Sex differences in the aging human heart: decreased sirtuins, pro-inflammatory shift and reduced anti-oxidative defense.

Aging is associated with increased inflammation and alterations in mitochondrial biogenesis, which promote the development of cardiovascular diseases. Emerging evidence suggests a role for sirtuins, which are NAD+-dependent deacetylases, in the regulation of cardiovascular inflammation and mitochondrial biogenesis. Sirtuins are regulated by sex or sex hormones and are decreased during aging in animal models. We hypothesized that age-related alterations in cardiac Sirt1 and Sirt3 occur in the human heart and examined whether these changes are associated with a decrease in anti-oxidative defense, inflammatory state and mitochondrial biogenesis. Using human ventricular tissue from young (17-40 years old) and old (50-68 years old) individuals, we found significantly lower Sirt1 and Sirt3 expression in old female hearts than in young female hearts. Additionally, lower expression of the anti-oxidative protein SOD2 was observed in old female hearts than in young female hearts. Aging in female hearts was associated with a significant increase in the number of cardiac macrophages and pro-inflammatory cytokines, as well as NF-kB upregulation, indicating a pro-inflammatory shift. Aging-associated pathways in the male hearts were different, and no changes in Sirt1 and Sirt3 or cardiovascular inflammation were observed. In conclusion, the present study revealed a female sex-specific downregulation of Sirt1 and Sirt3 in aged hearts, as well as a decline in mitochondrial anti-oxidative defense and a pro-inflammatory shift in old female hearts but not in male hearts.

Why the study of the effects of biological sex is important. Commentary.

Biological sex significantly affects the presentation, outcome of treatment and progression of disease. However, the role of sex has yet underestimated consequences for physiology and pathology. We put forward that a better understanding of the effects of sex in pathophysiology and the underlying mechanisms is necessary. This may facilitate the identification of targets that respond to specific therapies, thereby contributing towards a more appropriate and individualised medical care for both men and women.

The peritoneum--an important factor for pathogenesis and pain generation in endometriosis.

Endometriosis (EM) is an oestrogen-dependent disease affecting 10-15 % of women during reproductive age. It is characterised by the presence of endometrial glands, stromal- and smooth muscle-like cells outside of the uterine cavity. Fifty to sixty per cent of women and teenage girls with pelvic pain suffer from EM. EM causes disability and compromises the quality of life in women and young girls significantly. Pain generation in EM is an intricate interplay of several factors such as the endometriotic lesions themselves and the pain-mediating substances, nerve fibres and cytokine-releasing immune cells such as macrophages. These interactions seem to induce a neurogenic inflammatory process. Recently published data demonstrated an increased peptidergic and decreased noradrenergic nerve fibre density in peritoneal lesions. These data could be substantiated by in vitro analyses demonstrating that the peritoneal fluids of patients suffering from EM induced an enhanced sprouting of sensory neurites from chicken dorsal root ganglia and decreased neurite outgrowth from sympathetic ganglia. These findings might be directly involved in the perpetuation of inflammation and pain. Furthermore, the evidence of EM-associated smooth muscle-like cells seems another important factor in pain generation. The peritoneal endometriotic lesion leads to reactions in the surrounding tissue and, therefore, is larger than generally believed. The identification of EM-associated nerve fibres and smooth muscle-like cells fuel discussions on the mechanisms of pain generation in EM, and may present new targets for innovative treatments.

Effects of Chronic D-Serine Elevation on Animal Models of Depression and Anxiety-Related Behavior.

NMDA receptors are activated after binding of the agonist glutamate to the NR2 subunit along with a co-agonist, either L-glycine or D-serine, to the NR1 subunit. There is substantial evidence to suggest that D-serine is the most relevant co-agonist in forebrain regions and that alterations in D-serine levels contribute to psychiatric disorders. D-serine is produced through isomerization of L-serine by serine racemase (Srr), either in neurons or in astrocytes. It is released by astrocytes by an activity-dependent mechanism involving secretory vesicles. In the present study we generated transgenic mice (SrrTg) expressing serine racemase under a human GFAP promoter. These mice were biochemically and behaviorally analyzed using paradigms of anxiety, depression and cognition. Furthermore, we investigated the behavioral effects of long-term administration of D-serine added to the drinking water. Elevated brain D-serine levels in SrrTg mice resulted in specific behavioral phenotypes in the forced swim, novelty suppression of feeding and olfactory bulbectomy paradigms that are indicative of a reduced proneness towards depression-related behavior. Chronic dietary D-serine supplement mimics the depression-related behavioral phenotype observed in SrrTg mice. Our results suggest that D-serine supplementation may improve mood disorders.

Evidence of neurotrophic events due to peritoneal endometriotic lesions.

