The role of lipids in genome integrity and pluripotency.

Pluripotent stem cells (PSCs), comprising embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), offer immense potential for regenerative medicine due to their ability to differentiate into all cell types of the adult body. A critical aspect of harnessing this potential is understanding their metabolic requirements during derivation, maintenance, and differentiation in vitro. Traditional culture methods using fetal bovine serum often lead to issues such as heterogeneous cell populations and diminished pluripotency. Although the chemically-defined 2i/LIF medium has provided solutions to some of these challenges, prolonged culturing of these cells, especially female ESCs, raises concerns related to genome integrity. This review discusses the pivotal role of lipids in genome stability and pluripotency of stem cells. Notably, the introduction of lipid-rich albumin, AlbuMAX, into the 2i/LIF culture medium offers a promising avenue for enhancing the genomic stability and pluripotency of cultured ESCs. We further explore the unique characteristics of lipid-induced pluripotent stem cells (LIP-ESCs), emphasizing their potential in regenerative medicine and pluripotency research.

Characterizing physiological high-frequency oscillations using deep learning.

Objective.Intracranially-recorded interictal high-frequency oscillations (HFOs) have been proposed as a promising spatial biomarker of the epileptogenic zone. However, HFOs can also be recorded in the healthy brain regions, which complicates the interpretation of HFOs. The present study aimed to characterize salient features of physiological HFOs using deep learning (DL).Approach.We studied children with neocortical epilepsy who underwent intracranial strip/grid evaluation. Time-series EEG data were transformed into DL training inputs. The eloquent cortex (EC) was defined by functional cortical mapping and used as a DL label. Morphological characteristics of HFOs obtained from EC (ecHFOs) were distilled and interpreted through a novel weakly supervised DL model.Main results.A total of 63 379 interictal intracranially-recorded HFOs from 18 children were analyzed. The ecHFOs had lower amplitude throughout the 80-500 Hz frequency band around the HFO onset and also had a lower signal amplitude in the low frequency band throughout a one-second time window than non-ecHFOs, resembling a bell-shaped template in the time-frequency map. A minority of ecHFOs were HFOs with spikes (22.9%). Such morphological characteristics were confirmed to influence DL model prediction via perturbation analyses. Using the resection ratio (removed HFOs/detected HFOs) of non-ecHFOs, the prediction of postoperative seizure outcomes improved compared to using uncorrected HFOs (area under the ROC curve of 0.82, increased from 0.76).Significance.We characterized salient features of physiological HFOs using a DL algorithm. Our results suggested that this DL-based HFO classification, once trained, might help separate physiological from pathological HFOs, and efficiently guide surgical resection using HFOs.

Use of video-based telehealth services using a mobile app for workers in underserved areas during the COVID-19 pandemic: A prospective observational study.

BACKGROUND: The COVID-19 pandemic has limited face-to-face treatment, triggering a change in the structure of existing healthcare services. Unlike other groups, workers in underserved areas have relatively poor access to healthcare. OBJECTIVE: This study aimed to investigate the effects of video-based telehealth services using a mobile personal health record (PHR) app for vulnerable workers with metabolic risk factors. METHODS: A prospective observational study was conducted with 117 participants and 27 healthcare professionals for 16 weeks. Participants visited the research institution three times (at weeks 1, 8, and 16) and underwent health check-ups and used various features of the mobile PHR app. Healthcare professionals observed the participants's data using the monitoring system and performed appropriate interventions. The primary outcome measures were to evaluate the effects of services on changes in the participants' metabolic risk factors, and secondary outcome measures were to analyze changes in the participants' lifestyle and service satisfaction, and to observe service use through usage logs. One-way repeated measures ANOVA and Scheffé's test were performed to observe changes in participants' health status and lifestyle, and a paired t-test was performed to analyze changes in service satisfaction. Finally, in-depth interviews with healthcare professionals were performed using semi-structured questionnaires to understand service providers' perspectives after the end of the study. RESULTS: Systolic blood pressure (F = 7.32, P <.001), diastolic blood pressure (F = 11.30, P <.001), body weight (F = 29.53, P <.001), BMI (F = 17.31, P <.001), waist circumference (F = 17.33, P <.001), fasting blood glucose (F = 5.11, P =.007), and triglycerides (F = 4.66, P =.01) showed significant improvements with time points, whereas high-density lipoprotein cholesterol (F = 3.35, P =.067) did not. The dietary score (F = 3.26, P =.04) showed a significant improvement with time points, whereas physical activity (F = 1.06, P =.34) did not. In terms of service satisfaction, only lifestyle improvement (P <.001) showed a significant difference. COVID-19 has affected the performance of healthcare professionals, thereby changing the perspectives toward healthcare technology services. CONCLUSIONS: We evaluated the effectiveness of video-based telehealth services supporting workers' health status and lifestyle interventions using healthcare technologies such as the mobile PHR app, tele-monitoring, and video teleconsultation. Our results indicate that as a complementary means, its utility can be expanded in the field of occupational safety and health to overcome the limitations of face-to-face treatment due to COVID-19 in the future.

