Repair of metabolic processes

The role of the mitochondrion in trauma and shock

The mitochondrion of the eukaryotic cell is well known as a "power plant" whose energy is made available via the high-energy phosphate bonds of ATP. This indispensable and superbly adapted organelle appears to have originated as an endosymbiotic bacterium rather than as a eukaryotic creation per se. However, under the dangerous conditions of trauma and shock, the mitochondrion can become destabilized and harm its host cell in a variety of ways. These contrary traits may be, in part, vestiges from the bacterial origins of mitochondria. The mitochondrion can respond to the stress of trauma and shock by opening pores that leak contents into the host cell's cytoplasm, an event that can trigger programmed cell death or necrosis. In addition, the enormous oxygen consumption by mitochondria presents a two-edged sword in that a deranged mitochondrion can produce reactive oxygen species that damage genes and gene products, inflicting considerable harm to the mitochondrion and its host cell. However, although trauma and shock can cause the mitochondrion to wreak havoc in many ways, an adjuvant intervention with exogenous ATP-MgCl2 after trauma and shock appears useful for reducing cell and organ damage under those conditions.

Stress and stress disorders during and after intensive care

PURPOSE OF REVIEW

We provide an overview of the multilevel/multidimensional approach to stress and stress disorders, and integrate research findings into the intensive care context. Recent findings are discussed within the context of well studied biopsychological theories of stress and stress disorders.

RECENT FINDINGS

The stress response must be viewed as a process. It should be discussed in terms of perception, immediate response and prolonged manifestations. There are correlations with biological principles, in that neurotransmitters can be distinguished on the basis of speed of response, duration of action and range of activity. Nevertheless, discussions on vulnerability to stress and the ability to cope with stressors are important. Findings regarding the influence of chronic stress and dysfunction of the hypothalamo-pituitary axis on stress disorders after intensive care encourage us to consider preoperative interventions that reduce chronic stress and therefore re-establish proper function of the hypothalamo-pituitary axis.

SUMMARY

Stress disorders can be viewed as a consequence either of the action of humoral substances or of failure to recover. Studies on the process of psychophysiological recovery in the intensive care unit are urgently needed. Patient factors such as type of illness, age and sex should be considered modifiers of the stress response. In addition, the interaction between molecular mechanisms of the tissue healing process and the psychophysiological stress response require more intensive study.