Oral-bacterial-induced arterial and venous thrombus in rats: Pathological and immunological studies

Buerger Disease: Pathological Changes in Elderly Patients

Reports of vascular lesion changes in elderly Buerger disease patients are rare. Patients are expected to continue to have typical Buerger disease even after the age of 50. However, after 50, when patients suffer from atherosclerotic risk factors, such as hypertension, diabetes mellitus, or hyperlipidemia, what kind of changes will occur? We will report on 3 cases of hypertension, diabetes mellitus, or hyper lipidemia after or around 50 years of age. As a result, atherosclerosis was present in the iliac or aortic regions in the remaining thromboangiitis lesions below the groin area. (This is secondary publication from the J Jpn Coll Angiol 2021; 61: 107–113.)

The IL-33/sST2 Axis in Thromboangiitis Obliterans

Background

Until recently, it remains unknown whether thromboangiitis obliterans (TAO) is a type of systemic vasculitis. A high level of IL-33 and its soluble decoy receptor sST2 in the acute phase of systemic vasculitis has been demonstrated.

Methods

The serum level of IL-33 and sST2 in 50 TAO patients, 20 age- and smoking habit-matched controls and 19 age-matched non-smoker controls was evaluated.

Results

The mean level of IL-33 in TAO, smokers and non-smokers was 370.2±61.7ng/mL,132.14±2.6ng/mL and 11.3±0.38ng/mL, respectively. The IL-33 was significantly higher in the TAO than in either control groups (p < 0.001). The IL-33 in the acute phase of TAO was significantly higher than in the patients in the quiescent phase of the disease (p = 0.019). Also, IL-33 in the patients with gangrene was significantly higher than in the patients with non-healing ulcers (p = 0.021). The sST2 in the TAO patients was 49.3±5.58ng/mL, and in smoker and non-smoker controls, it was 45.3±6.3ng/mL and 4.11±0.17ng/mL, respectively. No significant difference was found between the patients and smoker control groups (p = 0.87). The mean ratio of IL-33/sST2 was 27.89±10.44 in the TAO group and, in smokers and non-smokers, it was 2.85±0.48 and 2.84±0.14, respectively. A significantly high level of IL-33/sST2 ratio was observed in TAO patients in both the active and quiescent phases of the disease in comparison to both control groups (p<0.001).

Conclusion

The regulation pattern of IL-33/sST2 was different in TAO in comparison to autoimmune vasculitis.

Oral-bacterial-induced arterial and venous thrombus in rats: Pathological and immunological studies

Objectives

Our study investigated the pathological outcome of experimental thrombi that incorporate oral bacteria.

Material and methods

A small artery and vein in the rats' groins were injected with a solution containing periodontal bacteria Porphyromonas gingivalis and followed up for 28 days. In all, 18 limbs of nine male rats (500-650 g) were used for the arterial study, and eight limbs of four rats were used for the veins. Two densities of the bacterial solution and two arterial thicknesses sizes were used in the arterial study. Both proximal and distal arteries and veins were ligated loosely using a monofilament nylon suture before bacterial suspensions or control solutions were injected into the ligated vessels.

Results

After 7, 14-18, and 28 days, the rats were sacrificed. Pathology and immunohistochemistry were performed. All specimens exhibited thrombus formation and an acute inflammation reaction with granulocytes at 7 days and then settled down to chronic fibrous change with plasma cells or macrophages at 28 days in the arterial thrombus. CD3 (Pan T-cells), CD79a (Pan B cells in the rats), and IgG were observed in the process of the healing of the arterial thrombus. Venous changes showed relatively clear recanalization that appeared at 7 days, which is slightly different from the artery. Granulocytes were present from 7 to 28 days.

Conclusions

Periodontal bacteria act as an inflammatory core in the vessels, but not as an infectious agent, in our experiments, because of their low ability to invade tissues.