Detection of joining points for genomic DNA circularization in cell culture.

We previously reported on extrachromosomal circular DNA extracted from mouse brain. We attempted to reconfirm the formation of circular DNA from this region in a culture system. From a circular DNA-enriched fraction of a mouse embryonic tumor-derived cell line capable of inducing neuronal differentiation, circular DNA in the same region was isolated by nested inverse polymerase chain reaction as performed previously. We attempted to amplify and identify some junctions that were evidence of circularization. In this analysis, we captured several junctions that indicated circularization in cultured cells induced to differentiate into neurons. We observed that some of the sequences shared the same point of attachment, indicating that there exist genomic sequences that are amenable to binding toward circularization. Cells were X-ray-irradiated to determine whether any transformation occurred in DNA circularization. Consequently, circularization junctions occurred after differentiation-induced stimulation and before and after X-ray irradiation. This finding indicated that circularization junctions can be formed from this region without being inhibited by X-ray irradiation and irrespective of cell differentiation stage. Furthermore, the presence of circular DNA was confirmed in which genomic fragments from different chromosomes were replaced. These findings suggest that extrachromosomal circular DNA contributes to the interchromosomal translocation of genomic fragments.

Calorie restriction delays cardiac senescence and improves cardiac function in obese diabetic rats.

The aims of this study were to investigate the impact of caloric restriction (CR) on cardiac senescence in an animal model of diabetes and examine the signal transduction mechanisms for changes in cell survival as well as cardiac function. Male 8-week-old Otsuka Long-Evans Tokushima fatty (OLETF) diabetic rats were divided into 2 groups: a group fed ad libitum (AL), and a group fed with CR (30% energy reduction). Long-Evans Tokushima Otsuka (LETO) non-diabetic rats were used as controls. LETO rats were divided into 3 groups: a high fat diet (HFD) group with a 22% increase in caloric intake, a CR group, and a group fed AL. At 40 weeks of age, the telomere length was significantly shorter in the heart tissue of HFD rats but was not altered by CR in experimental rats with or without CR, however, telomerase activity in both strains of CR rats was significantly elevated. Protein expression of IGF-1, Sirt 1 and phospho-FoxO1 was increased in both CR groups. Echocardiography showed that CR preserved LV diastolic function with a significantly shorter E-wave deceleration time and a greater E/A ratio compared with the AL groups. These findings suggest that CR protocol increased telomerase activity without changing of telomere length, enhanced autophagy and improved LV diastolic function in animal model of diabetes rats. It is finally suggested that those impacts may be important for the maintenance of normal cardiac function and for delayed cardiac aging.

Chromosomal terminal methylation status is associated with gut microbiotic alterations.

We explored the association of fecal bacterial species and somatic telomere changes in patients with chronic disease. The results showed that the length of the combined range of telomere and the methylated subtelomere was correlated with the increase of bacteria species and the numerical superiority of certain strains in feces, the increase of streptococci in men and women, and the increase of E. coli specifically in women. These results suggest that the aging status reflected by telomere length and/or demethylation of neighboring regions correlate with intestinal conditions which influences the proportion of the intestinal microbial population. Shortened telomere length and subtelomeric demethylation status are thought to represent the degree of aging and the accelerating stage of aging velocity, respectively. Hence, the observed biased microbial status is considered to be associated with advanced stage or acceleration phase of biological aging.

Telomere shortening velocity of patients administered with hypnotics is accelerated in a gender-differential manner.

The telomere length and its distribution were compared between patients administered with and without hypnotics to see if regular administration of hypnotics is associated with their aging-related somatic telomere shortening. Male patients presented significant shortening of telomere length of circulating leukocytes in association with age (-41.9 bp/year, p = 0.045) in contrast with controls (-18.3 kb/year, p = 0.155). On the other hand, female patients presented no significant shortening of telomere length with aging (-16.4 bp/year, p = 0.372) in contrast with controls (-55.9 bp/year, p = 0.00005). These results suggested that regular administration of hypnotics is associated with aging progression in a gender-related manner. The administration of hypnotics could be an indicator as the somatic aging status and for the screening of background lifestyle-associated diseases promoting biological aging.

Shorter somatic telomere can be an increased risk for hospitalization.

