A New Perspective for the Treatment of Alzheimer's Disease: Exosome-like Liposomes to Deliver Natural Compounds and RNA Therapies.

With the increment of the aging population in recent years, neurodegenerative diseases exert a major global disease burden, essentially as a result of the lack of treatments that stop the disease progression. Alzheimer's Disease (AD) is an example of a neurodegenerative disease that affects millions of people globally, with no effective treatment. Natural compounds have emerged as a viable therapy to fill a huge gap in AD management, and in recent years, mostly fueled by the COVID-19 pandemic, RNA-based therapeutics have become a hot topic in the treatment of several diseases. Treatments of AD face significant limitations due to the complex and interconnected pathways that lead to their hallmarks and also due to the necessity to cross the blood-brain barrier. Nanotechnology has contributed to surpassing this bottleneck in the treatment of AD by promoting safe and enhanced drug delivery to the brain. In particular, exosome-like nanoparticles, a hybrid delivery system combining exosomes and liposomes' advantageous features, are demonstrating great potential in the treatment of central nervous system diseases.

Aerobic and resistance exercise in heart failure inpatients: a scoping review.

Exercise performance is an essential tool for managing heart failure. Although the benefits of exercise are well documented for people with chronic and stable heart failure, there is still no consensus on their prescription in patients hospitalized with acute heart failure undergoing clinical stabilization. The aim of this study is to identify the literature on exercise programs encompassing the components of aerobic and resistance training for hospitalized patients admitted for acute heart failure. A scoping review was conducted according to the proposed methodology of the Joanna Briggs Institute. Studies with adults over 18 years old, hospitalized, and diagnosed with acute heart failure who participated in aerobic and resistance exercise training programs during their hospital stay were included. Three studies met the inclusion criteria. One was a retrospective, observational analytical cohort study, in which the main outcome of the exercise program was improvement in the previous disabilities of the participants. The other two were multicenter randomized controlled studies that showed greater improvement in physical function, functional capacity, depression, quality of life, and frailty status in the intervention groups. The exercise prescriptions differed according to the principles of the exercise prescription-frequency of exercise, intensity of exercise, exercise time (duration), type (mode), exercise volume, and progression. It is too early to make recommendations based on evidence of the type structure of an exercise program with aerobic and strength-training components in this population. However, in the exercise programs of the reviewed studies, the predominance of light to moderate intensity and the importance of progressively increase the frequency and duration of the training sessions were demonstrated, with bicycle ergometers and walking being the most common types of aerobic exercises. It is recommended that investment and research in this area should continue with more methodologically robust studies.

pH-sensitive nanoliposomes for passive and CXCR-4-mediated marine yessotoxin delivery for cancer therapy.

Background: Yessotoxin (YTX), a marine-derived drug, was encapsulated in PEGylated pH-sensitive nanoliposomes, covalently functionalized (strategy I) with SDF-1α and by nonspecific adsorption (strategy II), to actively target chemokine receptor CXCR-4. Methods: Cytotoxicity to normal human epithelial cells (HK-2) and prostate (PC-3) and breast (MCF-7) adenocarcinoma models, with different expression levels of CXCR-4, were tested. Results: Strategy II exerted the highest cytotoxicity toward cancer cells while protecting normal epithelia. Acid pH-induced fusion of nanoliposomes seemed to serve as a primary route of entry into MCF-7 cells but PC-3 data support an endocytic pathway for their internalization. Conclusion: This work describes an innovative hallmark in the current marine drug clinical pipeline, as the developed nanoliposomes are promising candidates in the design of groundbreaking marine flora-derived anticancer nanoagents.

The effects of early rehabilitation on functional exercise tolerance in decompensated heart failure patients: Results of a multicenter randomized controlled trial (ERIC-HF study).

