Evaluation of the Feasibility, Safety and Efficacy of the Use of Intravenous Infusions of Adenosine Triphosphate (ATP) in People Affected by Moderate to Severe Alzheimer's Disease: A Double-Blind Masked Clinical Trial for Dose Finding

BACKGROUND

There are currently no drug therapies modifying the natural history of patients suffering Alzheimer's disease (AD). Most recent clinical trials in the field include only subjects in early stage of the disease, while patients with advanced AD are usually not represented.

OBJECTIVES

To evaluate the feasibility, safety and efficacy of systemic infusions of adenosine triphosphate (ATP) in patients with moderate to severe AD, and to select the minimum effective dose of infusion.

DESIGN

A phase IIb, randomized, double-blind, placebo-controlled clinical trial investigates.

PARTICIPANTS

A total of 20 subjects with moderate or severe AD were included, 16 in the treatment group and 4 in the placebo group (4:1 randomization) at two dosage regimens, 6-hour or 24-hour infusions.

RESULTS

The proof-of-concept study was successfully conducted, with no significant deviations from the study protocol and no serious adverse events reported. Regarding efficacy, only marginal differences were observed between ATP and placebo arms for H-MRS and MMSE variables.

CONCLUSIONS

Our study demonstrates that the use of ATP infusion as therapy is feasible and safe. Larger studies are however needed to assess the efficacy of ATP in moderate to severe AD.

PLCG2 protective variant p.P522R modulates tau pathology and disease progression in patients with mild cognitive impairment

A rare coding variant (rs72824905, p.P522R) conferring protection against Alzheimer’s disease (AD) was identified in the gene encoding the enzyme phospholipase-C-γ2 (PLCG2) that is highly expressed in microglia. To explore the protective nature of this variant, we employed latent process linear mixed models to examine the association of p.P522R with longitudinal cognitive decline in 3595 MCI patients, and in 10,097 individuals from population-based studies. Furthermore, association with CSF levels of pTau₁₈₁, total tau, and Aβ_1-42 was assessed in 1261 MCI patients. We found that MCI patients who carried the p.P522R variant showed a slower rate of cognitive decline compared to non-carriers and that this effect was mediated by lower pTau₁₈₁ levels in CSF. The effect size of the association of p.P522R with the cognitive decline and pTau₁₈₁ was similar to that of APOE-ε4, the strongest genetic risk factor for AD. Interestingly, the protective effect of p.P522R was more pronounced in MCI patients with low Aβ_1-42 levels suggesting a role of PLCG2 in the response to amyloid pathology. In line with this hypothesis, we observed no protective effect of the PLCG2 variant on the cognitive decline in population-based studies probably due to the lower prevalence of amyloid positivity in these samples compared to MCI patients. Concerning the potential biological underpinnings, we identified a network of co-expressed proteins connecting PLCG2 to APOE and TREM2 using unsupervised co-regulatory network analysis. The network was highly enriched for the complement cascade and genes differentially expressed in disease-associated microglia. Our data show that p.P522R in PLCG2 reduces AD disease progression by mitigating tau pathology in the presence of amyloid pathology and, as a consequence, maintains cognitive function. Targeting the enzyme PLCG2 might provide a new therapeutic approach for treating AD.

Genome Wide Meta-Analysis identifies common genetic signatures shared by heart function and Alzheimer's disease

Echocardiography has become an indispensable tool for the study of heart performance, improving the monitoring of individuals with cardiac diseases. Diverse genetic factors associated with echocardiographic measures have been previously reported. The impact of several apoptotic genes in heart development identified in experimental models prompted us to assess their potential association with human cardiac function. This study aimed at investigating the possible association of variants of apoptotic genes with echocardiographic traits and to identify new genetic markers associated with cardiac function. Genome wide data from different studies were obtained from public repositories. After quality control and imputation, a meta-analysis of individual association study results was performed. Our results confirmed the role of caspases and other apoptosis related genes with cardiac phenotypes. Moreover, enrichment analysis showed an over-representation of genes, including some apoptotic regulators, associated with Alzheimer's disease. We further explored this unexpected observation which was confirmed by genetic correlation analyses. Our findings show the association of apoptotic gene variants with echocardiographic indicators of heart function and reveal a novel potential genetic link between echocardiographic measures in healthy populations and cognitive decline later on in life. These findings may have important implications for preventative strategies combating Alzheimer's disease.

Specific haplotypes of the CALPAIN-5 gene are associated with polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common endocrine disorder in women of reproductive age. The aim of the present study was to investigate the role of CALPAIN-5 (CAPN5) gene in PCOS susceptibility.

