Mitochondrial DNA mutations in extremely preterm infants with bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a serious chronic lung disease affecting extremely preterm infants. While mitochondrial dysfunction has been investigated in various medical conditions, limited research has explored mitochondrial DNA (mtDNA) gene mutations, specifically in BPD. This study aimed to evaluate mitochondrial mtDNA gene mutations in extremely preterm infants with BPD. In this prospective observational study, we enrolled a cohort of extremely preterm infants diagnosed with BPD. Clinical data were collected to provide comprehensive patient profiles. Peripheral blood mononuclear cells were isolated from whole-blood samples obtained within a defined timeframe. Subsequently, mtDNA extraction and sequencing using next-generation sequencing technology were performed to identify mtDNA gene mutations. Among the cohort of ten extremely preterm infants with BPD, mtDNA sequencing revealed the presence of mutations in seven patients, resulting in a total of twenty-one point mutations. Notably, many of these mutations were identified in loci associated with critical components of the respiratory chain complexes, vital for proper mitochondrial function and cellular energy production. This pilot study provides evidence of mtDNA point mutations in a subset of extremely preterm infants with BPD. These findings suggest a potential association between mitochondrial dysfunction and the pathogenesis of BPD. Further extensive investigations are warranted to unravel the mechanisms underlying mtDNA mutations in BPD.

Selection of iPSCs without mtDNA deletion for autologous cell therapy in a patient with Pearson syndrome

Screening for genetic defects in the cells should be examined for clinical application. The Pearson syndrome (PS) patient harbored nuclear mutations in the POLG and SSBP1 genes, which could induce systemic large-scale mitochondrial genome (mtDNA) deletion. We investigated iPSCs with mtDNA deletions in PS patient and whether deletion levels could be maintained during differentiation. The iPSC clones derived from skin fibroblasts (9% deletion) and blood mononuclear cells (24% deletion) were measured for mtDNA deletion levels. Of the 13 skin-derived iPSC clones, only 3 were found to be free of mtDNA deletions, whereas all blood-derived iPSC clones were found to be free of deletions. The iPSC clones with (27%) and without mtDNA deletion (0%) were selected and performed in vitro and in vivo differentiation, such as embryonic body (EB) and teratoma formation. After differentiation, the level of deletion was retained or increased in EBs (24%) or teratoma (45%) from deletion iPSC clone, while, the absence of deletions showed in all EBs and teratomas from deletion-free iPSC clones. These results demonstrated that non-deletion in iPSCs was maintained during in vitro and in vivo differentiation, even in the presence of nuclear mutations, suggesting that deletion-free iPSC clones could be candidates for autologous cell therapy in patients. [BMB Reports 2023; 56(8): 463-468].

The feasibility of early response evaluation using superb microvascular imaging one day after transcatheter arterial chemoembolization for hepatocellular carcinoma

PURPOSE

The purpose of this study was to determine the feasibility of early Superb microvascular imaging (SMI) for prediction of the effect of HCC treatment after transcatheter arterial chemoembolization (TACE).

MATERIALS AND METHODS

A total of 96 HCCs (70 patients) treated with TACE between September 2021 and May 2022 were included in this study. SMI, Color Doppler imaging (CDI), and Power Doppler imaging (PDI) were performed the day after TACE for evaluation of intratumoral vascularity of the lesion using an Aplio500 ultrasound scanner (Toshiba Medical Systems, Corporation, Tochigi, Japan). Grading of the vascular presence was performed using a five-point scale. A dynamic CT image taken after 29-42 days was used for comparison of sensitivity, specificity, and accuracy for detection of tumor vascularity between SMI, CDI, and PDI. Univariate and multivariate analysis were performed for assessment of factors affecting intratumoral vascularity.

RESULTS

Fifty-eight lesions (60%) showed complete remission (CR) and 38 lesions (40%) showed partial response (PR) or no response at 29-42 days on Multi-detector Computed Tomography (MDCT) after TACE. SMI showed sensitivity of 86.84% for detection of intratumoral flow, which was significantly higher compared with that of CDI (10.53%, p < 0.001) and PDI (36.84%, p < 0.001). The results of multivariate analysis indicated that tumor size was a significant factor in detection of blood flow using the SMI technique.

CONCLUSION

Early SMI may be utilized as an adjunctive diagnostic test for evaluation of treated lesions after TACE, particularly when the location of the tumor is in an area of the liver where a suitable sonic window can be identified.

Therapeutic Potency of Induced Pluripotent Stem-Cell-Derived Corneal Endothelial-like Cells for Corneal Endothelial Dysfunction

Corneal endothelial cells (CECs) do not proliferate or recover after illness or injury, resulting in decreased cell density and loss of pump/barrier function. Considering the shortage of donor cornea, it is vital to establish robust methods to generate CECs from induced pluripotent stem cells (iPSCs). We investigated the efficacy and safety of transplantation of iPSC-derived CECs into a corneal endothelial dysfunction (CED) rabbit model. iPSCs were generated from human fibroblasts. We characterized iPSCs by demonstrating the gene expression of the PSC markers OCT4, SOX2, TRA-1-60, and NANOG, teratoma formation, and differentiation into three germ layers. Differentiation of iPSCs into CECs was induced via neural crest cell (NCC) induction. CEC markers were detected using immunofluorescence and gene expression was analyzed using quantitative real-time PCR (qRT-PCR). After culturing iPSC-derived NCCs, we found the expression of zona occludens-1 (ZO-1) and Na⁺/K⁺ ATPase and a hexagonal morphology. ATP1A1, COL8A1, and AQP1 mRNA expression was higher in iPSC-derived CECs than in iPSCs and NCCs. We performed an injection of iPSC-derived CECs into the anterior chamber of a CED rabbit model and found improved levels of corneal transparency. We also found increased numbers of ZO-1- and ATP1A1-positive cells in rabbit corneas in the iPSC-derived CEC transplantation group. Usage of the coating material vitronectin (VTN) and fasudil resulted in good levels of CEC marker expression, demonstrated with Western blotting and immunocytochemistry. Combination of the VTN coating material and fasudil, instead of FNC mixture and Y27632, afforded the best results in terms of CEC differentiation's in vitro and in vivo efficacy. Successful transplantation of CEC-like cells into a CED animal model confirms the therapeutic efficacy of these cells, demonstrated by the restoration of corneal clarity. Our results suggest that iPSC-derived CECs can be a promising cellular resource for the treatment of CED.

