Efficacy of discontinuing risedronate for patients with systemic lupus erythematosus: a prospective study.

Objective The objective of this study is to investigate the effectiveness of discontinuation of risedronate for patients with systemic lupus erythematosus (SLE) treated with glucocorticoid (GC). Methods The participants were patients with SLE treated with prednisolone (PSL) ≥ 2 mg/day and risedronate for at least three years. Lumbar spine and total hip bone mineral density (BMD) measurements were taken at baseline and 24 and 48 weeks after discontinuation of risedronate, and bone turnover markers were evaluated at baseline, 12, 24, 36, and 48 weeks. Results A total of 36 patients were enrolled, 25 of whom discontinued risedronate. The mean age was 46.8 ± 11.2 years, and 23 were female. The mean duration of GC treatment was 14.8 ± 11.4 years, the mean dose of PSL was 7.8 ± 3.9 mg/day, and the mean duration of risedronate was 5.8 ± 2.4 years. Seventeen patients showed decreased lumbar spine BMD at 48 weeks after discontinuation of risedronate, with a mean lumbar spine lumbar decrease of 1.42% ± 3.20% ( p = 0.034); 17 patients (71%) showed a decreased total hip BMD at 48 weeks after discontinuation of risedronate, with a mean total hip BMD decrease of 0.99% ± 2.10% ( p = 0.021). Serum tartrate-resistant acid phosphatase 5b (TRACP-5b) ≥ 309 mU/dl at baseline was a risk factor for decreased total hip BMD at 48 weeks compared with serum TRACP-5b < 309 mU/dl (56% vs 0%, p = 0.0098). One patient developed a clinical fracture of the lumbar spine at 20 weeks. Conclusions Discontinuation of risedronate treatment in patients with SLE who had received GC therapy led to decreases in lumbar spine and total hip BMD, particularly in patients with high baseline serum TRACP-5b levels.

Changes in the blood level, efficacy, and safety of tacrolimus in pregnancy and the lactation period in patients with systemic lupus erythematosus.

OBJECTIVES: We investigated the efficacy and safety of tacrolimus (TAC) by monitoring its serum concentration for mothers and infants in pregnant patients with systemic lupus erythematosus (SLE). METHODS: We measured trough concentrations of TAC in 25 pregnant patients with SLE to assess influence of TAC on the disease activity. Additionally, we measured the concentrations of TAC in umbilical arterial blood, breast milk, and breastfed infants to investigate the safety of TAC for the mothers and infants. RESULTS: The trough concentrations of TAC in the mothers significantly decreased in the second trimester as compared with those before pregnancy. However, the decrease in the trough concentrations of TAC did not lead to the deterioration of SLE. When examined, the doses of TAC were significantly lower in the second trimester and postpartum in the deteriorating group than those in the non-deteriorating group. There were no adverse events by TAC in mothers and fetuses. The concentrations of TAC in the umbilical cord blood were lower than those in the maternal blood. The relative infant dose in breastfed infants of TAC was < 1%. The level of TAC in infant bloods was below detectable limits. CONCLUSION: These findings suggest that TAC is one of the most effective and safest immunosuppressive drugs for use in pregnant patients with SLE.

Nicastrin binds to membrane-tethered Notch.

The presenilins and nicastrin, a type 1 transmembrane glycoprotein, form high molecular weight complexes that are involved in cleaving the beta-amyloid precursor protein (betaAPP) and Notch in their transmembrane domains. The former process (termed gamma-secretase cleavage) generates amyloid beta-peptide (Abeta), which is involved in the pathogenesis of Alzheimer's disease. The latter process (termed S3-site cleavage) generates Notch intracellular domain (NICD), which is involved in intercellular signalling. Nicastrin binds both full-length betaAPP and the substrates of gamma-secretase (C99- and C83-betaAPP fragments), and modulates the activity of gamma-secretase. Although absence of the Caenorhabditis elegans nicastrin homologue (aph-2) is known to cause an embryonic-lethal glp-1 phenotype, the role of nicastrin in this process has not been explored. Here we report that nicastrin binds to membrane-tethered forms of Notch (substrates for S3-site cleavage of Notch), and that, although mutations in the conserved 312-369 domain of nicastrin strongly modulate gamma-secretase, they only weakly modulate the S3-site cleavage of Notch. Thus, nicastrin has a similar role in processing Notch and betaAPP, but the 312-369 domain may have differential effects on these activities. In addition, we report that the Notch and betaAPP pathways do not significantly compete with each other.

