Systematic review and meta-analysis of colon capsule endoscopy accuracy for colorectal cancer screening. An alternative during the Covid-19 pandemic?

AIM: To determine the diagnostic accuracy of colon capsule endoscopy for colorectal cancer screening. METHODS: Studies that compared the diagnostic performance of colonoscopy and second-generation colon capsule endoscopy (CCE-2) for screening of asymptomatic patients aged 50-75 years were included. The primary outcomes were sensitivity, specificity, and positive and negative likelihood ratios for polyps and adenomas measuring at least 6 mm or 10 mm. RESULTS: Eight full-text studies that evaluated 1602 patients were included for systematic review. Of these, 840 (52.43%) patients participated in an opportunistic screening program. The pooled outcomes of CCE-2 for polyps at least 6 mm / 10 mm were (CI = confidence interval): sensitivity: 88% (95% CI: 0.84-0.91) / 88% (95% CI: 0.82-0.93), specificity: 94% (95% CI: 0.92-0.95) / 95.5% (95% CI: 0.94-0.97); positive likelihood ratio: 11.86 (95% CI: 5.53-25.46) / 23.07 (95% CI: 6.163-86.36); negative likelihood ratio: 0.14 (95% CI: 0.1-0.21) / 0.14 (95% CI: 0.09-0.21). The area under the summary receiver operating characteristic curve for polyps at least 6 and 10 mm was 96.3% and 96.7%, respectively. The only cancer missed by complete CCE-2 was shown at multiple frames in the unblinded review. In total, 125 (7.8%) patients presented mild adverse events mostly related to bowel preparation. CONCLUSION: CCE-2 is demonstrated to be an effective and safe alternative method for colorectal cancer screening. Diagnostic performance of CCE-2 for polyps of at least 6 and 10 mm was similar. Completion rates still need to be improved.

Influence of lysosomal protease sensitivity in the immunogenicity of the antitumor biopharmaceutical asparaginase.

L-asparaginase (ASNase) from Escherichia coli (EcAII) is used in the treatment of acute lymphoblastic leukaemia (ALL). EcAII activity in vivo has been described to be influenced by the human lysosomal proteases asparaginyl endopeptidase (AEP) and cathepsin B (CTSB); these hydrolases cleave and could expose epitopes associated with the immune response against EcAII. In this work, we show that ASNase resistance to CTSB and/or AEP influences the formation of anti-ASNase antibodies, one of the main causes of hypersensitivity reactions in patients. Error-prone polymerase chain reaction was used to produce variants of EcAII more resistant to proteolytic cleavage by AEP and CTSB. The variants with enzymatic activity and cytotoxicity levels equivalent to or better than EcAII WT were submitted to in vivo assays. Only one of the mutants presented increased serum half-life, so resistance to these proteases is not the only feature involved in EcAII stability in vivo. Our results showed alteration of the phenotypic profile of B cells isolated after animal treatment with different protease-resistant proteoforms. Furthermore, mice that were exposed to the protease-resistant proteoforms presented lower anti-asparaginase antibodies production in vivo. Our data suggest that modulating resistance to lysosomal proteases can result in less immunogenic protein drugs.

Extracellular annexin-A1 promotes myeloid/granulocytic differentiation of hematopoietic stem/progenitor cells via the Ca2+/MAPK signalling transduction pathway.

