Timing of Assessment of Humoral and Cell-Mediated Immunity after Influenza Vaccination.

Assessment of the immune response to influenza vaccines should include an assessment of both humoral and cell-mediated immunity. However, there is a lack of consensus regarding the timing of immunological assessment of humoral and cell-mediated immunity after vaccination. Therefore, we investigated the timing of immunological assessments after vaccination using markers of humoral and cell-mediated immunity. In the 2018/2019 influenza season, blood was collected from 29 healthy adults before and after vaccination with a quadrivalent inactivated influenza vaccine, and we performed serial measurements of humoral immunity (hemagglutination inhibition [HAI] and neutralizing antibody [NT]) and cell-mediated immunity (interferon-gamma [IFN-γ]). The HAI and NT titers before and after vaccination were strongly correlated, but no correlation was observed between the markers of cell-mediated and humoral immunity. The geometric mean titer and geometric mean concentration of humoral and cellular immune markers increased within 2 weeks after vaccination and had already declined by 8 weeks. This study suggests that the optimal time to assess the immune response is 2 weeks after vaccination. Appropriately timed immunological assessments can help ensure that vaccination is effective.

Enhancing carbapenem antimicrobial dosing optimization: synergy of antimicrobial stewardship teams and ward-based clinical pharmacists.

Antimicrobial-product package inserts and insufficient staffing impede routine carbapenem monitoring in the inpatient setting in Japan. The collaboration between antimicrobial stewardship teams and clinical pharmacists was associated with a sustained improvement in carbapenem dosing optimization. Our findings could be of use to countries with inadequate monitoring of carbapenem antimicrobial use.

A false decrease in the automatically measured atrial pacing threshold when using the automatic pacing threshold adjustment algorithm.

Automatic pacing threshold adjustment algorithms and remote monitoring are widely used to improve the utility of pacemakers and ensure patient safety. However, healthcare providers involved in the management of permanent pacemakers should know the potential pitfalls of these functions. In this report, we present a case of atrial pacing failure induced by the automatic pacing threshold adjustment algorithm that went unnoticed even under remote monitoring.

Comparison of Needle Knife versus Scissors Forceps for Colorectal Endoscopic Submucosal Dissection: A Prospective Randomized Study.

BACKGROUND AND AIM: To evaluate the efficacy and safety of a grasping-type knife, called Clutch Cutter (CC), for colorectal endoscopic submucosal dissection (C-ESD). METHODS: This was a randomized prospective study. Patients who underwent C-ESD for colorectal neoplasms >20 mm and <50 mm in size were enrolled, dividing into two groups: ESD using needle type of dual knife alone (D-group) and circumferential incision using dual knife followed by submucosal dissection using CC (CC-group). The primary outcome was the self-completion rate. The secondary outcomes were intraoperative complication rate, procedure time, and en bloc resection rate. RESULTS: A total of 45 patients were allocated to the D-group and 43 to the CC-group were allocated. The self-completion rate was higher in the CC-group (87% [39/45] vs. 98% [42/43]). All of the six patients with an incomplete procedure in the D-group were completely resected with CC use. The intraoperative complication rate was not significant in either group (D vs. CC: 2% vs. 0%). The mean procedure time was significantly shorter in the D-group than that in the CC-group (62.0 vs. 81.1 min; p = 0.0036). The en bloc resection rate was 100% in the D-group and 98% in the CC-group. CONCLUSIONS: While dual knife use is superior to CC in terms of time efficiency, the use of CC may be a safe and efficacious option for achieving complete C-ESD.

Correlation between Antimicrobial Resistance and the Hospital-Wide Diverse Use of Broad-Spectrum Antibiotics by the Antimicrobial Stewardship Program in Japan.

