Emerging evidence suggests that transforming growth factor-␤ (TGF-␤) is an important mediator of diabetic nephropathy. We showed previously that short-term treatment with a neutralizing monoclonal anti-TGF-␤ antibody (␣T) in streptozotocin-diabetic mice prevents early changes of renal hypertrophy and increased matrix mRNA. To establish that overactivity of the renal TGF-␤ system mediates the functional and structural changes of the more advanced stages of nephropathy, we tested whether chronic administration of ␣T prevents renal insufficiency and glomerulosclerosis in the db͞db mouse, a model of type 2 diabetes that develops overt nephropathy. Diabetic db͞db mice and nondiabetic db͞m littermates were treated intraperitoneally with ␣T or control IgG, 300 g three times per week for 8 wk. Treatment with ␣T, but not with IgG, significantly decreased the plasma TGF-␤1 concentration without decreasing the plasma glucose concentration. The IgG-treated db͞db mice developed albuminuria, renal insufficiency, and glomerular mesangial matrix expansion associated with increased renal mRNAs encoding ␣1(IV) collagen and fibronectin. On the other hand, treatment with ␣T completely prevented the increase in plasma creatinine concentration, the decrease in urinary creatinine clearance, and the expansion of mesangial matrix in db͞db mice. The increase in renal matrix mRNAs was substantially attenuated, but the excretion of urinary albumin factored for creatinine clearance was not significantly affected by ␣T treatment. We conclude that chronic inhibition of the biologic actions of TGF-␤ with a neutralizing monoclonal antibody in db͞db mice prevents the glomerulosclerosis and renal insufficiency resulting from type 2 diabetes.

In this study, we report on the remarkable two-photon excited fluorescence efficiency in the "biological window" of CaF(2):Tm(3+),Yb(3+) nanoparticles. On the basis of the strong Tm(3+) ion emission (at around 800 nm), tissue penetration depths as large as 2 mm have been demonstrated, which are more than 4 times those achievable based on the visible emissions in comparable CaF(2):Er(3+),Yb(3+) nanoparticles. The outstanding penetration depth, together with the fluorescence thermal sensitivity demonstrated here, makes CaF(2):Tm(3+),Yb(3+) nanoparticles ideal candidates as multifunctional nanoprobes for high contrast and highly penetrating in vivo fluorescence imaging applications.

The technological development of quantum dots has ushered in a new era in fluorescence bioimaging, which was propelled with the advent of novel multiphoton fluorescence microscopes. Here, the potential use of CdSe quantum dots has been evaluated as fluorescent nanothermometers for two-photon fluorescence microscopy. In addition to the enhancement in spatial resolution inherent to any multiphoton excitation processes, two-photon (near-infrared) excitation leads to a temperature sensitivity of the emission intensity much higher than that achieved under one-photon (visible) excitation. The peak emission wavelength is also temperature sensitive, providing an additional approach for thermal imaging, which is particularly interesting for systems where nanoparticles are not homogeneously dispersed. On the basis of these superior thermal sensitivity properties of the two-photon excited fluorescence, we have demonstrated the ability of CdSe quantum dots to image a temperature gradient artificially created in a biocompatible fluid (phosphate-buffered saline) and also their ability to measure an intracellular temperature increase externally induced in a single living cell.

High glucose and exogenous TGF-beta1 exert disparate effects on the expression of alpha1 and alpha5(IV) collagen. However, high glucose and TGF-beta1 coordinately induce the production of alpha3(IV) collagen and VEGF in the podocyte. The HG-induced increases in alpha3(IV) collagen and VEGF proteins are mediated by the TGF-beta system. By increasing the expression of TbetaRII, high glucose may augment the response of the podocyte to ambient levels of TGF-beta1.

The future perspective of fluorescence imaging for real in vivo application are based on novel efficient nanoparticles which is able to emit in the second biological window (1000-1400 nm). In this work, the potential application of Nd(3+) -doped LaF(3) (Nd(3+) :LaF(3) ) nanoparticles is reported for fluorescence bioimaging in both the first and second biological windows based on their three main emission channels of Nd(3+) ions: (4) F(3/2) →(4) I(9/2) , (4) F(3/2) →(4) I(11/2) and (4) F(3/2) →(4) I(13/2) that lead to emissions at around 910, 1050, and 1330 nm, respectively. By systematically comparing the relative emission intensities, penetration depths and subtissue optical dispersion of each transition we propose that optimum subtissue images based on Nd(3+) :LaF(3) nanoparticles are obtained by using the (4) F3/2 →(4) I11/2 (1050 nm) emission band (lying in the second biological window) instead of the traditionally used (4) F(3/2) →(4) I(9/2) (910 nm, in the first biological window). After determining the optimum emission channel, it is used to obtain both in vitro and in vivo images by the controlled incorporation of Nd(3+) :LaF(3) nanoparticles in cancer cells and mice. Nd(3+) :LaF(3)nanoparticles thus emerge as very promising fluorescent nanoprobes for bioimaging in the second biological window.

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AngII stimulates the podocyte to produce alpha3(IV) collagen protein via mechanisms involving TGF-beta and VEGF signalling. Alterations in alpha3(IV) collagen production may contribute to GBM thickening and perhaps proteinuria in diabetes.