Cardiopulmonary bypass increases coronary IL-8 in diabetic patients without evidence of reperfusion injury

Mesenteric endothelial dysfunction in a cardiopulmonary bypass rat model: the effect of diabetes

BACKGROUND

Diabetes is a risk factor for perioperative complications after cardiac surgery. We studied its effects on mesenteric endothelial function in a cardiopulmonary bypass (CPB) model.

METHODS

Forty Wistar rats were divided into four groups: sham (D-CPB-), cardiopulmonary bypass (D-CPB+), diabetic (D+CPB-) and diabetic that have undergone CPB (D+CPB+). Two samples of mesenteric artery were used for nitric oxide synthase (NOS) Western blot analysis, and two others for assessing contractile response and endothelium relaxations. Nitrite products and tumour necrosis factor-alpha (TNF-α) were assessed as markers of inflammatory response.

RESULTS

We observed an enhanced contractile response to the α-adrenergic agonist associated with impairment of mesenteric vasorelaxation in D+CPB+ rats. Western immunoblot analysis of D+CPB+ highlighted an additive effect of hyper-expression of inducible NOS. A significantly increased inflammatory response was observed after CPB in diabetic animals.

CONCLUSIONS

This work confirms the potential deleterious impact of diabetes on the mesenteric endothelium during CPB in cardiac surgery.

Impact of Endothelial Activation on Infective and Inflammatory Complications after Cardiac Surgery in type II Diabetes Mellitus

Purpose

Altered endothelial response has been described in diabetics after cardiac surgery. Infections and inflammatory organ damage often complicate the postoperative course. We evaluated endothelial/cytokine response (ECR) after cardiac surgery and its role on infective/inflammatory complications of type II diabetic patients.

Methods

Perioperative ECR of 60 diabetic patients (Group A) undergoing cardiopulmonary bypass was compared to that of 60 non-diabetics (Group B). Hemodynamics, endothelial markers [vascular endothelial growth factor (VEGF) and monocyte chemotactic protein-1 (MCP-1)], pro-inflammatory (IL-2, IL-6, IL-8) and anti-inflammatory cytokines (IL-10) were analyzed preoperatively (T0), at time of aortic declamping (T1), at ITU admission (T2), at 12 h (T3) and 24 h (T4) postoperatively. Postoperative infective/inflammatory complications were registered, and the related ECR was analyzed.

Results

Hemodynamics were comparable. No differences were found in perioperative IL-6 (p=0.776) and IL-8 (p=0.660) between the 2 groups. However, the diabetics showed significantly higher endothelial activation (VEGF p=0.0001, p=0.0001 since T1 to T3; MCP-1 p=0.0001, p<0.007 at T1, T3 and T4) with lower IL-10 (p=0.0001, p<0.05 at T2, T3, T4) and lower IL-2 secretion (p=0.0001, p<0.0001 at T1, T2). Infections developed in 23.3% of the diabetics; inflammatory complications in 13.3%. Those developing infections showed significantly lower IL-2 (p=0.042; p ≤. 021 at T1 and T2) than patients without infections, whereas those with complicated inflammatory lung or renal injury had higher MCP-1 leakage (p=0.006) with lower IL-10 (p=0.005).

Conclusions

The diabetics showed higher endothelial activation and lower antiinflammatory response to CPB compared to non-diabetics. Infections in diabetic patients correlated with depressed IL-2, while inflammatory complications correlated to higher endothelial activation and lower anti-inflammatory cytokine secretion.

Hind Limb Ischemia-Reperfusion in the Leptin Receptor Deficient (db/db) Mouse

BACKGROUND

Diabetic patients have high incidence of peripheral vascular disease and limb loss after acute extremity injury. Experiments were designed to test the hypothesis that acute tissue injury in leptin receptor deficient (Db) diabetic (type2) mice would be more severe than in non-diabetic mice.

METHODS

Db and wild type (Wt) mice were subjected to 3 h of ischemia followed by either 4 or 24 h of reperfusion (3/4 IR, 3/24 IR). Muscle analyzed for tissue viability (mitochondrial activity), cytokines (KC-murine equivalent of human IL-8, TNFalpha, IL-6), growth factor, and histological evaluation (neutrophils/uninjured muscle fibers). Tissue perfusion was detected during basal and reperfusion conditions using laser Doppler imaging.

RESULTS

Mitochondrial activity and histological evaluation for tissue injury did not differ in the Db versus Wt mice at the time intervals studied. When compared with their respective sham animals, both Db and Wt mice had similarly increased levels of KC, IL-6, and VEGF after 3/24 IR. TNFalpha levels increased in Db but not Wt mice after IR. Although absolute increases in TNFalpha and KC were higher in Db mice, VEGF levels were actually lower in the Db mice.

CONCLUSION

The patterns of tissue perfusion, cytokines, and growth factors were different in Db versus Wt mice. At the acute time intervals studied, these differences did not correlate with an expected greater degree of acute muscle injury in Db mice.

