Multipotent stromal cells from human marrow home to and promote repair of pancreatic islets and renal glomeruli in diabetic NOD/scid mice

Abstract

We tested the hypothesis that multipotent stromal cells from human bone marrow (hMSCs) can provide a potential therapy for human diabetes mellitus. Severe but nonlethal hyperglycemia was produced in NOD/scid mice with daily low doses of streptozotocin on days 1-4, and hMSCs were delivered via intracardiac infusion on days 10 and 17. The hMSCs lowered blood glucose levels in the diabetic mice on day 32 relative to untreated controls (18.34 mM +/- 1.12 SE vs. 27.78 mM +/- 2.45 SE, P = 0.0019). ELISAs demonstrated that blood levels of mouse insulin were higher in the hMSC-treated as compared with untreated diabetic mice, but human insulin was not detected. PCR assays detected human Alu sequences in DNA in pancreas and kidney on day 17 or 32 but not in other tissues, except heart, into which the cells were infused. In the hMSC-treated diabetic mice, there was an increase in pancreatic islets and beta cells producing mouse insulin. Rare islets contained human cells that colabeled for human insulin or PDX-1. Most of the beta cells in the islets were mouse cells that expressed mouse insulin. In kidneys of hMSC-treated diabetic mice, human cells were found in the glomeruli. There was a decrease in mesangial thickening and a decrease in macrophage infiltration. A few of the human cells appeared to differentiate into glomerular endothelial cells. Therefore, the results raised the possibility that hMSCs may be useful in enhancing insulin secretion and perhaps improving the renal lesions that develop in patients with diabetes mellitus.

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Scheme. 1.

Experimental design.

Fig. 1.

Effects of hMSCs on blood glucose and mouse insulin levels in STZ-induced diabetic NOD/scid mice. (A) Blood glucose levels in untreated diabetic mice (STZ) and in hMSC-treated diabetic mice (STZ + hMSCs). Values are mean ± SE from three experiments. (B) Blood glucose levels in untreated diabetic mice and diabetic mice infused with human fibroblasts (STZ + hFibroblasts). Differences on day 10 reflect variations in untreated mice before fibroblasts were infused. Values are mean ± SD. (C) Blood levels of mouse insulin on day 32 in diabetic mice (STZ), hMSC-treated diabetic mice (STZ + hMSCs), and normal mice. Values are mean ± SD. ∗, Values that differ from each other with P = 0.0018.

Fig. 2.

Histology of pancreas from diabetic mice (STZ-treated), hMSC-treated diabetic mice (STZ + hMSCs), and control mice (Normal) at day 32. (A) Morphology of islets stained with hematoxylin and eosin. Sections (5-μm) are magnified ×400. (B) Islets labeled antibodies for mouse insulin. Nuclei labeled with DAPI. Sections (5-μm) are magnified ×400. (C) Insulin pixels per islet. Values are mean ± SD. ∗, Values that differ from each other with P = 0.0079. (D) Islets per section. Values are mean ± SD. ∗, Values that differ from each other with P = 0.002. n = 4 or 5.

Fig. 3.

IHC of pancreas from hMSC-treated diabetic NOD/scid mice on day 32. Sections were colabeled with antibodies for human cells (β2-microglobulin) and mouse insulin. Nuclei were stained with DAPI. Sections (5-μm) are magnified ×400. Dotted line, outlines of ducts; arrows, human cells; arrowheads, human cells colabeled for mouse insulin.

Fig. 4.

Renal glomeruli from diabetic mice (STZ), hMSC-treated diabetic mice (STZ + hMSCs), and control (Normal) mice on day 32. (A) Glomeruli stained with periodic acid-Schiff. Sections (8-μm) are magnified ×400. (B) Glomeruli labeled with antibodies to mouse macrophages/monocytes. Sections (8-μm) are magnified ×400. (C) Pixels per glomerulus in sections labeled with antibodies to mouse macrophages/monocytes. Values are mean ± SD; n ≥ 20 sections per mouse. ∗, Values that differ from each other with P < 0.005.

Fig. 5.

Renal glomeruli from hMSC-treated diabetic mice on day 32. Sections (5-μm) are magnified ×400. (A–D) Glomeruli labeled with antibodies for human nuclei antigen and mouse/human fibronectin. Some human cells that are colabeled have rounded morphology of mesangial cells. (E--H) Glomeruli labeled with antibodies for human nuclei antigen and mouse/human podocalyxin. No colabeling is detected. (J–L) Three-dimensional views of cells in glomeruli labeled for human nuclei antigen and for mouse/human endothelial cells (CD31). Some human cells appear to be colabeled and have the elongated morphology of endothelial cells. As indicated in the three-dimensional views, the CD31 epitope is present on several aspects of the human cells. Arrows, human cells; dotted arrows, planes for deconvolution; dotted lines, outlines of glomeruli. For additional three-dimensional deconvolved images, see Figs. 7–9 and Movie 1, which are published as supporting information on the PNAS web site.