Validation of a methodology for neuro-urological and lumbosacral stimulation studies in domestic pigs: a humanlike animal model

Porcine spinal cord injury model for translational research across multiple functional systems

Animal models are necessary to identify pathological changes and help assess therapeutic outcomes following spinal cord injury (SCI). Small animal models offer value in research in terms of their easily managed size, minimal maintenance requirements, lower cost, well-characterized genomes, and ability to power research studies. However, despite these benefits, small animal models have neurologic and anatomical differences that may influence translation of results to humans and thus limiting the success of their use in preclinical studies as a direct pipeline to clinical studies. Large animal models, offer an attractive intermediary translation model that may be more successful in translating to the clinic for SCI research. This is largely due to their greater neurologic and anatomical similarities to humans. The physical characteristics of pig spinal cord, gut microbiome, metabolism, proportions of white to grey matter, bowel anatomy and function, and urinary system are strikingly similar and provide great insight into human SCI conditions. In this review, we address the variety of existing porcine injury models and their translational relevance, benefits, and drawbacks in modeling human systems and functions for neurophysiology, cardiovascular, gastrointestinal and urodynamic functions.

Magnetic soft robotic bladder for assisted urination

The poor contractility of the detrusor muscle in underactive bladders (UABs) fails to increase the pressure inside the UAB, leading to strenuous and incomplete urination. However, existing therapeutic strategies by modulating/repairing detrusor muscles, e.g., neurostimulation and regenerative medicine, still have low efficacy and/or adverse effects. Here, we present an implantable magnetic soft robotic bladder (MRB) that can directly apply mechanical compression to the UAB to assist urination. Composed of a biocompatible elastomer composite with optimized magnetic domains, the MRB enables on-demand contraction of the UAB when actuated by magnetic fields. A representative MRB for a UAB in a porcine model is demonstrated, and MRB-assisted urination is validated by in situ computed tomography imaging after 14-day implantation. The urodynamic tests show a series of successful urination with a high pressure increase and fast urine flow. Our work paves the way for developing MRB to assist urination for humans with UABs.

A maternal high-fat/low-fiber diet impairs glucose tolerance and induces the formation of glycolytic muscle fibers in neonatal offspring

PURPOSE

In our previous study, the maternal high-fat/low-fiber (HF-LF) diet was suggested to induce metabolic disorders and placental dysfunction of the dam, but the effects of this diet on glucose metabolism of neonatal offspring remain largely unknown. Here, a neonatal pig model was used to evaluate the effects of maternal HF-LF diet during pregnancy on glucose tolerance, transition of skeletal muscle fiber types, and mitochondrial function in offspring.

METHODS

A total of 66 pregnant gilts (Guangdong Small-ear Spotted pig) at day 60 of gestation were randomly divided into two groups: control group (CON group; 2.86% crude fat, 9.37% crude fiber), and high-fat/low-fiber diet group (HF-LF group; 5.99% crude fat, 4.13% crude fiber).

RESULTS

The maternal HF-LF diet was shown to impair the glucose tolerance of neonatal offspring, downregulate the protein level of slow-twitch fiber myosin heavy chain I (MyHC I), and upregulate the protein levels of fast-twitch fiber myosin heavy chain IIb (MyHC IIb) and IIx (MyHC IIx) in soleus muscle. Additionally, compared with the CON group, the HF-LF offspring showed inhibition of insulin signaling pathway and decrease in mitochondrial function in liver and soleus muscle.

CONCLUSION

Maternal HF-LF diet during pregnancy impairs glucose tolerance, induces the formation of glycolytic muscle fibers, and decreases the hepatic and muscular mitochondrial function in neonatal piglets.