Canine leishmaniasis: evolution of the chemotherapeutic protocols

Dogs are the domestic reservoir for Leishmania infantum (syn.: L. chagasi), the parasite causing zoonotic visceral leishmaniasis (ZVL) in both the Old and New Worlds. In foci of canine leishmaniasis (CanL), symptomatic disease occurs in less than 50% of infected dogs, and is characterized by chronic evolution of viscero-cutaneous signs. Among strategies recommended to control ZVL, detection and drug treatment of infected dogs are usually employed in the endemic countries of southern Europe. However, the conventional antileishmanial drugs successfully used in human therapy, such as pentavalent antimonials, amphotericin B, pentamidine or miltefosine, have low efficacy in the treatment of CanL. In dogs, these drugs induce only temporary remission of clinical signs, do not prevent occurrence of relapses, and often cause severe side effects. Leishmaniotic dogs may be classified into 4 groups: 1) Asymptomatic resistant dogs ("contacted dogs"), 2) Asymptomatic dogs (preclinical), 3) Dogs with minimal signs of leishmaniasis (oligosymptomatic dogs? Chronic form of leishmaniasis?), 4) Dogs suffering from different forms of clinical leishmaniasis (symptomatic dogs). The dog's immunological status and the associated clinical signs may influence the efficacy of antileishmanial drugs. Subjects belonging to groups 2, 3 and 4 should be always treated, in order to reduce their parasite load. Parameters that must be considered before starting the antileishmanial treatment are hemogram, renal and hepatic functions, electrophoretic protein pattern, antileishmania antibody titres, and bone marrow and lymph node parasite load. The most common antileishmanial drugs currently used in Italy to treat CanL are pentavalent antimonials (meglumine antimoniate) and allopurinol, alone or in combination. Other used drugs are aminosidine (syn.: paromomycin), pentamidine, metronidazole and spyramicin. Each drug regimen has different duration, from a few weeks (aminosidine), to a few months (meglumine antimoniate) or several months (allopurinol). One of the most recent drug used in human VL is liposomal amphotericin B (AmBisome--L-AMB), a powerful antileishmanial drug in both experimental murine models and in VL patients. In Italy, L-AMB is now considered the drug of choice for the treatment of human cases. However, in HIV co-infected patients high doses of L-AMB are ineffective in obtaining a radical cure. In dogs, L-AMB treatment rapidly leads to clinical recovery but is uneffective to eliminate the parasites. Drugs containing amphotericin B should not be used in veterinary practice in order to avoid selection of parasites resistant to the drug, as it already occurred for the pentavalent antimonials. Currently, there is not a standard protocol for CanL treatment in Italy, as there is an extreme variability of proposed dosages. Clinical studies on immunotherapeutics and new antileishmanial drugs, such as miltefosine and its derivates, are in progress.     

Leishmania infantum infection rates in Phlebotomus perniciosus fed on naturally infected dogs under antimonial treatment

Dogs naturally infected with Leishmania infantum Nicolle were treated with three courses of meglumine antimoniate. Changes were observed in the dogs' clinical signs, antibody titres and in infection rates of Phlebotomus perniciosus Newstead fed on the dogs. A large reduction in the sandfly infection rate was observed for 4-5 months after the first treatment. The use of antimonial drugs is advocated for the control of canine leishmaniasis and to reduce risks of L.infantum transmission.     

