Parent-provider communication dynamics during the pediatric oncology diagnostic process in Guatemala: A qualitative study.

BACKGROUND: Effective communication is founded on bidirectional participation from families and healthcare providers. In adult medicine, bidirectional communication promotes treatment adherence and builds the family-provider relationship. However, the relationship between communication styles in pediatrics remains poorly understood, particularly in culturally diverse settings. This study aims to investigate parent-provider communication dynamics and parental involvement during diagnostic cancer communication in Guatemala. PROCEDURE: This qualitative study included 20 families of children with cancer and 10 providers at Unidad Nacional de Oncología Pediátrica in Guatemala. Psychoeducation and diagnostic conversations between parents, psychologists, and oncologists were recorded and thematically analyzed using a priori and novel codes exploring communication behaviors, parental engagement, and interpersonal dynamics. RESULTS: Participating parents had children with various diagnoses. Only 15% of fathers and 5% of mothers reported education beyond primary school. Providers spoke 68% of words during psychoeducation and 85% of words during diagnosis conversations. Providers used supportive communication behaviors providing explanations, demonstrating verbal attentiveness, and soliciting questions and non-supportive behaviors including paternalistic talk. Parental participation was considered active when they asked questions, expressed hopes or concerns, or asserted their opinions, and non-active when participation was limited to brief responses to closed-ended questions. Supportive provider communication often encouraged active participation; non-supportive communication did not. Furthermore, active parental participation prompted supportive communication from providers, while non-active participation did not. CONCLUSIONS: Our findings highlight the bidirectional nature of effective communication, establishing that provider communication styles both influence and are influenced by parental participation, and emphasizing the importance of supportive provider communication for patient-centered care.

Stigma in Pediatric Cancer: An Exploratory Study of Osteosarcoma and Retinoblastoma in Guatemala, Jordan, and Zimbabwe.

PURPOSE: Stigma is an understudied barrier to health care acceptance in pediatric oncology. We sought to explore the stigma experience, including its impact on cancer treatment decision making, and identify strategies to mitigate stigma for patients with osteosarcoma and retinoblastoma in Guatemala, Jordan, and Zimbabwe. METHODS: Participants included caregivers, adolescent patients (age 12-19 years), and health care clinicians. A semistructured interview guide based on The Health Stigma and Discrimination Framework (HSDF) was adapted for use at each site. Interviews were conducted in English, Spanish, Arabic, or Shona, audio-recorded, translated, and transcribed. Thematic analysis focused on stigma practices, experiences, outcomes, drivers, mitigators, and interventions. RESULTS: We conducted 56 interviews (28 caregivers, 19 health care clinicians, nine patients; 20 in Guatemala, 21 in Jordan, 15 in Zimbabwe). Major themes were organized into categories used to adapt the HSDF to global pediatric cancer care. Themes were described similarly across all sites, ages, and diagnoses, with specific cultural nuances noted. Pediatric cancer stigma was depicted as an isolating and emotional experience beginning at diagnosis and including internalized and associative stigma. Stigma affected decision making and contributed to negative outcomes including delayed diagnosis, treatment abandonment, regret, and psychosocial fragility. Overcoming stigma led to positive outcomes including resilience, treatment adherence, pride, and advocacy. Identified stigma drivers and mitigators were linked to potential interventions. CONCLUSION: Participants describe a shared stigma experience that transcends geography, cultural context, age, and diagnosis. Stigma manifestations have the potential to impact medical decision making and affect long-term psychological outcomes. Stigma assessment tools and interventions aimed at stigma mitigation including educational initiatives and support groups specific to pediatric cancer should be the focus of future research.

Understanding hope at diagnosis: A study among Guatemalan parents of children with cancer.

