Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 61
Filtrar
1.
J Infect Chemother ; 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38417479

RESUMO

OBJECTIVES: Factors that affect the change of first-line antimicrobial agents were investigated to further promote their appropriate use. METHODS: This descriptive study used an electronic medical records database. Total 16,353 of the 199,896 patients enrolled between 1996 and 2019 met the inclusion criteria and formed the overall pediatric acute otitis media (AOM) cohort. The factors leading to the change in first-line antimicrobial agents within 14 days were analyzed using classification and regression trees (CART) analysis. RESULTS: This antimicrobial treatment cohort, involved 4860 cases of AOM alone and 9567 cases of AOM with other diseases. The size of the medical facility based on number of beds and historical duration of patient registration impacted on antimicrobial changes. CONCLUSIONS: The current results show that hospital-wide or nation-wide antimicrobial stewardship promotion could be the most influencing factor for antimicrobial changes. Particularly in cases of AOM where other diseases coexist, a more accurate diagnosis and definition of treatment failure of first-line drug are suggested to be important while establishing future treatment strategies. The current study is important to promote appropriate antimicrobial use for AOM treatment.

2.
Heart Vessels ; 39(1): 25-34, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37695543

RESUMO

Although angiotensin-converting enzyme inhibitors (ACEis) and angiotensin II receptor blockers (ARBs) play critical roles in the treatment of heart failure with reduced or mildly reduced ejection fraction (HFrEF/HFmrEF; left-ventricular ejection fraction ≤ 50%), the ideal timing for initiation in patients with acute heart failure (AHF) is unclear. We sought to clarify the timing and safety of ACEi/ARB prescription relative to hemodynamic stabilization (pre or post) in patients hospitalized with acute HFrEF/HFmrEF. This was a retrospective, observational analysis of electronic data of patients hospitalized for AHF at 17 Japanese hospitals. Among 9107 patients hospitalized with AHF, 2648 had HFrEF/HFmrEF, and 83.0% met the hemodynamic stabilization criteria within 10 days of admission. During hospitalization, 63.5% of patients with HFrEF/HFmrEF were prescribed an ACEi/ARB, 79.4% of which were prescribed pre-stabilization. In a multivariable analysis, patients treated with an ACEi/ARB pre-stabilization were more likely to have comorbid hypertension, diabetes mellitus, or ischemic heart disease. ACEi/ARB prescription timing was not associated with adverse events, including hypotension and renal impairment, and early prescription was associated with a lower incidence of subsequent worsening of HF. In clinical practice, more hospitalized patients with AHF received an ACEi/ARB before compared with after hemodynamic stabilization, and no safety concerns were observed. Moreover, early prescription may be associated with a lower incidence of worsening HF.


Assuntos
Inibidores da Enzima Conversora de Angiotensina , Insuficiência Cardíaca , Humanos , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Estudos Retrospectivos , Antagonistas de Receptores de Angiotensina/uso terapêutico , Volume Sistólico , Função Ventricular Esquerda
3.
Circ Rep ; 5(10): 392-402, 2023 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-37818283

RESUMO

Background: Triple combination therapy with a renin-angiotensin system modulator, a ß-blocker, and a mineralocorticoid receptor antagonist is currently recommended for patients with heart failure (HF) with reduced ejection fraction. However, there is limited evidence on the extent to which triple combination therapy is currently prescribed to patients at the time of discharge from hospital in Japan. Methods and Results: Japanese patients hospitalized for HF (n=3,582) were evaluated in subgroups defined by left ventricular ejection fraction (LVEF) using anonymized claims and electronic health record data. At discharge, triple combination therapy prescription rates were low (40.4%, 30.0%, 20.8%, 14.0%, and 12.5% for patients with LVEF <30%, 30-<40%, 40-<50%, 50-<60%, and ≥60%, respectively). Advanced age, lower levels of B-type natriuretic peptide, and renal impairment were all significantly associated with lower rates of triple combination therapy use in the overall population. There were no significant differences in rehospitalization rates between LVEF subgroups; however, triple combination therapy use was associated with a significantly reduced risk of rehospitalization for HF in patients with LVEF <30%, 30-<40%, and 40-<50%. Conclusions: The use of triple combination therapy was significantly associated with a lower risk of rehospitalization for HF within 1 year of discharge in patients with LVEF <30%, 30-<40%, and 40-<50%. However, patients were undertreated with triple combination therapy.

