Multiple electrolytes imbalances in a patient with inflammatory bowel disease associated with vitamin D deficiency: a case report

BACKGROUND

Inflammatory bowel disease involves chronic inflammation and ulceration, primarily Crohn's disease and ulcerative colitis. The prevalence of inflammatory bowel disease is rising in industrialized countries. We describe the case of a patient with inflammatory bowel disease and multiple electrolyte disturbances that emphasize the link between a vitamin D deficiency and electrolyte imbalances.

CASE

An 86-year-old Japanese man with severe hypocalcemia, hypophosphatemia, hypokalemia, and hypomagnesemia was referred to the gastroenterology and hepatology department our university hospital for severe diarrhea and abdominal pain. Based on clinical symptoms and biochemical and endoscopic findings, Crohn's disease, intestinal Behçet's disease, and intestinal tuberculosis were considered as differential diagnoses, but a final diagnosis was not reached. Prednisolone, azathioprine, and metronidazole were administered, and no apparent electrolyte abnormality was observed at the patient's admission to our hospital. On the 80th hospital day, marked hypocalcemia, hypophosphatemia, hypokalemia, and hypomagnesemia were noted and prolonged, despite daily supplementation with Ca and inorganic P. At his consultation with our department, we observed decreased fractional excretion of Ca, tubular reabsorption of phosphate, fractional excretion of K, and fractional excretion of Mg, suggesting the depletion of vitamin D and extrarenal wasting of K and Mg. The patient's serum Ca and inorganic P were quickly elevated in response to treatment with an active form of vitamin D, and his serum levels of K and Mg were restored to the normal range by an intravenous administration of K and Mg. A vitamin D deficiency is not rare in inflammatory bowel disease and is caused primarily by the decreased intestinal absorption of vitamin D. In the management of electrolyte imbalances in patients with inflammatory bowel disease, clinicians must consider the possible development of vitamin D deficiency-related disorders.

CONCLUSION

Vitamin D deficiency in entero-Behçet's disease leads to severe hypocalcemia and hypophosphatemia, highlighting the importance of awareness in management.

Relationship between office blood pressure and actual antihypertensive drug use in patients with hypertension following the promulgation of the guidelines for hypertension (JSH2019)

To achieve appropriate blood pressure control in the treatment of hypertension in Japan, this study examined the relationship between office blood pressure and actual antihypertensive drug use in general hospitals following the promulgation of the guidelines for hypertension (JSH2019). This study focused on blood pressure levels and drug use in outpatients on antihypertensive treatment from June to July 2020. The subjects were 2,537 patients classified into four groups based on their medical history, patients with: hypertension only; hypertension and cardiovascular disease; hypertension and dyslipidaemia; and hypertension and diabetes mellitus. The results showed a significant difference in systolic blood pressure (SBP) between patients with hypertension only and those with hypertension and cardiovascular disease (138.3±17.9 mmHg vs 135.6±19.9 mmHg, p<0.05). Regarding actual drug use, it was found that diuretics were prescribed more frequently in patients with hypertension and cardiovascular disease than in those with hypertension alone (15.5% vs 37.9%, p<0.05), even though the number of drugs for hypertension did not differ significantly. In addition, the dose of diuretics was greater only in patients with cardiovascular disease. These results show the actual drug use and blood pressure for each comorbidity. Furthermore, they suggest that the results of antihypertensive treatment may differ by changing the combination and dosage of antihypertensive drugs without changing the number of antihypertensive drugs used. The study also shows the problem of using less diuretics depending on the risk the patient has, and solving the problem may lead to achieving further antihypertensive goals.

Measurements of neutrino oscillation parameters from the T2K experiment using 3.6×1021 protons on target