Somatic telomere DNA length is known to shorten with certain disease states and senescence. Furthermore, we have reported that the telomere length of a sub-healthy population also correlates with the blood data of laboratory tests. These facts suggest that patients with shorter telomere length tend to be hospitalized more easily than patients with longer telomere length. And such hospitalization tendencies can also be reflected in differences in clinical laboratory data. To address this issue, we evaluated and compared the telomere length and clinical laboratory data of outpatients and inpatients. In this study, 35 inpatients with chronic illness and 38 outpatients with one or more weeks without hospitalization experience were enrolled. Telomere length was shorter in hospitalized patients than outpatients. Inpatients and outpatients showed significant differences in some laboratory test results. Male outpatients showed higher values of fast blood sugar, HbA1c, blood urea nitrogen, creatinine, C-reactive protein, red blood cell count, and hemoglobin. Among female outpatients, the values of aspartate aminotransferase, alanine aminotransferase, albumin, creatine kinase, red blood cell count and hemoglobin were high. Of these, only albumin levels showed a positive correlation with telomere length in both sexes. Unexpectedly, all the other clinical data distinguishing outpatients and inpatients showed no significant association with telomere length. These items appeared to be related to hospital risk independently of TL. Having a shorter somatic telomere length appeared to be at a higher risk of hospitalization. This risk can be augmented by further complications such as deterioration of nutritional status and anemia. Maintaining sufficiently high nutritional status and erythropoietic potential may lead to avoidance of clinical events that require hospitalization.

The approximate formulas predicting personal somatic telomere length using patient blood test data.

Biological aging underlies lifestyle-related diseases. It can be assessed by measuring personal somatic cell telomere length. However, measuring the telomere length is laborious, and its clinical surrogate parameters have not been developed. This study analyzed the correlation between telomere length in peripheral leukocytes and laboratory data to select test items relating closely to biological aging. We established formulas from these clinical data to predict the personal telomere length. The subjects were patients having visited Kyushu University Beppu Hospital from 2012 to 2015. Two hundred and thirty-two patients were enrolled. The blood data were collected and telomere lengths were measured by Southern blotting method. The patients showed significant correlations between the telomere length and several blood test data with a sex-related difference. Candidate formulas are as follows: Predicted telomere length (kb) in men = 8.59 - 0.037 × Age (years) + 0.024 × Hemoglobin (g/dL); Predicted telomere length (kb) in women = 4.83 - 0.019 × Age (years) + 0.23 × Albumin (g/dL) + 0.0001 × White blood cells (/mm3) + 0.0020 × Red blood cells (× 104/mm3) + 0.0032 × Total cholesterol (mg/dL). Thus, the derived formulas allow for the accurate differential prediction of telomeric length in male and female patients.

Short telomere subtelomeric hypomethylation is associated with telomere attrition in elderly diabetic patients 1.

Telomere shortening is well known to be associated with the aging process and aging-associated diseases, including diabetes. The telomere length and subtelomeric methylation status in peripheral leucocytes (LTL) were compared in elderly type 2 diabetes (T2D) patients and diabetes-free controls (C). The methylation status was analyzed between MspI-TRF lengths and HpaII-TRF lengths by using methylation-sensitive and -insensitive restriction enzyme isoschizomers, MspI and HpaII, respectively. The mean telomere lengths, MspI-TRF or HpaII-TRF, were not significantly different between C and T2D patients. The percentage of fractionated densitometry showed that long and middle telomeres (>9.4 kb, 4.4-9.4 kb) were unaltered but short telomeres (<4.4 kb) in T2D patients were increased compared with C group. The methylation status revealed subtelomeric hypomethylation in short telomeres of T2D patients. When some patients with T2D were treated with 3-hydroxy-3-methylglutaril coenzyme A (HMG-CoA) reductase inhibitors (statin), results seen in short telomere of T2D patients were not observed and were not different from C. This suggested that this altered subtelomeric hypomethylation may be associated with the accelerated telomere shortening in elderly diabetic patients. These results also mean that the subtelomeric hypomethylation can also be influenced by statin treatment in T2D.

Clinical and anti-aging effect of mud-bathing therapy for patients with fibromyalgia.

