How an electronic prescription tool enables better prescription quality for patients

Objective: Medication-related errors in patients are among the leading causes of preventable health damage and harm worldwide. In the United States, these errors cause at least one death a day and damage approximately 1.3 million people annually. According to the World Health Organization, the global expenditure on medication-related errors is estimated to be U$ 42 billion per year. In Brazil, the rate of potential drug interactions varies between 28% and 63.6% for primary care patients. The prevalence of drug interactions has increased following an aging population, increased chronic conditions, combined use of different drugs, and increased prescription drugs per patient. Methods: The data used for this study were obtained through the database from Nexodata do Brasil S.A a private health technology company with an electronic prescription system and a data intelligence area. Results: 65,867 electronic prescriptions were evaluated during 2019. Of these, 4,828 prescriptions had an average of 2.5 interactions. These interactive prescriptions were generated by 197 different doctors, totaling 24.5 prescriptions with interaction per doctor over 12 months. A total of 12,005 interactions were identified, 15.6% classified as mild, 70.9% as moderate, and 13.5% as severe. Conclusion: By implementing an electronic prescription tool, a reduction of 32.9% in the number of prescriptions with drug interaction was observed.

Como uma ferramenta de prescrição eletrônica possibilita uma melhor qualidade na prescrição para os pacientes / How an electronic prescription tool enables better prescription quality for patients

Introdução: Os erros relacionados à medicação de pacientes estão entre as maiores causas de danos e prejuízos evitáveis à saúde em todo o mundo. Nos Estados Unidos, esses erros causam pelo menos uma morte por dia e causam danos a aproximadamente 1,3 milhão de pessoas anualmente. Segundo a Organização Mundial da Saúde, estima-se que o gasto global com erros relacionados à medicação seja de US$ 42 bilhões por ano. No Brasil, a taxa de interações medicamentosas potenciais varia entre 28% e 63,6% em pacientes de serviços de atenção primária. A prevalência de interações medicamentosas tem aumentado, seguindo o envelhecimento populacional, aumento de condições crônicas, uso combinado de diferentes medicamentos e aumento na quantidade de medicamentos prescritos. Métodos: Os dados utilizados para o presente estudo foram obtidos por meio da base de dados da Nexodata do Brasil S.A., que é uma empresa privada de tecnologia em saúde que possui um sistema de prescrição eletrônica e uma área de inteligência de dados. Resultados: Foram avaliadas 65.867 prescrições eletrônicas durante o ano de 2019; dessas, 4.828 prescrições apresentaram em média 2,5 interações. Essas prescrições com interação foram geradas por 197 médicos diferentes, totalizando um total de 24,5 receitas com interação por médico ao longo de 12 meses. Foi identificado um total de 12.005 interações, sendo 15,6% classificadas como leves, 70,9% como moderadas e 13,5% como graves. Conclusão: Por meio da implementação de uma ferramenta de prescrição eletrônica, foi observada uma redução de 32,9% na quantidade de receitas com interação medicamentosa.

Introduction: Medication-related errors in patients are among the leading causes of preventable health damage and harm worldwide. In the United States, these errors cause at least one death a day and damage approximately 1.3 million people annually. According to the World Health Organization, the global expenditure on medication-related errors is estimated to be U$ 42 billion per year. In Brazil, the rate of potential drug interactions varies between 28% and 63.6% in primary care patients. The prevalence of drug interactions has increased following an aging population, an increase in chronic conditions, combined use of different drugs and an increase in the amount of prescription drugs per patient. Methods: The data used for the present study were obtained through the database of Nexodata do Brasil S.A., which is a private health technology company that has an electronic prescription system and a data intelligence area. Results: 65,867 electronic prescriptions were evaluated during the year 2019, of these, 4,828 prescriptions had an average of 2.5 interactions. These interactive prescriptions were generated by 197 different doctors, totaling a total of 24.5 prescriptions with interaction per doctor over 12 months. A total of 12,005 interactions were identified, 15.6% of which were classified as mild, 70.9% as moderate and 13.5% as severe. Conclusion: Through the implementation of an electronic prescription tool, a reduction of 32.9% in the amount of prescriptions with drug interaction was observed.

Biomechanical and histological characterization of MPS I mice femurs.

