Effect of β-Estradiol on Adipogenesis in a 3T3-L1 Cell Model of Prelamin A Accumulation

The accumulation of farnesylated prelamin A has been suggested as one of the mechanisms responsible for the loss of fat in type 2 familial partial lipodystrophy due to variants in the LMNA gene. In this rare disease, fat loss appears in women after puberty, affecting sex-hormone-dependent anatomical areas. This study investigated the impact of 17-β-estradiol on adipogenesis in murine preadipocytes subjected to a pharmacologically induced accumulation of farnesylated and non-farnesylated prelamin A. To induce the accumulation of non-farnesylated or farnesylated prelamin A, 3T3-L1 cells were treated with the farnesyltransferase inhibitor 277 or the methyltransferase inhibitor N-acetyl-S-farnesyl-l-cysteine methylester. Subsequently, the cells were induced to undergo adipocyte differentiation in the presence or absence of 17-β-estradiol. Prelamin A accumulation was assessed through immunofluorescence, while real-time PCR and Western blot techniques were used to quantify several adipogenic genes and evaluate protein levels, respectively. The results showed that 17-β-estradiol increased adipogenesis, although the combination of this hormone plus farnesylated prelamin A led to a reduction in the number of mature adipocytes and the expression of the different genes involved in adipogenesis. In conclusion, the influence of farnesylated prelamin A accumulation on adipogenesis manifested only in the presence of estradiol. These in vitro findings suggest a potential mechanism that could explain the characteristic phenotype in women suffering type 2 familial partial lipodystrophy.

Natural history and comorbidities of generalised and partial lipodystrophy syndromes in Spain

The rarity of lipodystrophies implies that they are not well-known, leading to delays in diagnosis/misdiagnosis. The aim of this study was to assess the natural course and comorbidities of generalised and partial lipodystrophy in Spain to contribute to their understanding. Thus, a total of 140 patients were evaluated (77.1% with partial lipodystrophy and 22.9% with generalised lipodystrophy). Clinical data were collected in a longitudinal setting with a median follow-up of 4.7 (0.5-17.6) years. Anthropometry and body composition studies were carried out and analytical parameters were also recorded. The estimated prevalence of all lipodystrophies in Spain, excluding Köbberling syndrome, was 2.78 cases/million. The onset of phenotype occurred during childhood in generalised lipodystrophy and during adolescence-adulthood in partial lipodystrophy, with the delay in diagnosis being considerable for both cohorts. There are specific clinical findings that should be highlighted as useful features to take into account when making the differential diagnosis of these disorders. Patients with generalised lipodystrophy were found to develop their first metabolic abnormalities sooner and a different lipid profile has also been observed. Mean time to death was 83.8 ± 2.5 years, being shorter among patients with generalised lipodystrophy. These results provide an initial point of comparison for ongoing prospective studies such as the ECLip Registry study.

A murine model of BSCL2-associated Celia's encephalopathy

Celia's encephalopathy or progressive encephalopathy with/without lipodystrophy is a neurodegenerative disease with a fatal prognosis in childhood. It is generally caused by the c.985C > T variant in the BSCL2 gene, leading to the skipping of exon 7 and resulting in an aberrant seipin protein (Celia-seipin). To precisely define the temporal evolution and the mechanisms involved in neurodegeneration, lipodystrophy and fatty liver in Celia's encephalopathy, our group has generated the first global knock-in murine model for the aberrant human transcript of BSCL2 (Bscl2Celia/Celia) using a strategy based on the Cre/loxP recombination system. In order to carry out a characterization at the neurological, adipose tissue and hepatic level, behavioral studies, brain PET, metabolic, histological and molecular studies were performed. Around 12% of homozygous and 5.4% of heterozygous knock-in mice showed severe neurological symptoms early in life, and their life expectancy was dramatically reduced. Severe generalized lipodystrophy and mild hepatic steatosis were present in these affected animals, while serum triglycerides and glucose metabolism were normal, with no insulin resistance. Furthermore, the study revealed a reduction in brain glucose uptake, along with patchy loss of Purkinje cells and the presence of intranuclear inclusions in cerebellar cortex cells. Homozygous, non-severely-affected knock-in mice showed a decrease in locomotor activity and greater anxiety compared with their wild type littermates. Bscl2Celia/Celia is the first murine model of Celia's encephalopathy which partially recapitulates the phenotype and severe neurodegenerative picture suffered by these patients. This model will provide a helpful tool to investigate both the progressive encephalopathy with/without lipodystrophy and congenital generalized lipodystrophy.