Canine leishmaniosis in Tunisia: Growing prevalence,larger zones of infection

BackgroundDiscovered by Nicolle and Comte in 1908 in Tunisia, Leishmania infantum is an intracellular protozoan responsible for zoonotic canine leishmaniosis (CanL) and zoonotic human visceral leishmaniasis (HVL). It is endemic in several regions of the world, including Tunisia, with dogs considered as the main domestic reservoir. The geographic expansion of canine leishmaniosis (CanL) has been linked to global environmental changes that have affected the density and the distribution of its sand fly vectors.Methodology/Principal findingsIn this study, a cross-sectional epidemiological survey on CanL was carried out in 8 localities in 8 bioclimatic areas of Tunisia. Blood samples were taken from 317 dogs after clinical examination. Collected sera were tested by indirect fluorescent antibody test (IFAT; 1:80) for the presence of anti-Leishmania infantum antibodies. The overall seroprevalence was 58.3% (185/317). Among positive dogs, only 16.7% showed clinical signs suggestive of leishmaniosis. Seroprevalence rates varied from 6.8% to 84.6% and from 28% to 66% by bioclimatic zone and age group, respectively. Serological positivity was not statistically associated with gender. The presence of Leishmania DNA in blood, using PCR, revealed 21.2% (64/302) prevalence in dogs, which varied by bioclimatic zone (7.3% to 31%) and age group (7% to 25%). The entomological survey carried out in the studied localities showed 16 species of the two genera (Phlebotomus and Sergentomyia). P. perniciosus, P. papatasi, and P. perfiliewi were the most dominant species with relative abundances of 34.7%, 25% and 20.4%, respectively.Conclusions/SignificanceThe present report suggests a significant increase of CanL in all bioclimatic areas in Tunisia and confirms the ongoing spread of the infection of dogs to the country’s arid zone. Such an expansion of infection in dog population could be attributed to ecological, agronomic, social and climatic factors that affect the presence and density of the phlebotomine vectors.     

Sensitivity of Leishmania braziliensis promastigotes to meglumine antimoniate (glucantime) is higher than that of other Leishmania species and correlates with response to therapy in American tegumentary leishmaniasis

The first line drugs for the treatment of leishmaniasis are antimonial derivatives. Poor clinical response may be credited to factors linked to the host, the drug, or the parasite. We determined the sensitivity of Leishmania sp. promastigotes and amastigotes by counting parasites exposed to increasing concentrations of meglumine antimoniate (Glucantime). Leishmania braziliensis promastigotes were significantly more sensitive than those belonging to other species. The sensitivity of L. braziliensis isolates from patients with unfavorable clinical outcome, such as therapeutic failure or relapse, was significantly lower than those from patients who had clinical cure. Poor clinical response to therapy (therapeutic failure or relapse) was also associated with inadequate antimonial therapy. We also found a significant and positive correlation between promastigotes and intracellular amastigotes with regard to their in vitro susceptibilities to meglumine antimoniate. Our data provide evidence for an association between the sensitivity of promastigotes to antimonials in vitro and clinical response to therapy in American tegumentary leishmaniasis. The high sensitivity of the local L. braziliensis to meglumine antimoniate in vitro provides an explanation for the good clinical response of cutaneous leishmaniasis in the municipality of Rio de Janeiro, Brazil, even when low-dose regimens are employed.     

Allopurinol Resistance in Leishmania infantum from Dogs with Disease Relapse

Background

Visceral leishmaniasis caused by the protozoan Leishmania infantum is a zoonotic, life threatening parasitic disease. Domestic dogs are the main peridomestic reservoir, and allopurinol is the most frequently used drug for the control of infection, alone or in combination with other drugs. Resistance of Leishmania strains from dogs to allopurinol has not been described before in clinical studies.

Methodology/Principal Findings

Following our observation of clinical disease relapse in dogs under allopurinol treatment, we tested susceptibility to allopurinol of L. infantum isolated from groups of dogs pre-treatment, treated in remission, and with disease relapse during treatment. Promastigote isolates obtained from four treated relapsed dogs (TR group) showed an average half maximal inhibitory concentration (IC50) of 996 μg/mL. A significantly lower IC50 (P = 0.01) was found for isolates from ten dogs before treatment (NT group, 200 μg/mL), as well as for five isolates obtained from treated dogs in remission (TA group, 268 μg/mL). Axenic amastigotes produced from isolates of the TR group also showed significantly higher (P = 0.002) IC50 compared to the NT group (1678 and 671 μg/mL, respectively). The lower sensitivity of intracellular amastigotes from the TR group relative to those from the NT group (P = 0.002) was confirmed using an infected macrophage model (6.3% and 20% growth inhibition, respectively at 300 μg/mL allopurinol).