BACKGROUND: In high-income countries, hope facilitates parental coping and builds the clinical relationship between families of children with cancer and their clinicians. However, the manifestation of hope in low- and middle-income countries (LMICs) remains poorly understood. Our study explores Guatemalan parents' experiences with hope during the pediatric oncology diagnostic process and aims to identify discrete actions clinicians take to support hope. METHODS: This qualitative study utilized audio-recordings of the diagnostic process and an additional semi-structured interview for 20 families of children with cancer at Unidad Nacional de Oncología Pediátrica in Guatemala. Spanish audio-recordings were translated into English, transcribed, and coded using a priori and novel codes. Thematic content analysis using constant comparative methods explored parents' hopes and concerns. RESULTS: At diagnosis, Guatemalan parents expressed both hopes and concerns related to the entire cancer continuum. Throughout the diagnostic process, hope grew as concerns were alleviated. Clinicians supported hope by creating a supportive environment, providing information, affirming religious beliefs, and empowering parents. These strategies helped parents shift their focus from fear and uncertainty toward hope for their child's future. Parents expressed that establishing hope improved mood, promoted acceptance, and enabled them to care for themselves and their children. CONCLUSION: These results confirm the relevance of supporting hope in pediatric oncology settings in LMICs and suggest that culture informs hope-related needs. Supporting hope is critical across cultures and can be integrated into clinical conversation using the four processes identified by our results.

Cancer treatment decision-making among parents of paediatric oncology patients in Guatemala: a mixed-methods study.

OBJECTIVES: To examine treatment decision-making priorities and experiences among parents of children with cancer in Guatemala. SETTING: This study was conducted at Guatemala's National Pediatric Cancer Center in Guatemala City. PARTICIPANTS: Spanish-speaking parents of paediatric patients (≤18 years of age) diagnosed with any form of cancer within the 8 weeks prior to study enrolment. The quantitative portion of this study included 100 parent participants; the qualitative component included 20 parents. Most participants were Catholic or Evangelical Spanish-speaking mothers. OUTCOMES: Priorities and experiences of cancer treatment decision-making including decision-making role and experienced regret. RESULTS: A range of paediatric ages and cancer diagnoses were included. Most Guatemalan parents surveyed (70%) made decisions about their child's cancer together and almost all (94%) without input from their community. Surveyed parents predominately preferred shared decision-making with their child's oncologist (76%), however 69% agreed it was best not to be provided with many options. Two-thirds of surveyed parents (65%) held their preferred role in decision-making, with fathers more likely to hold their preferred role than mothers (p=0.02). A small number of parents (11%) experienced heightened decisional regret, which did not correlate with socio-demographic characteristics or preferred decision-making role. Qualitative results supported quantitative findings, demonstrating a decision-making process that emphasised trust and honesty. CONCLUSIONS: Guatemalan parents preferred to make decisions with their medical team and appreciated providers who were honest and inclusive, but directive about decisions. This study reinforces the importance of the provider-parent relationship and encourages clinicians in all settings to ask about and honour each parent's desired role in decision-making.

The evolution of parents' beliefs about childhood cancer during diagnostic communication: a qualitative study in Guatemala.

INTRODUCTION: Fatalistic cancer beliefs may contribute to delayed diagnosis and poor outcomes, including treatment abandonment, for children with cancer. This study explored Guatemalan parents' cancer beliefs during initial paediatric cancer communication, and the sociocultural and contextual factors that influence these beliefs. METHODS: Twenty families of children with cancer were included in this study. We audio-recorded psychosocial conversations with psychologists and diagnostic conversations with oncologists, then conducted semi-structured interviews with parents to explore the evolution of their cancer beliefs. Audio-recordings were transcribed and translated from Spanish into English, with additional review in both languages by bilingual team members. All 60 transcripts were thematically analysed using a priori and novel codes. RESULTS: Guatemalan parents' beliefs evolve as they learn about cancer through various sources. Sources of information external to the cancer centre, including prior experiences with cancer, media exposure, community discussion and clinical encounters, contribute to pre-existing beliefs. Many parents' pre-existing cancer beliefs are fatalistic; some are influenced by Mayan spirituality. Sources internal to the cancer centre include psychologists and oncologists, other providers, other patients and families. Psychologists acknowledge pre-existing beliefs and deliver cancer education using verbal explanations and hand-drawings. Oncologists provide diagnostic information and outline treatment plans. Both support hope by providing a path toward cure. Parents' lived experience is a culmination of sources and simultaneously independent. Ultimately most parents arrive at an understanding of cancer that is consistent with an allopathic medical model and offers optimism about outcomes. CONCLUSION: An interdisciplinary communication process that includes cancer education, is attentive to pre-existing beliefs, and supports hope may encourage acceptance of the allopathic medical model and need for treatment. Providers in settings of all resource levels may be able to use these techniques to support cross-cultural cancer communication, reduce treatment abandonment and improve therapy adherence.

