Efficacy of gene delivery to the brain using AAV and ultrasound depends on serotypes and brain areas.

Focused ultrasound combined with intravenously injected microbubbles (FUS) is known to non-invasively, locally, and transiently increase the permeability of the blood-brain barrier (BBB). A promising approach for non-invasive gene delivery to the brain is to administer recombinant adeno-associated viruses (AAVs) intravenously and allow them to cross the BBB at precise FUS-targeted brain regions. FUS-AAV delivery has been achieved in animal models; however, the key elements influencing, guiding, and monitoring the success of FUS-AAV delivery to the brain remain largely unknown. We systematically compared the ability of AAV1, AAV2, AAV5, AAV8, AAV9, and AAVrg to enter four specific brain regions and transduce two main cell types: neurons and astrocytes. Our results demonstrate that the AAV serotype, the extent of FUS-induced BBB permeability, and the intrinsic properties of the targeted brain tissue influence the observed biodistribution, diffusion and transduction of AAV to cells of the cerebrovasculature and brain parenchyma. Non-invasive contrast-enhanced MR imaging was found to predict the efficacy of FUS-AAV delivery. Notably, we also found that AAVs with high biodistribution to peripheral organs result in low gene delivery to the brain when combined with FUS. Gene delivery by AAV1, AAV2, AAV5, AAV8 and AAV9 was highly and selectively localized to FUS-targeted brain areas. To obtain non-invasive gene delivery to multiple brain regions with one area of FUS-BBB modulation, we combined a modified AAV2 vector harboring enhanced retrograde transport properties (AAVrg) with FUS-mediated brain delivery. This allowed for gene delivery from the FUS-targeted site to multiple connected brain regions. This study demonstrates that MR imaging can be used as a non-invasive indication of AAV delivery to the brain, and that the properties of AAV serotypes influence the efficacy of gene delivery to the brain with FUS. AAVs that have minimal peripheral biodistribution are ideal candidates for enhanced, and perhaps exclusive with future serotypes, delivery to the brain with FUS. The characterization of parameters influencing FUS-AAV delivery to the brain are critical to the design of safe and efficient gene therapies, from preclinical studies to future clinical applications.

Allopurinol and valproic acid improve cardiac triglyceride and Na+-K+-ATPase activity independent of circulating aldosterone in female rats with glucose intolerance.

Context: Studies have shown that cardiac triglyceride accumulation and impaired Na+-K+-ATPase activity are linked to diabetes- related cardiovascular disease, particularly in women.Objectives: We hypothesised that allopurinol (ALL) and valproic acid (VPA) treatment would improve cardiac triglyceride and Na+-K+-ATPase activity independent of circulating aldosterone in Combined Oral Contraceptive (COC)-induced dysglycemiaMaterials and methods: Rats received COC (1.0 µg ethinylestradiol and 5.0 µg levonorgestrel; po) with or without ALL (1 mg; po) and VPA (20 mg; po) for 6 weeks.Results: COC-treatment led to impaired glucose tolerance, accumulated abdominal fat, dyslipidemia, elevated plasma MDA, PAI-1 and aldosterone levels and also reduced plasma nitric oxide bioavailability and cardiac Na+-K+-ATPase activity. However, either ALL or VPA treatment ameliorated these alterations comparably independent of elevated aldosterone levelDiscussion and conclusion: Our results suggest that either ALL or VPA would improve cardiac TG and Na+-K+-ATPase activity comparably in COC-treated rats, regardless of circulating aldosterone level.

Transgene distribution and immune response after ultrasound delivery of rAAV9 and PHP.B to the brain in a mouse model of amyloidosis.