Lipodystrophy-associated progeroid syndromes

With the exception of HIV-associated lipodystrophy, lipodystrophy syndromes are rare conditions characterized by a lack of adipose tissue, which is not generally recovered. As a consequence, an ectopic deposition of lipids frequently occurs, which usually leads to insulin resistance, atherogenic dyslipidemia, and hepatic steatosis. These disorders include certain accelerated aging syndromes or progeroid syndromes. Even though each of them has unique clinical features, most show common clinical characteristics that affect growth, skin and appendages, adipose tissue, muscle, and bone and, in some of them, life expectancy is reduced. Although the molecular bases of these Mendelian disorders are very diverse and not well known, genomic instability is frequent as a consequence of impairment of nuclear organization, chromatin structure, and DNA repair, as well as epigenetic dysregulation and mitochondrial dysfunction. In this review, the main clinical features of the lipodystrophy-associated progeroid syndromes will be described along with their causes and pathogenic mechanisms, and an attempt will be made to identify which of López-Otín's hallmarks of aging are present.

Familial partial lipodystrophy syndromes

Lipodystrophies are a heterogeneous group of rare conditions characterised by the loss of adipose tissue. The most common forms are the familial partial lipodystrophy (FPLD) syndromes, which include a set of disorders, usually autosomal dominant, due to different pathogenetic mechanisms leading to improper fat distribution (loss of fat in the limbs and gluteal region and variable regional fat accumulation). Affected patients are prone to suffering serious morbidity via the development of metabolic complications associated to insulin resistance and an inability to properly store lipids. Although no well-defined diagnostic criteria have been established for lipodystrophy, there are certain clues related to medical history, physical examination and body composition evaluation that may suggest FPLD prior to confirmatory genetic analysis. Its treatment must be fundamentally oriented towards the control of the metabolic abnormalities. In this sense, metreleptin therapy, the newer classes of hypoglycaemic agents and other investigational drugs are showing promising results. This review aims to summarise the current knowledge of FPLD syndromes and to describe their clinical and molecular picture, diagnostic approaches and recent treatment modalities.

Variable Expressivity and Allelic Heterogeneity in Type 2 Familial Partial Lipodystrophy: The p.(Thr528Met) LMNA Variant

Type 2 familial partial lipodystrophy, or Dunnigan disease, is a metabolic disorder characterized by abnormal subcutaneous adipose tissue distribution. This rare condition results from variants principally affecting exons 8 and 11 of the LMNA gene. In this study, five FPLD2-diagnosed patients carrying the c.1583C>T, p.(Thr528Met) variant in exon 9 of the LMNA gene and with obvious clinical heterogeneity were evaluated. Specific polymorphisms in LMNA and in PPARG were also detected. Exhaustive clinical course, physical examination, biochemical features and family history were recorded, along with the assessment of anthropometric features and body composition by dual-energy X-ray absorptiometry. Preadipocytes obtained from a T528M patient were treated with the classic adipose differentiation medium with pioglitazone. Various adipogenes were evaluated by real-time PCR, and immunofluorescence was used to study intracellular localization of emerin, lamin A and its precursors. As demonstrated with Oil red O staining, the preadipocytes of the T528M patient failed to differentiate, the expression of various adipogenic genes was reduced in the lipodystrophic patient and immunofluorescence studies showed an accumulation of farnesylated prelamin A in T528M cells. We conclude that the T528M variant in LMNA could lead to FPLD2, as the adipogenic machinery is compromised.

Variable Expressivity in Type 2 Familial Partial Lipodystrophy Related to R482 and N466 Variants in the LMNA Gene

Patients with Dunnigan disease (FPLD2) with a pathogenic variant affecting exon 8 of the LMNA gene are considered to have the classic disease, whereas those with variants in other exons manifest the "atypical" disease. The aim of this study was to investigate the degree of variable expressivity when comparing patients carrying the R482 and N466 variants in exon 8. Thus, 47 subjects with FPLD2 were studied: one group of 15 patients carrying the N466 variant and the other group of 32 patients with the R482 variant. Clinical, metabolic, and body composition data were compared between both groups. The thigh skinfold thickness was significantly decreased in the R482 group in comparison with the N466 group (4.2 ± 1.8 and 5.6 ± 2.0 mm, respectively, p = 0.002), with no other differences in body composition. Patients with the N466 variant showed higher triglyceride levels (177.5 [56-1937] vs. 130.0 [55-505] mg/dL, p = 0.029) and acute pancreatitis was only present in these subjects (20%). Other classic metabolic abnormalities related with the disease were present regardless of the pathogenic variant. Thus, although FPLD2 patients with the R482 and N466 variants share most of the classic characteristics, some phenotypic and metabolic differences suggest possible heterogeneity even within exon 8 of the LMNA gene.

LipoDDx: a mobile application for identification of rare lipodystrophy syndromes

BACKGROUND

Lipodystrophy syndromes are a group of disorders characterized by a loss of adipose tissue once other situations of nutritional deprivation or exacerbated catabolism have been ruled out. With the exception of the HIV-associated lipodystrophy, they have a very low prevalence, which together with their large phenotypic heterogeneity makes their identification difficult, even for endocrinologists and pediatricians. This leads to significant delays in diagnosis or even to misdiagnosis. Our group has developed an algorithm that identifies the more than 40 rare lipodystrophy subtypes described to date. This algorithm has been implemented in a free mobile application, LipoDDx®. Our aim was to establish the effectiveness of LipoDDx®. Forty clinical records of patients with a diagnosis of certainty of most lipodystrophy subtypes were analyzed, including subjects without lipodystrophy. The medical records, blinded for diagnosis, were evaluated by 13 physicians, 1 biochemist and 1 dentist. Each evaluator first gave his/her results based on his/her own criteria. Then, a second diagnosis was given using LipoDDx®. The results were analysed based on a score table according to the complexity of each case and the prevalence of the disease.

