Incidence of perioperative hypotension in patients undergoing transurethral resection of bladder tumor after oral 5-aminolevulinic acid administration: a retrospective multicenter cohort study.

PURPOSE: Tumors can be visualized using 5-Aminolevulinic acid hydrochloride (5-ALA) during transurethral resection of bladder tumors (TURBT). Hypotension is an adverse effect of 5-ALA; however, its incidence and morbidity rates are unknown. This study aimed to describe the incidence of perioperative hypotension and identify risk factors for hypotension among patients after 5-ALA administration in TURBT. METHODS: This retrospective multicenter cohort study was conducted at three general hospitals in Japan. Adult patients who underwent elective TURBT after 5-ALA administration between April 2018 and August 2020 were included. The primary outcome was the incidence of perioperative hypotension (mean blood pressure < 65 mmHg). The secondary outcomes were the use of vasoactive agents and adverse events, including urgent intensive care unit (ICU) admission. Multivariate logistic regression analysis was performed to investigate risk factors of the incidence of intraoperative hypotension. RESULTS: The median age of 261 patients was 73 years. General anesthesia was induced in 252 patients. The intraoperative hypotension was observed in 246 (94.3%) patients. Three patients (1.1%) were urgently admitted to the ICU for continued vasoactive agent use after surgery. All three patients had renal dysfunction. Multivariate logistic regression analysis revealed that general anesthesia was significantly associated with intraoperative hypotension (adjusted odds ratio, 17.94; 95% confidence interval, 3.21-100.81). CONCLUSION: The incidence of hypotension in patients undergoing TURBT after 5-ALA administration was 94.3%. The incidence of urgent ICU admission with prolonged hypotension was 1.1% in all patients with renal dysfunction. General anesthesia was significantly associated with intraoperative hypotension.

The chloroplastic 2-oxoglutarate/malate transporter has dual function as the malate valve and in carbon/nitrogen metabolism.

Transport of dicarboxylates across the chloroplast envelope plays an important role in transferring carbon skeletons to the nitrogen assimilation pathway and exporting reducing equivalent to the cytosol to prevent photo-inhibition (the malate valve). It was previously shown that the Arabidopsis plastidic 2-oxoglutarate/malate transporter (AtpOMT1) and the general dicarboxylate transporter (AtpDCT1) play crucial roles at the interface between carbon and nitrogen metabolism. However, based on the in vitro transport properties of the recombinant transporters, it was hypothesized that AtpOMT1 might play a dual role, also functioning as an oxaloacetate/malate transporter, which is a crucial but currently unidentified component of the chloroplast malate valve. Here, we test this hypothesis using Arabidopsis T-DNA insertional mutants of AtpOMT1. Transport studies revealed a dramatically reduced rate of oxaloacetate uptake into chloroplasts isolated from the knockout plant. CO(2) -dependent O(2) evolution assays showed that cytosolic oxaloacetate is efficiently transported into chloroplasts mainly by AtpOMT1, and supported the absence of additional oxaloacetate transporters. These findings strongly indicate that the high-affinity oxaloacetate transporter in Arabidopsis chloroplasts is AtpOMT1. Further, the knockout plants showed enhanced photo-inhibition under high light due to greater accumulation of reducing equivalents in the stroma, indicating malfunction of the malate valve in the knockout plants. The knockout mutant showed a phenotype consistent with reductions in 2-oxoglutarate transport, glutamine synthetase/glutamate synthase activity, subsequent amino acid biosynthesis and photorespiration. Our results demonstrate that AtpOMT1 acts bi-functionally as an oxaloacetate/malate transporter in the malate valve and as a 2-oxoglutarate/malate transporter mediating carbon/nitrogen metabolism.