A Worker-Centered Personal Health Record App for Workplace Health Promotion Using National Health Care Data Sets: Design and Development Study.

BACKGROUND: Personal health record (PHR) technology can be used to support workplace health promotion, and prevent social and economic losses related to workers' health management. PHR services can not only ensure interoperability, security, privacy, and data quality, but also consider the user's perspective in their design. OBJECTIVE: Using Fast Healthcare Interoperability Resources (FHIR) and national health care data sets, this study aimed to design and develop an app for providing worker-centered, interconnected PHR services. METHODS: This study considered the user's perspective, using the human-centered design (HCD) methodology, to develop a PHR app suitable for occupational health. We developed a prototype after analyzing quantitative and qualitative data collected from workers and a health care professional group, after which we performed a usability evaluation. We structured workers' PHR items based on the analyzed data, and ensured structural and semantic interoperability using FHIR, Systematized Nomenclature of Medicine-Clinical Terms (SNOMED-CT), and Logical Observation Identifiers Names and Codes (LOINC). This study integrated workers' health information scattered across different Korean institutions through an interface method, and workers' PHRs were managed through a cloud server, using Azure API for FHIR. RESULTS: In total, 562 workers from industrial parks participated in the quantitative study. The preferred data items for PHR were medication, number of steps walked, diet, blood pressure, weight, and blood glucose. The preferred features were ability to access medical checkup results, health information content provision, consultation record inquiry, and teleconsultation. The worker-centered PHR app collected data on, among others, life logs, vital signs, and medical checkup results; offered health care services such as reservation and teleconsultation; and provided occupational safety and health information through material safety data sheet search and health questionnaires. The app reflected improvements in user convenience and app usability proposed by 19 participants (7 health care professionals and 12 end users) in the usability evaluation. The After-Scenario Questionnaire (ASQ) was evaluated with a mean score of 5.90 (SD 0.34) out of 7, and the System Usability Scale (SUS) was evaluated a mean score of 88.7 (SD 4.83) out of 100. CONCLUSIONS: The worker-centered PHR app integrates workers' health information from different institutions and provides a variety of health care services from linked institutions through workers' shared PHR. This app is expected to increase workers' autonomy over their health information and support medical personnel's decision making regarding workers' health in the workplace. Particularly, the app will provide solutions for current major PHR challenges, and its design, which considers the user's perspective, satisfies the prerequisites for its utilization in occupational health.

Using an Audience Response System Smartphone App to Improve Resident Education in the Pediatric Intensive Care Unit.

In the Pediatric Intensive Care Unit (PICU), most teaching occurs during bedside rounds, but technology now provides new opportunities to enhance education. Specifically, smartphone apps allow rapid communication between instructor and student. We hypothesized that using an audience response system (ARS) app can identify resident knowledge gaps, guide teaching, and enhance education in the PICU. Third-year pediatric residents rotating through the PICU participated in ARS-based education or received traditional teaching. Before rounds, experimental subjects completed an ARS quiz using the Socrative app. Concomitantly, the fellow leading rounds predicted quiz performance. Then, discussion points based on the incorrect answers were used to guide instruction. Scores on the pre-rotation test were similar between groups. On the post-rotation examination, ARS participants did not increase their scores more than controls. The fellow's prediction of performance was poor. Residents felt that the method enhanced their education whereas fellows reported that it improved their teaching efficiency. Although there was no measurable increase in knowledge using the ARS app, it may still be a useful tool to rapidly assess learners and help instructors provide learner-centered education.

Transcriptome analysis and identification of significantly differentially expressed genes in Holstein calves subjected to severe thermal stress.