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disorder characterized by alpha-L-iduronidase (IDUA) deficiency, an enzyme responsible for glycosaminoglycan degradation. Musculoskeletal impairment is an important component of the morbidity related to the disease, as it has a major impact on patients' quality of life. To understand how this disease affects bone structure, morphological, biomechanical and histological analyses of femurs from 3- and 6-month-old wild type (Idua +/+) and MPS I knockout mice (Idua -/-) were performed. Femurs from 3-month-old Idua -/- mice were found to be smaller and less resistant to fracture when compared to their age matched controls. In addition, at this age, the femurs presented important alterations in articular cartilage, trabecular bone architecture, and deposition of type I and III collagen. At 6 months of age, femurs from Idua -/- mice were more resistant to fracture than those from Idua +/+. Our results suggest that the abnormalities observed in bone matrix and articular cartilage in 3-month-old Idua -/- animals caused bone tissue to be less flexible and more likely to fracture, whereas in 6-month-old Idua -/- group the ability to withstand more load before fracturing than wild type animals is possibly due to changes in the bone matrix.

Aspectos do luto em familiares de mortos em decorrência da Covid-19 / Aspects of grief in family members of the dead as a result of Covid-19

A pandemia de Covid-19 tem gerado efeitos nocivos na saúde mental da população. Isso pode ser especialmente preocupante em pessoas que perderam familiares em decorrência da doença. Este estudo teve como objetivo compreender as particularidades do processo de luto diante da crise ocasionada pela Covid-19. Trata-se de uma pesquisa documental qualitativa que analisou reportagens publicadas entre março e abril de 2020 - período posterior a primeira morte registrada no Brasil - em cinco mídias de grande circulação. Os materiais foram selecionados por dois pesquisadores, e a análise de conteúdo foi realizada pelo método de Bardin. Cinco categorias de análise foram identificadas: Desafios de uma experiência nova e urgente, preconceito decorrente do contato com doentes, sentimentos, formas de enfrentamento e rituais funerários. Manifestações de revolta diante da minimização da doença por autoridades foram frequentes, bem como queixas relacionadas a organização do sistema de saúde, inexistência de fluxos e desinformação dos profissionais. Diante da disseminação de Fake News, foram observados relatos de hostilizações em redes sociais e o afastamento de pessoas conhecidas, gerando solidão. O medo de estar contaminado e de transmitir para outras pessoas também foi recorrente. Ainda, notou-se que a impossibilidade de acompanhar o familiar morto durante a internação e as limitações dos rituais foram associados a culpa e tristeza. É possível que a experiência do luto seja intensificada diante das peculiaridades que permeiam o processo de morte decorrente da Covid-19, sobretudo nos primeiros meses da pandemia. Tendo em vista que os efeitos na saúde mental da população podem ser mais duradouros do que a pandemia, é fundamental que investigações sejam realizadas e estratégias de suporte desenvolvidas.(AU)

The Covid-19 pandemic has had harmful effects on the populations mental health. This can be worrisome in people who have lost family members to Covid-19. This study aims to understand the particularities of the mourning process during the crisis caused by Covid-19. This is a qualitative documentary research that analyzed reports published between March and April 2020 - a period after the first recorded death in Brazil - in five large-circulation media. The materials were selected by two researchers, and content analysis was performed using the Bardin method. Five categories of analysis were identified: Challenges of a new and urgent experience, prejudice resulting from contact with patients, feelings, forms of confrontation and funeral rituals. Manifestations of anger at the authorities minimization of the disease were frequent, as well as complaints related to the organization of the health system, lack of flows and lack of information from professionals. Faced with the spread of Fake News, reports of harassment on social networks and the removal of known people were observed, generating loneliness. The fear of being contaminated and of transmitting it to other people was also recurrent. Furthermore, it was noted that the impossibility of accompanying the deceased family member during hospitalization and the limitations of the rituals were associated with guilt and sadness. It is possible that the experience of grief is intensified given the peculiarities that permeate the process of death resulting from Covid-19, especially in the first months of the pandemic. Considering that the effects on the populations mental health can be more lasting than the pandemic, it is essential that investigations are carried out and support strategies developed.(AU)