Conclusions

This is the first study to demonstrate allopurinol resistance in L. infantum and to associate it with disease relapse in the canine host. These findings are of concern as allopurinol is the main drug used for long term control of the disease in dogs, and resistant L. infantum strains may enhance uncontrolled transmission to humans and to other dogs.     

Protocol for the Arterial Revascularisation Trial (ART). A randomised trial to compare survival following bilateral versus single internal mammary grafting in coronary revascularisation [ISRCTN46552265]

Background

Cutaneous Leishmaniasis is a worldwide disease, endemic in 88 countries, that has shown an increasing incidence over the last two decades. So far, pentavalent antimony compounds have been considered the treatment of choice, with a percentage of cure of about 85%. However, the high efficacy of these drugs is counteracted by their many disadvantages and adverse events. Previous studies have shown nitric oxide to be a potential alternative treatment when administered topically with no serious adverse events. However, due to the unstable nitric oxide release, the topical donors needed to be applied frequently, making the adherence to the treatment difficult. The electrospinning technique has allowed the production of a multilayer transdermal patch that produces a continuous and stable nitric oxide release. The main objective of this study is to evaluate this novel nitric oxide topical donor for the treatment of cutaneous leishmaniasis.

Methods and design

A double-blind, randomized, double-masked, placebo-controlled clinical trial, including 620 patients from endemic areas for Leishmaniasis in Colombia was designed to investigate whether this patch is as effective as meglumine antimoniate for the treatment of cutaneous leishmaniasis but with less adverse events. Subjects with ulcers characteristic of cutaneous leishmaniasis will be medically evaluated and laboratory tests and parasitological confirmation performed. After checking the inclusion/exclusion criteria, the patients will be randomly assigned to one of two groups. During 20 days Group 1 will receive simultaneously meglumine antimoniate and placebo of nitric oxide patches while Group 2 will receive placebo of meglumine antimoniate and active nitric oxide patches. During the treatment visits, the medications will be daily administered and the presence of adverse events assessed. During the follow-up, the research group will visit the patients at days 21, 45, 90 and 180. The healing process of the ulcer, the health of the participants, recidivisms and/or reinfection will also be assessed. The evolution of the ulcers will be photographically registered. In case that the effectiveness of the patches is demonstrated, a novel and safe therapeutic alternative for one of the most important public health problems in many countries will be available to patients.     

Leishmania infection and host-blood feeding preferences of phlebotomine sandflies and canine leishmaniasis in an endemic European area,the Algarve Region in Portugal

The Algarve Region (AR) in southern Portugal, which is an international tourist destination, has been considered an endemic region of zoonotic leishmaniasis caused by Leishmania infantum since the 1980s. In the present study, phlebotomine and canine surveys were conducted to identify sandfly blood meal sources and to update the occurrence of Leishmania infection in vectors and dogs. Four sandfly species were captured: Phlebotomus perniciosus, Phlebotomus ariasi, Phlebotomus sergenti and Sergentomyia minuta. In one P. perniciosus female, L. infantum DNA was detected. Blood meal tests showed that this species had no host preferences and was an opportunistic feeder. An overall canine leishmaniasis (CanL) seroprevalence of 16.06% was found; the seroprevalence was 3.88% in dogs housed in kennels and 40.63% in dogs that attended veterinary clinics. The simultaneous occurrence of dogs and P. perniciosus infected with L. infantum in the AR indicates that the region continues to be an endemic area for CanL. Our results reinforce the need for the systematic spatial distribution of phlebotomine populations and their Leishmania infection rates and the need to simultaneously perform pathogen monitoring in both invertebrate and vertebrate hosts to investigate the transmission, distribution and spreading of Leishmania infection.     

