Background/Aim: The placenta is an extraembryonic organ necessary for foetal development. Due to its availability and high content of stem cells and growth factors, placenta tissue has found its application in regenerative medicine. The aim of this paper was to determine whether the age of the pregnant woman or the gestational age affects the morphology of the term placenta and whether placentas of advanced maternal age are suitable for application in regenerative medicine. Methods: In this research 30 placentas of healthy pregnant women, aged from 18 to 42 years and from 36 up to 41 weeks of gestational age were used for analyses. Tissue samples were stained with standard haematoxylin and eosin staining and immunohistochemical staining with anti-CD34 antibody. The parameters of volume density of chorionic villi, intervillous spaces and fibrinoids, as well as the thickness of the placental barrier were determined. Results: The volume densities of chorionic villi and fibrinoids were higher in placentas of advanced maternal age, as well as in placentas of gestational age from 38 to 41 weeks of gestation, while the volume of intervillous spaces was lower in these groups. With increased maternal and gestation age, the placental membrane thickens. Conclusion: When sampling placentas for regenerative medicine purposes, only the placentas from pregnant women younger than 35 years of age and whose gestational age are not exceeding 38 weeks should be selected.

Background: The process of prenatal hematopoiesis occurs in various anatomical locations, including the placenta. The placenta is not merely a temporary hematopoietic reservoir, but it is one of the key sites for the synthesis of hematopoietic stem cells (HSCs). This study aimed to investigate the presence, distribution, and immunoprofiles of HSCs in the human placenta during different gestational periods. Materials and Methods: Placental samples of different gestational ages (first, second, and third trimesters) were analyzed using classical hematoxylin and eosin staining and immunohistochemical staining for CD34, CD117, and CD41 markers, with HSC quantification through numerical areal density (N_A). Results: Highly immunoreactive CD34 HSCs were present in placentas throughout gestation, while highly immunoreactive CD117 and CD41 HSCs were observed during the first two trimesters. In the first trimester, HSCs were found within the lumen of blood vessels and as individual cells in the mesenchyme of chorionic villi. With advancing gestation, the number of HSCs in the mesenchyme of chorionic villi increased. Conclusions: Immunoreactive CD34, CD117, and CD41 cells are present in significant proportions in various parts of the placenta throughout gestation, indicating that the placenta provides a substantial proportion of HSCs for hematopoiesis.

Background: The process of prenatal hematopoiesis occurs in various anatomical locations, including the placenta. The placenta is not merely a temporary hematopoietic reservoir, but it is one of the key sites for synthesis of hematopoietic stem cells (HSCs). This study aimed to investigate the presence, distribution, and immunoprofiles of HSCs in the human placenta during different gestational periods. Materials and Methods: Placental samples of different gestational ages (first, second, and third trimesters) were analyzed using classical hematoxylin and eosin staining and immunohistochemical staining for CD34, CD117, and CD41 markers, with HSCs quantification through numerical areal density (NA). Results: Highly immunoreactive CD34 HSCs were present in placentas throughout gestation, while highly immunoreactive CD117 and CD41 HSCs were observed during the first two trimesters. In the first trimester, HSCs were found within the lumen of blood vessels and as individual cells in the mesenchyme of chorionic villi. With advancing gestation, the number of HSCs in the mesenchyme of chorionic villi increased. Conclusion: Immunoreactive CD34, CD117, and CD41 cells are present in significant proportions in various parts of the placenta throughout gestation, indicating that the placenta provides a substantial proportion of HSCs for hematopoiesis.

Acute mesenteric ischemia (AMI) is a life-threatening condition characterised by oxidative stress, inflammation, apoptosis, and necrosis of intestinal epithelial cells. Different drugs with vasoactive, antioxidant, and anti-inflammatory properties have been used to treat AMI. Levosimendan is a drug with proven anti-ischemic effects used in the management of acute congestive heart failure. This study evaluated the protective effects of levosimendan pretreatment on intestinal, as well as lung, heart, and kidney tissue in a rat model of mesenteric artery ischemia/reperfusion (I/R) injury. Male Wistar rats (N = 24) were divided into four groups: control, I/R, levosimendan (LS) 1 mg/kg i.p, and LS + I/R (1 mg/kg i.p. 30 min before injury). I/R by itself caused elevation of oxidative markers (thyobarbituric acid reactive species (TBARS), hydrogen peroxide (H₂O₂), super oxide anjon radical (O₂⁻), and nitrogen dioxide (NO₂⁻)), induced inflammation (macrophage infiltration and Interleukin-6 (IL-6) production), and apoptosis (nuclear factor kappa light-chain enhancer of activated B cells (NF-κB), cleaved caspase-3 (CC3), and terminal deoxy-nucleotidyl transferase (TdT)-mediated dUTP nick end labelling (TUNEL)). Levosimendan pretreatment significantly reduced oxidative stress markers and enhanced antioxidant defences (catalase (CAT), reduced glutathione (GSH), and superoxide dismutase (SOD)). Histological analysis revealed reduced mucosal damage and preserved goblet cells in intestinal tissue. Similar protective effects of levosimendan were observed in other organs such as lung, heart, and kidney. Immunohistochemistry showed reduced epithelial apoptosis and upregulation of antioxidant and anti-inflammatory proteins. These findings highlight levosimendan’s ability to protect mesenteric I/R tissue injury and multi-organ damage by suppressing oxidative stress, inflammation, and apoptosis, emphasising its therapeutic potential in clinical settings.