Skin pharmacokinetics of miltefosine in the treatment of post-kala-azar dermal leishmaniasis in South Asia.

INTRODUCTION: Post-kala-azar dermal leishmaniasis (PKDL) arises as a dermal complication following a visceral leishmaniasis (VL) infection. Current treatment options for PKDL are unsatisfactory, and there is a knowledge gap regarding the distribution of antileishmanial compounds within human skin. The present study investigated the skin distribution of miltefosine in PKDL patients, with the aim to improve the understanding of the pharmacokinetics at the skin target site in PKDL. METHODS: Fifty-two PKDL patients underwent treatment with liposomal amphotericin B (20 mg/kg) plus miltefosine (allometric dosing) for 21 days. Plasma concentrations of miltefosine were measured on study days 8, 15, 22 and 30, while a punch skin biopsy was taken on day 22. A physiologically based pharmacokinetic (PBPK) model was developed to evaluate the distribution of miltefosine into the skin. RESULTS: Following the allometric weight-based dosing regimen, median miltefosine concentrations on day 22 were 43.73 µg/g (IQR: 21.94-60.65 µg/g) in skin and 33.29 µg/mL (IQR: 25.9-42.58 µg/mL) in plasma. The median individual concentration ratio of skin to plasma was 1.19 (IQR: 0.79-1.9). In 87% (45/52) of patients, skin exposure was above the suggested EC90 PK target of 10.6 mg/L associated with in vitro susceptibility. Simulations indicated that the residence time of miltefosine in the skin would be more than 2-fold longer than in plasma, estimated by a mean residence time of 604 versus 266 hours, respectively. CONCLUSION: This study provides the first accurate measurements of miltefosine penetration into the skin, demonstrating substantial exposure and prolonged retention of miltefosine within the skin. These findings support the use of miltefosine in cutaneous manifestations of leishmaniasis. In combination with parasitological and clinical data, these results are critical for the future optimization of combination therapies with miltefosine in the treatment of PKDL.

Redox-Responsive Nanocapsules for the Spatiotemporal Release of Miltefosine in Lysosome: Protection against Leishmania.

Leishmaniasis, a vector-borne disease, is caused by intracellular parasite Leishmania donovani. Unlike most intracellular pathogens, Leishmania donovani are lodged in parasitophorous vacuoles and replicate within the phagolysosomes in macrophages. Effective vaccines against this disease are still under development, while the efficacy of the available drugs is being questioned owing to the toxicity for nonspecific distribution in human physiology and the reported drug-resistance developed by Leishmania donovani. Thus, a stimuli-responsive nanocarrier that allows specific localization and release of the drug in the lysosome has been highly sought after for addressing two crucial issues, lower drug toxicity and a higher drug efficacy. We report here a unique lysosome targeting polymeric nanocapsules, formed via inverse mini-emulsion technique, for stimuli-responsive release of the drug miltefosine in the lysosome of macrophage RAW 264.7 cell line. A benign polymeric backbone, with a disulfide bonding susceptible to an oxidative cleavage, is utilized for the organelle-specific release of miltefosine. Oxidative rupture of the disulfide bond is induced by intracellular glutathione (GSH) as an endogenous stimulus. Such a stimuli-responsive release of the drug miltefosine in the lysosome of macrophage RAW 264.7 cell line over a few hours helped in achieving an improved drug efficacy by 200 times as compared to pure miltefosine. Such a drug formulation could contribute to a new line of treatment for leishmaniasis.

Oral combination of eugenol oleate and miltefosine induce immune response during experimental visceral leishmaniasis through nitric oxide generation with advanced cytokine demand.

Conventional therapy of visceral leishmaniasis (VL) remains challenging with the pitfall of toxicity, drug resistance, and expensive. Hence, urgent need for an alternative approach is essential. In this study, we evaluated the potential of combination therapy with eugenol oleate and miltefosine in Leishmania donovani infected macrophages and in the BALB/c mouse model. The interactions between eugenol oleate and miltefosine were found to be additive against promastigotes and amastigotes with xΣFIC 1.13 and 0.68, respectively. Significantly (p < 0.001) decreased arginase activity, increased nitrite generation, improved pro-inflammatory cytokines, and phosphorylated p38MAPK were observed after combination therapy with eugenol oleate and miltefosine. >80% parasite clearance in splenic and hepatic tissue with concomitant nitrite generation, and anti-VL cytokines productions were observed after orally administered miltefosine (5 mg/kg body weight) and eugenol oleate (15 mg/kg body weight) in L. donovani-infected BALB/c mice. Altogether, this study suggested the possibility of an oral combination of miltefosine with eugenol oleate against visceral leishmaniasis.

