhances differentiation. Vitamin D synthesis begins when 7-dehydrocholesterol, which is found primarily in the skin’s epidermal layer, reacts to ultraviolet light and converts to vitamin D. Subsequent processes convert D to calcitriol, the active form of the vitamin. Vitamin D can be obtained from dietary sources, too, such as salmon, mushrooms, and many fortified foods.

Volatile organic compound. An organic chemical that has a high vapor pressure at ordinary room temperature.