A polymorphism of the aldehyde dehydrogenase 2 gene is a risk factor for multiple lacunar infarcts in Japanese men: the Takahata Study.

The objective of the present study was to examine the association between a polymorphism of the aldehyde dehydrogenase 2 (ALDH2) gene and lacunar infarcts of the brain. We conducted a population-based, cross-sectional study on residents from two age groups (61- and 72-year olds). A total of 376 subjects participated in the study, which included brain magnetic resonance image and genetic analysis of the ALDH2 gene. Of the 61- and 72-year-old subjects, 46.4% and 64.3%, respectively, had one or more lacunar infarcts. The average number of infarcts also increased from 2.0 to 2.8 in men and from 2.3 to 3.5 in women. No significant association between the ALDH2 genotype and the presence of lacunar infarction (> or =1) was found. However, in subjects with lacunar infarction, the genotype of ALDH2 *1/*1 was associated with a larger number of the lesion ['single' versus 'multiple' odds ratio (OR) 3.73, 95%CI: 1.43-9.74] in men. The OR was comparable even after adjusting for alcohol consumption, tobacco habits, age, hypertension, hypercholesterolemia, and diabetes mellitus (DM) (OR 3.88; 95% CI: 1.10-13.66). In women, there was no significant association between the ALDH2 genotypes and lacunar infarcts. The present study revealed that the ALDH2 *1/*1 genotype was significantly associated with the prevalence of multiple lacunar infarcts in Japanese men.

Presenilin structure, function and role in Alzheimer disease.

Numerous missense mutations in the presenilins are associated with the autosomal dominant form of familial Alzheimer disease. Presenilin genes encode polytopic transmembrane proteins, which are processed by proteolytic cleavage and form high-molecular-weight complexes under physiological conditions. The presenilins have been suggested to be functionally involved in developmental morphogenesis, unfolded protein responses and processing of selected proteins including the beta-amyloid precursor protein. Although the underlying mechanism by which presenilin mutations lead to development of Alzheimer disease remains elusive, one consistent mutational effect is an overproduction of long-tailed amyloid beta-peptides. Furthermore, presenilins interact with beta-catenin to form presenilin complexes, and the physiological and mutational effects are also observed in the catenin signal transduction pathway.

Mutation of conserved aspartates affect maturation of presenilin 1 and presenilin 2 complexes.

Presenilin (PS1 and PS2) holoproteins are transiently incorporated into low molecular weight (MW) complexes. During subsequent incorporation into a higher MW complex, they undergo endoproteolysis to generate stable N- and C-terminal fragments (NTF/CTF). Mutation of either of two conserved aspartate residues in transmembrane domains inhibits both presenilin-endoproteolysis and the proteolytic processing of APP and Notch. We show that aspartate-mutant holoprotein presenilins are not incorporated into the high molecular weight, NTF/CTF-containing complexes. Aspartate-mutant presenilin holoproteins also preclude entry of endogenous wild-type PS1/PS2 into the high molecular weight complexes, but do not affect the incorporation of wild-type holoproteins into lower molecular weight holoprotein complexes. These data suggest that the loss-of-function aspartate-mutants cause altered PS complex maturation, and argue that the functional presenilin moieties are contained in the high molecular weight presenilin NTF/CTF-containing complexes.

Deposition of beta-amyloid subtypes 40 and 42 differentiates dementia with Lewy bodies from Alzheimer disease.

