Gerontología: un mirada bibliométrica de las citaciones clásicas en Web Of Science (1975-2018) / Gerontology: a bibliometric look at classical citations in Web Of Science (1975-2018)

Resumen La gerontología es comprendida como un enfoque interdisciplinario que aborda el proceso de envejecimiento y vejez. El presente artículo caracteriza la evolución de la investigación en el campo gerontológico durante los últimos 44 años a través de un análisis bibliométrico de los trabajos de mayor impacto en el área. Se revisaron 94 publicaciones de la colección principal de la Web of Science (WoS) de Thomson Reuters en el periodo 1975-2018. Se analizan las publicaciones y su evolución longitudinal, el acoplamiento de documentos clásicos, áreas de investigación, autores y co-autorías, revistas y países. Se concluye que Estados Unidos es el país que reúne la mayor cantidad de publicaciones, citas y revistas de difusión de textos clásicos.

Abstract Gerontology is understood as an interdisciplinary approach that addresses the process of aging and old age. The present article characterizes the evolution of research in the gerontological field during the last 44 years through a bibliometric analysis of the works of greatest impact in the area. Ninety-four publications were reviewed from the main collection of the Web of Science (WoS) by Thomson Reuters in the period 1975-2018. The publications and their longitudinal evolution, the coupling of classic documents, research areas, authors and co-authors, journals and countries are analyzed. It is concluded that the United States is the country with the largest number of publications, citations and journals disseminating classical texts.

Evidencias psicométricas iniciales de la escala de autoeficacia para envejecer (EAEE) en adultos mayores peruanos / Evidence psychometric initial of the scale of self-efficacy for aging (EAEE) in peruvian elderly

Resumen El estudio examina las evidencias psicométricas de la Escala de Autoeficacia para Envejecer (EAEE) en una muestra de 400 adultos mayores (75.2% mujeres y 24.8% hombres) de la ciudad de Trujillo (Perú) con una edad promedio de 73.37 años (DE = 7.86). Los participantes completaron la EAEE junto con medidas de satisfacción con la vida y depresión. El análisis factorial exploratorio (AFE), reveló que la EAEE presentaba una estructura factorial unidimensional. El análisis factorial confirmatorio (AFC), mostró que el modelo unidimensional tenía un ajuste aceptable (S-Bχ2 = 54.02, df = 345 p = .001; S-Bχ2/df = 1.54; CFI = .97; RMSEA = .052 [IC90% .021, .078]; y SRMR = .049; AIC= 118.96) y una confiabilidad adecuada (ω = .88 [IC95% .84 - .91]; α = .88 [IC95%: .84 - .91]). Los puntajes de la EAEE se correlacionaron de manera positiva con la satisfacción con la vida (r = .56, p< .01 [IC95%: .46, .79]) y negativa con la depresión (r = -.48, p< .01 [IC95%: -.37, -.73]). Los resultados sugieren que la EAEE presenta evidencias de validez basada en la estructura interna, convergente y discriminante, así como una adecuada confiabilidad.

Abstract The study examines the psychometric evidences of the Self-Efficacy Scale for Aging (EAEE) in a sample of 400 older adults (75.2% women and 24.8% men) from the city of Trujillo (Peru) with an average age of 73.37 years (DE = 7.86). The participants completed the EAEE along with measures of life satisfaction and depression. The exploratory factor analysis (AFE) revealed that the EAEE presented a one-dimensional factorial structure. The confirmatory factor analysis (CFA) showed that the one-dimensional model had an acceptable fit (S-Bχ2 = 54.02, df = 345 p = .001; S-Bχ2/df = 1.54; CFI = .97; RMSEA = .052 [IC90% .021, .078]; y SRMR = .049; AIC= 118.96) and an adequate reliability (ω = .88 [IC95% .84 - .91]; α = .88 [IC95%: .84 - .91]). EAEE scores correlated positively with satisfaction with life (r = .56, p< .01 [IC95%: .46, .79]) and negative with depression (r = -.48, p< .01 [IC95%: -.37, -.73]). The results suggest that the EAEE presents evidence of validity based on the internal structure, convergent and discriminant, as well as an adequate reliability.

Viral infections during pregnancy.

Viral infections during pregnancy have long been considered benign conditions with a few notable exceptions, such as herpes virus. The recent Ebola outbreak and other viral epidemics and pandemics show how pregnant women suffer worse outcomes (such as preterm labor and adverse fetal outcomes) than the general population and non-pregnant women. New knowledge about the ways the maternal-fetal interface and placenta interact with the maternal immune system may explain these findings. Once thought to be 'immunosuppressed', the pregnant woman actually undergoes an immunological transformation, where the immune system is necessary to promote and support the pregnancy and growing fetus. When this protection is breached, as in a viral infection, this security is weakened and infection with other microorganisms can then propagate and lead to outcomes, such as preterm labor. In this manuscript, we review the major viral infections relevant to pregnancy and offer potential mechanisms for the associated adverse pregnancy outcomes.