OBJECTIVE: To analyze (1) the effect of an aerobic training program on functional exercise tolerance in decompensated heart failure (DHF) patients; (2) to assess the effects of an aerobic training program on functional independence; and (3) dyspnea during activities of daily living. DESIGN: A randomized controlled clinical trial with follow-up at discharge. SETTINGS: Eight hospitals. Recruitment took place between 9/ 2017 and 3/2019. GROUP ASSIGNMENTS: Patients with DHF who were admitted to the hospital, were randomly assigned to usual rehabilitation care guideline recommended (control group) or aerobic training program (exercise group). MAIN OUTCOME: Functional exercise tolerance was measured with a 6-min walking test at discharge. RESULTS: In total 257 patients with DHF were included, with a mean age of 67 ± 11 years, 84% (n = 205) had a reduced ejection fraction and the hospital stay was 16 ± 10 days. At discharge, patients in the intervention group walked further compared to the control group (278 ± 117m vs 219 ± 115m, p < 0.01) and this difference stayed significant after correcting for confounders (p < 0.01). A significant difference was found favoring the exercise group in functional independence (96 ± 7 vs 93 ± 12, p = 0.02) and dyspnea associated to ADL (13 ± 5 vs 17 ± 7, p < 0.01) and these differences persisted after correcting for baseline values and confounders (functional independence p < 0.01; dyspnea associated with ADL p = 0.02). CONCLUSION: The ERIC-HF program is safe, feasible, and effective in increasing functional exercise tolerance and functional independence in hospitalized patients admitted due to DHF.

Novel concept of exosome-like liposomes for the treatment of Alzheimer's disease.

Exosomes are cell-derived vesicles that act as carriers for proteins and nucleic acids, with therapeutic potential and high biocompatibility. We propose a new concept of exosome-like liposomes for controlled delivery. The goal of this work was to develop a new type of liposomes with a unique mixture of phospholipids, similar to naturally occurring exosomes but overcoming their limitations of heterogeneity and low productivity, for therapeutic delivery of bioactive compounds. Curcumin was chosen as model compound, as it is a phytochemical molecule known to have antioxidant and anti-inflammatory properties, which can protect the brain against oxidative stress and reduce ß-amyloid accumulation, major hallmarks of Alzheimer's disease (AD). These new liposomes can efficiently encapsulate hydrophobic curcumin, yielding particles with a size smaller than 200 nm, and a polydispersity index lower than 0.20, which make them ideal for crossing the blood-brain barrier. These particles have a long shelf life, being stable up to 6 months. The curcumin encapsulation efficiency was higher than 85% (up to approximately 94%). Curcumin-loaded liposomes were not cytotoxic (up to 20 µM curcumin, and 200 µM of exo-liposomes), and significantly reduced oxidative stress induced in SH-SY5Y neuronal cells, indicating their potential for neuroprotection. They also do not show any toxicity and are internalized in zebrafish embryos, concentrating in lipid enriched areas, as the brain and the yolk sac. Such innovative carriers are a new effective approach to deliver drugs into the brain, as these are stable, protect the cargo and are uptaken by neuronal cells. Upon internalization, liposomes release the therapeutic biomolecules, resulting in successful neuroprotection, being a positive alternative strategy for AD therapy.

Self-Care in Heart Failure Inpatients: What Is the Role of Gender and Pathophysiological Characteristics? A Cross-Sectional Multicentre Study.

Heart failure is often characterised by low exercise capacity and a great impairment of performance in the activities of daily living. The correct management of the disease can prevent the worsening of symptoms and promote a better quality of life. The aims of this study are to understand the relationship of gender and pathophysiological characteristics with self-care behaviour and to evaluate the self-care behaviour in a sample of Portuguese heart failure inpatients, using the Self-Care of Heart Failure Index (SCHFI). A cross-sectional multicentre study enrolling 225 heart failure inpatients from eight hospitals from Portugal was performed. At admission, each patient's functional capacity was evaluated as well as their self-care behaviour, using the SCHFI Portuguese v6.2. A comparison between self-care behaviour with gender was performed. The patients' mean age was 68.4 ± 10.7 years old, 68% were male and 82.3% had reduced ejection fraction. A mean value of 47.9, 35.6 and 38.8 points was found in the SCHFI score of the sections self-care maintenance, self-care management and self-care confidence, respectively. Heart failure inpatients present inadequate levels of self-care behaviour. The results do not suggest a relationship between gender and pathophysiological characteristics with self-care behaviour.