Annexin A1 (AnxA1) modulates neutrophil life span and bone marrow/blood cell trafficking thorough activation of formyl-peptide receptors (FPRs). Here, we investigated the effect of exogenous AnxA1 on haematopoiesis in the mouse. Treatment of C57BL/6 mice with recombinant AnxA1 (rAnxA1) reduced the granulocyte-macrophage progenitor (GMP) population in the bone marrow, enhanced the number of mature granulocytes Gr-1+Mac-1+ in the bone marrow as well as peripheral granulocytic neutrophils and increased expression of mitotic cyclin B1 on hematopoietic stem cells (HSCs)/progenitor cells (Lin-Sca-1+c-Kit+: LSK). These effects were abolished by simultaneous treatment with Boc-2, an FPR pan-antagonist. In in vitro studies, rAnxA1 reduced both HSC (LSKCD90lowFLK-2-) and GMP populations while enhancing mature cells (Gr1+Mac1+). Moreover, rAnxA1 induced LSK cell proliferation (Ki67+), increasing the percentage of cells in the S/G2/M cell cycle phases and reducing Notch-1 expression. Simultaneous treatment with WRW4, a selective FPR2 antagonist, reversed the in vitro effects elicited by rAnxA1. Treatment of LSK cells with rAnxA1 led to phosphorylation of PCLγ2, PKC, RAS, MEK, and ERK1/2 with increased expression of NFAT2. In long-term bone marrow cultures, rAnxA1 did not alter the percentage of LSK cells but enhanced the Gr-1+Mac-1+ population; treatment with a PLC (U73122), but not with a PKC (GF109203), inhibitor reduced rAnxA1-induced phosphorylation of ERK1/2 and Elk1. Therefore, we identify here rAnxA1 as an inducer of HSC/progenitor cell differentiation, favouring differentiation of the myeloid/granulocytic lineage, via Ca2+/MAPK signalling transduction pathways.

DOES MALE GENDER INCREASE THE RISK OF LAPAROSCOPIC CHOLECYSTECTOMY?

BACKGROUND: Laparoscopic cholecystectomy is the preferable treatment for chronic or acute cholecystitis. Some factors may increase the rate of laparoscopic conversion to open cholecystectomy and perioperative complications. The role of gender as a risk factor for laparoscopic cholecystectomy is controversial. AIM: To evaluate the role of the gender on the operative findings and outcome of laparoscopic cholecystectomy. METHOD: All patients who underwent laparoscopic cholecystectomy for chronic or acute cholecystitis were included. Demographic, clinical, laboratory, imaging exams, intraoperative and postoperative data were obtained and analyzed. The data was obtained retrospectively from electronic medical records and study protocols. RESULTS: Of a total 1,645 patients who were subjected to laparoscopic cholecystectomy, 540 (32.8%) were men and 1,105 (67.2%) were women. Mean age was similar in both genders (p=0.817). Operative time has longer in the male (72.48±28.50) than in the female group (65.46±24.83, p<0.001). The rate of acute cholecystitis was higher in the male (14.3%) than in the female group (5.1%, p<0.001). There was no difference between the genders in regard to the rate of conversion (p=1.0), intraoperative complication (p=1.0), postoperative complication (p=0.571), and operative mortality (p=1.0). CONCLUSION: Male gender is not an independent risk factor for laparoscopic conversion and perioperative complications.

Does Intradialytic Exercise Improve Removal of Solutes by Hemodialysis? A Systematic Review and Meta-analysis.

OBJECTIVE: To describe a systematic review and meta-analysis to identify if intradialytic exercise improves the removal of solutes and the hemodialysis adequacy. DATA SOURCES: A systematic review and meta-analysis of randomized controlled trials (RCTs) were performed. The sources were MEDLINE (via PubMed), Web of Science, LILACS, and SciELO, from inception until July 2018. STUDY SELECTION: Clinical trials including patients on chronic hemodialysis submitted to the intervention of aerobic intradialytic exercise. DATA EXTRACTION: Evaluating as outcomes the removal of solutes (creatinine, phosphate, potassium) and/or adequacy parameters (Kt/V-urea). DATA SYNTHESIS: The systematic review included 23 studies (7 evaluating the effect of 1 exercise session and 16 evaluating the effect of training, lasting from 6 to 25 weeks). Eleven RCT were included in the meta-analyses. It was observed that the aerobic intradialytic exercise increased the Kt/V-urea (0.15; 95% confidence interval [95% CI], 0.08-0.21) and decreased creatinine (-1.82 mg/dL; 95% CI, -2.50 to -1.13), despite the high heterogeneity of the analysis. No differences were found in phosphorus and potassium removal. CONCLUSION: The aerobic intradialytic exercise may be suggested to improve the Kt/V-urea and the creatinine removal during the dialysis.

