•  本研究評估了低嵌合體水平（< 50%）胚胎的潛在活力。
• 研究表明嵌合胚胎可以發育成具有不同水平或類型嵌合體的整倍體健康嬰兒。
• 整倍體和嵌合囊胚移植的嬰兒之間沒有觀察到顯著差異。
• 如果患者沒有整倍體胚胎，則可以移植嵌合胚胎，它們有可能植入並發育成整倍體健康嬰兒。
• 這項研究對於諮詢單一嵌合胚胎移植後的臨床結果非常有價值。

. 2020 Sep;37(9):2305-2313.

 doi: 10.1007/s10815-020-01876-6. Epub 2020 Jul 4.Healthy live births from transfer of low-mosaicism embryos after preimplantation genetic testing for aneuploidy

• This study evaluated the potential viability of embryos with low mosaicism level (< 50%) by comparing the clinical outcomes of single mosaic versus euploid blastocyst transfer.  
• Our study indicated that mosaic embryos can develop into euploid healthy infants with various levels or types of mosaicism. 
• No significant difference was observed between infants from euploid and mosaic blastocyst transfers.
• If patients have no euploid embryos, mosaic embryos can be transferred as they have potential for implantation and development into euploid healthy infants. 
• This study is invaluable for counseling clinical results after single mosaic embryo transfers.

 對於 42 歲以上且僅存非整倍體胚胎的患者，鑲嵌染色體胚胎移植是比另外再施行IVF- PGT-A 週期更好的替代方案。

對於年齡小於 42 歲、無法進行額外施行IVF的患者，也應考慮鑲嵌染色體胚胎移植。 

. 2024 Mar;41(3):635-641.

 doi: 10.1007/s10815-024-03027-7. Epub 2024 Jan 17. Mosaic embryo transfer versus additional IVF with PGT-A Cycle: a decision model comparing live birth rate and cost

Mosaic embryo transfers are a superior alternative to an additional cycle of IVF with PGT-A for patients older than 42 whose only remaining embryos are non-euploid. Mosaic embryo transfers also should be considered for patients younger than 42 who are unable to pursue additional autologous IVF cycles

Ficoll-400 密度梯度可用於精蟲分離&產生了更高百分比的活的、成熟的、形態正常的精子。

分層方式: 5% (v/v) density top layer and 90% (v/v) Ficoll-400 density lower layer. 

密度比較: Ficoll density 1.2 g/ml

-----normal spermatozoa (1.17 g/ml)

-----immotile immature sperm cells having lower density of 1.02 g/ml,

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Ficoll-400 density gradient method as an effective sperm preparation technique for assisted reproductive techniques J Hum Reprod Sci. 2016 Jul-Sep; 9(3): 194–199.

Ficoll-400 density gradient yielded higher percentage of live, mature, morphologically normal spermatozoa in an isolated fraction as compared to other three techniques.

 使用密度梯度 density gradient centrifugation來分離狗精子性別的技術並不有效。

. 2018 Dec:199:84-92.  

Sperm sexing with density gradient centrifugation in dogs

•  Sperms were separated using gradients of Percoll® or Ficoll. 
• The percentage of sperm containing X and Y chromosomes was evaluated by qPCR. 
• The use of the Ficoll gradient resulted in the greatest sperm quality after centrifugation. 
• No sperm enhancement containing X or Y chromosome occurred with use of any of the methods 

1. Percoll® 54.8 ± 1.9 compared with 45.2 ± 1.9; 
2. Percoll® associated with Nycodenz® 53.2 ± 2.0 compared with 46.8 ± 2.0; 
3. Ficoll 55.0 ± 1.5 compared with 45.0 ± 1.5 
4. for the percentages of cells containing the X and Y chromosomes, respectively

• The technique of sexing dog sperm using density gradients was not effective for commercial application.

 嵌合胚胎mosaic中可能存在自我矯正機制，嵌合胚胎有可能發育成正常胚胎。

 大多數減數分裂衍生的非整倍體出現在卵子發生過程中。

40歲以上女性產生的卵母細胞中超過50%被證明是染色體異常。

有生育能力的男性精子中染色體異常的發生率在 3% 到 5% 之間。

準確診斷胚胎異常的機率為100%，而整倍體胚胎被分類為臨床適當的比例為61.9%。

J Assist Reprod Genet 2024 May;41(5):1127-1141.   

Hum Reprod. 2019 Apr 1;34(4):758-769.

• There may be a self-correcting mechanism in mosaic embryos, which allows some mosaicisms to potentially develop into normal embryos. 
•  Majority of meiotically derived aneuploidies arise during oogenesis. 
• more than 50 % of oocytes generated by women over the age of 40 years were demonstrated to be chromosomally abnormal. 
• The incidence of chromosome anomalies ranged between 3 and 5 % in the sperm of fertile men. 
• The probability of accurately diagnosing an embryo as abnormal was 100%, while the proportion of euploid embryos classified as clinically suitable was 61.9%. 