Pediatric Visceral Leishmaniasis in Albania: A Retrospective Analysis of 1,210 Consecutive Hospitalized Patients (1995–2009)

Background

Little information is available about infantile visceral leishmaniasis (VL) in Albania as regards incidence, diagnosis and management of the disease.

Methodology/Principal Findings

Demographic data, clinical and laboratory features and therapeutic findings were considered in children admitted to University Hospital of Tirana from 1995 to 2009, and diagnosed as having VL. The diagnosis was based on bone-marrow microscopy/culture in 77.5% of patients, serology in 16.1%, and ex juvantibus in 6.4%. A total of 1,210 children were considered, of whom 74% came from urbanized areas. All patients were in the age range 0–14 years, with a median of 4 years. Hepatosplenomegaly was recorded in 100%, fever in 95.4% and moderate to severe anemia in 88% of cases. Concomitant conditions were frequent: 84% had bronchopneumonia; diarrhea was present in 27%, with acute manifestations in 5%; 3% had salmonellosis. First-line therapy was meglumine antimoniate for all patients, given at the standard Sb^v dosage of 20 mg/kg/day for 21 to 28 days. Two children died under treatment, one of sepsis, the other of acute renal impairment. There were no cases of primary unresponsiveness to treatment, and only 8 (0.67%) relapsed within 6–12 months after therapy. These patients have been re-treated with liposomal amphotericin B, with successful cure.

Conclusions

Visceral leishmaniasis in pediatric age is relatively frequent in Albania; therefore an improvement is warranted of a disease-specific surveillance system in this country, especially as regards diagnosis. Despite recent reports on decreased responses to antimonial drugs of patients with Mediterranean VL, meglumine antimoniate treatment appears to be still highly effective in Albania.     

Evidence for an impact on the incidence of canine leishmaniasis by the mass use of deltamethrin-impregnated dog collars in southern Italy

Dogs are the domestic reservoir of Leishmania infantum Nicolle (Kinetoplastida: Trypanosomatidae), the agent of zoonotic human visceral leishmaniasis. In southern Europe, where canine leishmaniasis (CanL) is widespread due to L. infantum, killing seropositive dogs is considered unacceptable and drug treatment has low efficacy in preventing transmission. We made a field evaluation of the efficacy of deltamethrin dog collars in a CanL focus of southern Italy, Mount Vesuvius area of Campania region, where the vector is Phlebotomus perniciosus Newstead (Diptera: Psychodidae), by assessing their impact on the incidence of CanL in an intervention town, compared to that in dogs of control towns where no collars were fitted. During two consecutive transmission seasons, collars were fitted to 350 (1998) and 354 (1999) dogs from San Sebastiano al Vesuvio (70% of the canine population). Control dogs (371 and 264 in the 2 years, respectively) were from four towns of the same area. Before each transmission season, the CanL seroprevalence in the intervention and control towns was evaluated by cross-sectional surveys and found to be similar (about 15% in 1998 and 10% in 1999, respectively). After each transmission period, incidence rates of seroconversions were determined in adult dogs that were serologically negative before the season under evaluation, and in puppies. After the 1998 season, 2.7% of the dogs in the intervention town seroconverted compared to 5.4% in the control towns (50% protection, P = 0.15). After the 1999 season, 3.5% of collared dogs seroconverted compared to 25.8% of control dogs (86% protection, P < 0.001). The increase in seroconversion rates recorded in control dogs suggests an increase in the Leishmania force of infection in the canine reservoir during the 1999 sandfly season, as supported by the concomitant increase of human cases in control towns and in the whole Campania region. Our results suggest that the impact of mass use of deltamethrin-impregnated dog collars on the incidence of CanL may be negligible during low transmission seasons, or probably in low endemic foci, but can be very strong when the force of transmission is high.     

