Methods: Pseudopregnancy (pc) was induced in cyclic Sprague-Dawley rats by sterile mating. Subcutaneous injection of nicotine tartrate (7.5 mg/kg/day) was scheduled from day 1 through day 5, day 5 through day 9 or day 1 through day 9 of pc. In another group of pseudopregnant rats, concomitant treatment of nicotine tartrate concurrently with progesterone (2 mg/day) was scheduled from day 1 through day 9 pc. Control groups received subcutaneous injections of vehicle only. Endometrial decidualization was induced on day 5 pc. On day 10 pc, animals were sacrificed.The degree of decidual growth and circulating levels of estrogen and progesterone were measured.
Results: The decidual growth in all the first three nicotine-treated groups of animals was significantly reduced, particularly in the animals treated with nicotine from day 1 through day 9 pc. Plasma estrogen levels were significantly elevated in animals treated with nicotine from day 1 through day 9 pc. Conversely, levels of plasma progesterone were found to be significantly attenuated in the same group of nicotine-treated animals compared to controls. Exogenous replacement of progesterone, however, caused a higher degree of endometrial decidualization compared to the nicotine-treated group but it was slightly less than when compared to control.
Conclusions: In conclusion, nicotine-induced progesterone deficiency with a corresponding elevation of estrogen may possibly attenuate the degree of endometrial decidualization in pseudopregnant rats.
MATERIAL AND METHODS: A) Effects of various doses of nicotine on in vitro embryonic development: Female mice were treated with 1.0, 3.0, or 5.0 mg/kg/day nicotine for 7 consecutive days. Animals were superovulated, cohabited overnight, and sacrificed. Embryos were cultured in vitro. Plasma was assayed. B) Effects of concomitant treatment of nicotine concurrently with various doses of gamma-TCT on in vitro embryonic development: Female mice were treated with nicotine (5.0 mg/kg/day), gavaged gamma-TCT of 30, 60, or 90 mg/kg/day or nicotine concurrently with gamma-TCT of 3 different doses for 7 consecutive days. Animals were superovulated, cohabited overnight, and sacrificed. Embryos were cultured and plasma was assayed.
RESULTS: A) Effects of various doses of nicotine on in vitro embryonic development: Number of hatched blastocysts decreased in 1.0 and 3.0 mg/kg/day nicotine groups. Nicotine at 5.0 mg/kg/day stopped embryo development at morula. MDA concentrations increased following all nicotine doses. B) Effects of concomitant treatment of nicotine concurrently with various doses of gamma-TCT on in vitro embryonic development: Embryo development was completed in all groups. MDA concentration increased only in the group treated with nicotine concurrently with 30 mg/kg/day gamma-TCT.
CONCLUSIONS: Nicotine impairs in vitro embryo development and increases MDA in plasma. The deleterious impact of nicotine on embryo development is reversed by supplementing gamma-TCT concurrently with nicotine.
METHODS AND RESULTS: We queried the Centers for Disease Control and Prevention's Wide-Ranging Online Data for Epidemiologic Research database among patients ≥15 years old from 1999 to 2020. VHD and its subtypes were listed as the underlying cause of death. We calculated age-adjusted mortality rate (AAMR) per 100 000 individuals and determined overall trends by estimating the average annual percent change using the Joinpoint regression program. Subgroup analyses were performed based on demographic and geographic factors. In the 22-year study, there were 446 096 VHD deaths, accounting for 0.80% of all-cause mortality (56 014 102 people) and 2.38% of the total cardiovascular mortality (18 759 451 people). Aortic stenosis recorded the highest mortality of VHD-related death in both male (109 529, 61.74%) and female (166 930, 62.13%) populations. The AAMR of VHD has declined from 8.4 (95% CI, 8.2-8.5) to 6.6 (95% CI, 6.5-6.7) per 100 000 population. Similar decreasing AAMR trends were also seen for the VHD subtypes. Men recorded higher AAMR for aortic stenosis and aortic regurgitation, whereas women had higher AAMR for mitral stenosis and mitral regurgitation. Mitral regurgitation had the highest change in average annual percent change in AAMR.
CONCLUSIONS: The mortality rate of VHD among the US population has declined over the past 2 decades. This highlights the likely efficacy of increasing surveillance and advancement in the management of VHD, resulting in improved outcomes.