Inflamação Crônica [ Patologia Geral ]

Summary

This video explains chronic inflammation, its causes, and its cellular mechanisms. Chronic inflammation is a prolonged response that may involve tissue damage, repair attempts, and varying degrees of inflammation. Key causes include persistent infections, hypersensitivity diseases, and prolonged exposure to harmful agents like cigarette smoke. The process is marked by mononuclear cell infiltration, tissue destruction, and collagen deposition during repair. Macrophages and lymphocytes play crucial roles, with macrophages activating T-cells and promoting tissue repair or fibrosis. The video also discusses granulomatous inflammation and how it helps contain difficult-to-eliminate pathogens, such as tuberculosis, through the formation of granulomas.

Takeaways

• 😀 Chronic inflammation is a prolonged response lasting from weeks to months, where tissue injury, inflammation, and repair attempts coexist.
• 😀 Causes of chronic inflammation include persistent infections from hard-to-eliminate pathogens, hypersensitivity diseases, and prolonged exposure to harmful agents (e.g., cigarette smoke).
• 😀 Chronic inflammation is characterized by a mononuclear cell infiltrate, including macrophages, lymphocytes, and plasma cells, as well as significant tissue destruction and repair through fibrosis.
• 😀 Angiogenesis, the formation of new blood vessels, is crucial in chronic inflammation as it supports the influx of inflammatory cells and helps in tissue repair.
• 😀 Macrophages are the key cells in chronic inflammation, acting in phagocytosis and tissue repair through cytokine production and activation of other immune cells like T lymphocytes.
• 😀 Macrophages can be activated in two ways: M1 (classically activated) by microbial agents and interferon-gamma, which promotes inflammation, and M2 (alternatively activated), which is involved in tissue repair and fibrosis.
• 😀 T lymphocytes, specifically Th1, Th2, and Th17 subsets, play distinct roles in chronic inflammation, producing various cytokines that activate other immune cells and direct the immune response.
• 😀 B lymphocytes also contribute to chronic inflammation by producing antibodies that can target foreign antigens or self-antigens, often leading to autoimmune diseases.
• 😀 Eosinophils participate in chronic inflammation, particularly in allergic reactions, by releasing toxic proteins during degranulation, which can cause tissue damage.
• 😀 Granulomatous inflammation occurs in response to persistent pathogens and involves the formation of granulomas, a structure composed of activated macrophages, multinucleated giant cells, and lymphocytes to contain hard-to-eliminate pathogens like tuberculosis bacteria.

Q & A

What is chronic inflammation?

Chronic inflammation is a prolonged immune response that lasts for weeks to months, characterized by the coexistence of tissue injury, inflammation, and repair attempts. The severity of each component can vary during this prolonged process.

What are the main causes of chronic inflammation?

The primary causes of chronic inflammation include persistent infections (such as tuberculosis), hypersensitivity diseases, and prolonged exposure to harmful agents like cigarette smoke.

What morphological features are characteristic of chronic inflammation?

Chronic inflammation is marked by an infiltration of mononuclear cells (macrophages, lymphocytes, plasmocytes), extensive tissue destruction, and tissue repair, primarily through the deposition of collagen. This process is facilitated by angiogenesis, which provides nutrients to inflamed tissues.

How do macrophages function in chronic inflammation?

Macrophages are key players in chronic inflammation. They help eliminate microorganisms and dead tissue, produce cytokines that promote tissue repair, and activate other immune cells like T lymphocytes. Macrophages also differentiate into two forms: M1 (pro-inflammatory) and M2 (anti-inflammatory and repair-focused).

What is the role of M1 and M2 macrophages in chronic inflammation?

M1 macrophages are classically activated and produce pro-inflammatory cytokines to combat infections, while M2 macrophages, activated through interleukin-4, assist in tissue repair and suppress inflammation later in the process, promoting fibrosis and healing.

How do T-cells contribute to chronic inflammation?

T-cells, particularly Th1, Th2, and Th17 subsets, play a central role in chronic inflammation. Th1 cells activate M1 macrophages and produce interferon-gamma, while Th2 cells recruit eosinophils through interleukins. Th17 cells recruit neutrophils through interleukins and cytokines, contributing to inflammation.

What is the role of B-cells in chronic inflammation?

B-cells contribute to chronic inflammation by producing antibodies, which can target both foreign antigens and the body's own tissues, especially in autoimmune diseases. These antibodies can play a role in sustaining the inflammatory response.

How do eosinophils participate in chronic inflammation?

Eosinophils play a significant role in chronic inflammation, especially in allergic reactions and parasitic infections. They release toxic proteins from their granules during degranulation, which can damage tissues and help eliminate pathogens.

What is granulomatous inflammation, and when does it occur?

Granulomatous inflammation occurs when the immune system forms a granuloma to contain a persistent pathogen that is difficult to eliminate. It is commonly seen in infections like tuberculosis, where the granuloma isolates the microorganism, often leading to fibrosis over time.

What are the two types of granulomas and how do they differ?

There are two types of granulomas: foreign body granulomas, which form around inert substances like silica or talc, and immune granulomas, which form in response to difficult-to-eliminate microorganisms, such as those causing tuberculosis. Foreign body granulomas are primarily for isolating non-reactive substances, while immune granulomas aim to contain infectious agents.