Dysfunctional pancreatic cells differentiated from induced pluripotent stem cells with mitochondrial DNA mutations

Diabetes mellitus (DM) is a serious disease in which blood sugar levels rise abnormally because of failed insulin production or decreased insulin sensitivity. Although many studies are being conducted for the treatment or early diagnosis of DM, it is not fully understood how mitochondrial genome (mtDNA) abnormalities appear in patients with DM. Here, we induced iPSCs from fibroblasts, PBMCs, or pancreatic cells of three patients with type 2 DM (T2D) and three patients with non-diabetes counterpart. The mtDNA mutations were detected randomly without any tendency among tissues or patients. In T2D patients, 62% (21/34) of iPSC clones harbored multiple mtDNA mutations, of which 37% were homoplasmy at the 100% mutation level compared to only 8% in non-diabetes. We next selected iPSC clones that were a wild type or carried mutations and differentiated into pancreatic cells. Oxygen consumption rates were significantly lower in cells carrying mutant mtDNA. Additionally, the mutant cells exhibited decreased production of insulin and reduced secretion of insulin in response to glucose. Overall, the results suggest that screening mtDNA mutations in iPSCs from patients with T2D is an essential step before pancreatic cell differentiation for disease modeling or autologous cell therapy.

Mitochondrial genome mutations and neuronal dysfunction of induced pluripotent stem cells derived from patients with Alzheimer's disease

OBJECTIVES

Patient-derived induced pluripotent stem cells (iPSCs) are materials that can be used for autologous stem cell therapy. We screened mtDNA mutations in iPSCs and iPSC-derived neuronal cells from patients with Alzheimer's disease (AD). Also, we investigated whether the mutations could affect mitochondrial function and deposition of β-amyloid (Aβ) in differentiated neuronal cells.

MATERIALS AND METHODS

mtDNA mutations were measured and compared among iPSCs and iPSC-derived neuronal cells. The selected iPSCs carrying mtDNA mutations were subcloned, and then their growth rate and neuronal differentiation pattern were analyzed. The differentiated cells were measured for mitochondrial respiration and membrane potential, as well as deposition of Aβ.

RESULTS

Most iPSCs from subjects with AD harbored ≥1 mtDNA mutations, and the number of mutations was significantly higher than that from umbilical cord blood. About 35% and 40% of mutations in iPSCs were shared with isogenic iPSCs and their differentiated neuronal precursor cells, respectively, with similar or different heteroplasmy. Furthermore, the mutations in clonal iPSCs were stable during extended culture and neuronal differentiation. Finally, mtDNA mutations could induce a growth advantage with higher viability and proliferation, lower mitochondrial respiration and membrane potential, as well as increased Aβ deposition.

CONCLUSION

This study demonstrates that mtDNA mutations in patients with AD could lead to mitochondrial dysfunction and accelerated Aβ deposition. Therefore, early screening for mtDNA mutations in iPSC lines would be essential for developing autologous cell therapy or drug screening for patients with AD.

POS1247 THE EFFECT OF IMMUNOSUPPRESSIVE AGENTS ON ANTIBODY FORMATION AFTER COVID-19 VACCINATION IN RHEUMATOID ARTHRITIS PATIENTS

Background

There is still controversy about the efficacy of COVID-19 vaccination and its extent in lowering immunogenicity of Rheumatoid Arthritis (RA) patients. The guideline in whether immunosuppressive agents need to be discontinued before the vaccination is continuously updated because it is considered to lower immunogenicity. Furthermore, there is great discussion on the effectiveness of the COVID-19 booster vaccine and interest in antibody generation in different types of vaccine, as in South Korea there are many patients who were prescribed the mRNA booster vaccine after two doses of ChAdOx1-S nCoV-19 vaccine.

Objectives

Thus, we investigated the differences of antibody production between patients who received only two doses of ChAdOx1-S nCoV-19 and those who received the mRNA booster vaccine. Also, antibody production under different types of immunosuppressive agents was analyzed.

Methods

From October 14, 2021 to January 21, 2022 at a tertiary referral center, two patient groups diagnosed with RA were studied prospectively; one group that completed 1st and 2nd doses of ChAdOx1-S nCoV-19 vaccine, second group that completed mRNA booster vaccine as well as two doses of ChAdOx1-S nCoV-19 vaccine. SARS-CoV-2 antibody testing on the semiquantitative anti-SARS-CoV-2 S enzyme immunoassay was done, and differences in antibody titers were analyzed in patients who received different immunosuppressive agents such as csDMARD, TNF inhibitor, JAK inhibitor, Tocilizumab, Abatacept and Corticosteroid. Statistical analysis with a multivariate logistic regression model was performed.

Results

In a total of 261 patients, 153 patients had completed two doses of ChAdOx1-S nCoV-19, 108 patients had completed third mRNA booster vaccine. Anti-SARS-CoV-2 RBD antibody positive rate (titer>0.8U/mL) was 97%(149/153) and 99%(107/108) respectively, and only 5 patients showed negative result. In the aspect of high antibody titer(>250U/mL), which is the upper limit of the RBD antibody immunoassay, the result showed rate of 31% (47/153) in the non-booster group and 94%(102/108) in the booster group respectively.

Among the different immunosuppressive agents and other clinical aspects, multivariate analysis revealed that corticosteroid use (OR 0.91; 95% CI: 0.86-0.98), older age(OR 4.33; 95% CI: 1.34-13.91), and male gender(OR 0.35; 95% CI 0.16-0.75) were significantly associated with low rate of high antibody titer.

Furthermore, out of 14 patients who underwent antibody test twice before and after the mRNA booster vaccine, other than four patients who already showed high titer of >250U/mL before the mRNA booster vaccine, 10 patients showed an increase in titer after the booster vaccine and 7 patients were acquired high titer of >250U/mL.

Figure 1.

Anti-SARS-CoV RBD antibody titer of two groups

Table 1.

Analysis of immunosuppressive agents and other clinical aspects for high antibody titer(>250U/mL) after two doses of ChAdOx1-S nCoV-19

Univariate analysisMultivariate analysisParameterOR95% CIp valueOR95% CIp valueClinical features Age0.9170.860-0.9780.0080.9170.857-0.9810.012 Sex3.6741.206-11.1910.0224.3301.348-13.9120.014 DAS 281.1440.670-1.9500.622 Duration0.9300.830-1.0430.214Medications csDMARD1.2730.639-2.5331.273 TNF inhibitor2.2110.795-6.1450.128 JAK inhibitor0.6650.275-1.6070.365 Abatacept0.3680.038-3.6020.391 Tocilizumab1.2640.438-3.6480.665 Corticosteroid0.4720.235-0.9490.0350.3490.163-0.7480.007Medication dose Methotrexate0.9930.919-1.0720.855 Corticosteroid0.8490.719-1.0030.054

Conclusion

Anti-SARS-CoV-2 RBD antibody positive rate was 97% or more regardless of the mRNA booster vaccination. However, patients who received the mRNA booster vaccine after two doses of ChAdOx1-S nCoV-19 vaccine showed high antibody titer (>250U/mL) three times more than those who did not receive the booster shot.