Early rehabilitation in cardiology - heart failure: The ERIC-HF protocol, a novel intervention to decompensated heart failure patients rehabilitation.

BACKGROUND: Decompensated heart failure patients are characterised by functional dependence and low exercise tolerance. Aerobic exercise can improve symptoms, functional capacity and an increase in exercise tolerance. However, the benefits of early rehabilitation have not yet been validated. OBJECTIVE: To evaluate the safety and feasibility of an aerobic exercise training programme in functional capacity of decompensated heart failure patients. METHODOLOGY: A single centre, parallel, randomised controlled, open label trial, with 100 patients. The training group (TG, n=50) performed the training protocol and the control group (CG, n=50) performed the usual rehabilitation procedures. The London chest activity of daily living (LCADL) scale, the Barthel index (BI) and the 6 minute walking test (6MWT) at discharge were used to evaluate the efficacy of the protocol. Safety was measured by the existence of adverse events. RESULTS: The mean age of the patients was 70 years, 20% were New York Heart Association (NYHA) class IV and 80% NYHA class III at admission. The major heart failure aetiology was ischaemic (35 patients) and valvular disease (25 patients). There were no significant differences between groups at baseline in terms of sociodemographic or pathophysiological characteristics. There was a statistically significant difference of 54.2 meters for the training group (P=0.026) in the 6MWT and at LCADL 12 versus 16 (P=0.003), but the BI did not: 96 versus 92 (P=0.072). No major adverse events occurred. CONCLUSIONS: The training protocol demonstrated safety and efficacy, promoting functional capacity. This study elucidated about the benefits of a systematised implementation of physical exercise during the patient's clinical stabilisation phase, which had not yet been demonstrated.Trial registration: Clinicaltrials.gov NCT03838003, URL: https://clinicaltrials.gov/ct2/show/NCT03838003.

Exosome-like Nanoparticles: A New Type of Nanocarrier.

Nanoparticles are one of the most commonly used systems for imaging or therapeutic drug delivery. Exosomes are nanovesicular carriers that transport cargo for intercellular communication. These nanovesicles are linked to the pathology of some major diseases, in some cases with a central role in their progression. The use of these carriers to transport therapeutic drugs is a recent and promising approach to treat diseases such as cancer and Alzheimer disease. The physiological production of these structures is limited impairing its collection and subsequent purification. These drawbacks inspired the search for mimetic alternatives. The collection of exosome-like nanoparticles from plants can be a good alternative, since they are easier to extract and do not have the drawbacks of those produced in animal cells. Both natural and synthetic exosome-like nanoparticles, produced from serial extrusion of cells or by bottom up synthesis, are currently some of the most promising, biocompatible, high efficiency systems for drug delivery.

Impacto de um programa domiciliário de exercício físico na pessoa com doença cardíaca isquémica / Impact of a home-based physical exercise programme on people with ischaemic heart disease

A doença cardíaca isquémica é uma das mais importantes causas de diminuição da capacidade funcional e da qualidade de vida. A Reabilitação Cardíaca, com uma componente central de exercício físico, acompanhada pela consciencialização e ensino do doente sobre a doença cardíaca e fatores de risco cardiovascular, é uma ferramenta essencial para a recuperação do doente cardíaco, possibilitando a redução das limitações físicas e psicológicas, fomentando a adoção de um estilo de vida saudável. Metodologia: Foi realizado um estudo exploratório retrospetivo, com o objetivo principal de verificar o impacto de um programa domiciliário de exercício físico na capacidade funcional e qualidade de vida relacionada com a saúde, da pessoa com doença cardíaca isquémica do serviço de Cardiologia do Hospital de Santo António ­ Centro Hospitalar do Porto. A amostra é constituída por 13 doentes com doença cardíaca isquémica, que estiveram internados entre outubro e dezembro de 2016 e que não integraram a Fase II do programa de Reabilitação Cardíaca. Estes doentes foram submetidos a um programa domiciliário de exercício físico aeróbio durante três meses, com acompanhamento através de contactos telefónicos semanais. A colheita de dados foi efetuada em dois momentos distintos: à data da alta e três meses depois. Resultados: A amostra foi constituída por 84,6% de participantes do sexo masculino e a média de idades foi de 61,23±11,34 anos. A hipertensão arterial demonstrou ser o fator de risco cardiovascular mais prevalente (76,9%), seguido da hipercolesterolemia (69,2%). Em média, cada doente realizou 81±9,58 sessões de exercício físico no domicílio, sendo que o mínimo foram 59 e o máximo 93 sessões. No final do programa domiciliário, verificou-se um aumento no número médio de metros percorridos no Teste de Marcha de 6 minutos (339,77±61,34 vs. 533,77±117,39; p<0,05) e em seis dos oito domínios do formulário Abreviado da Avaliação de Saúde 36 - SF-36. Quanto aos contactos telefónicos, os doentes revelaram-se satisfeitos com este método de acompanhamento. Conclusão: No final do programa domiciliário de exercício físico aeróbio verificou-se uma melhoria na capacidade funcional e qualidade de vida relacionada com a saúde dos participantes do estudo. Contudo, serão necessários mais estudos, com amostras mais representativas e com mais recursos tecnológicos, de forma a possibilitar a análise e correlação de outras variáveis.

