BackgroundEarly revascularization of ischemic organs is key to improving outcomes, yet consequent reperfusion injury may be harmful. Reperfusion injury is largely attributed to excess mitochondrial production of reactive oxygen species (ROS). Sulfide inhibits mitochondria and reduces ROS production. Ammonium tetrathiomolybdate (ATTM), a copper chelator, releases sulfide in a controlled and novel manner, and may offer potential therapeutic utility.Methods and findingsIn vitro, ATTM releases sulfide in a time-, pH-, temperature-, and thiol-dependent manner. Controlled sulfide release from ATTM reduces metabolism (measured as oxygen consumption) both in vivo in awake rats and ex vivo in skeletal muscle tissue, with a superior safety profile compared to standard sulfide generators. Given intravenously at reperfusion/resuscitation to rats, ATTM significantly reduced infarct size following either myocardial or cerebral ischemia, and conferred survival benefit following severe hemorrhage. Mechanistic studies (in vitro anoxia/reoxygenation) demonstrated a mitochondrial site of action (decreased MitoSOX fluorescence), where the majority of damaging ROS is produced.ConclusionsThe inorganic thiometallate ATTM represents a new class of sulfide-releasing drugs. Our findings provide impetus for further investigation of this compound as a novel adjunct therapy for reperfusion injury.

Myeloma bone disease results from an uncoupling of osteoclastic resorption and osteoblastic bone formation, but early changes in osteogenic function remain poorly defined. We used the KMS12BM xenograft model to investigate cellular and molecular events at early and late stages of disease. Lytic lesions and changes in osteoblast and osteoclast numbers occur late (8 weeks), however, micro-computed tomography of femora revealed significant reduction in bone volume at earlier disease stages (3 weeks) when tumour burden is low. Calcein labelling demonstrated reduced mineralization and bone formation at 3 weeks, suggesting functional impairment despite preserved osteoblast numbers. Osteo-progenitors from compact bone increased early (1 week), but fell at 3 weeks and were profoundly suppressed by 8 weeks. Exposure of osteoblast progenitors to multiple myeloma (MM) cells in vitro induced cell cycling, suggesting a mechanistic basis for early expansion of osteo-progenitors. We observed temporal changes in chemokine, osteogenic and osteoclastogenic genes in the stromal compartment. Notably, an early rise in CCL3 may underlie functional changes in mature osteoblasts at 3 weeks. Our data indicate that MM has distinct effects on mature osteoblasts and immature osteo-progenitors. Our findings argue for early clinical intervention to prevent bone changes that ultimately lead to the development of osteolytic disease.

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Abstract Improving outcomes in multiple myeloma will involve not only development of new therapies but also better use of existing treatments. We performed RNA sequencing on samples from newly diagnosed patients enrolled in the phase 2 PADIMAC (Bortezomib, Adriamycin, and Dexamethasone Therapy for Previously Untreated Patients with Multiple Myeloma: Impact of Minimal Residual Disease in Patients with Deferred ASCT) study. Using synthetic annealing and the large margin nearest neighbor algorithm, we developed and trained a 7-gene signature to predict treatment outcome. We tested the signature in independent cohorts treated with bortezomib- and lenalidomide-based therapies. The signature was capable of distinguishing which patients would respond better to which regimen. In the CoMMpass data set, patients who were treated correctly according to the signature had a better progression-free survival (median, 20.1 months vs not reached; hazard ratio [HR], 0.40; confidence interval [CI], 0.23-0.72; P = .0012) and overall survival (median, 30.7 months vs not reached; HR, 0.41; CI, 0.21-0.80; P = .0049) than those who were not. Indeed, the outcome for these correctly treated patients was noninferior to that for those treated with combined bortezomib, lenalidomide, and dexamethasone, arguably the standard of care in the United States but not widely available elsewhere. The small size of the signature will facilitate clinical translation, thus enabling more targeted drug regimens to be delivered in myeloma.