Maria Bosch

Dogs with Cognitive Dysfunction Syndrome: A Natural Model of Alzheimer’s Disease

In the search for appropriate models for Alzheimers disease (AD) involving animals other than rodents, several laboratories are working with animals that naturally develop cognitive dysfunction. Among the animals tested, dogs are quite unique in helping to elucidate the cascade of events that take place in brain amyloid-beta (Aβ)deposition aging, and cognitive deficit. Recent innovative research has validated human methods and tools for the analysis of canine neuropathology and has allowed the development of two different approaches to investigate dogs as natural models of AD. The first approach relates AD-like neuropathy with the decline in memory and learning ability in aged housed dogs in a highly controlled laboratory environment. The second approach involves research in family-owned animals with cognitive dysfunction syndrome. In this review, we compare the strengths and limitations of housed and family-owned canine models, and appraise their usefulness for deciphering the early mechanisms of AD and developing innovative therapies.

Reproductive biology, genetic variation and conservation of the rare endemic dysploid Delphinium bolosii (Ranunculaceae)

Abstract Delphinium bolosii C. Blanche and Molero (Ranunculaceae), is a very rare endemic plant known from only two populations in Catalonia, having fewer than 1500 individuals. A biological survey of this species included: (a) reproductive biology, comprising pollination ecology, breeding systems, seed set and pollen viability; and (b) enzyme electrophoresis to measure genetic variation within and between two populations. A trend to increasing self-pollination rates (up to 20%) and to low levels of genetic variation (1.6–1.7 alleles per locus), together with high rates of nectar robber visits are reported. The hypothetic evolutionary relationships (chromosomal changes and geographic isolation) of this species with its related widespread ancestor Delphinium fissum are also discussed. The main threats to this species are catastrophic events (especially as soil erosion), human impact activities (both agriculture and tourism) and decreasing pollination. The small populations and low genetic variation reinforce its endangered status. Some conservation measures are suggested, including in-situ and ex-situ strategies.

Conservation biology of the Pyrenean larkspur (Delphinium montanum): a case of conflict of plant versus animal conservation?

Abstract Delphinium montanum is a larkspur endemic to the Pyrenees. It has c. 4000 individuals and is classified as vulnerable following the IUCN categories. Pollination ecology results demonstrated that it is strictly dependent on pollinator activity (mainly bumblebees) to set seeds. Genetic diversity estimated by allozyme variation at 7 loci showed quite high levels of variation related to its polyploidy. Predation by Pyrenean chamois ( Rupicapra rupicapra pyrenaica ), first detected in 1993, caused a continuous loss of >90% of seed set in a protected area. The maintenance of high genetic diversity suggests the buffer effect of polyploidy and seed bank strategy to counter animal grazing, but long-term effects on conservation are expected. These results stressed: (1) the need for a plan to monitor this animal–plant interaction; and (2) the need to monitor closely the population number of individuals of certain protected animal species in Natural Reserves, particularly if ecological competition has been disturbed by human intervention.

Breeding systems in tribe Delphinieae (Ranunculaceae) in the western Mediterranean area

Summary The breeding system of 30 populations belonging to 20 species of Aconitum, Delphinium and Consolida ( Delphinieae, Ranunculaceae) in the western Mediterranean area was studied and its relation with life-span and systematic position is discussed. To assess the breeding system we measured seed set in response to different pollination treatments. We performed greenhouse tests for agamospermy, spontaneous self-pollination, induced self-pollination, geitonogamy, cross-pollination and, in some cases, insect exclusion tests in the field. Morphological characters like stamen number, pollen production, ovule production and pollen: ovule ratio (P/O) were quantified. Most species are facultative xenogamous and partially self-compatible. P/O ratios were rather consistent with the observed xenogamy, although there is no relation between P/O values and selfing rates. P/O ratio was positively correlated with seed weight, but is heavily influenced by one species. A trend towards increased autogamy in annuals, especially in subgenus Staphisagria, was detected. In these taxa xenogamy and insect pollination are evolutionary primitive, and autogamy is derived. Similar reproductive patterns in closely related taxa suggest that only slight differentiation occurred after primary strain diversification of this group.

Population genetics and conservation priorities for the critically endangered island endemic Delphinium pentagynum subsp. formenteranum (Ranunculaceae)

Isozyme electrophoresis was used to evaluate levels of genetic diversity and population genetic structure of the critically endangered (CR) perennial larkspur, Delphinium pentagynum subsp. formenteranum (Ranunculaceae), endemic to the island of Formentera (Balearic Islands, Spain). There is only one known population for this taxon, containing only 480 individuals. Moderate values of diversity were detected (P = 40.7%, A = 1.6 and He = 0.180), within the range observed in other surveyed larkspurs, but higher than most island endemics. Moderate levels of inbreeding were detected, probably as a consequence of the populations genetic structuring (biparental inbreeding). Threats to this taxon are mainly anthropogenic (fires, grazing, pathway works, and building pressures), although given that only one population exists, stochastic risks cannot be ignored. Conservation of D. pentagynum subsp. formenteranum requires in situ strategies, such as implementing a monitoring program and establishing a ‘botanical reserve’, and ex situ strategies, such as collection and long-term storage of seeds.

Rapid improvement of canine cognitive dysfunction with immunotherapy designed for Alzheimer's disease.