Increased antibiotic use and antibiotic homogeneity cause selective pressure. This study investigated the correlation between antibiotic diversity and antimicrobial resistance (AMR) in Gram-negative organisms. The days of therapy/100 patient-days (DOT) for four broad-spectrum antibiotic classes were evaluated for 2015-2022. The antibiotic heterogeneity index (AHI) for the equal use of four classes (25%) and the modified AHI for the equal use of three classes (30%), excluding fluoroquinolones (10%), were measured (target: 1.0). Quarterly antibiotic use markers and the resistance rates against ≥2 anti-Pseudomonas antibiotics were compared. The DOT value was 9.94, and the relative DOT were 34.8% for carbapenems, 32.1% for piperacillin/tazobactam, 24.3% for fourth generation cephalosporins/ceftazidime/aztreonam, and 8.9% for fluoroquinolones. Although no correlation was found between the total DOT and the resistance rate for any bacterium, a significant negative correlation was found between the heterogeneity indices and resistance rates for Pseudomonas aeruginosa and Klebsiella pneumoniae. The significant cutoffs that discriminate the risk of resistance were 0.756 for the AHI and 0.889 for the modified AHI for K. pneumoniae. Antibiotic diversity is more important in preventing AMR than overall antibiotic use. The ideal ratio of broad-spectrum antibiotics should be studied for diversified use to prevent AMR.

Pearson syndrome: a multisystem mitochondrial disease with bone marrow failure.

Pearson syndrome (PS) is a rare fatal mitochondrial disorder caused by single large-scale mitochondrial DNA deletions (SLSMDs). Most patients present with anemia in infancy. Bone marrow cytology with vacuolization in erythroid and myeloid precursors and ring-sideroblasts guides to the correct diagnosis, which is established by detection of SLSMDs. Non hematological symptoms suggesting a mitochondrial disease are often lacking at initial presentation, thus PS is an important differential diagnosis in isolated hypogenerative anemia in infancy. Spontaneous resolution of anemia occurs in two-third of patients at the age of 1-3 years, while multisystem non-hematological complications such as failure to thrive, muscle hypotonia, exocrine pancreas insufficiency, renal tubulopathy and cardiac dysfunction develop during the clinical course. Some patients with PS experience a phenotypical change to Kearns-Sayre syndrome. In the absence of curative therapy, the prognosis of patients with PS is dismal. Most patients die of acute lactic acidosis and multi-organ failure in early childhood. There is a great need for the development of novel therapies to alter the natural history of patients with PS.

Pearson syndrome-like anemia induced by accumulation of mutant mtDNA and anemia with imbalanced white blood cell lineages induced by Drp1 deletion in a murine model.

Regulation of mitochondrial respiration and morphology is important for maintaining steady-state hematopoiesis, yet few studies have comparatively evaluated the effects of abnormal mitochondrial respiration and dynamics on blood-cell differentiation in isolation or combination. This study sought to explore these effects in mouse models with one or both of the following deficits: a large-scale deletion of mitochondrial DNA (ΔmtDNA), accumulated to varying extents, or knockout of the mitochondrial fission factor Drp1. Each deficit was found to independently provoke anemia but with clearly different manifestations. The former showed signs of aberrant respiration, analogous to Pearson syndrome, while the latter showed signs of abnormal mitochondrial dynamics and was associated with changes in the relative proportions of leukocyte lineages. Combining these deficits acted to amplify abnormal iron metabolism in erythropoiesis, exacerbating anemia in an additive manner. Our results indicate that mitochondrial respiration and dynamics play distinct roles in different sets of processes and cell lineages in hematopoietic differentiation.

Aberrant RNA processing contributes to the pathogenesis of mitochondrial diseases in trans-mitochondrial mouse model carrying mitochondrial tRNALeu(UUR) with a pathogenic A2748G mutation.