Estimation of Canine Leishmania Infection Prevalence in Six Cities of the Algerian Littoral Zone Using a Bayesian Approach

A large-scale study on canine Leishmania infection (CanL) was conducted in six localities along a west-east transect in the Algerian littoral zone (Tlemcen, Mostaganem, Tipaza, Boumerdes, Bejaia, Jijel) and covering two sampling periods. In total 2,184 dogs were tested with an indirect fluorescent antibody test (IFAT) and a direct agglutination test (DAT). Combined multiple-testing and several statistical methods were compared to estimate the CanL true prevalence and tests characteristics (sensitivity and specificity). The Bayesian full model showed the best fit and yielded prevalence estimates between 11% (Mostaganem, first period) and 38% (Bejaia, second period). Sensitivity of IFAT varied (in function of locality) between 86% and 88% while its specificity varied between 65% and 87%. DAT was less sensitive than IFAT but showed a higher specificity (between 80% and 95% in function of locality or/and season). A general increasing trend of the CanL prevalence was noted from west to east. A concordance between the present results and the incidence of human cases of visceral leishmaniasis was observed, where also a maximum was recorded for Bejaia. The results of the present study highlight the dangers when using IFAT as a gold standard.     

Role of residual Sb(III) in meglumine antimoniate cytotoxicity and MRP1-mediated resistance

Despite the clinical use of pentavalent antimonials for more than half a century, their metabolism in mammals and mechanisms of action and toxicity remain poorly understood. It has been proposed that the more active and toxic trivalent antimony form Sb(III) plays a critical role in their antileishmanial activity and toxicity. The aim of this work was to investigate the role of residual Sb(III) both in the antileishmanial/antitumoral activities of the pentavalent meglumine antimoniate and in the MRP1 (multidrug resistance-associated protein 1)-mediated resistance to this drug. Samples of meglumine antimoniate differing in their amount of residual Sb(III) (meglumine antimoniate synthesized either from SbCl₅ or from KSb(OH)₆ as well as commercially-available meglumine antimoniate) were evaluated in vitro and in vivo on Leishmania amazonensis infections, as well as for their cytotoxicity to normal and MRP1-overexpressing GLC4 cell lines. Although in vitro the two most effective drugs contained the highest levels of Sb(III), no correlation was found in vivo between the antileishmanial activity of meglumine antimoniate and its residual Sb(III) content, suggesting that residual Sb(III) contributes only marginally to the drug antileishmanial activity. On the other hand, the GLC4 cells growth inhibition data strongly suggests a marked contribution of residual Sb(III). Additionally, the potassium salt of antimoniate (non-complexed form of Sb(V)) was found to be more cytotoxic than meglumine antimoniate. Although MRP1-overexpressing GLC4 cells showed a marked resistance to trivalent antimonials, cross-resistance to meglumine antimoniate was observed only for the products that contained relatively high levels of Sb(III) (at least 0.03% by weight), suggesting that MRP1 mediates resistance to Sb(III) but not to Sb(V). In conclusion, our data strongly suggest that residual Sb(III) in pentavalent antimonial drugs does not contribute significantly to their antileishmanial activity, but is responsible for their cytotoxic activity against mammalian cells and the MRP1-mediated resistance to these drugs.     

Miltefosine and Antimonial Drug Susceptibility of Leishmania Viannia Species and Populations in Regions of High Transmission in Colombia

Background

Pentavalent antimonials have been the first line treatment for dermal leishmaniasis in Colombia for over 30 years. Miltefosine is administered as second line treatment since 2005. The susceptibility of circulating populations of Leishmania to these drugs is unknown despite clinical evidence supporting the emergence of resistance.

Methodology/Principal Findings

In vitro susceptibility was determined for intracellular amastigotes of 245 clinical strains of the most prevalent Leishmania Viannia species in Colombia to miltefosine (HePC) and/or meglumine antimoniate (Sb^V); 163, (80%) were evaluated for both drugs. Additionally, susceptibility to Sb^V was examined in two cohorts of 85 L. V. panamensis strains isolated between 1980–1989 and 2000–2009 in the municipality of Tumaco. Susceptibility to each drug differed among strains of the same species and between species. Whereas 68% of L. V. braziliensis strains presented in vitro resistance to HePC, 69% were sensitive to Sb^V. Resistance to HePC and Sb^V occurred respectively, in 20% y 21% of L. panamensis strains. Only 3% of L. V. guyanensis were resistant to HePC, and none to Sb^V. Drug susceptibility differed between geographic regions and time periods. Subpopulations having disparate susceptibility to Sb^V were discerned among L. V. panamensis strains isolated during 1980–1990 in Tumaco where resistant strains belonged to zymodeme 2.3, and sensitive strains to zymodeme 2.2.

