Currently, the terms low-grade inflammation and chronic subclinical inflammation are frequently used, but these terms are synonymous (hereinafter referred to collectively as low-grade inflammation). What is the concept of low-grade inflammation? The definition of inflammation in Basic Pathology, published in 2003, is the cellular damage caused by exogenous and endogenous agonists in living tissues with a vascular system and the resulting complex response of the body’s cells and tissues.
This emphasizes the vascular response as a central part of the inflammatory process. Chronic inflammation is the simultaneous presence of active inflammation, tissue damage and repair processes lasting from weeks to months or even years, distinguished from acute inflammation by vascular changes, edema and massive neutrophil infiltration. It may occur after acute inflammation or may be latent and gradual, starting without acute inflammatory manifestations or with a mild response.
In our opinion, low-grade inflammation mainly refers to the chronic course of this inflammation, the clinical manifestations of typical inflammation of redness, swelling, heat and pain, the low titers of inflammatory indicators (previously considered to be in the normal range), and the subclinical pathological state that was previously ignored and thought to be normal before the corresponding morphological changes were induced.
Low-grade inflammation is a key cause of the development and progression of atherosclerosis (AS) and a major pathogenic factor in metabolic syndromes (type 2 diabetes, obesity, essential hypertension, dyslipidemia, etc.), and the view that As and type 2 diabetes are inflammatory diseases is basically widely accepted. These understandings are the major advances in the cardiovascular field in recent years; it is now believed that AS is an inflammatory disease, and it is not cholesterolemia that plays an important role in the formation of AS, and anti-inflammatory therapy has an anti-AS effect. Anti-inflammatory therapy has now become a new tool in the treatment of AS and diabetic complications.
Hypo-inflammation belongs to the category of Western pathology, which is a pathological state. What about the TCM pathology of hypo-inflammation? Only by facing the new viewpoints emerging from the development of modern medicine and interpreting it with the thinking of Chinese medicine can we better utilize the advantages of Chinese medicine and make our Chinese medicine persistent.
Modern Chinese medicine considers phlegm and blood stasis as the main pathological products of low-grade inflammation, and phlegm and blood stasis as the basic disease characteristics of low-grade inflammation. In recent years, there have been more studies on the material basis of phlegm, and the material basis of phlegm that are more uniformly recognized and widely accepted are: (1) elevated blood cholesterol, triglycerides and low-density lipoprotein; (2) elevated blood glucose is the essence of phlegm evidence in diabetes mellitus; (3) immunoglobulins IgG and IgM, complement components C3 and C4, and total complement CH50 are significantly elevated, which may be the cause of some immune diseases including the material basis of the sputum of inflammation; (4) free radicals. From the low degree of inflammatory process, we can see that LDL, the free radicals that lead to the oxidation and modification of LDL, and the multiple immune products of the inflammatory process, lipid deposition and fibrofatty lesions are the specific manifestation of phlegm pathology.
In recent decades, many scholars have devoted themselves to the study of TCM symptoms and microscopic indicators, and found that blood stasis is closely related to the pathological changes of thrombosis, connective tissue proliferation and degeneration, disorders of the coagulation and fibrinolytic systems, and dysregulation of immune function, as described in modern medicine. During the process of low-level inflammation, the aggregation of various organic components in and outside the blood vessels, such as platelet adhesion, aggregation and thrombosis, transformation of monocytes into foam cells, followed by subendothelial deposition, connective tissue formation, fibrous plaques, smooth muscle cell proliferation and immune dysfunction are all specific manifestations of blood stasis in Chinese medicine.
From the clinical manifestations, a series of clinical manifestations appear in the late stage of low-grade inflammation, such as thickening, tortuosity and hardening of superficial arteries (temporal artery, radial artery, brachial artery, etc.); vertigo, headache, loss of consciousness, limb paralysis, and distorted eyes and mouth in cerebral atherosclerosis; palpitation, chest tightness, and pain in the precordial area in coronary atherosclerosis; coldness, numbness, and intermittent claudication in lower limbs in limb atherosclerosis The symptoms of mesenteric artery atherosclerosis include abdominal pain. These clinical symptoms are identified by Chinese medicine as phlegm and blood stasis.
Phlegm for the disease, varied, as Wang Yinjun said: “phlegm for things, with the Qi lift, nowhere, for wheezing for cough, for vomiting for diarrhea, for dizziness and heartburn, for palpitations, for cold and heat, swelling and pain, for plumpness and fullness of compartment, …… seemingly sneaky non-sneaky, are all phlegm evidence.” Sometimes although there is no substantial phlegm and drink visible, but can also be determined according to the symptoms and signs caused by the pathological changes of phlegm and drink. For example, phlegm drink in the meridians, manifested as limb numbness, hemiplegia, crooked mouth and eyes; phlegm drink in the heart, manifested as chest tightness, palpitations, dizziness, epilepsy. It can be seen that the clinical manifestations of organ involvement caused by low degree inflammation are very similar to the discussion of invisible phlegm in Chinese medicine.
Due to blood stagnation, pain is one of the main symptoms of blood stasis, and the pain is needle-like and fixed, long-term and stubborn. Tang Rongchuan’s “Theory of Blood Evidence” says: “When blood stasis is between the internal organs and meridians, it causes pain around the body.” “When blood stasis is in the middle jiao, there is abdominal pain and hypochondriac pain.” Whether it is headache in the late stage of low degree inflammation that occurs in cerebral atherosclerosis, intermittent claudication in extremity atherosclerosis, pain in the precordial region in coronary atherosclerosis, or abdominal pain in mesenteric artery atherosclerosis, all have pain as the main symptom, which is the specific manifestation of stasis of blood. The pulse signs of stasis of blood include string pulse, astringent pulse and knotted pulse. The thickening, tortuous and hardening of superficial arteries in the late stage of low-grade inflammation are the typical signs of string pulse in Chinese medicine. In addition, low-grade inflammation occurs insidiously and is difficult to heal for a long time, which is in line with the theory of “prolonged illness will lead to stasis” in Chinese medicine.