4.
J Am Heart Assoc ; 12(8): e027612, 2023 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-37026551

RESUMO

Background Nighttime blood pressure (BP) and an abnormal nocturnal BP dipping profile are important cardiovascular risk factors in patients with hypertension. This post hoc analysis investigated the effects of sacubitril/valsartan on 24-hour BP in patients with mild-to-moderate hypertension and in patient subgroups based on nocturnal BP dipping status. Methods and Results Data from a randomized clinical trial comparing the BP-lowering effects of 8 weeks of treatment with sacubitril/valsartan (200 or 400 mg/d) and olmesartan (20 mg/d) in Japanese patients with mild-to-moderate hypertension were analyzed. The primary end point was change in 24-hour, daytime, and nighttime BP in patient subgroups based on nocturnal BP dipping status (dipper, nondipper). Six hundred thirty-two patients with baseline and follow-up ambulatory BP data were included. Both sacubitril/valsartan dosages reduced 24-hour, daytime, and nighttime systolic BP, and 24-hour and daytime diastolic BP, to a significantly greater extent than olmesartan in the dipper and nondipper groups. However, between-group differences in nighttime systolic BP were more significant in the nondipper group (difference [95% CI] for sacubitril/valsartan 200 and 400 mg/d versus olmesartan 20 mg/d: -4.6 [95% CI, -7.3 to -1.8] and -6.8 [95% CI, -9.5 to -4.1] mm Hg, respectively; P<0.01 and P<0.001). Between-group differences in the BP control rate were greatest in the nondipper subgroup (systolic BP control rate of 34.4% and 42.6% with sacubitril/valsartan 200 and 400 mg/d versus 23.1% with olmesartan 20 mg/d). Conclusions This analysis highlights the value of sacubitril/valsartan therapy in patients with a nondipper profile of nocturnal BP and confirms this agent's potent 24-hour BP-lowering effect in Japanese populations with hypertension. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01599104.


Assuntos
Anti-Hipertensivos , População do Leste Asiático , Hipertensão , Humanos , Bloqueadores do Receptor Tipo 1 de Angiotensina II/uso terapêutico , Anti-Hipertensivos/uso terapêutico , Pressão Sanguínea , Monitorização Ambulatorial da Pressão Arterial/métodos , Hipertensão Essencial/tratamento farmacológico , Hipertensão/diagnóstico , Hipertensão/tratamento farmacológico , Hipertensão/epidemiologia , Tetrazóis/uso terapêutico , Valsartana/uso terapêutico
5.
DEN Open ; 3(1): e181, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36310664

RESUMO

A 36-year-old woman visited our hospital with a chief complaint of bleeding during defecation. Colonoscopy revealed a 20-mm pedunculated polyp in the sigmoid colon, which was en bloc resected under endoscopy. The histopathological diagnosis was adenoma cancer with a depth of invasion indicating mucosal cancer, no lymphovascular invasion, and negative at the resection margin. The poorly differentiated adenocarcinoma component comprised approximately 5% of the tumor. Although there were no recurrence signs in the computed tomography scans obtained 4 months post polypectomy, the patient experienced aggressive lower back pain at 6 months post polypectomy. Local recurrence, peritoneal dissemination, and liver metastasis were confirmed. Finally, the patient died following a rapid and aggressive deterioration of her general condition. Histological examination of the local recurrence revealed a poorly differentiated adenocarcinoma (por2), with immunostaining revealing a high Ki67 positivity rate of 95%. Moreover, the poorly differentiated adenocarcinoma region of the resected polyp had a Ki67 positivity rate of 90%, which suggested that they were the same tumors. These findings suggested that the recurrence could have occurred through implantation.