Endoscopic versus surgical treatment for pancreatic pseudocysts: Systematic review and meta-analysis.

OBJECTIVE: This systematic review and meta-analysis aims to compare surgical and endoscopic treatment for pancreatic pseudocyst (PP). METHODS: The researchers did a search in Medline, EMBASE, Scielo/Lilacs, and Cochrane electronic databases for studies comparing surgical and endoscopic drainage of PP s in adult patients. Then, the extracted data were used to perform a meta-analysis. The outcomes were therapeutic success, drainage-related adverse events, general adverse events, recurrence rate, cost, and time of hospitalization. RESULTS: There was no significant difference between treatment success rate (risk difference [RD] -0.09; 95% confidence interval [CI] [0.20,0.01]; P = .07), drainage-related adverse events (RD -0.02; 95% CI [-0.04,0.08]; P = .48), general adverse events (RD -0.05; 95% CI [-0.12, 0.02]; P = .13) and recurrence (RD: 0.02; 95% CI [-0.04,0.07]; P = .58) between surgical and endoscopic treatment.Regarding time of hospitalization, the endoscopic group had better results (RD: -4.23; 95% CI [-5.18, -3.29]; P < .00001). When it comes to treatment cost, the endoscopic arm also had better outcomes (RD: -4.68; 95% CI [-5.43,-3.94]; P < .00001). CONCLUSION: There is no significant difference between surgical and endoscopic treatment success rates, adverse events and recurrence for PP. However, time of hospitalization and treatment costs were lower in the endoscopic group.

SYSTEMIZATION OF LAPAROSCOPIC INGUINAL HERNIA REPAIR (TAPP) BASED ON A NEW ANATOMICAL CONCEPT: INVERTED Y AND FIVE TRIANGLES.

BACKGROUND: Laparoscopic inguinal hernia repair has been shown to be superior than open repairs with faster return to daily activities and decrease in the occurrence of chronic pain. However, higher direct costs and mandatory use of general anesthesia are arguments against their use. In addition, increased complexity of surgery resulting from an anatomy that is unusual to general surgeons prevents the widespread adoption of laparoscopic approach. AIM: To propose a technical systematization for transabdominal laparoscopic repair (TAPP) of inguinal hernias based on anatomical concepts. METHOD: To offer a systematization of TAPP repair based on well defined anatomic landmarks, describing the concept of "inverted Y", identification of five triangles and three zones of dissection, to achieve the "critical view of safety" for laparoscopic inguinal hernia repair. RESULTS: Since this standardization was developed five years ago, many surgeons were trained following these precepts. Reproducibility is high, as far as, it´s rate of adoption among surgeons. CONCLUSION: The concept of the "inverted Y", "Five triangles" and the dissection based in "Three Zones" establish an effective and reproducible standardization of the TAPP technique.

Does male gender increase the risk of laparoscopic cholecystectomy? / O gênero masculino aumenta o risco de colecistectomia laparoscópica?

ABSTRACT Background: Laparoscopic cholecystectomy is the preferable treatment for chronic or acute cholecystitis. Some factors may increase the rate of laparoscopic conversion to open cholecystectomy and perioperative complications. The role of gender as a risk factor for laparoscopic cholecystectomy is controversial. Aim: To evaluate the role of the gender on the operative findings and outcome of laparoscopic cholecystectomy. Method: All patients who underwent laparoscopic cholecystectomy for chronic or acute cholecystitis were included. Demographic, clinical, laboratory, imaging exams, intraoperative and postoperative data were obtained and analyzed. The data was obtained retrospectively from electronic medical records and study protocols. Results: Of a total 1,645 patients who were subjected to laparoscopic cholecystectomy, 540 (32.8%) were men and 1,105 (67.2%) were women. Mean age was similar in both genders (p=0.817). Operative time has longer in the male (72.48±28.50) than in the female group (65.46±24.83, p<0.001). The rate of acute cholecystitis was higher in the male (14.3%) than in the female group (5.1%, p<0.001). There was no difference between the genders in regard to the rate of conversion (p=1.0), intraoperative complication (p=1.0), postoperative complication (p=0.571), and operative mortality (p=1.0). Conclusion: Male gender is not an independent risk factor for laparoscopic conversion and perioperative complications.