La pandemia de Covid-19 ha tenido efectos nocivos en la salud mental de la población. Esto puede ser preocupante en personas que han perdido a familiares a causa de Covid-19. Este estudio tuvo como objetivo comprender las particularidades del proceso de duelo ante la crisis provocada por el Covid-19. Se trata de uma investigación documental cualitativa que analizó informes publicados entre marzo y abril de 2020, un período posterior a la primera muerte registrada en Brasil. Los materiales fueron seleccionados y el análisis de contenido se realizó mediante el método Bardin. Se identificaron cinco categorías de análisis: Desafíos de una experiência nueva y urgente, Prejuicios derivados del contacto con los pacientes, Sentimientos, Formas de enfrentamiento y Ritos funerarios. Fueron frecuentes las manifestaciones de enfado por la minimización de la enfermedad por las autoridades, así como las quejas relacionadas con el sistema de salud, la falta de flujos y la falta de información por parte de los profesionales. Ante la difusión de Fake News, se observaron denuncias de hostigamiento en redes sociales y el alejamiento de personas conocidas, generando soledad. Además, se observó que la imposibilidad de acompañar al familiar fallecido durante la hospitalización y las limitaciones de los rituales se asociaron con la culpa y la tristeza. Es posible que la experiencia del duelo se intensifique dadas las peculiaridades que permean el proceso de muerte resultante del Covid-19, especialmente en los primeros meses de la pandemia. Considerando que los efectos en la salud mental de la población pueden ser más duraderos que la pandemia, es fundamental que se realicen investigaciones y se desarrollen estrategias de apoyo.(AU)

Case series of patients under biweekly treatment with laronidase: a report of a single center experience / Série de casos de pacientes em tratamento com laronidase quinzenal: relato da experiência de um centro

ABSTRACT Objective: To report the stabilization of urinary glycosaminoglicans (GAG) excretion and clinical improvements in patients with mucopolysaccharidosis type I (MPS I) under an alternative dose regimen of laronidase of 1.2 mg/kg every other week. Methods: We participated in a dose-optimization trial for laronidase in MPS-I patients using four alternative regimens: 0.58 mg/kg every week, 1.2 mg/kg every two weeks, 1.2 mg/kg every week and 1.8 mg/kg every other week (EOW). After the trial ended, the patients resumed the recommended dose and regimen of 0.58 mg/kg every week. Under this regimen, some patients presented difficulties in venous access and were unable to commute weekly to the treatment center. Therefore, we used an alternative regimen that consisted of 1.2 mg/kg EOW in eight patients. A retrospective study of medical records of MPS-I patients who underwent both enzyme replacement therapy (ERT) regimens, of 0.58 mg/kg every week and 1.2 mg/kg EOW, was done. Results: Patients remained clinically stable under the alternative regimen, did not present elevation of urinary GAG nor any adverse event. Conclusions: The switch of dose regimen to 1.2 mg/kg EOW of laronidase was safe, and did not cause any clinical worsening in patients who had been previously under standard dose ERT.

RESUMO Objetivo: Descrever a manutenção dos níveis de glicosaminoglicano (GAG) excretados na urina e da estabilização clínica em pacientes com mucopolissacaridose do tipo I (MPS I) com o uso da laronidase num regime de dose alternativo de 1,2 mg/kg a cada duas semanas. Método: Alguns pacientes do nosso serviço participaram de um estudo de otimização de dose da laronidase para o tratamento da MPS I no qual foram comparados quatro esquemas terapêuticos: 0,58 mg/kg/semana, 1,2 mg/kg a cada duas semanas, 1,2 mg/kg/semana e 1,8 mg/kg a cada duas semanas. Após o término do estudo, todos os pacientes passaram a receber a terapia de reposição enzimática (TRE) na dose padrão de bula, que é de 0,58 mg/kg/semana, e nesse regime alguns pais se queixaram da dificuldade em comparecer ao centro todas as semanas, além da dificuldade de se obter acesso para punção venosa. Com base nessas queixas, oito pacientes passaram a receber a TRE no regime alternativo de 1,2 mg/kg a cada duas semanas. Foi feito o estudo retrospectivo de dados de prontuário de pacientes com MPS I que fizeram TRE com laronidase nas doses 0,58 mg/kg/semana e 1,2 mg/kg a cada duas semanas. Resultados: Os pacientes mantiveram-se clinicamente estáveis, não apresentaram aumento dos níveis de GAG urinários nem eventos adversos durante o regime alternativo de dose. Conclusões: A mudança para o esquema de 1,2 mg/kg de laronidase a cada duas semanas foi segura e não acarretou piora clínica nos pacientes que já estavam em TRE na dose padrão.