RESULTS

LipoDDx® provides a user-friendly environment, based on usually dichotomous questions or choice of clinical signs from drop-down menus. The final result provided by this app for a particular case can be a low/high probability of suffering a particular lipodystrophy subtype. Without using LipoDDx® the success rate was 17 ± 20%, while with LipoDDx® the success rate was 79 ± 20% (p < 0.01).

CONCLUSIONS

LipoDDx® is a free app that enables the identification of subtypes of rare lipodystrophies, which in this small cohort has around 80% effectiveness, which will be of help to doctors who are not experts in this field. However, it will be necessary to analyze more cases in order to obtain a more accurate efficiency value.

Does Seipin Play a Role in Oxidative Stress Protection and Peroxisome Biogenesis? New Insights from Human Brain Autopsies

Seipin is a widely expressed protein but with highest levels found in the brain and testes. Seipin function is not yet completely understood, therefore the aim of this study was to evaluate the expression of BSCL2 transcripts in the central nervous system (CNS) of humans and investigate the effect of their overexpression on a neuron model and their relationship with oxidative stress protection, as well as shed light on the pathogenic mechanisms of Celia's Encephalopathy. We analyzed the expression of BSCL2 transcripts using real-time RT-PCR in samples across the brain regions of subjects who underwent necropsy and from a case with Celia's Encephalopathy. The transcript encoding the long seipin isoform (BSCL2-203, 462 aa) is expressed primarily in the brain and its expression is inversely correlated with age in the temporal lobe, amygdala, and hypothalamus. Strong positive correlations were found between BSCL2 expression and some genes encoding protective enzymes against oxidative stress including SOD1 and SOD2, as well as peroxisome proliferator-activated receptor gamma (PPARG) in the amygdala. These results were experimentally corroborated by overexpressing BSCL2 transcripts in SH-SY5Y cells with lentiviral transduction and assessing their effects on neuron differentiated cells. Confocal microscopy studies showed that both seipin and PEX16 are closely expressed in the hypothalami of healthy human brains, and PEX16 was absent in the same region of the PELD case. We hypothesize that seipin has specific CNS functions and may play a role in peroxisome biogenesis.

Inflammatory myopathy in the context of an unusual overlapping laminopathy

Laminopathies are genetic disorders associated with alterations in nuclear envelope proteins, known as lamins. The LMNA gene encodes lamins A and C, and LMNA mutations have been linked to diseases involving fat (type 2 familial partial lipodystrophy [FPLD2]), muscle (type 2 Emery-Dreifuss muscular dystrophy [EDMD2], type 1B limb-girdle muscular dystrophy [LGMD1B], and dilated cardiomyopathy), nerves (type 2B1 Charcot-Marie-Tooth disease), and premature aging syndromes. Moreover, overlapping syndromes have been reported. This study aimed to determine the genetic basis of an overlapping syndrome in a patient with heart disease, myopathy, and features of lipodystrophy, combined with severe metabolic syndrome. We evaluated a 54-year-old woman with rheumatoid arthritis, chronic hypercortisolism (endogenous and exogenous), and a history of cured adrenal Cushing syndrome. The patient presented with a complex disorder, including metabolic syndrome associated with mild partial lipodystrophy (Köbberling-like); mild hypertrophic cardiomyopathy, with Wolff-Parkinson- White syndrome and atrial fibrillation; and limb-girdle inflammatory myopathy. Mutational analysis of the LMNA gene showed a heterozygous c.1634G>A (p.R545H) variant in exon 10 of LMNA. This variant has previously been independently associated with FPLD2, EDMD2, LGMD1B, and heart disease. We describe a new, LMNA-associated, complex overlapping syndrome in which fat, muscle, and cardiac disturbances are related to a p.R545H variant.

