SIUrO best practice recommendations to optimize BRCA 1/2 gene testing from DNA extracted from bone biopsy in mCRPC patients (BRCA Optimal Bone Biopsy Procedure: BOP)

The main guidelines and recommendations for the implementation of the BRCA1/2 somatic test do not focus on the clinical application of predictive testing on bone metastases, a frequent condition in metastatic prostate cancer, by analyzing the critical issues encountered by laboratory practice. Our goal is to produce a document (protocol) deriving from a multidisciplinary team approach to obtain high quality nucleic acids from biopsy of bone metastases. This document aims to compose an operational check-list of three phases: the pre-analytical phase concerns tumor cellularity, tissue processing, sample preservation (blood/FFPE), fixation and staining, but above all the decalcification process, the most critical phase because of its key role in allowing the extraction of somatic DNA with a good yield and high quality. The analytical phase involves the preparation of the libraries that can be analyzed in various NGS genetic sequencing platforms and with various bioinformatics software for the interpretation of sequence variants. Finally, the post-analytical phase that allows to report the variants of the BRCA1/2 genes in a clear and usable way to the clinician who will use these data to manage cancer therapy with PARP Inhibitors.

Remote vs in-person BRCA1/2 non-carriers test disclosure: patients' choice during Covid-19 pandemic restriction

During Covid-19 pandemic most hospitals have restricted in-person delivery of non-essential healthcare services, including genetic testing delivery, to slow the spread of the virus. Our Onco-Genetic Service also faced this challenging period and had to re-organize its clinical practice with the use of tele-health. Aim of the present paper is to understand whether and how Covid-19-related changes in medical practice influenced patients' satisfaction about the health service provided. 125 BRCA1/2 non carriers (109/125, 87.2% female and 16/125, 12.8% male) in Istituto Tumori "Giovanni Paolo II" of Bari were enrolled. All participants were asked to choose whether they prefer in-person or remote post-test counselling session. Basing on patients' choice, two groups of subjects were composed. One week after the post-test counselling session, participants were phone called and asked to complete: a socio-demographic form, a brief structured interview about their Covid-19 related worries and their satisfaction with the health service provided, Hospital Anxiety and Depression Scale and Fear of Covid-19 scale. Qualitative information about patients' choice were also collected. No significant difference about patients' satisfaction with the health service provided emerged between groups. Patients who preferred remote post-test counselling had higher anxiety, worries and fear-of Covid-19 than the others. All remote-counselling subjects preferred tele-genetics because of Covid-19 security, would choose it again and would recommend it to others. Cancer tele-genetics offers good guarantees of comfort and efficacy, but patients' choices are related to personal and psychological variables. The use of tele-genetics has to be a patient's choice.

P-098 Male age does not affect sperm motility rate after thawing and laboratory outcomes of transnational oocyte donation programs

Study question

Can outcomes of transnational egg donation treatments, which involves the shipping of cryopreserved partner semen, be affected by advanced paternal age?

Summary answer

Male age does not affect percentage of motile spermatozoa after thawing. Advanced paternal age does not affect IVF laboratory outcomes of transnational egg donation treatments

What is known already

Studies on advanced paternal age are limited and a clear definition of advanced paternal age is still missing. The separation between advanced paternal and maternal age effects is hampered by the collinearity of maternal age with paternal age, since older males are often associated with older women. Many studies have focused on egg donation treatments, to overcome this problem. However, these studies reported conflicting results, such as a putative effect of advanced paternal age on ICSI outcomes, while some others not. This study analyzes paternal age in transnational egg donation program, which involves the shipping of cryopreserved partner semen

Study design, size, duration

A multicentric retrospective cohort study involving 101 couples and 327 blastocysts was performed from June 2018 up to December 2021. Two Italian IVF centers involved a Spanish center to perform a transnational fresh oocyte donation program. The aim of the study was to analyze the putative effect of male age on (i) semen parameters, (ii) fertilization rate and (iii) blastocyst rate.

Participants/materials, setting, methods

Donations of both male and female gametes were excluded. We performed sperm cryopreservation of the male partner of the recruited couples. Frozen samples were shipped with a authorized courier, which certified the safety of the whole procedure. The day of donor’s egg retrieval, semen samples were thawed and ICSI was performed on fresh donated oocytes. Resulted blastocysts were vitrified and shipped to the centers where the frozen embryo transfers in the recipient patients were performed.

Main results and the role of chance

The mean of male partners age was 42.6 ± 6.5 (min 26- max 63). Overall fertilization rate was 81.6% (686/840), and blastocyst rate was 47.6% (327/686). Male age was analyzed as a continuous variable and divided into five groups calculated for 5-year intervals. No differences in terms of fertilization rates nor blastocysts rates were found (85.3% and 43.7% for <35-years; 84.7% and 54.0% for 36-39-years; 79.7% and 44.2% for 40-44-years; 89.6 and 48.1% for 45-49-years; 74.5% and 56.5 for >50-years). Although advanced paternal age has been correlated to the decrease of most of sperm parameters, in the present study we found that only progressive rapid motility was significantly affected by advanced paternal age (coefficient -0.261 , P = 0.009). To evaluate the predictive value of advanced paternal age and sperm parameters on fertilization and blastocysts formation, we performed a multiple linear regression analysis. We found that sperm parameters and male age in our sample are not predictive of the number of fertilized oocytes nor the number of obtained blastocysts. Importantly for the setting of the study, the percentage of progressive motile sperm at the thawing was not influenced by paternal age.

Limitations, reasons for caution

The main limitation of the study is the small sample size, which might mask the paternal age effect on the sperm parameters, as the volume, which tend to decrease in the classes of age, but did not reached the statistical significance. The multicentric nature of the study represent a strength

Wider implications of the findings

The discomfort for couples that need oocyte donation in countries where there is a low availability of egg donors is often underestimated. This study demonstrate that, independently of male age, the shipping of frozen sperm and the ICSI of freshly donated oocytes represent a valid option for these couples.

Trial registration number

not applicable

Can harmful lifestyle, obesity and weight changes increase the risk of breast cancer in BRCA 1 and BRCA 2 mutation carriers? A Mini review

Background and aim

The BRCA 1 and BRCA 2 genes are associated with an inherited susceptibility to breast cancer with a cumulative risk of 60% in BRCA 1 mutation carriers and of 30% in BRCA 2 mutation carriers. Several lifestyle factors could play a role in determining an individual’s risk of breast cancer. Obesity, changes in body size or unhealthy lifestyle habits such as smoking, alcohol consumption and physical inactivity have been evaluated as possible determinants of breast cancer risk. The aim of this study was to explore the current understanding of the role of harmful lifestyle and obesity or weight change in the development of breast cancer in female carriers of BRCA 1/2 mutations.

