Aging is a process we all go through. On one hand, aging is a good parameter of health, since it requires one to survive into late adulthood. In fact, many countries are worried that their populations are aging too well and that soon there will be more individuals who have retired than there are those who are still working.
On the other hand, aging has almost become a sort of taboo in our world today. A contributing factor to this is that we are constantly being photographed using high-resolution cameras on our phones, thus exposing the slightest flaw in our complexion. Wrinkles, hair loss, and cognitive decline are contemplated with horror, leading to the mushrooming of plastic surgery centers.
From a medical standpoint, aging is a topic that has consistently generated interest because it is at least in part a biological process.
“It is still a matter of debate whether aging is an adaptive and regulated process, or merely a consequence arising from a stochastic accumulation of harmful events that culminate in a global state of reduced fitness, risk for disease acquisition, and death,” Schmeer and colleagues wrote in Cells.
The debate surrounding aging is twofold: can we precisely identify all the factors that cause aging, and will that knowledge help us to halt or reverse the aging process? This is evidence that a part of the aging process is biologically programmed, while other parts are caused by environmental factors.
Scientists are also using more sophisticated tools to uncover the secrets of aging. “Application of artificial intelligence for the development of novel therapeutics and biomarker discovery have been actively highlighted,” Mkrtchyan and colleagues wrote in Aging 2020. “In particular, for the last couple of years, several aging clocks have been developed to predict chronological and biological age based on certain clinical parameters.”
Aging is a risk factor for countless morbidities. Hence, the effort to halt or reverse aging is not necessarily an exercise in vanity; instead, it can help improve the quality of life or prolong the lifespan of aging individuals.
Mimicking the Features of Aging
Some diseases mimic many features of aging. In Experimental Biology and Medicine, Idris and colleagues drew parallels between sickle cell disease (SCD) and symptoms of accelerated aging.
SCD results in the sickling of erythrocytes and is most commonly associated with painful vaso-occlusive crises. It can cause a spectrum of morbidities across a number of organs in the body. The heterogeneity of these morbidities is largely due to the varying levels of disease modifiers, such as the concentration of sickle and fetal hemoglobin, in patients with SCD.
“Accelerated aging is a state of fast decline in physical, biochemical, physiological, and organ functions, which is mostly associated with genetic, metabolic, or chronic diseases, and could lead to early death,” Idris and colleagues wrote.
Read more about SCD etiology
In view of this definition, it is easy to see why SCD can be compared to accelerated aging. SCD causes a decline in all of the parameters provided in the definition of accelerated aging above. As more patients with SCD survive into adulthood due to advancements in SCD therapies, the risk of disease accumulation increases. Studies have demonstrated that more than half of SCD patients eventually develop multiple end-organ complications, which are significantly associated with early death.
SCD causes organ damage due to repeated vaso-occlusion and chronic hemolysis. This repeated injury to the organs damages the ability of the organs to heal. The most common organ complications from SCD are pulmonary hypertension, nephropathy, priapism, and stroke.
Lesser-Known Effects of SCD
Let’s explore the lesser-known complications of SCD and see how they too mimic accelerated aging. Studies have revealed that young patients with SCD are at a higher risk of developing stroke. This is in contrast with the majority of young people, in which the incidence of stroke is very low. Having a stroke is associated with sensory, motor, and cognitive decline. This is comparable to aspects of accelerated cerebrovascular aging.
SCD is associated with a number of bone degenerative disorders, such as osteopenia, osteomyelitis, and osteoporosis. This is because patients with SCD tend to have lower activities of osteoblasts, which causes a rise in the number of aged neutrophils. This increases the likelihood of osteonecrosis and osteoarthritis. These symptoms are comparable to aspects of accelerated bone aging.
Read more about SCD prognosis
Another important aspect in which SCD is comparable to accelerated aging is in terms of the damage it causes to the spleen. Patients with SCD are at a higher risk of early-onset hyposplenism; they are also known to develop functional asplenia. Idris and colleagues wrote, “Therefore, the immune system of patients with SCD shows vulnerability especially to encapsulated microbes, akin to what is seen in the elderly.”
The point of highlighting the parallels between SCD and accelerated aging syndrome is to raise awareness of how young patients with SCD can be much older biologically and suffer from the same vulnerabilities as the elderly. As such, it is important to include diseases such as SCD into the scope of research on medical issues affecting the elderly.
Mkrtchyan GV, Abdelmohsen K, Andreux P, et al. ARDD 2020: from aging mechanisms to interventions. Aging (Albany NY). 2020;12(24):24484-24503. doi:10.18632/aging.202454
Schmeer C, Kretz A, Wengerodt D, Stojiljkovic M, Witte OW. Dissecting aging and senescence-current concepts and open lessons. Cells. 2019;8(11):1446. doi:10.3390/cells8111446
Idris IM, Botchwey EA, Hyacinth HI. Sickle cell disease as an accelerated aging syndrome. Exp Biol Med (Maywood). 2022;247(4):368-374. doi:10.1177/15353702211068522