Association of metreleptin treatment and dietary intervention with neurological outcomes in Celia's encephalopathy

Celia's encephalopathy (progressive encephalopathy with/without lipodystrophy, PELD) is a recessive neurodegenerative disease that is fatal in childhood. It is caused by a c.985C>T variant in the BSCL2/seipin gene that results in an aberrant seipin protein. We evaluated neurological development before and during treatment with human recombinant leptin (metreleptin) plus a dietary intervention rich in polyunsaturated fatty acids (PUFA) in the only living patient. A 7 years and 10 months old girl affected by PELD was treated at age 3 years with metreleptin, adding at age 6 omega-3 fatty acid supplementation. Her mental age was evaluated using the Battelle Developmental Inventory Screening Test (BDI), and brain PET/MRI was performed before treatment and at age 5, 6.5, and 7.5 years. At age 7.5 years, the girl remains alive and leads a normal life for her mental age of 30 months, which increased by 4 months over the last 18 months according to BDI. PET images showed improved glucose uptake in the thalami, cerebellum, and brainstem. This patient showed a clear slowdown in neurological regression during leptin replacement plus a high PUFA diet. The aberrant BSCL2 transcript was overexpressed in SH-SY5Y cells and was treated with docosahexaenoic acid (200 µM) plus leptin (0.001 mg/ml) for 24 h. The relative expression of aberrant BSCL2 transcript was measured by qPCR. In vitro studies showed significant reduction (32%) in aberrant transcript expression. This therapeutic approach should be further studied in this devastating disease.

Bone mineral density in familial partial lipodystrophy

OBJECTIVE

Type 1 and type 2 familial partial lipodystrophies (FPLD) are characterized by the loss or increase in subcutaneous fat in certain body regions, as well as metabolic disorders. Higher muscle volume and mass have also been described. However, so far, possible bone involvement has not been studied. The aim of this study was to evaluate bone mineral density (BMD) in patients with type 1 and type 2 FPLD.

METHODS

A total of 143 women were selected and distributed into three groups (17 women with FPLD2, 82 women with FPLD1 and 44 nonlipodystrophic obese female controls). A thorough history and physical examination were carried out on all subjects, as well as the measurement of anthropometric features. BMD along with fat and fat-free mass (FFM) were determined by DXA (dual-energy X-ray absorptiometry). Statistical analyses, primarily using the χ² , ANOVA and ANCOVA tests, were performed, using age, height, fat and FFM as covariables.

RESULTS

After eliminating the possible influences of age, height, fat and FFM, we observed that there were no significant differences in total BMD between patients with FPLD and the control group, showing total BMD values of 1.092 ± 0.037 g/cm² in the FPLD2 group, 1.158 ± 0.013 g/cm² in the FPLD1 group and 1.173 ± 0.018 g/cm² in the control group (P = .194). Similarly, no significant differences were found in segmental BMD.

CONCLUSIONS

Unlike in other types of laminopathy in which bone is affected, in the case of FPLD, there are no differences in BMD compared to nonlipodystrophic subjects.

Lipodystrophic laminopathies: Diagnostic clues

The nuclear lamina is a complex reticular structure that covers the inner face of the nucleus membrane in metazoan cells. It is mainly formed by intermediate filaments called lamins, and exerts essential functions to maintain the cellular viability. Lamin A/C provides mechanical steadiness to the nucleus and regulates genetic machinery. Laminopathies are tissue-specific or systemic disorders caused by variants in LMNA gene (primary laminopathies) or in other genes encoding proteins which are playing some role in prelamin A maturation or in lamin A/C function (secondary laminopathies). Those disorders in which adipose tissue is affected are called laminopathic lipodystrophies and include type 2 familial partial lipodystrophy and certain premature aging syndromes. This work summarizes the main clinical features of these syndromes, their associated comorbidities and the clues for the differential diagnosis with other lipodystrophic disorders.

LMNA missense mutations causing familial partial lipodystrophy do not lead to an accumulation of prelamin A

A variety of missense mutations in LMNA (the gene for lamin C and prelamin A) cause familial partial lipodystrophy (FPLD), a disease associated with reduced adipose tissue, particularly in the limbs. Several studies have reported that fibroblasts from FPLD subjects have an accumulation of prelamin A. Those findings were intriguing but also perplexing because many of the LMNA missense mutations associated with lipodystrophy are located in sequences distant from the sequences required for the farnesylation of prelamin A and ZMPSTE24-mediated conversion of prelamin A to mature lamin A. Here, we revisited the issue of prelamin A accumulation in the setting of FPLD mutations. We used western blots with lamin A/C antibodies and prelamin A-specific monoclonal antibodies to assess prelamin A levels in wild-type fibroblasts and fibroblasts carrying LMNA mutations associated with lipodystrophy (R482W, I299V, C591F, T528M). None of the mutant fibroblasts exhibited an accumulation of prelamin A. Also, the amount of prelamin A accumulation in response to lopinavir (an inhibitor of ZMPSTE24) was similar in wild-type and mutant fibroblasts. Thus, the LMNA lipodystrophy mutations that we examined did not lead to prelamin A accumulation, nor did they render those cells more susceptible to prelamin A accumulation when ZMPSTE24 was inhibited by lopinavir.