In vivo evaluation of anti-Leishmania activity of alkyltriazoles and alkylphosphocholines by oral route.

The failures in the treatment of leishmaniasis is an increasing problem around the world, especially related to resistance. Thus, we describe the synthesis and in vivo anti-Leishmania activity of alkylphosphocholine and alkyltriazoles; besides, their likely action mechanisms stem from some eventual inhibition of parasite enzymes using computational tools. These compounds were tested in an in vivo hamster model infected with Leishmania Leishmania infantum chagasi. Fifty days after parasite inoculation, the two compounds 12-azidedodecylphosphocholine (3) and 3-(1-(12-fluorododecyl)-1H-1,2,3-triazol-1-yl)propano-1-ol (9), were separately administered once a day as oral suspensions (25 and 12.5 mg/kg/day, respectively) during ten days, and their efficacy was compared to the reference compound pentavalent antimonial Glucantime (GLU). Compound 3 significantly reduced the number of parasites in the spleen (4.93 × 102 amastigotes/g) and liver (4.52 × 103 amastigotes/g). Compound 9 reduced the number of amastigotes in the spleen to 1.30 × 104 and 1.36 × 103 amastigotes/g in the liver. GLU was the most effective overall treatment (7.50 × 101 and 2.28 × 102 amastigotes/g in the spleen and liver, respectively). The high activity levels of these compounds in vivo may stem from their high in vitro leishmanicidal activity and lipophilicity. The in silico absorption, distribution, metabolism, and excretion studies also showed some anti-Leishmania potential. Compound 9 had more lipophilic characteristics than those of compound 3. In silico studies of the nine enzymes of compounds 3 and 9 showed significant evidence of interactions with nicotimidase and tyrosine aminotransferase, demonstrating possible inhibition enzymes present in L. (L.) infantum chagasi. These compounds could be a promising template for developing a new class of leishmanicidal agents, by oral route, and deserve further investigation to explore different therapeutic regimens.

Polypyrrole and polyaniline nanocomposites with high photothermal conversion efficiency.

The simple and scalable synthesis of poly[2-(methacryloyloxy)ethyl phosphorylcholine] (PMPC)-coated conducting polymer (CP) nanocomposites is described. These functional nanocomposites exhibit tunable absorption in the near-infrared region with relatively high photothermal efficiencies. More importantly, their potential for bio-imaging and therapeutic treatment is proven by cellular uptake and cytotoxicity studies.

Combination treatment of perifosine and valsartan showed more efficiency in protecting against pressure overload induced mouse heart failure.

The optimum strategy for heart failure (HF) treatment has yet to be elucidated. This study intended to test the benefit of a combination of valsartan (VAL) and perifosine (PER), a specific AKT inhibitor, in protecting against pressure overload induced mouse HF. Mouse were subjected to aortic banding (AB) surgery to establish HF models and then were given vehicle (HF), VAL (50 mg/kg/d), PER (30 mg/kg/d) or combination of VAL and PER for 4 weeks. Mouse with sham surgery treated with VEH were used for control (VEH). VAL or PER treatment could significantly alleviate mouse heart weight, attenuate cardiac fibrosis and improve cardiac function. The combination treatment of VAL and PER presented much better benefit compared with VAL or PER group respectively. PER treatment significantly inhibited AKT/GSK3ß/mTORC1 signaling. Besides the classic AT1 inhibition, VAL treatment significantly inhibited MAPK (ERK1/2) signaling. Furthermore, VAL and PER treatment could markedly prevent neonatal rat cardiomyocyte hypertrophy and the activation of neonatal rat cardiac fibroblast. Combination of VAL and PER also presented superior beneficial effects than single treatment of VAL or PER in vitro experiments respectively. This study presented that the combination of valsartan and PER may be a potential treatment for HF prevention.

Interventions for American cutaneous and mucocutaneous leishmaniasis.