Coronary heart disease is one of the most important causes of decreased functional capacity and quality of life. Cardiac Rehabilitation, with a central component of exercise, accompanied by the patient's awareness and education about the heart disease and cardiovascular risk factors, is an essential tool for the recovery of the cardiac patient, allowing the reduction of physical and psychological limitations, promoting the adoption of a healthy lifestyle. Methods: A retrospective exploratory study was conducted, with the main objective of verifying the effects of a home-based exercise program on functional capacity and health-related quality of life, of the person diagnosed with coronary heart disease of the Cardiology department of Hospital de Santo António ­ Centro Hospitalar do Porto. The sample consists of 13 patients diagnosed with coronary heart disease, who were hospitalized between October and December 2016 and who didn't participate in Phase II of the Cardiac Rehabilitation program. These patients underwent a home-based aerobic exercise program for three months, with weekly follow-up via phone call. Data collection was performed at two different times: upon discharge and three months after. Results: The sample consisted of 84.6% of male participants and the average age was 61.23±11.34 years. Arterial hypertension proved to be the most prevalent cardiovascular risk factor (76.9%), followed by dyslipidemia (69.2%). On average, each patient performed 81±9,58 exercise training sessions at home, with the minimum of 59 and the maximum of 93 sessions. At the end of the home-based program, there was an increase in the average number of meters walked in the 6-minute Walk Test (339.77±61.34 vs. 533.77±117.39, p<0.05) and in six of the eight domains of the Medical Outcomes Study 36 ­ item short form health survey. As for telephone contacts, patients were satisfied with this method of follow-up. Conclusion: At the end of the home-based aerobic exercise program, there was an improvement in functional capacity and health-related quality of life of the participants of the study. However, more studies will be necessary, together with more representative samples and more technological resources, to allow the analysis and correlation of other variables.

Resin-bonded fixed dental prosthesis with a modified treatment surface in a zirconia framework: a case report.

Although resin-bonded fixed dental prostheses (RBFDPs) were developed almost 40 years ago, their implementation in clinical practice did not achieve success due to biomechanical failures of the restorative materials. Nowadays, the evolution of ceramic materials and bonding procedures has allowed for the revival of the dental prosthesis. Zirconia is the dental ceramic with the highest flexural strength under compression. However, there are still some concerns regarding the bonding strength of zirconia to enamel that require further research. In this article, through the presentation of three clinical cases, the authors show how modifying the surface of zirconia frameworks by applying a feldspathic veneering on the retainer's buccal surface allows for a bonding procedure to dental structures. The goal of this treatment method is to simultaneously improve structural strength, esthetic integration, and bonding optimization to enamel. In a 3-year prospective evaluation, this framework modification shows promising results, with a survival rate of 100% and no biological or mechanical complications.

Counter ions and constituents combination affect DODAX : MO nanocarriers toxicity in vitro and in vivo.

