Empagliflozin Inhibits Basal and IL-1ß-Mediated MCP-1/CCL2 and Endothelin-1 Expression in Human Proximal Tubular Cells.

SGLT2 inhibitors (SGLT2i) slow the progression of chronic kidney disease; however, evidence for the underlying molecular mechanisms is scarce. We investigated SGLT2i-mediated effects on differential gene expression in two independent human proximal tubular cell (HPTC) lines (HK-2 and RPTEC/TERT1) at the mRNA and protein levels under normoglycemic conditions, utilizing IL-1ß as a pro-inflammatory mediator. Microarray hybridization identified 259 genes that were uniformly upregulated by IL-1ß (10 mg/mL) and downregulated by empagliflozin (Empa) (500 nM) after 24 h of stimulation in two independent HPTC lines (n = 2, each). The functional annotation of these genes identified eight pathway clusters. Among 12 genes annotated to the highest ranked cluster (enrichment score, 3.51), monocyte chemoattractant protein-1/CC-chemokine ligand 2 (MCP-1/CCL2) and endothelin-1 (ET-1) were selected for verification at mRNA and protein levels based on their established involvement in the early pathogenesis of chronic kidney disease: IL-1ß upregulated basal MCP-1/CCL2 (15- and 19-fold) and ET-1 (3- and 8-fold) mRNA expression, while Empa downregulated basal MCP-1/CCL2 (0.6- and 0.5-fold) and ET-1 (0.3- and 0.2-fold) mRNA expression as early as 1 h after stimulation and for at least 24 h in HK-2 and RPTEC/TERT1 cells, respectively. The co-administration of Empa inhibited IL-1ß-mediated MCP-1/CCL2 (0.2-fold, each) and ET-1 (0.2-fold, each) mRNA expression as early as 1 h after ligand stimulation and for at least 24 h in both HPTC lines, respectively. This inhibitory effect of Empa on basal and IL-1ß-mediated MCP-1/CCL2 and ET-1 mRNA expression was corroborated at the protein level. Our study presents novel evidence for the interference of SGLT2 inhibition with tubular inflammatory response mechanisms under normoglycemic conditions that might account for SGLT2i-mediated nephroprotection.

Intradialytic Calcium Kinetics and Cardiovascular Disease in Chronic Hemodialysis Patients.

BACKGROUND/OBJECTIVE: Calcium loading has been associated with cardiovascular risk in hemodialysis (HD) patients. However, it remains to be elucidated whether alterations of intradialytic calcium buffering add to the increased cardiovascular disease burden in this high-risk population. METHODS: Intradialytic calcium kinetics was evaluated in a cross-sectional observational study by measuring dialysate-sided ionized calcium mass balance (iCaMB), calcium buffer capacity, and change in serum calcium levels in 40 chronic HD patients during a routine HD session. A dialysate calcium of 3.5 mEq/L was used to adequately challenge calcium buffer mechanisms. Aortic pulse wave velocity and serum osteocalcin levels were measured prior to the HD session. Presence of cardiovascular disease and diabetes was assessed. RESULTS: The mean dialysate-sided iCaMB, extracellular fluid ionized calcium mass gain, and buffered ionized calcium mass were 469 (±154), 111 (±49), and 358 (±145) mg/HD, respectively. The mean ionized serum calcium increase (∆iCa) was 0.42 (±0.14) mEq/L per HD. The mean intradialytic calcium buffer capacity was 73 (±18)%. Multivariate regression analysis revealed significant independent association of (1) iCaMB with the dialysate-to-blood calcium gradient at HD start and (2) intradialytic calcium buffer capacity with undercarboxylated osteocalcin. The presence of coronary heart disease was associated with higher ∆iCa but not iCaMB in the multivariate model. CONCLUSIONS: In line with our proof-of-concept study, we provide clinical evidence for a rapidly accessible and exchangeable calcium pool involved in intradialytic calcium regulation and for the role of osteocalcin as a potential biomarker. Our findings argue for evaluating the prognostic potential of intradialytic calcium kinetics in prospective clinical trials.

Infectious Tenosynovitis of the Tibialis Anterior Due to Mycobacterium chelonae After Intravenous Heroin Injection.