Our findings also showed that corticosteroid use, old age, and male gender is significantly associated with low rate of acquiring high antibody titer.

Disclosure of Interests

None declared

POS0762 LONG-TERM RENAL OUTCOMES OF PATIENTS WITH NON-PROLIFERATIVE LUPUS NEPHRITIS

Background

Although proliferative (class III or IV) lupus nephritis (LN) is the most common finding in the classification of LN, pure membranous (class V) or mesangial (class I or II) LN can occur as a form of LN. Even though non-proliferative LN (class I, II, or V) is a less severe form with good outcomes, data on long-term renal prognosis are limited.

Objectives

This study investigated the long-term outcomes and prognostic factors in non-proliferative LN.

Methods

We retrospectively reviewed the medical records of patients with systemic lupus erythematosus who were diagnosed with LN class I, II, V or II+IV by kidney biopsy between 1997 and 2021 at a tertiary referral center. Clinical and laboratory data were compared between patients with and without poor renal outcomes. Poor renal outcome was defined as an estimated glomerular filtration rate (eGFR) of < 60 mL/min/1.73 m2 or death due to renal cause. Univariate and multivariate analyses were performed with the Cox proportional hazard model to identify the factors associated with poor renal outcomes.

Results

We included 71 patients with non-proliferative LN (4: class I; 17: class II; 48: class V, 17; 2: class II+V). Median follow-up duration was 103 months (interquartile range 27–185) and the overall rate of poor renal outcomes at last follow-up was 29% (21/71), including end-stage renal disease (n=2) and renal death (n=1).

Univariate analysis indicated that older age (HR 1.05; 95% CI: 1.00–1.09), low eGFR (HR 0.97; 95% CI: 0.95–0.99) and failure to reach complete remission at 6 months (HR 0.332; 95% CI: 0.12–0.92) were significantly associated with poor renal outcomes. Multivariate analysis revealed that low eGFR at 6 months (HR 0.97; 95% CI: 0.95–0.99) was significantly associated with poor renal outcomes.

Figure 1.

Renal outcomes at last follow up

eGFR, estimated glomerular filtration rate (ml/min/1.73m2)

Table 1.

Univariate and multivariate Cox proportional hazard regression analyses of the factor associated with poor renal outcomes

ParameterUnivariate analysisMultivariate analysisHR95% CIp valueHR95% CIp valueClinical features Age1.0461.003-1.0910.0361.0020.960-1.0470.921 Sex1.6540.375-7.2980.506 SLEDAI1.0360.965-1.1120.327 Extra renal SLEDAI1.0380.971-1.110.272Renal profiles eGFR at LN diagnosis0.9930.976-1.0110.456 Proteinuria at LN diagnosis1.0001.000-1.0000.444 > 1g/24 hours0.6690.243-1.8410.437  > 3g/24 hours0.6240.229-1.6990.356 eGFR at 6M0.9670.948-0.9860.0010.9680.948-0.9880.002 eGFR at 12M0.9640.947-0.9810.000 Complete remission at 6M0.3320.119-0.9240.0350.5530.179-1.7070.303 Complete remission at 12M0.6670.232-1.9140.451 Transformation1.2460.423-0.7010.692Laboratory data Anti-dsDNA1.0010.999-1.0030.196 C31.0201.000-1.0410.051 C41.0270.969-1.0890.367 Albumin1.1800.661-2.1090.576ClassificationaClass I0.8020.102-6.3030.834Class II1.2980.412-4.0880.656Class V0.8870.308-2.5570.824Class II+V0.0480.000-16850.837Medicationsb ACEi/ARB1.6520.603-4.5280.329 Hydroxychloroquine1.3260.414-4.2420.635 Corticosteroid1.1860.154-9.1080.870 CNI2.4390.464-12.8240.292 MMF3.7880.959-14.9650.057  　 AZA0.5890.133-2.6110.486

a LN classifications were based on the International Society of Pathology/Renal Pathology Society (ISN/RPS) classification.

b Medications maintained at least one year since Lupus Nephritis diagnosis.

HR, hazard ratio; 95% CI, 95% confidence interval; SLEDAI, systemic lupus erythematosus disease activity index; eGFR, estimated glomerular filtration rate; LN, lupus nephritis; anti-dsDNA, anti-double strand DNA; C3/C4; complement 3/4; ACEi, angiotensin-converting enzyme inhibitor; ARB, angiotensin receptor blocker; CNI, carcineurin inhibitor; MMF, mycophenolate mofetil; AZA, azathioprine.

Conclusion

Poor renal outcomes occurred in approximately 30% of patients with non-proliferative LN (class I, II or V) after long-term follow-up.

Our findings suggest that more active management may be needed for non-proliferative LN, particularly in patients with low eGFR at 6 months.

Disclosure of Interests

None declared

Past the Precipice? Projected Coral Habitability Under Global Heating

Coral reefs are rapidly declining due to local environmental degradation and global climate change. In particular, corals are vulnerable to ocean heating. Anomalously hot sea surface temperatures (SSTs) create conditions for severe bleaching or direct thermal death. We use SST observations and CMIP6 model SST to project thermal conditions at reef locations at a resolution of 1 km, a 16-fold improvement over prior studies, under four climate emissions scenarios. We use a novel statistical downscaling method which is significantly more skillful than the standard method, especially at near-coastal pixels where many reefs are found. For each location we present projections of thermal departure (TD, the date after which a location with steadily increasing heat exceeds a given thermal metric) for severe bleaching recurs every 5 years (TD5Y) and every 10 years (TD10Y), accounting for a range of post-bleaching reef recovery/degradation. As of 2021, we find that over 91% and 79% of 1 km² reefs have exceeded TD10Y and TD5Y, respectively, suggesting that widespread long-term coral degradation is no longer avoidable. We project 99% of 1 km² reefs to exceed TD5Y by 2034, 2036, and 2040 under SSP5-8.5, SSP3-7.0, and SSP2-4.5 respectively. We project that 2%-5% of reef locations remain below TD5Y at 1.5°C of mean global heating, but 0% remain at 2.0°C. These results demonstrate the importance of further improving ecological projection capacity for climate-vulnerable marine and terrestrial species and ecosystems, including identifying refugia and guiding conservation efforts. Ultimately, saving coral reefs will require rapidly reducing and eliminating greenhouse gas emissions.

Added value of enhanced CT on LR-3 and LR-4 observation of Gd-EOB-DTPA MRI for the diagnosis of HCC: are CT and MR washout features interchangeable?

OBJECTIVE

To characterize the use of portal venous or delayed phase CT as an alternative to estimate washout for the non-invasive diagnosis of hepatocellular carcinoma (HCC) on gadoxetic acid-enhanced MRI in combination with other features.