Spa bathing is known as a medical treatment for certain diseases causing chronic pains. Spa water contains mineral components which lower the specific heat of the water, resulting in a higher efficiency to warm body-core temperature. This phenomenon yields pain-relieving effect for rheumatoid arthritis, low back pain, sciatic neuralgia, fibromyalgia, etc. Here we introduce medical and biological effects of mud-spa-bathing therapy for fibromyalgia other than pain relief, the changes of blood examination data, and the telomere length of circulating leukocytes. The enrolled 7 patients with fibromyalgia syndrome were hospitalized and were subject to daily mud bathing at 40 °C for 10 min for about a month. Then, their subjective pain was reduced to about a quarter in average. They also showed lowered serum triglyceride and C-reactive protein level, maintaining the levels of aspartate transaminase and creatine phosphokinase, and increases of the red blood cell count, the serum albumin level, and the serum LDL-cholesterol level in comparison with cases without mud-bathing therapy, suggesting that mud bathing prevents inflammation and muscle atrophy and improves nutritional condition in fibromyalgia. In addition, the analysis of telomere length of peripheral leukocytes revealed a trend of negative correlation between telomere shortening and laboratory data change of hemoglobin and serum albumin. These telomeric changes can be explained hypothetically by an effect of mud bathing extending life-span of circulating leukocytes.

Vitamin E administration erases an enhanced oxidation in multiple sclerosis.

Systemic peroxidation status has been reported as a pathogenic factor for multiple sclerosis (MS). Systemically elevated oxidation levels are associated with serum lipid peroxidation and somatic telomere length (TL) shortening. We investigated whether vitamin E (VE) administration suppresses peroxidation and improves clinical symptoms in 34 MS patients. We analyzed serum lipid peroxidation and degree of TL in circulating leukocytes of MS patients before and after VE treatment. The oxidation level was enhanced and TL was shortened in MS. The MS population treated with VE 400 mg/day for 3 months showed significantly reduced serum lipid oxidation level with maintenance of TL. These findings showed that systemic peroxidation is associated with the development of MS. Antioxidants such as vitamin E can be candidates for supplementary therapeutic agents for MS.

Calorie restriction increases telomerase activity, enhances autophagy, and improves diastolic dysfunction in diabetic rat hearts.

The aims of this study were to investigate the impact of caloric restriction (CR) on cardiac telomere biology in an animal model of diabetes and to examine the signal transduction involved in cell senescence as well as cardiac function. Male 8-week-old Otsuka Long-Evans Tokushima fatty (OLETF) diabetic rats were divided into two groups: a group fed ad libitum (OLETF-AL) and a group fed with CR (OLETF-CR: 30% energy reduction). Long-Evans Tokushima Otsuka (LETO) non-diabetic rats were used as controls. LETO rats were also divided into two groups: a CR (LETO-CR) group and a group fed AL (LETO-AL). At 40 weeks of age, the body weight was decreased by 9.7% and the insulin resistance was less in OLETF-CR rats. Telomerase activity in OLETF-CR rats was significantly increased, and telomerase reverse transcriptase was more highly expressed in those rats. However, the telomere length (TL) was not different between AL- and CR-treated rats of each strain. The protein expressions for FoxO1 and FoxO3 were increased in OLETF-AL rats, but the levels of phosphorylated (p)-Akt were decreased compared to those in OLETF-CR rats. Autophagic LC3II signals revealed significant increases in OLETF-CR rats. Echocardiography showed that OLETF-CR improved the left ventricular diastolic dysfunction without changes in the left ventricular dimension. This study revealed that CR increases cardiac telomerase activity without TL attrition, and significantly ameliorates diastolic dysfunction. These findings suggest that cardiac telomerase activity may play an important role in the maintenance of normal cardiac function.

Patients with multiple sclerosis show increased oxidative stress markers and somatic telomere length shortening.

Lipid peroxidation due to oxidative stress (OS) may play an important role in the pathogenesis of chronic systemic inflammatory diseases such as multiple sclerosis (MS). Telomeres, repeated sequences that cap chromosome ends, undergo shortening with each cycle of cell division, resulting in cellular senescence. Research regarding telomere shortening has provided novel insight into the pathogenesis of various diseases. We hypothesized that OS damage leads to inflammatory reactions, which subsequently shortens the telomere length in MS. We enrolled 59 patients with MS, and age- and gender-matched 60 healthy controls. We divided MS subjects into three groups matched for age and gender according to the severity of disability: relatively benign course (BMS), secondary progressive MS, and primary progressive MS (PPMS). We analyzed the telomere length in peripheral blood mononuclear cells and the 8-iso-PGF2α concentration in urine, a reliable and stable marker of lipid peroxidation in vivo. The data showed significant higher levels of urinary 8-iso-PGF2α in MS subjects than in the controls. The lag-time, which represents the direct measurement of the resistance of low-density lipoprotein to oxidation, was shorter in the PPMS subjects than in the groups. Compared to that observed in the controls, the mean telomere length was significantly shorter in the PPMS group, whereas no significant telomere shortening was found between the controls and other subjects. Our data suggest that a decreased telomere length and enhanced lipid peroxidation reflects the severest stage of MS.