BACKGROUND: On the American continent, cutaneous and mucocutaneous leishmaniasis (CL and MCL) are diseases associated with infection by several species of Leishmania parasites. Pentavalent antimonials remain the first-choice treatment. There are alternative interventions, but reviewing their effectiveness and safety is important as availability is limited. This is an update of a Cochrane Review first published in 2009. OBJECTIVES: To assess the effects of interventions for all immuno-competent people who have American cutaneous and mucocutaneous leishmaniasis (ACML). SEARCH METHODS: We updated our database searches of the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, LILACS and CINAHL to August 2019. We searched five trials registers. SELECTION CRITERIA: Randomised controlled trials (RCTs) assessing either single or combination treatments for ACML in immuno-competent people, diagnosed by clinical presentation and Leishmania infection confirmed by smear, culture, histology, or polymerase chain reaction on a biopsy specimen. The comparators were either no treatment, placebo only, or another active compound. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. Our key outcomes were the percentage of participants 'cured' at least three months after the end of treatment, adverse effects, and recurrence. We used GRADE to assess evidence certainty for each outcome. MAIN RESULTS: We included 75 studies (37 were new), totalling 6533 randomised participants with ATL. The studies were mainly conducted in Central and South America at regional hospitals, local healthcare clinics, and research centres. More male participants were included (mean age: roughly 28.9 years (SD: 7.0)). The most common confirmed species were L. braziliensis, L. panamensis, and L. mexicana. The most assessed interventions and comparators were non-antimonial systemics (particularly oral miltefosine) and antimonials (particularly meglumine antimoniate (MA), which was also a common intervention), respectively. Three studies included moderate-to-severe cases of mucosal leishmaniasis but none included cases with diffuse cutaneous or disseminated CL, considered the severe cutaneous form. Lesions were mainly ulcerative and located in the extremities and limbs. The follow-up (FU) period ranged from 28 days to 7 years. All studies had high or unclear risk of bias in at least one domain (especially performance bias). None of the studies reported the degree of functional or aesthetic impairment, scarring, or quality of life. Compared to placebo, at one-year FU, intramuscular (IM) MA given for 20 days to treat L. braziliensis and L. panamensis infections in ACML may increase the likelihood of complete cure (risk ratio (RR) 4.23, 95% confidence interval (CI) 0.84 to 21.38; 2 RCTs, 157 participants; moderate-certainty evidence), but may also make little to no difference, since the 95% CI includes the possibility of both increased and reduced healing (cure rates), and IMMA probably increases severe adverse effects such as myalgias and arthralgias (RR 1.51, 95% CI 1.17 to 1.96; 1 RCT, 134 participants; moderate-certainty evidence). IMMA may make little to no difference to the recurrence risk, but the 95% CI includes the possibility of both increased and reduced risk (RR 1.79, 95% CI 0.17 to 19.26; 1 RCT, 127 participants; low-certainty evidence). Compared to placebo, at six-month FU, oral miltefosine given for 28 days to treat L. mexicana, L. panamensis and L. braziliensis infections in American cutaneous leishmaniasis (ACL) probably improves the likelihood of complete cure (RR 2.25, 95% CI 1.42 to 3.38), and probably increases nausea rates (RR 3.96, 95% CI 1.49 to 10.48) and vomiting (RR 6.92, 95% CI 2.68 to 17.86) (moderate-certainty evidence). Oral miltefosine may make little to no difference to the recurrence risk (RR 2.97, 95% CI 0.37 to 23.89; low-certainty evidence), but the 95% CI includes the possibility of both increased and reduced risk (all based on 1 RCT, 133 participants). Compared to IMMA, at 6 to 12 months FU, oral miltefosine given for 28 days to treat L. braziliensis, L. panamensis, L. guyanensis and L. amazonensis infections in ACML may make little to no difference to the likelihood of complete cure (RR 1.05, 95% CI 0.90 to 1.23; 7 RCTs, 676 participants; low-certainty evidence). Based on moderate-certainty evidence (3 RCTs, 464 participants), miltefosine probably increases nausea rates (RR 2.45, 95% CI 1.72 to 3.49) and vomiting (RR 4.76, 95% CI 1.82 to 12.46) compared to IMMA. Recurrence risk was not reported. For the rest of the key comparisons, recurrence risk was not reported, and risk of adverse events could not be estimated. Compared to IMMA, at 6 to 12 months FU, oral azithromycin given for 20 to 28 days to treat L. braziliensis infections in ACML probably reduces the likelihood of complete cure (RR 0.51, 95% CI 0.34 to 0.76; 2 RCTs, 93 participants; moderate-certainty evidence). Compared to intravenous MA (IVMA) and placebo, at 12 month FU, adding topical imiquimod to IVMA, given for 20 days to treat L. braziliensis, L. guyanensis and L. peruviana infections in ACL probably makes little to no difference to the likelihood of complete cure (RR 1.30, 95% CI 0.95 to 1.80; 1 RCT, 80 participants; moderate-certainty evidence). Compared to MA, at 6 months FU, one session of local thermotherapy to treat L. panamensis and L. braziliensis infections in ACL reduces the likelihood of complete cure (RR 0.80, 95% CI 0.68 to 0.95; 1 RCT, 292 participants; high-certainty evidence). Compared to IMMA and placebo, at 26 weeks FU, adding oral pentoxifylline to IMMA to treat CL (species not stated) probably makes little to no difference to the likelihood of complete cure (RR 0.86, 95% CI 0.63 to 1.18; 1 RCT, 70 participants; moderate-certainty evidence). AUTHORS' CONCLUSIONS: Evidence certainty was mostly moderate or low, due to methodological shortcomings, which precluded conclusive results. Overall, both IMMA and oral miltefosine probably result in an increase in cure rates, and nausea and vomiting are probably more common with miltefosine than with IMMA. Future trials should investigate interventions for mucosal leishmaniasis and evaluate recurrence rates of cutaneous leishmaniasis and its progression to mucosal disease.