METHODS

This retrospective study included 226 observations (n = 162 patients) at high risk for HCC imaged with gadoxetic acid-enhanced MRI and enhanced liver CT between March 2015 and March 2018. Two radiologists independently evaluated two sets of images and assigned the final Liver Imaging Reporting and Data System (LI-RADS) categories by consensus using gadoxetic acid-enhanced MRI. LR-1, LR-2, LR-5, and LR-M were excluded from the study.The observations were divided using different criteria for washout: hypointensity on the portal venous phase (PVP) at MRI (criteria 1), hypointensity on PVP at MRI and/or hypoattenuation on the PVP/delayed phase at dynamic CT (criteria 2), and hypointensity on the PVP and/or hepatobiliary phase at MRI (criteria 3). The sensitivity, specificity, and accuracy for the diagnosis of HCC were analyzed for each criterion.

RESULTS

Using gadoxetic acid-enhanced, 226 lesions were diagnosed as LR-3 or LR-4 by LI-RADS. Among them, 98 and 152 had "washout" at criteria 1 and 2, respectively. For the diagnosis of HCC, criteria 2 and 3 showed significantly higher sensitivities (67.3 and 92.5%, respectively) compared with criteria 1 (35.5%) (p < 0.001). The specificity of criteria 3 (13%) was significantly lower than those of criteria 1 and 2 (40.7% and 38.4%, respectively, p < 0.001). The specificities between criteria 1 and 2 were not statistically different (p = 0.427).

CONCLUSION

Although the LI-RADS lexicon does not permit the interchange of image features among various image modalities, the sensitivity of HCC diagnosis could be improved without any decrease in specificity by adding CT image washout features.

ADVANCES IN KNOWLEDGE

Although the LI-RADS lexicon does not permit the interchange of image features among various image modalities, complementary use of dynamic CT in LR-3 or LR-4 categories on the basis of gadoxetic acid-enhanced MRI may contribute to major imaging feature.

Horizontal mtDNA transfer between cells is common during mouse development

Cells transmit their genomes vertically to daughter cells during cell divisions. Here, we demonstrate the occurrence and extent of horizontal mitochondrial (mt)DNA acquisition between cells that are not in a parent-offspring relationship. Extensive single-cell sequencing from various tissues and organs of adult chimeric mice composed of cells carrying distinct mtDNA haplotypes showed that a substantial fraction of individual cardiomyocytes, neurons, glia, intestinal, and spleen cells captured donor mtDNA at high levels. In addition, chimeras composed of cells with wild-type and mutant mtDNA exhibited increased trafficking of wild-type mtDNA to mutant cells, suggesting that horizontal mtDNA transfer may be a compensatory mechanism to restore compromised mitochondrial function. These findings establish the groundwork for further investigations to identify mtDNA donor cells and mechanisms of transfer that could be critical to the development of novel gene therapies.

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Individual cells in adult mouse chimeras acquire donor mtDNA horizontally

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Significant percentage of cardiomyocytes, neurons, and glia were heteroplasmic

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Donor mtDNA heteroplasmy in these cells can reach up to 50%

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Pathogenic mtDNA mutations may potentiate horizontal acquisition of wild-type mtDNA

Haploidy in somatic cells is induced by mature oocytes in mice

Haploidy is naturally observed in gametes; however, attempts of experimentally inducing haploidy in somatic cells have not been successful. Here, we demonstrate that the replacement of meiotic spindles in mature metaphases II (MII) arrested oocytes with nuclei of somatic cells in the G0/G1 stage of cell cycle results in the formation of de novo spindles consisting of somatic homologous chromosomes comprising of single chromatids. Fertilization of such oocytes with sperm triggers the extrusion of one set of homologous chromosomes into the pseudo-polar body (PPB), resulting in a zygote with haploid somatic and sperm pronuclei (PN). Upon culture, 18% of somatic-sperm zygotes reach the blastocyst stage, and 16% of them possess heterozygous diploid genomes consisting of somatic haploid and sperm homologs across all chromosomes. We also generate embryonic stem cells and live offspring from somatic-sperm embryos. Our finding may offer an alternative strategy for generating oocytes carrying somatic genomes.

Efficient hepatic differentiation and regeneration potential under xeno-free conditions using mass-producible amnion-derived mesenchymal stem cells

BACKGROUND

Amnion-derived mesenchymal stem cells (AM-MSCs) are an attractive source of stem cell therapy for patients with irreversible liver disease. However, there are obstacles to their use due to low efficiency and xeno-contamination for hepatic differentiation.

METHODS

We established an efficient protocol for differentiating AM-MSCs into hepatic progenitor cells (HPCs) by analyzing transcriptome-sequencing data. Furthermore, to generate the xeno-free conditioned differentiation protocol, we replaced fetal bovine serum (FBS) with polyvinyl alcohol (PVA). We investigated the hepatocyte functions with the expression of mRNA and protein, secretion of albumin, and activity of CYP3A4. Finally, to test the transplantable potential of HPCs, we transferred AM-MSCs along with hepatic progenitors after differentiated days 11, 12, and 13 based on the expression of hepatocyte-related genes and mitochondrial function. Further, we established a mouse model of acute liver failure using a thioacetamide (TAA) and cyclophosphamide monohydrate (CTX) and transplanted AM-HPCs in the mouse model through splenic injection.

RESULTS

We analyzed gene expression from RNA sequencing data in AM-MSCs and detected downregulation of hepatic development-associated genes including GATA6, KIT, AFP, c-MET, FGF2, EGF, and c-JUN, and upregulation of GSK3. Based on this result, we established an efficient hepatic differentiation protocol using the GSK3 inhibitor, CHIR99021. Replacing FBS with PVA resulted in improved differentiation ability, such as upregulation of hepatic maturation markers. The differentiated hepatocyte-like cells (HLCs) not only synthesized and secreted albumin, but also metabolized drugs by the CYP3A4 enzyme. The best time for translation of AM-HPCs was 12 days from the start of differentiation. When the AM-HPCs were transplanted into the liver failure mouse model, they settled in the damaged livers and differentiated into hepatocytes.

CONCLUSION

This study offers an efficient and xeno-free conditioned hepatic differentiation protocol and shows that AM-HPCs could be used as transplantable therapeutic materials. Thus, we suggest that AM-MSC-derived HPCs are promising cells for treating liver disease.

Mitochondrial gene mutations in pediatric septic shock

BACKGROUND

There has been a growing interest in the association between mitochondrial dysfunction and sepsis. However, most studies have focused on mitochondrial structural damage, functional aspects, or the clinical phenotypes in sepsis. The purpose of this study was to evaluate mitochondrial DNA (mtDNA) gene mutations in critically ill pediatric patients with septic shock.