Altered expression of genes associated with telomere maintenance and cell function of human vascular endothelial cell at elevated temperature.

The pathophysiological alterations of vascular endothelial cells induced by heat were studied. Human umbilical venous endothelial cells were cultured for 1 day at three different temperatures (37, 39, and 42 °C). The telomere lengths, the expressions of proteins associated with telomere length maintenance, apoptosis, heat shock, and vascular function were analyzed. The cell growth was not suppressed at 39 °C but suppressed at 42 °C. The mean telomere length did not change, whereas the telomere length distribution altered at 42 °C. Long telomere decreased and middle-sized telomere increased in the telomere length distribution at 42 °C. The telomerase activity did not show any heat-associated alterations. However, of the components of telomerase, telomerase reverse transcriptase was up-regulated along temperature elevation. In contrast, the expression level of RNA component TERC did not altered. Among the analyzed apoptosis-associated proteins, p21 was down-regulated and phosphorylated p53 was up-regulated. Heat shock proteins and NO synthase were up-regulated at 42 °C. These results suggested that induced growth suppression or cell senescence was induced by strong heat stress rather than mild one predominantly in cells bearing long telomeres with p53 activation, and simultaneously activated some telomere-associated factors, heat shock proteins, and NO synthesis probably for heat-resistant cell survival.

Changes in telomere length distribution in low-dose X-ray-irradiated human umbilical vein endothelial cells.

Ionizing radiation (IR) is known to be a cause of telomere dysfunction in tumor cells; however, very few studies have investigated X-ray-related changes in telomere length and the telomerase activity in normal human cells, such as umbilical vein endothelial cells (HUVECs). The loss of a few hundred base pairs from a shortened telomere has been shown to be important with respect to cellular senescence, although it may not be detected according to traditional mean telomere length [assessed as the terminal restriction fragment (TRF)] analyses. In the present study, a continuous time window from irradiation was selected to examine changes in the telomere length, including the mean TRF length, percentage of the telomere length, telomerase activity, apoptotic rate, and survival rate in HUVECs from the first day to the fourth day after the administration of a 0.5-Gy dose of irradiation. The mean TRF length in the irradiated HUVECs showed shorter telomere length in first 3 days, but they were not statistically significant. On the other hand, according to the percentage analysis of the telomere length, a decreasing tendency was noted in the longer telomere lengths (9.4-4.4 kb), with a significant increase in the shortest telomeres (4.4-2.3 kb) among the irradiated cells versus the controls from the first day to the third after irradiation; no significant differences were noted on the fourth day. These results suggest that the shortest telomeres are sensitive to the late stage of radiation damage. The proliferation of irradiated cells was suppressed after IR in contrast to the non-irradiated cells. The apoptotic rate was elevated initially both in IR- and non-IR-cells, but that of IR-cells was maintained at an elevated level thereafter in contrast to that of non-IR-cells decreasing promptly. Therefore, a 0.5-Gy dose of IR induces persistent apoptosis leading to an apparent growth arrest of the normal HUVECs.

Effects of bathing in different hot spring types on Japanese gut microbiota.

Hot springs have been used for a variety of purposes, including the treatment and amelioration of illness and recreation. Japan has ten different types of therapeutic springs (described here as spa types), which are traditionally believed to have different efficacy. However, more research must be conducted to determine how they affect healthy people. Therefore, this study focused on the gut microbiota and aimed to investigate changes in the gut microbiota in healthy people after bathing in different spa types. Using Beppu's hot springs (simple, chloride, bicarbonate, sulfur, and sulfate types), 136 healthy Japanese adults living in the Kyushu area participated in the study and bathed in the same hot spring for seven days. Fecal samples were collected before and after the 7-day bathing period, and the relative abundance of the gut microbiota was determined by 16S rRNA sequencing. The results showed that the relative abundance of Bifidobacterium bifidum increased significantly after seven consecutive days of bathing in the bicarbonate spring. Significant increases in other gut microbiota were also observed after bathing in simple, bicarbonate, and sulfur springs. These results suggest that bathing in different hot springs may affect the gut microbiota in healthy individuals differently.