Synthesis, physicochemical characterisation and biological activity of anandamide/ɛ-polycaprolactone nanoparticles obtained by electrospraying.

Drug encapsulation in nanocarriers such as polymeric nanoparticles (Nps) may help to overcome the limitations associated with cannabinoids. In this study, the authors' work aimed to highlight the use of electrospraying techniques for the development of carrier Nps of anandamide (AEA), an endocannabinoid with attractive pharmacological effects but underestimated due to its unfavourable physicochemical and pharmacokinetic properties added to its undesirable effects at the level of the central nervous system. The authors characterised physicochemically and evaluated in vitro biological activity of anandamide/ɛ-polycaprolactone nanoparticles (Nps-AEA/PCL) obtained by electrospraying in epithelial cells of the human proximal tubule (HK2), to prove the utility of this method and to validate the biological effect of Nps-AEA/PCL. They obtained particles from 100 to 900 nm of diameter with a predominance of 200-400 nm. Their zeta potential was -20 ± 1.86 mV. They demonstrated the stable encapsulation of AEA in Nps-AEA/PCL, as well as its dose-dependent capacity to induce the expression of iNOS and NO levels and to decrease the Na+/K+ ATPase activity in HK2 cells. Obtaining Nps-AEA/PCL by electrospraying would represent a promising methodology for a novel AEA pharmaceutical formulation development with optimal physicochemical properties, physical stability and biological activity on HK2 cells.

Current Drug Nano-targeting Strategies for Improvement in the Diagnosis and Treatment of Prevalent Pathologies such as Cardiovascular and Renal Diseases.

BACKGROUND: The kidney and cardiovascular system are closely related to each other during the modulation of the cardiovascular homeostasis. However, the search for new alternatives for the treatment and diagnosis of cardiovascular diseases does not take into account this relationship, so their evaluation results and the advantages offered by their global and integrative analysis are wasted. For example, a variety of receptors that are overexpressed in both pathologies is large enough to allow expansion in the search for new molecular targets and ligands. Nanotechnology offers pharmacological targeting strategies to kidney, heart, and blood vessels for overcoming one of the essential restrictions of traditional cardiovascular therapies the ones related to their unspecific pharmacodynamics distribution in these critical organs. RECENT FINDINGS: Drug or contrast agent nano-targeting for treatment or diagnosis of atherosclerosis, thrombosis, renal cancer or fibrosis, glomerulonephritis, among other renal, cardiac and blood vessels pathologies would allow an increase in their efficacy and a reduction of their side effects. Such effects are possible because, through pharmacological targeting, the drug is mainly found at the desired site. Review Purpose: In this mini-review, active, passive, and physical targeting strategies of several nanocarriers that have been assessed and proposed for the treatment and diagnosis of different cardiovascular diseases, are being addressed.

Improvement in treatment abandonment in pediatric patients with cancer in Guatemala.

BACKGROUND: Treatment refusal and abandonment are major causes of treatment failure for children with cancer in low- and middle-income countries (LMICs), like Guatemala. This study identified risk factors for and described the intervention that decreased abandonment. METHODS: This was a retrospective study of Guatemalan children (0-18 years) with cancer treated at the Unidad Nacional de Oncología Pediátrica (UNOP), 2001-2008, using the Pediatric Oncology Network Database. Treatment refusal was a failure to begin treatment and treatment abandonment was a lapse of 4 weeks or longer in treatment. The impact of medicina integral, a multidisciplinary psychosocial intervention team at UNOP was evaluated. Cox proportional hazards analysis identified the effect of demographic and clinical factors on abandonment. Kaplan-Meier analysis estimated the survival. RESULTS: Of 1,789 patients, 21% refused or abandoned treatment. Abandonment decreased from 27% in 2001 to 7% in 2008 following the implementation of medicina integral. Factors associated with increased risk of refusal and abandonment: greater distance to the centre (P < 0.001), younger age (P = 0.017) and earlier year of diagnosis (P < 0.001). Indigenous race/ethnicity (P = 0.002) was associated with increased risk of abandonment alone. Abandonment correlated with decreased overall survival: 0.57 ± 0.02 (survival ± standard error) for those who completed therapy versus 0.06 ± 0.02 for those who abandoned treatment (P < 0.001) at 8.3 years. CONCLUSION: This study identified distance, age, year of diagnosis and indigenous race/ethnicity as risk factors for abandonment. A multidisciplinary intervention reduced abandonment and can be replicated in other LMICs.