Minimal Cerebrospinal Fluid Concentration of Miltefosine despite Therapeutic Plasma Levels during the Treatment of Amebic Encephalitis.

Miltefosine is an alkylphosphocholine compound that is used primarily for treatment of leishmaniasis and demonstrates in vitro and in vivo antiamebic activity against Acanthamoeba species. Recommendations for treatment of amebic encephalitis generally include miltefosine therapy. Data indicate that treatment with an amebicidal concentration of at least 16 µg/ml of miltefosine is required for most Acanthamoeba species. Although there is a high level of mortality associated with amebic encephalitis, a paucity of data regarding miltefosine levels in plasma and cerebrospinal fluid in vivo exists in the literature. We found that despite aggressive dosing (oral miltefosine 50 mg every 6 h) and therapeutic plasma levels, the miltefosine concentration in cerebrospinal fluid was negligible in a patient with AIDS and Acanthamoeba encephalitis.

Anti-leishmanial activity of a topical miltefosine gel in experimental models of New World cutaneous leishmaniasis.

OBJECTIVES: Topical treatment for cutaneous leishmaniasis (CL) would be useful for treatment of some forms of the disease. The aim of this study was to develop and then evaluate a topical miltefosine gel for anti-leishmanial activity and toxicity in BALB/c mice infected with New World (NW)-CL species. METHODS: A Carbopol-based gel of 0.5% miltefosine was prepared and physicochemical (colour, pH, consistency and antioxidant activity) and stability properties were determined using standard methodologies. Anti-leishmanial activities for Leishmania (Viannia) braziliensis and Leishmania (Viannia) panamensis were determined both in cultured parasites and in infected BALB/c mice after topical miltefosine gel treatment administered for 20 days. The gel was evaluated for its capacity to inhibit parasites at a 50% level after 3 days of treatment in vitro, and its capacity to reduce lesion size (mm2) and parasitic load after 20 days of treatment. Dermal irritation, contact hypersensitivity (CHS), clinical biochemical profile and the weight of the animals were determined after treatment. RESULTS: The 0.5% miltefosine gel was transparent, homogeneous, colourless, of neutral pH, spreadable and stable at 4°C for at least 3 months. It was active against parasites in vitro and in vivo, reducing CL lesion size by 84%-100% with no detected parasites. No signs of irritation, CHS or changes in weight, food intake, urea or transaminase serum levels were observed after treatment. CONCLUSIONS: The topical 0.5% miltefosine gel formulation was efficacious and non-toxic when administered topically in NW-CL murine models. This miltefosine formulation could be an appropriate candidate for further development.

American tegumentary leishmaniasis in Brazil: a critical review of the current therapeutic approach with systemic meglumine antimoniate and short-term possibilities for an alternative treatment.

OBJECTIVES: Meglumine antimoniate (MA; Glucantime®), the 80-year-old first-line systemic treatment for all forms of American tegumentary leishmaniasis (ATL) caused by Leishmania (Viannia) braziliensis, Leishmania (Viannia) guyanensis and Leishmania (Leishmania) amazonensis, is highly toxic, presents adverse side-effects and may not attain clinical and parasitological cure. This critical review examines the necessity for intramuscular/intravenous administration of MA, the alternatives to this approach, and the possibilities of developing affordable, accessible and non-toxic drugs or new delivery methods. METHOD: PubMed searches were performed using the terms 'cutaneous leishmaniasis' or 'American tegumentary leishmaniasis' in combination with 'meglumine antimoniate' or 'N-methyl glucamine' or 'drug repositioning' or 'nanotechnology'. Searches covered a period of 20 years of peer reviewed journals and technical bulletins. We explored the mode of action, pharmacokinetics, toxicity and efficacy of MA, evaluated the progress of ATL therapy in Brazil, and examined the potential of drug repositioning and nanotechnology in accelerating the introduction and/or optimisation of an alternative treatment. RESULTS: The evidence suggests that ATL therapy will continue to rely on systemic MA in the foreseeable future even though an intralesional subcutaneous route has evolved over the last 10 years. The chances of developing a novel drug for ATL or a new mode of delivery of MA are low. While MA nanocarriers afford a promising approach, this technology is still in its infancy. A more immediate solution would be the production of a bioequivalent of miltefosine, an efficacious oral agent no longer protected by patent. CONCLUSION: Development of a contemporary treatment requires governmental commitment in bringing together private and public sectors.

