Hypertension is undoubtedly the most prevalent cardiovascular disease in the world. Recent data estimate that about 1 billion adults globally have hypertension. Hypertension directly contributes to heart failure and stroke and catalyzes the onset of heart attack, renal failure, and peripheral vascular disease.
What is Hypertension?
Hypertension or high blood pressure is a common condition in which the long term force of the blood against the artery walls is high enough that it may eventually cause health problems, such as heart disease.
Blood pressure is determined both by the amount of blood our heart pumps and the amount of resistance to blood flow in our arteries. The more blood the heart pumps and the narrower the arteries, the higher the blood pressure. A blood pressure reading is given in millimeters of mercury (mm Hg). It has 2 numbers:
- Top number (systolic pressure). The first, or upper number measures the pressure in our arteries when our heart beats.
- Bottom number (diastolic pressure). The second, or lower number measures the pressure in our arteries between beats.
High blood pressure can be present for years without any symptoms. Uncontrolled high blood pressure increases your risk of serious health problems, including heart attack and stroke.
Hypertension is diagnosed if, when it is measured on two different days, the systolic blood pressure readings on both days is ≥140 mmHg and/or the diastolic blood pressure readings on both days is ≥90 mmHg.
What are Common Symptoms of Hypertension?
The majority of people does not have any signs of symptoms, even if the blood pressure readings are dangerously high.
Some people may have headaches, shortness of breath or nosebleeds, but these signs and symptoms aren’t specific and usually don’t occur until high blood pressure has reached a severe or life-threatening stage.
What Causes Hypertension?
There are 2 types of hypertension:
- Primary or Essential Hypertension: For most adults there’s no identifiable cause of high blood pressure. This type of hypertension is called primary or essential and tends to develop gradually over the years. It has a genetic component.
- Secondary Hypertension: Some people have high blood pressure caused by an underlying condition. This type of hypertension tends to appear suddenly and cause higher blood pressure than does primary hypertension. Some conditions that can cause secondary hypertension are:
- Obstructive sleep apnea.
- Kidney disease.
- Adrenal gland tumors.
- Congenital defects.
- Birth control pills, decongestants.
- Cocaine and amphetamines.
What are the Risk Factors for Hypertension?
Some factors can increase the likelihood of your developing hypertension, some of them are:
- Age. The risk factor increases as we age. Until the age of 64, high blood pressure is more common in men, but women are more likely to develop hypertension after 65. This is due to the protection that estrogen gives women, protection that is lost when they enter menopause.
- Race. Hypertension is more common among people of African heritage.
- Family history. It has a genetic component and tends to run in families.
- Obesity. Being overweight or obese increases the blood that is need to supply oxygen and nutrients to tissues. As the amount of blood flow through our blood vessels increases, so does the pressure on the artery walls.
- Being Sedentary. People who are inactive tend to have higher heart rates, which increases the force the heart must work with each contraction and the stronger the force in the arteries. It also increases the risk of being overweight.
- Smoking. Not only does it immediately increase blood pressure temporarily, but it also can cause damage to artery walls.
- Sodium in diet. Potassium helps balance the amount of sodium in our cells. If we don’t get enough potassium or lose too much potassium due to dehydration or other health conditions, sodium builds up in the blood.
Excessive pressure in the artery walls can damage the blood vessels as well as organs. The higher the blood pressure and the longer it goes uncontrolled, the greater the damage.
Some complications can include heart attack or stroke, aneurysms, heart failure, chronic kidney disease, vision loss, metabolic syndrome and even dementia.
Current Treatment Options
To date, in addition to conventional drug treatment, the major therapeutic strategies for controlling hypertension have focused on lifestyle changes, such as regular physical activity, lower intake of saturated fats, salt, and alcohol, stress management, and smoking cessation.
Despite pharmacological treatment being effective, low treatment adherence makes hypertension difficult to control. Cultural, social, and economic factors substantially contribute to low adherence to therapy. A large proportion of patients are dissatisfied with their treatment and thus continuously exposed to further disease risk.
Stem Cell Therapy
Recently, cell based therapy has gained interest as a potential therapeutic alternative. Stem-cell therapy is a potentially promising strategy for the treatment of various cardiovascular diseases, including stroke, heart failure, and acute myocardial infarction.
Different studies have shown that stem cell transplantation improves cardiovascular function by releasing several paracrine signals. Paracrine signaling assists with maintaining cellular homeostasis through direct or distant connections and the release of different active substances. Stem cells also produce extracellular vesicles, called exosomes, that carry lipids, proteins, and nucleic acids, including DNA, miRNA, and non-coding RNA. Exosomes are in close contact with cardiac cells and carry different active substances into the cells.
Although only a few clinical trials have investigated the effects of cell therapy on hypertension, the effects of cell therapy on portal and pulmonary hypertension are well documented in the literature. A study conducted in 31 patients who were intravenously treated with Bone marrow Mesenchymal stem cells presented improvements in the mean pulmonary artery pressure, pulmonary vascular resistance and cardiac output.
Hypertension is a multifactorial polygenic disease for which identifying therapeutic targets, especially at the beginning of the disease, is extremely difficult. Hypertensive disease involves complex molecular mechanisms and not simply functional alterations of a single target organ.
Cell therapy is revolutionizing not only science but also patient-centered therapeutic approaches, thus making medicine more predictive, proactive, preventive, and personalized. Stem cell therapy may become an effective therapeutic alternative for the treatment of hypertensive patients with several lesions in target organs due to its potential to modulate the inflammatory response, paracrine signal mechanisms and regenerative properties. For the successful clinical translation of this technology, further animal studies and clinical trials that use standardized protocols are needed.
Gasparotto , A., & dos Reis , F. A. (2018). Cell-based therapy for hypertension: challenges and perspectives. Current Pharmaceutical Design, 24.
Mills, K.T., Stefanescu, A. & He, J. The global epidemiology of hypertension. Nat Rev Nephrol 16, 223–237 (2020). https://doi.org/10.1038/s41581-019-0244-2.