Retinoid X receptors orchestrate osteoclast differentiation and postnatal bone remodeling.

Osteoclasts are bone-resorbing cells that are important for maintenance of bone remodeling and mineral homeostasis. Regulation of osteoclast differentiation and activity is important for the pathogenesis and treatment of diseases associated with bone loss. Here, we demonstrate that retinoid X receptors (RXRs) are key elements of the transcriptional program of differentiating osteoclasts. Loss of RXR function in hematopoietic cells resulted in formation of giant, nonresorbing osteoclasts and increased bone mass in male mice and protected female mice from bone loss following ovariectomy, which induces osteoporosis in WT females. The increase in bone mass associated with RXR deficiency was due to lack of expression of the RXR-dependent transcription factor v-maf musculoaponeurotic fibrosarcoma oncogene family, protein B (MAFB) in osteoclast progenitors. Evaluation of osteoclast progenitor cells revealed that RXR homodimers directly target and bind to the Mafb promoter, and this interaction is required for proper osteoclast proliferation, differentiation, and activity. Pharmacological activation of RXRs inhibited osteoclast differentiation due to the formation of RXR/liver X receptor (LXR) heterodimers, which induced expression of sterol regulatory element binding protein-1c (SREBP-1c), resulting in indirect MAFB upregulation. Our study reveals that RXR signaling mediates bone homeostasis and suggests that RXRs have potential as targets for the treatment of bone pathologies such as osteoporosis.

An interactive way of learning about cancer and healthy living in a multicultural setting (part one)?

Health education is essential not only for preventing illnesses but also for knowing how to act when disease comes. In countries where the education system is inefficient for most of the population and where health issues are often ignored or mistreated because of ignorance or well-intended but ineffective belief in nature's energy and magic, it is important that people have access to truthful information about health issues. Such access allows them to act adequate knowledge and also to learn ways to avoid illness by changing their daily habits into a "healthy way of living." Approaching the young population is a way to achieve this objective. The program described here considers the education of both majority (indigenous) and minority (non indigenous) populations. It approaches the communication of information in such a way that it involves the participants in the "making" of the education. The participants actively interact with didactic material that allows them to experience "hands on" the issues about cancer and healthy living. It is intended to have a profound impact on the participant, so that he/she will remember the "education" not only as information but also as an experience. The program includes specific material for the indigenous population, which is based on their idiosyncrasy (corn plants) so that they can more easily understand the concepts. In Guatemala, UNOP (Unidad Nacional de Oncologia Pediatrica) is the only institution that provides a quality integral service for the majority of the entire children-with-cancer population. UNOP and the Psychology Department are interested in the development and implementation of education programs such as this where the participant not only learns but also experiences information about this disease and its prevention.

Effects of maternal captopril treatment during late pregnancy on neonatal lung development in rats.

The renin-angiotensin system (RAS) has been implicated in pulmonary hypertension and pulmonary fibrosis. In the present study, we examined the effects of maternal exposure to captopril (2.85 mg/kg/day) during late pregnancy (G13-G21) on postnatal rat lung development. Treatment with captopril during late pregnancy caused a significant decrease in ACE activity in P0 rats. Body weight decreased at P0 (p<0.001), P8 and P15 (p<0.01) in captopril-treated rats. Lung weight of P0 and P8 pups was lower in treated-animals (p<0.05). Lungs from captopril-treated animals showed impaired alveolar formation, with enlarged distal airway spaces at P8, P15 and P30. Interalveolar wall distance measured by mean linear intercept increased in treated vs. age-matched animals at P8, P15 (p<0.001) and P30 (p<0.05) resembling new bronchopulmonary dysplasia. In control animals, the proliferating cell nuclear antigen (PCNA) marker was higher at P0 and then drops gradually, while in captopril-treated animals PCNA marker remains higher at all stages studied. α-Smooth muscle actin (α-SMA), a marker of fibroblast differentiation into myofibroblasts, was higher at the tips of developing secondary septa in captopril-treated lungs at P8 and P15. The increased expression of PCNA and α-SMA in treated pups suggest that beyond the effect caused by captopril, the developing lungs have the capacity to recover once the treatment was stopped. Taking together the low weight, histomorphological changes and increased expression of cellular markers caused by ACE inhibition during late pregnancy, it appears that the RAS could be an intrinsic factor involved in secondary septa formation during lung development.