To investigate the neurotrophic properties of endometriosis, as well as the involvement of neurotrophic factors in the development of chronic pelvic pain in patients with endometriosis, we performed a prospective clinical study. The presence of neurotrophins was investigated in the peritoneal fluid (PF) of patients with peritoneal endometriotic lesions or adenomyosis, as well as from women with non-endometriotic adhesions and from women without endometriosis/adenomyosis/adhesions. The PF from patients with peritoneal endometriotic lesions was divided in three groups: asymptomatic endometriosis, minimal pain and severe pain. PF from patients with adenomyosis or with non-endometriotic adhesions and the control group were divided in patients without pain and with pain. Neurotrophin expression in PF was analyzed using Elisa and the neuronal growth assay with cultured chicken sensory ganglia (dorsal-root-ganglia, DRG) and sympathetic ganglia. PF from women with peritoneal endometriotic lesions overexpress nerve growth factor (NGF) and neurotrophin-3 (NT-3), but not brain derived neurotrophic factor (BDNF), whereas the PF of women with adenomyosis or adhesions seems to express normal amounts of these factors. Neurotrophin expression did not differ among the pain groups. Furthermore, the PF from patients with peritoneal endometriotic lesions induced a strong sensory and a marginal sympathetic neurite outgrowth, while the PF from women with adenomyosis and non-endometriotic adhesions induced an outgrowth similar to the control group. The induced neurite outgrowth could only be inhibited in DRG incubated with peritoneal endometriotic lesions. Interestingly, the outgrowth of sympathetic ganglia was inhibited in all studied groups. The present study suggests that only peritoneal endometriotic lesions lead to an increased release of NGF and NT-3 into the PF and that NGF modulates the nerve fiber growth in endometriosis.

Neuroimmunomodulatory alterations in non-lesional peritoneum close to peritoneal endometriosis.

OBJECTIVES: An imbalance in the ratio of sensory to sympathetic nerve fibre (NF) density in peritoneal endometriotic lesions (pEL) has recently been demonstrated and leads to the assumption that this preponderance of the sensory pro-inflammatory milieu is a major cause of pain in endometriosis. Therefore, the density of sensory and sympathetic NFs was determined in distal unaffected peritoneum of endometriosis patients to be able to detect possible alterations in unaffected peritoneum. METHODS: In serial pEL sections (n = 40), lesional and matching unaffected peritoneum as well as healthy peritoneum (HP) from patients without endometriosis (n = 15) were immunohistochemically analysed to identify protein gene product 9.5-, substance P- and tyrosine hydroxylase-positive NFs (intact, sensory and sympathetic NFs, respectively). In addition, the amount of immune cell infiltrates and the expression of nerve growth factor (NGF) and interleukin (IL)-1ß in nerves of peritoneal endometriotic specimens were compared to those in the HP. RESULTS: The overall NF density in the non-lesional, unaffected peritoneum of endometriosis patients is significantly reduced in comparison to both HP and pEL, while sensory NFs remain the same; the sympathetic NF density is significantly decreased compared to HP, but is still higher than the density close to the pEL. Immune cell infiltrates as well as NGF and IL-1ß expression in nerves is significantly elevated in distal unaffected peritoneum in comparison to HP. CONCLUSION: The altered NF density in the non-lesional, unaffected peritoneum of endometriosis patients suggests new aspects in the understanding of the development of endometriosis and pain management in endometriosis.

Eutopic endometrium from women with endometriosis does not exhibit neurotrophic properties.

The role of neurotrophins in eutopic endometrium from endometriosis-patients was investigated in a prospective study using immunofluorescence-staining, Western blot and a neuronal growth assay. The nerve growth factor is expressed in primary endometrial cell culture from women with and without endometriosis. Western blot analysis of endometrial biopsies or uterine fluid from patients with and without endometriosis shows no difference in the neurotrophin expression. We could not find a difference between patients with and without endometriosis with regards to the neurite outgrowth of sensory ganglia when treated with conditioned cultured medium or uterine fluid. This result refutes the assumed neurotrophic properties of eutopic endometrium of patients with endometriosis.

Neurotrophin expression is not affected in uteri of women with adenomyosis.

To investigate the involvement of neurotrophins and nerve fibres in the pathogenesis of adenomyosis, we performed a retrospective, clinical study. Hysterectomy specimens from 40 patients with histologically proven adenomyosis and from 20 patients without adenomyosis or endometriosis were used for immunohistochemical analysis. In order to investigate neurotrophic properties in adenomyosis, the antibodies against nerve growth factor (NGF), neurotrophin 3 (NT-3), the high-affinity NGF receptor (TrkA), the low-affinity neurotrophin receptor (p75(NTR)), the neuronal marker S100 (for myelinated nerve fibres) and protein gene product 9.5 (PGP9.5; for intact nerve fibres) were used. There was no significant difference in the NGF, NT-3 and p75(NTR) expression in the myometrium or endometrium between the adenomyosis and the control group. The nerve fibre density (S100, PGP9.5 and p75(NTR)) did not significantly differ between the adenomyosis and control group, the nerve fibre density of the adenomyosis group was tendentially decreased when compared with the nonporous control group. The present study suggests that endometrial and uterine neurotrophin expression and endometrial innervation are not altered in adenomyosis; however, women with adenomyosis or with adenomyosis/endometriosis tendentially had less myometrial nerve fibres than the control group.

Overexpression of nerve growth factor in peritoneal fluid from women with endometriosis may promote neurite outgrowth in endometriotic lesions.

To investigate the role of the nerve growth factor (NGF) in the endometriosis-associated innervation in the development of endometriosis-associated symptoms, 41 peritoneal fluid samples (PF) from patients with surgically and histologically proven endometriosis and 20 PF from patients with other gynecologic conditions were analyzed with Western blot and a novel in vitro model using dorsal root ganglia (DRG) to show neuronal outgrowth; endometrial cells also were analyzed. The results suggest that the PF of endometriosis patients and endometriotic lesions have neurotropic properties, because the Western blot analysis and the cell culture stainings showed NGF expression, and the neurite outgrowth of DRG treated with PF of patients with endometriosis was significantly higher than when treated with PF of patients without endometriosis. Furthermore, blocking NGF with both anti-NGF and K252a leads to a significant decrease in neurite outgrowth.