METHOD

Thirteen patients with severe sepsis or septic shock admitted to the pediatric intensive care unit (PICU) of a tertiary children's hospital were enrolled in this prospective observational study. Clinical data from electronic medical records were obtained. Whole-blood samples were collected within 24 h of PICU admission to perform PBMC isolation, mtDNA extraction, and mtDNA sequencing using next-generation sequencing.

RESULTS

mtDNA sequencing revealed mutations in 9 of the 13 patients, presenting 27 point mutations overall, with 15 (55.6%) located in the locus related to adenosine triphosphate production and superoxide metabolism, including electron transport.

CONCLUSION

In this pilot study, significant numbers of mtDNA point mutations were detected in critically ill pediatric patients with septic shock. These mutations could provide promising evidence for mitochondrial dysfunction in sepsis and a basis for further large-scale studies.

IMPACT

This study is the first to examine mitochondrial DNA mutations in pediatric patients with septic shock using next-generation sequencing. A high frequency of mitochondrial DNA mutations was detected in these patients indicating an association with septic shock. This pilot study may provide a potential explanation for the association between mitochondrial dysfunction and septic shock on a genetic basis.

Effect of negative-pressure wound therapy on wound complications in obese women after caesarean birth: a systematic review and meta-analysis

BACKGROUND

Obesity is associated with increased surgical-site infection (SSI) following caesarean section (CS).

OBJECTIVE

To summarise the evidence on the effectiveness of negative-pressure wound therapy (NPWT) for preventing SSI and other wound complications in obese women after CS.

SEARCH STRATEGY

MEDLINE, Embase, CINAHL, Cochrane CENTRAL databases and ClinicalTrials.gov were systematically searched in March 2021.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of NPWT compared with standard dressings after CS birth.

DATA COLLECTION AND ANALYSIS

Pooled effect sizes were calculated using either fixed or random effects models based on heterogeneity. The Cochrane risk of bias and Grading of Recommendations Assessment, Development and Evaluation tools were used to assess the quality of studies and overall quality of evidence.

MAIN RESULTS

Ten RCTs with 5583 patients were included; studies were published between 2012 and 2021. Nine RCTs with 5529 patients were pooled for the outcome SSI. Meta-analysis results suggest a significant difference favouring the NPWT group (relative risk [RR] 0.79, 95% CI 0.65-0.95, P < 0.01), indicating an absolute risk reduction of 1.8% among those receiving NPWT compared with usual care. The risk of blistering in the NPWT group was significantly higher (RR 4.13, 95% CI 1.53-11.18, P = 0.005). All studies had high risk of bias relative to blinding of personnel/participants. Only 40% of studies reported blinding of outcome assessments and 50% had incomplete outcome data.

CONCLUSIONS

The decision to use NPWT should be considered both in terms of its potential benefits and its limitations.

TWEETABLE ABSTRACT

NPWT was associated with fewer SSI in women following CS birth but was not effective in reducing other wound complications.

Mitochondrial DNA Haplogroup Related to the Prevalence of Helicobacter pylori

Mitochondria are essential organelles that are not only responsible for energy production but are also involved in cell metabolism, calcium homeostasis, and apoptosis. Targeting mitochondria is a key strategy for bacteria to subvert host cells' physiology and promote infection. Helicobacter (H.) pylori targets mitochondria directly. However, mitochondrial genome (mtDNA) polymorphism (haplogroup) is not yet considered an important factor for H. pylori infection. Here, we clarified the association of mitochondrial haplogroups with H. pylori prevalence and the ability to perform damage. Seven mtDNA haplogroups were identified among 28 H. pylori-positive subjects. Haplogroup B was present at a higher frequency and haplotype D at a lower one in the H. pylori population than in that of the H. pylori-negative one. The fibroblasts carrying high-frequency haplogroup displayed a higher apoptotic rate and diminished mitochondrial respiration following H. pylori infection. mtDNA mutations were accumulated more in the H. pylori-positive population than in that of the H. pylori-negative one in old age. Among the mutations, 57% were located in RNA genes or nonsynonymous protein-coding regions in the H. pylori-positive population, while 35% were in the H. pylori-negative one. We concluded that gastric disease caused by Helicobacter virulence could be associated with haplogroups and mtDNA mutations.

Germline transmission of donor, maternal and paternal mtDNA in primates

STUDY QUESTION

What are the long-term developmental, reproductive and genetic consequences of mitochondrial replacement therapy (MRT) in primates?

SUMMARY ANSWER

Longitudinal investigation of MRT rhesus macaques (Macaca mulatta) generated with donor mtDNA that is exceedingly distant from the original maternal counterpart suggest that their growth, general health and fertility is unremarkable and similar to controls.

WHAT IS KNOWN ALREADY

Mitochondrial gene mutations contribute to a diverse range of incurable human disorders. MRT via spindle transfer in oocytes was developed and proposed to prevent transmission of pathogenic mtDNA mutations from mothers to children.

STUDY DESIGN, SIZE, DURATION

The study provides longitudinal studies on general health, fertility as well as transmission and segregation of parental mtDNA haplotypes to various tissues and organs in five adult MRT rhesus macaques and their offspring.

PARTICIPANTS/MATERIALS, SETTING, METHODS

MRT was achieved by spindle transfer between metaphase II oocytes from genetically divergent rhesus macaque populations. After fertilization of oocytes with sperm, heteroplasmic zygotes contained an unequal mixture of three parental genomes, i.e. donor (≥97%), maternal (≤3%), and paternal (≤0.1%) mitochondrial (mt)DNA. MRT monkeys were grown to adulthood and their development and general health was regularly monitored. Reproductive fitness of male and female MRT macaques was evaluated by time-mated breeding and production of live offspring. The relative contribution of donor, maternal, and paternal mtDNA was measured by whole mitochondrial genome sequencing in all organs and tissues of MRT animals and their offspring.

MAIN RESULTS AND THE ROLE OF CHANCE

Both male and female MRT rhesus macaques containing unequal mixture of three parental genomes, i.e. donor (≥97%), maternal (≤3%), and paternal (≤0.1%) mtDNA reached healthy adulthood, were fertile and most animals stably maintained the initial ratio of parental mtDNA heteroplasmy and donor mtDNA was transmitted from females to offspring. However, in one monkey out of four analyzed, initially negligible maternal mtDNA heteroplasmy levels increased substantially up to 17% in selected internal tissues and organs. In addition, two monkeys showed paternal mtDNA contribution up to 33% in selected internal tissues and organs.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Conclusions in this study were made on a relatively low number of MRT monkeys, and on only one F1 (first generation) female. In addition, monkey MRT involved two wildtype mtDNA haplotypes, but not disease-relevant variants. Clinical trials on children born after MRT will be required to fully determine safety and efficacy of MRT for humans.