Hyperthermia by bathing in a hot spring improves cardiovascular functions and reduces the production of inflammatory cytokines in patients with chronic heart failure.

Balneotherapy has been shown to reduce systemic blood pressure in healthy volunteers. Hyperthermia might ameliorate the inflammatory status in heart failure through improving cardiac function. The purpose of this study was to examine the beneficial effects of balneotherapy in patients with chronic heart failure (CHF). Thirty-two patients with systolic CHF classified as New York Heart Association functional status II or III were randomized to divide either a balneotherapy group or a control group. The patients in the balneotherapy group were immersed in a hot spring at 40°C for 10 min daily for 2 weeks; the control group patients took a shower daily. The left ventricular ejection fraction (EF) and cardiothoracic ratio (CTR) were evaluated and plasma brain natriuretic peptide (BNP), high-sensitivity C-reactive protein (hsCRP), tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, and IL-6 levels were measured. The clinical symptoms improved after 2 weeks of hot spring therapy. Although the heart rate did not change, clinical symptoms, CTR, EF, and BNP were significantly improved. Moreover, the inflammatory responses, including hsCRP, TNF-α and IL-6 decreased significantly after balneotherapy. The improvement of BNP correlates with the changes in inflammatory biomarkers. Repeated hyperthermia by bathing in a hot spring is therefore considered to improve the cardiac and inflammatory status in patients with CHF.

Alterations in the telomere length distribution and the subtelomeric methylation status in human vascular endothelial cells under elevated temperature in culture condition.

Temperature-associated alteration in the telomere lengths of vascular endothelial cells has not been well investigated. Telomere length of human umbilical vein endothelial cells (HUVECs) cultured at a high temperature (42 °C) was analyzed. Here described are heat-associated phenotypical alterations of human vascular endothelial cell under prolonged heat stress in terms of telomere length, telomerase activity, and the expression of telomere associated proteins and heat shock proteins. The genomic DNA extracted from HUVECs cultured for 3 days under 42 °C was digested with methylation-sensitive and -insensitive isoschizomers and was subjected to genomic Southern blot probed with a telomere DNA fragment. Their telomere lengths and telomere length distributions were analyzed. Telomerase activity and the expressions of telomere-associated RNA, telomere-associated proteins (TERC, TERT, TRF1, and TRF2), and heat shock proteins (Hsp60, Hsp70, and Hsp90) were also analyzed. At 42 °C, cell growth was suppressed and the cell senescence rate was transiently elevated. A proportional decrease in the number of long telomeres was observed transiently at 42 °C. A trend of subtelomeric hypomethylation and lowered telomerase activity were observed at 42 °C after 3-day culture. The altered phenotypes on day 1 seemed reactive responses for cell protection to heat, and those on day 3 seemed exhausted reactions after 3-day culture. Maintained expression was observed in Hsps, TRF2, and TERC. These altered phenotypes might contribute to cell-survival under prolonged heat stress.

Analysis of telomere length and subtelomeric methylation of circulating leukocytes in women with Alzheimer's disease.

BACKGROUNDS AND AIMS: Telomere attrition proceeds with the aging process, and is also associated with aging disease conditions, such as Alzheimer's disease (AD). The aging process also affects subtelomeric methylation status. In the present study, the telomere length and the subtelomeric methylation status in female AD patients were analyzed to see how AD affects telomere structure. METHODS: Terminal restriction fragment length of 23 AD patients' peripheral leukocytes was analyzed with methylation sensitive- and insensitive-isoschizomer by Southern blot. RESULTS: AD patients were found to have normal mean telomere lengths (controls; 6.4 ± 0.9 kb, AD; 6.1 ± 0.8 kb, p = 0.131), a proportionally decreased number of the longest telomeres (>9.4 kb) (controls; 30.3 ± 7.9%, AD; 24.4 ± 8.3%, p = 0.013), increased medium-sized telomeres (controls; 51.7 ± 3.3%, AD 55.5 ± 6.4%, p = 0.015) and unchanged numbers of the shortest telomeres (<4.4 kb) (controls; 18.0 ± 7.8, AD; 20.2 ± 8.9%, p = 0.371) in their peripheral leukocytes. The subtelomeres of telomeres in the shortest range (<4.4 kb) were more methylated in AD subjects than in controls (controls; 0.21 ± 0.23, AD; 0.41 ± 0.26, p = 0.016). CONCLUSIONS: These results may indicate that AD contributes to the loss of cells bearing the shortest telomeres, with hypomethylation of subtelomeres occurring in addition to telomere attrition, resulting in an apparent normal mean telomere length in AD patients. The relatively high subtelomeric methylation status of the shortest telomeres in peripheral blood leukocytes may be a characteristic of AD. This report demonstrates that the epigenetic status of the telomeric region is affected by disease conditions.

