Alejandra Figueroa

Background/Objectives: Ischemic stroke is a leading cause of death and disability, and neuroprotection therapies, or those that increase recovery, are not available. While the garlic-derived bioactive compound S-allyl cysteine (SAC) has shown neuroprotective properties, its subacute long-term effects remain underexplored, particularly in females. Methods: We evaluated whether SAC supports functional recovery after ischemia/reperfusion (IR), focusing on neurotrophin signaling, tropomyosin receptor kinase B (TrkB), protein kinase B (AKT), and extracellular signal-regulated kinase (ERK). Adult female Wistar rats underwent 1 h of ischemia and 15 days of reperfusion. SAC (100 mg/kg, i.p.) was administered at the onset of reperfusion and daily for 15 days. Motor and cognitive deficit tests were performed. Infarct area, Ki67, brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF), nerve growth factor (NGF), pTrkB, pAKT, and pERK levels were quantified in the cortex, striatum, and hippocampus. Results: MicroPET analysis revealed comparable glucose uptake between the IR and IR + SAC groups, indicating similar ischemic severity. SAC reduced infarct area (54.7%) and significantly improved motor deficits (53.9%), circling behavior (38.9%), and long-term memory compared with ischemia/reperfusion (IR) animals. SAC increased the proportion of Ki67-positive cells (4.3-fold in the cortex and 1.8-fold in the striatum) and enhanced neurotrophin levels, NGF (cortex), BDNF (cortex and striatum), VEGF (striatum), pTrkB, pAKT, and pERK (cortex and striatum). Conclusions: SAC supports post-ischemic recovery, improving motor performance and preserving long-term recognition memory, effects that could be associated with increased cell proliferation, neurotrophin levels, and activation of the TrkB, AKT, and ERK pathways.

We studied the cellular organization of the piriform network [comprising the piriform cortex (PC) and endopiriform nucleus (EP)] of the ferret (Mustela putorius)—a highly excitable region prone to seizures—and, more specifically, the distribution and morphology of different types of gamma-aminobutyric acid (GABA)ergic neurons, and the distribution and ratio of glutamatergic and GABAergic boutons, and we compared our findings to those in primary visual area 17, and secondary areas 18 and 19. We accomplished this by using cytochrome oxidase and immunohistochemistry for mature neuronal nuclei (NeuN), GABAergic neurons [glutamic acid decarboxylase-67 (GAD67), calretinin (CR) and parvalbumin (PV)], and for excitatory (vesicular glutamate transporter 1; VGluT1) and inhibitory (vesicular GABA transporter; VGAT) boutons. In the ferret, the cellular organization of the piriform network is similar to that described in other species such as cats, rats and opossums although some differences also exist. GABAergic immunolabeling showed similarities between cortical layers I–III of the PC and visual areas, such as the relative distribution of GABAergic neurons and the density and area of VGluT1- and VGAT-immunoreactive boutons. However, multiple differences between the piriform network and visual areas (layers I–VI) were found, such as the percentage of GABAergic neurons with respect to the total number of neurons and the ratio of VGluT1- and VGAT-immunoreactive boutons. These findings are relevant to better understand the high excitability of the piriform network.