The T2K experiment presents new measurements of neutrino oscillation parameters using 19.7 ( 16.3 ) × 10 20 protons on target (POT) in (anti-)neutrino mode at the far detector (FD). Compared to the previous analysis, an additional 4.7 × 10 20 POT neutrino data was collected at the FD. Significant improvements were made to the analysis methodology, with the near-detector analysis introducing new selections and using more than double the data. Additionally, this is the first T2K oscillation analysis to use NA61/SHINE data on a replica of the T2K target to tune the neutrino flux model, and the neutrino interaction model was improved to include new nuclear effects and calculations. Frequentist and Bayesian analyses are presented, including results on sin 2 θ 13 and the impact of priors on the δ CP measurement. Both analyses prefer the normal mass ordering and upper octant of sin 2 θ 23 with a nearly maximally CP-violating phase. Assuming the normal ordering and using the constraint on sin 2 θ 13 from reactors, sin 2 θ 23 = 0 . 561 - 0.032 + 0.021 using Feldman-Cousins corrected intervals, and Δ m 32 2 = 2 . 494 - 0.058 + 0.041 × 10 - 3 eV 2 using constant Δ χ 2 intervals. The CP-violating phase is constrained to δ CP = - 1 . 97 - 0.70 + 0.97 using Feldman-Cousins corrected intervals, and δ CP = 0 , π is excluded at more than 90% confidence level. A Jarlskog invariant of zero is excluded at more than 2 σ credible level using a flat prior in δ CP , and just below 2 σ using a flat prior in sin δ CP . When the external constraint on sin 2 θ 13 is removed, sin 2 θ 13 = 28 . 0 - 6.5 + 2.8 × 10 - 3 , in agreement with measurements from reactor experiments. These results are consistent with previous T2K analyses.

IN.PACT AV access randomized trial: Japan cohort outcomes through 12 months

PURPOSE

There is a lack of adjudicated and prospectively randomized published outcomes on the use of drug-coated balloons (DCB) to treat dysfunctional arteriovenous fistula in Asian patients. This post hoc subgroup analysis of 112 Japanese participants from the global IN.PACT AV Access trial reports outcomes through 12 months.

MATERIALS AND METHODS

Participants were treated with DCB (n = 58) or standard non-coated percutaneous transluminal angioplasty (PTA) balloons (n = 54). Outcomes included target lesion primary patency (TLPP), access circuit primary patency, and safety.

RESULTS

Through 6 months, TLPP was 86.0% (49/57) in the DCB group and 49.1% (26/53) in the PTA group (p < 0.001). Through 12 months, TLPP was 67.3% (37/55) in the DCB group and 43.4% (23/53) in the PTA group (p = 0.013).

CONCLUSION

In this post hoc analysis of Japanese participants from the IN.PACT AV Access trial, participants treated with DCB had higher TLPP through 6 and 12 months compared with PTA.

Nuclear accumulation of MLKL induces necroptosis in cardiomyocytes: potential implication in Doxorubicin-induced cardiotoxicity

Background

The treatment with doxorubicin, a powerful chemotherapeutic agent, has been shown to be associated with an increased risk of lethal heart failure. Although various types of cell death pathway such as apoptosis and ferroptosis have been shown to be involved in the development of doxorubicin-induced cardiotoxicity, DIC, the involvement of necroptosis, a novel programmed necrosis induced by translocation of activated mixed lineage kinase domain-like protein, MLKL, to plasma membrane, remains unclear.

Purpose

The aim of this study was to determine whether necroptosis is involved in the development of DIC.

Methods and results

DIC was induced in C57BL/6J mice by intraperitoneal injection of doxorubicin at a dose of 10 mg/kg 3 times for a week. Eight days after the commencement of injection, echocardiographic analyses showed that left ventricular ejection fraction assessed by echocardiography was significantly lower in the doxorubicin-treated mice than in the vehicle-treated mice (44.0±13.7 vs. 70.5±3.7%), indicating the development of DIC. Immunoblot analysis showed that MLKL protein level was higher by 1.6 fold in the doxorubicin-treated mice than in the vehicle-treated mice. Interestingly, immunohistochemical analysis showed that signals of phospho-Ser345-MLKL, an activated form of MLKL, was found in the nuclei in addition to cytosol and intercalated discs of cardiomyocytes in the doxorubicin-treated mice. To get novel insight into significance of nuclear MLKL accumulation, a leucine-rich nuclear export signal (NES) spanning amino acids 280–284 of rat MLKL was identified by site-directed mutation analyses, and H9c2 cells, cultured rat cardiomyoblasts, were transfected with expression constructs for nucleus-directed MLKL (FLAG-mtNES-MLKL) or its wild type (FLAG-WT-MLKL). Percentage of FLAG-positive cells stained with Zombie Red, a fluorescent dye that is non-permeant to live cells, was higher in FLAG-mtNES-MLKL-transfected cells than in FLAG-WT-MLKL-transfected cells (80.0±3.5% vs. 6.3±1.3%, p&lt;0.05), whereas percentage of cells immunostained with cleaved caspase-3 to FLAG-positive cells was similar in the two groups. The effect of the MLKL mutant on necroptosis was attenuated by treatment with GppNHp, an inhibitor of Ran-mediated nuclear protein import.