Figure 2

Blastocyst chromosomal profiles related to culture outcomes. Euploid blastocysts and those presenting with chromosomal gains and mosaicism were significantly more likely to remain viable 12 days post-fertilisation (dpf), compared to blastocysts with chromosomal losses or multiple aberrations.

 

 

影響人工受孕ㄉ成功率最重要ㄉ男性因素為總活動精蟲數total motile sperm (TMC)

較低的授精 TMC 與活產率降低有關，

較高的 TMC 與較高的活產率相關（TMC 1500-2000 萬（14.8%）相比≤500 萬（5.5%）

而從hCG注射到IUI的時間、精子製備方法和IUI超音波引導與成功率無關。

Intrauterine insemination performance characteristics and post-processing total motile sperm count in relation to live birth for couples with unexplained infertility in a randomised, multicentre clinical trial 

Human Reproduction, Volume 35, Issue 6, June 2020, Pages 1296–1305, 

• lower inseminate TMC were associated with a reduced live birth rate, 
• while time from hCG injection to IUI, sperm preparation method and ultrasound guidance for IUI were not associated with live birth success.
• Time from hCG trigger injection to IUI was not significantly associated with outcome.
•  Higher TMC was associated with greater live birth rate (TMC 15.1–20.0 million (14.8%) compared to ≤5 million (5.5%)) (aRR 2.09 (1.31–3.33)). However, live births did occur with TMC ≤ 1 million (5.1%).
• Higher TMC inseminated leads to an increase in live birth rate up to TMC ~20 million 
• 
  
  
  
• 
  

與單獨 IVF 以及與 Naturals 相比，12 週 IVF + TEBx 在胎盤和整個胚胎中 DNA 甲基化變化和差異基因表現的結果較差。這些變化反映在胎盤形態和血管密度的改變。

與 IVF 和 Naturals 相比，12 週 IVF + TEBx 後代，無論性別，都表現出更高的葡萄糖、胰島素、三酸甘油酯、更低的總膽固醇和更低的高密度脂蛋白，

結論: 胚胎養外胚層切片 (TEBx) 會影響早期發育過程中的胎盤和胚胎健康，有些改變會在發育後期得到解決，有些則會惡化，並引發成年後代的代謝變化。

Hum Reprod 2024 Jan 5;39(1):154-176.

Trophectoderm biopsy of blastocysts following IVF and embryo culture increases epigenetic dysregulation in a mouse model

• trophectoderm biopsy (TEBx) impacts placental and embryonic health during early development, with some alterations resolving and others worsening later in development and triggering metabolic changes in adult offspring. 
• at E12.5, IVF + TEBx had a worse outcome in terms of changes in DNA methylation and differential gene expression in placentas and whole embryos compared with IVF alone and compared with Naturals. These changes were reflected in alterations in placental morphology and blood vessel density. 
• we observed that 12-week IVF + TEBx offspring, regardless of sex, showed higher glucose, insulin, triglycerides, lower total cholesterol, and lower high-density lipoprotein compared to IVF and Naturals, 
• Figure 3. 
  Placental histology for embryonic day 12.5 and 18.5 mouse embryos. Placenta cross-sections at (A) Embryonic day (E) 12.5 using in situ hybridization with the junctional zone marker trophoblast specific protein alpha (Tpbpa), and counterstained with hematoxylin with the percentage of (B) labyrinth zone and (C) junctional zone shown. (D) E18.5 stained with hematoxylin–eosin and the percentage of (E) labyrinth zone and (F) junctional zone indicated.

子宮內膜緻密度（endometrial compaction, EC）定義為從卵泡期結束到胚胎移植（ET）之日的子宮內膜厚度差異

EC 在確定IVF著床率 方面的預測價值仍處爭議

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本篇研究顯示:  與沒有變化或增厚的女性相比，在 ET 當天子宮內膜緻密EC的女性的臨床懷孕率顯著更高。

Clinical pregnancy rates were significantly higher in women with endometrial compaction on ET day compared to women with no changes or thickening.  

https://link.springer.com/article/10.1007/s10815-023-02809-

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本篇研究顯示:  EC 在確定IVF著床率 方面的預測價值不高. 

J Assist Reprod Genet

. 2023 Nov;40(11):2513-2522.

 doi: 10.1007/s10815-023-02942-5. Epub 2023 Sep 20.