Mycobacterium chelonae is a ubiquitous Gram-positive, acid-fast, non-spore-forming bacterium commonly encountered in nature associated with aquatic animals, soil, and water, including tap water. Nontuberculous mycobacterial tenosynovitis infections caused by M. chelonae in the lower extremity are uncommon, leading to a paucity of literature documenting the diagnosis and treatment of such cases. This report is of a 65-year-old male patient who was found to have an M. chelonae infection along the tibialis anterior tendon after injecting himself with heroin into the dorsal foot veins. This review covers the diagnosis and treatment as well as a case report on the outcome of infectious tenosynovitis of the tibialis anterior associated with M. chelonae. To date, this is the only reported case of tibialis anterior infectious tenosynovitis caused by M. chelonae after intravenous heroin injection.

Unraveling reno-protective effects of SGLT2 inhibition in human proximal tubular cells.

Large clinical trials demonstrated that SGLT2 inhibitors (SGLT2i) slow the progression of kidney function decline in type 2 diabetes. Because the underlying molecular mechanisms are largely unknown, we studied the effects of SGLT2i on gene expression in two human proximal tubular (PT) cell lines under normoglycemic conditions, utilizing two SGLT2i, namely empagliflocin and canagliflocin. Genome-wide expression analysis did not reveal substantial differences between these two SGLT2i. Microarray hybridization analysis identified 94 genes that were both upregulated by TGF-ß1 and downregulated by either of the two SGLT2i in HK-2 and RPTEC/TERT1 (renal proximal tubular epithelial cells/telomerase reverse transcriptase 1) cells. Extracellular matrix organization showed the highest significance in pathway enrichment analysis. Differential gene expression of three annotated genes of interest within this pathway was verified on mRNA level in both cell lines. Whereas TGF-ß1 induced mRNA expression of thrombospondin 1 (THBS1; 4.3-fold), tenascin C (TNC; 8-fold), and platelet-derived growth factor subunit B (PDGF-B; 4.2-fold), SGLT2i downregulated basal mRNA expression of THBS1 (0.2-fold), TNC (0.5 fold), and PDGF-B (0.6-fold). Administration of SGLT2i in the presence of TGF-ß1 resulted in a significant inhibition of TGF-ß1-induced THBS1 and TNC mRNA expression and TGF-ß1-induced THBS1, TNC, and PDGF-BB protein expression. We conclude that SGLT2i block basal and TGF-ß1-induced expression of key mediators of renal fibrosis and kidney disease progression in two independent human PT cell lines.

Extraskeletal Chondroma with Concomitant Arthrosis of the Foot at the First Metatarsophalangeal Joint A Case Report.

Extraskeletal chondroma is a benign tumor that is found most often in the fingers but can be found in the feet as well. A symptom of this lesion is pressure from the slow-growing mass. We present the case of a 58-year-old woman who presented with an extraskeletal chondroma in the plantar aspect of the left first metatarsophalangeal joint with concomitant symptomatic arthrosis at the joint. Operative treatment was excision of the lesion in addition to arthrodesis of the joint attributable to the presence of symptomatic arthrosis. The patient was seen approximately 1 year postoperatively and had no postoperative complications. Distinction between extraskeletal chondromas and other lesions, such as extraskeletal myxoid chondrosarcomas, is critical because delayed treatment of the latter has the propensity to lead to detriment to the patient. Therefore, proper diagnosis is critical.

The PhytoClust tool for metabolic gene clusters discovery in plant genomes.

The existence of Metabolic Gene Clusters (MGCs) in plant genomes has recently raised increased interest. Thus far, MGCs were commonly identified for pathways of specialized metabolism, mostly those associated with terpene type products. For efficient identification of novel MGCs, computational approaches are essential. Here, we present PhytoClust; a tool for the detection of candidate MGCs in plant genomes. The algorithm employs a collection of enzyme families related to plant specialized metabolism, translated into hidden Markov models, to mine given genome sequences for physically co-localized metabolic enzymes. Our tool accurately identifies previously characterized plant MGCs. An exhaustive search of 31 plant genomes detected 1232 and 5531 putative gene cluster types and candidates, respectively. Clustering analysis of putative MGCs types by species reflected plant taxonomy. Furthermore, enrichment analysis revealed taxa- and species-specific enrichment of certain enzyme families in MGCs. When operating through our web-interface, PhytoClust users can mine a genome either based on a list of known cluster types or by defining new cluster rules. Moreover, for selected plant species, the output can be complemented by co-expression analysis. Altogether, we envisage PhytoClust to enhance novel MGCs discovery which will in turn impact the exploration of plant metabolism.