6.
Drugs Real World Outcomes ; 9(3): 377-389, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35753032

RESUMO

BACKGROUND: Repeated hospitalization is a predictor of outcomes in heart failure, indicating the presence of symptoms, a deteriorated condition at pre-admission, and worsened prognosis. OBJECTIVES: The current database study aimed to understand the clinical and economic burden of repeated hospitalizations among patients with heart failure in Japan. The effect of repeated hospitalizations on the subsequent in-hospital mortality was the primary objective; economic burden of heart failure after discharge was investigated as a secondary outcome. METHODS: Between 2013 and 2018, administrative claims and discharge summary data of patients aged ≥ 20 years and diagnosed with heart failure were obtained from a Diagnosis Procedure Combination database maintained by Medical Data Vision. Hospitalization, mortality, and economic burden data were analyzed. RESULTS: This study included 49,094 patients. The mean length of the first hospital stay was 22.9 days. The in-hospital mortality rate was approximately 10%, with one to five repeated hospitalizations. The time interval between repeated hospitalizations for heart failure decreased with an increasing number of hospitalizations. In-hospital mortality did not increase even with an increasing number of hospitalizations. The mean heart failure-related healthcare cost per patient was ¥564,281 ± 990,447 (US$5178 ± 9,088), 67.3% of which was hospitalization costs. Among hospitalization costs, other costs were high, mainly for basic hospitalization fees (71.7%; ¥233,146/person-year). CONCLUSIONS: Repeated hospitalization did not increase in-hospital mortality; however, it may shorten the intervals between heart failure-related hospitalizations, potentially caused by deterioration of the patient's condition, and increase the clinical and economic burden on patients.

9.
Circ Rep ; 2(12): 722-729, 2020 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-33693202

RESUMO

Background: We investigated the impact of heart failure (HF) on daily life and satisfaction with current HF medication from the patient perspective in a real-world study in Japan. Methods and Results: A cross-sectional survey of 154 HF patients treated by 58 cardiologists was conducted in Japan using patient self-completed questionnaires about their daily life and satisfaction with HF medication, as well as patient record forms completed by their physicians capturing corresponding data. The mean age of patients was 72.7 years. The proportion of patients within New York Heart Association Class I, II, III, and IV was 39%, 44%, 16%, and 1%, respectively. Symptoms reported by patients included dyspnea when active (46%), nocturia (43%), anxiety (18%), and depression (6%). There was a discordance between physician- and patient-reported symptoms, especially for nocturia and inability to sleep. The most frequent lifestyle recommendation from physicians was 'reduce salt/sodium intake', but only 51% of patients receiving this recommendation followed the advice. In all, 44% of patients reported dissatisfaction with their current medication; according to the patients, 27% reported no discussion with their physicians about their prescribed medication, while physicians reported the opposite. Conclusions: HF negatively impacts patient daily life. There is discordance between patients and physicians in symptom reporting, lifestyle modification advice and adherence, and reported medication decision making. Gaps in patient-physician communication exist.

10.
Leukemia ; 34(4): 1125-1134, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31728056

RESUMO

Accumulation of DNA damage and myeloid-skewed differentiation characterize aging of the hematopoietic system, yet underlying mechanisms remain incompletely understood. Here, we show that aging hematopoietic progenitor cells particularly of the myeloid branch exhibit enhanced resistance to bulky DNA lesions-a relevant type of DNA damage induced by toxins such as cancer drugs or endogenous aldehydes. We identified aging-associated activation of the Hedgehog (Hh) pathway to be connected to this phenotype. Inhibition of Hh signaling reverts DNA damage tolerance and DNA damage-resistant proliferation in aged hematopoietic progenitors. Vice versa, elevating Hh activity in young hematopoietic progenitors is sufficient to impair DNA damage responses. Altogether, these findings provide experimental evidence for aging-associated increases in Hh activity driving DNA damage tolerance in myeloid progenitors and myeloid-skewed differentiation. Modulation of Hh activity could thus be explored as a therapeutic strategy to prevent DNA damage tolerance, myeloid skewing, and disease development in the aging hematopoietic system.