RESUMO Racional: A colecistectomia laparoscópica é o tratamento de escolha para colecistite crônica ou aguda. Alguns fatores podem aumentar a taxa de conversão para colecistectomia laparotômica e de complicações perioperatórias. O papel do gênero, como um fator de risco para colecistectomia laparoscópica, é controverso. Objetivo: Avaliar o papel do gênero nos achados operatórios e no desfecho da colecistectomia laparoscópica. Métodos: Todos os pacientes que foram submetidos à colecistectomia laparoscópica por colecistite crônica ou aguda foram incluídos. Dados demográficos, clínicos, laboratoriais, de imagem, intraoperatórios e pós-operatórios foram obtidos e analisados. Os dados foram obtidos retrospectivamente a partir de prontuários eletrônicos e protocolos de estudo. Resultados: De um total de 1.645 pacientes que foram submetidos à colecistectomia laparoscópica, 540 (32,8%) eram homens e 1.105 (67,2%) mulheres. A idade média foi semelhante em ambos os gêneros (p=0,817). O tempo operatório foi maior nos homens (72,48±28,50) do que nas mulheres (65,46±24,83) (p<0,001). A taxa de colecistite aguda foi maior no grupo masculino (14,3%) do que no feminino (5,1%, p<0,001). Não houve diferença entre os gêneros quanto à taxa de conversão (p=1,0), complicação intraoperatória (p=1,0), complicação pós-operatória (p=0,571) e mortalidade operatória (p=1,0). Conclusão: O gênero masculino não é fator de risco independente para a conversão laparoscópica e complicações perioperatórias.

Systemization of laparoscopic inguinal hernia repair (tapp) based on a new anatomical concept: inverted y and five triangles / Sistematização do reparo da hérnia inguinal laparoscópica (tapp) baseada em um novo conceito anatômico: y invertido e cinco triângulos

ABSTRACT Background: Laparoscopic inguinal hernia repair has been shown to be superior than open repairs with faster return to daily activities and decrease in the occurrence of chronic pain. However, higher direct costs and mandatory use of general anesthesia are arguments against their use. In addition, increased complexity of surgery resulting from an anatomy that is unusual to general surgeons prevents the widespread adoption of laparoscopic approach. Aim: To propose a technical systematization for transabdominal laparoscopic repair (TAPP) of inguinal hernias based on anatomical concepts. Method: To offer a systematization of TAPP repair based on well defined anatomic landmarks, describing the concept of "inverted Y", identification of five triangles and three zones of dissection, to achieve the "critical view of safety" for laparoscopic inguinal hernia repair. Results: Since this standardization was developed five years ago, many surgeons were trained following these precepts. Reproducibility is high, as far as, it´s rate of adoption among surgeons. Conclusion: The concept of the "inverted Y", "Five triangles" and the dissection based in "Three Zones" establish an effective and reproducible standardization of the TAPP technique.