Bone marrow p16INK4a-deficiency does not modulate obesity, glucose homeostasis or atherosclerosis development.

OBJECTIVE: A genomic region near the CDKN2A locus, encoding p16(INK4a), has been associated to type 2 diabetes and atherosclerotic vascular disease, conditions in which inflammation plays an important role. Recently, we found that deficiency of p16(INK4a) results in decreased inflammatory signaling in murine macrophages and that p16(INK4a) influences the phenotype of human adipose tissue macrophages. Therefore, we investigated the influence of immune cell p16(INK4a) on glucose tolerance and atherosclerosis in mice. METHODS AND RESULTS: Bone marrow p16(INK4a)-deficiency in C57Bl6 mice did not influence high fat diet-induced obesity nor plasma glucose and lipid levels. Glucose tolerance tests showed no alterations in high fat diet-induced glucose intolerance. While bone marrow p16(INK4a)-deficiency did not affect the gene expression profile of adipose tissue, hepatic expression of the alternative markers Chi3l3, Mgl2 and IL10 was increased and the induction of pro-inflammatory Nos2 was restrained on the high fat diet. Bone marrow p16(INK4a)-deficiency in low density lipoprotein receptor-deficient mice did not affect western diet-induced atherosclerotic plaque size or morphology. In line, plasma lipid levels remained unaffected and p16(INK4a)-deficient macrophages displayed equal cholesterol uptake and efflux compared to wild type macrophages. CONCLUSION: Bone marrow p16(INK4a)-deficiency does not affect plasma lipids, obesity, glucose tolerance or atherosclerosis in mice.

Causas de sorderas profundas en niños chilenos asistentes a escuelas especiales para sordos / Causes of severe deafness in Chilean children enrolled in special schools for the deaf

La relación entre la audición y el desarrollo del lenguaje ha sido ampliamente demostrada, se aprende a hablar imitando los sonidos oídos y dándole la interpretación que oralmente los padres enseñan. Por ello, todos los países se están esforzando por realizar un tamizado universal en neonatos. El Estado de Chile, en un primer esfuerzo por detectar tempranamente las sorderas, está aplicando un tamizado auditivo a neonatos de alto riesgo. No hay en Chile estudio sobre las causas de sorderas, por lo cual se decidió investigar sobre esta materia en un grupo de niños sordos que estudia en alguna de las 4 escuelas especiales de Santiago. Conociendo las causas de sorderas congénitas y las de instalación en la infancia temprana, posibilita su prevención en el control del embarazo y de niño sano. Objetivo: Establecer las causas de sorderas profundas, según los conocimientos de sus padres o tutor legal y ficha escolar, en niños y jóvenes estudiantes de escuelas especiales para sordos. Material y método: En este estudio observacional, el universo fueron todos los niños que asisten a 4 escuelas especiales para sordos en Santiago. La muestra estuvo constituida por 315 casos que representan al 92 por ciento del universo. Se revisaron las fichas escolares de estos niños y la información se contrastó y completó con una entrevista a los padres o tutores. Conclusiones: El 63 por ciento de los niños presentaba sordera congénita, entre ellos el 9 por ciento fue por infección materna. Del total de la población, el 41.5 por ciento presentó sordera congénita de causa desconocida; el 13 por ciento fue adquirida por meningitis y en el 5.8 por ciento de los casos por prematurez.

