Genetic knockdown of Klk8 has sex-specific multi-targeted therapeutic effects on Alzheimer's pathology in mice.

AIMS: Previous work in our lab has identified the protease kallikrein-8 (KLK8) as a potential upstream mover in the pathogenesis of Alzheimer's disease (AD). We showed pathologically elevated levels of KLK8 in the cerebrospinal fluid and blood of patients with mild cognitive impairment or dementia due to AD, and in brains of patients and transgenic CRND8 (TgCRND8) mice in incipient stages of the disease. Furthermore, short-term antibody-mediated KLK8 inhibition in moderate stage disease alleviated AD pathology in female mice. However, it remains to be shown whether long-term reversal of KLK8 overexpression can also counteract AD. Therefore, the effects of genetic Klk8-knockdown were determined in TgCRND8 mice. METHODS: The effects of heterozygous ablation of murine Klk8 (mKlk8) gene on AD pathology of both sexes were examined by crossbreeding TgCRND8 [hAPP+/-] with mKlk8-knockdown [mKlk8+/-] mice resulting in animals with or without AD pathology which revealed pathologically elevated or normal KLK8 levels. RESULTS: mKlk8-knockdown had negligible effects on wildtype animals but led to significant decline of amyloid beta (Aß) and tau pathology as well as an improvement of structural neuroplasticity in a sex-specific manner in transgenics. These changes were mediated by a shift to non-amyloidogenic cleavage of the human amyloid precursor protein (APP), recovery of the neurovascular unit and maintaining microglial metabolic fitness. Mechanistically, Klk8-knockdown improved Aß phagocytosis in primary glia and Aß resistance in primary neurons. Most importantly, transgenic mice revealed less anxiety and a better memory performance. CONCLUSIONS: These results reinforce the potential of KLK8 as a therapeutic target in AD.

Incidence and survival of HNSCC patients living with HIV compared with HIV-negative HNSCC patients.

PURPOSE: The aim was to analyze the incidence and survival of patients living with HIV (PLWH) with head and neck squamous cell carcinoma (HNSCC) and to compare with a control group of HIV-negative HNSCC patients. METHODS: Clinicopathological data and predictors for overall survival (OS) and disease-free survival (DFS) were investigated (2009-2019). RESULTS: 50 of 5151 HNSCC patients (0.97%) were PLWH, and 76% were smokers. Age ≤ 60 years, HIV-PCR ≤ 50 copies, CD4 cells ≤ 200/mm3, cART treatment, T and UICC classification, oral cavity and nasal/paranasal sinuses, and therapy were significantly associated with OS in univariate analysis. In the multivariate analysis, only age and HIV-PCR independently predicted OS. The OS of the 50 PLWH was not significantly altered compared with the 5101 HIV-negative controls. However, OS and DFS were significantly inferior in advanced tumor stages of PLWH compared with an age-matched control group of 150 HIV-negative patients. CONCLUSIONS: PLWH were diagnosed with HNSCC at a significantly younger age compared to HIV-negative patients. Taking into account patient age at initial diagnosis, both OS and DFS rates in PLWH are significantly worse compared with a matched control group of HIV-negative patients in advanced tumor stages UICC III/IV. The prognosis (OS) is improved when taking cART treatment, the HIV viral load is undetectable and CD4 count is high.

Particle deflection in a poly(dimethylsiloxane) microchannel using a propagating surface acoustic wave: size and frequency dependence.

We study the effect of a propagating surface acoustic wave (PSAW) with different frequencies on particles with different sizes in microfluidic channels. We find that the deflection critically depends on the applied frequency as well as on the particle size. For fixed frequencies, large particles are deflected and migrate perpendicular to the flow direction while smaller particles only follow the streamlines of the flow field. However, with increasing frequency of the PSAW above a size dependent limit, small particles are also actuated. This relation can be characterized by the wavenumber k and the particle radius r using the parameter κ = k · r. For the onset of deflection, we find a critical value κc ≅ 1.28 ± 0.20. Finally, we demonstrate how this device can be used for particle separation.

Real-time mid-infrared imaging of living microorganisms.

The speed and efficiency of quantum cascade laser-based mid-infrared microspectroscopy are demonstrated using two different model organisms as examples. For the slowly moving Amoeba proteus, a quantum cascade laser is tuned over the wavelength range of 7.6 µm to 8.6 µm (wavenumbers 1320 cm(-1) and 1160 cm(-1) , respectively). The recording of a hyperspectral image takes 11.3 s whereby an average signal-to-noise ratio of 29 is achieved. The limits of time resolution are tested by imaging the fast moving Caenorhabditis elegans at a discrete wavenumber of 1265 cm(-1) . Mid-infrared imaging is performed with the 640 × 480 pixel video graphics array (VGA) standard and at a full-frame time resolution of 0.02 s (i.e. well above the most common frame rate standards). An average signal-to-noise ratio of 16 is obtained. To the best of our knowledge, these findings constitute the first mid-infrared imaging of living organisms at VGA standard and video frame rate.

Quantum cascade laser-based hyperspectral imaging of biological tissue.

The spectroscopy of analyte-specific molecular vibrations in tissue thin sections has opened up a path toward histopathology without the need for tissue staining. However, biomedical vibrational imaging has not yet advanced from academic research to routine histopathology due to long acquisition times for the microscopic hyperspectral images and/or cost and availability of the necessary equipment. Here we show that the combination of a fast-tuning quantum cascade laser with a microbolometer array detector allows for a rapid image acquisition and bares the potential for substantial cost reduction. A 3.1 x 2.8 mm2 unstained thin section of mouse jejunum has been imaged in the 9.2 to 9.7 µm wavelength range (spectral resolution ~1 cm(-1)) within 5 min with diffraction limited spatial resolution. The comparison of this hyperspectral imaging approach with standard Fourier transform infrared imaging or mapping of the identical sample shows a reduction in acquisition time per wavenumber interval and image area by more than one or three orders of magnitude, respectively.