Conclusion

Nuclear accumulation of MLKL induces necroptosis in cardiomyocytes, which may contribute to progression of DIC.

Funding Acknowledgement

Type of funding sources: None.

Assessment of an Automatic Hot Water Sterilizing System-Equipped Dialysis Supply Device's Circuit Degradation, 7 Years Postinstallment

At most dialysis clinics in Japan, a central dialysis fluid delivery system (CDDS) is used primarily to provide consistent treatment to patients. We incorporated hot water disinfection to a CDDS over a 7 year period, after which we assessed the dialysis purification levels. We observed that adequate levels had been maintained. We rated the internal circuits of the device at the 7 year mark, comparing the insides of both the used and unused new Synflex tubing, silicone blades, Teflon tubing, silicone rubber tubing, and stainless steel parts. No bacteria or contamination (such as endotoxins) was detected, and no degradation or damage were observed. Even after the auto-hot water disinfection system was installed, no internal tubing degradation due to hot water or mechanical issues have occurred, and the system's dialysis fluid purification levels have been maintained.

Changes in practice patterns in Japan from before to after JSDT 2013 guidelines on hemodialysis prescriptions: results from the JDOPPS

BACKGROUND

The Japanese Society for Dialysis Therapy (JSDT) published in 2013 inaugural hemodialysis (HD) guidelines. Specific targets include 1.4 for single-pool Kt/V (spKt/V) with a minimum dose of 1.2, minimum dialysis session length of 4 hours, minimum blood flow rate (BFR) of 200 mL/min, fluid removal rate no more than 15 mL/kg/hr, and hemodiafiltration (HDF) therapy for certain identified symptoms. We evaluated the effect of these guidelines on actual practice in the years spanning 2005 - 2018.

METHODS

Analyses were carried out to describe trends in the above HD prescription practices from December 2005 to April 2013 (before guideline publication) to August 2018 based on prevalent patient cross-sections from approximately 60 randomly selected HD facilities participating in the Japan Dialysis Outcomes and Practice Patterns Study.

RESULTS

From April 2006 to August 2017 continual rises occurred in mean spKt/V (from 1.35 to 1.49), and percent of patients having spKt/V>1.2 (71% to 85%). Mean BFR increased with time from 198.3 mL/min (April 2006) to 218.4 mL/min (August 2017) , along with percent of patients with BFR >200 ml/min (65% to 85%). HDF use increased slightly from 6% (April 2006 and August 2009) to 8% by April 2013, but increased greatly thereafter to 23% by August 2017. In contrast, mean HD treatment time showed little change from 2006-2017, whereas mean UFR declined from 11.3 in 2006 to 8.4 mL/Kg/hour in 2017.

CONCLUSIONS

From 2006 - 2018 Japanese HD patients experienced marked improvement in reaching the spKt/V target specified by the 2013 JSDT guidelines. This may have been due to moderate increase in mean BFR even though mean HD session length did not change much. In addition, HDF use increased dramatically in this time period. Other HD delivery changes during this time, such as increased use of super high flux dialyzers, also merit study. While we cannot definitively conclude a causal relationship between the publication of the guidelines and the subsequent practice changes in Japan, those changes moved practice closer to the recommendations of the guidelines.

Intracellular localization of AMP deaminase and its novel role in BCAA and lipid metabolism in diabetic cardiomyopathy

Background

A metabolomic study in the human heart suggested a pivotal role of amino acid (AA) metabolism in fatty acid oxidation, which is dysregulated in type 2 diabetes mellitus (T2DM) and heart failure. We previously reported that aberrant up-regulation of AMP deaminase 3 (AMPD3) impairs cardiac energetics in T2DM hearts, and AMPD3 was recently shown to be activated by fasting and to promote AA metabolism and fatty acid oxidation in skeletal muscle. A sodium glucose cotransporter 2 inhibitor (SGLT2i) has been shown to augment systemic AA metabolism, but its effect on cardiac AA metabolism remains unknown.

Purpose

We hypothesized that AMPD3 has a role in AA and lipid metabolism in cardiomyocytes and that the protective effect of an SGLT2i in diabetic hearts is mediated by modification of AA and lipid metabolism.