Conclusions/Significance

Large scale evaluation of clinical strains of Leishmania Viannia species demonstrated species, population, geographic, and epidemiologic differences in susceptibility to meglumine antimoniate and miltefosine, and provided baseline information for monitoring susceptibility to these drugs. Sensitive and resistant clinical strains within each species, and zymodeme as a proxy marker of antimony susceptibility for L. V. panamensis, will be useful in deciphering factors involved in susceptibility and the distribution of sensitive and resistant populations.     

Risk factors for antimony treatment failure in American Cutaneous Leishmaniasis in Northwestern-Argentina

Background. To date, there is no specific literature available on the determinants for therapeutic failure (TF) with meglumine antimoniate (MA) in Northwestern-Argentina. This study aimed to identify epidemiological, clinical, and treatment-related factors that could be involved in TF. Methodology/Principal Findings. We performed a case-control study. Cases were represented by patients who showed TF after administration of the first course of MA treatment, whereas, controls were determined as patients who evolved towards healing after the first MA cycle received. Crude Odds Ratios and their corresponding 90% confidence intervals (CI) were calculated, and risk factors were then tested by multivariate analysis using logistic binary regression. Three hundred and eighty-four patients with a presumptive diagnosis of ACL were recruited, and 153 with a positive diagnosis were selected. We included in the study 71 patients, who underwent specific treatment with MA, presented complete data on response to treatment, and had a minimum post-treatment follow-up of 6 months in cutaneous leishmaniasis, and 12 months in mucosal leishmaniasis. Of these, 34 (47.9%) presented TF. In the initial analysis, TF was significantly associated with the geographical area of disease acquisition (p = 0.036), the presence of mucosal lesions (p = 0.042), the presence of concomitant skin and mucosal lesions (p = 0.002), and lesion age ≥ 6 months (p = 0.018). Risk factors influencing TF in the final multivariate model included the geographical area where the disease was acquired (adjusted Odd Ratio 8.062; 95% CI 1.914–33.959; p = 0.004), and lesion age ≥ 6 months (adjusted Odd Ratio 10.037; 95% CI 1.383–72.843; p = 0.023). Conclusions/Significance. The results of the present study suggest the existence of some risk factors linked to TF in Northwestern-Argentina, which deserve further investigation. Herein we recorded a high percentage of TF and we described clinical and epidemiological characteristics associated with TF that could be taken into account improving the clinical management of patients.     

Antimony Containing Drug and ECG Abnormalities in Children with Visceral Leishmaniasis

The objective of the paper was to evaluate the influence of antimony (5⁺) on electrocardiographic changes in children with visceral leishmaniasis. The study was based on weekly ECGs analysis of 87 children treated, from April 2001 to May 2006, with antimoniate N-methyl glucamine. Eligible subjects included children from 6 months to 12 years of age with weight of 6–34 kg. Forty-five children (52%) were males and forty-two (48%) were females. The cardiac response to antimony was significantly milder compared to the adult populations, so the usage of meglumine antimoniate is safer. Thus, during treatment sinus rhythm was maintained without ectopic beats. No changes were observed in the P wave and in PR interval. The QRS complex remained unaltered during the treatment, the amplitude being increased. The Sokolow`s indexes exceeded normal values in one child on the first week and in eight children on the fourth. The prolongation of QTc occurred in ten patients. The T wave flattening was observed in seven children on the first week. In total, ECG abnormalities were detected in 34.4% of treatment courses, while in adults they were reported in 53.8%. Antimony therapy needs ECG monitoring of the cardiac function in order to prevent complications.     