Differences in gene expression profiles of diabetic and nondiabetic patients undergoing cardiopulmonary bypass and cardioplegic arrest

BACKGROUND

Diabetes mellitus is an independent risk factor for early postoperative mortality and complications after coronary artery bypass grafting (CABG). We sought to compare the cardiac gene expression responses to cardiopulmonary bypass (CPB) and cardioplegic arrest (C) in patients with and without diabetes.

METHODS AND RESULTS

Twenty atrial myocardium samples were harvested from 5 type II insulin-dependent diabetic and 5 matched nondiabetic patients undergoing CABG, before and after CPB/C. Oligonucleotide microarray analyses of 12625 genes were performed on the 10 sample pairs using matched pre-CPB tissues as controls. Array results were validated with Northern blotting and immunoblotting. Compared with pre-CPB/C, post-CPB/C myocardial tissues revealed 851 upregulated and 480 downregulated genes with a threshold P< or =0.025 (signal-to-noise ratio, 4.04) in the diabetic group, compared with 480 upregulated and 626 downregulated genes (signal-to-noise ratio, 3.04) in the nondiabetic group (P<0.001). There were 18 genes that were upregulated >4-fold in diabetic and nondiabetic patients (including inflammatory/transcription activators FOS, CYR 61, and IL-6, apoptotic gene NR4A1, stress gene DUSP1, and glucose-transporter gene SLC2A3). However, 28 genes showed such marked upregulation in the diabetic group exclusively (including inflammatory/transcription activators MYC, IL8, IL-1beta, growth factor vascular endothelial growth factor, amphiregulin, and glucose metabolism-involved gene insulin receptor substrate 1), and 27 genes in the nondiabetic group only, including glycogen-binding subunit PPP1R3C.

CONCLUSIONS

Gene expression profile after CPB/C is quantitatively and qualitatively different in patients with diabetes. These results have important implications for the design of tailored myocardial protection and operative strategies for diabetic patients undergoing CPB/C.

A long-term stable normothermic cardiopulmonary bypass model in neonatal swine

BACKGROUND

An appropriate animal model of cardiopulmonary bypass (CPB) is critical in order to study the morbidity and mortality in newborn children undergoing long-term cardiac surgery. Since this has been reported to be technically difficult, this paper describes a neonatal porcine CPB model (3 days old, n = 18) for up to 8 h to study long-term bypass.

METHODS

After anesthesia, neonates had arterial/venous monitoring lines inserted, they were heparinized (300 IU/kg), the aorta was cannulated for arterial retroperfusion, and a two-stage venous drainage catheter was placed in the right atrium. A Medtronic Minimax Plus oxygenator and the bypass circuit were primed with donor blood and CPB was instituted.

RESULTS

Line and mean arterial pressures were kept at 147.7 +/- 73 and 62.7 +/- 9 mm Hg, respectively. Myocardial (38.1 +/- 1.0 degrees C) and rectal temperatures (37.7 +/- 1.0 degrees C) were maintained. Heart rate was 184.8 +/- 34.5 bpm. Hematocrits were 29.6 +/- 6.0%, activated clotting time was sustained above 400 s throughout bypass, blood gas parameters were maintained in the normal range (pH, 7.39 +/- 0.1; PO(2), 123.1 +/- 65.2 mm Hg; PCO(2), 37.2 +/- 8.5 mm Hg; and HCO(3)(-), 21.5 +/- 3.6 mmol/L). CPB was terminated after 8 h and no visceral edema or other imbalances normally associated with swine on bypass were observed.

CONCLUSIONS

Results demonstrate a model of stable long-term bypass in neonatal swine which can be used to study issues critical to children requiring surgical correction and CPB at a young age. Overall effects of surgery and bypass on these younger patients have yet to be explored and therefore a stable long-term normothermic model of CPB would allow the study of numerous parameters associated with this complicated procedure.

IL-8 concentration in coronary sinus blood during early coronary reperfusion after ischemic arrest

OBJECTIVE

Activation of the inflammatory response is an important factor contributing to complications of cardiopulmonary bypass. Increased level of proinflammatory cytokine - IL-8 has been reported during coronary artery bypass grafting (CABG) operations with the use of cardiopulmonary bypass. The aim of this study was to find out whether the heart is the main source of IL-8 during early coronary reperfusion.

METHODS

IL-8 concentration in coronary sinus before clamping and 5, 10, and 15 min after declamping of the aorta as well as in radial artery blood before clamping and 10 min after declamping of the aorta, was assessed in 30 patients undergoing CABG surgery.

RESULTS

We observed increase in IL-8 concentration in coronary sinus blood after declamping of the aorta, however no difference between coronary sinus and arterial blood concentration was noted. The median value of IL-8 concentration in coronary sinus blood was 1.85 pg/ml before ischemia and 15.4, 20.3, and 29.3 pg/ml in 5, 10 and 15 min after aortic declamping, respectively. Our additional finding was that there was a negative correlation between IL-8 level and hemoglobin saturation with oxygen in coronary sinus blood 10 min after coronary reperfusion.

CONCLUSIONS

We conclude that the heart is not the main source of IL-8 in early coronary reperfusion, although coronary reperfusion induces its release.