Table_4_Characterization of Non-hormone Expressing Endocrine Cells in Fetal and Infant Human Pancreas.DOCX

Context: Previously, we identified chromograninA positive hormone-negative (CPHN) cells in high frequency in human fetal and neonatal pancreas, likely representing nascent endocrine precursor cells. Here, we characterize the putative endocrine fate and replicative status of these newly formed cells.
Objective: To establish the replicative frequency and transcriptional identity of CPHN cells, extending our observation on CPHN cell frequency to a larger cohort of fetal and infant pancreas.
Design, Setting, and Participants: 8 fetal, 19 infant autopsy pancreata were evaluated for CPHN cell frequency; 12 fetal, 24 infant/child pancreata were evaluated for CPHN replication and identity.
Results: CPHN cell frequency decreased 84% (islets) and 42% (clusters) from fetal to infant life. Unlike the beta-cells at this stage, CPHN cells were rarely observed to replicate (0.2 ± 0.1 vs. 4.7 ± 1.0%, CPHN vs. islet hormone positive cell replication, p < 0.001), indicated by the lack of Ki67 expression in CPHN cells whether located in the islets or in small clusters, and with no detectable difference between fetal and infant groups. While the majority of CPHN cells express (in overall compartments of pancreas) the pan-endocrine transcription factor NKX2.2 and beta-cell specific NKX6.1 in comparable frequency in fetal and infant/child cases (81.9 ± 6.3 vs. 82.8 ± 3.8% NKX6.1+-CPHN cells of total CPHN cells, fetal vs. infant/child, p = 0.9; 88.0 ± 4.7 vs. 82.1 ± 5.3% NKX2.2+-CPHN cells of total CPHN cells, fetal vs. infant/child, p = 0.4), the frequency of clustered CPHN cells expressing NKX6.1 or NKX2.2 is lower in infant/child vs. fetal cases (1.2 ± 0.3 vs. 16.7 ± 4.7 clustered NKX6.1+-CPHN cells/mm2, infant/child vs. fetal, p < 0.01; 2.7 ± 1.0 vs. 16.0 ± 4.0 clustered NKX2.2+-CPHN cells/mm2, infant/child vs. fetal, p < 0.01).
Conclusions: The frequency of CPHN cells declines steeply from fetal to infant life, presumably as they differentiate to hormone-expressing cells. CPHN cells represent a non-replicative pool of endocrine precursor cells, a proportion of which are likely fated to become beta-cells.
Precis: CPHN cell frequency declines steeply from fetal to infant life, as they mature to hormone expression. CPHN cells represent a non-replicative pool of endocrine precursor cells, a proportion of which are likely fated to become beta-cells.

此前，我们在人类胎儿及新生儿胰腺中以高频率检出嗜铬粒蛋白A阳性、激素阴性细胞（chromograninA positive hormone-negative, CPHN），这类细胞大概率代表新生内分泌前体细胞。本研究旨在明确这些新发现细胞的潜在内分泌命运与复制状态。
研究目标：明确CPHN细胞的复制频率与转录特征，并将我们关于CPHN细胞频率的观测样本拓展至更大规模的胎儿及婴儿胰腺队列。
研究设计、研究场景与研究对象：本研究共纳入8例胎儿胰腺、19例婴儿尸检胰腺，用于评估CPHN细胞频率；另纳入12例胎儿胰腺、24例婴儿/儿童胰腺，用于分析CPHN细胞的复制情况与特征。
研究结果：从胎儿期至婴儿期，胰腺胰岛内的CPHN细胞频率下降84%，小簇状分布的CPHN细胞频率下降42%。与该阶段的β细胞不同，CPHN细胞极少发生复制（CPHN细胞复制率为0.2±0.1%，胰岛激素阳性细胞复制率为4.7±1.0%，p<0.001），这一点可通过CPHN细胞无论分布于胰岛还是小簇中均不表达Ki67得以证实，且胎儿组与婴儿组之间无显著差异。尽管在整体胰腺组织中，多数CPHN细胞表达泛内分泌转录因子NKX2.2以及β细胞特异性转录因子NKX6.1，且胎儿组与婴儿/儿童组的阳性细胞频率相当（胎儿组NKX6.1阳性CPHN细胞占总CPHN细胞的比例为81.9±6.3%，婴儿/儿童组为82.8±3.8%，p=0.9；胎儿组NKX2.2阳性CPHN细胞占总CPHN细胞的比例为88.0±4.7%，婴儿/儿童组为82.1±5.3%，p=0.4），但婴儿/儿童组中表达NKX6.1或NKX2.2的簇状CPHN细胞频率显著低于胎儿组（婴儿/儿童组每mm²簇状NKX6.1阳性CPHN细胞为1.2±0.3，胎儿组为16.7±4.7，p<0.01；婴儿/儿童组每mm²簇状NKX2.2阳性CPHN细胞为2.7±1.0，胎儿组为16.0±4.0，p<0.01）。
研究结论：从胎儿期至婴儿期，CPHN细胞的频率急剧下降，这可能是由于其分化为激素表达细胞所致。CPHN细胞构成了一个非复制型的内分泌前体细胞库，其中一部分大概率定向分化为β细胞。
研究概要：CPHN细胞的频率从胎儿期至婴儿期急剧下降，其会逐渐成熟并表达激素。CPHN细胞构成了非复制型的内分泌前体细胞库，其中一部分大概率定向分化为β细胞。