Viral infection of the pregnant cervix predisposes to ascending bacterial infection.

Preterm birth is the major cause of neonatal mortality and morbidity, and bacterial infections that ascend from the lower female reproductive tract are the most common route of uterine infection leading to preterm birth. The uterus and growing fetus are protected from ascending infection by the cervix, which controls and limits microbial access by the production of mucus, cytokines, and antimicrobial peptides. If this barrier is compromised, bacteria may enter the uterine cavity, leading to preterm birth. Using a mouse model, we demonstrate, to our knowledge for the first time, that viral infection of the cervix during pregnancy reduces the capacity of the female reproductive tract to prevent bacterial infection of the uterus. This is due to differences in susceptibility of the cervix to infection by virus during pregnancy and the associated changes in TLR and antimicrobial peptide expression and function. We suggest that preterm labor is a polymicrobial disease, which requires a multifactorial approach for its prevention and treatment.

Modulation and recruitment of inducible regulatory T cells by first trimester trophoblast cells.

PROBLEM The specialized regulatory T-cells (Treg) population, essential for maternal tolerance of the fetus, performs its suppressive actions in the critical peri-implantation phase of pregnancy. In the present work, we investigated whether trophoblast cells are able to induce Treg recruitment, differentiation, and whether these mechanisms are modified by a bacterial or viral infection. METHOD OF STUDY Human T-regulatory cells were differentiated from naïve CD45RA(+) CCR7(+) cells obtained from peripheral blood mononuclear cells cultured with IL-2 and TGFß over 5 days. Induction of iTregs (CD4(+) Foxp3(+) cells) was evaluated using low serum conditioned media (LSCM), obtained from two first trimester trophoblast cell lines, Swan-71 and HTR8. Coculture experiments were carried out using transwell assays where trophoblast cells were in the absence or presence of PGN, LPS, or Poly [I:C]. Cytokine production was measured by multiplex analysis. RESULTS Trophoblast cells constitutively secrete high levels of TGFß and induced a significant increase of Foxp3 expression accompanied by a specific T-reg cytokine profile. Moreover, trophoblast cells were able to recruit iTregs in a specific manner. CONCLUSION We demonstrate that trophoblast cells have an active role on the recruitment and differentiation of iTregs, therefore, contributing to the process of immune regulation at the placental-maternal interface.

Knockdown of Hoxa11 in vivo in the uterosacral ligament and uterus of mice results in altered collagen and matrix metalloproteinase activity.

Homeobox (HOX) genes are evolutionarily conserved genes encoding transcription factors that regulate mammalian embryonic growth and development of the urogenital tract. In both humans and mice, HOXA11 persists in the adult reproductive tract and is thought to play an important role in maintaining tissue developmental plasticity by regulating the expression of genes involved in extracellular matrix metabolism in the reproductive organs. Previously, we have shown that HOXA11 is necessary for development of the uterosacral ligaments in mice and is deficient in women with pelvic organ prolapse. Therefore, we hypothesized that Hoxa11 regulates the synthesis and/or metabolism of collagens in the uterosacral ligaments and uterus, and tested this by establishing an in utero and peritoneal Hoxa11 gene knockdown system in C57/BL6 mice using vectors bearing Hoxa11 short hairpin RNA. Specific knockdown of Hoxa11 transcripts and protein levels were confirmed versus control vectors. Protein and mRNA expression of collagen types I and III exhibited significant decreases following Hoxa11 knockdown according to Western blot analysis and real-time PCR. Tissue inhibitor of matrix metalloproteinase 1 (MMP1) expression also exhibited a significant decrease. Gelatinase zymography confirmed increases in pro-MMP2 and MMP9, as well as activated MMP2, following Hoxa11 knockdown. These results reveal that Hoxa11 knockdown in the uterosacral ligaments and uterus increases extracellular matrix degradation. More importantly, it suggests a mechanism in the weakening of the pelvic floor support in women, because decreased HOXA11 gene expression has been reported to be associated with decreased collagen and increased MMP2 expression in the uterosacral ligaments of women with pelvic organ prolapse.

Toll-like receptor-3 ligation-induced indoleamine 2, 3-dioxygenase expression in human trophoblasts.