Methods

Articles were identified from MEDLINE in October 2020 utilizing related keywords; they were then read and notes, study participants, measures, data analysis and results were used to write this review.

Results

Studies with very large case series have been carried out but only few of them have shown consistent results. Additional research would be beneficial to better determine the actual role and impact of such factors.

Spectrum of Germline Pathogenic Variants in BRCA1/2 Genes in the Apulian Southern Italy Population: Geographic Distribution and Evidence for Targeted Genetic Testing

Simple Summary

BRCA1 and BRCA2 are two major high-penetrance breast/ovarian cancer predisposition genes, whose mutations can lead to high risk and early onset of breast and ovarian cancer. Numerous studies are focused on spectrum and prevalence of BRCA1/2 mutations worldwide. This is the first study that exclusively focused on native Apulian probands. We found that ten recurrent BRCA1/2 pathogenic variants account for more than half of the patients with proven HBOC syndrome from Apulia. Besides BRCA1 c.5266dupC, which is present in significant numbers in every Apulian province, the other PVs occur at a high frequency in some areas and not others. In-depth knowledge of the mutation spectrum of the target population and of the relatively small number of recurrent mutations is crucial to develop a specific cost-effective strategy for mutation screening and a program for breast–ovarian cancer control and prevention through more liberal, yet rational, genetic testing and counseling.

Abstract

BRCA1/2-associated hereditary breast and ovarian cancer is the most common form of hereditary breast and ovarian cancer and occurs in all ethnicities and racial populations. Different BRCA1/BRCA2 pathogenic variants (PVs) have been reported with a wide variety among populations. In this study, we retrospectively analyzed prevalence and geographic distribution of pathogenic germline BRCA1/2 variants in families from Apulia in southern Italy and evaluated the genotype–phenotype correlations. Data were collected from Oncogenetic Services present in Apulian hospitals and a shared database was built containing Apulian native probands (n = 2026) that had undergone genetic testing from 2004 to 2019. PVs were detected in 499 of 2026 (24.6%) probands and 68.5% of them (342 of 499) were in the BRCA1 gene. We found 65 different PVs in BRCA1 and 46 in BRCA2. There were 10 most recurrent PVs and their geographical distribution appears to be significantly specific for each province. We have assumed that these PVs are related to the historical and geopolitical changes that occurred in Apulia over time and/or to a “founder effect”. Broader knowledge of BRCA1/2 prevalence and recurring PVs in specific geographic areas could help establish more flexible genetic testing strategies that may enhance our ability to detect high-risk subjects.

Detection of Germline Variants in 450 Breast/Ovarian Cancer Families with a Multi-Gene Panel Including Coding and Regulatory Regions

With the progress of sequencing technologies, an ever-increasing number of variants of unknown functional and clinical significance (VUS) have been identified in both coding and non-coding regions of the main Breast Cancer (BC) predisposition genes. The aim of this study is to identify a mutational profile of coding and intron-exon junction regions of 12 moderate penetrance genes (ATM, BRIP1, CDH1, CHEK2, NBN, PALB2, PTEN, RAD50, RAD51C, RAD51D, STK11, TP53) in a cohort of 450 Italian patients with Hereditary Breast/Ovarian Cancer Syndrome, wild type for germline mutation in BRCA1/2 genes. The analysis was extended to 5′UTR and 3′UTR of all the genes listed above and to the BRCA1 and BRCA2 known regulatory regions in a subset of 120 patients. The screening was performed through NGS target resequencing on the Illumina platform MiSeq. 8.7% of the patients analyzed is carriers of class 5/4 coding variants in the ATM (3.6%), BRIP1 (1.6%), CHEK2 (1.8%), PALB2 (0.7%), RAD51C (0.4%), RAD51D (0.4%), and TP53 (0.2%) genes, while variants of uncertain pathological significance (VUSs)/class 3 were identified in 9.1% of the samples. In intron-exon junctions and in regulatory regions, variants were detected respectively in 5.1% and in 32.5% of the cases analyzed. The average age of disease onset of 44.4 in non-coding variant carriers is absolutely similar to the average age of disease onset in coding variant carriers for each proband’s group with the same cancer type. Furthermore, there is not a statistically significant difference in the proportion of cases with a tumor onset under age of 40 between the two groups, but the presence of multiple non-coding variants in the same patient may affect the aggressiveness of the tumor and it is worth underlining that 25% of patients with an aggressive tumor are carriers of a PTEN 3′UTR-variant. This data provides initial information on how important it might be to extend mutational screening to the regulatory regions in clinical practice.

Blood Arsenic Levels as a Marker of Breast Cancer Risk among BRCA1 Carriers

An important group of breast cancers is those associated with inherited susceptibility. In women, several predisposing mutations in genes involved in DNA repair have been discovered. Women with a germline pathogenic variant in BRCA1 have a lifetime cancer risk of 70%. As part of a larger prospective study on heavy metals, our aim was to investigate if blood arsenic levels are associated with breast cancer risk among women with inherited BRCA1 mutations. A total of 1084 participants with pathogenic variants in BRCA1 were enrolled in this study. Subjects were followed from 2011 to 2020 (mean follow-up time: 3.75 years). During that time, 90 cancers were diagnosed, including 67 breast and 10 ovarian cancers. The group was stratified into two categories (lower and higher blood As levels), divided at the median (<0.85 µg/L and ≥0.85 µg/L) As level among all unaffected participants. Cox proportional hazards models were used to model the association between As levels and cancer incidence. A high blood As level (≥0.85 µg/L) was associated with a significantly increased risk of developing breast cancer (HR = 2.05; 95%CI: 1.18-3.56; p = 0.01) and of any cancer (HR = 1.73; 95%CI: 1.09-2.74; p = 0.02). These findings suggest a possible role of environmental arsenic in the development of cancers among women with germline pathogenic variants in BRCA1.