METHODS

We analysed four intronic polymorphisms of the CAPN5 gene in 148 well-characterized women with PCOS and 606 unrelated controls. We performed a case-control study and an intracohort analysis of clinical characteristics associated with PCOS.

RESULTS

Analysis of haplotypes distribution between PCOS population compared to controls showed a strong deviation (P = 0.00029). The haplotypes GGCA and GGTG were overrepresented in PCOS patients (P = 0.009 and P = 0.001, respectively). In addition, we identified several CAPN5 haplotypes associated with phenotypic differences observed between PCOS patients, such as the presence of obesity (P = 0.02), cardiovascular complications (P = 0.02), familial antecedents of obesity (P = 0.003) and of hypertension (P = 0.007) and type 2 diabetes mellitus aggregation (P = 0.04).

CONCLUSIONS

These results suggest a role of CAPN5 gene in PCOS susceptibility in humans. Moreover, novel candidate risk alleles have been identified, within CAPN5 gene, which could be associated with important phenotypic and prognosis differences observed in PCOS patients.

Specific polymorphisms in the RET proto-oncogene are over-represented in patients with Hirschsprung disease and may represent loci modifying phenotypic expression

Hirschsprung disease (HSCR) is a common genetic disorder presenting with functional intestinal obstruction secondary to enteric aganglionosis. HSCR can be familial or sporadic. Although five putative susceptibility genes have been identified, only germline mutations in the RET proto-oncogene account for a significant minority (up to 50%) of familial HSCR; 3% of sporadic HSCR in a population based series carry RET mutations. From 1998 to February 1999, we prospectively ascertained 64 cases of sporadic HSCR from the western Andalusia region. To determine if polymorphic sequence variants within RET could act as low penetrance predisposing alleles, we examined allelic frequencies at seven polymorphic loci in this population based series. Whether allele frequencies differed from those in the control population were determined by either chi-squared analysis or Fisher's exact test. For two sequence variants, A45A (c 135G-->A) (exon 2) and L769L (c 2307T-->G) (exon 13), the rarer polymorphic allele was over-represented among HSCR cases versus controls (p<0.0006). In contrast, two other polymorphisms, G691S (c 2071C-->A) (exon 11) and S904S (c 2712C-->G) (exon 15), were under-represented in the HSCR patients compared to controls (p=0.02). Polymorphisms in the RET proto-oncogene appear to predispose to HSCR in a complex, low penetrance fashion and may also modify phenotypic expression.

High prevalence of the C634Y mutation in the RET proto-oncogene in MEN 2A families in Spain

The RET proto-oncogene encodes a receptor tyrosine kinase expressed in neural crest derived tissues. Germline mutations in the RET proto-oncogene are responsible for three different dominantly inherited cancer syndromes: multiple endocrine neoplasia type 2A (MEN 2A), type 2B (MEN 2B), and familial medullary thyroid carcinoma (FMTC). MTC can also occur sporadically. Molecular characterisation of the RET proto-oncogene has been performed by PCR-SSCP analysis, direct DNA sequencing, and restriction enzyme analysis in 49 unrelated, Spanish, MEN 2 families: 30 MEN 2A families, six FMTC families, and 13 families classified as "other". Germline missense mutations in one of six cysteine codons (609, 611, 618, and 620 in exon 10, and codons 630 and 634 in exon 11), which encode part of the extracellular cysteine rich domain of RET, have been detected in the majority of these families: 100% of MEN 2A families, 67% of FMTC families, and 54% of families classified as "other". No RET mutations in exons 10, 11, 13, 14, 15, or 16 were detected in the remaining families. The most frequent RET mutation in MEN 2A Spanish families is C634Y, occurring in 73% of cases. Haplotype analysis does not exclude the possibility of founder effects in Spanish MEN 2A families with the C634Y mutation.

Molecular analysis of the ret and GDNF genes in a family with multiple endocrine neoplasia type 2A and Hirschsprung disease

The clinical association between multiple endocrine neoplasia type 2 (MEN2) and Hirschsprung disease (HSCR) is infrequent. Germline mutations of the ret protooncogene are the underlying cause of the MEN2 syndromes and a proportion of cases of HSCR. In this report, we describe a new kindred in which the MEN2 and HSCR phenotypes are associated with a single C620S point mutation at one of the cysteine codons of the extracellular domain of the ret protooncogene. We also speculate about the role of a silent mutation in exon 2 of this same gene (A45A), present in a homozygous state in the patient with both MEN2A and HSCR. To investigate the contribution of GDNF to the phenotype observed in this kindred, we scanned the coding region of GDNF in the patient with MEN2/HSCR, but no mutation was found.