Indoleamine 2,3-dioxygenase (IDO) is an enzyme that degrades an essential amino acid, tryptophan, and plays a role in inhibiting the proliferation of T cells and intracellular pathogens. Inhibiting IDO in mice leads to fetal rejection, suggesting its significance in establishing pregnancy. Toll-like receptor 3 (TLR-3) is a key component of the innate immune system that recognizes viral double-stranded RNA and triggers immune reactions by producing type I interferon. Using a human trophoblast cell culture system, we studied the effect of TLR-3 ligation on IDO expression and function by treating trophoblasts with polyinosinic-polycytidylic acid [poly(I:C)] (a synthetic double stranded RNA, which mimics viral RNA). Real-time PCR and Western blot analysis revealed that IDO mRNA and protein expression was significantly induced by poly(I:C). The activity of IDO was also increased by poly(I:C) given that the L-kynurenine concentrations were elevated in conditioned media. Conditioned media from poly(I:C)-treated trophoblasts were found to inhibit the proliferation of human T cells significantly. Poly(I:C) was also shown to induce interferon (IFN)-ß mRNA expression in trophoblasts. Recombinant human IFN-ß increased IDO mRNA expression in trophoblasts more rapidly than poly(I:C). Pretreating with neutralizing antibody against IFN-ß significantly suppressed IDO induction by poly(I:C). Collectively we have demonstrated that ligation of TLR-3 by poly(I:C) induces IDO expression in human first-trimester trophoblasts via an IFN-ß-dependent pathway. These findings suggest that upon viral infection, trophoblasts induce IDO and in turn contribute to antimicrobial activity and maintenance of fetomaternal tolerance.

Nod1 activation by bacterial iE-DAP induces maternal-fetal inflammation and preterm labor.

There is a strong association between infection and prematurity; however, the underlying mechanisms remain largely unknown. Nod1 and Nod2 are intracellular pattern recognition receptors that are activated by bacterial peptides and mediate innate immunity. We previously demonstrated that human first-trimester trophoblasts express Nod1 and Nod2, which trigger inflammation upon stimulation. This study sought to determine the expression and function of Nod1 and Nod2 in third-trimester trophoblasts, and to characterize the in vivo effects of Nod1 activation on pregnancy outcome. Human term placental tissues and isolated term trophoblast expressed Nod1, but not Nod2. Activation of Nod1 by its agonist, bacterial γ-D-glutamyl-meso-diaminopimelic acid (iE-DAP), in term trophoblast cultures induced a proinflammatory cytokine profile, characterized by elevated levels of secreted IL-6, GRO-α, and MCP-1, when compared with the control. However, these cytokines were not upregulated in response to Nod2 stimulation with bacterial MDP. Administration of high-dose bacterial iE-DAP to pregnant C57BL/6J mice on embryonic day 14.5 triggered preterm delivery within 24 h. iE-DAP at a lower dose that did not induce prematurity, reduced fetal weight, altered the cytokine profile at the maternal-fetal interface, and induced fetal inflammation. Thus, functional Nod1 is expressed by trophoblast cells across gestation and may have a role in mediating infection-associated inflammation and prematurity. This study demonstrates that pattern recognition receptors, other than the TLRs, may be implicated or involved in infection-associated preterm labor.

Inflammation and pregnancy: the role of the immune system at the implantation site.

The concept that pregnancy is associated with immune suppression has created a myth of pregnancy as a state of immunological weakness and, therefore, of increased susceptibility to infectious diseases. A challenging question is whether the maternal immune system is a friend or a foe of pregnancy. In this review, we discuss data associated to the role of the immune system during pregnancy. We propose a new paradigm in terms of the fetal-maternal immune interaction as well as the immunological response of the mother to microorganism. Our challenge is to better understand the immunology of pregnancy in order to deliver the appropriate treatment to patients with pregnancy complications as well as to determine public policies for the protection of pregnant women during pandemics.

Placental viral infection sensitizes to endotoxin-induced pre-term labor: a double hit hypothesis.