Assuntos
Envelhecimento , Diferenciação Celular , Dano ao DNA , Proteínas Hedgehog/metabolismo , Hematopoese , Células-Tronco Hematopoéticas/patologia , Animais , Apoptose , Proliferação de Células , Células Cultivadas , Feminino , Células-Tronco Hematopoéticas/efeitos dos fármacos , Células-Tronco Hematopoéticas/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Alcaloides de Veratrum/farmacologia
11.
Diabetol Metab Syndr ; 11: 90, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31695754

RESUMO

BACKGROUND: Guidelines for Type 2 diabetes mellitus (T2DM) management in Japan provide physicians the discretion to select treatment options based on patient pathophysiology of the disease. There exists a wide variation of preference for initial antidiabetes drugs (AD). The current database analysis aimed to understand the real world treatment patterns in drug-naive patients with T2DM in Japan. METHODS: We analyzed data of patients (≥ 18 years) diagnosed with T2DM between October 2012 and September 2016 from the Medical Data Vision, a Diagnosis Procedure Combination database. The primary objective was to determine the proportion of T2DM patients receiving each type of treatment as first-line therapy among the drug-naive cohort. RESULTS: Of the 436,546 drug-naive patients, 224,761 received their first-line T2DM treatment in the outpatient setting. The mean age of the patient population was 65.6 years at index date. Dipeptidyl peptidase-4 (DPP-4) inhibitor was the most prescribed (56.8%) outpatient AD monotherapy, followed by metformin (15.4%). DPP-4 inhibitors were prescribed over metformin in patients with renal disease (odds ratio [OR]: 4.20; p < 0.0001), coronary heart disease and stroke (OR: 2.22; p < 0.0001). Male (OR: 1.03; p = 0.0026), presence of diabetic complications [retinopathy (OR: 1.33; p < 0.0001), neuropathy (OR: 1.05; p = 0.0037), nephropathy (OR: 1.08; p < 0.0001)] and a high baseline HbA1c (OR: 1.45; p < 0.0001) received treatment intensification during 180 days. CONCLUSION: DPP-4 inhibitors were the most prevalent first-line T2DM treatment followed by metformin in Japan. The findings from this retrospective analysis also support the previously published web survey results and can help understand the real world utilization of T2DM treatment.Trial registration Retrospectively registered.

12.
Immunol Cell Biol ; 97(6): 586-596, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30875134

RESUMO

The peripheral maturation of human CD1d-restricted natural killer T (NKT) cells has not been well described. In this study, we identified four major subsets of NKT cells in adults, distinguished by the expression of CD4, CD8 and CCR5. Phenotypic analysis suggested a hierarchical pattern of differentiation, whereby immature CD4+ CD8- CCR5- cells progressed to an intermediate CD4+ CD8- CCR5+ stage, which remained less differentiated than the CD4- CD8- and CD4- CD8+ subsets, both of which expressed CCR5. This interpretation was supported by functional data, including clonogenic potential and cytokine secretion profiles, as well as T-cell receptor (TCR) excision circle analysis. Moreover, conventional and high-throughput sequencing of the corresponding TCR repertoires demonstrated significant clonotypic overlap within individuals, especially between the more differentiated CD4- CD8- and CD4- CD8+ subsets. Collectively, these results mapped a linear differentiation pathway across the post-thymic landscape of human CD1d-restricted NKT cells.


