Another Missing Link

RISK FACTORS FOR CRANIAL CRUCIATE DISEASE IN DOGS

The harvest at the SCAF Community Garden is well and truly in marking the end of a surprisingly good growing season, despite the drought, all thanks to our group of brilliant volunteers. What a joy the garden and the people in it have been throughout the year, serving as a powerful reminder of just how important the basic, often taken for granted elements, of fresh air, movement, earth, plants, animals and people are for keeping us healthy in mind and body. The more sedentary, solitary and computer based our jobs and daily lives become, the more vital it is to find a physical and social counterbalance for ourselves. It has also been a fortnight of gremlins with many things breaking down or just not quite working out as expected. These patches in time where nothing seems to go as it should can seriously test our resilience. I have learnt over the years that during stressful times when I can feel my cortisol levels starting to rise, I need to quite literally ‘keep grounded’ and do something in nature, such as planting, tending plants, walking by a flowing river or amongst trees.

I have written several times before about cholesterol and statins but had only reached the level of differentiating between HDL (the ‘good’ cholesterol) and HDL (the previously so called ‘bad’ cholesterol) whilst at the same time I have been adamant about how important cholesterol is in all mammalian bodies. Cholesterol is the main sterol in all mammals and the bodies regulation and use of lipoproteins is considered by some authors to be the ‘third immune system’. As a reminder, cholesterol has a vital role in the plasma membrane of all mammalian cells, modulating membrane fluidity, permeability and signaling. It is found in the endoplasmic reticulum membrane, regulating the metabolism of this essential intracellular organelle in every single cell of the body. Cholesterol is involved in cellular proliferation, immune cell modulation and embryonic signaling, and just in case this is not enough, it is the precursor of bile acids, oxysterols and all steroid hormones i.e. the glucocorticoids, mineralocorticoids and the sex steroids. This created a dissonance; how could cholesterol be so important to life, involved in every single cell of the human and animal body and yet be so potentially dangerous? So dangerous that millions of humans are having their cholesterol levels driven down by drugs known as statins.

As a vet, the answer was staring me in the face, as in an incredibly simplified way, we would only recognise crude changes in blood cholesterol and triglyceride levels in animals with metabolic disease e.g. the Cushing’s disease horse or dog, pancreatitis, diabetes or thyroid disease. Dyslipidaemia (dysfunction in the metabolism of lipids) plays a crucial role in cardiovascular disease and other metabolic diseases.

This week in my studies I have tapped into a seam of knowledge that has provided an incredibly important missing link, to make the whole thing start to make sense. It is not the levels of normal native LDL that is a problem for us, it is when the LDL becomes oxidised that the trouble starts. Our immune cells do not react to native LDL or HDL as these are recognised parts of self and not targets for our immune system. Immune cells called macrophages, do however clean up damaged oxidised LDL (called small dense low density lipoprotein) forming foam cells; it is these foam cells and the sdLDL (small density or oxidised LDL) that play a major role in most cardiovascular and metabolic diseases in humans and animals with the exception of the small percentage of inherited lipid metabolic diseases. So what creates oxidised LDL?

The most important factors that lead to the creation of oxidised LDL are:

1. High circulating insulin levels (insulin resistance) - glucose metabolism dysregulation

2. High Omega 6 fatty acids

3. AGE (Advanced Glycation End) products created e.g. cooking food at high temperatures

4. Leaky Gut allowing lipopolysaccharides (LPS - bacterial wall products) to enter the bloodstream causing a metabolic endotoxaemia

5. Toxins:

   1. Mycotoxins from moulds either within us or exposure from our environment

   2. Plastics

   3. Phthalates e.g. found in many body, makeup and shampoo products

   4. BPA e.g. the lining of cans

   5. Glyphosate and other herbicides and pesticides

Once again we have been focusing on the wrong thing. The obsession with measuring everyone’s cholesterol levels and frightening everyone into taking a drug to lower their cholesterol levels, has done a great job in preventing us from asking the right questions. Are we even testing the right thing? No we are not, as testing LDL and HDL gives no indication of how much of that cholesterol is damaged and therefore likely to cause disease, and if the oxidised LDL level is high, what is the underlying cause? In the US at least, there are tests available to measure sdLDL but even if that test is not available, if you do have a raised LDL in a blood test, you need to have further investigation to find out how much of it is damaged and why. If we do not treat the underlying cause, the patient will not be cured and I can safely say that not one patient is suffering from statin deficiency.

NEW EVIDENCE FOR RISK FACTORS FOR CRANIAL CRUCIATE LIGAMENT DISEASE

The cranial cruciate ligament (CrCl) is one of the most important stabilisers in the canine knee (stifle), preventing excessive back and forth movement in the bones of the joint. Rupture and tearing of this ligament are one of the most common reasons for hindlimb lameness and pain, ultimately leading to arthritis in the joint due to abnormal loading and excessive wear and tear.