Dementia, osteoporosis and fragility fractures: Intricate epidemiological relationships, plausible biological connections, and twisted clinical practices.

Dementia, osteoporosis, and fragility fractures are chronic diseases, often co-existing in older adults. These conditions pose severe morbidity, long-term disability, and mortality, with relevant socioeconomic implications. While in the research arena, the discussion remains on whether dementia is the cause or the consequence of fragility fractures, healthcare professionals need a better understanding of the interplay between such conditions from epidemiological and physiological standpoints. With this review, we summarized the available literature surrounding the relationship between cognitive impairment, dementia, and both low bone mineral density (BMD) and fragility fractures. Given the strength of the bi-directional associations and their impact on the quality of life, we shed light on the biological connections between brain and bone systems, presenting the main mediators, including gut microbioma, and pathological pathways leading to the dysregulation of bone and brain metabolism. Ultimately, we synthesized the evidence about the impact of available pharmacological treatments for the prevention of fragility fractures on cognitive functions and individuals' outcomes when dementia coexists. Vice versa, the effects of symptomatic treatments for dementia on the risk of falls and fragility fractures are explored. Combining evidence alongside clinical practice, we discuss challenges and opportunities related to the management of older adults affected by cognitive impairment or dementia and at high risk for fragility fracture prevention, which leads to not only an improvement in patient health-related outcomes and survival but also a reduction in healthcare cost and socio-economic burden.

Patients' needs in proton therapy: A survey among ten European facilities.

Aims: The number of Proton Therapy (PT) facilities is still limited worldwide, and the access to treatment could be characterized by patients' logistic and economic challenges. Aim of the present survey is to assess the support provided to patients undergoing PT across Europe. Methods: Through a personnel contact, an online questionnaire (62 multiple-choice and open-ended questions) via Microsoft Forms was administered to 10 European PT centers. The questionnaire consisted of 62 questions divided into 6 sections: i) personal data; ii) general information on clinical activity; iii) fractionation, concurrent systemic treatments and technical aspects of PT facility; iv) indication to PT and reimbursement policies; v) economic and/ or logistic support to patients vi) participants agreement on statements related to the possible limitation of access to PT. A qualitative analysis was performed and reported. Results: From March to May 2022 all ten involved centers filled the survey. Nine centers treat from 100 to 500 patients per year. Paediatric patients accounted for 10-30%, 30-50% and 50-70% of the entire cohort for 7, 2 and 1 center, respectively. The most frequent tumours treated in adult population were brain tumours, sarcomas and head and neck carcinomas; in all centers, the mean duration of PT is longer than 3 weeks. In 80% of cases, the treatment reimbursement for PT is supplied by the respective country's Health National System (HNS). HNS also provides economic support to patients in 70% of centers, while logistic and meal support is provided in 20% and 40% of centers, respectively. PT facilities offer economic and/or logistic support in 90% of the cases. Logistic support for parents of pediatric patients is provided by HNS only in one-third of centers. Overall, 70% of respondents agree that geographic challenges could limit a patient's access to proton facilities and 60% believe that additional support should be given to patients referred for PT care. Conclusions: Relevant differences exist among European countries in supporting patients referred to PT in their logistic and economic challenges. Further efforts should be made by HNSs and PT facilities to reduce the risk of inequities in access to cancer care with protons.

25(OH) vitamin D and functional outcomes in older adults admitted to rehabilitation units: the safari study.