RNA-Seq analysis was used to characterize transcriptome response of Holstein calves to thermal stress. A total of eight animals aged between 2 and 3 months were randomly selected and subjected to thermal stress corresponding to a temperature humidity index of 95 in an environmentally controlled house for 12 h consecutively for 3 days. A set of 15,787 unigenes were found to be expressed and after a threshold of threefold change, and a Q value <0.05; 502, 394, and 376 genes were found to be differentially expressed on days 1, 2, and 3 out of which 343, 261 and 256 genes were upregulated and 159, 133, and 120 genes were downregulated. Only 356 genes out of these were expressed on all 3 days, and only they were considered as significantly differentially expressed. KEGG pathway analysis revealed that ten pathways were significantly enriched; the top two among them were protein processing in endoplasmic reticulum and MAPK signaling pathways. These results suggest that thermal stress triggered a complex response in Holstein calves and the animals adjusted their physiological and metabolic processes to survive. Many of the genes identified in this study have not been previously reported to be involved in thermal stress response. The results of this study extend our understanding of the animal's response to thermal stress and some of the identified genes may prove useful in the efforts to breed Holstein cattle with superior thermotolerance, which might help in minimizing production loss due to thermal stress.

Characterization of genes and pathways that respond to heat stress in Holstein calves through transcriptome analysis.

This study aimed to investigate the genes and pathways that respond to heat stress in Holstein bull calves exposed to severe ranges of temperature and humidity. A total of ten animals from 4 to 6 months of age were subjected to heat stress at 37 °C and 90 % humidity for 12 h. Skin and rectal temperatures were measured before and after heat stress; while no correlation was found between them before heat stress, a moderate correlation was detected after heat stress, confirming rectal temperature to be a better barometer for monitoring heat stress. RNAseq analysis identified 8567 genes to be differentially regulated, out of which 465 genes were significantly upregulated (≥2-fold, P < 0.05) and 49 genes were significantly downregulated (≤2-fold, P < 0.05) in response to heat stress. Significant terms and pathways enriched in response to heat stress included chaperones, cochaperones, cellular response to heat stress, phosphorylation, kinase activation, immune response, apoptosis, Toll-like receptor signaling pathway, Pi3K/AKT activation, protein processing in endoplasmic reticulum, interferon signaling, pathways in cancer, estrogen signaling pathway, and MAPK signaling pathway. The differentially expressed genes were validated by quantitative real-time PCR analysis, which confirmed the tendency of the expression. The genes and pathways identified in this analysis extend our understanding of transcriptional response to heat stress and their likely functioning in adapting the animal to hyperthermic stress. The identified genes could be used as candidate genes for association studies to select and breed animals with improved heat tolerance.

Confirmation of genotypic effects for the bovine APM1 gene on marbling in Hanwoo cattle.

BACKGROUND: Our previous study had identified the SNP (g.81966377T > C) and indel (g.81966364D > I) located in the promoter of APM1 to have a significant effect on marbling in Hanwoo. APM1 encodes an adipocytokine called adiponectin, which plays a significant role in lipogenesis. The aim of this study was to verify and validate the effect of the SNP and indel on marbling and other carcass traits in a large, representative, countrywide population of Hanwoo cattle. The carcass traits measured were marbling (MAR), backfat thickness (BFT), loin eye area (LEA), and carcass weight (CAW). RESULTS: Primers were designed to amplify 346 bp of the genomic segment that contained the targeted SNP (g.81966377) and the indel (g.81966364). After data curation, the genotypes of 8,378 individuals identified using direct sequencing analysis estimated frequencies for C (0.686) and T (0.314) respectively showing genotype frequencies for CC (0.470), CT (0.430) and TT (0.098). The genotypes were significantly associated with MAR, BFT and LEA. The indel had significant effect on marbling (P < .0001) with strong additive genetic effects. The allele frequencies was estimated at (DEL, 0.864) and insertion (INS, 0.136) presenting genotypes of D/D (75.63 %), D/I (21.44 %), and I/I (2.92 %). Significant departure from Hardy-Weinberg equilibrium was not detected for both the SNP and the indel. CONCLUSION: The SNP genotypes showed significant association with MAR, BFT and LEA with strong additive genetic effects, while the indel was significantly associated with MAR. The results confirmed that the variants can be used as a genetic marker for improving marbling in Hanwoo.

Effects of genetic variants for the swine FABP3, HMGA1, MC4R, IGF2, and FABP4 genes on fatty acid composition.