OBJECTIFS: L'antimoniate de méglumine (AM; Glucantime®), le traitement systémique de première intention vieux de 80 ans pour toutes les formes de la leishmaniose tégumentaire américaine (LTA) causée par Leishmania (Viannia) braziliensis, L. (V.) guyanensis et L. (Leishmania) amazonensis, est hautement toxique, présente des effets secondaires indésirables et peut ne pas aboutir à une guérison clinique et parasitologique. Cette analyse critique examine la nécessité d'une administration intramusculaire/intraveineuse d'AM, les alternatives à cette approche et les possibilités de développement de médicaments abordables, accessibles et non toxiques ou de nouvelles méthodes d'administration. MÉTHODE: Des recherches sur PubMed ont été effectuées en utilisant les termes «leishmaniose cutanée¼ ou «leishmaniose tégumentaire américaine¼ en combinaison avec «antimoniate de méglumine ¼ ou «N-méthyl glucamine¼ ou «repositionnement de médicament¼ ou «nanotechnologie¼. Les recherches ont porté sur une période de 20 ans d'articles revue par des pairs et de bulletins techniques. Nous avons exploré le mode d'action, la pharmacocinétique, la toxicité et l'efficacité de l'AM, évalué les progrès du traitement de la LTA au Brésil et examiné le potentiel du repositionnement de médicaments et de la nanotechnologie pour accélérer l'introduction et/ou l'optimisation d'un traitement alternatif. RÉSULTATS: Les données suggèrent que le traitement de la LTA continuera à s'appuyer sur l'AM systémique dans un avenir proche, même si une voie sous-cutanée intralésionnelle a évolué au cours des 10 dernières années. Les chances de développer un nouveau médicament pour la LTA ou un nouveau mode d'administration d'AM sont faibles. Alors que les nanocarriers d'AM offrent une approche prometteuse, cette technologie en est encore à ses balbutiements. Une solution plus immédiate consisterait à produire un bioéquivalent de miltéfosine, un agent oral efficace, qui n'est plus protégé par un brevet. CONCLUSION: Le développement d'un traitement contemporain nécessite un engagement gouvernemental pour réunir les secteurs privés et publiques.

Transvascular Delivery of Hydrophobically Modified siRNAs: Gene Silencing in the Rat Brain upon Disruption of the Blood-Brain Barrier.

Effective transvascular delivery of therapeutic oligonucleotides to the brain presents a major hurdle to the development of gene silencing technologies for treatment of genetically defined neurological disorders. Distribution to the brain after systemic administrations is hampered by the low permeability of the blood-brain barrier (BBB) and the rapid clearance kinetics of these drugs from the blood. Here we show that transient osmotic disruption of the BBB enables transvascular delivery of hydrophobically modified small interfering RNA (hsiRNA) to the rat brain. Intracarotid administration of 25% mannitol and hsiRNA conjugated to phosphocholine-docosahexanoic acid (PC-DHA) resulted in broad ipsilateral distribution of PC-DHA-hsiRNAs in the brain. PC-DHA conjugation enables hsiRNA retention in the parenchyma proximal to the brain vasculature and enabled active internalization by neurons and astrocytes. Moreover, transvascular delivery of PC-DHA-hsiRNAs effected Htt mRNA silencing in the striatum (55%), hippocampus (51%), somatosensory cortex (52%), motor cortex (37%), and thalamus (33%) 1 week after administration. Aside from mild gliosis induced by osmotic disruption of the BBB, transvascular delivery of PC-DHA-hsiRNAs was not associated with neurotoxicity. Together, these findings provide proof-of-concept that temporary disruption of the BBB is an effective strategy for the delivery of therapeutic oligonucleotides to the brain.

Combination oral therapy against Leishmania amazonensis infection in BALB/c mice using nanoassemblies made from amphiphilic antimony(V) complex incorporating miltefosine.

