Intravascular granulocyte aggregates caused by the selectin-binding carbohydrate fucoidin in pig kidneys

The effect of fucoidin on kidney and lung injury in a rat infrarenal aortic ischemia-reperfusion model

BACKGROUND

The aim of this study was to investigate the effects of fucoidin on rat kidney and lung in an infraaortic ishemia reperfusion model.

METHODS

Forty Wistar rats were randomly divided into five groups (n = 8) as sham, control (IR), before ischemia (BI), before reperfusion (BR), and before ischemia and before reperfusion (BI/BR). Rats were subjected to 120 minutes ischemia followed by 120 minutes reperfusion with application of infrarenal aortic clamping. BI received intravenous fucoidin (25 mg/kg) ten minutes before establishing ischemia and BR received ten minutes before reperfusion. BI/BR group received half equal doses of fucoidin both before ischemia (12.5 mg/kg) and reperfusion (12.5 mg/kg) periods, respectively. After sacrification blood and tissue samples were obtained for biochemical (Malondialdehyde (MDA), Nitric oxide (NO), Myeloperoxidase (MPO), Catalase (CAT), Plasma Chitotriosidase (CHIT) and serum ischemia modified albumin (IMA)) and histologic examinations.

RESULTS

MDA, NO, MPO, CAT, and IMA levels were lower in BR and BI/BR groups compared to control group (p < 0.001). Plasma CHIT levels in BR and BI/BR groups were lower than in control group (p < 0.05). According to histological examination kidney and lung injury scores were lower in BR and BI/BR groups compared to control group (p < 0.01 and p < 0.001, respectively).

CONCLUSION

The study showed that fucoidin is effective in preventing kidney and lung injury if administered before reperfusion or both before ischemia and reperfusion. However, it has no effect if administered only before ischemia.

Isolation and culture of fibroblasts, vascular smooth muscle, and endothelial cells from the fetal rat ductus arteriosus

The ductus arteriosus (DA), a fetal arterial shunt vessel between the proximal descending aorta and the pulmonary artery, closes shortly after birth. Initial functional closure as a result of the DA's smooth muscle contraction is followed by definite anatomical closure. The latter involves several complex mechanisms like endothelial cushion formation and smooth muscle cell migration resulting in fibrosis and sealing of the vessel. These complex steps indicate highly specialized functions of the DA vascular smooth muscle cells (VSMCs), endothelial cells, and fibroblasts. Herein, we describe a new reproducible method for isolating VSMCs, endothelial cells, and fibroblasts of high viability from fetal rat DA using immunomagnetic cell sorting. Purity of the different cell cultures was assessed by immunohistochemistry and flow cytometry and ranged between 85 and 94%. The capability of the VSMCs to react to hypoxic stimuli was assessed by intracellular calcium and ATP measurements and by VEGF mRNA expression analysis. VSMCs respond to hypoxia with decreases in intracellular calcium concentrations and ATP levels, whereas VEGF mRNA expression increased 3.2-fold. The purified vessel-specific different cell types are suitable for subsequent gene expression profiling and functional studies and provide important tools for improving our understanding of the complex processes involved in the closure of the DA.

Fucoidin, an inhibitor of leukocyte adhesion, exacerbates acute ischemic renal failure and stimulates nitric oxide synthesis

OBJECTIVES

To lessen renal ischemic injury caused by fucoidin, a substance capable of reducing tissue infiltration by neutrophils, and to seek a possible interrelationship with the nitric oxide system which may also modulate leukocyte infiltration.

MATERIAL AND METHODS

Acute ischemic renal failure was induced in rats by uninephrectomy followed by 60 min of clamping of the renal artery. The rats were injected with fucoidin (25 mg/kg) or fucoidin+nitroprusside (2.5 mg/kg) before reperfusion, and urine was collected for 24 h afterwards. Serum and urine were examined for creatinine sodium and protein; creatinine clearance and fractional excretion of sodium (FENa) were calculated. The renal tissue of the sacrificed animals was examined histologically for tissue damage and histochemically for myeloperoxidase, a marker of neutrophil infiltration. The nitric oxide system was evaluated by measuring urinary nitrates and inducible nitric oxide synthase messenger RNA (iNOs mRNA).

RESULTS

Renal failure was more severe in the fucoidin group than the nitroprusside group (creatinine clearance 0.11+/-0.08 ml/min for ischemia+fucoidin versus 0.26+/-0.11 ml/min for ischemia only; p<0.002). Adding nitroprusside to fucoidin lessened the decline in creatinine clearance (0.13+/-0.13 ml/min; p=NS). Fucoidin was associated with greater tubular damage, as evidenced by increased FENa (7.2%+/-2.8% vs 1.51%+/-1.96% for ischemia only; p<0.001). Nitroprusside weakened this trend. Fucoidin caused an increase in the fractional excretion of nitrates, a response accompanied by increased iNOS mRNA.

CONCLUSIONS

Fucoidin failed to protect the kidney from ischemic damage and was even nephrotoxic. It also stimulated the formation of iNOS RNA.

Influence of Cold Storage on Renal Ischemia Reperfusion Injury after Non-Heart-Beating Donor Explantation

BACKGROUND

Due to the increasing need for kidney donors, transplantation from non-heart-beating donors (NHBD) is currently being practiced more extensively. As detailed studies on the reperfusion injury of these kidneys do not exist so far, a comparison of renal ischemia reperfusion injury scores immediately after organ explantation with injury scores after NHBD organ explantation with subsequent cold storage would be useful.

METHODS

Non-stored kidneys were compared to a group of kidneys stored for 6.9 +/- 1.8 h. Functional analyses were made during 145 min of ex vivo perfusion. Quantitative histological analyses were performed in all kidneys after termination of perfusion.

RESULTS

During ex vivo reperfusion, renal vascular resistance was elevated, while creatinine clearance, filtration fraction, renal oxygen consumption, and sodium reabsorption were below normal after non-heart-beating explantation and further decreased after subsequent washing and cold storage. In the kidneys subjected to cold preservation, histologically tubular damage was enhanced, and the total count, as well that for the intraglomerular neutrophil granulocytes were also elevated.

CONCLUSIONS

Explantation from NHBD causes renal ischemia reperfusion injury. Cold storage augmented deterioration of the kidney as histologically and functionally demonstrated. Thus, preservation times for non-heart-beating kidneys should be carefully reappraised.