BACKGROUND: Alterations in the metabolism of the amyloid precursor protein and the formation of beta-amyloid (Abeta) plaques are associated with neuronal death in Alzheimer disease (AD). The plaque subtype Abeta(x-42) occurs as an early event, with Abeta(x-40) plaques forming at a later stage. In dementia with Lewy bodies (DLB), an increase in the amount of cortical Abeta occurs without severe cortical neuronal losses. OBJECTIVE: To advance our understanding of the natural history of Abeta in neurodegenerative diseases. DESIGN: We evaluated the expression of Abeta(x-40) and Abeta(x-42) in DLB using monoclonal antibodies and immunohistochemical techniques in 5 brain regions. The data were compared with those elicited with normal aging and from patients with AD. SETTING AND PATIENTS: A postmortem study involving 19 patients with DLB without concurrent neuritic degeneration, 10 patients with AD, and 17 aged persons without dementia for control subjects. RESULTS: The Abeta plaques were more numerous in patients with DLB than in controls in most brain regions, although the Abeta(x-42) plaque subtype was predominant in both conditions. Overall, Abeta(x-42) plaque density was similar in patients with DLB and those with AD, but Abeta(x-40) plaques were more numerous in persons with AD than in those with DLB. The ratio of Abeta(x-40) to Abeta(x-42) plaques was significantly reduced in persons with DLB compared with patients with AD. CONCLUSIONS: The Abeta plaques were more numerous in patients with DLB than persons with normal aging, but the plaque subtypes were similar. The relative proportion of the 2 Abeta plaque subtypes in DLB is distinguishable from that in AD.

Lewy body in neurodegeneration with brain iron accumulation type 1 is immunoreactive for alpha-synuclein.

In familial PD, a mutation of the alpha-synuclein gene has been identified. Alpha-synuclein also was revealed in Lewy bodies in idiopathic PD. Lewy bodies in neurodegeneration with brain iron accumulation type 1 (NBIA 1; Hallervorden-Spatz syndrome) were found to show immunostaining for alpha-synuclein/precursor of non-A beta component of Alzheimer's disease amyloid, indicating that alpha-synuclein is commonly associated with the formation of Lewy bodies in other sporadic and familial neurodegenerative diseases apart from PD.

The tau mutation (val337met) disrupts cytoskeletal networks of microtubules.

The missense point mutation found in the tau gene, which was segregated in a family with frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17), has proved to be the causal molecule for widely spread dementia diseases. Here we examined the effects of the tau mutation using confocal analysis. When wild-type tau cDNA was introduced into cells, extensive cell processes and well-developed thick bundles of microtubules were induced. On the other hand, when altered tau cDNA with the mutation (valine337-methionine) was introduced, cell lost processes and microtubule networks resulted in more round cell shape but showed intact mitochondria or endoplasmic reticulum. We conclude that the tau mutation primarily affects the microtubules and resultantly causes the loss of cellular organization and function due to microtubule disruption.

Mutation of the conserved N-terminal cysteine (Cys92) of human presenilin 1 causes increased A beta42 secretion in mammalian cells but impaired Notch/lin-12 signalling in C. elegans.

The presenilin proteins are involved in the proteolytic processing of transmembrane proteins such as Notch/lin-12 and the beta-amyloid precursor protein (betaAPP). Mutation of a conserved cysteine (Cys60Ser) in the C. elegans presenilin sel-12 has a loss-of-function effect on Notch/lin-12 processing similar to that of null mutations in sel-12. In contrast, in mammalian cells, most missense mutations increase gamma-secretase cleavage of betaAPP. We report here that mutation of this conserved cysteine (Cys92Ser) in human presenilin 1 confers a loss-of-function effect in C. elegans, but causes increased A beta42 secretion in mammalian cells. These data suggest that the role of presenilins in Notch/lin-12 signalling and betaAPP processing are either separately regulated activities or independent activities of the presenilins.

A novel autoantibody in paraneoplastic sensory-dominant neuropathy reacts with brain-type creatine kinase.

We have previously reported on a novel autoantibody in a patient with paraneoplastic sensory-dominant neuropathy. This autoantibody immunostains the rat primary sensory system and reacts with a 47 kDa protein on immunoblotting. Here, we report on the isolation from rat spinal cord of a molecule that is recognized by this autoantibody. By ammonium sulfate cut and gel filtration, affinity and ion exchange chromatographies, the immunoreactive protein was purified to homogeneity and identified as brain-type creatine kinase (B-CK). Our study revealed that the autoantibody of the patient reacted with B-CK in the primary sensory system.