CASE SERIES OF PATIENTS UNDER BIWEEKLY TREATMENT WITH LARONIDASE: A REPORT OF A SINGLE CENTER EXPERIENCE.

OBJECTIVE: To report the stabilization of urinary glycosaminoglicans (GAG) excretion and clinical improvements in patients with mucopolysaccharidosis type I (MPS I) under an alternative dose regimen of laronidase of 1.2 mg/kg every other week. METHODS: We participated in a dose-optimization trial for laronidase in MPS-I patients using four alternative regimens: 0.58 mg/kg every week, 1.2 mg/kg every two weeks, 1.2 mg/kg every week and 1.8 mg/kg every other week (EOW). After the trial ended, the patients resumed the recommended dose and regimen of 0.58 mg/kg every week. Under this regimen, some patients presented difficulties in venous access and were unable to commute weekly to the treatment center. Therefore, we used an alternative regimen that consisted of 1.2 mg/kg EOW in eight patients. A retrospective study of medical records of MPS-I patients who underwent both enzyme replacement therapy (ERT) regimens, of 0.58 mg/kg every week and 1.2 mg/kg EOW, was done. RESULTS: Patients remained clinically stable under the alternative regimen, did not present elevation of urinary GAG nor any adverse event.Conclusions: The switch of dose regimen to 1.2 mg/kg EOW of laronidase was safe, and did not cause any clinical worsening in patients who had been previously under standard dose ERT.

Lysosomal Acid Lipase Deficiency: Report of Five Cases across the Age Spectrum.

Lysosomal acid lipase (LAL) deficiency is an autosomal recessive lysosomal storage disorder caused by mutations in the LIPA gene that leads to premature organ damage and mortality. We present retrospective data from medical records of 5 Brazilian patients, showing the broad clinical spectrum of the disease.

The Underexploited Role of Non-Coding RNAs in Lysosomal Storage Diseases.

Non-coding RNAs (ncRNAs) are a functional class of RNA involved in the regulation of several cellular processes which may modulate disease onset, progression, and prognosis. Lysosomal storage diseases (LSD) are a group of rare disorders caused by mutations of genes encoding specific hydrolases or non-enzymatic proteins, characterized by a wide spectrum of manifestations. The alteration of ncRNA levels is well established in several human diseases such as cancer and auto-immune disorders; however, there is a lack of information focused on the role of ncRNA in rare diseases. Recent reports related to changes in ncRNA expression and its consequences on LSD physiopathology show us the importance to keep advancing in this field. This article will summarize recent findings and provide key points for further studies on LSD and ncRNA association.

Differential expression of microRNAs from miR-17 family in the cerebellum of mucopolysaccharidosis type I mice.

Mucopolysaccharidosis type I (MPS I) is caused by deficiency of α-l-iduronidase, involved in degradation of glycosaminoglycans. Clinical manifestations are widely variable and patients with severe phenotype present developmental delay and cognitive decline, among other systemic alterations. MPS I patients present secondary accumulation of gangliosides in neuronal cells, besides accumulation of undegraded glycosaminoglycans. Reduction of Neu1 expression has been previously observed in the cerebellum of MPS I mice; to be active, neuraminidase 1 forms the lysosomal multienzyme complex (LMC) with two other proteins, ß-galactosidase and protective protein/cathepsin A, involved in stepwise degradation of gangliosides in the lysosomes. In this study, we evaluated relative expression of LMC genes and six possible regulators of their expression, microRNAs (miRNAs) from miR-17 family, which are predicted to target at least two LMC components, in the cerebellum of MPS I mice by real-time PCR. Neu1 was significantly underexpressed in MPS I mice cerebellum, whereas expression of other LMC genes was similar to controls. miR-20b and miR-106b were differentially expressed in MPS I mice, suggesting that they may be involved in the reduction of Neu1 expression; miR-20b-5p was overexpressed while miR-20b-3p and miR-106b-5p were underexpressed. The ratio between miR-20b-3p and miR-20b-5p was also altered in cerebellum of MPS I mice. Confirmation of binding predictions and analysis of the direct role of these miRNAs in the regulation of Neu1 expression could bring important information regarding LMC function. Since miRNAs from miR-17 family are involved in regulation of diverse biological processes, our results also point to new pathogenic cascades to be investigated in MPS I.