Mitochondrial tRNAs are indispensable for the intra-mitochondrial translation of genes related to respiratory subunits, and mutations in mitochondrial tRNA genes have been identified in various disease patients. However, the molecular mechanism underlying pathogenesis remains unclear due to the lack of animal models. Here, we established a mouse model, designated 'mito-mice tRNALeu(UUR)2748', that carries a pathogenic A2748G mutation in the tRNALeu(UUR) gene of mitochondrial DNA (mtDNA). The A2748G mutation is orthologous to the human A3302G mutation found in patients with mitochondrial diseases and diabetes. A2748G mtDNA was maternally inherited, equally distributed among tissues in individual mice, and its abundance did not change with age. At the molecular level, A2748G mutation is associated with aberrant processing of precursor mRNA containing tRNALeu(UUR) and mt-ND1, leading to a marked decrease in the steady-levels of ND1 protein and Complex I activity in tissues. Mito-mice tRNALeu(UUR)2748 with ≥50% A2748G mtDNA exhibited age-dependent metabolic defects including hyperglycemia, insulin insensitivity, and hepatic steatosis, resembling symptoms of patients carrying the A3302G mutation. This work demonstrates a valuable mouse model with an inheritable pathological A2748G mutation in mt-tRNALeu(UUR) that shows metabolic syndrome-like phenotypes at high heteroplasmy level. Furthermore, our findings provide molecular basis for understanding A3302G mutation-mediated mitochondrial disorders.

Potential of the TRPM7 channel as a novel therapeutic target for pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is an intractable vascular disease characterized by a progressive increase in pulmonary vascular resistance caused by pulmonary vascular remodeling, which ultimately leads to right-sided heart failure. PAH remains incurable, despite the development of PAH-targeted therapeutics centered on pulmonary artery relaxants. It is necessary to identify the target molecules that contribute to pulmonary artery remodeling. Transient receptor potential (TRP) channels have been suggested to modulate pulmonary artery remodeling. Our study focused on the transient receptor potential ion channel subfamily M, member 7, or the TRPM7 channel, which modulates endothelial-to-mesenchymal transition and smooth muscle proliferation in the pulmonary artery. In this review, we summarize the role and expression profile of TRPM7 channels in PAH progression and discuss TRPM7 channels as possible therapeutic targets. In addition, we discuss the therapeutic effect of a Chinese herbal medicine, Ophiocordyceps sinensis (OCS), on PAH progression, which partly involves TRPM7 inhibition.

Comparison of the Hemagglutination Inhibition Titers against Influenza Vaccine Strains in Japan from the 2017/2018 to 2021/2022 Seasons Using a Single Set of Serum Samples.

In Japan, inactivated influenza vaccines are used. We measured titers of antibodies to vaccine strains of three influenza types-influenza A (H1N1), influenza A (H3N2), and influenza B/Victoria-from the 2017/2018 to 2021/2022 seasons, but not for influenza A (H3N2) from the 2018/2019 season, using a single set of serum samples from 34 healthy volunteers, and assessed the consistency in antibody positivity between seasons. The antibody titers in the 2017/2018 season were used as a reference. The influenza A (H1N1) antibody titer in 2019/2020 did not differ significantly from that in the 2017/2018 season, but the titers varied in the two subsequent seasons. The influenza A (H3N2) antibody titers toward the 2019/2020, 2020/2021, and 2021/2022 seasonal viruses differed significantly from that in the 2017/2018 season. The influenza B/Victoria antibody titer toward the 2019/2020 seasonal antigen differed from that in the 2017/2018 season, and the antibody positivity was inconsistent between seasons; however, the antibody titer in the 2020/2021 season did not differ significantly from those in the prior two seasons, and the antibody positivity was consistent between seasons. Antibody titers and their consistency can be used to evaluate cross-immunity of antibodies.

Correction of thrombocytopenia caused by linezolid with scheduled sequential tedizolid use in patients with vertebral osteomyelitis by antibiotic resistant Gram-positive organisms.