Somatic BRCA Mutation in a Cholangiocarcinoma Patient for HBOC Syndrome Detection

BRCA-associated hereditary breast and ovarian cancer syndrome (HBOC) is characterized by an increased risk of developing other malignancies including cholangiocarcinoma (CCA). Somatic BRCA mutations have been reported in CCA, but they have yet to be utilized in a proband case to identify HBOC in families. Two healthy daughters of a deceased female patient who had had metachronous breast cancer and CCA received genetic counseling to assess their cancer risk. Somatic BRCA1/2 mutation analysis was performed by next-generation sequencing on the DNA extracted from a formalin-fixed, paraffin-embedded CCA biopsy specimen of their mother. A pathogenic variant was identified (c.6468_6469delTC in a BRCA2 gene mutation). Germline BRCA mutation analysis of the two daughters detected the same pathogenic variant in one of them. For the first time, a CCA somatic BRCA mutation has been used to identify a family with HBOC.

The Role of Circulating Adiponectin and SNP276G>T at ADIPOQ Gene in BRCA-mutant Women

BACKGROUND

Environmental factors may influence the lifetime risk of cancer (penetrance) in women with a BRCA mutation.

MATERIALS AND METHODS

In 89 BRCA-mutant women, affected or unaffected by breast/ovarian cancer, we explored serum levels of adipokines and their relation with the polymorphism SNP276G>T as modulators of BRCA penetrance.

RESULTS

Affected women had significantly lower adiponectin than healthy women. Affected women with rs1501299 TT had significantly lower adiponectin and higher leptin than GT and GG genotypes. GT genotype was significantly associated with the disease status [odds ratio (OR)=3.24, 95% confidence interval (95% CI)=1.03-10.17]. Women in the lower tertile of serum adiponectin had a RR of BRCA-associated cancer of 2.80, 95% CI=1.1-7.1 (p for trend=0.03) compared with women in the higher tertile.

CONCLUSION

In the SNP rs1501299 the T allele was significantly associated with lower serum levels of adiponectin in affected women, suggesting that the T allele might be related to cancer.

Hyaluronic acid, Manuka honey and Acemannan gel: Wound-specific applications for skin lesions

Healing of open wounds is of great medical importance. Wound healing is a complex process that aims to restore the function and structure of damaged tissue. This study was conducted to compare secondary intention healing of wounds treated daily with a topical application of commercially available hyaluronic acid (HA), Manuka honey (MH), Acemannan gel (AG), or a placebo. Bilateral wounds were surgically created on the backs of six sheep. At two and six weeks post-wound creation, biopsies were obtained to perform histological, immunohistochemical, and molecular analyses of the wound site. Daily clinical evaluations were performed and weekly photographs were taken of the wounds. HA treatment promoted a physiological progression of the healing process in all wound healing phases, while stimulating an abundant cutaneous adnexa and promoting rapid healing, representing the most compelling treatment. MH-treated wounds were slightly dry. However, the main effect of MH was to promote cell proliferation and neovascularization, with an overall pro-inflammatory effect. Results suggest that MH treatment enhances the healing process. AG treatment dehydrated the wounds and stimulated late granulation tissue and cell proliferation. Moreover, AG-treated wounds produced a mild late pro-inflammatory and neovascularization effect. Our data indicate that AG treatment can have a positive influence on moist wounds with abundant granulation tissue and exudate.

Oncological genetic counseling (OGC) for high-risk hereditary cancer: what can hospital anxiety and depression scale (HADs) tell us?

PURPOSE

This study aimed to verify whether and how anxiety and depression symptoms are associated both to socio-demographic and clinical variables (age, civil status, type of cancer diagnosed, time elapsed between cancer diagnosis and Oncologic Genetic Counseling/OGC, number of relatives affected by cancer) and to psychological features (presence/absence of previous psychological suffering), subjective cancer risk perception, psychological attitude approaching/OGC) in a sample of Caucasian patients accessing OGC.

METHODS

201 participants (193 female and 8 male) accessing OGC in the Istituto di Ricovero e Cura Carattere Scientifico (IRCCS) Giovanni Paolo II in Bari completed the Hospital Depression and Anxiety Scale (HADs) that was analyzed as global scoring, anxiety (HAD-A) and depression subscale (HAD-D).

RESULTS

In our sample, higher HADs, HAD-A and HAD-D scorings were associated in different ways to both socio-demographic information (age: p value 0.019), clinical and medical features (personal history of cancer: HAD-D p value 0.02; months elapsed between diagnosis and OGC, HAD-A p value 0.004 and HADs p value 0.008) and psychological dimensions (approaching genetic counseling: anxiety p value 0.06; fear p value 0.02; duty p value 0.04).

CONCLUSION

This study showed that during the process of oncological genetic counseling the importance of taking into consideration not only medical variables but also cognitive and emotional aspects from both the individual and family spheres, in order to assure adequate care of the patient.

BRCA germline mutation test for all woman with ovarian cancer?

Background

Delivering widespread BRCA testing to patients with ovarian cancer has been suggested by several scientists, recommended by professional societies and solicited by patients organizations. However, based on the lack of studies clearly demonstrating the cost-effectiveness of such approach compared to standard practice, we evaluated the possibility to better select subgroups of ovarian cancer (OC) patients with higher probability to be a BRCA mutation carrier’.

Methods

We analyzed the database of 2222 germline BRCA analyses from OC patients recently published by Song et al. (Song 2014) by applying multivariate and conditional inference regression tree-analyses.

Results

Overall, 178/2192 (8.1%) evaluable OC women showed pathogenic germline mutations in BRCA genes (84 BRCA1;94 BRCA2). BRCA mutations resulted significantly more frequent in Epithelial tumors (10.7%), less differentiated tumours (11.0%) and younger subjects (13.4%). Regression tree analysis permitted to individualize a subset of 66% OC patients with particularly low risk (3.5%) to carry a BRCA mutation vs a subgroup (24% of the series), with a probability higher than 17% to carry a pathogenic mutation. Younger age, OC and Breast Cancer family history were confirmed powerful factors in selecting subgroups of patients with significantly different BRCA mutation probability.

Conclusions

Our regression tree-analysis can represent an innovative approach taking into consideration all main clinical pathological information to select OC patients to be candidated for BRCA test.

Allogeneic mesenchymal stem cells improve the wound healing process of sheep skin

BACKGROUND

Skin wound healing includes a system of biological processes, collectively restoring the integrity of the skin after injury. Healing by second intention refers to repair of large and deep wounds where the tissue edges cannot be approximated and substantial scarring is often observed. The objective of this study was to evaluate the effects of mesenchymal stem cells (MSCs) in second intention healing using a surgical wound model in sheep. MSCs are known to contribute to the inflammatory, proliferative, and remodeling phases of the skin regeneration process in rodent models, but data are lacking for large animal models. This study used three different approaches (clinical, histopathological, and molecular analysis) to assess the putative action of allogeneic MSCs at 15 and 42 days after lesion creation.