Methods and results

Proteomic analyses of AMPD3 immunoprecipitates in rat hearts revealed that AMPD3 interacted with the E1α and E2 components of the BCKDH complex, a rate-limiting enzyme of branched-chain AA (BCAA) catabolism. Immunoblotting using subcellular fractions revealed that BCKDH localized not only in the mitochondria matrix but also in the cytosol and endoplasmic reticulum (ER) and that AMPD3 interacted with BCKDH in the cytosol and ER. Despite comparable expression of BCKDH components and phosphorylation of E1α at Ser293, significant accumulation of BCAA was observed in T2DM rats (OLETF; 317±30 nmol/g) compared to that in control rats (LETO; 213±16 nmol/g), and the accumulation of BCAA was accompanied by up-regulation of AMPD3 in the cytosol and ER by 98% and 231%, respectively. In cardiomyocytes, disruption of BCAA catabolism by knockdown of BCKDH-E1α resulted in a 5.8-fold increase in AMPD3 at the transcriptional level and blunted lipid droplet biogenesis in response to a long-chain fatty acid challenge. Next, myocardial infarction (MI) was induced in LETO and OLETF pretreated with empagliflozin (10 mg/kg/day, 14 days) or a vehicle. Pathway analysis of cardiac metabolites revealed arginine biosynthesis and BCAA metabolism as the most significantly changed pathways with empagliflozin, with BCAA (791±187 nmol/g), glutamate, glutamine and urea being significantly increased. Empagliflozin restored myocardial ATP and survival after MI in OLETF to levels comparable to those in LETO. Electron microscopy showed a significantly higher prevalence of myocardium lipid droplets in OLETF, which was further increased by empagliflozin.

Conclusions

The results support the hypotheses that imbalance of extra-mitochondrial AMPD3-BCKDH interaction underlies dysregulated BCAA metabolism in T2DM hearts and that activation of cardiac AA metabolism by an SGLT2i normalizes fatty acid overload through sequestration into intracellular lipid droplets.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Boehringer Ingelheim

Antibacterial and Osteoinductive Implant Surface Using Layer-by-Layer Assembly

Osseointegration of dental, craniofacial, and orthopedic implants is critical for their long-term success. Multifunctional surface treatment of implants was found to significantly improve cell adhesion and induce osteogenic differentiation of dental-derived stem cells in vitro. Moreover, local and sustained release of antibiotics via nanolayers from the surface of implants can present unparalleled therapeutic benefits in implant dentistry. Here, we present a layer-by-layer surface treatment of titanium implants capable of incorporating BMP-2-mimicking short peptides and gentamicin to improve their osseointegration and antibacterial features. Additionally, instead of conventional surface treatments, we employed polydopamine coating before layer-by-layer assembly to initiate the formation of the nanolayers on rough titanium surfaces. Cytocompatibility analysis demonstrated that modifying the titanium implant surface with layer-by-layer assembly did not have adverse effects on cellular viability. The implemented nanoscale coating provided sustained release of osteoinductive peptides with an antibacterial drug. The surface-functionalized implants showed successful osteogenic differentiation of periodontal ligament stem cells and antimicrobial activity in vitro and increased osseointegration in a rodent animal model 4 wk postsurgery as compared with untreated implants. Altogether, our in vitro and in vivo studies suggest that this approach can be extended to other dental and orthopedic implants since this surface functionalization showed improved osseointegration and an enhanced success rate.

P–017 The maintenance of testicular architecture and germ cell in adult testis tissue under organ culture condition based on the gas-liquid interface method

Study question

Can the gas-liquid interface organ culture system that achieved in vitro spermatogenesis in mice also support in vitro spermatogenesis in human adult testis?

Summary answer

Although the progression of spermatogenesis was not observed, germ cells were maintained without the degeneration of the architecture in both fresh and cryopreserved testicular tissues.

What is known already

Although the research on in vitro spermatogenesis have been conducted for 100 years, only the organ culture system using gas-liquid interface method achieved in vitro spermatogenesis in mice. It has not been verified whether this culture system can be applied to other mammals including humans and induce spermatogenesis.

Study design, size, duration

Testicular tissue was obtained from the transgender patients receiving sex reassignment surgery. Testicular specimens were either immediately processed for cultivation or cryopreserved, using a vitrification freezing protocol. Organ culture of testicular fragments was performed in three different media for a maximum period of 3 weeks to evaluate the short-term changes in the cultured tissues (viability, proliferation and maintenance of germ and somatic cells).

Participants/materials, setting, methods

Fresh and cryopreserved-thawed testis fragments (1–2 mm3) were cultured using the organ culture system in alpha-MEM with knock-out serum replacement (K group), alpha-MEM with lipid-rich BSA (A group) and DMEM with FBS (D group). Luteinizing hormone, follicle stimulating hormone and testosterone were supplemented. The number of germ cells (using DDX4), proliferative activity of germ cells (using EdU assay) and intratubular cell apoptosis (by TdT-mediated dUTP Nick End Labeling) were evaluated by immunohistochemical staining weekly.