INTRODUCTION: Because of thrombocytopenia, linezolid treatment tends to be stopped before the completion of therapy for complicated infections that require prolonged antimicrobial administration. In contrast, tedizolid shows a favorable hematologic profile. The primary end-point of this study was to evaluate the efficacy of switching treatment to tedizolid in patients who developed thrombocytopenia during linezolid therapy. METHODS: This retrospective study was conducted in patients with vertebral osteomyelitis (VO) caused by antibiotic-resistant Gram-positive bacteria. Treatment failure was defined as the reappearance of infection signs within 2 weeks after stopping tedizolid and discontinuation of tedizolid because of continued thrombocytopenia or other adverse effects. RESULTS: Eight patients with native VO (n = 3) and postoperative VO (n = 5) were included in the study. The causative organisms were MRSA in all patients except one. Platelet counts decreased from 35.2 ± 11.5 × 104/mm3 to 17.8 ± 6.2 × 104/mm3 during linezolid therapy and improved without washout period in all patients after switching to tedizolid on days 5-7 (28.6 ± 4.9 × 104/mm3, p = 0.002). Tedizolid therapy was completed and treatment failure was not observed in any patient. The duration of treatment was 20.0 ± 11.2 days for linezolid and 30.3 ± 9.5 days for tedizolid (total, 50.3 ± 10.7 days). One patient died because of underlying disease, and there was no recurrence in the remaining 7 patients (median follow-up 501 days). CONCLUSIONS: Switching therapy to tedizolid improved thrombocytopenia that occurred during linezolid therapy, and it enabled the completion of therapy for VO patients.

Validation of Vancomycin Area under the Concentration-Time Curve Estimation by the Bayesian Approach Using One-Point Samples for Predicting Clinical Outcomes in Patients with Methicillin-Resistant Staphylococcus aureus Infections.

Area under the concentration-time curve (AUC)-guided vancomycin treatment is associated with decreased nephrotoxicity. It is preferable to obtain two samples to estimate the AUC. This study examined the usefulness of AUC estimation via trough concentration (Cmin)-only sampling of 260 adults infected with methicillin-resistant Staphylococcus aureus (MRSA) who received vancomycin. The exact Cmin sampling time was used for Bayesian estimation. A significantly higher early treatment response was observed in patients with a day 2 AUC ≥ 400 µg·h/mL than those with <400 µg·h/mL, and a significantly higher early nephrotoxicity rate was observed in patients with a day 2 AUC ≥ 600 µg·h/mL than those with <600 µg·h/mL. These AUC cutoff values constituted independent factors for each outcome. In sub-analysis, the discrimination ability for early clinical outcomes using these AUC cutoffs was confirmed only in patients with q12 vancomycin administration. A significant difference in early treatment response using the 400 µg·h/mL cutoff was obtained only in patients with low-risk infections. The usefulness of the vancomycin AUC target to decrease nephrotoxicity while assuring clinical efficacy was even confirmed with a single Cmin measurement. However, assessment with two samples might be required in patients with q24 administration or high/moderate-risk MRSA infections.

Enhanced loading dose of teicoplanin for three days is required to achieve a target trough concentration of 20 µg/mL in patients receiving continuous venovenous haemodiafiltration with a low flow rate.

