We designed a phase II, open-label study to evaluate the efficacy, tolerability, safety, and pharmacokinetics of orally doxycycline (100 mg BID) and tauroursodeoxycholic acid (TUDCA) (250 mg three times/day) administered continuously for 12 months. Primary endpoint is response rate defined as nonprogression of the neuropathy and of the cardiomyopathy. Since July 2010, we enrolled 20 patients. Seventeen patients have hereditary ATTR, two patients have senile systemic amyloidosis, and one is a domino recipient. Seven patients completed 12-month treatment, 10 completed 6-month treatment, two discontinued because of poor tolerability, and one is lost at follow-up. No serious adverse events were registered. No clinical progression of cardiac involvement was observed. The neuropathy (Neuropathy Impairment Score in the Lower Limbs [NIS-LL] and Kumamoto score) remained substantially stable over 1 year. These preliminary data indicate that the combination of Doxy-TUDCA stabilizes the disease for at least 1 year in the majority of patients with an acceptable toxicity profile.

Great interest is currently being devoted to the development of nanoparticles (NPs) for biomedical purposes, designed to improve the pharmacokinetic profile of their cargos (either imaging probes or drugs) and to enhance the specific targeting at the disease site. Recent works suggest that Surface Plasmon Resonance (SPR), widely used for the analysis of biomolecular interactions, represents a technique of choice for rapid and quantitative analyses of the interaction between NPs—functionalized with specific ligands—and their putative biological targets. Moreover, SPR can provide important details on the formation and the role of the protein “corona”, i.e., the protein layer which coats NPs once they come into contact with biological fluids. These novel applications of SPR sensors may be very useful to characterize, screen and develop nanodevices for biomedical purposes.

Repurposing doxycycline for the treatment of amyloidosis has recently been put forward based on the anti-aggregating and anti-inflammatory properties of this drug. Most of the investigations on the therapeutic potential of doxycycline for neurodegenerative amyloidosis, e.g. prion and Alzheimer disease (AD), are carried out in mouse models but, surprisingly, no data are available as regards the concentrations reached in the brain after systemic administration. We filled this gap by analysing the pharmacokinetic profile of doxycycline in plasma and brain after single and repeated intraperitoneal injections of 10 and 100 mg/kg, in wild-type mice and the APP23 mouse model of the AD. The main outcomes of our study are: i) peak plasma concentrations ranged 2-10 μg/mL, superimposable to those in humans; ii) brain-to-plasma ratio was ~0.2, comparable to the CSF/serum ratios in humans; iii) brain C_max, 4-6 h after a single dose, was ~0.5 μM (10 mg/kg) and ~5 μM (100 mg/kg). Notably, these concentrations are lower than those required for the drug9s anti-aggregating properties as observed in cell-free studies, suggesting that other features underlie the positive cognitive effects in AD mice; iv) elimination half-life was shorter than in humans (3-6h vs 15-30h), therefore no significant accumulation was observed in mouse brain following repeated treatments; v) there were no differences between doxycycline concentrations in brain areas of age-matched wild-type and APP23 mice. These data are useful for planning preclinical studies with translational validity, and to identify the mechanism(s) of action underlying the central in vivo effects of doxycycline more reliably.

Pulmonary arterial hypertension (PAH) reflects abnormal pulmonary vascular resistance and causes right ventricular (RV) hypertrophy. Enhancement of the late sodium current (I_NaL) may result from hypertrophic remodelling. The study tests whether: (i) constitutive I_NaL enhancement may occur as part of PAH-induced myocardial remodelling; (ii) ranolazine (RAN), a clinically available I_NaL blocker, may prevent constitutive I_NaL enhancement and PAH-induced myocardial remodelling. PAH was induced in rats by a single monocrotaline (MCT) injection [60 mg/kg intraperitoneally (i.p.)]; studies were performed 3 weeks later. RAN (30 mg/kg bid i.p.) was administered 48 h after MCT and washed-out 15 h before studies. MCT increased RV systolic pressure and caused RV hypertrophy and loss of left ventricular (LV) mass. In the RV, collagen was increased; myocytes were enlarged with T-tubule disarray and displayed myosin heavy chain isoform switch. I_NaL was markedly enhanced; diastolic Ca²⁺ was increased and Ca²⁺ release was facilitated. K⁺ currents were down-regulated and APD was prolonged. In the LV, I_NaL was enhanced to a lesser extent and cell Ca²⁺ content was strongly depressed. Electrical remodelling was less prominent than in the RV. RAN completely prevented I_NaL enhancement and limited most aspects of PAH-induced remodelling, but failed to affect in vivo contractile performance. RAN blunted the MCT-induced increase in RV pressure and medial thickening in pulmonary arterioles. PAH induced remodelling with chamber-specific aspects. RAN prevented constitutive I_NaL enhancement and blunted myocardial remodelling. Partial mechanical unloading, resulting from an unexpected effect of RAN on pulmonary vasculature, might contribute to this effect.