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therefore lead to future developments of new therapeutic drugs forskin regeneration.

doi:10.1016/j.toxlet.2012.03.181

44 Abstracts / Toxicology L

02-04onclinical safety assessment of the RANK-L targetinganobody® ALX-0141

andy Jacobs∗MaartenVan Roy, Alex Hemeryck, Ingrid Ottevaere,udith Baumeister

Ablynx nv, Belgium

Nanobodies are therapeutic proteins based on the smallest func-ional fragments of naturally occurring heavy-chain antibodies andeveloped for a wide variety of indications. Due to high format-ing flexibility of Nanobodies, designing toxicity packages requirescase-by-case science-based approach. The lack of an Fc region

nd high specificity are expected to translate into a favorable safetyrofile.

ALX-0141 targets RANK-L and inhibits osteoclast differenti-tion, activation and survival. It binds to serum albumin via apecific moiety, which confers a favorable half-life. Cynomol-us monkey was identified as only relevant species based onarget-binding and demonstrated in vitro and in vivo pharma-ology. Dedicated efficacy and pharmacokinetic studies showedhat ALX-0141 has a favorable half-life in cynomolgus monkey.harmacokinetic/pharmacodynamic information was used to buildertinent models, which were employed to predict exposures inoxicity studies and simulate dosing regimens and recovery peri-ds.

The toxicity package consisted of a single dose, a 2-week and26-week repeated dose study in cynomolgus monkey, including

ocal tolerance and safety pharmacology.Markers for bone resorption and formation like CTx-1 and P1NP

ere suppressed during treatment in all dose groups and showedeturn to baseline during recovery. Bone densitometry testingDXA and pQCT) demonstrated an increase in bone mass, mostronounced in male animals. Exaggerated pharmacology was rec-gnized as muscle spasms as clinical presentation of hypocalcemian rare cases and dose-independent. ALX-0141 was proven to be

ell-tolerated during long-term repeated dosing up to 100 mg/kg,nce every 2 weeks, which translated into an excellent clinicalafety profile.

oi:10.1016/j.toxlet.2012.03.179

02-05llele frequencies of fifteen STR loci in a population sample

rom Crete

lena Vakonaki 1, Maria Christakis-Hampsas 2, Athanasioslegakis 2, Matthaios Flamourakis 3, Leda Kovatsi 4, Elisavetenieri 2, Christina Tsitsimpikou 5, Stamatis Belivanis 2, Aristidissatsakis 2

University of Crete, Medical School, Greece, 2 University of Crete,reece, 3 St. Savvas Anticancer Hospital of Athens, Greece, 4 Aristotleniversity of Thessaloniki, Greece, 5 General Chemical Stateaboratory, Greece

Purpose: To investigate the genetic polymorphisms of 15 shortandem repeats (STRs) loci, in particular D8S1179, D21S1, D7S820,SF1PO, D3S1358, TH01, D13S317, D16S539, vWA, TPOX, D18S51,5S818, Penta E, Penta D and FGA, in a native Cretan population.

Methods: One hundred (100) blood or buccal swab samplesere randomly selected from the paternity database of the Tox-

cology Laboratory, University of Crete. All samples were selectedrom unrelated persons who originate from different provinces of

211S (2012) S43–S216

Crete. DNA was extracted by using the Quick-gDNA Microprep kit.PCR amplification was performed by PowerPlex 16® Promega. Theamplification products were separated on an ABI 3500, GeneticAnalyzer.

Results and conclusions: Frequencies at each locus were calcu-lated by direct counting. There were noticeable differences withother European populations at the TPOX locus, with the most fre-quent allele being allele 8 (0.5). Other frequent alleles includedallele 12 (0.36) at the D5S818 locus, allele 11 (0.34) at the D16S539locus, allele 11 (0.33) at the CSF1PO locus, and allele 12 (0.33) at theD13S317 locus. Estimations of Hardy–Weinberg equilibrium wereconducted and no deviations were detected (p > 0.05). The 15 lociincluded in the kit offer a highly discriminating system for use inpaternity and forensic casework. No differences with other Greekpopulations were detected. On the other hand, significant differ-ences in the frequency of specific alleles were observed, comparedto other populations.

doi:10.1016/j.toxlet.2012.03.180

P02-06Beneficial effects of mesenchymal stem cells conditionedmedia on skin regeneration

Joana Miranda 1, Elysse Filipe 1, Rita Barcia 2, Helder Cruz 2, PedroCruz 2, Ana Sofia Fernandes 1, Madalena Cipriano 1, MatildeCastro 1, Miguel Santos 2

1 iMed-UL, Fac of Pharmacy-Univ Lisbon, Portugal, 2 ECBio S.A.,Portugal

Increasing evidence supports that mesenchymal stem cells(MSCs) play a role in tissue regeneration mainly through thesecretion of soluble trophic factors. Such factors may assist inthe regeneration of damaged tissue by promoting angiogenesis,immune-modulation, paracrine activation of surrounding precur-sor cells, or most likely by a complex combination of all thesemechanisms. This work aims to evaluate the therapeutic value ofconditioned media (CM) prepared from culturing MSCs from differ-ent sources, and at different growth stages, on cellular migrationand cutaneous wound regeneration.

An in vitro migrational scratch assay on human dermal fibrob-lasts and keratinocytes; and an in vivo wound-healing assay using amouse model were performed. CM at 0% and 2% FBS were preparedunder different culture conditions, namely confluent or growingumbilical cord matrix derived MSCs (ucmMSCs), and growing bonemarrow derived MSCs (bmMSC), and applied to the experimen-tal models abovementioned. The beneficial effect of MSC CM wasassessed and a comparison between ucmMSCs and bmMSCs CMwas performed.

Overall, the results showed that all MSC-derived CM enhancedcellular migration when compared to the control. Moreover, grow-ing MSCs secreted a richer trophic factor profile which translatedto an enhanced cellular migration capacity and wound healingeffectiveness in vivo. Thus, this work suggests that trophic factorssecreted by MSCs may indeed be beneficial to skin regeneration indifferent pathological or toxicological contexts. The identificationof the key components in skin regeneration secreted by MSCs may