PROBLEM: Among pregnant women, acquired viral infections with a concurrent bacterial infection is a detrimental factor associated to poor prognosis. We evaluate the effect of a viral infection that does not lead to pre-term labor on the response to low doses of lipopolysaccharide (LPS). Our objectives were (i) to characterize the effect of a viral infection concurrent with exposure to microbial products on pregnancy outcome and (ii) to characterize the placental and fetal immune responses to the viral sensitization to LPS. METHOD: C57B/6 wild-type mice were injected with murine gammaherpesvirus 68 (MHV68) at E8.5. Either PBS or LPS was injected i.p. at E15.5. Pregnancy outcome and cytokine/chemokine profile from implantation sites were analyzed by multiplex. RESULTS: LPS treatment of MHV-68-infected animals induced pre-term delivery and fetal death in 100% of the mice. Pre-term labor was characterized by a upregulation of pro-inflammatory cytokines and chemokines in both placenta and decidua. Similar profiles were observed from MHV-68-infected human primary trophoblast and trophoblast cell lines in response to LPS. CONCLUSION: We describe for the first time that a sub-clinical viral infection in pregnant mice might sensitize to a bacterial infection leading to pre-term delivery. We propose the 'Double Hit Hypothesis' where the presence of a viral infection enhances the effect of bacterial products during pregnancy leading not only to pre-term labor but likely larger adverse outcomes.

Viral infection of the placenta leads to fetal inflammation and sensitization to bacterial products predisposing to preterm labor.

Pandemics pose a more significant threat to pregnant women than to the nonpregnant population and may have a detrimental effect on the well being of the fetus. We have developed an animal model to evaluate the consequences of a viral infection characterized by lack of fetal transmission. The experiments described in this work show that viral infection of the placenta can elicit a fetal inflammatory response that, in turn, can cause organ damage and potentially downstream developmental deficiencies. Furthermore, we demonstrate that viral infection of the placenta may sensitize the pregnant mother to bacterial products and promote preterm labor. It is critical to take into consideration the fact that during pregnancy it is not only the maternal immune system responding, but also the fetal/placental unit. Our results further support the immunological role of the placenta and the fetus affecting the global response of the mother to microbial infections. This is relevant for making decisions associated with treatment and prevention during pandemics.

The immune system in pregnancy: a unique complexity.

Placental immune response and its tropism for specific viruses and pathogens affect the outcome of the pregnant woman's susceptibility to and severity of certain infectious diseases. The generalization of pregnancy as a condition of immune suppression or increased risk is misleading and prevents the determination of adequate guidelines for treating pregnant women during pandemics. There is a need to evaluate the interaction of each specific pathogen with the fetal/placental unit and its responses to design the adequate prophylaxis or therapy. The complexity of the immunology of pregnancy and the focus, for many years, on the concept of immunology of pregnancy as an organ transplantation have complicated the field and delayed the development of new guidelines with clinical implications that could help to answer these and other relevant questions. Our challenge as scientists and clinicians interested in the field of reproductive immunology is to evaluate many of the 'classical concepts' to define new approaches for a better understanding of the immunology of pregnancy that will benefit mothers and fetuses in different clinical scenarios.

Phagocytosis of apoptotic trophoblast cells by human endometrial endothelial cells induces proinflammatory cytokine production.

PROBLEM: Apoptosis is a normal constituent of trophoblast turnover in the placenta; however in some cases, this process is related to pregnancy complications such as preeclampsia. Recognition and engulfment of these apoptotic trophoblast cells is important for clearance of dying cells. The aim of this study was to show the cross talk between human endometrial endothelial cells (HEECs) and apoptotic trophoblast cells in an in vitro coculture model and its effect on cytokine production by HEECs. METHOD OF STUDY: Fluorescent-labeled HEECs were cocultured with fluorescent-labeled apoptotic human trophoblast cells. Confocal microscopy and flow cytometry were used to show the interaction between these two types of cells. Cytokine profiles were determined using multiplex analysis. RESULTS: HEECs are capable to phagocytose apoptotic trophoblasts. This activity is inhibited by the phagocytosis inhibitor cytochalasin B. Phagocytosis of apoptotic trophoblast cells induced the secretion of the proinflammatory cytokines interleukin-6 and monocyte chemoattractant protein-1 by HEECs. CONCLUSION: This study provides the first evidence that HEECs have an ability to phagocytose apoptotic trophoblasts. Furthermore, we demonstrated an inflammatory response of HEECs after phagocytosing the apoptotic trophoblast cells. This event may contribute to the inflammatory response in both normal pregnancy and pathologic pregnancy such as preeclampsia.

Regulation of Nod1 and Nod2 in first trimester trophoblast cells.

