Drosophila melanogaster Models of Friedreich's Ataxia

Friedreich's ataxia (FRDA) is a rare inherited recessive disorder affecting the central and peripheral nervous systems and other extraneural organs such as the heart and pancreas. This incapacitating condition usually manifests in childhood or adolescence, exhibits an irreversible progression that confines the patient to a wheelchair, and leads to early death. FRDA is caused by a reduced level of the nuclear-encoded mitochondrial protein frataxin due to an abnormal GAA triplet repeat expansion in the first intron of the human FXN gene. FXN is evolutionarily conserved, with orthologs in essentially all eukaryotes and some prokaryotes, leading to the development of experimental models of this disease in different organisms. These FRDA models have contributed substantially to our current knowledge of frataxin function and the pathogenesis of the disease, as well as to explorations of suitable treatments. Drosophila melanogaster, an organism that is easy to manipulate genetically, has also become important in FRDA research. This review describes the substantial contribution of Drosophila to FRDA research since the characterization of the fly frataxin ortholog more than 15 years ago. Fly models have provided a comprehensive characterization of the defects associated with frataxin deficiency and have revealed genetic modifiers of disease phenotypes. In addition, these models are now being used in the search for potential therapeutic compounds for the treatment of this severe and still incurable disease.

Diamine oxidase levels in different chronic urticaria phenotypes

BACKGROUND

Diamine oxidase (DAO) is a polyamine-degrading enzyme also implicated in histamine metabolism. Chronic urticaria (CU) has a wide spectrum of clinical presentations and causes. Anisakis sensitisation associated chronic urticaria (CU+) has been characterised as a phenotype with different clinical and immunological characteristics and possibly associated with previous acute parasitism. We aimed to analyse serum DAO levels in different CU phenotypes. We further analysed the possible association of DAO with fish eating habits.

METHODS

We studied 35 CU+ patients and 39 non-sensitised CU patients (CU-) as well as 19 controls. We analysed fish-eating frequency as well as fish intake associated exacerbation of CU (FIAE) or gastro-intestinal complaints (GI). DAO levels were further analysed with respect to lymphoproliferative responses, cytokine and specific IgE production.

RESULTS

DAO levels were not different between CU and controls, but were significantly higher in CU+ than in CU-. CU+ patients with FIAE had lower DAO levels, but no differences were detected in patients with GI. DAO levels correlated positively with oily and canned fish consumption in CU-. In CU+, DAO levels correlated positively with specific Anisakis IgE, percentages of proliferation in Anisakis stimulated peripheral blood lymphocytes, serum IL-2 and IL-6, but correlated negatively with mitogen stimulated TGF-β in supernatants.

CONCLUSIONS

DAO levels in CU depend on fish-eating habits and in CU+ on the amount of specific IgE production. In the CU+ phenotype, lower levels of DAO predispose to urticaria exacerbation after fish intake, probably due to a relative insufficient enteric availability of this enzyme.

[Digestive disorders in Parkinson's disease: dysphagia and sialorrhea]

INTRODUCTION

The non-motor symptoms of Parkinson's disease are a frequent and often under-diagnosed disorder. Two of the most significant non-motor symptoms are perhaps dysphagia and sialorrhea (which are relatively common in advanced stages of the disease) owing to their important functional repercussions and to the associated comorbidity.

DEVELOPMENT AND CONCLUSIONS

In recent years, different evaluation scales have been developed for clinical use and in screening the aforementioned symptoms. Of the different therapeutic options available, botulinum toxin represents the preferred treatment for sialorrhea. In contrast, speech therapy and an optimisation of the antiparkinsonian therapy are generally useful measures to treat dysphagia, percutaneous endoscopic gastrostomy being reserved for patients suffering from Parkinson who have severe dysphagia.

[Locomotion and gait disorders]

INTRODUCTION

Human beings are characterised by the specialisation of certain functions, such as language or the ability to walk. We have achieved this capacity thanks to the development of multiple connections among different areas of the central and peripheral nervous system, together with adaptation of the musculoskeletal system. These are all essential to be able to walk correctly and to keep our balance.

DEVELOPMENT

Gait disorders are currently receiving a great deal of attention in neurology departments, and this fact is directly related to the phenomenon of the ageing of the population, since it is a pathology that is particularly prevalent among the elderly. One of the fundamental mainstays in the study of these disorders is being able to distinguish between the different clinical gait patterns and their classification according to the neural system that has been damaged. Observation, the use of different manoeuvres in the examination and the search for other associated clinical signs all enable us reach a good diagnostic approximation, which will later be confirmed with more specific complementary techniques.

CONCLUSIONS

From the therapeutic point of view, an early multidisciplinary intervention by the neurologist, primary care, specialists in rehabilitation and physiotherapists improves patients' quality of life and lowers the rate of associated comorbidity and mortality, which also results in a reduction in spending on community health resources.