RESULTS

At 15 days post-lesion, the wounds treated with MSCs showed a higher degree of wound closure, a higher percentage of re-epithelialization, proliferation, neovascularization and increased contraction in comparison to a control group. At 42 days, the wounds treated with MSCs had more mature and denser cutaneous adnexa compared to the control group. The MSCs-treated group showed an absence of inflammation and expression of CD3+ and CD20+. Moreover, the mRNA expression of hair-keratine (hKER) was observed in the MSCs-treated group 15 days after wound creation and had increased significantly by 42 days post-wound creation. Collagen1 gene (Col1α1) expression was also greater in the MSCs-treated group compared to the control group at both days 15 and 42.

CONCLUSION

Peripheral blood-derived MSCs may improve the quality of wound healing both for superficial injuries and deep lesions. MSCs did not induce an inflammatory response and accelerated the appearance of granulation tissue, neovascularization, structural proteins, and skin adnexa.

Investigations of the corneal epithelium in Veterinary Medicine: State of the art on corneal stem cells found in different mammalian species and their putative application

The existence of progenitor cells that can readily differentiate into a specific cell type is a common cellular strategy for physiological tissue growth and repair mechanisms. In the mammalian cornea, many aspects regarding the nature and location of these cells are still unclear. In the human limbus (peripheral area of the cornea) progenitor cells have been found and characterized but in non-human mammals, the picture is not so clear. In this review, we examine current knowledge about the morphology of limbus and the localization of corneal epithelial stem cells in all species studied so far, comparing data with humans. We have also explored different research directions in the veterinary field in order to discuss the: i) currently used protocols and ii) best range of treatments for ocular pathologies in which corneal stem cells are involved.

Accurate Classification of NF1 Gene Variants in 84 Italian Patients with Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is one of the most common autosomal dominant genetic diseases. It is caused by mutations in the NF1 gene encoding for the large protein, neurofibromin. Genetic testing of NF1 is cumbersome because 50% of cases are sporadic, and there are no mutation hot spots. In addition, the most recognizable NF1 clinical features&mdash;caf&eacute;-au-lait (CALs) spots and axillary and/or inguinal freckling&mdash;appear early in childhood but are rather non-specific. Thus, the identification of causative variants is extremely important for early diagnosis, especially in paediatric patients. Here, we aimed to identify the underlying genetic defects in 72 index patients referred to our centre for NF1. Causative mutations were identified in 58 subjects, with 29 being novel changes. We evaluated missense and non-canonical splicing mutations with both protein and splicing prediction algorithms. The ratio of splicing mutations detected was higher than that reported in recent patients&rsquo; series and in the Human Gene Mutation Database (HGMD). After applying in silico predictive tools to 41 previously reported missense variants, we demonstrated that 46.3% of these putatively missense mutations were forecasted to alter splicing instead. Our data suggest that mutations affecting splicing can be frequently underscored if not analysed in depth. We confirm that hamartomas can be useful for diagnosing NF1 in children. Lisch nodules and cutaneous neurofibromas were more frequent in patients with frameshifting mutations. In conclusion, we demonstrated that comprehensive in silico analysis can be a highly specific method for predicting the nature of NF1 mutations and may help in assuring proper patient care.

Two novel cases of compound heterozygous mutations in mitofusin2: Finding out the inheritance

MFN2 is the major gene involved in the axonal form of Charcot-Marie-Tooth disease. It usually has an autosomal dominant pattern of inheritance, but a few cases of homozygous or compound heterozygous mutations have been described. These patients usually present an earlier onset, more severe phenotype and their inheritance pattern can span from autosomal recessive to semidominant. Here we report two unrelated patients carrying two compound heterozygous MFN2 mutations. Both present a pure axonal neuropathy without any additional features. The first patient presents a mild clinical phenotype with onset in the 2nd decade, while the second patient shows a severe, early onset phenotype with loss of independent ambulation. Only a careful clinical examination as well as neurophysiological and genetic studies allowed us to establish the role and the transmission pattern of the identified variants. We discuss practical consequences of this finding in genetic counseling.

Molecular and Functional Characterization of Three Different Postzygotic Mutations in PIK3CA-Related Overgrowth Spectrum (PROS) Patients: Effects on PI3K/AKT/mTOR Signaling and Sensitivity to PIK3 Inhibitors

Background

PIK3CA-related overgrowth spectrum (PROS) include a group of disorders that affect only the terminal portion of a limb, such as type I macrodactyly, and conditions like fibroadipose overgrowth (FAO), megalencephaly-capillary malformation (MCAP) syndrome, congenital lipomatous asymmetric overgrowth of the trunk, lymphatic, capillary, venous, and combined-type vascular malformations, epidermal nevi, skeletal and spinal anomalies (CLOVES) syndrome and Hemihyperplasia Multiple Lipomatosis (HHML). Heterozygous postzygotic PIK3CA mutations are frequently identified in these syndromes, while timing and tissue specificity of the mutational event are likely responsible for the extreme phenotypic variability observed.

Methods

We carried out a combination of Sanger sequencing and targeted deep sequencing of genes involved in the PI3K/AKT/mTOR pathway in three patients (1 MCAP and 2 FAO) to identify causative mutations, and performed immunoblot analyses to assay the phosphorylation status of AKT and P70S6K in affected dermal fibroblasts. In addition, we evaluated their ability to grow in the absence of serum and their response to the PI3K inhibitors wortmannin and LY294002 in vitro.

Results and Conclusion

Our data indicate that patients’ cells showed constitutive activation of the PI3K/Akt pathway. Of note, PI3K pharmacological blockade resulted in a significant reduction of the proliferation rate in culture, suggesting that inhibition of PI3K might prove beneficial in future therapies for PROS patients.

Characterization of the rs2802292 SNP identifies FOXO3A as a modifier locus predicting cancer risk in patients with PJS and PHTS hamartomatous polyposis syndromes

Background

Hamartomatous polyposis syndromes (HPS) are inherited conditions associated with high cancer risk. They include the Peutz-Jeghers and the PTEN hamartoma tumor syndromes, which are caused by mutations in the LKB1 and PTEN genes, respectively. Estimation of cancer risk is crucial in order to optimize surveillance, but no prognostic markers are currently available for these conditions. Our study relies on a ‘signal transduction’ hypothesis based on the crosstalk between LKB1/AMPK and PI3K/PTEN/Akt signaling at the level of the tumor suppressor protein FoxO3A. Interestingly, the FOXO3A rs2802292 G-allele was shown to be associated with longevity, reduced risk of aging-related diseases and increased expression of FoxO3A mRNA.