Clinically available drugs for mucocutaneous and cutaneous leishmaniases (CL) include mainly pentavalent antimony (Sb(V)) complexes, liposomal amphotericin B, and miltefosine (HePC). However, they present at least one of the following limitations: long-term parenteral administration through repeated doses, severe side effects, drug resistance, and high cost. HePC is the only oral drug available, but the appearance of resistance has resulted in changes of its use from monotherapy to combination therapy. Amphiphilic Sb(V) complexes, such as SbL8 obtained from reaction of Sb(V) with N-octanoyl-N-methylglucamide, were recently found to be orally active against experimental CL. The property of SbL8 to self-assemble in aqueous solution, forming nanostructures, led us to investigate the incorporation of HePC into SbL8 nanoassemblies and the therapeutic efficacy of SbL8/HePC nanoformulation by oral route in a murine model of CL. HePC incorporation into the SbL8 nanosystem was evidenced by using a fluorescent analog of HePC. The antileishmanial activity of SbL8/HePC nanoassemblies was evaluated after daily oral administration for 30 days in Leishmania amazonensis-infected BALB/c mice, in comparison with monotherapies (SbL8 or HePC) and saline control. All the treatments resulted in significant reduction in the lesion size growth, when compared with control. Strikingly, only SbL8/HePC nanoassemblies promoted a significant decrease of the parasite burden in the lesion. This work establishes the therapeutic benefit of SbL8/HePC association by oral route in a CL model and constitutes an important step towards the development of new orally active drug combination.

Inhibition of denture plaque deposition on complete dentures by 2-methacryloyloxyethyl phosphorylcholine polymer coating: A clinical study.

STATEMENT OF PROBLEM: Denture plaque-associated infections are regarded as a source of serious dental and medical complications in the elderly population. Methods of managing this problem are needed. PURPOSE: The purpose of this clinical study was to evaluate the effects of treatment with a 2-methacryloyloxyethyl phosphorylcholine polymer, PMBPAz, on plaque deposition in complete dentures. MATERIAL AND METHODS: The study protocol was approved by the Ethics Committee of Showa University (#2013-013). Eleven individuals with maxillary complete dentures participated in this study. Their dentures were treated with PMBPAz, and the amount of denture plaque accumulation was evaluated by staining the denture surfaces with methylene blue after 2 weeks of denture usage. The same procedures were repeated to evaluate the original denture surfaces as a control. The image of the stained denture surface was captured using a digital camera, and the percentage of stained area, quantified as a pixel-based density, of the whole denture area (percentage of plaque index) was calculated for the mucosal and polished surfaces. To quantify the biofilm on the dentures, denture plaque biofilm was detached by ultrasonic vibration, resuspended in diluent, and measured with a microplate reader at an optical density of 620 nm. The effects of PMBPAz treatment on these variables were statistically analyzed with ANOVA (α=.05). RESULTS: The mean ±SD percentage of plaque index was 40.7% ±19.9% on the mucosal surfaces and 28.0% ±16.8% on the polished surfaces of the control denture. The mean percentage of plaque index of PMBPAz-treated dentures significantly decreased to 17.4%% ±12.0% on the mucosal surfaces (P<.001) and 15.0% ±9.9% on the polished surfaces (P<.05). The quantification of plaque deposition agreed with the results of these image analyses. CONCLUSIONS: These results demonstrated the effectiveness of the treatment with the PMBPAz to inhibit the bacterial plaque deposition on complete dentures.

Perifosine enhances bevacizumab-induced apoptosis and therapeutic efficacy by targeting PI3K/AKT pathway in a glioblastoma heterotopic model.

Bevacizumab (BVZ) as an antiangiogenesis therapy leads to a transient therapeutic efficacy in high-grade glioma. However, the proapoptotic potential of BVZ has not been well elucidated, yet. There is also a tumor resistance to BVZ that is linked to post-treatment metalloproteinases and AKT activities. Herein, the association between therapeutic efficacy and putative proapoptotic activity of low-dose BVZ either alone or in combination with a specific inhibitor of AKT called perifosine (PRF), in a glioma model was investigated. BALB/c mice bearing C6 glioma tumor were treated with BVZ and PRF either alone or combined for 13 days (n = 11/group). At the end of treatments, apoptosis, proliferation and vascular density, in the xenografts (3/group) were detected by TUNEL staining, Ki67 and CD31 markers, respectively. Relative levels of cleaved-caspase3, phospho-AKT (Ser473) and matrix metalloproteinase2 (MMP2) were measured using western blotting. PRF and BVZ separately slowed down tumor growth along with the cell apoptosis induction associated with a profound increase in caspase3 activity through an AKT inhibition-related pathway for PRF but not BVZ. Unlike PRF, BVZ significantly increased the intratumor MMP2 and phospho-AKT (Ser473) levels coupled with the slight antiproliferative and significant antivascular effects. Co-administration of PRF and BVZ versus monotherapies potentiated the proapoptotic effects and reversed the BVZ-induced upregulation of phospho-AKT (Ser473) and MMP2 levels in C6 xenografts, leading to the optimal antiproliferative activity and tumor growth regression and longer survival. In conclusion, BVZ plus PRF renders a paramount proapoptotic effect, leading to a major therapeutic efficacy and might be a new substitute for GBM therapy in the clinic.

