SUMMARY Growth differentiation factor 11 (GDF11), a TGF-beta super-family member, is highly homologous to myostatin and essential for embryonic patterning and organogenesis. Reports of GDF11 effects on adult tissues are conflicting, with some describing anti-aging and pro-regenerative activities on the heart and skeletal muscle while others opposite or no effects. Herein, we sought to determine the in vivo cardiac and skeletal muscle effects of excess GDF11. Mice were injected with GDF11 secreting cells, an identical model to that used to initially identify the in vivo effects of myostatin. GDF11 exposure in mice induced whole body wasting and profound loss of function in cardiac and skeletal muscle over a 14-day period. Loss of cardiac mass preceded skeletal muscle loss. Cardiac histologic and echocardiographic evaluation demonstrated loss of ventricular muscle wall thickness, decreased cardiomyocyte size and decreased cardiac function 10 days following initiation of GDF11 exposure. Changes in skeletal muscle after GDF11 exposure were manifest at day 13 and associated with wasting, decreased fiber size, and reduced strength. Changes in cardiomyocytes and skeletal muscle fibers were associated with activation of SMAD2, the ubiquitin-proteasome pathway and autophagy. GDF11 over administration in vivo results in cardiac and skeletal muscle loss, dysfunction and death. Serum levels of GDF11 by Western blotting were 1.5 fold increased over controls. Although GDF11 effects in vivo are likely dose, route, and duration dependent, its physiologic changes are similar to myostatin and other Activin receptors ligands. These data support that GDF11, like its other closely related TGF-beta family members, induces loss of cardiac and skeletal muscle mass and function.

Among the different DNA anomalies that can be present in the male gamete, DNA fragmentation is the most frequent, particularly in infertile subjects. There is now consistent evidence that a sperm containing fragmented DNA can be alive, motile, morphologically normal and able to fertilize an oocyte. There is also evidence that the oocyte is able to repair DNA damage; however, the extent of this repair depends on the type of DNA damage present in the sperm, as well as on the quality of the oocyte. Thus, it is important to understand the possible consequences of sperm DNA fragmentation (SDF) for embryo development, implantation, pregnancy outcome and the health of progeny conceived, both naturally and by assisted reproductive technology (ART). At present, data on the consequences of SDF for reproduction are scarce and, in many ways, inconsistent. The differences in study conclusions might result from the different methods used to detect SDF, the study design and the inclusion criteria. Consequently, it is difficult to decide whether SDF testing should be carried out in fertility assessment and ART. It is clear that there is an urgent need for the standardisation of the methods and for additional clinical studies on the impact of SDF on ART outcomes.

Background and aims Despite anticoagulation, usually with heparin, mortality for thromboembolic events in COVID-19 remains high. Clinical efficacy of heparin is due to its interaction with antithrombin (AT) that may be decreased in COVID-19. Therefore, we correlated AT levels with outcomes of COVID-19. Methods and results We recruited 49 consecutive patients hospitalized for COVID-19. AT levels were significantly lower in 16 non-survivors than in 33 survivors (72.2 ± 23.4 versus 94.6 ± 19.5%; p = 0.0010). A multivariate Cox regression analysis showed that low AT (levels below 80%) was a predictor of mortality (HR:3.97; 95%CI:1.38 to 11.43; p = 0.0103). BMI was the only variable that showed a significant difference between patients with low and those with normal AT levels (32.9 ± 7.9 versus 27.5 ± 5.9%; p = 0.0104). AT levels were significantly lower in obese patients than in subjects with normal weight or overweight (77.9 ± 26.9 versus 91.4 ± 26.9 versus 91.4 ± 17.1%; p = 0.025). An inverse correlation between AT levels and BMI was documented (r:-0.33; p = 0.0179). Conclusions Our data first suggest that AT is strongly associated with mortality in COVID-19. In addition, AT may be the link between obesity and a poorer prognosis in patients with COVID-19. Other studies should confirm whether AT may become a prognostic marker and a therapeutic target in COVID-19.

BackgroundCancer-associated cachexia and muscle wasting are considered key determinants of cancer-related death and reduction in the quality of life of cancer patients. A crucial link has been established between activin signaling and skeletal muscle atrophy-hypertrophy.We previously showed that activin-βC, a novel activin-A antagonist, is a tumor modulator that abolishes the cancer-associated cachexia in a mouse genetic model of gonadal tumorigenesis, in which the normal balance of inhibin/activin signalling is disrupted by a targeted mutation in the Inha gene (inhibin α-KO mouse). This study aimed to identify the molecular mechanism by which activin-βC increases survival and abolishes cancer-associated cachexia in α-KO mice. We hypothesized that overexpression of activin-βC modulates the cachexia phenotype by antagonizing the activin signaling pathway and repressing muscle wasting via the ubiquitin-proteasome and the autophagic-lysosomal degradation pathways.MethodsMale and female ActC++, α-KO, and α-KO/ActC++ mice and WT littermate controls were studied. Western blot analysis for the specific E3 ubiquitin ligases, atrogin-1 and MuRF1, markers of the autophagic-lysosomal pathway, Beclin-1, p62, and LC3A/B, effectors Smad-2, Smad-3 and myostatin was performed in the gastrocnemius of age-matched mice. Histopathology of the gastrocnemius and survival analysis were also conducted in animals from the same breeding cohort. Serum levels of activin-A, inflammatory cytokines, hormonal profile, and bone density were also assessed.ResultsIncreased levels of atrogin-1, MuRF-1, Beclin-1, p62, LC3A/B-I, Smad-2 and serum levels of activin-A were noted in the α-KO mice. These mice developed gonadal cancers followed by severe weight loss, and reduced survival. Overexpression of activin- βC antagonized the activin signaling cascade, attenuating the ubiquitin-proteasome and the autophagic-lysosomal degradation pathways, and reduced serum levels of activin-A. α-KO/ActC++ mice displayed a less aggressive cachectic phenotype, reduced tumor weight, and prolonged survival.ConclusionOur findings show for the first time a specific effect of activin-βC on muscle wasting and transcription factors involved in muscle protein degradation. The study indicates that activin-βC may be a novel therapy to abrogate cancer-associated weight loss and prolong survival.

Activins are involved in the regulation of a diverse range of physiological processes including development, reproduction, and fertility, and have been implicated in the progression of cancers. Bioactivity is regulated by the inhibin α‐subunit and by an activin‐binding protein, follistatin. The activin‐βC subunit was not considered functionally significant in this regard due to an absence of phenotype in knockout mice. However, activin‐βC forms heterodimers with activin‐βA and activin‐C antagonizes activin‐A in vitro. Thus, it is proposed that overexpression, rather than loss of activin‐βC, regulates activin‐A bioactivity. In order to prove biological efficacy, inhibin α‐subunit knockout mice (α‐KO) were crossed with mice overexpressing activin‐βC (ActC++). Deletion of inhibin leads to Sertoli and granulosa cell tumours, increased activin‐A, and cancer‐associated cachexia. Therefore, cachexia and reproductive tumour development should be modulated in α‐KO/ActC++ mice, where excessive activin‐A is the underlying cause. Accordingly, a reduction in activin‐A, no significant weight loss, and reduced incidence of reproductive tumours were evident in α‐KO/ActC++ mice. Overexpression of activin‐βC antagonized the activin signalling cascade; thus, the tumourigenic effects of activin‐A were abrogated. This study provides proof of the biological relevance of activin‐βC. Being a regulator of activin‐A, it is able to abolish cachexia and modulate reproductive tumour development in α‐KO mice.