The relationship between hearing and language development has been widely demonstrated, as children learn to speak by imitating sounds and interpreting them as they are orally taught by their parents. Because of this, countries are trying to put more emphasis on universal screening of newborns. In Chile, the first efforts of early detection of deafness have been in screening high risk newborns. En Chile there are no studies on the causes of deafness, and for this reason the present study seeks to investigate this issue in a group of Deaf children in special schools in Santiago. Understanding the causes of congenital and early childhood deafness allows for better prevention during pregnancy and early childhood. Objective: Establish the causes of severe deafness, according to the knowledge of parents or legal guardians and school records, in young students in special schools for the Deaf. Materials and Methods: In this observational study, the universe consisted of all children that attend 4 special schools for the Deaf in Santiago. The sample consisted of 315 cases, which represent 92 percent of the universe. School records were examined and information was contrasted and completed with and interview with parents or guardians. Conclusions: 63 percent of children suffered from congenital deafness, 9 percent of those due to infection during pregnancy. In 41.5 percent of all cases the cause of deafness was unknown. 13 percent was due to meningitis, and 5.8 percent was due to prematurity.

p16INK4a deficiency promotes IL-4-induced polarization and inhibits proinflammatory signaling in macrophages.

The CDKN2A locus, which contains the tumor suppressor gene p16(INK4a), is associated with an increased risk of age-related inflammatory diseases, such as cardiovascular disease and type 2 diabetes, in which macrophages play a crucial role. Monocytes can polarize toward classically (CAMϕ) or alternatively (AAMϕ) activated macrophages. However, the molecular mechanisms underlying the acquisition of these phenotypes are not well defined. Here, we show that p16(INK4a) deficiency (p16(-/-)) modulates the macrophage phenotype. Transcriptome analysis revealed that p16(-/-) BM-derived macrophages (BMDMs) exhibit a phenotype resembling IL-4-induced macrophage polarization. In line with this observation, p16(-/-) BMDMs displayed a decreased response to classically polarizing IFNγ and LPS and an increased sensitivity to alternative polarization by IL-4. Furthermore, mice transplanted with p16(-/-) BM displayed higher hepatic AAMϕ marker expression levels on Schistosoma mansoni infection, an in vivo model of AAMϕ phenotype skewing. Surprisingly, p16(-/-) BMDMs did not display increased IL-4-induced STAT6 signaling, but decreased IFNγ-induced STAT1 and lipopolysaccharide (LPS)-induced IKKα,ß phosphorylation. This decrease correlated with decreased JAK2 phosphorylation and with higher levels of inhibitory acetylation of STAT1 and IKKα,ß. These findings identify p16(INK4a) as a modulator of macrophage activation and polarization via the JAK2-STAT1 pathway with possible roles in inflammatory diseases.

Differential lipid partitioning between adipocytes and tissue macrophages modulates macrophage lipotoxicity and M2/M1 polarization in obese mice.

OBJECTIVE: Obesity-associated insulin resistance is characterized by a state of chronic, low-grade inflammation that is associated with the accumulation of M1 proinflammatory macrophages in adipose tissue. Although different evidence explains the mechanisms linking the expansion of adipose tissue and adipose tissue macrophage (ATM) polarization, in the current study we investigated the concept of lipid-induced toxicity as the pathogenic link that could explain the trigger of this response. RESEARCH DESIGN AND METHODS: We addressed this question using isolated ATMs and adipocytes from genetic and diet-induced murine models of obesity. Through transcriptomic and lipidomic analysis, we created a model integrating transcript and lipid species networks simultaneously occurring in adipocytes and ATMs and their reversibility by thiazolidinedione treatment. RESULTS: We show that polarization of ATMs is associated with lipid accumulation and the consequent formation of foam cell-like cells in adipose tissue. Our study reveals that early stages of adipose tissue expansion are characterized by M2-polarized ATMs and that progressive lipid accumulation within ATMs heralds the M1 polarization, a macrophage phenotype associated with severe obesity and insulin resistance. Furthermore, rosiglitazone treatment, which promotes redistribution of lipids toward adipocytes and extends the M2 ATM polarization state, prevents the lipid alterations associated with M1 ATM polarization. CONCLUSIONS: Our data indicate that the M1 ATM polarization in obesity might be a macrophage-specific manifestation of a more general lipotoxic pathogenic mechanism. This indicates that strategies to optimize fat deposition and repartitioning toward adipocytes might improve insulin sensitivity by preventing ATM lipotoxicity and M1 polarization.