INTRODUCTION: Because of its lower risk of renal toxicity than vancomycin, teicoplanin is the preferred treatment for methicillin-resistant Staphylococcus aureus infection in patients undergoing continuous venovenous haemodiafiltration (CVVHDF) in whom renal function is expected to recover. The dosing regimen for achieving a trough concentration (Cmin) of ≥20 µg/mL remains unclear in patients on CVVHDF using the low flow rate adopted in Japan. METHODS: The study was conducted in patients undergoing CVVHDF with a flow rate of <20 mg/kg/h who were treated with teicoplanin. We adopted three loading dose regimens for the initial 3 days: the conventional regimen, a high-dose regimen (four doses of 10 mg/kg), and an enhanced regimen (four doses of 12 mg/kg). The initial Cmin was obtained at 72 h after the first dose. RESULTS: Overall, 60 patients were eligible for study inclusion. The proportion of patients achieving the Cmin target was significantly higher for the enhanced regimen than for the high-dose regimen (52.9% versus 8.3%, p = 0.003). In multivariate analysis, the enhanced regimen (odds ratio [OR] = 39.93, 95% confidence interval [CI] = 5.03-317.17) and hypoalbuminaemia (OR = 0.04, 95% CI = 0.01-0.44) were independent predictors of the achievement of Cmin ≥ 20 µg/mL. CONCLUSIONS: An enhanced teicoplanin regimen was proposed to treat complicated or invasive infections by methicillin-resistant Staphylococcus aureus in patients receiving CVVHDF even with a low flow rate.

Mitochondrial DNA mutations are involved in the acquisition of cisplatin resistance in human lung cancer A549 cells.

The efficacy of cisplatin (CDDP) has been demonstrated in the treatment of various cancers as monotherapy and combination therapy with immunotherapy. However, acquired CDDP resistance is a major obstacle to successful treatment. In the present study, the mechanisms underlying acquired CDDP resistance were examined using ACR20 cells, which are CDDP­resistant cells derived from A549 lung cancer cells. CDDP induces cytotoxicity by binding nuclear DNA and generating reactive oxygen species (ROS). Contrary to our expectation, ROS levels were elevated in ACR20 cells not treated with CDDP. Pretreatment with an ROS inhibitor enhanced the sensitivity of ACR20 cells to CDDP and prevented the activation of nuclear factor (NF)­ÐºB signaling and upregulation of inhibitor of apoptosis proteins (IAPs). Notably, evaluation of the mitochondrial oxygen consumption rate and mitochondrial superoxide levels revealed a deterioration of mitochondrial function in ACR20 cells. Mitochondrial DNA PCR­RFLP analysis revealed four mutations with varying percentage levels in ACR20 cells. In addition, in cytoplasmic hybrids with mitochondria from ACR20 cells, intrinsic ROS levels were elevated, expression of IAPs was increased, and complex I activity and sensitivity to CDDP were decreased. Analysis of three­dimensional structure data indicated that a mutation (ND2 F40L) may impact the proton translocation pathway, thereby affecting mitochondrial complex I activity. Together, these findings suggest that intrinsic ROS levels were elevated by mitochondrial DNA mutations, which decreased the sensitivity to CDDP via activation of NF­κB signaling and induction of IAP expression in ACR20 cells. These findings indicate that newly identified mutations in mitochondrial DNA may lead to acquired cisplatin resistance in cancer.

Information provision and retrieval by registered salespersons from consumers during over-the-counter drug sales - a questionnaire survey.

BACKGROUND: In Japan, non-pharmacists who are accredited as registered salespersons can sell over-the-counter (OTC) drugs, and they play a very important role in supporting proper OTC drug use by consumers. The purpose of this study was to evaluate information provided to and information collected from consumers, and cooperation with pharmacists during OTC drug sales by registered salespersons, and to clarify their related concerns and behaviors. METHODS: A cross-sectional questionnaire-based survey of 385 registered salespersons working at 56 drugstores throughout Japan was conducted. Based on the questionnaire survey, the frequency of information provision/collection in various categories was determined for the registered salespersons. The relation between concerns of registered salespersons relating to OTC drug sales and the frequency of information provision/collection was examined. The frequency of consultation of registered salespersons with a pharmacist was calculated for registered salespersons with/without in-store pharmacists. The χ-square test or Fisher's exact test was performed to assess the significance of differences. RESULTS: Two hundred and seven registered salespersons (53.7%) responded completely. A greater number of OTC drug purchasers per day was associated with a greater frequency of information provision about "side effects" and information collection about "favorite items" (alcohol, tobacco, health foods, etc.) (p < 0.05). One hundred and thirty-nine (67.2%) participants had concerns about "interactions between OTC drugs and prescription drugs", and these concerns were related to the frequency of information provision/collection (p < 0.05). Regarding the frequency of consultation with a pharmacist, 35 of 46 participants (76.1%) working with pharmacists answered "always" or "usually", whereas only 19 of 161 participants (11.8%) working without full-time pharmacists answered "always" or "usually". More than half of the registered salespersons thought that cooperation with a pharmacist was necessary when they were "asked about concomitant use with prescription drugs" or "told that side effects happened." CONCLUSIONS: The results of this study show that experienced registered salespersons selling OTC drugs are more likely to collect information from consumers and to provide information to consumers. It appears to be important for registered salespersons to cooperate with pharmacists in order to provide and collect appropriate information about concomitant medications.

