Hello, I am Jessica. Welcome back to my "Hypertension Medical Course".
We have covered most of the knowledge about the "Four Highs," but there
is one unavoidable question: What is the relationship among the "Four
Highs"?
The Basis of Comorbidity in the Four Highs
According to the 2021 "China Cardiovascular Health and Disease Report,"
there are currently 245 million people with hypertension, 400 million
with hyperlipidemia, 670 million with hyperglycemia, and 200 million
with hyperuricemia in China. Globally, 70% of annual deaths are related
to these four conditions. The "Four Highs" are the greatest obstacles
on our path to longevity.
What do these numbers mean? On the surface, many Chinese adults have
two or more of these conditions.
More importantly, consider ourselves. Statistically, we are likely to
develop one of these conditions in a few years, then another in two or
three years, and then another, like Thanos collecting Infinity Stones.
Unfortunately, after a few years—or if lucky, decades—our most probable
cause of death will be diseases triggered by these "Four Highs".
So, why do the "Four Highs" grow together like mushrooms, suppressing
one only for another to emerge? Is there a common underlying soil—a
basis for comorbidity? This is the question we address in this chapter.
Clearly, this is not a simple, isolated issue but a complex,
multifaceted problem. The origins and mechanisms of the "Four Highs"
differ, and their intertwined stories have been discussed across four
courses.
Uric Acid and Blood Pressure
This issue is particularly suited to be explained through
hyperuricemia, as it most readily induces and connects with the other
three conditions. While the other three also interact, hyperuricemia
stands out.
Let’s first look at uric acid and blood pressure. Recall the RASS
system that regulates blood pressure. The central processing unit of
this system is in the kidneys, which receive various signals from the
body, analyze them, and determine how much blood pressure needs to be
raised to meet bodily demands, then produce a series of substances to
elevate blood pressure.
You’ll find that the RASS system acts as a bridge, connecting physical
and chemical changes in the blood, blood pressure, water, electrolytes,
hormones, as well as blood sugar, lipids, and uric acid, achieving
bodily balance and coordination.
Uric acid is one of the signals processed by the RASS system. Elevated
uric acid disrupts this system. Moreover, increased uric acid excretion
damages kidney function, directly affecting the RASS center. Both
factors lead to elevated blood pressure.
Additionally, recent research shows that RASS regulation is
bidirectional. Bodily disorders can raise blood pressure via RASS,
and elevated blood pressure can, in turn, damage kidney function
through RASS, worsening these disorders—especially those requiring
renal excretion, like uric acid. This is why, among the "Four Highs,"
hyperuricemia and hypertension are most closely linked.
Uric Acid, Lipids, and Glucose
Now, let’s examine the impact of uric acid on lipids and glucose.
Hyperuricemia is a protein metabolism disorder, hyperlipidemia is a fat
metabolism disorder, and hyperglycemia is a carbohydrate metabolism
disorder. These three share a common soil called "metabolic
syndrome", meaning a comprehensive metabolic problem.
Different cells in our body have varying nutritional needs—some tissues
need more fat for cold resistance, some need more glucose for mental
activity, and some need more protein for muscle growth. Thus, the
metabolic pathways for these three energy sources inevitably interact.
Because of these interactions, any disorder in the metabolism of
protein, fat, or carbohydrate affects the other two.
When you have hyperuricemia, the oxidative properties of uric acid
greatly increase the likelihood of lipid oxidation. Normal lipids do
not accumulate on vessel walls as plaques, but oxidized lipids are
adept at forming plaques. This means that if you only have
hyperlipidemia, plaque formation takes five to ten years, but if
combined with hyperuricemia or hyperglycemia, it may take just three to
five years.
We also observe that hyperuricemia patients are particularly prone to
diabetes. Why? Studies show that elevated uric acid makes cells less
sensitive to insulin. Normally, one unit of insulin can degrade a
certain amount of glucose, but now three units are insufficient,
leading to insulin resistance. The body secretes more insulin until it
is exhausted, resulting in type II diabetes.
*The key to "metabolic syndrome" is insulin resistance.* This is
understandable, as all energy metabolism in the body, when utilized by
cells, must be converted to glucose. Thus, the glucose-insulin system
is the fundamental energy supply for every cell. Any metabolic disorder
ultimately manifests as insulin resistance, affecting cellular energy
utilization.
