Protein kinetics in human endotoxaemia and their temporal relation to metabolic, endocrine and proinflammatory cytokine responses

The immunomodulatory effects of social isolation in mice are linked to temperature control

Living in isolation is considered an emerging societal problem that negatively affects the physical wellbeing of its sufferers in ways that we are just starting to appreciate. This study investigates the immunomodulatory effects of social isolation in mice, utilising a two-week program of sole cage occupancy followed by the testing of immune-inflammatory resilience to bacterial sepsis. Our results revealed that mice housed in social isolation showed an increased ability to clear bacterial infection compared to control socially housed animals. These effects were associated with specific changes in whole blood gene expression profile and an increased production of classical pro-inflammatory cytokines. Interestingly, equipping socially isolated mice with artificial nests as a substitute for their natural huddling behaviour reversed the increased resistance to bacterial sepsis. Together these results suggest that the control of body temperature through social housing and huddling behaviour are important factors in the regulation of the host immune response to infection in mice and might provide another example of the many ways by which living conditions influence immunity.

Monitoring Nutrition in Critical Illness: What Can We Use?

BACKGROUND

Nutrition monitoring in the context of critical care presents unique challenges. Traditionally used anthropometric and biochemical markers may be difficult to obtain or confounded by factors such as fluid status and the inflammatory response. A previous survey identified 15 parameters in common use, all of which have confounding influences during critical illness.

MATERIALS AND METHODS

A literature search was conducted to assess current use of commonly used nutrition-monitoring parameters and to explore other possible methods that might be more useful. More than 1000 journal articles were reviewed to identify indicators of nutrition status or nutrition progress that have been used in ICU studies. The most recent 200 articles were examined to quantify the number of occurrences for each indicator. Each parameter was rated for availability and feasibility in the ICU.

RESULTS

There were 53 parameters found, including the 15 already identified as commonly used; 27 were used in ≥3 recent studies. Less-well-established nutrition indicators with potential for use in the ICU (moderate or high feasibility and availability) included ultrasound measurement of arm or leg muscle thickness, fatigue scoring with the Chalder scale, urinary creatinine assay, and serum insulin-like growth factor 1 level. None of these was among the commonly used indicators in recent studies.

CONCLUSION

This study identifies commonly used nutrition-monitoring parameters and discusses their feasibility and availability in the critical care setting. Further investigation of nutrition indicators in ICU is needed, ideally as part of a randomized trial to reduce the effect of the many possible confounding factors.

Glucagon orchestrates stress-induced hyperglycaemia

Hyperglycaemia is commonly observed on admission and during hospitalization for medical illness, traumatic injury, burn and surgical intervention. This transient hyperglycaemia is referred to as stress-induced hyperglycaemia (SIH) and frequently occurs in individuals without a history of diabetes. SIH has many of the same underlying hormonal disturbances as diabetes mellitus, specifically absolute or relative insulin deficiency and glucagon excess. SIH has the added features of elevated blood levels of catecholamines and cortisol, which are not typically present in people with diabetes who are not acutely ill. The seriousness of SIH is highlighted by its greater morbidity and mortality rates compared with those of hospitalized patients with normal glucose levels, and this increased risk is particularly high in those without pre-existing diabetes. Insulin is the treatment standard for SIH, but new therapies that reduce glucose variability and hypoglycaemia are desired. In the present review, we focus on the key role of glucagon in SIH and discuss the potential use of glucagon receptor blockers and glucagon-like peptide-1 receptor agonists in SIH to achieve target glucose control.