Initiation of bone lesions in young growing pigs and the importance of maternal

nutrition

Allen D. Leman Swine Conference

Laura AmundsonUniversity of Wisconsin-Madison

September 19, 2016

Outline

• Insights from the hypovitaminosis D kyphotic pig

• Endochondral ossification

• Molecular signals important in bone metabolism affected by vitamin D

• Conclusions on nutritional inputs to bone lesions

Kyphosis – idiopathic disease induced by vitamin D, Ca & P deficiencies

Rortvedt et al., 2012.Hypovitaminosis D kyphotic pig model

Femur

Hypovitaminosis D Induced KyphosisAbnormalities detected in multiple locations

Vertebrae

-D

+D

Histology Part #1

The anterior vertebral endplates of the kyphoticvertebrae (solid arrows) were less ossified than those of the control

vertebrae (dashed arrow), indicating that the deformity is likely a growth abnormality rather than an insufficiency type fracture.

Kyphotic

H&E

Trichrome

Control

H&E

Trichrome

Images courtesy of Dr. Matt Halanski

Uncoupled Endochondral Ossification?

z

Growth plate

Resting zone

Proliferative zone

Hypertrophic zone

Invading capillary

Osteoblast

Osteoclast

Endochondral Ossification

Amundson et al., 2016 (not yet reported)

Hypovitaminosis D Induced KyphosisMaternal Diet Carryover Effect

Which signaling pathways are altered by hypovitaminosis D to induce gross bone lesions

and abnormalities?

Factors Important in Bone Matrix Turnover

• Matrix Metalloproteinases (MMP)• MMP9 (gelatinase)• MMP13 (collagenase)• Zinc dependent enzymes

• Vascular Endothelial Growth Factor (VEGF)

z

Growth plate

Type II Collagen

Type X CollagenMMP13VEGF

MMP9

MMP13VEGF

Type I Collagen

VEGF

ECM

VEGF

MMP13

MMP9

MMP13MMP9

VEGF

chondrocyte

osteoblast

osteoclast

Adapted from Lin et al., 2002

VEGF

ECM

VEGF

MMP13

MMP9

MMP13MMP9

VEGF VEGF

chondrocyte

osteoblast

osteoclast

Angiogenesis

Adapted from Lin et al., 2002

VEGF

ECM

VEGF

MMP13

MMP9

MMP13MMP9VEGF

chondrocyte

osteoblast

osteoclast

VEGF

Angiogenesis

Adapted from Lin et al., 2002

Molecular Data

• Initial hypothesis:• Decreased expression of femur and vertebrae

MMP9, MMP13, and VEGF mRNA

Femur Relative MMP9 mRNA expression

Femur relative MMP9

Molecular Data

• Initial hypothesis:• Decreased expression of femur and vertebrae

MMP9, MMP13, and VEGF mRNA

• Articular joint diseases• Human, horse, and canine data• INCREASED MMPs• TIMPs – Tissue Inhibitor of Metalloproteinase

MMPs : TIMPs

Interactions and Balance

Conclusions• It’s complicated!

• Carryover of maternal nutrition is important in neonatal bone health

• Nutrients act locally (not just systemically) to couple endochondral ossification

• Nutrient interactions on molecular signaling in bone are not clearly established

• The kyphotic pig model provides a tool to understand the initiation and development of bone lesions

• Balance is key!

Swine Research & Teaching Center

SRTC Staff

Jamie ReichertJeff BoothSam TraceKeri Graff

Lab Support

Laura HernandezJimena Laporta

AcknowledgementsTom Crenshaw

Questions