Functional metabolomics reveal the role of AHR/GPR35 mediated kynurenic acid gradient sensing in chemotherapy-induced intestinal damage

Intestinal toxicity induced by chemotherapeutics has become an important reason for the interruption of therapy and withdrawal of approved agents. In this study, we demonstrated that chemotherapeutics-induced intestinal damage were commonly characterized by the sharp upregulation of tryptophan (Trp)−kynurenine (KYN)−kynurenic acid (KA) axis metabolism. Mechanistically, chemotherapy-induced intestinal damage triggered the formation of an interleukin-6 (IL-6)−indoleamine 2,3-dioxygenase 1 (IDO1)−aryl hydrocarbon receptor (AHR) positive feedback loop, which accelerated kynurenine pathway metabolism in gut. Besides, AHR and G protein-coupled receptor 35 (GPR35) negative feedback regulates intestinal damage and inflammation to maintain intestinal integrity and homeostasis through gradually sensing kynurenic acid level in gut and macrophage, respectively. Moreover, based on virtual screening and biological verification, vardenafil and linagliptin as GPR35 and AHR agonists respectively were discovered from 2388 approved drugs. Importantly, the results that vardenafil and linagliptin significantly alleviated chemotherapy-induced intestinal toxicity in vivo suggests that chemotherapeutics combined with the two could be a promising therapeutic strategy for cancer patients in clinic. This work highlights GPR35 and AHR as the guardian of kynurenine pathway metabolism and core component of defense responses against intestinal damage.

Clonal Hematopoiesis: A New Step Linking Inflammation to Heart Failure

Heart failure is a common disease with poor prognosis that is associated with cardiac immune cell infiltration and dysregulated cytokine expression. Recently, the clonal expansion of hematopoietic cells with acquired (i.e., nonheritable) DNA mutations, a process referred to as clonal hematopoiesis, has been reported to be associated with cardiovascular diseases including heart failure. Mechanistic studies have shown that leukocytes that harbor these somatic mutations display altered inflammatory characteristics that worsen the phenotypes associated with heart failure in experimental models. In this review, we summarize recent epidemiological and experimental evidence that support the hypothesis that clonal hematopoiesis-mediated immune cell dysfunction contributes to heart failure and cardiovascular disease in general.

Mesenteric venous thrombosis

Mesenteric vein thrombosis is increasingly recognized as a cause of mesenteric ischemia. Acute thrombosis commonly presents with abdominal pain and chronic type with features of portal hypertension. Contrast enhanced CT scan of abdomen is quite accurate for diagnosing and differentiating two types of mesenteric venous thrombosis. Prothrombotic state, hematological malignancy, and local abdominal inflammatory conditions are common predisposing conditions. Over the last decade, JAK-2 (janus kinase 2) mutation has emerged as an accurate biomarker for diagnosis of myeloproliferative neoplasm, an important cause for mesenteric venous thrombosis. Anticoagulation is the treatment of choice for acute mesenteric venous thrombosis. Thrombolysis using systemic or transcatheter route is another option. Patients with peritoneal signs or refractory to initial measures require surgical exploration. Increasing recognition of mesenteric venous thrombosis and use of anticoagulation for treatment has resulted in reduction in the need for surgery with improvement in survival.