Type 1 familial partial lipodystrophy: understanding the Köbberling syndrome

Familial partial lipodystrophy are Mendelian disorders involving abnormal body fat distribution and insulin resistance. The current classification includes the Köbberling syndrome (type 1 familial partial lipodystrophy), characterized by fat loss in the lower limbs and abnormal fat accumulation in other areas. Type 1 familial partial lipodystrophy appears to be heritable, but little is known about it, including putative contributing mutations. We aimed to characterize this syndrome better by evaluating a group of women with phenotypic features of type 1 familial partial lipodystrophy. This is a case-controlled study in which 98 women with type 1 familial partial lipodystrophy that lacked classical mutations known to cause familial partial lipodystrophy were compared with 60 women without lipodystrophy and 25 patients with type 2 familial partial lipodystrophy (Dunnigan disease). Clinical course, body composition by dual-energy X-ray absorptiometry, HbA1c, lipid profile, insulin, leptin and family history were evaluated in all of the participants. Analyses of receiver-operating characteristic curve were performed for type 1 familial partial lipodystrophy diagnosis, comparing different truncal/limbs ratios. Among patients with type 1 familial partial lipodystrophy, 68 % developed recognizable lipodystrophy before adolescence, and most displayed an autosomal-dominant pattern (86 %). Women with type 1 familial partial lipodystrophy had less lower-limb adipose tissue than women without lipodystrophy, but significantly more than patients with Dunnigan disease. Moreover, metabolic disturbances occurred more frequently in the type 1 familial partial lipodystrophy group (81 %) than in the non-lipodystrophic group (30 %, p<0.05). The severity of metabolic disturbances was inversely proportional to the percentage of fat in the lower extremities and directly proportional to the amount of visceral adipose tissue. Metabolic profiles were worse in type 1 familial partial lipodystrophy than in Dunnigan disease. According to the receiver-operating characteristic curve analysis, the best ratio was subscapular/calf skinfolds (KöB index), with a cut-off value of 3.477 (sensitivity: 89 %; specificity: 84 %). Type 1 familial partial lipodystrophy was an early-onset, autosomal-dominant lipodystrophy, characterized by fat loss in the lower limbs and abnormal fat accumulation in the abdominal visceral region, associated to insulin resistance and metabolic disorders. A KöB index >3.477 is highly suggestive of this syndrome.

Skipped BSCL2 Transcript in Celia's Encephalopathy (PELD): New Insights on Fatty Acids Involvement, Senescence and Adipogenesis

OBJECTIVE

PELD (Progressive Encephalopathy with or without Lipodystrophy or Celia's Encephalopathy) is a fatal and rare neurodegenerative syndrome associated with the BSCL2 mutation c.985C>T, that results in an aberrant transcript without the exon 7 (Celia seipin). The aim of this study was to evaluate both the process of cellular senescence and the effect of unsaturated fatty acids on preadipocytes from a homozygous c.985C>T patient. Also, the role of aberrant seipin isoform on adipogenesis was studied in adipose-derived human mesenchymal stem cells.

MATERIAL AND METHODS

Cellular senescence was evaluated using β-galactosidase staining of preadipocytes obtained from a homozygous c.985C>T patient. Moreover, these cells were cultured during 24 hours with Intralipid, a soybean oil-based commercial lipid emulsion. The expression of the different BSCL2 transcripts was measured by qPCR. Adipose-derived human mesenchymal stem cells were differentiated to a fat lineage using StemPRO adipogenesis kit, and the expression of BSCL2 transcripts and several adipogenesis-related genes was measured by qPCR.

RESULTS

the treatment of preadipocytes with unsaturated fatty acids significantly reduced the expression of the BSCL2 transcript without exon 7 by 34 to 63%. On the other hand, at least in preadipocytes, this mutation does not disturb cellular senescence rate. Finally, during adipocyte differentiation of adipose-derived human mesenchymal stem cells, the expression of adipogenic genes (PPARG, LPIN1, and LPL) increased significantly over 14 days, and noteworthy is that the BSCL2 transcript without exon 7 was differentially expressed by 332 to 723% when compared to day 0, suggesting an underlying role in adipogenesis.

CONCLUSIONS

our results suggest that Celia seipin is probably playing an underestimated role in adipocyte maturation, but not in senescence, and its expression can be modified by exogenous factors as fatty acids.

Larger aggregates of mutant seipin in Celia's Encephalopathy, a new protein misfolding neurodegenerative disease

Celia's Encephalopathy (MIM #615924) is a recently discovered fatal neurodegenerative syndrome associated with a new BSCL2 mutation (c.985C>T) that results in an aberrant isoform of seipin (Celia seipin). This mutation is lethal in both homozygosity and compounded heterozygosity with a lipodystrophic BSCL2 mutation, resulting in a progressive encephalopathy with fatal outcomes at ages 6-8. Strikingly, heterozygous carriers are asymptomatic, conflicting with the gain of toxic function attributed to this mutation. Here we report new key insights about the molecular pathogenic mechanism of this new syndrome. Intranuclear inclusions containing mutant seipin were found in brain tissue from a homozygous patient suggesting a pathogenic mechanism similar to other neurodegenerative diseases featuring brain accumulation of aggregated, misfolded proteins. Sucrose gradient distribution showed that mutant seipin forms much larger aggregates as compared with wild type (wt) seipin, indicating an impaired oligomerization. On the other hand, the interaction between wt and Celia seipin confirmed by coimmunoprecipitation (CoIP) assays, together with the identification of mixed oligomers in sucrose gradient fractionation experiments can explain the lack of symptoms in heterozygous carriers. We propose that the increased aggregation and subsequent impaired oligomerization of Celia seipin leads to cell death. In heterozygous carriers, wt seipin might prevent the damage caused by mutant seipin through its sequestration into harmless mixed oligomers.