Whether uric acid, glucose, or lipids are elevated, all worsen insulin
resistance, disrupting energy utilization and turning incoming energy
into a burden. Moreover, uric acid itself is an oxidant; excess amounts
increase systemic oxidative stress, triggering a series of problems.
The Common Outcome of the Four Highs
In summary, the "Four Highs" lead to common outcomes through two
harmful pathways: the RASS system and insulin resistance.
What are these common outcomes? In our "Four Highs" medical courses,
regardless of which condition is discussed, the most frequent outcomes
are myocardial infarction, cerebral infarction, coronary heart
disease, and renal failure.
Why these outcomes? The reason is simple: all pathological changes from
the "Four Highs" fall into two categories.
One is physical changes in the blood, such as hypertension—changes in
blood pressure.
The other is chemical changes in the blood, such as hyperglycemia,
hyperlipidemia, and hyperuricemia—metabolic disorders caused by excess
carbohydrates, fats, and proteins.
But whether physical or chemical, these changes occur in the blood
vessels, so the damage is borne by the vasculature. Especially vessels
with high blood flow and organs with high demand—heart, brain,
kidneys—suffer the most. Thus, regardless of which condition is
elevated, the outcomes are largely the same.
How does this damage occur? No matter which condition, the adverse
outcome is due to inflammatory reactions.
This inflammation is not the same as a wound infection, where external
bacteria fight the immune system. Here, the immune system attacks the
body itself, targeting healthy tissues. In a bacterial infection, the
fight ends when the bacteria are defeated; in auto-inflammation, the
battle is endless, leading to mutual destruction.
This battle is real, but its cause is abstract. You can’t understand it
just by looking at tangible entities; you must view it from the
perspective of balance.
Our bodies are products of evolution, surviving through adaptation and
stress responses. Adaptation helps us survive changing environments,
while stress responses help us cope with immediate dangers. Both are
fundamental to life.
Why have the "Four Highs" become a problem? The core is how our bodies,
shaped by yesterday, adapt to today’s changes. The stress we
face—physical and psychological—has changed dramatically.
Physically, we used to alternate between hunger and fullness; now,
every meal is energy surplus.
Psychologically, we used to deal with sudden threats like a lion;
now, we face constant, varied pressures daily.
The speed and magnitude of these changes are staggering—like going from
a hand-cranked phone to the latest iPhone in the blink of an eye. How
can the body keep up?
These external changes translate into internal changes—energy
metabolism, nervous system—anything the body can’t adapt to quickly
enough triggers stress responses. For the "Four Highs," elevated blood
pressure, glucose, lipids, or uric acid all trigger stress. The body
expresses this stress through inflammation, protecting itself from
harm.
But who knew these external changes would persist year after year?
Chronic inflammation accumulates damage, eventually overwhelming us.
After years in medicine, I used to believe only tangible scientific
advances could change the world. Later, I realized a broader
perspective is needed to find answers, break through theories, and
grow.
Now you understand the bridges connecting the "Four Highs" and their
common soil. It’s clear that the "Four Highs" prosper and suffer
together.
Indeed, research shows that prevention and treatment of the "Four
Highs" are interconnected. For example, if we control hyperuricemia
well, hypertension is less likely to develop; conversely, prolonged
hyperuricemia makes hypertension, hyperlipidemia, and hyperglycemia
more likely.
With this, we’ve basically clarified why the "Four Highs" are
intertwined—a century-old puzzle. You might feel disappointed,
wondering if solving this means returning to a primitive lifestyle.
Of course not. As long as you find the balance between your body and
environment, the problem is solved.
In the next chapter, I’ll guide you to the ultimate strategy for
managing the "Four Highs." I am Jessica. See you next time.
Key Points
1. The basis of comorbidity in the "Four Highs" is not a simple,
isolated issue but a complex, multifaceted problem.
2. The "Four Highs" lead to common outcomes through the RASS system and
insulin resistance.
3. The core issue is that the stress we face—physical and
psychological—has changed dramatically.
Comments
Post a Comment