Vitamin D (25(OH)D) deficiency is associated with poor physical performance; little is known about its impact on geriatric rehabilitation. We found a positive non-linear relationship between 25(OH)D and functional gain, stronger in levels < 16 ng/ml (below the cutoff for "deficiency"). An early 25(OH)D dosage may be advisable for this population. INTRODUCTION: Vitamin D (25(OH)D) deficiency is highly prevalent in older people, and it is associated with poor muscular strength and physical performance. Its impact on functional outcomes during geriatric rehabilitation has been poorly studied. We aim to analyze the association between 25(OH)D and functional recovery in geriatric rehabilitation units. METHODS: We conducted a prospective multi-center cohort study including patients ≥ 65 years old admitted to 3 geriatric rehabilitation units in Italy and Spain, after orthopedic events or stroke. Outcomes were absolute functional gain (AFG, discharge-admission Barthel index) and ability to walk (AW) at 3 months after admission. The association between 25(OH)D quartiles (Q1-Q2-Q3-Q4) and outcomes was explored using linear or logistic regression models. RESULTS: We included 420 patients (mean age = 81.2 years [SD = 7.7], 66.4% females, mean 25(OH)D concentration = 13.5 ng/ml [SD = 8.7]) (to convert to nmol/l multiply by 2.496). A non-linear relationship between 25(OH)D and AFG was found, with a stronger association for 25(OH)D levels < 16 ng/ml. Compared to Q1 (25(OH)D ≤ 6 ng/ml), participants in Q3 (25(OH)D 11.5-18.2 ng/ml) had the best AFG and AW (mean AFG [SD], Q1 = 28.9 [27.8], Q2 = 32.5 [23.5], Q3 = 43.1 [21.9], Q4 = 34.5 [29.3], R2 = 7.3%; AW, Q1-Q2 = 80%, Q3 = 91%, Q4 = 86%). Regression models adjusted for potential confounders confirmed these results (AGF Q2, ß = 2.614, p = 0.49; Q3, ß = 9.723, p < 0.01; Q4, ß = 4.406, p = 0.22; AW Q2, OR [95% CI] = 1.84 [0.67-5.33]; Q3, OR [95% CI] = 4.01 [1.35-13.48]; Q4, OR [95% CI] = 2.18 [0.81-6.21]). CONCLUSIONS: In our study, 25(OH)D concentration showed a positive association with functional outcomes at 3 months. The association is stronger below the usual cutoff for "deficiency." Dosage of 25(OH)D concentration may help identify geriatric rehabilitation patients at risk for a worse functional recovery.

Analysis of volatile organic compounds: an innovative approach to heart failure characterization in older patients.

BACKGROUND: Analysis of exhaled volatile organic compounds (VOCs) may be applied for diagnostic purposes in some chronic diseases, but there are no data on their role for discriminating people with congestive heart failure (CHF), particularly in older patients where natriuretic peptides have lower accuracy. We evaluated whether VOCs analysis can discriminate patients with or without CHF, stratify CHF severity and predict the response to therapy of decompensated CHF. METHODS AND RESULTS: We recruited 89 subjects admitted to an acute care ward with acutely decompensated CHF, 117 healthy controls and 103 chronic obstructive pulmonary disease (COPD) controls. CHF patients performed echocardiography. VOCs were collected using the Pneumopipe® and analyzed with the BIONOTE electronic nose. Partial least square analysis was used to evaluate the discriminative capacity of VOCs. Accuracy in discrimination of CHF versus healthy and COPD controls was 81% and 69%, respectively; accuracy did not decrease in a sensitivity analysis excluding subjects younger than 65 and older than 80 years. In CHF patients VOCs pattern could predict with fair precision ejection fraction and systolic pulmonary arterial pressure, but not changes in weight due to therapy. CONCLUSIONS: VOCs pattern is able to discriminate older CHF patients from healthy people and COPD patients and correlates with cardiac function markers.

Prototypical versus contemporary Mediterranean Diet.