Liposomes have received extensive attention as nanocarriers for bioactive compounds due to their good biocompatibility, possibility of targeting and incorporation of hydrophilic and hydrophobic compounds. Although generally considered as safe, detailed knowledge of the effects induced in cells and tissues with which they interact is still underexplored. The aim of this study is to gain insight into the toxicity profile of dioctadecyldimethylammonium (DODAX) : monoolein(MO) liposomes (X is bromide or chloride), previously validated for gene therapy, by evaluating the effect of the counter ions Br- or Cl-, and of the cationic : neutral lipid molar fraction, both in vitro and in vivo. Effects on cellular metabolism and proliferation, plasma membrane integrity, oxidative stress, mitochondrial membrane potential dysfunction and ability to trigger apoptosis and necrosis were evaluated in a dose-/time-dependent manner in normal human skin fibroblasts. Also, newly fertilized zebrafish zygotes were exposed to liposomes, permitting a fast-track evaluation of the morphophysiological modifications. In vitro data showed that only very high doses of DODAX : MO induce apoptosis and necrosis, inhibit cell proliferation, and affect the metabolism and plasma membrane integrity of fibroblasts in a dose-/time-dependent manner. Furthermore, liposomes affected mitochondrial function, increasing ROS accumulation and disturbing mitochondrial membrane potential. DODAC-based liposomes were consistently more toxic when compared to DODAB-based formulations; furthermore, the inclusion of MO was found to reduce toxicity, in contrast to liposomes with cationic DODAX only, especially in DODAB : MO (1 : 2) nanocarriers. These results were corroborated, in a holistic approach, by cytotoxicity profiling in five additional human cell lines, and also with the zebrafish embryotoxicity testing, which constitutes a sensitive and informative tool and accurately extends cell-based assays.

Monoolein-based nanocarriers for enhanced folate receptor-mediated RNA delivery to cancer cells.

We report the development and characterization of a novel nanometric system for specific delivery of therapeutic siRNA for cancer treatment. This vector is based on a binary mixture of the cationic surfactant dioctadecyldimethylammonium chloride (DODAC) and the helper lipid monoolein (MO). These liposomes were previously validated by our research group as promising non-viral vectors for nucleic acid delivery. In this work, the DODAC:MO vesicles were for the first time functionalized with polyethylene glycol and PEG-folate conjugates to achieve both maximal stability in biological fluids and increase selectivity toward folate receptor α expressing cells. The produced DODAC:MO:PEG liposomes were highly effective in RNA complexation (close to 100%), and the resulting lipoplexes also demonstrated high stability in conditions simulating their administration by intravenous injection (physiological pH, high NaCl, heparin and fetal bovine serum concentrations). In addition, cell uptake of the PEG-folate-coated lipoplexes was significantly greater in folate receptor α positive breast cancer cells (39% for 25 µg/mL of lipid and 31% for 40 µg/mL) when compared with folate receptor α negative cells (31% for 25 µg/mL of lipid and 23% for 40 µg/mL) and to systems without PEG-folate (≈13% to 16% for all tested conditions), supporting their selectivity towards the receptor. Overall, the results support these systems as appealing vectors for selective delivery of siRNA to cancer cells by folate receptor α-mediated internalization, aiming at future therapeutic applications of interest.

Stealth monoolein-based nanocarriers for delivery of siRNA to cancer cells.