Efficient disease-modifying treatments for Alzheimer disease, the most common form of dementia, have yet to be established. Gene therapy has the potential to provide the long-term production of therapeutic in the brain following a single administration. However, the blood-brain barrier poses a challenge for gene delivery to the adult brain. We investigated the transduction efficiency and immunological response following non-invasive gene-delivery strategies to the brain of a mouse model of amyloidosis. Two emerging technologies enabling gene delivery across the blood-brain barrier were used to establish the minimal vector dosage required to reach the brain: (1) focused ultrasound combined with intravenous microbubbles, which increases the permeability of the blood-brain barrier at targeted sites and (2) the recombinant adeno-associated virus (rAAV)-based capsid named rAAV-PHP.B. We found that equal intravenous dosages of rAAV9 combined with focused ultrasound, or rAAV-PHP.B, were required for brain gene delivery. In contrast to rAAV9, focused ultrasound did not decrease the rAAV-PHP.B dosage required to transduce brain cells in a mouse model of amyloidosis. The non-invasive rAAV delivery to the brain using rAAV-PHP.B or rAAV9 with focused ultrasound triggered an immune reaction including major histocompatibility complex class II expression, complement system and microglial activation, and T cell infiltration.

Sodium butyrate arrests pancreato-hepatic synchronous uric acid and lipid dysmetabolism in high fat diet fed Wistar rats.

High fat diet (HFD) is a risk factor for metabolic syndrome which is characterized by overt glucose dysmetabolism and tissue derangement. The liver and pancreas are important metabolic tissues with anatomical proximity sharing splanchnic and mesenteric circulation but it is unclear whether, there is an associated metabolic status between the two organs in health and disease. Uric acid (UA) hypersecretion and ectopic lipid accumulation are characteristic pathophysiology of an array of non-communicable diseases. Sodium butyrate (BUT) is reputed for therapeutic roles in metabolic derangement. Therefore, the present study investigated synchrony in hepatic and pancreatic UA and lipid metabolic status in HFD-induced glucose dysregulation and probed the beneficial effects of BUT. Twenty-four female Wistar rats were treated with normal rat chow and distilled water (po) or sodium butyrate (200 mg/kg; po) or high fat diet and distilled water (po) or high fat diet and sodium butyrate. Results showed that HFD increased plasma, pancreatic and hepatic triglyceride, triglyceride-glucose index, malondialdehyde, uric acid (UA), lactate dehydrogenase but reduced glucose-6-phosphate dehydrogenase. Histological analysis revealed hepatic and pancreatic architectural derangement and cellular degeneration in HFD-fed animals. However, BUT reversed the HFD-induced systemic, pancreatic and hepatic synchronous dysmetabolism with evidence of improved histology. HFD-induced lipid and UA alterations were synchronous in the pancreas and liver. BUT elicits beneficial effects on systemic and tissue HFD-induced deleterious metabolic changes which were synchronized in pancreas and liver of rats.

Combined but not single treatment with ethinylestradiol/levonorgestrel and spironolactone reduces plasminogen activator inhibitor-1 in insulin-resistant ovariectomised rats.

OBJECTIVE: Increased circulating level of plasminogen activator inhibitor-1 (PAI-1) is associated with menopausal oestrogen deficiency. We therefore hypothesised that the combined oral contraceptive (COC) with spironolactone (SPL) improves insulin resistance (IR) in ovariectomised (OVX) rats by reducing circulating PAI-1. METHODS: Twelve-week-old female Wistar rats were divided into sham-operated (SHM), OVX, OVX+SPL (0.25 mg/kg), COC (1.0 µg ethinylestradiol and 5.0 µg levonorgestrel) and OVX+COC+SPL rats treated with COC and SPL daily for eight weeks. IR was assessed by homeostatic model assessment of IR (HOMA-IR). RESULTS: Data showed that OVX rats had a higher HOMA-IR value that is associated with increased visceral adiposity, triglycerides (TG), total cholesterol/high-density lipoprotein cholesterol (HDL-C), TG/HDL-C, plasma insulin, GSK-3, corticosterone and decreased 17ß-oestradiol. However, these effects were attenuated in OVX+COC, OVX+SPL and OVX+COC+SPL rats compared to OVX rats. OVX rats had lower PAI-1 than SHM rats, whereas the beneficial effect on IR and other parameters by COC or SPL was accompanied with increased PAI-1. Improvement of IR and other parameters with combined COC and SPL in OVX rats was accompanied with reduced PAI-1. CONCLUSION: Taken together, COC or SPL improves IR independent of PAI-1, whereas a combination of COC and SPL in OVX rats ameliorates IR in a PAI-1-dependent manner.