Abnormalities in glucose metabolism and their relevance to nutrition support in the critically ill

The association of plasma glucose, BHBA, and NEFA with postpartum uterine diseases, fertility, and milk production of Holstein dairy cows

The objective of this study was to investigate the association between the metabolic indicators such as nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), and glucose during the transition period and the development of uterine diseases. In total, 181 Holstein dairy cows were enrolled in the study. Plasma glucose, NEFA, and BHBA concentrations were measured at -50, -6, 3, 7, and 14 days relative to parturition. All cows enrolled in the study were evaluated for retained placenta (RP), metritis, and endometritis. Metritis and RP were diagnosed and treated by trained farm personnel. Clinical endometritis was evaluated by a veterinarian at 35 days in milk using a Metricheck device. We found plasma glucose concentration to be associated with the occurrence of metritis and clinical endometritis. Moreover, cows with an increased calving-to-conception interval (>150 days) presented higher plasma glucose concentrations than cows that became pregnant within the first 150 days, whereas BHBA and NEFA were not associated with the occurrence of any uterine disorder. Receiver operating characteristic (ROC) curves were used in an attempt to determine the cow-level critical thresholds for the occurrence of metritis, and endometritis. In addition, pairwise comparisons of area under the curve (AUC) of ROC curves for the critical thresholds for glucose, BHBA, and NEFA predicting the same uterine disease were performed. Glucose at 3 days in milk was the best predictor for metritis and endometritis diagnosis, with AUC values of 0.66 and 0.67, respectively. Multivariable logistic regressions were performed and showed that cows with higher levels of glucose at Day 3 were at 6.6 times higher odds of being diagnosed with metritis, and 3.5 times higher odds of developing clinical endometritis, compared with cows with lower glucose levels. Finally, a simple linear regression analysis demonstrated a negative correlation between daily milk yield in the first and second weeks of lactation and plasma glucose concentrations measured at Days 7 and 14, respectively. Concentrations of NEFA and BHBA were not found to be associated with milk production.

Cecal ligation and puncture with total parenteral nutrition: a clinically relevant model of the metabolic, hormonal, and inflammatory dysfunction associated with critical illness

BACKGROUND

Standard rat cecal ligation and puncture (CLP) results in only transient hyperglycemia, making an examination of the effects of glucoregulatory agents, such as insulin, on the morbidity and mortality of CLP problematic. Accordingly, we sought to develop a model of rat CLP with prolonged hyperglycemia through continuous infusion of total parenteral nutrition (TPN) post CLP.

MATERIALS AND METHODS

Polyethylene catheters were implanted into the femoral vein of female Sprague Dawley rats (245-265 g) which were subsequently subjected to CLP. TPN was initiated at different intervals following CLP, and mortality, bacteremia, blood glucose, hormonal, and inflammatory responses were monitored.

RESULTS

Without TPN, CLP resulted in significantly lower blood glucose at 22 h post CLP. In contrast, CLP rats receiving TPN exhibited significant prolonged hyperglycemia that was responsive to insulin treatment. Mortality and hyperglycemia tended to increase with puncture size in CLP TPN rats, with early initiation of TPN leading to poorer outcome. There were time-dependent differences in bacteremia and mortality based on time of TPN initiation. Levels of insulin, leptin, and glucagon were significantly elevated in CLP TPN rats, as were many inflammatory markers. Organ damage was evident as early as 12 h post CLP and blood cell kinetics indicated significantly depressed neutrophil and lymphocyte counts.

CONCLUSIONS

Our results indicate that addition of TPN to CLP provides a clinically relevant animal model of critical illness with associated hyperglycemia that may provide utility for the testing of glucoregulatory and other therapeutic modalities.

Influence of acute hyperglycemia in human sepsis on inflammatory cytokine and counterregulatory hormone concentrations

AIM: In human sepsis, a prominent component of the hypermetabolite is impaired glucose tolerance (IGT) and hyperglycemia. Elevations in plasma glucose concentration impair immune function by altering cytokine production from macrophages. We assessed the role of glucose in the regulation of circulating levels of insulin, glucagon, cortisol, IL-6 and TNF-α in human sepsis with normal or impaired glucose tolerance.

METHODS: According to the results of intravenous glucose tolerance test, forty patients were classified into two groups: control group (n = 20) and IGT group (n = 20). Plasma glucose levels were acutely raised in two groups and maintained at 15 mmol/L for 3 hours. Plasma insulin, glucagon and cortisol levels were measured by radioimmunoassay, the levels of TNF-α and IL-6 were detected by ELISA.

RESULTS: In IGT group, the fasting concentrations of plasma glucose, insulin, glucagon, cortisol, IL-6 and TNF-α levels were significantly higher than those in control group (P < 0.05). During clamp, the control group had a higher average amount of dextrose infusion than the IGT group (P < 0.01). In control group, plasma insulin levels rose from a basal value to a peak at an hour (P < 0.05) and maintained at high levels. Plasma glucagon levels descended from a basal value to the lowest level within an hour (P < 0.01) and low levels were maintained throughout the clamp. In IGT group, plasma insulin was more significantly elevated (P < 0.01), and plasma glucagon levels were not significantly declined. Plasma cortisol levels were not significantly changed in two groups. In control group, plasma IL-6 and TNF-α levels rose (P < 0.01) within 2 hours of the clamp and returned to basal values at 3 hours. In IGT group, increased levels of plasma cytokine lasted longer than in control group (3 hours vs. 2 hours, P < 0.05), and the cytokine peaks of IGT group were higher (P < 0.05) than those of control group.

CONCLUSION: Acute hyperglycemia pricks up hyperinsulinemia and increases circulating cytokine concentrations and these effects are more pronounced in sepsis with IGT. This suggests a potential modulation of immunoinflammatory responses in human sepsis by hyperglycemia.

Perioperative hyperglycemia, infection or risk?

This review covers the recent studies that have served to further our understanding of the nature of the relationship between perioperative hyperglycemia and nosocomial infection. On the one hand hyperglycemia can be a consequence of the systemic inflammatory response, and can serve as a marker of the severity of stress and the degree of immunocompetence resulting from infection or injury. Strong evidence is, however, emerging that hyperglycemia in the perioperative period can also be a significant risk factor for the development of nosocomial infection.