BACKGROUND AND AIMS: To investigate the evolution of the Mediterranean Diet (MD) in a delimited area of Southern Italy, by comparing the diet adopted 60-70 years ago (Prototypical Mediterranean Diet, PMD) with the contemporary one (Contemporary Mediterranean Diet, CMD), and to verify to what extent they fitted the recommendations of the Italian and the USDA dietary guidelines. METHODS: We recruited a total of 106 participants, divided in two groups. PMD group included 52 women aged >80 years, with a good cognitive function and full independence in basic and instrumental activities of daily living. CMD group included 20 men and 34 women aged 50-60 years. Food intake was assessed by administering the EPIC food frequency questionnaire to each participant, and an additional survey to the PMD subjects only. RESULTS: Both PMD and CMD showed adequate intakes of macronutrients, although some deficiencies related to micronutrient requirements were evident. CMD showed a slightly greater use of animal products, processed and sugary foods, and higher intakes of simple sugars, animal proteins (49.6 vs 28.3 g/day), animal lipids (37.8 vs 20.1 g/day), saturated fats (25.0 vs 15.8 g/day) and cholesterol (305.0 vs 258.5 g/day). PMD showed many similarities to the original version of the MD in terms of macronutrients distribution and food choices. CONCLUSION: The documented evolution of the dietary habits over a 70 years timespan suggests that nowadays Mediterranean regions adhere less strictly to the original MD, although nutrients intakes are adequate to LARN and USDA recommendations.

[Children exposed to multidrug-resistant tuberculosis: How should we manage? Analysis of 46 child contacts and review of the literature]. / Enfants au contact d'individus atteints d'une tuberculose multi-résistante : quelles stratégies adopter ? Analyse de 46 enfants contacts et revue de la littérature.

INTRODUCTION: Tuberculosis-related morbidity and mortality remain important. Emergence and diffusion of multidrug-resistance tuberculosis (MDR-TB) is a global public health concern. Cases of MDR-TB in children are a sentinel event indicating the spread of a mycobacterial strain within a community. Latent TB precedes MDR-TB and screening and follow-up of contact individuals are key points of TB infection control. METHODS: We performed the case-investigation of 20 adult cases of MDR-TB managed in our institution. RESULTS: Forty-six pediatric contact individuals were identified. A high proportion of these children were lost to follow-up (80% at 12 months), showing that monitoring this reservoir population with migrant history is challenging. Five (11%) children presented a secondary infection: one child was diagnosed with active TB infection (positive tuberculin skin test associated with abnormalities on chest computer tomography [CT] scan). Four children were diagnosed with latent TB infection (isolated positive tuberculin skin test with normal CT scan). Two of these children received a treatment adjusted to the strain of the index case. DISCUSSION: In the setting of emerging MDR-TB, tuberculin skin test may be likely replaced by specific interferon-gamma release assays (IGRA), independent of prior BCG vaccination. In addition, chest CT scan is preferred to chest X-ray to detect TB lesions. The management of latent TB infection is controversial: immediate treatment with second-line anti-TB drugs adapted to the index case strain or, consistently with WHO guidelines, a simple follow-up with subsequent treatment in case of active TB.

Clinical and echocardiographic characteristics of elderly hospitalized patients with high levels of NT-proBNP without clinical diagnosis of heart failure.

BACKGROUND: Patients with high NT-proBNP levels but without heart failure (HF) diagnosis have a higher risk of cardiovascular events and mortality; however, there are few data about their characteristic, especially in the elderly. AIMS: To compare the clinical and echocardiographic characteristics of elderly hospitalized patients with and without increased NT-proBNP and with and without a diagnosis of HF. METHODS: We reviewed 209 charts of patients admitted to an acute care ward (mean age 78.9 years, SD 10.2, 62% women). We classified the patients into four groups: no HF with or without increased (>900 pg/mL) NT-proBNP (HF-/BNP-, N = 89 and HF-/BNP+, N = 41), and HF with or without increased NT-proBNP (HF+/BNP-, N = 4 and HF+/BNP+, N = 75). The groups were compared with respect to demographic and clinical characteristics, symptoms at admission, comorbidities, echocardiographic parameters, and cardiovascular events at 180 days. RESULTS: Patients in the groups HF+/BNP+ and HF-/BNP+ were older, with higher serum creatinine, blood urea nitrogen, and lower serum hemoglobin compared to patients in the HF-/BNP- group. The prevalence of ischemic heart disease, pulmonary hypertension, and atrial fibrillation progressively decreased across the HF+/BNP+, HF-/BNP+, and HF-/BNP- groups. The prevalence of abnormal echocardiographic findings in the HF-/BNP+ group was intermediate compared to the other two groups for severe aortic or mitralic regurgitation, monophasic transmitralic pattern, biatrial atriomegaly, ejection fraction, akinesia extension, and PAPs. The same pattern was observed for cardiovascular events at follow-up. DISCUSSION: Elderly patients without a diagnosis of HF, but with high NT-proBNP serum concentration have intermediate clinical characteristics compared to the other two groups. CONCLUSION: NT-proBNP may be a useful marker of silent cardiac damage.