Changes in Cell-Mediated Immunity (IFN-γ and Granzyme B) Following Influenza Vaccination.

Interferon gamma (IFN-γ) is considered a key moderator of cell-mediated immunity. However, little is known about its association with granzyme B, which plays an important role in the effector function of cytotoxic T lymphocytes (CTLs). In the present study, we collected blood samples from 32 healthy adults before and after vaccination with inactivated influenza vaccine in 2017/18 to measure the levels of IFN-γ and granzyme B, which play roles in cell-mediated immunity, and hemagglutination inhibition (HAI) antibody, which plays a role in humoral immunity. The levels of IFN-γ and granzyme B were significantly correlated both before and after vaccination. Furthermore, the post-vaccine fold increases in the IFN-γ and granzyme B levels were significantly correlated. The levels of IFN-γ and granzyme B decreased five months after vaccination in more than half of the subjects who exhibited an increase in IFN-γ and granzyme B at two weeks post-vaccination. This is the first study to investigate the correlation between IFN-γ and granzyme B levels following influenza vaccination. Our study suggests that both IFN-γ and granzyme B can be used as markers of cell-mediated immunity.

A high mutation load of m.14597A>G in MT-ND6 causes Leigh syndrome.

Leigh syndrome (LS) is an early-onset progressive neurodegenerative disorder associated with mitochondrial deficiency. m.14597A>G (p.Ile26Thr) in the MT-ND6 gene was reported to cause Leber's hereditary optic neuropathy (LHON) or dementia/dysarthria. In previous reports, less than 90% heteroplasmy was shown to result in adult-onset disease. Here, by whole mitochondrial sequencing, we identified m.14597A>G mutation of a patient with LS. PCR-RFLP analysis on fibroblasts from the patient revealed a high mutation load (> 90% heteroplasmy). We performed functional assays using cybrid cell models generated by fusing mtDNA-less rho0 HeLa cells with enucleated cells from patient fibroblasts carrying the m.14597A>G variant. Cybrid cell lines bearing the m.14597A>G variant exhibited severe effects on mitochondrial complex I activity. Additionally, impairment of cell proliferation, decreased ATP production and reduced oxygen consumption rate were observed in the cybrid cell lines bearing the m.14597A>G variant when the cells were metabolically stressed in medium containing galactose, indicating mitochondrial respiratory chain defects. These results suggest that a high mutation load of m.14597A>G leads to LS via a mitochondrial complex I defect, rather than LHON or dementia/dysarthria.

Effects of Dual Initial Combination Therapy With Macitentan Plus Riociguat or Macitentan Plus Selexipag on Hemodynamics in Patients With Pulmonary Arterial Hypertension (SETOUCHI-PH Study)　- Protocol of a Multicenter Randomized Control Trial.