Can endometrial compaction predict live birth rates in assisted reproductive technology cycles? A systematic review and meta-analysis

Purpose: Endometrial compaction (EC) is defined as the difference in endometrial thickness from the end of the follicular phase to the day of embryo transfer (ET). We aimed to determine the role of EC in predicting assisted reproductive technology (ART) success by conducting a meta-analysis of studies reporting the association between EC and clinical outcomes of ART.Methods: MEDLINE via PubMed, Web of Science, Scopus, and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched from the date of inception to May 19, 2023. The primary outcome was live birth rate (LBR) per ET. Secondary outcomes were live birth or ongoing pregnancy per ET, ongoing pregnancy per ET, clinical pregnancy per ET, and miscarriage per clinical pregnancy.Results: Fifteen studies were included. When data from all studies reporting live birth were pooled, overall LBR rates were comparable in cycles showing EC or not [RR = 0.97, 95%CI = 0.92 to 1.02; 10 studies, 11,710 transfer cycles]. In a subgroup of studies that included euploid ET cycles, a similar LBR for patients with and without EC was noted [RR = 0.99, 95%CI = 0.86 to 1.13, 4 studies, 1172 cycles]. The miscarriage rate did not seem to be affected by the presence or absence of EC [RR = 1.06, 95%CI = 0.90 to 1.24; 12 studies].Conclusion: The predictive value of EC in determining LBR is limited, and assessment of EC may no longer be necessary, given these findings.

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 粒端telomere 長度 &  粒端酶telomerase活性 與卵子細胞 IVF結果關聯性

1. 人類卵母細胞TL在成熟過程中縮短
2. 與其他參數相比，TL 可以更好地預測 IVF 後的結果
3. 卵母細胞 TL vs D3 植入前胚胎的細胞質碎片---負關聯 
4. TL 長度與人類非整倍體異常aneuploid有關
5. aneuploid囊胚具有更長的TL  & 較低TA 
6. TL縮短與卵裂期胚胎的染色體分離錯誤無關
7. TA 比 TL 更能預測 IVF 治療後的懷孕結局
8. 卵顆粒細胞TA水平可以預測IVF治療的臨床結果
9. 較高的 TA 水準與臨床 IVF 結局呈正相關
10. 卵丘細胞TL 與卵母細胞質量和胚胎發育有關
11. TL功能和生殖潛力沒有直接關聯，而氧化 DNA 損傷對 IVF 結果和臨床懷孕的早期標記產生不利影響
12. TL異常與卵巢功能不全有關
13.  卵顆粒細胞 中較低的 TA 和較短的 TL 與 PCOS 和較長的不孕期有關
14. TA 和 TL 對於 PCOS 患者的胚胎品質和 IVF 結果沒有預後價值
15. 卵巢功能不全患者的顆粒細胞 TA 減少 TL 較短
16. IVF女性TL 顯著縮短

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11224194/

Studies focused on the relation between telomere length/telomerase activity and oocytes

1. Human oocyte telomeres shorten during maturation
2. TL provided a better predictor of outcome following IVF than other parameters
3. Oocyte TL negatively predicted cytoplasmic fragmentation in D3 preimplantation embryos
4. Telomere DNA length was associated with human aneuploidy development
5. Aneuploid blastocysts have longer telomeres but lower TA when compared to either euploid or mosaic/segmental human blastocysts
6. Telomere shortening was not related to chromosome segregation errors in the cleavage stage embryo
7. TA is a better predictor of pregnancy outcomes following IVF treatment than TL
8. TA levels in luteinized GCs may predict the clinical outcomes of IVF treatment
9. Higher TA levels were positively correlated with clinical IVF outcomes
10. TL in CCs is related to oocyte quality and embryo development
11. No direct association of telomere function and reproductive potential, while oxidative DNA damage adversely affected early markers of IVF outcome and clinical pregnancies
12. In young women, abnormal telomere homeostasis is linked to  ovarian insufficiency
13.  Lower TA and shorter TL in the GCs were linked with PCOS and a longer period of infertility
14. No prognostic value for the TA and TL in terms of embryo quality and IVF outcomes in PCOS patients
15.  Shorter LTL and GCTL in women with ovarian insufficiency compared with healthy controls
16. - Diminished granular cell TA in patients with ovarian insufficiency compared with healthy controls
17. Women undergoing IVF had statistically significant shorter telomeres compared to healthy controls

Evaluation of telomere length (TL) and telomerase activity (TA) on predicting in vitro fertilization treatment outcomes

Telomerase activity relative changes during gametogenesis, embryo development   

與冷凍胚胎植入ET相比，新鮮 ET 後懷孕的 Fetal fraction (FF) 甚至更低，這可能反映了與自然週期冷凍 ET 相比，新鮮 ET 後胎齡較小的傾向。

FF數值高低比較: 自然懷孕>FET>fresh ET

隨著母親 BMI 的增加，FF 顯著降低

• significant reduction in the FF in ART patients compared with naturally conceived pregnancies, which seems to be more pronounced after fresh ET compared with frozen ET.
• a significant reduction in FF with increasing maternal BMI 

Fetal fraction (FF) of cell-free DNA in pregnancies after fresh or frozen embryo transfer following assisted reproductive technologies 

Human Reproduction, Volume 35, Issue 6, June 2020, Pages 1267–1275, https://doi.org/10.1093/humrep/deaa110

I

SUMMARY ANSWER

This study shows a significant reduction in the FF in ART patients compared with naturally conceived pregnancies, which seems to be more pronounced after fresh ET compared with frozen ET.