Colistin bladder instillation, an alternative way of treating multi-resistant Acinetobacter urinary tract infection: a case series and review of literature.

The multiresistant Acinetobacter species bacteria are frequently involved in urinary or respiratory tract infections, and one of the most effective drugs, colistine, is associated with significant nephrotoxicity and neurotoxicity. Given that very high concentrations of colistine into biological fluids are safe for the human organism, attempts have been made at delivering the drug topically, by aerosol, or, occasionally, intratechally or intraventricularly for meningitis. These topical treatments could eradicate the Pseudomonas sp. from the lung of patients with cystic fibrosis or bronchiectasis and the Acinetobacter baumannii from lung and meninges. However, only one case of colistin topic treatment in urinary tract infection is described. We report a case series of three patients successfully undergone colistin bladder instillations for multi drug resistant Acinetobacter urinary tract infection, and we review the literature about colistin topic treatment.

Antimicrobial peptides from plants: stabilization of the γ core of a tomato defensin by intramolecular disulfide bond.

Cysteine-containing antimicrobial peptides of diverse phylogeny share a common structural signature, the γ core, characterized by a strong polarization of charges in two antiparallel ß sheets. In this work, we analyzed peptides derived from the tomato defensin SolyC07g007760 corresponding to the protein γ core and demonstrated that cyclization of the peptides, which results in segregation of positive charges to the turn region, produces peptides very active against Gram negative bacteria, such as Salmonella enterica and Helicobacter pylori. Interestingly, these peptides show very low hemolytic activity and thus represent a scaffold for the design of new antimicrobial peptides.

The oxygen therapy.

Oxygen (O(2)) is a vital element. Shortage of O(2) results in deranged metabolism and important changes in vascular tone with opposite effects on the systemic and pulmonary circulation. During hypoxemia, oxidative stress exposes the organism to a sort of accelerated senescence as well as to several acute untoward effects. Thus, hypoxemia should be promptly recognized and treated, hopefully by measures tailored to the pathophysiological mechanisms underlying hypoxemia. However, O(2) therapy remains the most common therapy of hypoxemia, but it must be carefully tailored to relieve hypoxemia without provoking hyperoxia or hypercarbia. Then, the individual response to O(2) as well as changing needs of O(2) during sleep or exercise must be evaluated to provide the best O(2) therapy. Hyperoxia, the effect of overcorrection of hypoxia, can dramatically impact the health status and threaten the survival of the newborn and, through different mechanisms and effects, the adult. A thorough knowledge of the pathophysiological bases of hypoxemia and O(2) storage and delivery devices is then mandatory to administer O(2) therapy guaranteeing for optimal correction of hypoxemia and minimizing the risk of hyperoxia. Consistent with this aim also is a careful scrutiny of instruments and procedures for monitoring the individual response to O(2) over time. Thus, at variance from classical pharmacological therapy, performing O(2) therapy requires a vast array of clinical and technical competences. The optimal integration of these competences is needed to optimize O(2) therapy on individual bases.

Effects of clinical and laboratory variables at admission and of in-hospital treatment with cardiovascular drugs on short term prognosis of ischemic stroke. The GIFA study.