Assuntos
Subpopulações de Linfócitos/imunologia , Células T Matadoras Naturais/imunologia , Receptores de Antígenos de Linfócitos T/genética , Antígenos CD1d/metabolismo , Antígenos CD4/metabolismo , Antígenos CD8/metabolismo , Diferenciação Celular , Células Cultivadas , Células Clonais , Citocinas/metabolismo , Citometria de Fluxo , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Imunofenotipagem , Receptores CCR5/metabolismo
13.
Nat Cell Biol ; 21(6): 791-792, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30808996

RESUMO

In the version of this Article originally published, the authors mistakenly used the same images for the Fig. 2d Per-/- upper Merge, DAPI and p-RPA2 (Ser33), and Fig. 3e upper 2 months, WT Per2 DAPI and Merge panels. The correct images from these experiments, and their correctly sized scale bars, are shown below. In addition, the full dataset of representative images for Figs 2d and 3e, and the numerical source data of the corresponding quantifications of Figs 2c and 3f, have been uploaded to Figshare ( https://doi.org/10.6084/m9.figshare.c.4353791.v1 ). In addition, the Methods section did not provide sufficient detail on how immunoblot experiments were conducted. Western blots were repeated three times using the antibodies stated in the Methods. PER2 blots were obtained using the PER2 antibody (Millipore, AB2202); except in the PER2 blots in the Repeat 1 experiments corresponding to Fig. 3g and 3k, where the PER2 antibody from BD Transduction (611138) was used. Repeats 1 and 2 were imaged using ECL and LI-COR methods, and Repeat 3 only used the LI-COR system. The images presented in the paper were from Repeat 3 and were stored electronically and as printouts, however the electronic versions were cropped as depicted in Supplementary Fig. 6. Repeat 1 images were stored electronically and Repeat 2 images only as printouts. In addition - with the exception of Figs 2g (ATM), 3g (PER2, Repeat 1A), 3k (PER2, PUMA, p21, BAX, BCL2) and Supplementary Fig. 1a of Repeat 1, in which actin immunoblots were loading controls processed from the same membranes used to detect the target proteins - in all other cases the actin blots were sample processing controls that were run in parallel using the same lysates and loading concentrations that were used for the detection of the target proteins. The electronic images from Repeat 1 and the printout images of Repeats 2 and 3 have been uploaded to Figshare ( https://doi.org/10.6084/m9.figshare.c.4353791.v1 ). Finally, there is an error in the protein size label of the p-CHK1 blot of Fig. 2f and the corresponding blot in Supplementary Fig. 6, which should read '55KD' instead of '50KD'.

14.
J Exp Med ; 216(1): 152-175, 2019 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-30530755

RESUMO

Organism aging is characterized by increased inflammation and decreased stem cell function, yet the relationship between these factors remains incompletely understood. This study shows that aged hematopoietic stem and progenitor cells (HSPCs) exhibit increased ground-stage NF-κB activity, which enhances their responsiveness to undergo differentiation and loss of self-renewal in response to inflammation. The study identifies Rad21/cohesin as a critical mediator of NF-κB signaling, which increases chromatin accessibility in the vicinity of NF-κB target genes in response to inflammation. Rad21 is required for normal differentiation, but limits self-renewal of hematopoietic stem cells (HSCs) during aging and inflammation in an NF-κB-dependent manner. HSCs from aged mice fail to down-regulate Rad21/cohesin and inflammation/differentiation signals in the resolution phase of inflammation. Inhibition of cohesin/NF-κB reverts hypersensitivity of aged HSPCs to inflammation-induced differentiation and myeloid-biased HSCs with disrupted/reduced expression of Rad21/cohesin are increasingly selected during aging. Together, Rad21/cohesin-mediated NF-κB signaling limits HSPC function during aging and selects for cohesin-deficient HSCs with myeloid-skewed differentiation.