MAIN RESULTS AND THE ROLE OF CHANCE

We found a reduction in FF in ART patients compared with naturally conceived pregnancies, and the reduction was more pronounced for ART pregnancies after fresh ET (mean FF = 0.049) compared with frozen ET (mean FF = 0.063) (multivariate analysis adjusted for maternal BMI, P = 0.02). Another multivariate analysis, adjusted for BMI and multiples of median (MoM) values for pregnancy-associated plasma protein-A (PAPP-A), demonstrated a significantly reduced FF for ART pregnancies (mean FF = 0.056) compared with naturally conceived pregnancies (mean FF = 0.072) (P < 0.0001). We found that FF was significantly reduced with increasing maternal BMI (P < 0.0001) and with decreasing MoM values of PAPP-A (P = 0.003).

WIDER IMPLICATIONS OF THE FINDINGS

Concurrent with other studies demonstrating a reduced FF for singleton pregnancies after ART treatment compared with naturally conceived pregnancies, we found a reduction in FF between the two groups. This is one of the first studies to examine FF in ART pregnancies after fresh ET compared with frozen ET, hence the existing knowledge is limited. We find that FF is even more reduced in pregnancies following fresh ET compared with frozen ET, which might possibly reflect the predisposition of being small for gestational age after fresh ET compared with natural cycle frozen ET.

Figure 2

Linear regression demonstrating the FF as a function of maternal BMI for the three groups of included pregnant woman. Pregnant woman with a fresh ET in a stimulated cycle (y = −0.0025x + 0.111, R = 0.386), pregnant woman with a frozen ET in a natural cycle (y = −0.0030x + 0.132, R = 0.560), and controls of naturally conceived pregnancies (y = −0.0021x + 0.124, R = 0.312).

破卵針GnRHa時間 與取卵時間間隔 範圍(≤ 35.22 h N = 104, 35.23–35.85 h N = 115, 35.86–36.35 h = 105 and ≥ 36.36 h, N = 114)

並沒顯著影響卵細胞產量和成熟率。

The GnRHa trigger to oocyte retrieval interval range in our cohort did not significantly affect oocyte yield and maturation rate.

rigger-to-retrieval time interval ranged from 32.03 to 39.92 h. The mean oocyte yield showed no statistically significant difference when comparing retrievals < 36 h (n = 240, 11.86 ± 8.6) to those triggered at ≥ 36 h (n = 198, 12.24 ± 7.73) (P = 0.6). 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11224053/

Box plot of retrieved oocytes by trigger to retrieval interval groups. *<36 h interval = 240 cycles, ≥ 36 h interval = 198 cycles

新的即時成像、非侵入性細胞標記技術  發現

 2 細胞階段胚胎只有只有其中一個細胞

會演化成80% 胚胎主體 未來的外胚層  內胚層（卵黃囊）和滋養外胚層（胎盤）

 Labeling and live imaging of human embryos reveal that the majority of the future body originates, mostly, from one of the 2-cell stage blastomeres. Descendants of the first 2-cell stage blastomere to divide contribute more asymmetric divisions at the 8-cell stage, which generate the small number of founding epiblast cells before implantation. 

https://www.cell.com/action/showPdf?pii=S0092-8674%2824%2900455-0

The first two blastomeres contribute unequally to the human embryo  

https://doi.org/10.1016/j.cell.2024.04.029 

SUMMARY 

Retrospective lineage reconstruction of humans predicts that dramatic clonal imbalances in the body can be traced to the 2-cell stage embryo. However, whether and how such clonal asymmetries arise in the embryo is unclear. Here, we performed prospective lineage tracing of human embryos using live imaging, non-invasive cell labeling, and computational predictions to determine the contribution of each 2-cell stage blastomere to the epiblast (body), hypoblast (yolk sac), and trophectoderm (placenta). We show that the majority of epiblast cells originate from only one blastomere of the 2-cell stage embryo. We observe that only one to three cells become internalized at the 8-to-16-cell stage transition. Moreover, these internalized cells are more frequently derived from the first cell to divide at the 2-cell stage. We propose that cell division dynamics and a cell internalization bottleneck in the early embryo establish asymmetry in the clonal composition of the future human body.