Mutation of conserved aspartates affects maturation of both aspartate mutant and endogenous presenilin 1 and presenilin 2 complexes.

Presenilin (PS1 and PS2) holoproteins are transiently incorporated into low molecular weight (MW) complexes. During subsequent incorporation into a higher MW complex, they undergo endoproteolysis to generate stable N- and C-terminal fragments. Mutation of either of two conserved aspartate residues in transmembrane domains inhibits both presenilin-endoproteolysis and the proteolytic processing of beta-amyloid precursor protein and Notch. We show that although PS1/PS2 endoproteolysis is not required for inclusion into the higher MW N- and C-terminal fragment-containing complex, aspartate mutant holoprotein presenilins are not incorporated into the high MW complexes. Aspartate mutant presenilin holoproteins also preclude entry of endogenous wild type PS1/PS2 into the high MW complexes but do not affect the incorporation of wild type holoproteins into lower MW holoprotein complexes. These data suggest that the loss of function effects of the aspartate mutants result in altered PS complex maturation and argue that the functional presenilin moieties are contained in the high molecular weight complexes.

A founder mutation in presenilin 1 causing early-onset Alzheimer disease in unrelated Caribbean Hispanic families.

CONTEXT: Genetic determinants of Alzheimer disease (AD) have not been comprehensively examined in Caribbean Hispanics, a population in the United States in whom the frequency of AD is higher compared with non-Hispanic whites. OBJECTIVE: To identify variant alleles in genes related to familial early-onset AD among Caribbean Hispanics. DESIGN AND SETTING: Family-based case series conducted in 1998-2001 at an AD research center in New York, NY, and clinics in the Dominican Republic. PATIENTS: Among 206 Caribbean Hispanic families with 2 or more living members with AD who were identified, 19 (9.2%) had at least 1 individual with onset of AD before the age of 55 years. MAIN OUTCOME MEASURE: The entire coding region of the presenilin 1 gene and exons 16 and 17 of the amyloid precursor protein gene were sequenced in probands from the 19 families and their living relatives. RESULTS: A G-to-C nucleotide change resulting in a glycine-alanine amino acid substitution at codon 206 (Gly206Ala) in exon 7 of presenilin 1 was observed in 23 individuals from 8 (42%) of the 19 families. A Caribbean Hispanic individual with the Gly206Ala mutation and early-onset familial disease was also found by sequencing the corresponding genes of 319 unrelated individuals in New York City. The Gly206Ala mutation was not found in public genetic databases but was reported in 5 individuals from 4 Hispanic families with AD referred for genetic testing. None of the members of these families were related to one another, yet all carriers of the Gly206Ala mutation tested shared a variant allele at 2 nearby microsatellite polymorphisms, indicating a common ancestor. No mutations were found in the amyloid precursor protein gene. CONCLUSIONS: The Gly206Ala mutation was found in 8 of 19 unrelated Caribbean Hispanic families with early-onset familial AD. This genetic change may be a prevalent cause of early-onset familial AD in the Caribbean Hispanic population.

Nicastrin modulates presenilin-mediated notch/glp-1 signal transduction and betaAPP processing.

Nicastrin, a transmembrane glycoprotein, forms high molecular weight complexes with presenilin 1 and presenilin 2. Suppression of nicastrin expression in Caenorhabditis elegans embryos induces a subset of notch/glp-1 phenotypes similar to those induced by simultaneous null mutations in both presenilin homologues of C. elegans (sel-12 and hop-1). Nicastrin also binds carboxy-terminal derivatives of beta-amyloid precursor protein (betaAPP), and modulates the production of the amyloid beta-peptide (A beta) from these derivatives. Missense mutations in a conserved hydrophilic domain of nicastrin increase A beta42 and A beta40 peptide secretion. Deletions in this domain inhibit A beta production. Nicastrin and presenilins are therefore likely to be functional components of a multimeric complex necessary for the intramembranous proteolysis of proteins such as Notch/GLP-1 and betaAPP.