This study aimed to verify genetic relationships between fatty acid composition (FAC) and genotypes of several genes (FABP3, HMGA1, MC4R, IGF2, and FABP4) using pig breeds. The effects of genetic variations on FAC of the longissimus muscle were statistically significant with additive and dominance effects. The polymorphisms of FABP3 and IGF2 had the largest effects on stearic (C18:0, P=0.009) and γ-linoleic (C18:3n6, P=0.039) acids, respectively, whereas HMGA1 and FABP4 did not show significances. The analysis revealed that MC4R was significantly associated with palmitoleic acid (C16:ln7) and MUFA. Allele frequencies of the genes examined in this analysis were significantly skewed or fixed in the Korean native pig (KNP), whereas the allele frequencies of the crossbreds tended to fall between those of the purebreds except that HMGA1 and FABP4 had approximately the same allele frequencies with Duroc and KNP, respectively. The polymorphisms found in this study could be used as genetic markers in breeding programs to simultaneously change proportions of fatty acids in muscle tissues.

Effects of genetic variants in the promoter region of the bovine adiponectin (ADIPOQ) gene on marbling of Hanwoo beef cattle.

This study aimed to verify genetic effects of the bovine adiponectin (ADIPOQ) gene on carcass traits of Hanwoo cattle. The measured carcass traits were marbling score (MAR), backfat thickness (BFT), loineye area (LEA), and carcass weight (CAW). Selection of primers was based on the bovine ADIPOQ sequence, and the analysis amplified approximately 267 and 333 bp genomic segments, including 67 bp of insertions in the promoter region. Sequencing analysis confirmed genetic variants (g.81966235C>T, g.81966377T>C, and g.81966364D>I) that showed significant effects on MAR. The present results suggest that the identified SNPs are useful genetic markers for the improvement of carcass traits in Hanwoo cattle.

Effects of genetic variants for the bovine calpain gene on meat tenderness.

The objective of this study was to determine whether the genetic variants of CAPN1 developed in several cattle populations can be applied for Hanwoo, regarding genetic effects on meat traits. The traits were examined for 286 purebred Hanwoo steers with genotypes classified by restriction fragment length polymorphism (RFLP) and single strand conformation polymorphism (SSCP) analysis. The nucleotide positions of primers and previously identified genetic variants were based on sequences of the calpain 1 (CAPN1) gene with GenBank accession numbers (AF252504, AF248054, and AY639597). The analysis of genetic distribution estimated levels of minor allele frequencies ranged from 0.165 to 0.392, showing no significant departures from Hardy-Weinberg Equilibrium for all markers. Overall averages of heterozygosites (He) and polymorphic information contents (PICs) for all markers were calculated to 0.503 and 0.429, respectively, and the g.4558G>A marker showed the lowest He (0.425) and PIC (0.367). Animals from 29 months of age were slaughtered to measure Warner-Bratzler shear force (WBSF), cooking loss, water-holding capacity, pH, fat, and moisture. All the CAPN1 markers explained variations of WBSF, showing significant additive effects except g.5709G>A. A significant marginal mean difference in genotypes of g.6545C>T (P=0.046) was found in moisture with additive effects. From the result it may be possible to use three calpain markers (g.4558G>A, g.4685C>T, and g.6545C>T) classified by RFLP and SSCP analysis in marker assisted selection programs to improve WBSF as meat tenderness in Hanwoo.

Gene expression in bovine rumen epithelium during weaning identifies molecular regulators of rumen development and growth.

During weaning, epithelial cell function in the rumen transitions in response to conversion from a pre-ruminant to a true ruminant environment to ensure efficient nutrient absorption and metabolism. To identify gene networks affected by weaning in bovine rumen, Holstein bull calves were fed commercial milk replacer only (MRO) until 42 days of age, then were provided diets of either milk + orchardgrass hay (MH) or milk + grain-based calf starter (MG). Rumen epithelial RNA was extracted from calves sacrificed at four time points: day 14 (n = 3) and day 42 (n = 3) of age while fed the MRO diet and day 56 (n = 3/diet) and day 70 (n = 3/diet) while fed the MH and MG diets for transcript profiling by microarray hybridization. Five two-group comparisons were made using Permutation Analysis of Differential Expression® to identify differentially expressed genes over time and developmental stage between days 14 and 42 within the MRO diet, between day 42 on the MRO diet and day 56 on the MG or MH diets, and between the MG and MH diets at days 56 and 70. Ingenuity Pathway Analysis (IPA) of differentially expressed genes during weaning indicated the top 5 gene networks involving molecules participating in lipid metabolism, cell morphology and death, cellular growth and proliferation, molecular transport, and the cell cycle. Putative genes functioning in the establishment of the rumen microbial population and associated rumen epithelial inflammation during weaning were identified. Activation of transcription factor PPAR-α was identified by IPA software as an important regulator of molecular changes in rumen epithelium that function in papillary development and fatty acid oxidation during the transition from pre-rumination to rumination. Thus, molecular markers of rumen development and gene networks regulating differentiation and growth of rumen epithelium were identified for selecting targets and methods for improving and assessing rumen development and function, particularly in the growing calf.