PROBLEM: The cytoplasmic pattern recognition receptors, Nod1 and Nod2, are thought to be important for detecting intracellular bacteria. We have previously reported that first trimester trophoblast cells express Nod1 and Nod2, and that trophoblast Nod2 activation triggers an inflammatory response. The objectives of this study were to characterize the effects of Nod1 stimulation, and to determine the regulation of Nod1 and Nod2, in the trophoblast. METHOD OF STUDY: The effect of Nod1 activation on trophoblast cells was determined by analyzing the cytokine response following treatment with gamma-D-glutamyl-meso-diaminopimelic acid (iE-DAP). The regulation of Nod1 and Nod2 expression by trophoblast cells was evaluated by RT-PCR. RESULTS: Treatment of trophoblast cells with iE-DAP significantly increased their production of cytokines and chemokines. In addition, Nod1 and Nod2 mRNA expression was upregulated following treatment of trophoblast cells with lipopolysaccharide (LPS), and this was significantly reduced by the presence of a NFkappaB inhibitor and a TLR4-dominant negative (DN). CONCLUSION: This study demonstrates that LPS, through TLR4, increases trophoblast expression of Nod1 and Nod2 via the NFkappaB pathway; and that Nod1 is functional in the trophoblast. These findings suggest that extracellular recognition of bacterial LPS by TLR4 may prime the trophoblast in preparation for its cytoplasmic recognition of, and response to, bacterial peptides through the Nod proteins.

Activation of TLR3 in the trophoblast is associated with preterm delivery.

PROBLEM: Toll-like receptors (TLRs) recognize conserved sequences on the surface of pathogens and trigger effector cell functions. Previously, we described the expression of TLR3 by human trophoblast and their ability to respond to (Poly[I:C]). Here we evaluate the effect of Poly[I:C] on mouse pregnancy and characterize the local and systemic response. METHOD OF STUDY: C57B/6 wild type (wt) and TLR3 knockout (TLR3KO) mice were treated with Poly[I:C] at 16.5 dpc and pregnancy outcome recorded. Morphologic changes, cytokines and chemokines levels in blood and utero-placental tissue were determined. NF-kappaB pathway was evaluated in vivo and in vitro. RESULTS: Poly[I:C] in C57B/6 wt mice caused preterm delivery within 24 hr (4.5 mg/kg). No effect was observed in TLR3KO mice. In addition, we observed local (placenta) and systemic (serum) response characterized by increased production of proinflammatory cytokines and chemokines. The NF-kappaB pathway was activated by Poly[I:C] in human and mice trophoblast cells. CONCLUSION: We report that Poly[I:C] induces preterm delivery via TLR3-dependent manner. Furthermore, we demonstrate that the trophoblast is able to recognize Poly[I:C] through TLR3 and respond to viral infection, modulating the immune system at the feto-maternal interface.

Valoración del desarrollo psicomotor de lactantes prematuros de muy bajo peso de nacimiento / Evaluation of psychomotor development of premature babies with low weight at birth

La condición de prematuridad en el recién nacido es un obstáculo en la conservación del objetivo de que todos los lactantes no solamente nazcan vivos y sobrevivan, sino que, tampoco sufran tanto de trastornos físicos como psicológicos debido a un ambiente hostil en los periódos pre, intra y post parto. Desde tiempos antiguos, ha surgido un justo interés a partir de la predicción de que a medida que el índice de superiodad de lactantes de muy bajo peso de nacimiento mejora, existiría un drástico aumento del número de niños con secuelas en uno u otro sentido. La sobrevida cada vez mayor crea la necesidad de establecer un seguimiento adecuado de los recién nacidos de muy bajo peso con el objeto de evaluar las acciones del equipo de salud aplicadas durante el periodo neonatal. En el área Sur-Oriente de Santiago se creó hace más de 20 años un policlínico de recién nacido de muy bajo peso de nacimiento (menor o igual a 1500 gramos) con el objeto de proveer una atención especializada a este grupo de alto riesgo. Al mismo tiempo se pretende conocer las características de este grupo poblacional en relación con su sobrevida, evolución nutricional, desarrollo psicomotor y secuelas específicas derivadas de su prematurez. El propósito del siguiente estudio es dar a conocer las áreas del desarrollo psicomotor que se detectan a través de la Escala de Evaluación del Desarrollo Psicomotor y que resultan en riesgo o retraso en los lactantes prematuros de muy bajo peso de nacimiento. Este estudio se llevó a cabo en el Policlínico de Seguimiento del Hospital Dr. Sótero de Rio, a 88 niños a quienes se les aplicó la escala de evaluación del desarrollo psicomotor durante el curso del año 1996. El estudio es de tipo retrospectivo, descriptivo y transversal, que consistió en la revisión y análisis de los datos extraídos de las fichas clínicas y pautas de evaluación del desarrollo psicomotor. Los resultados obtenidos a través del estudio muestran que este grupo de niños refleja alteraciones específicas en el desarrollo psicomotor relacionadas no tan sólo con su condición de prematuridad, más bien, guardan estrecha relación con el medio ambiente, elemento que forma una de las bases más importantes en el desarrollo integral del niño