Main results and the role of chance

The architecture of the seminiferous tubules was maintained until the second week of culture in both the fresh and the cryopreserved culture group. The number of DDX4-positive germ cells per seminiferous tubule in groups D, K, and A was 49 ± 24, 55 ± 21, 50 ± 26 cells/tubule in 1 day, 32 ± 13, 42 ± 7, 36 ± 21 cells/tubule in 1week, respectively. The numbers gradually decreased to 26 ± 8, 24 ± 6 and 27 ± 18 cells/tubule, in 2 weeks, respectively, with no difference among the groups. The number of intratubular EdU-positive cells of groups D, K, and A was 0.2 ± 0.2, 2.8 ± 2.1, 1.1 ± 0.8 cells/tubule at 1 day, 0.1 ± 0.2, 0.5 ± 0.6, 0.3 ± 0.6 cells/tubule at 1 week, respectively. The values were 0.01, 0.05, and 0.03 at 2 weeks. Thus, EdU-positive cells drastically decreased from the first week of culture. The number of DDX4-positive germ cells and the intratubular EdU-positive cells in the cryopreserved culture group was not different from that in the fresh culture group.

Limitations, reasons for caution

Current organ culture systems are incomplete, being unable to induce human in vitro spermatogenesis. Further research is needed to improve culture condition with the aim of producing fertile sperm of infertile adult male patients.

Wider implications of the findings: Our organ culture system could maintain testis structure and germ cells. By using the testis tissues of the transgender patients, which are available with their consent, we will promote the investigation of the culture condition necessary for germ cell proliferation and differentiation.

Trial registration number

Grant-in-Aid for Scientific Research on Innovative Areas 18H05546, Grant-in-Aid for Young Scientists (A) 17H05098 and Takeda Science Foundation

Annual dialysis data report of the 2018 JSDT Renal Data Registry: dementia, performance status, and exercise habits

According to the annual survey of the Japanese Society for Dialysis Therapy Renal Data Registry (JRDR) conducted at the end of 2018, there were a total of 339,841 patients receiving dialysis (hereinafter, dialysis patients) in Japan. The survey included questions regarding the presence/absence of dementia, the performance status (PS), and the exercise habits of individual patients. The survey revealed that 10.8% of all dialysis patients had dementia (1.8% in the age group of less than 65 years, 6.8% in the age group of 65–74 years, and 22.7% in the age group of 75 years or older). These prevalences of dementia were approximately equal to those estimated from the survey conducted in 2010. Regarding PS, the percentage of patients with lower activity levels tended to be relatively high among patients who were less than 15 years old and those who were 60 years old or older. Concerning the exercise habits of dialysis patients, the percentage of patients who were classified as “not at all or hardly” in response to the question about exercise habit was the highest (60–80%) of all the exercise habit classifications in each of the age groups analyzed.

Radiation doses of workers engaged in decontamination of the environment

After the accident at Fukushima Daiichi nuclear power plant on 11 March 2011, radioactive materials were released into the atmosphere resulting in environmental contamination. Following the implementation of environmental decontamination efforts, the Radiation Dose Registration Centre of the Radiation Effects Association established the radiation dose registration system for decontamination and related workers to consolidate and prevent the loss of radiation records. This article presents statistics on the radiation doses of decontamination and related workers using official records. Since approximately 10 years have passed since the accident in Fukushima, the types of work conducted in the affected restricted areas have changed over time. Therefore, changes in radiation dose for each type of work and comparisons with nuclear workers are presented.

Novel adsorptive type apheresis device Immunopure for ulcerative colitis from clinical perspectives based on clinical trials: Japan and Europe

Several adsorptive type devices for ulcerative colitis are used for the induction of remission in patients with active severe disease worldwide. In 2020, the novel apheresis device Immunopure for ulcerative colitis was launched in Japan. Immunopure, like the polyethylene terephthalate column, uses polyarylate, a type of polyester resin, as the adsorbent. Similar to the cellulose acetate column, Immunopure is filled with adsorbent beads and expected to provide ease of use, with minimal risk of column clogging. Immunopure adsorbs leukocytes and platelets, especially activated platelets and platelet‐leukocyte aggregates. In this article, the capability of Immunopure is evaluated from clinical perspective based on a clinical trial in Japan/Europe. As a result, Immunopure is comparable to other products in clinical effectiveness and indicated for the treatment of patients with refractory moderate ulcerative colitis, making it highly useful in clinical practice.