RESUMO Racional: O reparo laparoscópico da hérnia inguinal tem se mostrado superior aos reparos abertos, com retorno mais rápido às atividades diárias e diminuição na ocorrência de dor crônica. No entanto, custos diretos mais altos e o uso obrigatório de anestesia geral são argumentos contra seu uso. Além disso, o aumento da complexidade da operação resultante de uma anatomia incomum aos cirurgiões gerais impede a ampla adoção da abordagem laparoscópica. Objetivo: Propor uma sistematização técnica para reparo laparoscópico transabdominal (TAPP) de hérnias inguinais com base em conceitos anatômicos. Método: Oferecer sistematização do reparo do TAPP baseado em pontos anatômicos bem definidos, descrevendo o conceito de "Y invertido", identificação de cinco triângulos e três zonas de dissecação, para alcançar a "visão crítica de segurança" para o reparo de hérnia inguinal laparoscópica. Resultados: Desde que essa padronização foi desenvolvida há cinco anos, muitos cirurgiões foram treinados seguindo esses preceitos. A reprodutibilidade é muito alta, assim como a taxa de adoção entre cirurgiões. Conclusão: O conceito de "Y invertido", dos "Cinco triângulos" e a dissecção baseada em "Três Zonas" estabelecem uma padronização efetiva e reprodutível da técnica TAPP.

Computed tomography colonography versus colonoscopy for the diagnosis of colorectal cancer: a systematic review and meta-analysis.

Colorectal cancer (CRC) is a significant cause of morbidity and mortality. Optical colonoscopy (OC) is the first choice of investigation for assessing the state of the colon and it is excellent for CRC screening. Newer technologies such as computed tomography colonography (CTC) may also be useful in CRC screening. This systematic review compares the benefits of CTC and OC for CRC screening. This review includes all the available randomized clinical trials comparing CTC and OC for CRC screening in asymptomatic patients. Three studies were included in the systematic review and were submitted for meta-analysis. In the analysis of participation rates, only 2,333 of 8,104 (29%) patients who were invited for screening underwent the CTC, and only 1,486 of the 7,310 (20%) patients who were invited for screening underwent OC. The absolute risk difference in participation rate in the two procedures was 0.1 (95% CI, 0.05-0.14) in favor of CTC. In the analysis of advanced colorectal neoplasia (ACN) detection rates, 2,357 patients undergoing CTC and 1,524 patients undergoing OC were included. Of these, 135 patients (5.7%) who underwent a CTC and 130 patients (8.5%) who underwent an OC were diagnosed with ACN. The absolute risk difference in ACN detection rate in the two procedure types was -0.02 (with a 95% CI between -0.04 and -0.00) in favor of OC. CTC is an option for CRC screening in asymptomatic patients. However, as CTC was inferior in detecting ACN, it should not replace OC, which remains the gold standard.

Surgical Management of Solid Pseudopapillary Tumor of the Pancreas.

BACKGROUND AND OBJECTIVES: Although solid pseudopapillary tumor (SPT) of the pancreas is rare, its diagnosis has increased severalfold in the past decades. We present our experience in the management of SPT, including a patient who experienced tumor rupture during laparoscopy pancreatic resection. METHODS: Data on all patients with SPT who were subjected to surgical treatment were retrospectively obtained. RESULTS: Of 20 patients evaluated, 17 (85%) were females. The mean age was 31 years. Tumor size varied from 2.7 × 1.5 to 13.5 × 10.0 cm, with a mean of 6.4 × 7.6 cm. The most common location was the tail and/or body of the pancreas (14 patients [70%]). Pancreatic tumor resection was performed in 19 patients (50%). The type of resection depended on tumor location and size: distal pancreatectomy (n = 13), pancreatoduodenectomy (n = 5), and central pancreatectomy (n = 1) Pancreatic resection was performed via laparoscopy in 7 patients who underwent distal pancreatectomy. Tumor resection was not performed in only 1 patient (5%), due to invasion of mesenteric vessels and presence of liver metastases. One patient had tumor rupture during laparoscopic resection, with no apparent macroscopic dissemination of the tumor. All 19 patients who underwent SPT resection had no tumor recurrence, including a patient with capsule invasion and another patient with tumor rupture during surgical dissection. The mean follow-up time was 38 months (range, 6-72 months). CONCLUSION: Complete SPT resection is possible in most patients, with a low recurrence rate. Because of its large size, laparoscopic resection of SPT's should be performed only by experienced surgeons to avoid tumor rupture.

