Preemptive antiviral therapy in lung transplantation from hepatitis C donors results in a rapid and sustained virologic response

Objective

The study objective was to assess the safety and efficacy of a preemptive direct-acting antiviral therapy in lung transplants from hepatitis C virus donors to uninfected recipients.

Methods

This study is a prospective, open-label, nonrandomized, pilot trial. Recipients of hepatitis C virus nucleic acid test positive donor lungs underwent preemptive direct-acting antiviral therapy with glecaprevir 300 mg/pibrentasvir 120 mg for 8 weeks from January 1, 2019, to December 31, 2020. Recipients of nucleic acid test positive lungs were compared with recipients of lungs from nucleic acid test negative donors. Primary end points were Kaplan-Meier survival and sustained virologic response. Secondary outcomes included primary graft dysfunction, rejection, and infection.

Results

Fifty-nine lung transplantations were included: 16 nucleic acid test positive and 43 nucleic acid test negative. Twelve nucleic acid test positive recipients (75%) developed hepatitis C virus viremia. Median time to clearance was 7 days. All nucleic acid test positive patients had undetectable hepatitis C virus RNA by week 3, and all alive patients (n = 15) remained negative during follow-up with 100% sustained virologic response at 12 months. One nucleic acid test positive patient died of primary graft dysfunction and multiorgan failure. Three of 43 nucleic acid test negative patients (7%) had hepatitis C virus antibody positive donors. None of them developed hepatitis C virus viremia. One-year survival was 94% for nucleic acid test positive recipients and 91% for nucleic acid test negative recipients. There was no difference in primary graft dysfunction, rejection, or infection. One-year survival for nucleic acid test positive recipients was similar to a historical cohort of the Scientific Registry of Transplant Recipients (89%).

Conclusions

Recipients of hepatitis C virus nucleic acid test positive lungs have similar survival as recipients of nucleic acid test negative lungs. Preemptive direct-acting antiviral therapy results in rapid viral clearance and sustained virologic response at 12 months. Preemptive direct-acting antiviral may partially prevent hepatitis C virus transmission.

Hypophosphite: A Review

Efforts to find a suitable sparing agent for nitrite in cured meat products have brought sodium hypophosphite (SHP) to the attention of the scientific community. Hypophosphites were introduced in the mid 1800s as a cure for tuberculosis, but recent reports have suggested SHP could possess antibotulinal and antimicrobial properties. Sodium hypophosphite has good potential as an antimicrobial food ingredient and it is Generally Recognized As Safe (GRAS). This review summarizes SHP chemistry, history, toxicology, regulatory status, applications, and antimicrobial properties.

Gonadotropin-releasing hormone binding and activation of enriched population of pituitary gonadotrophs

The properties of GnRH receptors were analyzed in isolated rat pituitary cells by binding studies with the labeled GnRH agonist, [125I]iodo-[D-Ser(tBu)6]des-Gly10-GnRH-N-ethylamide. The concentration of GnRH-binding sites in pituitary cells from immature female rats was twice as high as in cells from adult females. Electron-microscopic immunocytochemistry revealed twice as many gonadotrophs in the immature rat pituitary, indicating that gonadotrophs from immature and mature female rats contain the same number of binding sites. An enriched population of gonadotrophs prepared from immature female rat pituitaries by velocity sedimentation at unit gravity contained 77% of the total radioimmunoassayable LH, and 71% of the total GnRH receptors. A second population of small, poorly granulated gonadotrophs was distributed among the cells of other fractions of the gradient, and could be detected only by immunocytochemistry. The smaller, possibly immature, gonadotrophs did not contain a measurable number of GnRH receptors. When incubated with the cells recovered from the gradient, GnRH stimulated LH release only in the mature gonadotroph-enriched fraction, and not in other regions of the gradient. These results indicate that GnRH interacts preferentially with gonadotrophs in the pituitary. The findings also suggest that functional heterogeneity exists among pituitary gonadotrophs, and that GnRH binds to and activates only the mature gonadotrophs which exhibit the highest LH-storage capacity.

Calcium-dependent actions of gonadotropin-releasing hormone on pituitary guanosine 3',5'-monophosphate production and gonadotropin release

The effects of gonadotropin-releasing hormone (GnRH) on cGMP production and LH release in cultured rat pituitary cells are markedly dependent upon the extracellular calcium concentration. The absence of calcium from incubation media caused almost complete loss of the GnRH effects on cGMP production and LH release but did not change the stimulation of cAMP accumulation by GnRH in the pituitary of the adult male rat. In female rat pituitary cells, reduction of the extracellular calcium concentration increased the concentration of GnRH required to produce half-maximal LH release and decreased the maximal gonadotropin output but had no significant effect on basal LH release. The divalent cation ionophore A23187 stimulated LH release, and this action was dependent on extracellular calcium. Both GnRH and A23187 were found to have maximal effects when the calcium concentration was 0.6 mM, and their actions were not additive. The calcium antagonists, verapamil and lanthanum, caused concentration-dependent inhibition of the actions of GnRH, with half-maximal blockade values of 10(-5) and 3 X 10(-6) M, respectively, and had no effect on basal LH release. The binding of a radioiodinated GnRH analog, [D-Ser(t-Bu)6]des-Gly10-GnRH-N-ethylamide, to pituitary GnRH receptors was unchanged in the absence of extracellular calcium. These observations demonstrate that stimulation of pituitary cGMP production and LH release by GnRH is dependent on extracellular calcium. The site at which calcium is required during GnRH action is at a postreceptor locus before cGMP formation.