Recombinant human leptin treatment in genetic lipodystrophic syndromes: the long-term Spanish experience

Lipodystrophies are a group of diseases mainly characterized by a loss of adipose tissue and frequently associated with insulin resistance, hypertriglyceridemia, and hepatic steatosis. In uncommon lipodystrophies, these complications frequently are difficult to control with conventional therapeutic approaches. This retrospective study addressed the effectiveness of recombinant methionyl leptin (metreleptin) for improving glucose metabolism, lipid profile, and hepatic steatosis in patients with genetic lipodystrophic syndromes. We studied nine patients (five females and four males) with genetic lipodystrophies [seven with Berardinelli-Seip syndrome, one with atypical progeroid syndrome, and one with type 2 familial partial lipodystrophy (FPLD)]. Six patients were children under age 9 years, and all patients had baseline triglycerides levels >2.26 mmol/L and hepatic steatosis; six had poorly controlled diabetes mellitus. Metreleptin was self-administered subcutaneously daily at a final dose that ranged between 0.05 and 0.24 mg/(kg day) [median: 0.08 mg/(kg day)] according to the body weight. The duration of treatment ranged from 9 months to 5 years, 9 months (median: 3 years). Plasma glucose, hemoglobin A1c (Hb A1c), lipid profile, plasma insulin and leptin, and hepatic enzymes were evaluated at baseline and at least every 6 months. Except for the patient with FPLD, metreleptin replacement significantly improved metabolic control (Hb A1c: from 10.4 to 7.1 %, p < 0.05). Plasma triglycerides were reduced 76 % on average, and hepatic enzymes decreased more than 65 %. This study extends knowledge about metreleptin replacement in genetic lipodystrophies, bearing out its effectiveness for long periods of time.

A new seipin-associated neurodegenerative syndrome

BACKGROUND

Seipin/BSCL2 mutations can cause type 2 congenital generalised lipodystrophy (BSCL) or dominant motor neurone diseases. Type 2 BSCL is frequently associated with some degree of intellectual impairment, but not to fatal neurodegeneration. In order to unveil the aetiology and pathogenetic mechanisms of a new neurodegenerative syndrome associated with a novel BSCL2 mutation, six children, four of them showing the BSCL features, were studied.

METHODS

Mutational and splicing analyses of BSCL2 were performed. The brain of two of these children was examined postmortem. Relative expression of BSCL2 transcripts was analysed by real-time reverse transcription-polymerase chain reaction (RT-PCR) in different tissues of the index case and controls. Overexpressed mutated seipin in HeLa cells was analysed by immunofluorescence and western blotting.

RESULTS

Two patients carried a novel homozygous c.985C>T mutation, which appeared in the other four patients in compound heterozygosity. Splicing analysis showed that the c.985C>T mutation causes an aberrant splicing site leading to skipping of exon 7. Expression of exon 7-skipping transcripts was very high with respect to that of the non-skipped transcripts in all the analysed tissues of the index case. Neuropathological studies showed severe neurone loss, astrogliosis and intranuclear ubiquitin(+) aggregates in neurones from multiple cortical regions and in the caudate nucleus.

CONCLUSIONS

Our results suggest that exon 7 skipping in the BSCL2 gene due to the c.985C>T mutation is responsible for a novel early onset, fatal neurodegenerative syndrome involving cerebral cortex and basal ganglia.

A simple method for isolating rat brain mitochondria with high metabolic activity: effects of EDTA and EGTA

Isolated mitochondria are widely used in metabolic and oxidative stress studies for neurodegenerative diseases. In the present work, the influence of EGTA and EDTA has been tested on a sucrose-based differential centrifugation protocol in order to establish the optimal concentrations to be used in this process. Our results showed alterations in both active and resting respiration, which were dependent on both the addition of EDTA or EGTA to the isolation buffer and the chelator concentration used. However, the addition of chelator to the isolation medium does not modify the mitochondria structure as assessed by both distribution of biological markers and electron micrography in the final pellet. Our results endorse this protocol as the method of choice for metabolic and oxidative stress experiments with fresh isolated rat brain mitochondria.

