Conjugation of small interfering RNA (siRNA) to an asialoglycoprotein receptor ligand derived from N-acetylgalactosamine (GalNAc) facilitates targeted delivery of the siRNA to hepatocytes in vitro and in vivo. The ligands derived from GalNAc are compatible with solid-phase oligonucleotide synthesis and deprotection conditions, with synthesis yields comparable to those of standard oligonucleotides. Subcutaneous (SC) administration of siRNA−GalNAc conjugates resulted in robust RNAi-mediated gene silencing in liver. Refinement of the siRNA chemistry achieved a 5-fold improvement in efficacy over the parent design in vivo with a median effective dose (ED 50 ) of 1 mg/kg following a single dose. This enabled the SC administration of siRNA−GalNAc conjugates at therapeutically relevant doses and, importantly, at dose volumes of ≤1 mL. Chronic weekly dosing resulted in sustained dose-dependent gene silencing for over 9 months with no adverse effects in rodents. The optimally chemically modified siRNA−GalNAc conjugates are hepatotropic and long-acting and have the potential to treat a wide range of diseases involving liver-expressed genes.

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Ferroptosis is a non-apoptotic form of regulated cell death caused by the failure of the glutathione-dependent lipid-peroxide-scavenging network. FINO2 is an endoperoxide-containing 1,2-dioxolane that can initiate ferroptosis selectively in engineered cancer cells. We investigated the mechanism and structural features necessary for ferroptosis initiation by FINO2. We found that FINO2 requires both an endoperoxide moiety and a nearby hydroxyl head group to initiate ferroptosis. In contrast to previously described ferroptosis inducers, FINO2 does not inhibit system xc− or directly target GPX4, as do erastin and RSL3, respectively, or deplete GPX4 protein, as does FIN56. Instead, FINO2 causes both indirect loss of GPX4 enzymatic function and directly oxidizes iron, ultimately causing widespread lipid peroxidation. These findings suggest that endoperoxides such as FINO2 can initiate a multi-pronged mechanism of ferroptosis.

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BaCKgRoUND aND aIMS:Acute hepatic porphyria comprises a group of rare genetic diseases caused by mutations in genes involved in heme biosynthesis. Patients can experience acute neurovisceral attacks, debilitating chronic symptoms, and long-term complications. There is a lack of multinational, prospective data characterizing the disease and current treatment practices in severely affected patients. appRoaCH aND ReSUltS: EXPLORE is a prospective, multinational, natural history study characterizing disease activity and clinical management in patients with acute hepatic porphyria who experience recurrent attacks. Eligible patients had a confirmed acute hepatic porphyria diagnosis and had experienced ≥3 attacks in the prior 12 months or were receiving prophylactic treatment. A total of 112 patients were enrolled and followed for at least 6 months. In the 12 months before the study, patients reported a median (range) of 6 (0-52) acute attacks, with 52 (46%) patients receiving hemin prophylaxis. Chronic symptoms were reported by 73 (65%) patients, with 52 (46%) patients experiencing these daily. During the study, 98 (88%) patients experienced a total of 483 attacks, 77% of which required treatment at a health care facility and/or hemin administration (median [range] annualized attack rate 2.0 [0.0-37.0]). Elevated levels of hepatic δ-aminolevulinic acid synthase 1 messenger ribonucleic acid levels, δ-aminolevulinic acid, and porphobilinogen compared with the upper limit of normal in healthy individuals were observed at baseline and increased further during attacks. Patients had impaired quality of life and increased health care utilization. CoNClUSIoNS:Patients experienced attacks often requiring treatment in a health care facility and/or with hemin, as well as chronic symptoms that adversely influenced day-to-day functioning. In this patient group, the high disease burden and diminished quality of life highlight the need for novel therapies. (Hepatology 2020;71:1546-1558.A cute hepatic porphyria (AHP) comprises a group of rare metabolic diseases caused by mutations in genes encoding enzymes involved in heme biosynthesis. (1,2) The four types Abbreviations: AAR, annualized attack rate; AHP, acute hepatic porphyria; AIP, acute intermittent porphyria; ALA, δ-aminolevulinic acid; ALAS1, δ-aminolevulinic acid synthase 1; CKD, chronic kidney disease; eGFR, estimated glomerular filtration rate; EQ-5D-5L, EuroQoL 5-dimensions questionnaire 5-levels; HCP, hereditary coproporphyria; LC-MS/MS, liquid chromatography-tandem mass spectrometry; PBG, porphobilinogen; QoL, quality of life; ULN, upper limit of normal; VP, variegate porphyria.

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Computers and associated technology have become central to modern life. In a society where the population is rapidly ageing, the acceptance and utilisation of developing technologies by an older population is becoming increasingly important. This review highlights similarities and differences between the attitudes and acceptance of technology by older and younger people, leading to the conclusion that similar factors influence both age groups-hence, older people could well be taught to use technology in a similar manner to younger people. While all learners, irrespective of age, should receive sufficient time for training in a positive and supportive environment, this review suggests that due consideration ought to be given to the amount of time allowed for older users to learn new skills and the manner in which learners are treated in a positive and valued manner.

ObjectiveTo identify changes in the proteome associated with onset and progression of ATTRv amyloidosis, we performed an observational, case-controlled study which compared proteomes of patients with ATTRv amyloidosis and healthy controls.MethodsPlasma levels of >1,000 proteins were measured in patients with ATTRv amyloidosis with polyneuropathy who received either placebo or patisiran in the APOLLO study and in healthy controls. The impact of patisiran on the time profile of each protein was determined by linear mixed model at 0, 9, and 18 months. Neurofilament light chain (NfL) was further assessed using an orthogonal quantitative approach.ResultsLevels of 66 proteins were significantly changed with patisiran vs placebo, with NfL change most significant (p < 10−20). Analysis of changes in protein levels demonstrated that the proteome of patisiran-treated patients trended toward healthy controls at 18 months. Healthy controls' NfL levels were 4-fold lower than in patients with ATTRv amyloidosis with polyneuropathy (16.3 vs 69.4 pg/mL, effect: −53.1 pg/mL, 95% CI [–60.5 to −45.9]). NfL levels at 18 months increased with placebo (99.5 vs 63.2 pg/mL, 36.3 pg/mL, [16.5–56.1]) and decreased with patisiran treatment (48.8 vs 72.1 pg/mL, −23.3 pg/mL, [–33.4 to −13.1]) from baseline. At 18 months, improvement in modified Neuropathy Impairment Score +7 following patisiran significantly correlated with reduced NfL (R = 0.43, [0.29–0.55]).ConclusionsFindings suggest NfL may serve as a biomarker of nerve damage and polyneuropathy in ATTRv amyloidosis, may enable earlier diagnosis of patients with ATTRv amyloidosis, and facilitate monitoring of disease progression.Classification of evidenceThis study provides Class III evidence that NfL levels may enable earlier diagnosis of polyneuropathy in patients with ATTRv amyloidosis and facilitate monitoring of disease progression.