Gomesin acts in the immune system and promotes myeloid differentiation and monocyte/macrophage activation in mouse.

Due to the cytotoxic effect of antimicrobial peptides (AMP) against several microorganism and tumor cells has been proposed their association with the immune system. However, just a few reports have shown this relationship. In this study, mice were treated with gomesin, a ß-hairpin AMP that exhibit high cytotoxicity against bacterial and tumor cells. Different effects in the immune system were observed, such as, decrease of CD3+ in T lymphocytes (Control: 17.7±1.4%; Gomesin: 7.67±1.2%) and in hematopoietic progenitors and increase of hematopoietic stem cell (Control: 0.046±0.004%; Gomesin: 0.067±0.003%), B220+ B lymphocytes (Control: 38.63±1.5%; Gomesin: 47.83±0.48%), and Mac-1+F4/80+ macrophages (Control: 11.76±3.4%; Gomesin: 27.13±4.0%). Additionally, macrophage increase was accompanied by an increase of macrophage phagocytosis (Control 20.85±1.53; Gomesin 31.32±1 Geometric mean), interleukin 6 (Control: 47.24±1.9ng/mL; Gomesin: 138.68±33.68ng/mL) and monocyte chemoattractant protein-1 (Control: 0.872±0.093ng/mL; Gomesin: 1.83±0.067ng/mL). Thus, this report showed immunomodulatory activity of gomesin in the immune system of mice.

Umbilical hernia in patients with liver cirrhosis: A surgical challenge.

Umbilical hernia occurs in 20% of the patients with liver cirrhosis complicated with ascites. Due to the enormous intraabdominal pressure secondary to the ascites, umbilical hernia in these patients has a tendency to enlarge rapidly and to complicate. The treatment of umbilical hernia in these patients is a surgical challenge. Ascites control is the mainstay to reduce hernia recurrence and postoperative complications, such as wound infection, evisceration, ascites drainage, and peritonitis. Intermittent paracentesis, temporary peritoneal dialysis catheter or transjugular intrahepatic portosystemic shunt may be necessary to control ascites. Hernia repair is indicated in patients in whom medical treatment is effective in controlling ascites. Patients who have a good perspective to be transplanted within 3-6 mo, herniorrhaphy should be performed during transplantation. Hernia repair with mesh is associated with lower recurrence rate, but with higher surgical site infection when compared to hernia correction with conventional fascial suture. There is no consensus on the best abdominal wall layer in which the mesh should be placed: Onlay, sublay, or underlay. Many studies have demonstrated several advantages of the laparoscopic umbilical herniorrhaphy in cirrhotic patients compared with open surgical treatment.

Palladacycle (BPC) antitumour activity against resistant and metastatic cell lines: the relationship with cytosolic calcium mobilisation and cathepsin B activity.

The search for new compounds that induce p53-independent apoptosis is the focus of many studies in cancer biology because these compounds could be more specific and would overcome chemotherapy resistance. In this study, we evaluated the in vitro antitumour activity of a Biphosphinic Palladacycle Complex (BPC) and extended preclinical studies to an in vivo model. Saos-2 cells, a p53-null human osteosarcoma drug-resistant cell line, were treated with BPC in the presence or absence of a cathepsin B inhibitor and a calcium chelator (CA074 and BAPTA-AM, respectively), and several parameters related to apoptosis were evaluated. Preclinical studies were performed with mice that were intravenously inoculated with murine melanoma B16F10-Nex2 cells and treated intraperitoneally (i.p.) with BPC (8 mg/kg/day) for ten consecutive days, when lung metastatic nodules were counted. In vitro data show that BPC induces cell death in Saos-2 cells mainly by apoptosis, which was accompanied by the effector caspase-3 activation. These events are most likely related to Bax translocation and increased cytosolic calcium mobilisation, mainly from intracellular compartments. Lysosomal Membrane Permeabilisation (LMP) was also observed after 12 h of BPC exposure. Interestingly, BAPTA-AM and CA074 significantly decreased BPC cytotoxicity, suggesting that both calcium and cathepsin B are required for BPC antitumour activity. In vivo studies demonstrated that BPC protects mice against murine metastatic melanoma. In conclusion, BPC complex is an effective anticancer compound against metastatic murine melanoma. This complex is cytotoxic to the drug-resistant osteosarcoma Saos-2 human tumour cells by inducing apoptosis triggered by calcium signalling and a lysosomal-dependent pathway.