WIDER IMPLICATIONS OF THE FINDINGS

Our data show that MRT is compatible with normal postnatal development including overall health and reproductive fitness in nonhuman primates without any detected adverse effects. 'Mismatched' donor mtDNA in MRT animals even from the genetically distant mtDNA haplotypes did not cause secondary mitochondrial dysfunction. However, carry-over maternal or paternal mtDNA contributions increased substantially in selected internal tissues / organs of some MRT animals implying the possibility of mtDNA mutation recurrence.

STUDY FUNDING/COMPETING INTEREST(S)

This work has been funded by the grants from the Burroughs Wellcome Fund, the National Institutes of Health (RO1AG062459 and P51 OD011092), National Research Foundation of Korea (2018R1D1A1B07043216) and Oregon Health & Science University institutional funds. The authors declare no competing interests.

Optomechanical crystals for spatial sensing of submicron sized particles

Optomechanical crystal cavities (OMC) have rich perspectives for detecting and indirectly analysing biological particles, such as proteins, bacteria and viruses. In this work we demonstrate the working principle of OMCs operating under ambient conditions as a sensor of submicrometer particles by optically monitoring the frequency shift of thermally activated mechanical modes. The resonator has been specifically designed so that the cavity region supports a particular family of low modal-volume mechanical modes, commonly known as -pinch modes-. These involve the oscillation of only a couple of adjacent cavity cells that are relatively insensitive to perturbations in other parts of the resonator. The eigenfrequency of these modes decreases as the deformation is localized closer to the centre of the resonator. Thus, by identifying specific modes that undergo a frequency shift that amply exceeds the mechanical linewidth, it is possible to infer if there are particles deposited on the resonator, how many are there and their approximate position within the cavity region. OMCs have rich perspectives for detecting and indirectly analysing biological particles, such as proteins, viruses and bacteria.

A review for the definition of the concept and symptoms of Hwa-Byung

Introduction

Hwa-Byung is a unique syndrome based on social-cultural background of South Korea. However, the definition of Hwa-Byung has not been established. For example, Hwa-Byung Diagnostic Interview Schedule(Kim, Kwon, Lee & Park, 2004) and Hwa-Byung Scale(Kwon et al., 2008) that are generally used in clinical practices defined Hwa-Byung differently. According to this, there is a slight difference in the symptoms that are measured.

Objectives

The purpose of our study is to establish the concept and symptoms of Hwa-Byung.

Methods

First, we review DSM-4, previous literatures and concept of Hwa-Byung in assessment tools. Through this, core features and characteristic symptoms are consisted. Second, a concept of Hwa-Byung that this study constructed is reviewed by clinical psychologists and Korean oriental psychiatrists. Finally, concepts and symptoms are defined.

Results

Comprehensive definition of Hwa-Byung is established. Hwa-Byung was identified as a syndrome with symptoms that exploded in the form of anger because emotions such as anger could not be resolved. psychological symptoms include resentment, the baggage of mind, or a representative symptom of han. And physical symptoms include feeling heavy, heat, rush, lumps in the neck or chest. Finally, these physical and psychological symptoms are associated with distinct stressful events.

Conclusions

Our study defined the concept and categorized for physical and emotional symptoms of Hwa-Byung. This result suggests that it can contribute to the development and revision of the Hwa-Byung assessment tools.

Disclosure

No significant relationships.

De Novo Development of mtDNA Deletion Due to Decreased POLG and SSBP1 Expression in Humans

Defects in the mitochondrial genome (mitochondrial DNA (mtDNA)) are associated with both congenital and acquired disorders in humans. Nuclear-encoded DNA polymerase subunit gamma (POLG) plays an important role in mtDNA replication, and proofreading and mutations in POLG have been linked with increased mtDNA deletions. SSBP1 is also a crucial gene for mtDNA replication. Here, we describe a patient diagnosed with Pearson syndrome with large mtDNA deletions that were not detected in the somatic cells of the mother. Exome sequencing was used to evaluate the nuclear factors associated with the patient and his family, which revealed a paternal POLG mutation (c.868C > T) and a maternal SSBP1 mutation (c.320G > A). The patient showed lower POLG and SSBP1 expression than his healthy brothers and the general population of a similar age. Notably, c.868C in the wild-type allele was highly methylated in the patient compared to the same site in both his healthy brothers. These results suggest that the co- deficient expression of POLG and SSBP1 genes could contribute to the development of mtDNA deletion.

Structure of oxidized pyrrolidone carboxypeptidase from Fervidobacterium islandicum AW-1 reveals unique structural features for thermostability and keratinolysis

Pyrrolidone carboxypeptidases (Pcps) (E.C. 3.4.19.3) can cleave the peptide bond adjacent to pyro-glutamic acid (pGlu), an N-terminal modification observed in some proteins that provides protection against common proteases. Pcp derived from extremely thermophilic Fervidobacterium islandicum AW-1 (FiPcp), that belongs to the cysteine protease family, is involved in keratin utilization under stress conditions. Although an irreversible oxidative modification of active cysteine to its sulfonic acid derivative (Cys-SO₃H) renders the enzyme inactive, the molecular details for the sulfonic acid modification in inactive Pcp remain unclear. Here, we determined the crystal structure of FiPcp at 1.85 Å, revealing the oxidized form of cysteine sulfonic acid (C156-SO₃H) in the catalytic triad (His-Cys-Glu), which participates in the hydrolysis of pGlu residue containing peptide bond. The three oxygen atoms of cysteine sulfonic acid were stabilized by hydrogen bonds with H180, carbonyl backbone of Q83, and water molecules, resulting in inactivation of FiPcp. Furthermore, FiPcp demonstrated a unique ¹³⁹KKKK¹⁴² motif involved in inter-subunit electrostatic interactions whose mutation significantly affects the thermostability of tetrameric FiPcp. Thus, our high-resolution structure of the first inactive FiPcp with irreversible oxidative modification of active cysteine provides not only the molecular basis of the redox-dependent catalysis of Pcp, but also the structural features of its thermostability.

The Rho-associated kinase inhibitor fasudil can replace Y-27632 for use in human pluripotent stem cell research

Poor survival of human pluripotent stem cells (hPSCs) following freezing, thawing, or passaging hinders the maintenance and differentiation of stem cells. Rho-associated kinases (ROCKs) play a crucial role in hPSC survival. To date, a typical ROCK inhibitor, Y-27632, has been the primary agent used in hPSC research. Here, we report that another ROCK inhibitor, fasudil, can be used as an alternative and is cheaper than Y-27632. It increased hPSC growth following thawing and passaging, like Y-27632, and did not affect pluripotency, differentiation ability, and chromosome integrity. Furthermore, fasudil promoted retinal pigment epithelium (RPE) differentiation and the survival of neural crest cells (NCCs) during differentiation. It was also useful for single-cell passaging of hPSCs and during aggregation. These findings suggest that fasudil can replace Y-27632 for use in stem research.