Prognostic value of postoperative CA19-9 normalization in patients with advanced gastric cancer.

BACKGROUND/AIMS: CA19-9 is known to have positive correlation with depth of invasion, nodal involvement, and peritoneal metastasis in gastric adenocarcinoma. In patients with high preoperative CA19-9 serum levels who underwent curative gastrectomy, we evaluated the prognostic impact of postoperative normalization of CA 19-9. METHODOLOGY: Among 1,439 patients who underwent curative gastrectomy for advanced gastric adenocarcinoma, data of 102 patients with advanced gastric adenocarcinoma whose preoperative serum CA19-9 level was higher than cutoff value (37 U/mL) were reviewed. If serum CA19-9 level had fallen below 37 U/mL at 6 months after surgery, the CA19-9 level was considered normalized. RESULTS: CA19-9 levels were normalized in 79 patients but not in 23 patients. There were statistically significant differences in prognosis according to depth of invasion, presence of lymph node metastasis, extent of gastric resection, and postoperative CA19-9 normalization on univariate analyses. Multivariate analysis revealed that pathological lymph node metastasis (p<0.001) and postoperative CA19-9 normalization were independent prognostic factors (p=0.001). CONCLUSIONS: In patients with advanced gastric adenocarcinoma who underwent curative gastric resection, postoperative normalization of CA19-9 can be a surrogate for potentially curative surgical treatment and can be used as a good prognostic factor.

Aquaporin 3 expression is up-regulated by TGF-ß1 in rat peritoneal mesothelial cells and plays a role in wound healing.

Aquaporin 3 (AQP3) is expressed in many tissues including the peritoneum and kidney. In cultured mesothelial cells, glucose up-regulates AQP3, which may be important for water transport through the peritoneal membrane. However, there has been no research into the role of AQP3 in human peritoneal mesothelial cell (HPMC) migration or peritoneal fibrosis. We investigated the effects of transforming growth factor-ß1 (TGF-ß1) on AQP3 expression in HPMCs. We also investigated the role of AQP3 in the peritoneal wound healing process in rats. Chronic exposure to glucose-containing solution increased peritoneal myofibroblasts, with TGF-ß1 and AQP3 expression in a model of long-term peritoneal dialysis. In vitro, TGF-ß1 induced AQP3 expression in HPMCs. AQP3 knockdown by small-interfering RNA inhibited TGF-ß1-induced AQP3 and α-smooth muscle actin expression and also slowed HPMC migration. AQP3 overexpression induced faster migration of HPMCs. Treatment with an extracellular signal-regulated kinase inhibitor and p38 kinase inhibitor attenuated TGF-ß1-induced AQP3 expression in HPMCs. These data suggest that TGF-ß1 induces AQP3 and that AQP3 has a critical role in TGF-ß-induced HPMC migration. These findings provide evidence of a novel role for AQP3 in peritoneal fibrosis and wound healing. The effect of TGF-ß1 on AQP3 expression in HPMCs is mediated, at least in part, by ERK and p38 signaling.

Analysis of copy number variations in Holstein cows identify potential mechanisms contributing to differences in residual feed intake.

Genomic structural variation is an important and abundant source of genetic and phenotypic variation. In this study, we performed an initial analysis of copy number variations (CNVs) using BovineHD SNP genotyping data from 147 Holstein cows identified as having high or low feed efficiency as estimated by residual feed intake (RFI). We detected 443 candidate CNV regions (CNVRs) that represent 18.4 Mb (0.6 %) of the genome. To investigate the functional impacts of CNVs, we created two groups of 30 individual animals with extremely low or high estimated breeding values (EBVs) for RFI, and referred to these groups as low intake (LI; more efficient) or high intake (HI; less efficient), respectively. We identified 240 (~9.0 Mb) and 274 (~10.2 Mb) CNVRs from LI and HI groups, respectively. Approximately 30-40 % of the CNVRs were specific to the LI group or HI group of animals. The 240 LI CNVRs overlapped with 137 Ensembl genes. Network analyses indicated that the LI-specific genes were predominantly enriched for those functioning in the inflammatory response and immunity. By contrast, the 274 HI CNVRs contained 177 Ensembl genes. Network analyses indicated that the HI-specific genes were particularly involved in the cell cycle, and organ and bone development. These results relate CNVs to two key variables, namely immune response and organ and bone development. The data indicate that greater feed efficiency relates more closely to immune response, whereas cattle with reduced feed efficiency may have a greater capacity for organ and bone development.