青蒿琥酯对肺癌细胞裸鼠皮下移植瘤生长和放射敏感性的影响研究

目的:探讨青蒿琥酯对肺癌细胞裸鼠皮下移植瘤生长和放射敏感性的影响。方法:将肺癌细胞接种至裸鼠皮下,腹腔注射青蒿琥酯,同时给予放射处理记为联合组,设置青蒿琥酯组(不照射处理)、放射组(腹腔注射生理盐水)和对照组(腹腔注射生理盐水,不放射处理),测量肿瘤体积,取瘤体并称取瘤体重量,脱氧核糖核苷酸末端转移酶介导的缺口末端标记法(TUNEL)法检测组织中细胞凋亡水平,Western blot检测组织中活化的含半胱氨酸的天冬氨酸蛋白水解酶3(Cleaved Caspase-3)、信号转导与转录因子3(STAT3)、磷酸化的STAT3(p-STAT3)、p38丝裂原活化蛋白激酶(p38MAPK)、磷酸化的p38MAPK(p-p38MAPK)水平。结果:青蒿琥酯组、放射组、联合组皮下移植瘤体积和重量均明显低于对照组,联合组肿瘤重量和体积明显低于青蒿琥酯和放射组,差异均具有统计学意义(P0.05)。青蒿琥酯、放射组、联合组肿瘤组织中细胞凋亡率、Cleaved Caspase-3水平和p-p38MAPK/p38MAPK均明显高于对照组,联合组肿瘤组织中细胞凋亡率、Cleaved Caspase-3水平和p-p38MAPK/p38MAPK高于青蒿琥酯和放射组,差异均具有统计学意义(P0.05)。青蒿琥酯、放射组、联合组肿瘤组织中p-STAT3/STAT3水平明显低于对照组,联合组肿瘤组织中p-STAT3/STAT3水平低于蒿琥酯组和放射组,差异均具有统计学意义(P0.05)。结论:青蒿琥酯能够抑制肺癌细胞裸鼠皮下移植瘤生长,促进癌细胞凋亡,增加放疗敏感性,作用机制可能与p38MAPK、STAT3信号通路有关。     

High frequency of skin reactions in patients with leishmaniasis treated with meglumine antimoniate contaminated with heavy metals: a comparative approach using historical controls

We analyzed data from historical controls treated with meglumine antimoniate to compare the frequency of adverse events observed in patients with cutaneous leishmaniasis treated with the same dose of meglumine antimoniate contaminated with heavy metals in an endemic area of the State of Bahia, Brazil. Group A patients were treated in 2000 with the drug produced by Eurofarma Laborat rios Ltda., S o Paulo, Brazil (lot A) and group B patients were treated in 1996 with the reference drug produced by Rhodia Farma Ltda., S o Paulo, Brazil (lot B). We observed an unusual higher frequency of skin reactions in group A patients. However, all type of adverse events observed in group A were also observed in group B. The physico-chemical analysis of these lots revealed that lot A had lower pH and higher concentration of total and trivalent antimony, lead, cadmium, and arsenic. Our findings suggest that the skin reactions could be attributed to heavy metal contamination of lot A.     

Use of a Recombinant Cysteine Proteinase from Leishmania (Leishmania) infantum chagasi for the Immunotherapy of Canine Visceral Leishmaniasis

Background

A recombinant cysteine proteinase from Leishmania (Leishmania) infantum chagasi (rLdccys1) was previously shown to induce protective immune responses against murine and canine visceral leishmaniasis. These findings encouraged us to use rLdccys1 in the immunotherapy of naturally infected dogs from Teresina, Piauí, a region of high incidence of visceral leishmaniasis in Brazil.