Comparative study of autophagy inhibition by 3MA and CQ on Cytarabine­induced death of leukaemia cells.

BACKGROUND: As the molecular mechanisms of Cytarabine,one of the most important drugs used in the leukaemia's treatment, are only partially understood and the role of autophagy on leukaemia development and treatment is only recently being investigated, in this study, by using Chloroquine (CQ) and 3-methyladenine (3MA) as autophagy inhibitors, we aim to evaluate the contribution of an autophagic mechanism to Cytarabine (AraC)-induced death of HL60 leukaemia cells. METHODS: Trypan blue exclusion and AnnexinV/PI assays were used to evaluate HL60 cell death under AraC treatment in the presence or absence of 3MA and CQ. Western blotting and immunofluorescence experiments were performed to show the involvement of apoptosis and autophagy protein expressions. Phenotypic characterization of HL60-treated cells was performed by using immunophenotyping. Clonogenic assays were applied to analyse clonal function of HL60-treated cells. RESULTS: We observed that although autophagy inhibition by 3MA, but not CQ, increased the death of HL60 AraC cells after 24 h of treatment, no significant differences between AraC and AraC + 3MA-treated groups were observed by using clonogenic assay. In addition, increased number of immature (CD34(+)/CD38(−)Lin(−/low)) HL60 cells was found in AraC and AraC-3MA groups when compared with control untreated cells. CONCLUSIONS: Although AraC anti-leukaemia effects could be potentiated by 3MA autophagy inhibition after 24 h of exposure, leukaemia cell resistance, the main causes of treatment failure, is also promoted by autophagy initial stage impairment by 3MA, denoting the complex role of autophagy in leukaemia cells' response to chemotherapy.

Hematopoietic stem cell expansion caused by a synthetic fragment of leptin.

Leptin is a cytokine that regulates food intake, energy expenditure and hematopoiesis. Based on the tridimensional structure of the human leptin molecule, six fragments have been synthesized, (Ac-Lep23-47-NH2, [LEP1]; Ac-Lep48-71-NH2, [LEP2]; Ac-Lep72-88-NH2, [LEP3]; Ac-Lep92-115-NH2, [LEP4], Ac-[Ser(117)]-Lep116-140-NH2, [LEP5] and Ac-Lep141-164-NH2, [LEP6]), and their effects on hematopoiesis were evaluated. The mice were treated with 1mg/kg LEP5 for 3 days. The mature and primitive hematopoietic populations were quantified. We observed that the mature populations from the bone marrow and spleen were not affected by LEP5. However, the peptide caused at least a two-fold increase in the number of hematopoietic stem cells, the most primitive population of the bone marrow. Additionally, the number of granulocyte/macrophage colony-forming units produced by bone marrow cells in methylcellulose also increased by 40% after treatment with LEP5, and the leptin receptor was activated. These results show that the leptin fragment LEP5 is a positive modulator of the in vivo expansion of hematopoietic stem cells.

Chlorella vulgaris treatment ameliorates the suppressive effects of single and repeated stressors on hematopoiesis.

