Microbe-Derived Butyrate and Its Receptor, Free Fatty Acid Receptor 3, But Not Free Fatty Acid Receptor 2, Mitigate Neointimal Hyperplasia Susceptibility After Arterial Injury.

Background Arterial restenosis after vascular surgery is a common cause of midterm restenosis and treatment failure. Herein, we aim to investigate the role of microbe-derived butyrate, FFAR2 (free fatty acid receptor 2), and FFAR3 (free fatty acid receptor 3) in mitigating neointimal hyperplasia development in remodeling murine arteries after injury. Methods and Results C57BL/6 mice treated with oral vancomycin before unilateral femoral wire injury to deplete gut microbiota had significantly diminished serum and stool butyrate and more neointimal hyperplasia development after arterial injury, which was reversed by concomitant butyrate supplementation. Deficiency of FFAR3 but not FFAR2, both receptors for butyrate, exacerbated neointimal hyperplasia development after injury. FFAR3 deficiency was also associated with delayed recovery of the endothelial layer in vivo. FFAR3 gene expression was observed in multiple peripheral arteries, and expression was increased after arterial injury. Treatment of endothelial but not vascular smooth muscle cells with the pharmacologic FFAR3 agonist 1-methylcyclopropane carboxylate stimulated cellular migration and proliferation in scratch assays. Conclusions Our results support a protective role for butyrate and FFAR3 in the development of neointimal hyperplasia after arterial injury and delineate activation of the butyrate-FFAR3 pathway as a valuable strategy for the prevention and treatment of neointimal hyperplasia.

Vascular Injuries in Intravenous Drug Addicts-A Single-Center Experience.

BACKGROUND: Infected false aneurysms (IFA) caused by intravenous drug abuse are uncommon but challenging lesions. The best approach for the surgical management of this condition is still unknown. The aim is to present a single-center 14-year experience in the IFA treatment in intravenous drug abusers, thus providing additional data regarding the treatment options and outcome in these patients. METHODS: A retrospective analysis of 32 consecutive patients with vascular injuries secondary to intravenous drug abuse, during the period from January 2004 to April 2018, was performed. Data of interest were extracted from patients' medical history records, anesthesia charts, and database implemented in daily practice, or were obtained by personal contact. The diagnosis was set based on history, physical examination and/or color Doppler sonography, multidetector computed tomographic angiography, and digital subtraction angiography. The outcome included graft patency, limb amputation, and mortality. RESULTS: During study period, 32 heroin abusers, predominantly males (81%), were surgically treated due to vascular injuries, with mean age of 35.2 years. The vast majority of patients have had an injury of the lower extremity blood vessels (84.3%) and the common femoral artery was the most common site of injury (59.4%). Three-quarters of patients underwent resection of the false aneurysm and ligation of the artery without reconstruction of the blood vessel. In 7 cases (21.9%), arterial reconstruction was performed with overall failure rate of 42.86%. The overall mortality rate was 6.25% and the rate of extremity salvage was 96.7%. CONCLUSIONS: The best treatment option is yet to be found, but based on the results of the present study, ligation of affected artery without revascularization seems to be an efficient, safe, and optimal treatment method, with minor risk of the extremity loss.

Human Pythiosis: Emergence of Fungal-Like Organism.

Pythiosis is an emerging infectious disease caused by the aquatic oomycete Pythium insidiosum, a fungal-like organism. It is believed that P. insidiosum's zoospores, its infected form, play major role in pathogenesis. Vascular and ocular infections are the most common clinical manifestation in humans. It is difficult to establish the diagnosis given its relatively rarity and difficulty to distinguish P. insidiosum from other molds. Delay in diagnosis and treatment has been associated with poor outcomes. High index of suspicion is the key, particularly in thalassemia patients with arterial insufficiency and patients with fungal keratitis/endophthalmitis without improvement on antifungal therapy. Tissue culture and zoospore induction remain gold standard for diagnosis; however, DNA-based method should be performed simultaneously. The combination of radical surgery, antifungal agents, and immunotherapy has been recommended. It was previously believed that surgery with negative surgical margins was the essential to survive in vascular pythiosis; however, it was recently found that patients could have residual disease despite documented negative surgical margins as infected clot may be dislodged to proximal arterial sites prior to surgery. Serum ß-D-glucan (BG) has been used to monitor disease response after treatment initiation in vascular pythiosis. A significant decrease in BG levels within 2 weeks after surgery is indicative of the absence of residual infection. Unfortunately, monitoring tools for ocular pythiosis are not yet available. Itraconazole plus terbinafine have generally been used in P. insidiosum-infected patients; however, antibacterial agents, including azithromycin and linezolid, have also been used with favorable outcomes in ocular disease. Recently, azithromycin or clarithromycin plus doxycyclin were used in two relapsed vascular pythiosis patients with good outcomes.

[A Case of Delayed Vascular Injury as a Complication Related to Implanted Central Venous Port Catheter].

A 74-year-old woman with advanced gastric cancer was admitted to our hospital. A central venous (CV) port catheter was implanted into the right subclavian vein for preoperative chemotherapy and parenteral nutritional management. On the 35th day after implantation, she complained of diarrhea, fever and dyspnea. The chest radiograph showed a right-sided massive pleural effusion. As the patient progressively fell into severe respiratory distress, endotracheal intubation was performed for management of respiration by mechanical ventilation. Initially, given the patient's symptoms, she was diagnosed with septic shock. Therefore, after placement of a CV catheter through the right femoral vein, in consideration of the possibility of a port infection, she was treated with thoracentesis and infusion of antibiotics. The patient gradually recovered, and again received parenteral nutrition through the CV port catheter. After the infusion was administered, she complained of dyspnea. A CT scan of the chest revealed a right pleural effusion and displacement of the tip of the CV port catheter out of the wall of the superior vena cava. We diagnosed delayed vascular injury (DVI), and the CV port catheter was removed. She soon recovered with conservative treatment. We speculated that the initial respiratory symptoms such as the pleural effusion were caused by DVI. DVI should therefore be recognized as a complication related to implanted CV port catheters.

Porphyromonas gingivalis promotes neointimal formation after arterial injury through toll-like receptor 2 signaling.

We previously demonstrated that Porphyromonas gingivalis infection induces neointimal hyperplasia with an increase in monocyte chemoattractant protein (MCP)-1 after arterial injury in wild-type mice. Toll-like receptor (TLR) 2 is a key receptor for the virulence factors of P. gingivalis. The aim of this study was to assess whether TLR2 plays a role in periodontopathic bacteria-induced neointimal formation after an arterial injury. Wild-type and TLR2-deficient mice were used in this study. The femoral arteries were injured, and P. gingivalis or vehicle was injected subcutaneously once per week. Fourteen days after arterial injury, the murine femoral arteries were obtained for histopathologic and immunohistochemical analyses. The immunoglobulin-G levels of the P. gingivalis-infected groups were significantly increased in comparison with the level in the corresponding noninfected groups in both wild-type and TLR2-deficient mice. TLR2 deficiency negated the P. gingivalis-induced neointimal formation in comparison with the wild-type mice, and reduced the number of positive monocyte chemoattractant protein-1 cells in the neointimal area. These findings demonstrate that P. gingivalis infection can promote neointimal formation after an arterial injury through TLR2 signaling.