Mistletoes are hemi-parasitic plants widely distributed around the world, used in folk medicine to treat many diseases including diabetes, hypertension, menopausal syndrome and as complementary or adjuvant treatment for cancer. The objective of the present work was the evaluation of oestrogenic activity of hydromethanolic extract of mistletoe Struthanthus venetus dried leaves (StvHME), to evaluate its potential benefits in menopause and breast cancer, which have not been reported so far. Uterotrophic activity was evaluated in immature female CD1 mice, administering StvHME (10, 100 and 500 mg/kg) for three consecutive days compared to the natural hormone 17β-oestradiol (E2, 10 μg/kg). Comparison of the MCF-7 positive oestrogen receptor human breast adenocarcinoma cell proliferation in the presence of StvHME (0.5, 5 and 50 μg/ml) or E2 (10-12-10-10M) related to untreated control cells was assessed using MTT cell viability assay. StvHME, produced biphasic effects in mice uteri; low doses (10 mg/kg) decreased uterine weight (15-38%; p<0.05), while a higher dose (500 mg/kg) increased uterine weight (28-36%; p<0.05). StvHME concentrations tested inhibited MCF-7 cell proliferation, contrasting with E2 which increased it. StvHME (50 μg/ml) antagonized the proliferative response to E2 (10-12 to 10-10 M) behaving as an anti-oestrogen. The antiproliferative response of StvHME (50 μg/ml) showed synergism with the oestrogen antagonists Tamoxifen and Fulvestrant (ICI 182,780). Our results suggest the presence of oestrogenic and anti-oestrogenic components in the StvHME that could be acting through the oestrogen ERα and ERβ receptors. Therefore, StvHME has potential utility as a complementary therapy for breast cancer. Key words: mistletoe, Struthanthus venetus, MCF-7 cells, oestrogenicity, anti-oestrogenic, anti-cancer, menopause.

The 17β‐aminoestrogens (AEs) prolame, butolame and pentolame are weakly oestrogenic in rodents and display anticoagulant properties in contrast to oestradiol (E₂) which presents pro‐coagulant effects, potentially thrombogenic. They possess anti‐anxiety and antidepressive properties, being good candidates for menopausal hormone therapy (MHT). Their capability to induce proliferation of MCF‐7 human breast cancer cells, in which proliferative rate depends on oestrogens, has not been explored; thus, the aim of this work was to characterize it. AEs’ proliferation properties were evaluated compared with E₂ in MCF‐7 carcinoma cell line cultures using established methods. Receptor mediation on cell proliferation was studied by co‐incubating them with the oestrogen receptor antagonists tamoxifen, ICI 182,780 and the selective antagonists MPP (ERα) and PHTPP (ERβ). E₂ and AEs increased MCF‐7 cell proliferation; their proliferative effect was between 1.5‐2 and E₂ = 3.6 compared with controls (0); their relative proliferative effect was 18–38% (E₂ = 100%) with a relative proliferative potency of 4.5–8.9 (E₂ = 100). The ERα antagonist MPP inhibited the MCF‐7 cell proliferation induced by E₂ and AEs; on the contrary, the ERβ antagonist PHTPP exacerbated the proliferative response, showing that the AEs’ proliferative activity was mainly ERα‐mediated and apparently controlled by ERβ. Preliminary cytometric DNA flow analysis showed that AEs’ cell cycle S phase inducer property was lower than E₂ following the proliferative order: E₂ > butolame > prolame > pentolame, indicating pentolame with the weakest proliferative properties and being the safest of this series as a candidate for MHT.

Rodent ovariectomy is an experimental method to eliminate the main source of sexual steroids. This work explored for the first time the ovariectomy temporal changes induced in the hemostatic coagulation markers: prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin time (TT), and fibrinogen concentration (FIB) along with uterine weight on adult female CD1 mice and Wistar rats. Uterine weight (Uw) was assessed before ovariectomy (control), and 1, 3, 5, 7, 9, 16, and 21 days after surgery. PT, aPTT, TT and FIB were estimated the same days, using reported standard techniques. Ovariectomy decreased Uw, since day 1; and from day 10 to 21 reached the lowest values for both species. After day 1, mice hemostatic parameters changed (PT +10%, P<0.05; aPTT +53%, P<0.05; TT -24%, P<0.05; FIB +67%, P<0.05). Rats showed significant changes only in TT and FIB (TT -13%, P<0.001; FIB +65%, P<0.001). Neither mice PT, aPTT and TT, recovered control values after 21 days. In the rats from day 5 to 16 aPTT diminished (18-23%, P<0.05) recovering to control values on day 21, TT after 9 days and PT on day 16. In both species, FIB returned to its control values after 9 days. Ovariectomy differentially altered the PT hemostatic parameter of mice and rats indicating a non-equivalence among both species behaviour for experimental studies of blood coagulation.