Methods

We typed rs2802292 in 150 HPS unrelated patients and characterized the expression of FoxO3A by quantitative PCR and immunoblot analysis in human intestinal cell lines.

Results

We found a significantly higher risk for malignancies in females and TT genotype carriers compared to patients having at least one G-allele. Subgroup analysis for each HPS syndrome revealed a G-allele-associated beneficial effect on cancer risk occurring mainly in males. Molecular characterization of human intestinal cell lines showed that the G-allele significantly correlated with increased basal expression of FoxO3A mRNA and protein.

Conclusion

Our results suggest an inverse correlation between the protective allele (G) copy number and cancer risk, and might be useful to optimize surveillance in HPS patients. Further investigations are needed to confirm our hypothesis and to ascertain whether differences in therapeutic response exist across genotypes.

Autologous bone marrow mesenchymal stromal cells for regeneration of injured equine ligaments and tendons: a clinical report

The use of Mesenchymal Stromal Cells (MSCs) in orthopedic practice has recently and rapidly acquired an important role. Therapies based on the use of MSCs for the treatment of acute injuries as well as chronic inflammatory disorders are gradually becoming clinical routine. These cells have demonstrated intriguing therapeutic potentialities (i.e.: inflammation control, tissue regeneration and pathological scar prevention), that have been taken into consideration for use in both human and veterinary medicine. In particular, horses represent high performance athletes considered models for human pathologies since musculo-skeletal disorders frequently occur in this species. In the past, repair of tendon injures were performed by different methods. In particular, clinical therapy was based on ice application, bandage, box rest and controlled exercise. An alternative approach consisted on the use of corticosteroid (inflammation reduction) and other drugs (sodium hyaluronate, polysulphated glycosaminoglycans, beta aminoproprionitrile fumarate). Furthermore, surgical treatments like accessory ligament desmotomy, local irritation by line firing or pin firing were commonly used. More recently ultrasound, laser therapy, electromagnetic field therapy have been considered. Unfortunately, they did not allow complete tissue healing and quite often animals did not regain competitiveness. In order to minimize this inconvenience, the use of MSCs has been introduced as an alternative to the traditional approach since it represents a potential tool to improve tissue regeneration. Aim of this study was to evaluate the capability of MSCs to improve the functional outcome of horses affected by tendonitis and desmitis. Thirty-three breed and activity-matched horses affected by tendonitis or desmitis, were included in clinical trial scored for lesions and subdivided into two groups. Group 1 animals were treated with autologous MSCs, associated with platelet rich plasma (group 1). Bone marrow samples were collected from the sternum of the treated horses and processed in order to isolate MSCs. Following cell therapy, they were subjected to a rehabilitation period and their ability to resume training was evaluated. In this study, implanted MSCs caused no adverse reactions and thirteen out of the eighteen inoculated horses returned to race competitions. On the contrary, no improvement was seen in the twelve animals of group 2 treated with pin firing, that were not able to resume sport activity. In conclusion the clinical trial proves the safety of equine bone-marrow derived MSCs and a successful outcome of the treated animals that returned to their previous level of sport activity.

Influence of temperature, time and different media on mesenchymal stromal cells shipped for clinical application

Cell-based therapies, such as the use of mesenchymal stromal cells (MSCs), are becoming popular in veterinary medicine. When MSCs are not cryopreserved, they are shipped in suspension, but no previous studies have analyzed MSC viability during delivery. Here, the impact of several experimental shipping conditions on the number of equine blood-derived (ePB-MSC) and canine adipose-derived (cA-MSC) MSCs were evaluated. Among the different parameters tested, only time and temperature influenced MSC number during the experimental shipping conditions. Cells were monitored over different time intervals for gene expression of typical MSC markers and to evaluate acquired resistance to apoptosis and beta-galactosidase activity. Overall, these results indicate that ePB-MSC and cA-MSC should be delivered in phosphate buffered saline at room temperature and within 9-12 h.

Overexpression of histidine-rich calcium binding protein in equine ventricular myocardium

Histidine-rich calcium binding protein (HRC) is a high capacity, low affinity Ca(2+) binding protein, specifically expressed in striated muscles of mammals. In rabbit skeletal and cardiac muscles, HRC binds to sarcoplasmic reticulum (SR) membranes via triadin, a junctional SR protein. Recently, a potential role in heart failure and arrhythmogenesis has been assigned to HRC due to its activity as regulator of SR Ca(2+) uptake and Ca(2+) release. HRC might play a particularly relevant role in the equine heart, given its slower resting heart rate (20-35 beats/min) and longer action potential duration (APD) (0.6-1.0 s) than are found in other mammals. The results from this study showed for the first time direct evidence that HRC protein in equine cardiac muscle was expressed in association with the SR membranes and that HRC transcriptional activity was three times higher in the ventricles compared to the atria. The predominance of HRC mRNA up-regulation in ventricular myocardium was specific to the horse heart, since a more even distribution between atria and ventricles was found in animals of similar body size or species, such as cattle or domestic donkeys.

Canine adipose-derived-mesenchymal stem cells do not lose stem features after a long-term cryopreservation

Adult stem cells are nowadays used for treating several pathologies. A putative stem cell population was found in the adipose tissue of mammals and canine adipose tissue-derived-mesenchymal stem cells (cA-MSC) have been shown to possess the capacity to differentiate into several lineages. The main goal of our research was to fully characterize cA-MSC and examine the effects of cryopreservation on their stemness features. Each sample of cA-MSC was analyzed immediately and then again after being frozen in liquid nitrogen for one year. After the cryopreservation period cells conserved their fibroblast-like morphology, alkaline phosphatase positivity and CD expression but showed a lower proliferation ratio and a lower telomerase activity in comparison with fresh cells. Finally, the cryopreservation protocol did not change the cA-MSC adipogenic, osteogenic and myogenic differentiative potential. Our data demonstrate that stored cA-MSC might represent a promising type of progenitor cell for autologous cellular-based therapies in veterinary medicine.