Assuntos
Envelhecimento/imunologia , Proteínas de Ciclo Celular/imunologia , Proliferação de Células , Proteínas Cromossômicas não Histona/imunologia , Células-Tronco Hematopoéticas/imunologia , NF-kappa B/imunologia , Transdução de Sinais/imunologia , Envelhecimento/genética , Animais , Proteínas de Ciclo Celular/genética , Proteínas Cromossômicas não Histona/genética , Proteínas de Ligação a DNA , Inflamação/genética , Inflamação/imunologia , Camundongos , Camundongos Knockout , NF-kappa B/genética , Proteínas Nucleares/genética , Proteínas Nucleares/imunologia , Fosfoproteínas/genética , Fosfoproteínas/imunologia , Transdução de Sinais/genética , Coesinas
17.
Nucleic Acids Res ; 44(13): 6252-61, 2016 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-27137888

RESUMO

Reduced capacity of genome maintenance represents a problem for any organism, potentially causing premature death, carcinogenesis, or accelerated ageing. Strikingly though, loss of certain genome stability factors can be beneficial, especially for the maintenance of tissue stem cells of the intestine and the haematopoietic system. We therefore screened for genome stability factors negatively impacting maintenance of haematopoietic stem cells (HSC) in the context of ionising radiation (IR). We found that in vivo knock down of Xeroderma pigmentosum, complementation group G (Xpg) causes elevation of HSC numbers after IR treatment, while numbers of haematopoietic progenitors are elevated to a lesser extent. IR rapidly induces Xpg both on mRNA and on protein level. Prevention of this induction does not influence activation of the checkpoint cascade, yet attenuates late checkpoint steps such as induction of p21 and Noxa. This causes a leaky cell cycle arrest and lower levels of apoptosis, both contributing to increased colony formation and transformation rates. Xpg thus helps to adequately induce DNA damage responses after IR, thereby keeping the expansion of damaged cells under control. This represents a new function of Xpg in the response to IR, in addition to its well-characterized role in nucleotide excision repair.


Assuntos
Carcinogênese/efeitos da radiação , Reparo do DNA/genética , Proteínas de Ligação a DNA/biossíntese , Endonucleases/biossíntese , Instabilidade Genômica/efeitos dos fármacos , Células-Tronco Hematopoéticas/efeitos da radiação , Proteínas Nucleares/biossíntese , Fatores de Transcrição/biossíntese , Apoptose/efeitos da radiação , Pontos de Checagem do Ciclo Celular/efeitos da radiação , Dano ao DNA/efeitos da radiação , Proteínas de Ligação a DNA/genética , Endonucleases/genética , Regulação da Expressão Gênica/efeitos da radiação , Técnicas de Silenciamento de Genes , Instabilidade Genômica/efeitos da radiação , Humanos , Proteínas Nucleares/genética , RNA Mensageiro/biossíntese , Radiação Ionizante , Fatores de Transcrição/genética , Xeroderma Pigmentoso/genética
18.
Nat Cell Biol ; 18(5): 480-90, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-27088856

RESUMO

Ageing-associated impairments in haemato-lymphopoiesis are associated with DNA damage accumulation and reduced maintenance of lymphoid-biased (Ly-biased) compared with myeloid-biased (My-biased) haematopoietic stem cells (HSCs). Here, in vivo RNAi screening identifies period circadian clock 2 (Per2) as a critical factor limiting the maintenance of HSCs in response to DNA damage and ageing. Under these conditions, Per2 is activated predominantly in Ly-biased HSCs and stimulates DNA damage signalling and p53-dependent apoptosis in haematopoietic cells. Per2 deletion ameliorates replication stress and DNA damage responses in haematopoietic cells, thereby improving the maintenance of Ly-biased HSCs, lymphopoiesis, and immune function in ageing mice without increasing the accumulation of DNA damage. Per2-deficient mice retain Batf/p53-dependent induction of differentiation of HSCs in response to DNA damage and exhibit an elongated lifespan. Together, these results identify Per2 as a negative regulator of Ly-biased HSCs and immune functions in response to DNA damage and ageing.