α- L-iduronidase gene-based therapy using the phiC31 system to treat mucopolysaccharidose type I mice.

BACKGROUND: Mucopolysaccharidose type I (MPSI) is a lysosomal monogenic disease caused by mutations in the gene for α- L-iduronidase (IDUA). MPSI patients need a constant supply of IDUA to alleviate progression of the disease. IDUA gene transfer using integrative vectors might provide a definitive solution and support advancement to clinical trials, although studies have not yet been satisfactory. To achieve a stable IDUA gene expression in vivo, phiC31 was tested in the present study. METHODS: Several plasmid vectors were constructed and IDUA-/- mice were treated with cyclophosphamide and transfected with these vectors hydrodynamically via tail veins. IDUA expression was monitored over time. Treated and nontreated mice underwent an open-field test at age 8 months, and IDUA activity and glycosaminoglycan (GAG) content of tissues were evaluated. RESULTS: High levels of IDUA activity were detected initially (>1000 U/ml), although these levels decayed over time. The reinjection of vectors produced a similar profile of IDUA decay. Three out of six treated mice had IDUA activity in the livers, and also showed lower GAG content, reduced lysosomes and better locomotion. To investigate unsustained IDUA production, wild-type mice were submitted to the same gene therapy procedure, which generated a similar profile of IDUA decay. Anti-IDUA antibody was detected in the sera of these animals. In addition, we also found three methylated sites in the cytomegalovirus promoter region. CONCLUSIONS: phiC31-mediated gene therapy resulted in an important improvement in IDUA-/- mice, including locomotion, although the obstacles that need to be overcome to enable long-term gene therapy for MPSI are also noted.

Brazilian reference values for MPS II screening in dried blood spots--a fluorimetric assay.

OBJECTIVES: Mucopolysaccharidosis II (MPS II), or Hunter Syndrome, is a lysosomal storage disorder that is caused by the deficiency or absence of iduronate-2-sulfatase (IDS) enzyme; in this disease, early diagnosis is essential to provide higher life expectancy for patients. This study validates a fluorimetric assay that is used to assess IDS enzyme activity using dried blood spot (DBS) samples and presents the reference interval for the Brazilian population. DESIGN AND METHODS: Venous blood sample was collected in heparin tubes for leukocyte extraction and DBS preparation. IDS activity in the leukocytes was analyzed, and the results were considered the gold standard reference for the categorization of volunteers as positive or negative controls (PC and NC, respectively). IDS activity in the DBS was analyzed using an adapted version of the leukocyte assay. Statistical analyses were performed using a ROC curve to determine cutoff values and using a parametric Student's t test to compare values between genders. To verify that the assay yielded consistent results, a Bland-Altman plot was prepared. RESULTS: Leukocyte IDS activity values ranged between 2.71 and 17.36 nmol/mg protein/h in the NC group and between 0 and 0.11 nmol/mg protein/h in the PC group. Based on the DBS assay, activities ranged between 1.83 and 16.86 µmol/L blood/h in the NC group and between 0.58 and 4.32 µmol/L blood/h in the PC group. CONCLUSIONS: Reference values of IDS activity were determined in DBS with acceptable sensitivity and specificity. Therefore, the DBS assay described in this work may be a useful tool to screen MPS II patients in the Brazilian population.

Mesenchymal stem cells do not prevent antibody responses against human α-L-iduronidase when used to treat mucopolysaccharidosis type I.