Hypoxia: the third wheel between nerve and muscle

Skeletal muscles not only obey carefully all motor commands received via motor nerves from nervous system, but also are ready to modify their structure and function to be more suited to the tasks assigned by nervous system. Thus, nervous system appears as the major modulator of the muscle structure and function. Other factors, however, may interfere with the nerve-muscle partnership and among them, hypoxia plays a pivotal role because skeletal muscles exhibit a great variability of the oxygen fluxes and because hypoxia per se has a powerful influence on muscle fibers. The adaptation of skeletal muscles to nerve-induced activity is particularly evident with low frequency tonic patterns and examples are given by chronic low frequency stimulation and by endurance training. Adaptation includes fiber type transitions towards a slow-oxidative phenotype, increased mitochondrial density and increased capillary/fiber ratio. Hypoxia can trigger some of such changes and this has suggested that low oxygen tension at fiber level might be a mediator, possibly based on HIF and VEGF, of the muscle adaptation to increased contractile activity. Chronic hypoxia can, however, induce opposite modifications, such as a fiber type transition from slow-oxidative to fast-glycolytic and mitochondrial loss. In such conditions, the increased contractile activity can antagonize hypoxia effects. Thus, hypoxia can play a double role in the nerve-muscle relationship, either reinforcing the nerve influence or antagonizing it. This short review aims to re-examine the ambiguous relationships between nerve-induced contractile activity and hypoxic conditions and to suggest possible interpretations of the double role played by hypoxia.

Glial cell line-derived neurotrophic factor expression in the brain of adult zebrafish (Danio rerio)

In mammals, glial cell line-derived neurotrophic factor (GDNF) is a growth factor of many neuronal populations in the central, peripheral and autonomous nervous system. GDNF may also function as a morphogen during kidney development and may regulate spermatogonial differentiation. GDNF has been characterised in zebrafish embryos and was demonstrated experimentally to be critical for the development of the enteric nervous system. However, in adult zebrafish, no data exist regarding GDNF expression and localisation in the brain and in different organs. Thus, the aim of the present study was to investigate the expression of GDNF in the brain of adult zebrafish (Danio rerio). Transcripts of GDNF mRNA were observed in brain extracts by a standard RT-PCR. The presence of the protein in the brain homogenates was confirmed by SDS-PAGE electrophoresis and Western blotting analysis. Immunohistochemistry and in situ hybridization experiments showed that GDNF protein and mRNA were localised in various nuclei of the telencephalon, diencephalon, mesencephalon, cerebellum and medulla oblongata of the zebrafish brain. In conclusion, this study showed that the expression of GDNF was not restricted to developmental periods but it seems that this factor might be involved in adult zebrafish brain physiology, as observed in mammals.

Quantitative RT-PCR analysis and immunohistochemical localization of HSP70 in sea bass Dicentrarchus labrax exposed to transport stress

In aquaculture, fish are exposed to stressful conditions, which cause an increased synthesis of heat shock proteins (HSPs) at the cellular level. In this work we considered the expression of the constitutive and inducible forms of HSP70 as an indicator of stress caused by transport, during development of the sea bass (Dicentrarchus labrax), a teleost fish of high value for aquaculture. Qualitative RT-PCR analysis revealed expression of inducible HSP70 gene in larvae and fry (25, 40 and 80 days) as well as in adult tissues (liver, brain, muscle, gills, kidney, gonads, heart, spleen and skin) of both control and stressed animals. Expression of inducible HSP70 mRNA examined in different adult tissues by Real-Time PCR, was significantly higher in skin and skeletal muscle of stressed animals than in controls. Immunolocalization of inducible and constitutive forms of heat shock protein 70 (HSP70 and HSC70), reported here for the first time, demonstrated an ubiquitous distribution of HSC70 protein in several tissues of both stressed and control animals (at all stages), while inducible HSP70 protein was found only in skeletal muscle of stressed animals. In all stressed animals, regardless of their developmental stage, cortisol levels were higher than in control animals.

Expression of eight distinct MHC isoforms in bovine striated muscles: evidence for MHC-2B presence only in extraocular muscles

This study aimed to analyse the expression of myosin heavy chain (MHC) isoforms in bovine muscles, with particular attention to the MHC-2B gene. Diaphragm, longissimus dorsi, masseter, several laryngeal muscles and two extraocular muscles (rectus lateralis and retractor bulbi) were sampled in adult male Bos taurus (age 18-24 months, mass 400-500 kg) and analysed by RT-PCR, gel electrophoresis and immunohistochemistry. Transcripts and proteins corresponding to eight MHC isoforms were identified: MHC-alpha and MHC-beta/slow (or MHC-1), two developmental isoforms (MHC-embryonic and MHC-neonatal), three adult fast isoforms (MHC-2A, MHC-2X and MHC-2B) and the extraocular isoform MHC-Eo. All eight MHC isoforms were found to be co-expressed in extrinsic eye muscles, retractor bulbi and rectus lateralis, four (beta/slow, 2A, 2X, neonatal) in laryngeal muscles, three (beta/slow, 2A and 2X) in trunk and limb muscles and two (beta/slow and alpha) in masseter. The expression of MHC-2B and MHC-Eo was restricted to extraocular muscles. Developmental MHC isoforms (neonatal and embryonic) were only found in specialized muscles in the larynx and in the eye. MHC-alpha was only found in extraocular and masseter muscle. Single fibres dissected from masseter, diaphragm and longissimus were classified into five groups (expressing, respectively, beta/slow, alpha, slow and 2A, 2A and 2X) on the basis of MHC isoform electrophoretical separation, and their contractile properties [maximum shortening velocity (v(0)) and isometric tension (P(0))] were determined. v(0) increased progressively from slow to fast 2A and fast 2X, whereas hybrid 1-2A fibres and fibres containing MHC-alpha were intermediate between slow and fast 2A.

Myosin heavy chain 2B isoform is expressed in specialized eye muscles but not in trunk and limb muscles of cattle

Myosin heavy chain isoforms (MHC) of adult skeletal muscles are codified by four genes named: slow, or type 1, and fast types 2A, 2X and 2B. The slow, 2A and 2X isoforms have been found expressed in all mammalian species studied so far whereas there is a large inter-species variability in the expression of MHC-2B. In this study histochemistry (m-ATPase), immunohistochemistry with the use of specific monoclonal antibodies and RT-PCR were combined together to assess whether the MHC-2B gene is expressed in bovine muscles. ATPase staining and RT-PCR experiments showed that three MHC isoforms (1, 2A, 2X) were expressed in trunk and limb muscles. Slow or type 1 expression was confirmed using a specific antibody (BA-F8) whereas the detection of fast MHC isoforms were validate by means of BF-35 antibody although not by the SC-71 antibody. MHC-2B was absent in limb and trunk muscles, but was present in specialized eye muscles (rectus lateralis and retractor bulbi) as consistently showed by RT-PCR and reactivity with a specific antibody (BF-F3). Interestingly, a cardiac isoform, MHC-a-cardiac was found to be expressed not only in extraocular muscles but also in masticatory muscles as masseter.