Difficulty removing dialysis cuff catheter after its adhesion to the right atrium

We describe the case of an elderly Japanese female who had experienced diabetic nephropathy since the year 20xx and had been undergoing dialysis treatment while receiving vascular access interventional therapy (VAIVT) for arteriovenous fistula (AVF) occlusion. The patient visited the clinic/hospital in 20xx+10 with the AVF occlusion; emergency VAIVT was performed but blood flow could not be resumed. The patient was not admitted and was treated as an outpatient, and thus a cuff catheter (Split stream catheter: SST28 cm, Medcomp) was inserted. An infection developed and was successfully treated with antibiotics. The dialysis treatment continued without issue. One year after the cuff catheter's insertion, the patient was admitted due difficulty breathing. Despite continued dialysis treatment with the catheter, the patient died 15 days post-admission. The removal of the catheter proved to be difficult. An autopsy was approved, and the area around the catheter was examined. The adhesion of the catheter to the right atrium was observed, but no infection was detected in the bloodstream. This case illustrates that dialysis with the use of a cuff catheter can be effective.

Inhibition of xanthine oxidase ameliorates functional and metabolic impairment in type 2 diabetic hearts under pressure overload

Background

We recently reported that upregulated AMP deaminase (AMPD), via reduction in the tissue adenine nucleotide pool, contributes to exacerbation of diastolic dysfunction under pressure overload in OLETF, a rat model of obese type 2 diabetes (T2DM). Upregulated AMPD also possibly promotes xanthine oxidase (XO)-mediated ROS production, since AMPD deaminases AMP to IMP, which is further converted to inosine, providing substrates of XO, hypoxanthine and xanthine. Here, we examined the hypothesis that inhibition of XO ameliorates the pressure overload-induced diastolic dysfunction by suppression of ROS-mediated mitochondrial dysfunction and/or vascular dysfunction in T2DM rats.

Methods and results

Metabolomic analyses revealed that levels of xanthine and uric acid in the LV myocardium were significantly higher by 37% and 51%, respectively, in OLETF than in LETO, non-diabetic control rats, under the condition of phenylephrine-induced pressure overloading (200–230 mmHg). Myocardial XO activity in OLETF was 57.9% higher than that in LETO, which may be attributed to 31% higher level of inosine, a positive regulator of XO, in OLETF than in LETO. The activity of XO was significantly attenuated by administration of topiroxostat, an XO inhibitor at 0.5 mg/kg/day for 14 days. Pressure volume loop analyses showed that the pressure overloading resulted in significantly higher LVEDP in OLETF than in LETO (18.3±1.5 vs. 12.2±1.3 mmHg, p&lt;0.05, n=7), though LVEDPs at baseline were comparable in OLETF and LETO (5.6±0.4 vs. 4.7±0.7 mmHg). Treatment with topiroxostat significantly suppressed the pressure overload-induced elevation of LVEDP in OLETF (18.3±1.5 vs. 11.3±1.1 mmHg, p&lt;0.05) but not in LETO. Under the condition of pressure overloading, Ea/Ees, an index for ventricular-arterial coupling, was higher in OLETF than in LETO (2.3±0.3 vs. 1.6±0.3, p&lt;0.05), and it was also improved by topiroxostat in OLETF (1.2±0.2, p&lt;0.05). Myocardial ATP content was lower in OLETF than in LETO (2966±400 vs. 1818±171 nmol/g wet tissue, p&lt;0.05), and treatment with topiroxostat significantly restored the ATP level (2629±307 nmol/g wet tissue). The LV myocardium of OLETF under pressure overload showed significantly higher level of malondialdehyde and 4-hydroxynonenal, an indicator of lipid peroxidation, than that of LETO. Measurement of oxygen consumption rate by Seahorse XFe96 Analyzer in mitochondria isolated from LV tissues revealed that state 3 respiration was significantly suppressed in OLETF by 43% compared to LETO, and it was restored by treatment with topiroxostat.

Conclusion

Both activity and substrates of XO are increased in T2DM hearts, in which upregulation of AMPD may play a role. Inhibition of XO ameliorates pressure overload-induced diastolic dysfunction and improves ventricular-arterial coupling in diabetic hearts, most likely through protection of mitochondrial function from ROS-mediated injury.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grant-in-aid for Scientific Research (#26461132, #17K09584) from the Japanese Society for the Promotion of Science