Inflammatory mediators and insulin resistance in obesity: role of nuclear receptor signaling in macrophages.

Visceral obesity is coupled to a general low-grade chronic inflammatory state characterized by macrophage activation and inflammatory cytokine production, leading to insulin resistance (IR). The balance between proinflammatory M1 and antiinflammatory M2 macrophage phenotypes within visceral adipose tissue appears to be crucially involved in the development of obesity-associated IR and consequent metabolic abnormalities. The ligand-dependent transcription factors peroxisome proliferator activated receptors (PPARs) have recently been implicated in the determination of the M1/M2 phenotype. Liver X receptors (LXRs), which form another subgroup of the nuclear receptor superfamily, are also important regulators of proinflammatory cytokine production in macrophages. Disregulation of macrophage-mediated inflammation by PPARs and LXRs therefore underlies the development of IR. This review summarizes the role of PPAR and LXR signaling in macrophages and current knowledge about the impact of these actions in the manifestation of IR and obesity comorbidities such as liver steatosis and diabetic osteopenia.

Inflammatory protein sPLA(2)-IIA abrogates TNFalpha-induced apoptosis in human astroglioma cells: Crucial role of ERK.

Brain injury induces the expression of well-known cytokines, such as tumor necrosis factor-alpha (TNFalpha), and other, which functions are less understood, as secreted phospholipase A(2) group IIA (sPLA(2)-IIA). Since in pathological processes, cytokines function coordinately in networks, to further explore the actions of sPLA(2)-IIA in tumorigenesis, we investigated the effect of sPLA(2)-IIA in the presence of TNFalpha in human 1321N1 astrocytoma cells. In these cells, TNFalpha activates the apoptotic programme that is accompanied of cytoskeleton changes; however, simultaneous treatment with sPLA(2)-IIA prevents TNFalpha-mediated apoptosis and reverses the modification of the markers associated to this response. In fact, the mitogenic activity elicited by the phospholipase alone is preserved. This inhibitory effect is not found in other TNFalpha-mediated responses, even a functional cooperation is observed on COX-2 protein induction. The cross-talk between TNFalpha and sPLA(2)-IIA is associated with ERK activity since its pharmacological inhibition attenuates both synergistic and inhibitory responses. We have also observed that upon sPLA(2)-IIA stimulation, endogenous ERK has the capacity to bind and phosphorylate sequences present within the cytoplasmic domain of TNFR1/CD120a. These findings thus indicate that sPLA(2)-IIA and TNFalpha transduction pathways interact to modulate inflammatory responses and provide additional insights about the capacity of sPLA(2)-IIA to promote apoptosis resistance in astrocytoma cells.

Secreted phospholipase A2-IIA modulates key regulators of proliferation on astrocytoma cells.

Human group IIA secreted phospholipase A(2) (sPLA(2)-IIA) has been characterized in numerous inflammatory and neoplastic conditions. sPLA(2)-IIA can either promote or inhibit cell growth depending on the cellular type and the specific injury. We have previously demonstrated that exogenous sPLA(2)-IIA, by engagement to a membrane structure, induces proliferation and activation of mitogen-activated protein kinases cascade in human astrocytoma cells. In this study, we used human astrocytoma 1321N1 cells to investigate the key molecules mediating sPLA(2)-IIA-induced cell proliferation. We found that sPLA(2)-IIA promoted reactive oxygen species (ROS) accumulation, which was abrogated in the presence of allopurinol and DPI, but not by rotenone, discarding mitochondria as a ROS source. In addition, sPLA(2)-IIA triggered Ras and Raf-1 activation, with kinetics that paralleled ERK phosphorylation, and co-immunoprecipitation assays indicated an association between Ras, Raf-1 and ERK. Additionally, Akt, p70 ribosomal protein S6 kinase, and S6 ribosomal protein were also phosphorylated upon sPLA(2)-IIA treatment, effect that was abrogated by N-acetylcysteine or LY294002 treatment indicating that ROS and phosphatidylinositol 3 kinase are upstream signaling regulators. As the inhibitors N-acetylcysteine, PD98059, LY294002 or rapamycin blocked sPLA(2)-IIA-induced proliferation without activation of the apoptotic program, we suggest that inhibition of these intracellular signal transduction elements may represent a mechanism of growth arrest. Our results reveal new potential targets for therapeutic intervention in neuroinflammatory disorders and brain cancer in particular.