INTRODUCTION: No information exists, to our knowledge, about the possible role of cardiovascular drug administration in the acute phase of ischemic stroke and possible effects on stroke outcome. The aim of our study was to evaluate the relationship between in-hospital treatment with cardiovascular drugs in patients with acute ischemic stroke and some outcome indicators. METHODS AND RESULTS: 1096 subjects enrolled in the GIFA study, who had a main discharge diagnosis of ischemic stroke represent the final sample. Drugs considered for the analysis were the following: ACE-inhibitors (ACEI), angiotensin II receptor blockers (ARBs), statins, calcium-channel-blockers (CCBs), antiplatelet (APL) drugs, antivitamin-k (VKAs), and heparins. As outcome indicators we choose in-hospital mortality, cognitive function evaluated by Hodkinson Abbreviated Mental Test (HAMT), and functional status evaluated by activity daily living (ADL). Indicators of a good outcome were: no in-hospital mortality, HAMT >6 and 0 ADL impaired. Patients with a good outcome showed a higher rate of in-hospital treatment with ACE-inhibitors, calcium-channel blockers and a lower rate of pre-treatment with heparin. CONCLUSIONS: Our study suggests that if a patient with acute ischemic stroke has higher SBP at admission, higher total cholesterol plasma levels, a lower Charlson index and is treated with ACE-inhibitors, calcium channel blockers and antiplatelet drugs, the short term outcome is better in terms of in-hospital mortality and functional indicators such as cognitive and functional performance at discharge.

Association of peripheral venous disease with arterial endothelial dysfunction: a proof-of-concept study.

The objective of the study was to evaluate the association between peripheral venous disease (PVD) and arterial endothelial dysfunction (ED). Arterial and venous diseases have been always considered as two completely different entities, but the recent discovery of a relationship between arterial and venous thrombosis have challenged this assumption. ED, considered to be an early process in the pathophysiology of atherosclerotic disease, could represent a common pathogenetic background. We studied 39 healthy volunteers (median age: 34 years; men: 25.6%). PVD was diagnosed using ultrasound examination, arterial ED using flow-mediated dilation (FMD) and FMD normalized for the peak shear rate (nFMD). Compared with controls, participants with PVD had a lower FMD (15.2 versus 23.4%, P < 0.001) and nFMD (12.7 × 10(-3) versus 19 × 10(-3)/second, P < 0.001). People with the most clinically evident disease had the worst endothelial function. In conclusion, our findings, if confirmed in larger population, might corroborate the idea that venous and arterial disease could have common causes.

Effect of local and remote ischemic preconditioning on endothelial function in young people and healthy or hypertensive elderly people.

To verify whether age affects remote preconditioning, we compared healthy young people (mean age = 28.0 years, SD: 7.2), healthy elderly people (age = 69.2 years, SD: 5.0), and hypertensive elderly people (group 3, age = 72.8 years, SD: 3.9). Each group included 10 participants. The flow-mediated-dilation (FMD) was measured after local (same arm) and remote (leg) ischemic preconditioning. Healthy elderly people had the greatest increase of FMD after ischemic preconditioning compared to baseline (173% after local and 181% after remote preconditioning) and young participants the smallest increase (77% after local and 69% after remote preconditioning) while hypertensive elderly had an intermediate increase (P for comparison across groups: 0.347 for local and 0.064 for remote preconditioning). However, absolute values of FMD after preconditioning were much lower in elderly hypertensive than in healthy young adults. Remote preconditioning increases endothelial reactivity in healthy and hypertensive elderly. The potential clinical relevance of this finding deserves consideration.

Ageing and COPD affect different domains of nutritional status: the ECCE study.

Chronic obstructive pulmonary disease (COPD) and ageing may contribute to malnutrition. We aimed to explore whether COPD and ageing determine malnutrition in different manners. 460 stable COPD outpatients (376 males and 84 females) from the Extrapulmonary Consequences of COPD in the Elderly (ECCE) study database were investigated (age 75.0±5.9 yrs; forced expiratory volume in 1 s 54.7±18.3% predicted). Nutritional status was evaluated using the Mini Nutritional Assessment® (MNA) questionnaire. From the MNA, three scores exploring the domains of the nutritional status were calculated: body composition, energy intake and body functionality scores. Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages were negatively correlated with five MNA items exploring mobility, patient's perception of own nutrition and health status, and arm and calf circumferences (lowest Spearman's rho (rs)=-0.011; highest p=0.039). GOLD stages were independently correlated with body composition and body functionality scores (model r2=0.073). Age was negatively correlated with four MNA items exploring loss of appetite, fluid intake, mobility and autonomy in daily life (lowest rs=-0.013; highest p=0.030). Age was independently correlated with body functionality score (model r2=0.037). Severe COPD and ageing are independent and probably concurrent conditions leading to malnutrition. The MNA questionnaire allows a valuable insight into the complexity of components of nutritional status and may provide useful clues for treatment strategies.

