Heart Disease and the Genesis of Pearls

[Lagoon Island Pearls]

I've been back in the field collecting specimens. I set out this year to revisit a theory on the incidence of pearl formation related to heart disease.

In almost every specimen found to contain pearls, a great percentage were found within <50% of the radius from the center of the anatomy. This suggests heart involvement. Mussels don't have hearts as a single organ, insomuch as laddered pericardium. From the heart, capillary ducts and valves interconnect the vascular system which also supplies the reproductive systems through a series of gonoducts. Together with skin, muscle and fascia theses form the pallial mantle.

I've started looking much closer at the heart in every case now and it seems the incidence higher than previously anticipated.

Microscopic analysis is revealing some interesting things. It was exciting to find pearls with visible sacs attached to the linings of the heart. No only is this revealing, it's revolutionary! Why? It is because we are witnessing the birth of pearls.

While other causes for onset are known, this one is different because these pearls are sterile and rather than having a nucleus itself, they are the nucleus of the lesions themselves.

Now that I have sacs, I can stain for protease. A protease is an enzyme that catalyzes proteolysis, breaking down proteins into minor polypeptides or single amino acids, thus stimulating the formation of new protein products. That's going to take time because my surgery is crude, but I'm searching new micro-biopsy tooling.

Stenosis is the obvious result, but not the cause which is yet to be determined. Mollusks have an open circulatory system, therefore this is not a valve issue. Pearls appear to form at any position along the vessels. Many will irrupt from the sac, thus becoming lodged elsewhere within the circulatory system, sometimes restricting blood (hemolymph) flow.

I've also noticed several pearls attached near the hinge and always on the right shell. Another clear sign of natural pearls from maladies at or near the heart.

 

[Lagoon Island Pearls]

Scarcely a few microns in size, new pearls born to the world.

 

[SteveM]

Dave, are you developing this research individually or in concert for eventual publication?

 

[Lagoon Island Pearls]

Dave, are you developing this research individually or in concert for eventual publication?

Individually. At least up to the genetics part. If that's where I end up, I'll be content with providing the materials.

 

[Lagoon Island Pearls]

Here are images of the shells from where the soft tissues in the previous images resided.

The pericardium parallels the dorsal line along the interior of the right valve. Medial to the organ (likely highest blood pressure point) a blister pearl occurs adjacent to the hinge. Otherwise healthy, unaffected ligaments.

Motion abnormality caused by inflammation of the vestibular mantle surrounding one or more of the attachment ligaments. Conjoined pearl.

Heart disease with acute cellulitis and stenosis. Multiple pearl irruptions conjoined to the valves with aragonitic bridging.

Chronic heart disease. Extreme localization, motion non-union, atrophic or otherwise necrotic cells present. Loss of programed cell behavior, granular bridging and surfaces.

 

[SteveM]

When collecting the specimens are there exterior signs of disease prior to dissection? What is it about the pathology that causes the microscopic lesions? Are they nascent cysts of mantle tissue anticipated to produce shell material, or might they be precursors to what in non-Mollusca Metazoans would be considered bezoars?

 

[Lagoon Island Pearls]

When collecting the specimens are there exterior signs of disease prior to dissection? What is it about the pathology that causes the microscopic lesions? Are they nascent cysts of mantle tissue anticipated to produce shell material, or might they be precursors to what in non-Mollusca Metazoans would be considered bezoars?

Excellent questions.

External signs. Sometimes, but not as a rule. From livestock, I tend to target large, over-mature shells with shell anomalies. From deadstock (demised by whatever reason) they'll sometimes gape. External to internal bore-type parasites are visible from the outside, but those internal blisters are not normally affecting the heart. There are pockets and patches which tend to produce more pearls, while some none at all. Generally at the benthic line as opposed to the top of the reef. Once shucked, I'm able to palpate the heart. Even though the creature is physically dead, the tissue remains viable for a surprisingly long amount of time. This makes shipping abroad with minimal "fixes" optimal. It's my hope a lab somewhere will step up, so we can get this done.

Pathology. That's the bridge to cross where I am now. Now that I have the pearl sacs, I'll need to run the gauntlet of specificity stains. I've ordered E-Osin B for now, but will likely try Y as well. In the short term, bacterial etiology needs to be visited. Viruses after that. Then genetics.

Bezoars. These are indigestible materials in the viscera. I've seen them in GI tracts before, but this isn't that. These pearls are formed in the walls of the heart chambers. They are sterile and non-specific (at least to my knowledge).

My hearts of hearts suggests it's a combination of factors. In the animal kingdom, autoimmune disease is widespread, especially from infections.
In a small percentage of any population, creatures may live and die by it without our knowledge, especially in non-specific cases. While it's very well known bacterial infections give rise to autoimmune disease, sadly the lesions given rise by it are often sterile and absent of visible nuclei.

A great number of the specimens I've examined, irrespective of degree appear to be otherwise healthy, living full term life cycles.

I'm still leaning onset factors by histocompatibility antigens. In pteriomorphs it's at it's greatest, pteriods not as much and heterodonta, almost never. That fact alone, screams genetics.