Expression and cellular localization of insulin-like growth factor-II protein and mRNA in Sparus aurata during development

The spatial localization of IGF-II protein and mRNA was investigated during larval and postlarval developmental stages of the gilthead sea bream (Sparus aurata) by immunohistochemistry and in situ hybridization, using specific antisera and riboprobes. Steady-state levels of IGF-II mRNA in larvae were determined by Northern blot analysis and were found to be increased. Immunoreactivity towards IGF-II was found in larval skin, muscle, gills, gut, olfactory epithelium and kidney. After metamorphosis, the strongest immunoreactivity was found in red skeletal muscle. Positive reaction with IGF-II antibodies was also found in the olfactory epithelium and in the epithelia of pharynx, oesophagus, stomach and kidney. In the adult, the most intense signal was observed in the red and pink musculature and in heart musculature. Immunostaining was also found in saccus vasculosus, thymus, spleen and ovary. IGF-II mRNA was detected by in situ hybridization in the brain, olfactory epithelium, eye, pharynx, skeletal musculature and liver. The spatial distribution of IGF-II shown in this study is consistent with previous findings on the cellular localization of IGF type 1 receptor in the sea bream and supports a role for IGF-II during development and growth of sea bream. Furthermore, these results suggest that IGF-II acts in an autocrine/paracrine manner.

Anbmp2/4 is a new member of the transforming growth factor-beta superfamily isolated from a crinoid and involved in regeneration

Invertebrates have frequently been used to help understand the complexities of regulatory gene function and evolution. The bone morphogenetic proteins (BMPs) are a highly conserved group of secreted regulatory factors that play an important part in early embryonic patterning. In the present study we have used the remarkable regenerative potential of crinoid echinoderms to explore the BMPs' site of expression in an adult developmental programme. Our results suggest that a crinoid BMP2/4 homologue is actively involved during the early stages of blastemal regeneration at a time when fundamental patterns are being established. This supports the idea of an evolutionary developmental programme where essential gene families are conserved throughout phylogeny in terms of both expression and function.

Localization of IGF-I, IGF-I receptor, and IGFBP-2 in developing Umbrina cirrosa (Pisces: Osteichthyes)

In this study, the distribution of IGF-I, IGF type I receptor (IGF-IR), and IGF-binding protein 2 (IGFBP-2) was investigated during larval and post-larval developmental stages of the shi drum (Umbrina cirrosa) by immunohistochemistry using antisera raised against Sparus aurata IGF-I and IGF-IR, and against mouse IGFBP-2. Immunoreactivity of the mitogenic marker PCNA (proliferating cell nuclear antigen) was used for assessment of cellular proliferation. Distribution of IGF-I mRNA was studied by in situ hybridization. IGF-I immunoreactivity was detected in liver and developing intestine already in 1-5 day post-hatching larvae. From day 11, immunostaining in the intestine was evident in the enterocytes of the anterior intestine and in the apical zone of the epithelium of developing posterior intestine. Positive reaction with IGF-I antibody was also detected in chondrocytes, in the epithelium of the skin, gills and in the central nervous system (CNS), and lateral muscle. At hatching IGF-IR immunoreactivity was already detectable in developing CNS, notochord, and skin. From day 6 immunostaining was evident in the olfactory epithelium, in eyes and from day 11 in the developing olfactory bulbs and CNS. Positive reaction with IGF-IR antibody was also detected in chondrocytes, in the epithelium of the skin, gills, heart, and in the lateral muscle. Immunoreactive IGFBP-2, as detected by anti-mouse IGFBP-2 antiserum, exhibited generally a similar distribution pattern to that of IGF-I and IGF-IR. In situ hybridization, which has been performed by using riboprobes from S. aurata cDNA, revealed IGF-I mRNA in skeletal musculature, liver, and CNS. These data strongly suggest a role for the IGF system during development and growth of U. cirrosa.

Expression of transforming growth factor beta-like molecules in normal and regenerating arms of the crinoid Antedon mediterranea: immunocytochemical and biochemical evidence

The phylum Echinodermata is well known for its extensive regenerative capabilities. Although there are substantial data now available that describe the histological and cellular bases of this phenomenon, little is known about the regulatory molecules involved. Here, we use an immunochemical approach to explore the potential role played by putative members of the transforming growth factor-beta (TGF-beta) family of secreted proteins in the arm regeneration process of the crinoid Antedon mediterranea. We show that a TGF-beta-like molecule is present in normal and regenerating arms both in a propeptide form and in a mature form. During regeneration, the expression of the mature form is increased and appears to be accompanied by the appearance of an additional isoform. Immunocytochemistry indicates that TGF-beta-like molecules are normally present in the nervous tissue and are specifically localized in both neural elements and non-neural migratory cells, mainly at the level of the brachial nerve. This pattern increases during regeneration, when the blastemal cells show a particularly striking expression of this molecule. Our data indicate that a TGF-beta-like molecule (or molecules) is normally present in the adult nervous tissues of A. mediterranea and is upregulated significantly during regeneration. We suggest that it can play an important part in the regenerative process.

Molecular approach to echinoderm regeneration

Until very recently echinoderm regeneration research and indeed echinoderm research in general has suffered because of the lack of critical mass. In terms of molecular studies of regeneration, echinoderms in particular have lagged behind other groups in this respect. This is in sharp contrast to the major advances achieved with molecular and genetic techniques in the study of embryonic development in echinoderms. The aim of our studies has been to identify genes involved in the process of regeneration and in particular neural regeneration in different echinoderm species. Our survey included the asteroid Asterias rubens and provided evidence for the expression of Hox gene homologues in regenerating radial nerve cords. Present evidence suggests: 1) ArHox1 expression is maintained in intact radial nerve cord and may be upregulated during regeneration. 2) ArHox1 expression may contribute to the dedifferentiation and/or cell proliferation process during epimorphic regeneration. From the crinoid Antedon bifida, we have been successful in cloning a fragment of a BMP2/4 homologue (AnBMP2/4) and analysing its expression during arm regeneration. Here, we discuss the importance of this family of growth factors in several regulatory spheres, including maintaining the identity of pluripotent blastemal cells or as a classic skeletal morphogenic regulator. There is clearly substantial scope for future echinoderm research in the area of molecular biology and certain aspects are discussed in this review.