PPARalpha agonists suppress osteopontin expression in macrophages and decrease plasma levels in patients with type 2 diabetes.

Osteopontin (OPN) is a proinflammatory cytokine implicated in the chemoattraction of monocytes and the development of atherosclerosis. Peroxisome proliferator-activated receptor (PPAR)alpha, a ligand-activated transcription factor with pleiotropic anti-inflammatory effects in macrophages, is the molecular target for fibrates, which are frequently used to treat dyslipidemia in patients with type 2 diabetes at high risk for cardiovascular disease. In the present study, we examined the regulation of OPN by PPARalpha agonists in macrophages and determined the effect of fibrate treatment on OPN plasma levels in patients with type 2 diabetes. Treatment of human macrophages with the PPARalpha ligands bezafibrate or WY14643 inhibited OPN expression. PPARalpha ligands suppressed OPN promoter activity, and an activator protein (AP)-1 consensus site conferred this repression. Overexpression of c-Fos and c-Jun reversed the inhibitory effect of PPARalpha ligands on OPN transcription, and, in chromatin immunoprecipitation assays, PPARalpha ligands inhibited c-Fos and phospho-c-Jun binding to the OPN promoter. Moreover, c-Fos and phospho-c-Jun protein expression was inhibited by PPARalpha agonists, indicating that PPARalpha ligands suppress OPN expression through negative cross talk with AP-1-dependent transactivation of the OPN promoter. This inhibitory effect of PPARalpha ligands on OPN expression was absent in PPARalpha-deficient macrophages, suggesting a receptor-mediated mechanism of OPN suppression. Finally, treatment of type 2 diabetic patients with bezafibrate significantly decreased OPN plasma levels. These results demonstrate a novel mechanism whereby PPARalpha ligands may impact macrophage inflammatory responses and decrease early proinflammatory markers for cardiovascular disease.

Bromoenol lactone promotes cell death by a mechanism involving phosphatidate phosphohydrolase-1 rather than calcium-independent phospholipase A2.

Originally described as a serine protease inhibitor, bromoenol lactone (BEL) has recently been found to potently inhibit Group VI calcium-independent phospholipase A2 (iPLA2). Thus, BEL is widely used to define biological roles of iPLA2 in cells. However, BEL is also known to inhibit another key enzyme of phospholipid metabolism, namely the magnesium-dependent phosphatidate phosphohydrolase-1 (PAP-1). In this work we report that BEL is able to promote apoptosis in a variety of cell lines, including U937, THP-1, and MonoMac (human phagocyte), RAW264.7 (murine macrophage), Jurkat (human T lymphocyte), and GH3 (human pituitary). In these cells, long term treatment with BEL (up to 24 h) results in increased annexin-V binding to the cell surface and nuclear DNA damage, as detected by staining with both DAPI and propidium iodide. At earlier times (2 h), BEL induces the proteolysis of procaspase-9 and procaspase-3 and increases cleavage of poly(ADP-ribose) polymerase. These changes are preceded by variations in the mitochondrial membrane potential. All these effects of BEL are not mimicked by the iPLA2 inhibitor methylarachidonyl fluorophosphonate or by treating the cells with a specific iPLA2 antisense oligonucleotide. However, propranolol, a PAP-1 inhibitor, is able to reproduce these effects, suggesting that it is the inhibition of PAP-1 and not of iPLA2 that is involved in BEL-induced cell death. In support of this view, BEL-induced apoptosis is accompanied by a very strong inhibition of PAP-1-regulated events, such as incorporation of [3H]choline into phospholipids and de novo incorporation of [3H]arachidonic acid into triacylglycerol. Collectively, these results stress the role of PAP-1 as a key enzyme for cell integrity and survival and in turn caution against the use of BEL in studies involving long incubation times, due to the capacity of this drug to induce apoptosis in a variety of cells.