Mitochondrial genome mutations in mesenchymal stem cells derived from human dental induced pluripotent stem cells

Ethical and safety issues have rendered mesenchymal stem cells (MSCs) popular candidates in regenerative medicine, but their therapeutic capacity is lower than that of induced pluripotent stem cells (iPSCs). This study compared original, dental tissue-derived MSCs with re-differentiated MSCs from iPSCs (iPS-MSCs). CD marker expression in iPS-MSCs was similar to original MSCs. iPS-MSCs expressed higher in pluripotent genes, but lower levels in mesodermal genes than MSCs. In addition, iPS-MSCs did not form teratomas. All iPSCs carried mtDNA mutations; some shared with original MSCs and others not previously detected therein. Shared mutations were synonymous, while novel mutations were non-synonymous or located on RNA-encoding genes. iPS-MSCs also harbored mtDNA mutations transmitted from iPSCs. Selected iPS-MSCs displayed lower mitochondrial respiration than original MSCs. In conclusion, screening for mtDNA mutations in iPSC lines for iPS-MSCs can identify mutation-free cell lines for therapeutic applications. [BMB Reports 2019; 52(12): 689-694].

Deleterious mtDNA mutations are common in mature oocytes

Heritable mitochondrial DNA (mtDNA) mutations are common, yet only a few recurring pathogenic mtDNA variants account for the majority of known familial cases in humans. Purifying selection in the female germline is thought to be responsible for the elimination of most harmful mtDNA mutations during oogenesis. Here we show that deleterious mtDNA mutations are abundant in ovulated mature mouse oocytes and preimplantation embryos recovered from PolG mutator females but not in their live offspring. This implies that purifying selection acts not in the maternal germline per se, but during post-implantation development. We further show that oocyte mtDNA mutations can be captured and stably maintained in embryonic stem cells and then reintroduced into chimeras, thereby allowing examination of the effects of specific mutations on fetal and postnatal development.

Identification of keratinases from Fervidobacterium islandicum AW-1 using dynamic gene expression profiling

Keratin degradation is of great interest for converting agro‐industrial waste into bioactive peptides and is directly relevant for understanding the pathogenesis of superficial infections caused by dermatophytes. However, the mechanism of this process remains unclear. Here, we obtained the complete genome sequence of a feather‐degrading, extremely thermophilic bacterium, Fervidobacterium islandicum AW‐1 and performed bioinformatics‐based functional annotation. Reverse transcription PCR revealed that 57 putative protease‐encoding genes were differentially expressed in substrate‐dependent manners. Consequently, 16 candidate genes were highly expressed under starvation conditions, when keratin degradation begun. Subsequently, the dynamic expression profiles of these 16 selected genes in response to feathers, as determined via quantitative real‐time PCR, suggested that they included four metalloproteases and two peptidases including an ATP‐dependent serine protease, all of which might act as key players in feather decomposition. Furthermore, in vitro keratinolytic assays supported the notion that recombinant enzymes enhanced the decomposition of feathers in the presence of cell extracts. Therefore, our genome‐based systematic and dynamic expression profiling demonstrated that these identified metalloproteases together with two additional peptidases might be primarily associated with the decomposition of native feathers, suggesting that keratin degradation can be achieved via non‐canonical catalysis of several membrane‐associated metalloproteases in cooperation with cytosolic proteases.

Stem cells and reproduction

Reproductive biotechnology has developed rapidly and is now able to overcome many birth difficulties due to infertility or the transmission of genetic diseases. Here we introduce the next generation of assisted reproductive technologies (ART), such as mitochondrial replacement technique (MRT) or genetic correction in eggs with micromanipulation. Further, we suggest that the transmission of genetic information from somatic cells to subsequent generations without gametes should be useful for people who suffer from infertility or genetic diseases. Pluripotent stem cells (PSCs) can be converted into germ cells such as sperm or oocytes in the laboratory. Notably, germ cells derived from nuclear transfer embryonic stem cells (NT-ESCs) or induced pluripotent stem cells (iPSCs) inherit the full parental genome. The most important issue in this technique is the generation of a haploid chromosome from diploid somatic cells. We hereby examine current science and limitations underpinning these important developments and provide recommendations for moving forward.

Author Correction: Mitochondrial replacement in human oocytes carrying pathogenic mitochondrial DNA mutations

Change history In this Letter, there are several errors regarding the assignments of mtDNA haplotypes for a subset of egg donors from our study. These errors have not been corrected online.

Abstract P4-04-10: Genomic profiling of multifocal breast cancer reveals inter-lesion heterogeneity

Introduction: Multifocal breast cancers are common, and tend to show more aggressive clinical features than unifocal breast cancers. While each foci of multifocal breast cancers with similar histology shares the same hormone and ERBB2 receptor status in most cases, substantial genomic differences among lesions have been reported. We aimed to investigate the potential genomic differences between multifocal breast cancer lesions.

Materials and methods: Twenty-one patients with multifocal breast cancer documented in the resection specimen were included. We selected two lesions with the same histology from each of these 21 patients. Capture-based targeted next generation sequencing was performed using a cancer gene panel consisting of 170 genes for single nucleotide variants (SNV) and small insertions/deletions (Indel), and copy number alterations.

Results: The most frequent mutation was TP53 (38.1%), followed by PIK3CA (28.6%). Pathogenic mutations (SNV and Indel) were detected in 13 of 21 patients, of whom 11 shared oncogenic variants in the two lesions. The remaining two patients had different mutation results in TP53 and PIK3CA, respectively. Genomic heterogeneity of copy number alteration was observed in 6 (28.6%) of 21 patients, including difference of FGFR1 status in two patients and difference of FGFR2 status in one patient.

Conclusion: Despite similar histologic features of multifocal tumors, genomic inter-lesion heterogeneity was identified in about one-fourth of patients. The spatial genomic heterogeneity in multifocal breast cancers needs to be considered in representative sampling and molecular tests for personalized medicine.

Citation Format: Ahn S, Kim HJ, Kang E, Kim E-K, Kim SH, Kim JH, Kim IA, Park SY. Genomic profiling of multifocal breast cancer reveals inter-lesion heterogeneity [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-04-10.

Abstract P4-03-10: Identifying germline APOBEC3B deletion using hereditary cancer panel in Korean patients with operable breast cancer

Background: APOBEC3B is a cytosine deaminase implicated in host immune defense to virus and mutagenesis in cancer. Germline APOBEC3B deletion is known as risk factors for breast cancer with hypermutation and immune activation from previous database-based studies. This study was aimed to evaluate the incidence of germline APOBEC3B deletion in Korean patients with operable breast cancer.

