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High-resolution magnetic resonance imaging quantitatively detects individual pancreatic islets.

Lamprianou S, Immonen R, Nabuurs C, Gjinovci A, Vinet L, Montet XC, Gruetter R, Meda P - Diabetes (2011)

Bottom Line: In all cases, MR images were acquired in a 14.1 Tesla scanner and correlated with the corresponding (immuno)histological sections.MEHFMRI also detected a significant decrease in the numerical and volume density of islets in STZ-injected mice.However, in the latter measurements the loss of β-cells was undervalued under the conditions tested.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland. smaragda.lamprianou@unige.ch

ABSTRACT

Objective: We studied whether manganese-enhanced high-field magnetic resonance (MR) imaging (MEHFMRI) could quantitatively detect individual islets in situ and in vivo and evaluate changes in a model of experimental diabetes.

Research design and methods: Whole pancreata from untreated (n = 3), MnCl(2) and glucose-injected mice (n = 6), and mice injected with either streptozotocin (STZ; n = 4) or citrate buffer (n = 4) were imaged ex vivo for unambiguous evaluation of islets. Exteriorized pancreata of MnCl(2) and glucose-injected mice (n = 6) were imaged in vivo to directly visualize the gland and minimize movements. In all cases, MR images were acquired in a 14.1 Tesla scanner and correlated with the corresponding (immuno)histological sections.

Results: In ex vivo experiments, MEHFMRI distinguished different pancreatic tissues and evaluated the relative abundance of islets in the pancreata of normoglycemic mice. MEHFMRI also detected a significant decrease in the numerical and volume density of islets in STZ-injected mice. However, in the latter measurements the loss of β-cells was undervalued under the conditions tested. The experiments on the externalized pancreata confirmed that MEHFMRI could visualize native individual islets in living, anesthetized mice.

Conclusions: Data show that MEHFMRI quantitatively visualizes individual islets in the intact mouse pancreas, both ex vivo and in vivo.

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Related in: MedlinePlus

MRI detects islets in situ in a living mouse. High magnifications of MR images of the exteriorized pancreas of a living, anesthetized mouse reveal a pancreatic substructure like that observed ex vivo, including the presence of elongated vessels and ducts (white arrows) and round-ovoid bodies of small size (green arrows). Histological correlation showed that these small bodies corresponded to individual pancreatic islets. Scale bar: 1 mm. Insets show low magnification views of the same pancreas. P = pancreas; s = spleen. *Position of the plastic pin that secured the pancreas. (A high-quality digital representation of this figure is available in the online issue.)
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Figure 5: MRI detects islets in situ in a living mouse. High magnifications of MR images of the exteriorized pancreas of a living, anesthetized mouse reveal a pancreatic substructure like that observed ex vivo, including the presence of elongated vessels and ducts (white arrows) and round-ovoid bodies of small size (green arrows). Histological correlation showed that these small bodies corresponded to individual pancreatic islets. Scale bar: 1 mm. Insets show low magnification views of the same pancreas. P = pancreas; s = spleen. *Position of the plastic pin that secured the pancreas. (A high-quality digital representation of this figure is available in the online issue.)

Mentions: To determine whether high-field MRI can detect islets in vivo, the pancreas was exteriorized through an abdominal incision, without affecting its normal blood flow and innervation (Supplementary Fig. 1). This externalization minimized the effects of breathing and bowel movements on imaging and allowed for the unambiguous identification of the pancreas, which is not immediate in the noninvasive imaging of mice. Under these conditions, MRI revealed intrapancreatic structures similar to those observed in the ex vivo samples, including putative pancreatic islets of Langerhans, which appeared as intralobular whitish bodies (Fig. 5). Correlative histology confirmed that these bodies were bona fide islets (Fig. 5).


High-resolution magnetic resonance imaging quantitatively detects individual pancreatic islets.

Lamprianou S, Immonen R, Nabuurs C, Gjinovci A, Vinet L, Montet XC, Gruetter R, Meda P - Diabetes (2011)

MRI detects islets in situ in a living mouse. High magnifications of MR images of the exteriorized pancreas of a living, anesthetized mouse reveal a pancreatic substructure like that observed ex vivo, including the presence of elongated vessels and ducts (white arrows) and round-ovoid bodies of small size (green arrows). Histological correlation showed that these small bodies corresponded to individual pancreatic islets. Scale bar: 1 mm. Insets show low magnification views of the same pancreas. P = pancreas; s = spleen. *Position of the plastic pin that secured the pancreas. (A high-quality digital representation of this figure is available in the online issue.)
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3198086&req=5

Figure 5: MRI detects islets in situ in a living mouse. High magnifications of MR images of the exteriorized pancreas of a living, anesthetized mouse reveal a pancreatic substructure like that observed ex vivo, including the presence of elongated vessels and ducts (white arrows) and round-ovoid bodies of small size (green arrows). Histological correlation showed that these small bodies corresponded to individual pancreatic islets. Scale bar: 1 mm. Insets show low magnification views of the same pancreas. P = pancreas; s = spleen. *Position of the plastic pin that secured the pancreas. (A high-quality digital representation of this figure is available in the online issue.)
Mentions: To determine whether high-field MRI can detect islets in vivo, the pancreas was exteriorized through an abdominal incision, without affecting its normal blood flow and innervation (Supplementary Fig. 1). This externalization minimized the effects of breathing and bowel movements on imaging and allowed for the unambiguous identification of the pancreas, which is not immediate in the noninvasive imaging of mice. Under these conditions, MRI revealed intrapancreatic structures similar to those observed in the ex vivo samples, including putative pancreatic islets of Langerhans, which appeared as intralobular whitish bodies (Fig. 5). Correlative histology confirmed that these bodies were bona fide islets (Fig. 5).

Bottom Line: In all cases, MR images were acquired in a 14.1 Tesla scanner and correlated with the corresponding (immuno)histological sections.MEHFMRI also detected a significant decrease in the numerical and volume density of islets in STZ-injected mice.However, in the latter measurements the loss of β-cells was undervalued under the conditions tested.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland. smaragda.lamprianou@unige.ch

ABSTRACT

Objective: We studied whether manganese-enhanced high-field magnetic resonance (MR) imaging (MEHFMRI) could quantitatively detect individual islets in situ and in vivo and evaluate changes in a model of experimental diabetes.

Research design and methods: Whole pancreata from untreated (n = 3), MnCl(2) and glucose-injected mice (n = 6), and mice injected with either streptozotocin (STZ; n = 4) or citrate buffer (n = 4) were imaged ex vivo for unambiguous evaluation of islets. Exteriorized pancreata of MnCl(2) and glucose-injected mice (n = 6) were imaged in vivo to directly visualize the gland and minimize movements. In all cases, MR images were acquired in a 14.1 Tesla scanner and correlated with the corresponding (immuno)histological sections.

Results: In ex vivo experiments, MEHFMRI distinguished different pancreatic tissues and evaluated the relative abundance of islets in the pancreata of normoglycemic mice. MEHFMRI also detected a significant decrease in the numerical and volume density of islets in STZ-injected mice. However, in the latter measurements the loss of β-cells was undervalued under the conditions tested. The experiments on the externalized pancreata confirmed that MEHFMRI could visualize native individual islets in living, anesthetized mice.

Conclusions: Data show that MEHFMRI quantitatively visualizes individual islets in the intact mouse pancreas, both ex vivo and in vivo.

Show MeSH
Related in: MedlinePlus