Plasma and cerebrospinal fluid pharmacokinetics of select chemotherapeutic agents following intranasal delivery in a non-human primate model.

The blood-brain barrier (BBB) limits entry of most chemotherapeutic agents into the CNS, resulting in inadequate exposure within CNS tumor tissue. Intranasal administration is a proposed means of delivery that can bypass the BBB, potentially resulting in more effective chemotherapeutic exposure at the tumor site. The objective of this study was to evaluate the feasibility and pharmacokinetics (plasma and CSF) of intranasal delivery using select chemotherapeutic agents in a non-human primate (NHP) model. Three chemotherapeutic agents with known differences in CNS penetration were selected for intranasal administration in a NHP model to determine proof of principle of CNS delivery, assess tolerability and feasibility, and to evaluate whether certain drug characteristics were associated with increased CNS exposure. Intravenous (IV) temozolomide (TMZ), oral (PO) valproic acid, and PO perifosine were administered to adult male rhesus macaques. The animals received a single dose of each agent systemically and intranasally in separate experiments, with each animal acting as his own control. The dose of the agents administered systemically was the human equivalent of a clinically appropriate dose, while the intranasal dose was the maximum achievable dose based on the volume limitation of 1 mL. Multiple serial paired plasma and CSF samples were collected and quantified using a validated uHPLC/tandem mass spectrometry assay after each drug administration. Pharmacokinetic parameters were estimated using non-compartmental analysis. CSF penetration was calculated from the ratio of areas under the concentration-time curves for CSF and plasma (AUCCSF:plasma). Intranasal administration was feasible and tolerable for all agents with no significant toxicities observed. For TMZ, the degrees of CSF drug penetration after intranasal and IV administration were 36 (32-57) and 22 (20-41)%, respectively. Although maximum TMZ drug concentration in the CSF (Cmax) was lower after intranasal delivery compared to IV administration due to the lower dose administered, clinically significant exposure was achieved in the CSF after intranasal administration with the lower doses. This was associated with lower systemic exposure, suggesting increased efficiency and potentially lower toxicities of TMZ after intranasal delivery. For valproic acid and perifosine, CSF penetration after intranasal delivery was similar to systemic administration. Although this study demonstrates feasibility and safety of intranasal drug administration, further agent-specific studies are necessary to optimize agent selection and dosing to achieve clinically-relevant CSF exposures.

A phase I study of perifosine with temsirolimus for recurrent pediatric solid tumors.

BACKGROUND: The PI3K/AKT/mTOR pathway is aberrantly activated in many pediatric solid tumors including gliomas and medulloblastomas. Preclinical data in a pediatric glioma model demonstrated that the combination of perifosine (AKT inhibitor) and temsirolimus (mTOR inhibitor) is more potent at inhibiting the axis than either agent alone. We conducted this study to assess pharmacokinetics and identify the maximum tolerated dose for the combination. PROCEDURE: We performed a standard 3+3 phase I, open-label, dose-escalation study in patients with recurrent/refractory pediatric solid tumors. Four dose levels of perifosine (25-75 mg/m2 /day) and temsirolimus (25-75 mg/m2 IV weekly) were investigated. RESULTS: Twenty-three patients (median age 8.5 years) with brain tumors (diffuse intrinsic pontine glioma [DIPG] n = 8, high-grade glioma n = 6, medulloblastoma n = 2, ependymoma n = 1), neuroblastoma (n = 4), or rhabdomyosarcoma (n = 2) were treated. The combination was generally well tolerated and no dose-limiting toxicity was encountered. The most common grade 3 or 4 toxicities (at least possibly related) were thrombocytopenia (38.1%), neutropenia (23.8%), lymphopenia (23.8%), and hypercholesterolemia (19.0%). Pharmacokinetic findings for temsirolimus were similar to those observed in the temsirolimus single-agent phase II pediatric study and pharmacokinetic findings for perifosine were similar to those in adults. Stable disease was seen in 9 of 11 subjects with DIPG or high-grade glioma; no partial or complete responses were achieved. CONCLUSIONS: The combination of these AKT and mTOR inhibitors was safe and feasible in patients with recurrent/refractory pediatric solid tumors.

Dendritic cell-targeting DNA-based nasal adjuvants for protective mucosal immunity to Streptococcus pneumoniae.