Differential toxicity of 6-hydroxydopamine in SH-SY5Y human neuroblastoma cells and rat brain mitochondria: protective role of catalase and superoxide dismutase

Oxidative stress and mitochondrial dysfunction are two pathophysiological factors often associated with the neurodegenerative process involved in Parkinson's disease (PD). Although, 6-hydroxydopamine (6-OHDA) is able to cause dopaminergic neurodegeneration in experimental models of PD by an oxidative stress-mediated process, the underlying molecular mechanism remains unclear. It has been established that some antioxidant enzymes such as catalase (CAT) and superoxide dismutase (SOD) are often altered in PD, which suggests a potential role of these enzymes in the onset and/or development of this multifactorial syndrome. In this study we have used high-resolution respirometry to evaluate the effect of 6-OHDA on mitochondrial respiration of isolated rat brain mitochondria and the lactate dehydrogenase cytotoxicity assay to assess the percentage of cell death induced by 6-OHDA in human neuroblastoma cell line SH-SY5Y. Our results show that 6-OHDA affects mitochondrial respiration by causing a reduction in both respiratory control ratio (IC(50) = 200 ± 15 nM) and state 3 respiration (IC(50) = 192 ± 17 nM), with no significant effects on state 4(o). An inhibition in the activity of both complex I and V was also observed. 6-OHDA also caused cellular death in human neuroblastoma SH-SY5Y cells (IC(50) = 100 ± 9 μM). Both SOD and CAT have been shown to protect against the toxic effects caused by 6-OHDA on mitochondrial respiration. However, whereas SOD protects against 6-OHDA-induced cellular death, CAT enhances its cytotoxicity. The here reported data suggest that both superoxide anion and hydroperoxyl radical could account for 6-OHDA toxicity. Furthermore, factors reducing the rate of 6-OHDA autoxidation to its p-quinone appear to enhance its cytotoxicity.

Analysis of brain regional distribution of aluminium in rats via oral and intraperitoneal administration

In the present work, accumulation and distribution of aluminium in the rat brain following both intraperitoneal and oral administration were studied. Electrothermal atomic absorption spectrometry was used to determine aluminium concentration in different brain areas (cerebellum, ventral midbrain, cortex, hippocampus, and striatum). Most of the brain areas showed accumulation of aluminium, but a greater and more significant increase was noted in the group receiving aluminium via intraperitoneal administration. Aluminium distribution was also dependent on the administration route.

Time-course of brain oxidative damage caused by intrastriatal administration of 6-hydroxydopamine in a rat model of Parkinson's disease

The unilateral and intrastriatal injection of 6-hydroxydopamine is commonly used to provide a partial lesion model of Parkinson's disease in the investigation of the molecular mechanisms involved in its pathogenesis and to assess new neuroprotective treatments. Its capacity to induce neurodegeneration has been related to its ability to undergo autoxidation in the presence of oxygen and consequently to generate oxidative stress. The aim of the present study was to investigate the time course of brain oxidative damage induced by 6-hydroxydopamine (6 microg in 5 microl of sterile saline containing 0.2% ascorbic acid) injection in the right striatum of the rat. The results of this study show that the indices of both lipid peroxidation (TBARS) and protein oxidation (carbonyl and free thiol contents) increase simultaneously in the ipsilateral striatum and ventral midbrain, reaching a peak value at 48-h post-injection for both TBARS and protein carbonyl content, and at 24 h for protein free thiol content. A lower but significant increase was also observed in the contralateral side (striatum and ventral midbrain). The indices of oxidative stress returned to values close to those found in controls at 7-day post-injection. These data show that the oxidative stress is a possible triggering factor for the neurodegenerative process and the retrograde neurodegeneration observed after 1-week post-injection is a consequence of the cell damage caused during the first days post-injection. The optimal time to assess brain indices of oxidative stress in this model is 48-h post-injection.

Study on the ability of 1,2,3,4-tetrahydropapaveroline to cause oxidative stress: Mechanisms and potential implications in relation to parkinson's disease

Tetrahydropapaveroline (THP) is a compound derived from dopamine monoamine oxidase-mediated metabolism, particularly present in the brain of parkinsonian patients receiving L-dopa therapy, and is capable of causing dopaminergic neurodegeneration. The aim of this work was to evaluate the potential of THP to cause oxidative stress on mitochondrial preparations and to gain insight into the molecular mechanisms responsible for its neurotoxicity. Our data show that THP autoxidation occurs with a continuous generation of hydroxyl radicals (*OH) and without the involvement of the Fenton reaction. The presence of ascorbate enhances this process by establishing a redox cycle, which regenerates THP from its quinolic forms. It has been shown that the production of *OH is not affected by the presence of either ferrous or ferric iron. Although THP does not affect lipid peroxidation, it is capable of reducing the high levels of thiobarbituric acid-reactive substances obtained in the presence of ascorbate and/or iron. However, THP autoxidation in the presence of ascorbate causes both an increase in protein carbonyl content and a reduction in protein-free thiol content. THP also increases protein carbonyl content when the autoxidation occurs in the presence of iron. The remarkable role played by ascorbate in the production of oxidative stress by THP autoxidation is of particular interest.