Regenerative response and endocrine disrupters in crinoid echinoderms: arm regeneration in Antedon mediterranea after experimental exposure to polychlorinated biphenyls

Regenerative phenomena, which have the advantage of reproducing developmental processes in the adult organism, are very sensitive to environmental stress and represent stages that can be monitored for damage at the whole-organism, cellular and molecular levels. Some persistent and ubiquitous pollutants, which can affect the natural environment because of their bioaccumulation in organisms, exert their effects by acting as ‘endocrine disrupters’. In this respect, they can cause dysfunction in steroid hormone production/metabolism and activity by their dramatic effects on gene expression, reproductive competence and growth. The aim of our present research was to assess the impact of such compounds on adult echinoderm reproductive physiology with particular reference to regeneration potential. It is known that vertebrate-type steroids are synthesized by echinoderms and play a role in the control of growth and reproduction. Our experimental model is the crinoid Antedon mediterranea, selected on the basis of its previously explored regenerative capabilities at the level of the arms. The regeneration response, analyzed at the tissue and cellular levels using both light and electron microscopy and immunocytochemistry, was employed to monitor the effects of exposure to persistent endocrine disrupter micropollutants such as polychlorinated biphenyls (PCBs) by means of laboratory tests performed under controlled conditions in terms of environmental variables and contamination levels. Our results indicate that exposure to endocrine disrupter compounds such as PCBs can induce anomalies in regeneration times, morphology and developmental mechanisms that can be interpreted in the light of significant dysfunctions in the endocrine mechanisms controlling regenerative development.

Growth factors, heat-shock proteins and regeneration in echinoderms

The study of regeneration in armed echinoderm species, including crinoids, ophiuroids and asteroids, is attracting increasing attention. Recent interest has focused on the presence and potential role of growth factors, including members of the nerve growth factor (NGF) and transforming growth factor-beta (TGF-beta) families, in the regenerative process and their possible relationship to the normal developmental (ontogenetic) regulatory cascade. In addition, the expression patterns of the heat-shock family of stress proteins (Hsps) during regeneration are also important. Their role forms part of a normal stress response to the trauma of autotomy in combination with a putative function in tissue remodelling and associated protein turnover during regeneration. The temporal dynamics of the stress response may also be strongly indicative of environmentally adaptive pressures operating on these systems.

Changes in ubiquitin conjugates and Hsp72 levels during arm regeneration in echinoderms

All organisms show a common defensive mechanism that results in the expression of conserved heat shock proteins (Hsps). These proteins function in a wide range of stressful conditions. We have monitored their levels in species of regenerating echinoderms with different mechanisms of regeneration and from different geographical locations. The effect of an artificial higher temperature on expression of Hsps was also studied. Two stress proteins (Hsp72 and ubiquitin) that are important in processes such as development and protein degradation were investigated. Using Western blot analysis and immunocytochemistry, we found significant changes in the level (Hsp72) and pattern of conjugation (ubiquitin) that corresponded with the repair phase (early regenerative stages) and with the later growth and regeneration of new tissues. Animals from the intertidal environment showed a distinctly sustained expression pattern of Hsp72 compared with benthic animals which suggests a functionally adaptative and dynamic stress response program.

Muscle growth in response to changing demands of functions in the teleost Sparus aurata (L.) during development from hatching to juvenile

Growth of laterarl muscle in the teleost fish Sparus aurata (L.) was examined from hatching to juvenile by a basic morphofunctional approach that takes into account structural and ecophysiological aspects and combines in vivo observations and LM and TEM microscopic analysis. As shown in most teleost fishes, muscle growth proceeds by a double mechanism of hyperplasia and hypertrophy that contribute differentially to the overall development of the lateral muscle, giving rise in each myomere to a typical pattern of structurally and functionally different fibre types (slow-red and fast-white fibres, plus pink intermediate fibres) in a nerve-dependent process. During larval life the muscle growth takes place mainly due to hyperplastic growth at the level of specific proliferative zones of the myomeres, from which slow, pink and white muscle fibres are derived. In those species that reach a large adult size a new typical hyperplastic process disseminated throughout the fast white muscle layer takes place during post-larval life. In contrast, hypertrophic growth occurs in all stages, but is the dominant mechanism of muscle growth only in juvenile and adult. The suitable recruitment of the different fibre types enables the fish to optimize its performances according to specific functional and metabolic requirements related to the swimming behaviour and hydrodynamic regimes. The different mechanisms of growth are here analysed in their detailed structural and ultrastructural aspects in order to interpret their adaptive significance in the light of the fish life cycle, with particular reference to locomotion and feeding behaviour.

Cellular and molecular mechanisms of arm regeneration in crinoid echinoderms: the potential of arm explants

Crinoid echinoderms can provide a valuable experimental model for studying all aspects of regenerative processes from molecular to macroscopic level. Recently we carried out a detailed study into the overall process of arm regeneration in the crinoid Antedon mediterranea and provided an interpretation of its basic mechanisms. However, the problem of the subsequent fate of the amputated arm segment (explant) once isolated from the animal body and of its possible regenerative potential have never been investigated before. The arm explant in fact represents a simplified and controlled regenerating system which may be very useful in regeneration experiments by providing a valuable test of our hypotheses in terms of mechanisms and processes. In the present study we carried out a comprehensive analysis of double-amputated arm explants (i.e. explants reamputated at their distal end immediately after the first proximal amputation) subjected to the same experimental conditions as the regenerating donor animals. Our results showed that the explants undergo similar regenerative processes but with some significant differences to those mechanisms described for normal regenerating arms. For example, whilst the proximal-distal axis of arm growth is maintained, there are differences in terms of the recruitment of cells which contribute to the regenerating tissue. As with normal regenerating arms, the present work focuses on (1) timing and modality of regeneration in the explant; (2) proliferation, migration and contribution of undifferentiated and/or dedifferentiated/transdifferentiated cells; (3) putative role of neural growth factors. These problems were addressed by employing a combination of conventional microscopy and immunocytochemistry. Comparison between arm explants and regenerating arms of normal donor adults indicates an extraordinary potential and regenerative autonomy of crinoid tissues and the cellular plasticity of the phenomenon.