Natural Mechanisms of Adaptation to Injury
Cells regularly face resource depletion or pathogen exposure. The organism responds with multi-level reactions:
- During hypoxia (reduced energy supply), transport systems are stimulated at the systemic level: circulation and respiration are activated. At the cellular level, compensation occurs through enhanced tissue respiration and glycolysis.
- During hypoglycemia, a humoral response is triggered. The production of hormones that increase plasma glucose and its transport into tissues rises sharply: glucagon, adrenaline, glucocorticoids, and growth hormone (GH). Simultaneously, the sensitivity of cell receptors to these substances increases.
- During ischemia (reduced local blood supply), adaptation aims to increase blood flow through collateral vessels. Cells within the ischemic zone reduce their functional intensity to minimize the demand for oxygen and substrates.
Three Basic Principles of Cellular Protection
Medical interventions are divided into three main groups based on their orientation:
- Etiotropic principle. Directed strictly at the cause of the injury. The goal is to eliminate, stop, or reduce the intensity and duration of the pathogenic factor, as well as to remove conditions favoring its realization.
- Sanogenetic principle. Focuses on activating the body's intrinsic defense forces (sanogenesis). This involves stimulating mechanisms of compensation, protection, recovery, and adaptation of cells to altered conditions.
- Pathogenetic principle. Its goal is to interrupt the links in the disease development mechanism.
Main targets of pathogenetic intervention:
- Correction of energy supply.
- Protection of membranes and enzyme systems.
- Normalization of transmembrane transport and intracellular ion distribution.
- Control of cell volume.
- Protection of the genetic apparatus and correction of regulatory influences.
Correction of Energy Supply During Alteration
Since energy deficit inevitably leads to injury, therapy must restore the balance between resource delivery and consumption.
Increasing ATP delivery and synthesis:
- To ensure the transport of oxygen and substrates, $O_2$ inhalation and glucose-insulin-potassium (polarizing) solution are used.
- To facilitate transmembrane transfer into mitochondria, hyaluronidase (improves permeability) and carnitine (fatty acid carrier) are used.
- Antihypoxants are prescribed for direct stimulation of glycolysis and tissue respiration.
Reducing energy consumption: Cells are placed in conditions of "functional unloading." To reduce functional levels, sympathoadrenal system blockers, calcium channel antagonists, phosphodiesterase and protein kinase inhibitors are used. Hypothermia is also effective, globally lowering the metabolic demands of tissues.
Protection of Membranes and Enzyme Systems
The destruction of cell membranes is a critical stage of the pathological process. The protection strategy is implemented along three vectors:
- Combating free radical reactions. To reduce the formation of toxic lipid peroxidation (LPO) products, the coupling of oxidation and phosphorylation is enhanced (antihypoxants, carotenes). Free radicals are neutralized by antioxidants (tocopherols, superoxide dismutase), and already formed peroxides are destroyed by enzymes (catalase, glutathione peroxidase).
- Blockade of hydrolases. To reduce the degree of membrane alteration, calcium antagonists (preventing calcium-dependent enzyme activation) as well as phospholipase and protease inhibitors are used.
- Stabilization of lysosomal membranes. It is crucial to prevent the leakage of excess hydrolases from lysosomes into the cytoplasm, as this causes autolysis (self-digestion) of the cell. For this purpose, membrane-stabilizing drugs are used: glucocorticoids and non-steroidal anti-inflammatory drugs (NSAIDs).
Prevention and Resistance Conditioning
Preventive measures aim to prevent injury to still healthy (intact) cells. An excellent non-pharmacological method is graded conditioning of the organism: structured hypoxia, physical exertion, and cooling.
The result of such conditioning is cross-resistance. The organism increases its tolerance not only to the conditioning factor but also to entirely different agents: severe ischemia, infections, and ionizing radiation.
The pathophysiological basis of this phenomenon lies in increasing the capacity of regulatory systems, improving energy supply, activating DNA repair, accelerating protein synthesis, and forming new subcellular structures.