Autoxidation and MAO-mediated metabolism of dopamine as a potential cause of oxidative stress: role of ferrous and ferric ions

The autoxidation and monoamine oxidase (MAO)-mediated metabolism of dopamine (3-hydroxytyramine; DA) cause a continuous production of hydroxyl radical (*OH), which is further enhanced by the presence of iron (ferrous iron, Fe(2+) and ferric ion, Fe(3+)). The accumulation of hydrogen peroxide (H2O2) in the presence of Fe(2+) appears to discard the involvement of the Fenton reaction in this process. It has been found that the presence of DA significantly reduces the formation of thiobarbituric acid reagent substances (TBARS), which under physiological conditions takes place in mitochondrial preparations. The presence of DA is also able to reduce TBARS formation in mitochondrial preparations even in the presence of iron (Fe(2+) and Fe(3+)). However, DA boosted the carbonyl content of mitochondrial proteins, which was further increased in the presence of iron (Fe(2+) and Fe(3+)). This latter effect is also accompanied by a significant reduction in thiol content of mitochondrial proteins. It has also been observed how the pre-incubation of mitochondria with pargyline, an acetylenic MAO inhibitor, reduces the production of *OH and increases the formation of TBARS. Although, the MAO-mediated metabolism of DA increases MAO-B activity, the presence of iron inhibits both MAO-A and MAO-B activities. Consequently, DA has been shown to be a double-edged sword, because it displays antioxidant properties in relation to both the Fenton reaction and lipid peroxidation and exhibits pro-oxidant properties by causing both generation *OH and oxidation of mitochondrial proteins. Evidently, these pro-oxidant properties of DA help explain the long-term side effects derived from l-DOPA treatment of Parkinson's disease and its exacerbation by the concomitant use of DA metabolism inhibitors.

[Sexual dysfunction with antidepressive agents. Effect of the change to amineptine in patients with sexual dysfunction secondary to SSRI]

Sexual dysfunction secondary to the use of antidepressants, especially clomipramine or SSRI's is an adverse effect that is often underestimated and according to earlier studies, this can affect approximately 60% of the patients. This presents as a decrease in libido, alterations in the ability to reach orgasm/ejaculation, and an erectile dysfunction or a decreased vaginal lubrication. This dysfunction appears to be related with the resulting increase in serotonin and with the stimulation of serotonin 5HT2 receptors.

OBJECTIVES

1) Evaluate the effect of amineptine, a drug with an increased dopamine transmission and scant serotonin transmission, on the sexual function of depressed patients who begin treatment, and 2) evaluate whether the change to amineptine improves the sexual function in patients who presented sexual dysfunction after beginning treatment with a SSRI.

MATERIAL AND METHODS

Prospective, observational, open and multicentric design. 111 patients with an average age of 41.3 years (36 men, 75 women) were distributed into three groups: Group 1 (n= 26): patients with depression (DSM IV) who begin de novo treatment with amineptine 200 mg/day. Group 2 (n= 47): depressed patients undergoing treatment with a SSRI who show a favorable response and who present sexual dysfunction secondary to a poorly tolerated treatment, so the treatment is changed to 200 mg/day of amineptine. Group 3 (n= 38): patients with the same characteristics as those of group 2, but whose treatment was changed to 20 mg/day of paroxetine. The <<Questionnaire for the Measure of Sexual Dysfunction Secondary to the use of Psychotropic Drugs>> (Montejo et al, 1996) was used together with the Hamilton Depression Scale, the IGC Scale, and an adverse events scale, over a 6 months follow up period during which visits took place at: baseline, month 1, month 2, month 3, and month 6.

RESULTS

In group 1, treated with amineptine from the beginning, of the 5 patients who showed a decrease in the libido at the beginning of the treatment, only one still presented this in the 6th month. The Hamilton Scale decreased from 23.12 (baseline) to 5.25 after 6 months. After substituting amineptine for SSRI's in patients with sexual dysfunction, the incidence of any type of sexual dysfunction decreased significantly from 100% (baseline) to 55.3% after 6 months. (P< 0.001). The incidence of delayed orgasm dropped to 15.8%, anorgasmia to 17.4%, and impotence dropped to 15.8% in this group, with the antidepressant effect that had already been achieved with the SSRI being maintained. However, in group 3 there was barely any improvement on the sexual function after changing to paroxetine (20 mg/day), with the baseline incidence being 100% and the incidence after 6 months being 89.7%. In this last group the antidepressant effect present at the baseline level, was maintained.

CONCLUSIONS

Amineptine was shown to be an effective antidepressant in the patients studied, and did not cause secondary sexual dysfunction, and even improved the dysfunction that was present in some patients. In those patients previously treated with SSRI's, amineptine is able to significantly improve the sexual dysfunction and yet maintain the efficacy of the antidepressive treatment used before these 6 months. On the other hand, Paroxetine did not improve the sexual dysfunction of the people in whom this drug substituted another SSRI, as this is an adverse effect common to the entire group of selective serotonin re-uptake inhibiting drugs. Amineptine showed a good safety and tolerance profile. Its most common side effect (anxiety/restlessness) disappeared 2 months after the beginning of the treatment.