Methodology/Principal Findings

Thirty naturally infected mongrel dogs displaying clinical signs of visceral leishmaniasis were randomly divided in three groups: one group received three doses of rLdccys1 in combination with the adjuvant Propionibacterium acnes at one month interval between each dose; a second group received three doses of P. acnes alone; a third group received saline. The main findings were: 1) dogs that received rLdccys1 with P. acnes did not display increase of the following clinical signs: weight loss, alopecia, onychogryphosis, cachexia, anorexia, apathy, skin lesions, hyperkeratosis, ocular secretion, and enlarged lymph nodes; they also exhibited a significant reduction in the spleen parasite load in comparison to the control dogs; 2) rLdccys1-treated dogs exhibited a significant delayed type cutaneous hypersensitivity elicited by the recombinant antigen, as well as high IgG2 serum titers and low IgG1 serum titers; sera from rLdccys1-treated dogs also contained high IFN-γ and low IL-10 concentrations; 3) control dogs exhibited all of the clinical signs of visceral leishmaniasis and had low serum IgG2 and IFN-γ levels and high concentrations of IgG1 and IL-10; 4) all of the dogs treated with rLdccys1 were alive 12 months after treatment, whereas dogs which received either saline or P. acnes alone died within 3 to 7 months.

Conclusions/Significance

These findings illustrate the potential use of rLdccys1 as an additional tool for the immunotherapy of canine visceral leishmaniasis and support further studies designed to improve the efficacy of this recombinant antigen for the treatment of this neglected disease.     

Visceral Leishmaniasis without Fever in an 11-Month-Old Infant: a Rare Clinical Feature of Kala-azar

Visceral leishmaniasis or kala-azar is an endemic parasitic disease in some parts of the world which is characterized by fever, splenomegaly, and pancytopenia in most of the cases. Herein we report an 11 month-old male infant with diagnosis of kala-azar who presented with pallor, hepatosplenomegaly, failure to gain weight, and no history of fever. Surprisingly, fever started after beginning of meglumine antimoniate treatment in this patient. As far as we are aware of, this is a rare presentation of visceral leishmaniasis. Therefore, clinicians especially in endemic areas are highly recommended to include kala-azar among differential diagnosis of unexplained anemia without fever to prevent misdiagnosis of this potentially fatal, but treatable condition.     

Anti-malarial drug artesunate protects against cigarette smoke-induced lung injury in mice

Cigarette smoking is the primary cause of chronic obstructive pulmonary disease (COPD), which is mediated by lung infiltration with inflammatory cells, enhanced oxidative stress, and tissue destruction. Anti-malarial drug artesunate has been shown to possess anti-inflammatory and anti-oxidative actions in mouse asthma models. We hypothesized that artesunate can protect against cigarette smoke-induced acute lung injury via its anti-inflammatory and anti-oxidative properties. Artesunate was given by oral gavage to BALB/c mice daily 2 h before 4% cigarette smoke exposure for 1 h over five consecutive days. Bronchoalveolar lavage (BAL) fluid and lungs were collected for analyses of cytokines, oxidative damage and antioxidant activities. Bronchial epithelial cell BEAS-2B was exposed to cigarette smoke extract (CSE) and used to study the mechanisms of action of artesunate. Artesunate suppressed cigarette smoke-induced increases in BAL fluid total and differential cell counts; levels of IL-1β, MCP-1, IP-10 and KC; and levels of oxidative biomarkers 8-isoprostane, 8-OHdG and 3-nitrotyrosine in a dose-dependent manner. Artesunate promoted anti-oxidant catalase activity and reduced NADPH oxidase 2 (NOX2) protein level in the lungs from cigarette smoke-exposed mice. In BEAS-2B cells, artesunate suppressed pro-inflammatory PI3 K/Akt and p44/42 MAPK signaling pathways, and increased nuclear Nrf2 accumulation in response to CSE. Artesunate possesses anti-inflammatory and anti-oxidative properties against cigarette smoke-induced lung injury, probably via inhibition of PI3K and p42/22 MAPK signaling pathways, augmentation of Nrf2 and catalase activities, and reduction of NOX2 level. Our data suggest that artesunate may have therapeutic potential for treating COPD.