To develop safe vaccines for inducing mucosal immunity to major pulmonary bacterial infections, appropriate vaccine antigens (Ags), delivery systems and nontoxic molecular adjuvants must be considered. Such vaccine constructs can induce Ag-specific immune responses that protect against mucosal infections. In particular, it has been shown that simply mixing the adjuvant with the bacterial Ag is a relatively easy means of constructing adjuvant-based mucosal vaccine preparations; the resulting vaccines can elicit protective immunity. DNA-based nasal adjuvants targeting mucosal DCs have been studied in order to induce Ag-specific mucosal and systemic immune responses that provide essential protection against microbial pathogens that invade mucosal surfaces. In this review, initially a plasmid encoding the cDNA of Flt3 ligand (pFL), a molecule that is a growth factor for DCs, as an effective adjuvant for mucosal immunity to pneumococcal infections, is introduced. Next, the potential of adding unmethylated CpG oligodeoxynucleotide and pFL together with a pneumococcal Ag to induce protection from pneumococcal infections is discussed. Pneumococcal surface protein A has been used as vaccine for restoring mucosal immunity in older persons. Further, our nasal pFL adjuvant system with phosphorylcholine-keyhole limpet hemocyanin (PC-KLH) has also been used in pneumococcal vaccine development to induce complete protection from nasal carriage by Streptococcus pneumoniae. Finally, the possibility that anti-PC antibodies induced by nasal delivery of pFL plus PC-KLH may play a protective role in prevention of atherogenesis and thus block subsequent development of cardiovascular disease is discussed.

Experience with miltefosine for persistent or relapsing visceral leishmaniasis in solid organ transplant recipients: A case series from Spain.

The incidence of visceral leishmaniasis (VL) after solid organ transplantation (SOT) is increasing. The optimal therapy for post-transplant VL remains unclear, as relapses after liposomal amphotericin B (L-AmB) are common. Miltefosine has been shown to be effective for treating VL in immunocompetent patients, although data in the specific population of SOT recipients are lacking. In the setting of an outbreak of leishmaniasis occurring in Southwest Madrid, we reviewed our experience in 6 SOT recipients with persistent or relapsing VL who received a 28-day course of miltefosine (2.5 mg/kg/day) as salvage therapy. All patients had been treated previously with L-AmB as first-line therapy. The incident episode of VL occurred at a median of 14 months after transplantation. Two patients experienced persistent infection and the remaining 4 had a relapse after a median interval of 168 days since the completion of the course of L-AmB. All the patients had an apparent initial clinical improvement with miltefosine. However, VL relapsed in 3 of them (after a median interval of 46 days), which required retreatment with L-AmB-based regimens. Miltefosine therapy was followed by a prolonged secondary prophylaxis with L-AmB in the only 2 cases with sustained clinical response and ongoing immunosuppression. No adverse effects associated with miltefosine were observed. Albeit limited, our experience suggests that miltefosine monotherapy likely has a limited utility to obtain a long-lasting clinical response in complicated (persistent or relapsing) forms of post-transplant VL, although its role in association with L-AmB-based secondary prophylaxis may merit further investigation.

Platelet-activating factor receptor contributes to antileishmanial function of miltefosine.

Miltefosine [hexadecylphosphocholine (HPC)] is the only orally bioavailable drug for the disease visceral leishmaniasis, which is caused by the protozoan parasite Leishmania donovani. Although miltefosine has direct leishmanicidal effects, evidence is mounting for its immune system-dependent effects. The mechanism of such indirect antileishmanial effects of miltefosine remains to be discovered. As platelet-activating factor and HPC share structural semblances and both induce killing of intracellular Leishmania, we surmised that platelet-activating factor (PAF) receptor had a significant role in the antileishmanial function of miltefosine. The proposition was supported by molecular dynamic simulation of HPC docking into PAF receptor and by comparison of its leishmanicidal function on PAF receptor-deficient macrophages and mice under HPC treatment. We observed that compared with wild-type macrophages, the PAF receptor-deficient macrophages showed 1) reduced binding of a fluorescent analog of HPC, 2) decreased TNF-α production, and 3) lower miltefosine-induced killing of L. donovani. Miltefosine exhibited significantly compromised leishmanicidal function in PAF receptor-deficient mice. An anti-PAF receptor Ab led to a significant decrease in miltefosine-induced intracellular Leishmania killing and IFN-γ production in a macrophage-T cell coculture system. These results indicate significant roles for PAF receptor in the leishmanicidal activity of HPC. The findings open new avenues for a more rational understanding of the mechanism of action of this drug as well as for improved therapeutic strategies.