Assuntos
Senescência Celular , Dano ao DNA , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Linfócitos/citologia , Linfopoese , Proteínas Circadianas Period/metabolismo , Envelhecimento/metabolismo , Animais , Apoptose , Fator Ativador de Células B/metabolismo , Western Blotting , Diferenciação Celular , Separação Celular , Replicação do DNA , Imunofluorescência , Deleção de Genes , Transplante de Células-Tronco Hematopoéticas , Homozigoto , Imunidade , Camundongos Knockout , Estresse Fisiológico , Encurtamento do Telômero , Proteína Supressora de Tumor p53/metabolismo , Regulação para Cima
19.
J Exp Med ; 213(4): 535-53, 2016 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-26951333

RESUMO

Dietary restriction (DR) improves health, delays tissue aging, and elongates survival in flies and worms. However, studies on laboratory mice and nonhuman primates revealed ambiguous effects of DR on lifespan despite improvements in health parameters. In this study, we analyzed consequences of adult-onset DR (24 h to 1 yr) on hematopoietic stem cell (HSC) function. DR ameliorated HSC aging phenotypes, such as the increase in number of HSCs and the skewing toward myeloid-biased HSCs during aging. Furthermore, DR increased HSC quiescence and improved the maintenance of the repopulation capacity of HSCs during aging. In contrast to these beneficial effects, DR strongly impaired HSC differentiation into lymphoid lineages and particularly inhibited the proliferation of lymphoid progenitors, resulting in decreased production of peripheral B lymphocytes and impaired immune function. The study shows that DR-dependent suppression of growth factors and interleukins mediates these divergent effects caused by DR. Supplementation of insulin-like growth factor 1 partially reverted the DR-induced quiescence of HSCs, whereas IL-6/IL-7 substitutions rescued the impairment of B lymphopoiesis exposed to DR. Together, these findings delineate positive and negative effects of long-term DR on HSC functionality involving distinct stress and growth signaling pathways.


Assuntos
Envelhecimento/imunologia , Restrição Calórica , Diferenciação Celular/imunologia , Senescência Celular/imunologia , Células-Tronco Hematopoéticas/imunologia , Células Progenitoras Linfoides/imunologia , Linfopoese/imunologia , Animais , Células-Tronco Hematopoéticas/citologia , Células Progenitoras Linfoides/citologia , Camundongos , Camundongos Knockout
20.
J Theor Biol ; 394: 57-67, 2016 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-26802482

RESUMO

The transplantation of blood tissues from bone marrow into a lethally irradiated animal is an experimental procedure that is used to study how the blood system is reconstituted by haematopoietic stem cells (HSC). In a competitive repopulation experiment, a lethally irradiated mouse was transplanted with a single HSC as a test cell together with a number of bone marrow cells as competitor cells, and the fraction of the test cell progeny (percentage of chimerism) was traced over time. In this paper, we studied the stem cell kinetics in this experimental procedure. The balance between symmetric self-renewal and differentiation divisions in HSC determined the number of cells which HSC produce and the length of time for which HSC live after transplantation. The percentage of chimerism depended on the type of test cell (long-, intermediate-, or short-term HSC), as well as the type and number of HSC included in competitor cells. We next examined two alternative HSC differentiation models, one-step and multi-step differentiation models. Although these models differed in blood cell production, the percentage of chimerism appeared very similar. We also estimated the numbers of different types of HSC in competitor cells. Based on these results, we concluded that the experimental results inevitably include stochasticity with regard to the number and the type of HSC in competitor cells, and that, in order to detect different types of HSC, an appropriate number of competitor cells needs to be used in transplantation experiments.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/citologia , Animais , Diferenciação Celular , Proliferação de Células , Simulação por Computador , Camundongos , Modelos Biológicos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...