The reports regarding the mutual influence between the central nervous system and the immune system constitute a vast and somewhat controversial body of literature. Stress is known to disturb homeostasis, impairing immunological functions. In this study, we investigated the hematopoietic response of Chlorella vulgaris (CV)-treated mice exposed to single (SST) and repeated stress (RST). We observed a reduction in the numbers of hematopoietic progenitors (HP) in the bone marrow and long-term bone marrow cultures (LTBMC) using flow cytometry and a coinciding decrease in the number of granulocyte-macrophage colonies (CFU-GM) after treatment with both stressors, but SST caused a more profound suppression. We observed a proportional increase in the colony-stimulating activity (CSA) of the serum of animals subjected to SST or RST. In the bone marrow, SST and RST induced a decrease in both mature myeloid and lymphoid populations but did not affect pluripotent hematopoietic progenitors (Lin(-)Sca-1(+)c-kit(+), LSK), and again, a more profound suppression was observed after SST. We further quantified the levels of interleukin-1α (IL-1α) and interleukin-6 (IL-6) and the number of myeloid cells in LTBMC. Both SST and RST reduced the levels of these cytokines to similar degrees. The myeloid population was also reduced in LTBMC, and SST induced a more intense suppression. Importantly, CV treatment prevented the changes produced by SST and RST in all of the parameters evaluated. Together, our results suggest that CV treatment is an effective tool for the prophylaxis of myelosuppression caused by single or repeated stressors.

Autophagy inhibited Ehrlich ascitic tumor cells apoptosis induced by the nitrostyrene derivative compounds: relationship with cytosolic calcium mobilization.

Apoptosis induction is often associated with increased autophagy, indicating interplay between these two important cellular events in cell death and survival. In this study, the programmed cell death and autophagy induced by two nitrostyrene derivative compounds (NTS1 and NTS2) was studied using the tumorigenic Ehrlich ascitic tumor (EAT) cells. EAT cells were highly sensitive to NTS1 and NTS2 cytotoxicity in a dose-dependent manner. NTS1 and NTS2 IC(50) was less than 15.0µM post 12h incubation. Apoptosis was primarily induced by both compounds, as demonstrated by an increase in Annexin-V positive cells, concurrently with cytochrome c release from mitochondria to cytosol and caspase-3 activation. Although cytosolic Ca(2+) mobilization is involved in autophagy as well as apoptosis in response to cellular stress in many cancer cell types, from the two nitrostyrene derivative compounds studied, mainly NTS1 mobilized this ion and disparate autophagy in EAT cells. These results suggest that EAT induced cell death by NTS1 and NTS2 involved a Ca(2+)-dependent and a Ca(2+)-independent pathways, respectively. In accordance with these results, the treatment of EAT cells with 3 methyladenine (3-MA), an autophagy inhibitor; significantly increased the number of apoptotic cells after NTS1 treatment, suggesting that pharmacological modulation of autophagy augments the NTS1 efficacy. Thus, we denote the importance of studies involving autophagy and apoptosis during pre-clinical studies of new drugs with anticancer properties.

Calcium signaling as a regulator of hematopoiesis.

Different extracellular signaling molecules that bind to receptors on the cell membrane use calcium ions for signal transduction. Due to the opening of receptor-operated calcium channels, some cytokine receptors and G-protein coupled receptors induce an increase of intracellular calcium concentration upon activation. Calcium ion is a versatile intracellular secondary messenger that control many different cellular functions by changing its cytoplasmic concentration. A specific and complex network of signaling proteins recognizes intracellular calcium alterations to modulate cellular processes. Some reports have previously demonstrated that calcium also regulates hematopoiesis. This review examines the participation of intracellular calcium in hematopoiesis after the stimulus of various myeloid cytokines such as interleukin-3 and granulocyte-macrophage colony-stimulating factor. In addition, the role of adenosine triphosphate and its receptors in inducing calcium increases during hematopoiesis is discussed. Lastly, the participation of this ion in myeloid proliferation and differentiation by cytokines and P2 receptors is also discussed.