While the delivery of small interfering RNAs (siRNAs) is an attractive strategy to treat several clinical conditions, siRNA-nanocarriers' stability after intravenous administration is still a major obstacle for the development of RNA-interference based therapies. But, although the need for stability is well recognized, the notion that strong stabilization can decrease nanocarriers' efficiency is sometimes neglected. In this work we evaluated two stealth functionalization strategies to stabilize the previously validated dioctadecyldimethylammonium bromide (DODAB):monoolein (MO) siRNA-lipoplexes. The nanocarriers were pre- and post-pegylated, forming vectors with different stabilities in biological fluids. The stealth nanocarriers' behavior was tested under biological mimetic conditions, as the production of stable siRNA-lipoplexes is determinant to achieve efficient intravenous siRNA delivery to cancer cells. Upon incubation in human serum for 2h, by fluorescence Single Particle Tracking microscopy, PEG-coated lipoplexes were found to have better colloidal stability as they could maintain a relatively stable size. In addition, using fluorescence fluctuation spectroscopy, post-pegylation also proved to avoid siRNA dissociation from the nanocarriers in human serum. Concomitantly it was found that PEG-coated lipoplexes improved cellular uptake and transfection efficiency in H1299 cells, and had the ability to silence BCR-ABL, affecting the survival of K562 cells. Based on an efficient cellular internalization, good silencing effect, good siRNA retention and good colloidal stability in human serum, DODAB:MO (2:1) siRNA-lipoplexes coated with PEG-Cer are considered promising nanocarriers for further in vivo validation. STATEMENT OF SIGNIFICANCE: This work describes two stealth functionalization strategies for the stabilization of the previously validated dioctadecyldimethylammonium bromide (DODAB):monoolein (MO) siRNA-lipoplexes. These nanocarriers are capable of efficiently incorporating and delivering siRNA molecules to cells in order to silence genes whose expression is implicated in a pathological condition. The main objective was to functionalize these nanocarriers with a coating conferring protection to siRNA in blood without compromising its efficient delivery to cancer cells, validating the potential of DODAB:MO (2:1) siRNA-lipoplexes as therapeutic vectors. We show that the stealth strategy is determinant to achieve a stable and efficient nanocarrier, and that DODAB:MO mixtures have a very promising potential for systemic siRNA delivery to leukemic cells.

Can serum angiogenin be used to improve the diagnostic performance in prostate cancer screening?

Several biomarkers have been studied to avoid unnecessary biopsies resulting from suboptimal performance of prostate-specific antigen (PSA) testing. We aimed to assess the use of serum angiogenin as a prostate cancer diagnostic tool among candidates for biopsy. We selected 252 patients referred for ultrasound-guided transrectal prostate biopsy on the basis of an abnormal digital rectal examination and/or elevated total PSA. Serum angiogenin was quantitatively analyzed by solid-phase enzyme-linked immunosorbent assay. Results of the prostatic pathology assessment (cancer vs. noncancer) were defined by biopsy. The median serum angiogenin levels were significantly higher in patients with prostate cancer (median: 487,500 vs. 414,800 pg/ml, P=0.008). Among patients with baseline tPSA of 4.0 ng/ml or less, 37.5% had serum angiogenin less than 389,000 pg/ml (sensitivity: 88.9%; specificity: 45.2%), and the probability of having prostate cancer varied from 22.5% before testing to 6.7% among those with low angiogenin levels. When further restricting the analyses to a group of patients with even lower probability of having cancer, on the basis of tPSA and f/t PSA values, the evaluation of serum angiogenin did not contribute toward a meaningful variation in the post-test probability of cancer. In conclusion, serum angiogenin levels may be useful to distinguish between cancer and noncancer patients among the candidates for prostatic biopsy in regular clinical practice. Further investigation is needed among patients with low PSA levels and to understand the relation between this biomarker and the long-term survival of prostate cancer patients.

Penile corporoplasty with Yachia's technique for Peyronie's disease: Single center experience with 117 patients.

INTRODUCTION: Peyronie's disease is an acquired penile deformity with a variety of presentations, caused by the formation of fibrous plaques within the tunica albuginea, leading to bio-mechanical and vascular abnormalities. The objective is to investigate the 18 years outcome of patients with Peyronie's disease treated with penile corporoplasty (Yachia technique) in our department. MATERIALS AND METHODS: One hundred and seventeen patients underwent surgical treatment for PD between 1991 and 2009 and were retrospectively evaluated. We used the Levine and Lenting's algorithm for surgical treatment. Data was obtained from medical records, clinical evaluation, and telephone interview. Post-operative follow-up was at 6 weeks and 12 months. The mean time of follow-up was 14 months (12-19 months). MAIN OUTCOME MEASURES: Patient demographic, co-morbidities, erectile function, penile curvature, and surgical intervention were documented. The main outcome measures of this study are postoperative complications, surgical purpose, and patients and partner's satisfaction rates. RESULTS: Surgical aim was obtained in 106 patients (success rate of 94.6%). Complications occurred in 4.5% of patients, but most of these were mild. At 6 weeks, complete straightening of the penis was achieved in 57 patients (50.9%), and partial straightening which allow sexual intercourse in 49 patients (43.7%). Nine patients report gland hypoesthesia and almost all report subjective perception of penis shortening (0.5 cm to 5 cm). Twenty-two patients developed recurrent deformity at 12 months follow-up, with compromise of sexual intercourse in 7 patients. Patients' responses to our questionnaire showed that overall 88.4% of the patients and partners were satisfied with the surgical results. CONCLUSION: According to the results of this long-term, retrospective study, surgical correction, using the Yachia technique, is an excellent option for patients with functional impairment from their Peyronie's disease, especially.