Health care for older people in Italy: The U.L.I.S.S.E. Project (Un link informatico sui servizi sanitari esistenti per l'anziano - a computerized network on health care services for older people).

OBJECTIVES: The U.L.I.S.S.E. study is aimed at describing older patients who are cared for in hospitals, home care or nursing homes in Italy. DESIGN: The U.L.I.S.S.E. study is an observational multicenter prospective 1-year study. SETTING: Overall, 23 acute geriatric or internal medicine hospital units, 11 home care services and 31 nursing homes participated in the study. MEASUREMENTS: The patient's evaluation was performed using comprehensive geriatric assessment instruments, i.e. the interRAI Minimum Data Set, while data on service characteristics were recorded using ad-hoc designed questionnaires. RESULTS: The older subjects who are in need of acute and long term care in Italy have similar characteristics: their mean age is higher than 80 years, they have a high level of disability in ADL, an important multimorbidity, and are treated with several drugs. The prevalence of cognitive impairment is particularly high in nursing homes, where almost 70% of residents suffer from it and 40% have severe cognitive impairment. On the other hand, there is a shortage of health care services, which are heterogeneous and fragmented. CONCLUSIONS: Health care services for older people in Italy are currently inadequate to manage the complexity of the older patients. An important effort should be undertaken to create a more integrated health care system.

Covalently immobilized RGD gradient on PEG hydrogel scaffold influences cell migration parameters.

Understanding the influence of a controlled spatial distribution of biological cues on cell activities can be useful to design "cell instructive" materials, able to control and guide the formation of engineered tissues in vivo and in vitro. To this purpose, biochemical and mechanical properties of the resulting biomaterial must be carefully designed and controlled. In this work, the effect of covalently immobilized RGD peptide gradients on poly(ethylene glycol) diacrylate hydrogels on cell behaviour was studied. We set up a mechanical device generating gradients based on a fluidic chamber. Cell response to RGD gradients with different slope (0.7, 1 and 2 mM cm(-1)) was qualitatively and quantitatively assessed by evaluating cell adhesion and, in particular, cell migration, compared to cells seeded on hydrogels with uniform distribution of RGD peptides. To evaluate the influence of RGD gradient and to exclude any concentration effect on cell response, all analyses were carried out in a specific region of the gradients which displayed the same average concentration of RGD (1.5 mM). Results suggest that cells recognize the RGD gradient and adhere onto it assuming a stretched shape. Moreover, cells tend to migrate in the direction of the gradient, as their speed is higher than that of cells migrating on hydrogels with a uniform distribution of RGD and increases by increasing RGD gradient steepness. This increment is due to an augmentation of bias speed component of the mean squared speed, that is, the drift of the cell population migrating on the anisotropic surface provided by the RGD gradient.

Age-related pharmacokinetic and pharmacodynamic changes and related risk of adverse drug reactions.

Aging is known to be associated with an increased prevalence of multiple chronic diseases, which frequently causes the use of complex therapeutic regimens. The aging process is characterized by relevant changes in drug handling, physiological reserve, and pharmacodynamic response. Hepatic drug clearance of several drugs decreases with aging, mainly due to reduced blood flow, and hepatocyte mass. Renal function also declines with aging, mainly due to sclerotic changes in the glomeruli. Furthermore, due to reduced muscle mass, older subjects frequently have depressed glomerular filtration rate despite normal serum creatinine, and such a concealed renal insufficiency may impact significantly the clearance of hydrosoluble drugs. Changes in pharmacodynamics are also well documented in the cardiovascular and nervous system. Age-related changes in pharmacokinetics and pharmacodynamics, together with comorbidity and polypharmacy, make elderly patients at special risk for adverse drug reactions, which in turn are cause of relevant health burden and costs. Selected measures can assist in preventing or detecting timely such adverse events.