Night-Time Hot Spring Bathing Is Associated with a Lower Systolic Blood Pressure among Japanese Older Adults: A Single-Institution Retrospective Cohort Study.

Hot spring bathing is practiced to help manage hypertension. We retrospectively investigated the effects of hot spring bathing on hypertension with the aim of identifying a novel approach to prevent and manage hypertension. The study cohort comprised 99 patients aged ≥65 years admitted to Kyushu University Beppu Hospital between 1 December 2021 and 30 November 2022 who could walk by themselves and who used hot springs for ≥3 days during their hospital stay. The changes in both systolic and diastolic blood pressure were significantly decreased in the night-time bathing group (n = 21) compared with the noontime (n = 26) and afternoon (n = 52) groups. Night-time hot spring bathing was significantly associated with reduced systolic blood pressure the next morning in older adults. Although prospective randomized controlled trials on night-time hot spring bathing as a hypertension treatment are warranted to investigate whether the practice can prevent hypertension among adults aged ≥65 years, we have initiated a single-center, phase II study on the relationship between sleep quality and quality of life in hypertensive patients after night-time hot spring bathing.

Hot spring bathing practices have a positive effect on mental health in Japan.

Hot springs have long been used for medical purposes throughout the world. Recently, the positive effects of hot spa-bathing on circulatory diseases have been reported, while there are few reports on the mental effects of hot spa-bathing. Therefore, the purpose of this study was to clarify the relationship between hot spa-bathing habits and mental health throughout Japan. We conducted a nationwide online survey, including questions on bathing behavior, subjective satisfaction, lifestyle, and illness. The results showed a significant positive correlation between hot spa-bathing habits and multiple subjective satisfaction levels regarding mental health effects. The factor analysis results indicated that hot spa-bathing habits tended to be associated with good mental health, high health consciousness, and disease. Our study revealed that subjective satisfaction was higher among individuals with hot spa-bathing habits, suggesting that the hot spring spa-bathing habit may have a positive influence on mental health.

Upregulation of anticoagulant proteins, protein S and tissue factor pathway inhibitor, in the mouse myocardium with cardio-specific TNF-α overexpression.

Heart failure (HF) has been recognized as a hypercoagulable state. However, the natural anticoagulation systems in the failing heart have not been studied. Recent experimental and clinical data have indicated that not only the thrombomodulin (TM)/protein C (PC) pathway but also the protein S (PS)/tissue factor pathway inhibitor (TFPI) system function as potent natural anticoagulants. To investigate the balance between procoagulant and anticoagulant activities in the failing heart, we measured the cardiac expression of tissue factor (TF), type 1 plasminogen activator inhibitor (PAI-1), TM, PC, PS, and TFPI by RT-PCR and/or Western blot analysis in male transgenic (TG) mice with heart-specific overexpression of TNF-α. Both procoagulant (TF and PAI-1) and anticoagulant (PS and TFPI) factors were upregulated in the myocardium of 24-wk-old TG (end-stage HF) but not in that of 4-wk-old TG (early decompensated HF) compared with the wild-type mice. Both factors were also upregulated in the infarcted myocardium at 3 days after coronary ligation in the wild-type mice. The expression of TM was downregulated in the TG heart, and PC was not detected in the hearts. The transcript levels of PS orphan receptors, Mer and Tyro3, but not Axl, were significantly upregulated in the TG heart. Double immunohistochemical staining revealed that myocardial infiltrating CD3-positive T cells may produce PS in the TG myocardium. In conclusion, the PS/TFPI was upregulated in the myocardium of a different etiological model of HF, thus suggesting a role for the PS/TFPI system in the protection of the failing heart under both inflammatory and hypercoagulable states.