A data encryption solution for mobile health apps in cooperation environments.

BACKGROUND: Mobile Health (mHealth) proposes health care delivering anytime and anywhere. It aims to answer several emerging problems in health services, including the increasing number of chronic diseases, high costs on national health services, and the need to provide direct access to health services, regardless of time and place. mHealth systems include the use of mobile devices and apps that interact with patients and caretakers. However, mobile devices present several constraints, such as processor, energy, and storage resource limitations. The constant mobility and often-required Internet connectivity also exposes and compromises the privacy and confidentiality of health information. OBJECTIVE: This paper presents a proposal, construction, performance evaluation, and validation of a data encryption solution for mobile health apps (DE4MHA), considering a novel and early-proposed cooperation strategy. The goal was to present a robust solution based on encryption algorithms that guarantee the best confidentiality, integrity, and authenticity of users health information. In this paper, we presented, explained, evaluated the performance, and discussed the cooperation mechanisms and the proposed encryption solution for mHealth apps. METHODS: First, we designed and deployed the DE4MHA. Then two studies were performed: (1) study and comparison of symmetric and asymmetric encryption/decryption algorithms in an mHealth app under a cooperation environment, and (2) performance evaluation of the DE4MHA. Its performance was evaluated through a prototype using an mHealth app for obesity prevention and cares, called SapoFit. We then conducted an evaluation study of the mHealth app with cooperation mechanisms and the DE4MHA using real users and a real cooperation scenario. In 5 days, 5 different groups of 7 students selected randomly agreed to use and experiment the SapoFit app using the 7 devices available for trials. RESULTS: There were 35 users of SapoFit that participated in this study. The performance evaluation of the app was done using 7 real mobile devices in 5 different days. The results showed that confidentiality and protection of the users' health information was guaranteed and SapoFit users were able to use the mHealth app with satisfactory quality. Results also showed that the app with the DE4MHA presented nearly the same results as the app without the DE4MHA. The performance evaluation results considered the probability that a request was successfully answered as a function of the number of uncooperative nodes in the network. The service delivery probability decreased with the increase of uncooperative mobile nodes. Using DE4MHA, it was observed that performance presented a slightly worse result. The service average was also slightly worse but practically insignificantly different than with DE4MHA, being considered negligible. CONCLUSIONS: This paper proposed a data encryption solution for mobile health apps, called DE4MHA. The data encryption algorithm DE4MHA with cooperation mechanisms in mobile health allow users to safely obtain health information with the data being carried securely. These security mechanisms did not deteriorate the overall network performance and the app, maintaining similar performance levels as without the encryption. More importantly, it offers a robust and reliable increase of privacy, confidentiality, integrity, and authenticity of their health information. Although it was experimented on a specific mHealth app, SapoFit, both DE4MHA and the cooperation strategy can be deployed in other mHealth apps.

A new mobile ubiquitous computing application to control obesity: SapoFit.

The objective of this work was the proposal, design, construction and validation of a mobile health system for dietetic monitoring and assessment, called SapoFit. This application may be personalized to keep a daily personal health record of an individual's food intake and daily exercise and to share this with a social network. The initiative is a partnership with SAPO - Portugal Telecom. SapoFit uses Web services architecture, a relatively new model for distributed computing and application integration. SapoFit runs on a range of mobile platforms, and it has been implemented successfully in a range of mobile devices and has been evaluated by over 100 users. Most users strongly agree that SapoFit has an attractive design, the environment is user-friendly and intuitive, and the navigation options are clear.