Method: The copy number variants of germline APOBEC3B deletion was analyzed from leukocyte DNA of 103 breast cancer patients whose bloods were collected in 2009 for pharmacogenomic study at Seoul National University Bundang Hospital. Hybrid-capture based next-generation sequencing panel targeting 53 hereditary cancer genes were used. We also measured tumor infiltrating lymphocytes (TILs) and programmed cell death-ligand 1 (PD-L1) expression in tumor or immune cell with a rabbit monoclonal antibody (E1L3N).

Results: Median age of breast cancer diagnosis was 46 (25-72). In APOBEC3B deletion analysis, 10 (9.7%), 36 (35.0%), and 57 (55.3%) patients were identified as two-copy deletion (A3Bdel/del), one-one copy deletion (A3Bdel/wt) and no deletion (A3Bwt/wt), respectively. In non-APOBEC3B analysis, 9 (8.7%) patients were identified as pathogenic variant: RAD51D(n=1), GJB2(n=1), BRCA1(n=1), BRCA2 (n=2), ATM(n=1), USH2A(n=1), RET(n=1), BARD1(n=1). We observed no significant association between germline APOBEC3B deletion with any clinicopathologic features of breast cancer such as age, family history of cancer, and bilateral breast cancer. Triple-negative subtype was associated with A3Bwt/wt Tumors (35.1% in A3Bwt/wt vs. 5.6% in A3Bdel/wt vs20% in A3Bdel/del; P=0.018). After a median follow-up time of 92.8 months, APOBEC3B deletion was not predictive of recurrence or survival. In patients with sufficient tumor samples for the assessment of TIL (n=63) and PD-1 (n=71), A3Bdel/del tumor was associated with higher TILs (&gt;10%) than other tumor types (6/7 patients in A3Bdel/del vs. 13/24 in A3Bdel/wt vs. 15/32 in A3Bwt/wt: Fisher's exact test in A3Bdel/del, P=0.029). However, PD-L1 expression was not associated with APOBEC3B deletion status (1/7 patients &gt;1% PD-L1 in A3Bdel/del vs. 4/26 in A3Bdel/wt vs. 8/38 in A3Bwt/wt: P=0.901).

Germline APOBEC3B deletion and TILs (n=63) TIL (0-10%)TIL (&gt;10%)TotalA3B(wt/wt)17 (53.1%)15 (46.9%)32A3B(del/wt)11 (45.8%)13 (54.2%)24A3B(del/del)1 (14.3%)6 (85.7%)7

Conclusion: We identified germline APOBEC3B deletion in 9.7% of Korean patients with operable breast cancer. The relationship between A3Bdel/del tumor and high TILs suggests that these tumors might be potential candidates for future immunotherapy.

Citation Format: Kim SH, Koung Jin S, Kim YJ, Ahn S, Park SY, Chae SM, Kang E, Kim E-K, Kim IA, Kim JH. Identifying germline APOBEC3B deletion using hereditary cancer panel in Korean patients with operable breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-03-10.

Germline and somatic mtDNA mutations in mouse aging

The accumulation of acquired mitochondrial genome (mtDNA) mutations with aging in somatic cells has been implicated in mitochondrial dysfunction and linked to age-onset diseases in humans. Here, we asked if somatic mtDNA mutations are also associated with aging in the mouse. MtDNA integrity in multiple organs and tissues in young and old (2-34 months) wild type (wt) mice was investigated by whole genome sequencing. Remarkably, no acquired somatic mutations were detected in tested tissues. However, we identified several non-synonymous germline mtDNA variants whose heteroplasmy levels (ratio of normal to mutant mtDNA) increased significantly with aging suggesting clonal expansion of inherited mtDNA mutations. Polg mutator mice, a model for premature aging, exhibited both germline and somatic mtDNA mutations whose numbers and heteroplasmy levels increased significantly with age implicating involvement in premature aging. Our results suggest that, in contrast to humans, acquired somatic mtDNA mutations do not accompany the aging process in wt mice.

Neutrophil-lymphocyte ratio predicts response to chemotherapy in triple-negative breast cancer

Background

The neutrophil-lymphocyte ratio (nlr) has been reported to correlate with patient outcome in several cancers, including breast cancer. We evaluated whether the nlr can be a predictive factor for pathologic complete response (pcr) after neoadjuvant chemotherapy (nac) in patients with triple-negative breast cancer (tnbc).

Methods

We analyzed the correlation between response to nac and various factors, including the nlr, in 87 patients with tnbc who underwent nac. In addition, we analyzed the association between the nlr and recurrence-free survival (rfs) in patients with tnbc.

Results

Of the 87 patients, 25 (28.7%) achieved a pcr. A high Ki-67 index and a low nlr were significantly associated with pcr. The pcr rate was higher in patients having a high Ki-67 index (≥15%) than in those having a low Ki-67 index (35.7% vs. 0%, p = 0.002) and higher in patients having a low nlr (≤1.7) than in those having a high nlr (42.1% vs. 18.4%, p = 0.018). In multiple logistic analysis, a low nlr remained the only predictive factor for pcr (odds ratio: 4.274; p = 0.008). In the survival analysis, the rfs was significantly higher in the low nlr group than in the high nlr group (5-year rfs rate: 83.7% vs. 66.9%; log-rank p = 0.016).

Conclusions

Our findings that the nlr is a predictor of pcr to nac and also a prognosticator of recurrence suggest an association between response to chemotherapy and inflammation in patients with tnbc. The pretreatment nlr can be a useful predictive and prognostic marker in patients with tnbc scheduled for nac.

Three-Dimensional Dialysate flow Analysis in a Hollow-Fiber Dialyzer by Perfusion Computed Tomography

Perfusion computed tomography (PCT) is a means to rapidly and easily evaluate cerebral perfusion in patients presenting with acute stroke symptoms, which provides insights into capillary-level hemodynamics. In this study, we used PCT to analyze the 3-dimensional dialysate flow in a low-flux hemodialyzer equipped with a standard fiber bundle. The dynamic CT studies were performed with 64-channel multi-detector row CT (MDCT) at a dialysate flow rate of 500 ml/min and a 1.0 ml/sec injection rate of contrast agent. Central volume principle was used to calculate hydrodynamic parameters by deconvolution of time-density curves (TDCs). Functional maps of dialysate flow (DF), dialysate volume (DV), and mean transit time (MTT) could quantitatively describe the dialysate flow maldistribution, variations in fiber packing, and perfusion pressure distribution in a hemodialyzer, respectively. PCT by means of analysis was able to overcome the limitations of conventional imaging techniques for analyzing dialysate flow distributions in hollow-fiber dialyzers. Not only local hydrodynamic phenomena at microscopic level but also macroscopic flow behavior of dialysate were visualized quantitatively. Therefore, we concluded that PCT is a quantitative analysis method to provide better insights into hydrodynamics of hollow-fiber dialyzers and is expected to contribute to optimization of artificial kidneys.