Synthesis of novel MMT/acyl-protected nucleo alanine monomers for the preparation of DNA/alanyl-PNA chimeras.

Alanyl-peptide nucleic acid (alanyl-PNA)/DNA chimeras are oligomers envisaged to be beneficial in efficient DNA diagnostics based on an improved molecular beacon concept. A synthesis of alanyl-PNA/DNA chimera can be based on the solid phase assembly of the oligomer with mixed oligonucleotide/peptide backbone under DNA synthesis conditions, in which the nucleotides are introduced as phosphoramidites, whereas the nucleo amino acids make use of the acid labile monomethoxytrityl (MMT) group for temporary protection of the alpha-amino groups and acyl protecting groups for the exocyclic amino functions of the nucleobases. In this work, we realized for the first time the synthesis of all four MMT/acyl-protected nucleo alanines, achieved by deprotection/reprotection of the newly synthesized Boc/acyl intermediates, useful monomers for the obtainment of (alanyl-PNA)/DNA chimeras by conditions fully compatible with the standard phosphoramidite DNA synthesis strategy.

Synthesis, characterization and hybridization studies of an alternate nucleo-epsilon/gamma-peptide: complexes formation with natural nucleic acids.

In order to develop new oligodeoxyribonucleotide (ODN) analogs to be used in biotechnological applications, we report here the synthesis, characterization and nucleic acid binding studies of novel nucleopeptides, that we called epsilon-lys/gamma-dabPNAs, containing a backbone of alternated L-diaminobutyric acid and L-lysine moieties. Exploring the hybridization properties of the new ODN analog, we found, by circular dichroism and UV spectroscopies, that a homothymine epsilon-lys/gamma-dabPNA hexamer binds both DNA and RNA of complementary sequence. Furthermore, human serum stability assays on the alternate nucleopeptide evidenced a noteworthy degradation resistance. These results encourage us to deepen the knowledge of this analog, in order to evaluate its possible use in antigene/antisense or diagnostic applications.

The neuroblastoma tumour-suppressor TrkAI and its oncogenic alternative TrkAIII splice variant exhibit geldanamycin-sensitive interactions with Hsp90 in human neuroblastoma cells.

Hsp90 chaperones stabilize many tyrosine kinases including several oncogenes, which are inhibited or induced to degrade by the Hsp90 inhibitor geldanamycin (GA). As a consequence, GA has been developed for future chemotherapeutic use in several tumour types including neuroblastoma (NB). Alternative splicing of the neurotrophin receptor tyrosine kinase TrkA may have a pivotal function in regulating NB behaviour, with reports suggesting that tumour-suppressing signals from TrkA may be converted to oncogenic signals by stress-regulated alternative TrkAIII splicing. Within this context, it is important to know whether Hsp90 interacts with TrkA variants in NB cells and how GA influences this. Here, we report that both TrkAI and TrkAIII are Hsp90 clients in human NB cells. TrkAI exhibits GA-sensitive interaction with Hsp90 required for receptor endoplasmic reticulum export, maturation, cell surface stabilization and ligand-mediated activation, whereas TrkAIII exhibits GA-sensitive interactions with Hsp90 required for spontaneous activity and to a lesser extent stability. We show that GA inhibits proliferation and induces apoptosis of TrkAI expressing NB cells, whereas TrkAIII reduces the sensitivity of NB cells to GA-induced elimination. Our data suggest that GA-sensitive interactions with Hsp90 are critical for both TrkAI tumour suppressor and TrkAIII oncogenic function in NB and that TrkAIII expression exerts a negative impact on GA-induced NB cell eradication, which can be counteracted by a novel TrkAIII-specific peptide nucleic acid inhibitor.