Background: The latest guideline from the European Society of Cardiology and European Respiratory Society recommends initial combination therapy with oral pulmonary arterial hypertension (PAH)-specific drugs in PAH patients with World Health Organization functional class (WHO-FC) II or III. However, whether this initial combination therapy improves hemodynamics and clinical failure events regardless of the combination of PAH-specific drugs remains unknown. This study was designed to evaluate whether the initial combination therapy with macitentan plus riociguat or macitentan plus selexipag showed equal efficacy in reducing pulmonary vascular resistance (PVR) 8 months after administration. Methods and Results: This study is a multicenter randomized control trial. PAH subjects with WHO-FC II or III will be randomized (1 : 1) into initial combination therapy with either macitentan plus riociguat or macitentan plus selexipag, and will be observed 8 months after the initiation of treatment. The primary endpoint will be the difference in the change ratio of PVR from baseline to after 8 months of treatment. Conclusions: The SETOUCHI-PH study will clarify whether initial combination therapy with macitentan plus riociguat or macitentan plus selexipag results in equal reductions in PVR 8 months after administration.

Substantial involvement of TRPM7 inhibition in the therapeutic effect of Ophiocordyceps sinensis on pulmonary hypertension.

Ophiocordyceps sinensis (OCS), an entomopathogenic fungus, is known to exert antiproliferative and antitissue remodeling effects. Vascular remodeling and vasoconstriction play critical roles in the development of pulmonary hypertension (PH). The therapeutic potential of OCS for PH was investigated using rodent PH models, and cultured pulmonary artery endothelial and smooth muscle cells (PAECs and PASMCs), with a focus on the involvement of TRPM7. OCS ameliorated the development of PH, right ventricular hypertrophy and dysfunction in the monocrotaline-induced PH rats. The genetic knockout of TRPM7 attenuated the development of PH in mice with monocrotaline pyrrole-induced PH. TRPM7 was associated with medial hypertrophy and the plexiform lesions in rats and humans with PH. OCS suppressed proliferation of PASMCs derived from the PH patients. Ethanol extracts of OCS inhibited TRPM7-like current, TGF-ß2-induced endothelial-mesenchymal transition, IL-6-induced STAT3 phosphorylation, and PDGF-induced Akt phosphorylation in PAECs or PASMCs. These inhibitory effects were recapitulated by either siRNA-mediated TRPM7 knockdown or treatment with TRPM7 antagonist FTY-720. OCS and FTY-720 induced vasorelaxation in the isolated normal human pulmonary artery. As a result, the present study proposes the therapeutic potential of OCS for the treatment of PH. The inhibition of TRPM7 is suggested to underlie the therapeutic effect of OCS.

Attempts to understand the mechanisms of mitochondrial diseases: The reverse genetics of mouse models for mitochondrial disease.

BACKGROUND: Mitochondrial disease is a general term for a disease caused by a decline in mitochondrial function. The pathology of this disease is extremely diverse and complex, and the mechanism of its pathogenesis is still unknown. Using mouse models that develop the disease via the same processes as in humans is the easiest path to understanding the underlying mechanism. However, creating a mouse model is extremely difficult due to the lack of technologies that enable editing of mitochondrial DNA (mtDNA). SCOPE OF REVIEW: This paper outlines the complex pathogenesis of mitochondrial disease, and the difficulties in producing relevant mouse models. Then, the paper provides a detailed discussion on several mice created with mutations in mtDNA. The paper also introduces the pathology of mouse models with mutations including knockouts of nuclear genes that directly affect mitochondrial function. MAJOR CONCLUSIONS: Several mice with mtDNA mutations and those with nuclear DNA mutations have been established. Although these models help elucidate the pathological mechanism of mitochondrial disease, they lack sufficient diversity to enable a complete understanding. Considering the variety of factors that affect the cause and mechanism of mitochondrial disease, it is necessary to account for this background diversity in mouse models as well. GENERAL SIGNIFICANCE: Mouse models are indispensable for understanding the pathological mechanism of mitochondrial disease, as well as for searching new treatments. There is a need for the creation and examination of mouse models with more diverse mutations and altered nuclear backgrounds and breeding environments.