Mucopolysaccharidosis type I (MPSI) is an autosomal recessive disease that leads to systemic lysosomal storage, which is caused by the absence of α-L-iduronidase (IDUA). Enzyme replacement therapy is recognized as the best therapeutic option for MPSI; however, high titers of anti-IDUA antibody have frequently been observed. Due to the immunosuppressant properties of MSC, we hypothesized that MSC modified with the IDUA gene would be able to produce IDUA for a long period of time. Sleeping Beauty transposon vectors were used to modify MSC because these are basically less-immunogenic plasmids. For cell transplantation, 4×10(6) MSC-KO-IDUA cells (MSC from KO mice modified with IDUA) were injected into the peritoneum of KO-mice three times over intervals of more than one month. The total IDUA activities from MSC-KO-IDUA before cell transplantation were 9.6, 120 and 179 U for the first, second and third injections, respectively. Only after the second cell transplantation, more than one unit of IDUA activity was detected in the blood of 3 mice for 2 days. After the third cell transplantation, a high titer of anti-IDUA antibody was detected in all of the treated mice. Anti-IDUA antibody response was also detected in C57Bl/6 mice treated with MSC-WT-IDUA. The antibody titers were high and comparable to mice that were immunized by electroporation. MSC-transplanted mice had high levels of TNF-alpha and infiltrates in the renal glomeruli. The spreading of the transplanted MSC into the peritoneum of other organs was confirmed after injection of 111In-labeled MSC. In conclusion, the antibody response against IDUA could not be avoided by MSC. On the contrary, these cells worked as an adjuvant that favored IDUA immunization. Therefore, the humoral immunosuppressant property of MSC is questionable and indicates the danger of using MSC as a source for the production of exogenous proteins to treat monogenic diseases.

Treatment of adult MPSI mouse brains with IDUA-expressing mesenchymal stem cells decreases GAG deposition and improves exploratory behavior.

BACKGROUND: Mucopolysaccharidosis type I (MPSI) is caused by a deficiency in alpha-L iduronidase (IDUA), which leads to lysosomal accumulation of the glycosaminoglycans (GAGs) dermatan and heparan sulfate. While the currently available therapies have good systemic effects, they only minimally affect the neurodegenerative process. Based on the neuroprotective and tissue regenerative properties of mesenchymal stem cells (MSCs), we hypothesized that the administration of MSCs transduced with a murine leukemia virus (MLV) vector expressing IDUA to IDUA KO mouse brains could reduce GAG deposition in the brain and, as a result, improve neurofunctionality, as measured by exploratory activity. METHODS: MSCs infected with an MLV vector encoding IDUA were injected into the left ventricle of the brain of 12- or 25-month-old IDUA KO mice. The behavior of the treated mice in the elevated plus maze and open field tests was observed for 1 to 2 months. Following these observations, the brains were removed for biochemical and histological analyses. RESULTS: After 1 or 2 months of observation, the presence of the transgene in the brain tissue of almost all of the treated mice was confirmed using PCR, and a significant reduction in GAG deposition was observed. This reduction was directly reflected in an improvement in exploratory activity in the open field and the elevated plus maze tests. Despite these behavioral improvements and the reduction in GAG deposition, IDUA activity was undetectable in these samples. Overall, these results indicate that while the initial level of IDUA was not sustainable for a month, it was enough to reduce and maintain low GAG deposition and improve the exploratory activity for months. CONCLUSIONS: These data show that gene therapy, via the direct injection of IDUA-expressing MSCs into the brain, is an effective way to treat neurodegeneration in MPSI mice.

Apoptosis status and proliferative activity in mucopolysaccharidosis type I mice tongue mucosa cells.

BACKGROUND: Mucopolysaccharidosis type I (MPS I) is caused by a deficiency of alfa-iduronidase (IDUA), which leads to intralysosomal accumulation of glysosaminoglycans. Evidences point secondary events like oxidative stress on lysosomal storage diseases including MPS I. Patients with MPS I present a wide range of oral clinical manifestations, including tongue hypertrophy, hypertrophyc alveolar process, and carious teeth. However, the mechanisms by which these alterations occur are still not fully understood. The aim of this study was to analyze the proliferative activity as well as apoptosis in tongue mucosa cells from murine model of MPS I. MATERIALS AND METHODS: Protein expression of apoptotic markers such as p53, bcl-2 and bax were evaluated in this setting. Ki-67 was used as a proliferative marker. All analyses were made by immunohistochemistry in tongue cells. Statistical analysis was perfomed by Kruskal-Wallis non-parametric test followed by the Dunn's test. P < 0.05 was considered for statistic significance. RESULTS: Histopathological analysis revealed no remarkable differences in tongue mucosa on MPS I mice when compared to control. By contrast, our results demonstrated that bcl-2 immunoexpression was decreased in mice tongue mucosa cells of MPS I mice. p53, bax and ki-67 immunoexpresssion did not show significant differences among controls and MPS I mice. CONCLUSION: Taken together, our results suggest that IDUA deficiency, which characterizes MPS I, may induce apoptosis in mice tongue cells as a result of bcl-2 down regulation.