Immunotherapy against amyloid-β(Aβ) may improve rodent cognitive function by reducing amyloid neuropathology and is being validated in clinical trials with positive preliminary results. However, for a complete understanding of the direct and long-term immunization responses in the aged patient, and also to avoid significant side effects, several key aspects remain to be clarified. Thus, to investigate brain Aβ clearance and Th2 responses in the elderly, and the reverse inflammatory events not found in the immunized rodent, better Alzheimers disease (AD) models are required. In the aged familiar canine with a Cognitive Dysfunction Syndrome (CDS) we describe the rapid effectiveness and the full safety profile of a new active vaccine candidate for human AD prevention and treatment. In these aged animals, besidesa weak immune system, the antibody response activated a coordinated central and peripheral Aβ clearance, that rapidly improved their cognitive function in absence of any side effects. Our results also confirm the interest to use familiar dogs to develop innovative and reliable therapies for AD.

Genetic Diversity Within and among Disjunct Populations of the Mediterranean Island Endemic Delphinium pictum and D. requienii (Ranunculaceae)

Allozyme diversity was assessed in 13 populations of Delphinium pictum and D. requienii, two short-lived and closely related insular Mediterranean endemics. While D. pictum has scattered distribution in Corsica, Sardinia and Majorca, D. requienii is found in a few small populations restricted to the Hyères Archipelago. Eleven enzyme systems were assayed, and 15 loci were resolved. Both species harboured moderate levels of genetic diversity, comparable to the values expected for endemic plants. All genetic parameters suggested higher diversity in D. pictum (A = 1.93, P = 40, He = 0.106) than in D. requienii (A = 1.30, P = 26.7, He = 0.096); FIS values revealed higher inbreeding in D. requienii. Although the two species did not harbour species-specific alelles in the surveyed loci, the UPGMA dendrogram based on Nei’s genetic similarity index supported divergence between them. These results, together with significant morphological similarity and evidence of successful hybridization between the species, support the hypothesis of a recent speciation event. The moderate levels of both genetic variability and population divergence observed for D. pictum are likely attributable to its ability to establish seed banks. Given that the allozyme variation detected for D. pictum was significantly partitioned among islands, we suggest the implementation of conservation programs throughout its distribution range, and not only in Corsica as it occurs nowadays. Management strategies are also desirable for D. requienii to maintain population size and control inbreeding.

Amyloid-β immunotherapy reduces amyloid plaques and astroglial reaction in aged domestic dogs.

Background: Alzheimers disease (AD) is characterized by the dynamic accumulation of extracellular amyloid deposits from the interplay between amyloid-β (Aβ) plaques, reactive astrocytes and activated microglia. Several immunotherapies against Aβ have been shown to reduce amyloid neuropathology. However, the role of the associated glia in the recovery process requires clarification. Previously, we described the safety and effectiveness in aged domestic canine with cognitive dysfunction syndrome of a new active vaccine candidate for the treatment of AD in humans. Objective: The aim of this article is to gain a better understanding of how immunotherapy modifies the amyloid burden and its effects on astroglial and microglial reactivity in immunized dogs. Methods: In order to achieve this, we compared and quantified amyloid plaques and astroglial and microglial reactions in the frontal cortex of unimmunized and immunized aged domestic dogs. Results: We found amyloid plaques from immunized dogs to be smaller and more compact than those from unimmunized dogs. In these new plaques, the associated astrocytes were closer and less immunoreactive to the β subunit of S100 protein (S100B). We also found no modification in the microglial reaction associated with immunization. Conclusion: The anti-Aβ immunotherapy developed in our laboratory modifies the equilibrium between soluble and insoluble Aβ in aged dogs in close correlation with S100B-negative astrocytosis and microglial reaction.

Shift towards autogamy in the extremely narrow endemic Aquilegia paui and comparison with its widespread close relative A. vulgaris (Ranunculaceae)

Aquilegia paui is an extremely narrowly endemic species from the northeastern Iberian Peninsula. It is restricted to a few populations with a reduced number of individuals living in summit rock cliffs. It is studied and compared to the widespread Aquilegia vulgaris to assess differences in their breeding system and pollination ecology, expected by their differences in flower morphology and by their habitat divergence. Pollinator exclusion experiments showed the capacity of A. paui to reach a full seed set in the absence of pollinators, whereas A. vulgaris notably reduced its reproductive success under these conditions. At the same time, no insect visits were detected in A. paui, whereas A. vulgaris was frequently visited, mainly by bumblebees and flies. Thus, an evolutionary shift toward autogamy in A. paui is discussed in relation to enhanced reproductive assurance. Additionally, we address reproductive isolation mechanisms that nowadays keep A. paui and A. vulgaris separated in spite of their ability to intercross and the existence of contact areas.

Conservation Genetics of Dichoropetalum schottii (Apiaceae): Is the Legal Protection of Edge Populations Consistent with the Genetic Data?

Dichoropetalum schottii is a species that lives at low to medium altitudes in the southern European mountain ranges, from the Balkans (N Greece) to the Pyrenees. Its legal protection status is not homogeneous along its distribution range, as only some of its edge populations, in the Pyrenees, are protected. Here, by means of allozyme electrophoresis, we examine the genetic variability of populations representing four different regions within its distribution area (Pyrenees, Maritime Alps, Karst Plateau in the SW Slovenia—NE Italy border region, and Pindus Mountains in Greece). The species as a whole exhibits relatively high levels of genetic diversity, partly due to the occurrence of several duplications among the loci surveyed. Genetic differentiation among populations and regions was low, which could be interpreted as the result of recent allopatric fragmentation. We conclude that the species as a whole is not threatened, and that the currently protected populations are, paradoxically, the least valuable from the genetic point of view.