Design of a bovine low-density SNP array optimized for imputation.

The Illumina BovineLD BeadChip was designed to support imputation to higher density genotypes in dairy and beef breeds by including single-nucleotide polymorphisms (SNPs) that had a high minor allele frequency as well as uniform spacing across the genome except at the ends of the chromosome where densities were increased. The chip also includes SNPs on the Y chromosome and mitochondrial DNA loci that are useful for determining subspecies classification and certain paternal and maternal breed lineages. The total number of SNPs was 6,909. Accuracy of imputation to Illumina BovineSNP50 genotypes using the BovineLD chip was over 97% for most dairy and beef populations. The BovineLD imputations were about 3 percentage points more accurate than those from the Illumina GoldenGate Bovine3K BeadChip across multiple populations. The improvement was greatest when neither parent was genotyped. The minor allele frequencies were similar across taurine beef and dairy breeds as was the proportion of SNPs that were polymorphic. The new BovineLD chip should facilitate low-cost genomic selection in taurine beef and dairy cattle.

Portal venous gas: a clinical finding in obstructed infracardiac total anomalous pulmonary venous connection.

Total anomalous pulmonary venous connection is a cyanotic congenital heart defect that presents with a multitude of clinical presentations. We report a case of obstructive total anomalous pulmonary venous connection (TAPVC) which presented in a way that has not previously been described. An infant with mixed type obstructive TAPVC was found to have pulmonary interstitial emphysema and portal venous gas on a scout radiograph obtained prior to computed tomography scan. The presence of portal venous gas indicated a connection between the pulmonary venous system and the portal venous system infradiaphragmatically.

Effects of genetic variants for the calpastatin gene on calpastatin activity and meat tenderness in Hanwoo (Korean cattle).

This study was designed to investigate the effects of calpastatin genotypes determined by PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism) on calpastatin activity (CAC) and Warner-Bratzler Shear Force (WBS). Longissimus muscles were prepared from 379 Hanwoo bulls aged approximately 20months. The selection of PCR primers was based on exons (27 and 28) of the bovine calpastatin cDNA sequences, and genetic variants were detected by SSCP analysis using Taq I restriction enzymes. Sequencing analysis confirmed 4 restriction sites (nucleotide positions 52, 67, 796, and 1369), and a genetic variant was verified at a nucleotide position 641 (C/T substitutions) based on sequences (AF281256). The CAST28 genotypes showing allele frequencies of C (0.429) and T (0.571) were significantly associated with CAC and WBS. A significant positive residual correlation (r=0.121, P=0.02) between CAC and WBS was obtained.

Phosphate-induced apoptosis in human peritoneal mesothelial cells in vitro.

BACKGROUND: It has been demonstrated that phosphate uptake through the type III sodium-dependent phosphate co-transporter, Pit-1, induced apoptosis of aortic vascular smooth muscle cells and endothelial cells in vitro. However, the apoptotic effects of high phosphate (HP) level in human peritoneal mesothelial cells (HPMCs) are not known. METHODS: To examine whether Pit-1 is expressed in HPMCs, we checked the Western blot assay of immunoreactive Pit-1 and the transcription of Pit-1 by reverse transcriptase PCR. We treated several different phosphate concentrations (1-4 mM) and calcium concentrations (1.8 and 2.8 mM) on HPMCs to assess the effects of concentration. MTT, TUNEL assays, and flow cytometry analysis using Annexin V and propidium iodide were performed to identify cell death and apoptosis. Bax and Bcl-2 by Western blot and caspase-3 activity were evaluated by colorimetric assay. In addition, phosphonoformic acid (PFA) and pan-caspase inhibitor, Z-VAD-FMK, were given to prevent phosphate-induced apoptosis. RESULTS: Pit-1 expression on HPMCs was demonstrated. Apoptosis in HPMCs significantly increased with a high concentration of phosphate in a dose- and time-dependent manner, and was enhanced in the presence of 2.8 mM calcium. HP concentrations significantly decreased the anti-apoptotic Bcl-2/Bax ratio and increased caspase-3 activity. The treatment with PFA and Z-VAD-FMK prevented cell death by HP. CONCLUSION: Phosphate uptake through Pit-1 induces apoptosis in HPMCs by a caspase-related mechanism.