Genomic instability in blood cells from murine model of mucopolysaccharidosis type I.

Mucopolysaccharidosis type I (MPS I) is caused by a deficiency of alfa-iduronidase (IDUA), which leads to intralysosomal accumulation of glycosaminoglycans. Some studies have revealed that oxidative stress plays an important role in MPS I. However, the mechanisms by which these alterations occur are still not fully understood. The aim of this study was to analyze genomic instability in blood cells from murine model of MPS I by single cell gel (comet) assay and micronucleus test. The results pointed out genetic damage in blood cells as depicted by the single cell gel (comet) assay results. By contrast, no increase of micronucleated cells were found in mouse blood cells when compared to negative control. Taken together, our results suggest that IDUA deficiency induces genomic damage in blood cells. Certainly, this finding offers new insights into the mechanisms underlying the relation between IDUA deficiency and clinical manifestations that can occur in MPS I patients.

Evidence of lysosomal membrane permeabilization in mucopolysaccharidosis type I: rupture of calcium and proton homeostasis.

Mucopolysaccharidosis type I (MPS I) is caused by a deficiency of alpha-iduronidase (IDUA), which leads to intralysosomal accumulation of glysosaminoglycans. Patients with MPS I present a wide range of clinical manifestations, but the mechanisms by which these alterations occur are still not fully understood. Genotype-phenotype correlations have not been well established for MPS I; hence, it is likely that secondary and tertiary alterations in cellular metabolism and signaling may contribute to the physiopathology of the disease. The aim of this study was to analyze Ca(2+) and H(+) homeostasis, lysosomal leakage of cysteine proteases, and apoptosis in a murine model of MPS I. After exposition to specific drugs, cells from Idua-/- mice were shown to release more Ca(2+) from the lysosomes and endoplasmic reticulum than Idua+/+ control mice, suggesting a higher intraorganelle store of this ion. A lower content of H(+) in the lysosomes and in the cytosol was found in cells from Idua-/- mice, suggesting an alteration of pH homeostasis. In addition, Idua-/- cells presented a higher activity of cysteine proteases in the cytosol and an increased rate of apoptotic cells when compared to the control group, indicating that lysosomal membrane permeabilization might occur in this model. Altogether, our results suggest that secondary alterations-as changes in Ca(2+) and H(+) homeostasis and lysosomal membrane permeabilization-may contribute for cellular damage and death in the physiopathology of MPS I.

Mutational and oxidative stress analysis in patients with mucopolysaccharidosis type I undergoing enzyme replacement therapy.

BACKGROUND: Mucopolysaccharidosis type I (MPS I) patients present a wide range of clinical manifestations, which could be due to the high molecular heterogeneity of the IDUA gene and to pathological events besides the enzyme deficiency. The aim of this study was to identify the most common MPS I causing mutations and to evaluate some oxidative stress markers in Brazilian patients. METHODS: 3 common mutations in the IDUA gene were searched in 11 MPS I patients by PCR-RFLP. Activities of antioxidant enzymes catalase and superoxide dismutase, and levels of total glutathione and thiobarbituric acid reactive substances were evaluated by spectrophotometric and colorimetric methods, during different periods of enzyme replacement therapy. RESULTS: The most common mutations were P533R and W402X, with allelic frequencies of 33.33% and 27.8% respectively. MPS I patients presented high levels of lipid peroxidation and enzyme replacement therapy led to an increase of catalase and a decrease of superoxide dismutase activities. CONCLUSIONS: P533R and W402X accounted for more than 60% of the alleles, but no genotype-phenotype correlation could be established. The alterations in antioxidant enzyme activities suggest that oxidative stress may be an important event among MPS I patients, which could contribute to the physiopathology of the disease.